Text

Basic Considerations for Assembling a CLOSED-CIRCUIT Television System
	ML20049H982
Person / Time
Issue date:	05/31/1977
From:	Prell J; NRC OFFICE OF STANDARDS DEVELOPMENT
To:	;
References
	NUREG-0178, NUREG-178, PB-268-480, NUDOCS 8203110094
	Download: ML20049H982 (51)
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U.S. DEPARTMENT OF COMMERCE Nationaliechnicallnformation Service PB 268 480 Basic Considerations for Assembling a Closed-Circuit Television System Nuclear Regulatory Commission, Washington, O'C May 77 k

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PB 268 480 NUREG-0178 BASIC CONSIDERATIONS FOR ASSEMBLING A CLOSED-CIRCUIT TELEVISION SYSTEM

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MP 611-7 Divisien of Sitings Health & Safeguards Standards Office of Standards Developtrent 8 8. Caniraci/c'a=< sa-Nuclear Regulatory Comission Washinoton, D.C. 20555 Organsaatson Name and Address

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Wash'ngton D.C. 20555 s

la. supplemen att Aotes

16. Abstracts This report describes the various subcomponents and options available in assembling renancial considerations an optirum CCTV system for a particular application, the nf asserbling and maintaining a CCTV system and other considerations which affect s

CCTV systems such as determining the proper lighting and improving the monitor s

observer's performance. Special emphasis has been placed on the use of CCTV systems for security applicaticns, but the information presented is also applicable to non-security uses. This report is an attempt to cover all factors of a CCTV system in sufficient detail so that a potential user is not totally dependent upon the manufacturer for the selection and raintenance of his CCTV system.

11. Aey toras ac4 occument Analysis. Ile. Descriptors 17b. IJennifiers,'Open-EndeJ Terms l

17c. CosATI Fie:J C-osp lb. Aeastability scarement

19. Security Liass (Ihis

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NUREC 0178 BASIC CONSIDERATIONS FOR ASSEMBLING A CLOSED-CIRCUlT TELEVISION SYSTEM J. A. Prell l

Manuscript Completed: May 1977 Date Published: May 1977 i

Division of Siting, Health and Safeguards Standards Of face of Standards Development U.S Nuclear Regulatory Commission Washington. D. C. 20555

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l TA8LC DF CONTENTS Y

Chapter Pale 1.

IntrodJCiton.........................................

I 1

1.1 Dbjective.....................................

I 1.2 t'ses...............................................

2 1.3 Gene ra l De s c ri p t i on..............................................

2.

T he Te l e v i s i on Came ra...................................................

3 2.1 General 5 cope......................

3 2.2 lenses............................

3 2.3 Light Sensing Clements........................

6 2.3.1 Antimony Trisulfide Vidicon..................................

6 7

2.3.2 Sensitive Vidicon........

2.3.3 Silicon-Diode Vidicon......................................

7 2.3.4 I n t er.s e f i ed V i d i con..........................................

8 2.3.5 Stitcon Intensified Target and Intensified Silicon Intens i f ied Ta rge t T abes...................................

8 2.3.6 Sol id-S ta te Tel ev i s i on C imera s.............................

9 2.3.7 Second Generation Iraga I nte ns i f 6 ers.......................

9 9

2.3.8 Dynamic Range.........................

2.3.9 Resolution and frequency Band =toth....

10 3.

D i s t r i bu t i on 5ys t em.....................................................

12 3.1 Video Transmissiot...................................................

12 3.2 Contral Signal Transmission.......................................

14 4.

Cl osed Ci rc ui t Tel ev i s i on Mon i to rs.......................................

16 16 4.1 Technical Considerations......

4.2 Control Room Considerations................................

16 f..

Video Tape Recorders...................................................

18 5.1 Genera 1.........................................................

18 5.2 Tyres and 512:5..........................................

18 5.3 Maintenance.........................................................

19 6.

Pan / Tilt unlis........................................................

20 7.

Image Motion Sensors...................................................

21 8.

Additional Considerations................................................

22 22 8.1 Lightirg..........................................................

8.2 Cost of Dwnership..............,.................................

25 8.2.1 Daylight Vidicon.............................

25 8.2.2 Sensitive Vidicons..........................

25 8.2.3 5111 con-Diode Vidicons................

27 8.2.4 Intensified Vidicons........................

27 8.2.5 Silicon Intensified Target Tube Careras......................

27 8.2.6 Intensified $11tcon Intensified Target Tube Cameras..........

27 8.2.7 Solid-State Cameras.......................

28 i

TABLt OF CCNT[%TS (ccntinued)

@aAter, Page 8.3 T e s t i ng a nd M a i n te na nc e.......................................

28

8. 3.1 Carera..............

28 8.3.2 fransmissten System......

30 30 2.3.3 televiston Muntter..........

8.3.4 Ilectronic Industries Asscciatten Resnlution Test CNart.....

30 31 8.3.5 v f 1eot a t +.....................

31 8.3.6 L19nting.....

31 8.3.1 Powe r................................................

8.4 Obtaining Optimum Performance f ron Pontter Observers................

32 4

Fnys i ca l SeC ur i t y Us es...................................

33 9.1 taterior uses.....................................................

33

9. l.1 Ca, eras......................................................

35 9.1.2 Transmission L ink.........

35 9.1.3 Monitors...................................................

35 36 9.1.4 Video face Recorder....................................

9.1.5 Lightin9...................

36 9.2 Interioruses.......................................................

36 9.2.1 Cameras.....................................................

36 35 9.2.2 Transmission Link........................................

9.2.3 Monitors.....................

36 9.2.4 Lighttn9....................................................

37 9.3 Personnel Identification............................................

37 37 9.3.1 Cameras...................

9.3.2 C o n t ro l F o t n t...............................................

37

9. 3. 3 Mo n i t o rs..................................................

37 9.3.4 Em e rg e nc t e s..................................................

38 9.4 A s s es sne n t o f A l a rms................................................

38 9.4.1 Cameras......................................................

38 9.4.2 Transmission Link........

38 9.4.3 Monitors.....................................................

38 4 4.4 Lightirg....................................................

39 i

i REFERENCES..................................................................

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FOREWORD 1he parpose of this report is to present to the potential aer of a closed circuit televi-tion (CCTV; system gertinent informattas that mill be wseful to him in assembling, operating, and maintaining the optim e CCTV syst s for eeeting his s.articalar needs. This report does not give an in-dectn tethnical treatnent of CCIV systems. Instead, this report addresses itself to the warloss r.ajor co-tponents of a CCTV system and discusses tnote f actors that inflwence a CCTV system's perf ontence, reintenance, and price.

ACrA0dtIDGEFiki The majority of information appearing in this docet =as obtained from a large sector of the CCTV industry whose cooperation and constructive criticism have Seen greatly ap;reciated.

The author is particularly indebted to the various laboratortes and of fites of tre Energy #esesrch and Development Aeministration such as the Oak Ridge 'rea Of fice. the hevaca Area Cf fice, and Mason & Hangar. Silas-Mason ar.d Co. Inc., whose review helped to better direct the occument towards those individuals for whom it is intended. 5;ecial thanks alsc go to the author's co-workers, whose critique of this document contributed to a more meaningful report.

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Ih1RCDUCTIO't 1.1 OXective, The objective of this docune.it is to pruent to tne rea$er information that would be of *elp to him in assetoling the optimum closed circuit television (CC*.') system for a particular app 11-cation. Special emphasts is placed on the use of CCTV syste-s for security applications.

However, a large portion of the report is directe0 toward providing information as to what a CCTV system consists of, the strong and weak points of a CCTV system. tne financial consideratiors of asserbling an1 maintaining a CCTV system, and other f actors tnat influence the performance of a CCTV system. This information may be equally applicable to CCTV s, stems being assembled for e-security appitcations.

I.. assembiteg the optimum CCTV system. the design engineer first needs to te f amiliar witn each component of the CCTV system, its rela'.ionship to other corponents, and the various opttcns, designs, and tra$ coffs that are available. In addition, he has to know the enviromental con-straints placed upon the systen, the degree of resolution requiret'. the financial constraints, and the projected maintenance requirements. This report is an et. apt to cover all these factors in suf ficient Metall to allow the user some independence f rom the manuf acturer in the selection and maintenance of the CCTV system.

1.2 Um A CCTV systera can be used whenever observation is needed and where direct vie =ing is irpes.

sible. undesirable, or inconvenient. It not only can provide a better wantage point for observa-tion but also can augment the sensitivity. contrast discrimination, and spectral range of the TV ca* eras can be placed in all tym s of enviroments fro, vault-type rooms under human eye.

constant lighting conditions to outdoor environments where t*e lighting can vary from bright sunlight to overcast night conditions and teerperatures can vary fran -40' to 125'F.

The first step in deciding what type of CCTV system is needert.s determining the locattua and use of the CCTV system. For some operations. CCTV is helpful (1) in providing protection to operating personnel by making it possible to increase the distance between control personnel aM a dangerous operation. (2) in monitoring operaticns occurring in an entreme or uncomfortable environment. (3) in coordinating a number of different operations. (4) in preparing educaticul videotapes. (5) in inspecting machinery, control equipment. 49d production line?. and (6) in various security applications such as observing sensitive areas, renotely assessing alarms, cc identifying personnel desiring entrance into sensitive areas.

Af ter it has been decided where and for what pur; e CCTV is to be used, each subcomporeet of the CCTV system has to be properly specified in order to achieve the desired cptimum perforw ance for the environment chosen.

1

e 1.3 Ceneral Descrittion A very basic CCTV syste, consists of a camera lens, which is used to focus the light from the subject onto a light sensor in the camera; the TV camera, which converts the light into an electrical signal; a transmission medium, c ually coastal cable used to transmit the electrical signal to a TV renitor; the TV monitor. which converts the electrical signal into a video picture; power supplies to provide power to the camera, monitor, and any electrical accessories that ray be present; and s monitor observer wN views the scene. (See Figure 1.) Dependirg on the intended use the basic CCTV system can te further espanded. Adding such accessories as a pan / tilt assem-bly; an environmental housing witn windshield wiper heater, and cooling fan; an image intenst-fler; a virlectape recorder; a zoom lent; an autoratic fris; a video motion detector unit; and a battery power supply increases the versatility of the casic CCTV system. obtain the optimum CCTV system, tie various parameters for each subsyiten need to be known and tradeoffs rade. Most of these certinent parawters vnd other considerations are presented in succeeding chapters.

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e TV MONI TOR 1F b MONITOA OSs!RVE R FIGURE 1 - BASIC COMPONENTS OF A CCTV SYSTEM i

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THE TELEVISION CAMERA 2.1 General Scr ge The functien of a TV carw ra is to convert the light from the scene ceming througn the lens it.to an electrical signal tnat can te transmitted to a remote location and reconverted to an imge on a cathode ray tube monitor. The visual image from tre lens is focused on the sensing elenent f acolate, which, when scanned. provides an electrical output. CCTV cameras are generally grouped according to the light sensitivity of their sensing eterrent. TV cameras can also be grouped into monochrome (black and whita) or color, according to the kind of picture they record for transmis> ton. Color centras are best used for industrial training and color-dependent proc.

essing applications. Black and white cameras are generally used for surveillance. property protection, r.aterial handling and control, underwater surveille.ce, and video motion. sensor applications. Cameras normally used in security applications range in price from 1350 to $9.000 per unit. tre price being determined prir.cipally by the type cf lens and light. sensing element used.

This chapter will discuss in detail considerations in choosing the proper 1cns for a CCTV camera, the various types of light. sensing elements used in CCTV cameras, and the meaning and ef fects of dynamic range and resolution.

2.2 Lees The pur@se of the CCTV lens is to focus the lignt from the target area onto the sensing element of tre TV camera. The distance between the sensing element and the effective center of the iens (w'en the lens is focused at infinity) is called the focal length and is usually espressed inmillin.eters(mm). The greater the focal length, the larger will te the image of a distant object. However, the width of field, or field of view, at a given distance from the cap. era narrows with increasing focal length. Thus, telephoto lenses having a long focal length (e.g.,

80 to 300 m) will have a narrower field of view at a given distance than will a wide. angle lens with a short focal length (e.g.

15 m). The proper lens for a TV camera is determined by the distance to tre scene to be viewed and the width and height

of the object or scene to be viewed.

Thus, the user of a CCTV system should know where he plans to place the carera and the size of the object or scere he wishes to view before choosing a lens. Once these are known, the proper lens can be ceterutned using a guide similar to Figure 2 (Ref.1).

A room lent allows the user to vary the width of field of the viewed scene by varying the focal length of the lens. Thus, if tN= user wishes to use a wide-angle lens for norral Survell-larce work witn the ability to enlarge a portion of a suspected target area, a room lens can be used. In determining the amount of eagnification a zoom lens cr fixed lens will provide, the forrula given telow can be used. A 25 sti focal length lens is considered the reference lers and has been lef t ed as having a magnification of 1 (Ref. 2):

The height cf the video picture transmitted by the camera is always 75% of the width of the video picture. The ratio of height to width is called the aspect ratto (i.e.

3 to 4).

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Problem: Where should the Cr.TV ca tra GIVEN: the distance fran camera to ssbject cautpped with a 150-m lens be located to (object distance).

fill a Vidicon frame witn 49 object r in, I

wide and 4 in. High?

I A.

Locate distance on vertical scale.

B.

Select focal length of zoom to be used Answer: Considering the entreire teleshoto and re.d diagonal lines.

position (150-m focal length). roceed C.

Where the distance line intersects as follows:

diagonal line. read horizoetal scale top or bottori for width of area covered.

1.

Locate 6 inch (0.5 feet) width en D.

To detenaine hetcht of area covered.

horizontal scale.

rultiply width b/ 0.75.

7.

Find diagonal line for 150-m focal length.

ADDIT 10'tAL U5ES TOR GRJFH:

3.

Fsllow width line vertically to point of inters.rction with diagonal of focal To detemine focal lengt% when the object

length, distance and midth of coverage are given.

4.

Read the distance on rignt er lef t vertical distance scale. Ca M ra positicn should be 5.75 feet frori ebject.

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Magnification = d" ih'"N D 4-Figure 2 can also tw ssed in eooste; e soon leas tf first cet+~taing t=e largest and srallest width of target area to t4 ct, served tf a cae+ra.

.'ca-1 emes steally *a.e rcre glass e?crents than a fined focsl length lens ' Pef. L Caa%' N t*e relatt.e posittr.c cf teese glass elecents changes the focal leng'h. =*tch casse-6*e =t Str o' t*e vuw: Scere to craNa. Most iv. len'.es ct.aSe their focel lengte f ror 20 nn to 100 m f or a 5.1 row-er 15 er to 150 rei for a 10:1 :cori.

ThJs. a particular viewed tar';et can :e eagat f'ee ettve 5 se ;' 't*es t*e.tae. angle position.

There are also range eatenders. =htc* rwittol, tne ' scal lengt'. and re.ro zoors, whim decrease tre focal lengt's (Ref. 3).

An importart featu*e of a lens *. t*e amet c' le;*t *t ca' rass to t*e Itght-sensitive element. This is 6 m n as tee spee3 :* tN ices.

l* ts reas. red Dy tre ratio of the fecal length of the 16ns to tne e*fective 3 a eter c' t'e detre lees osening. tels ratto is called the f-neber. For enac'ple, a tens.ita a 35 es-rocal leagte en2 e nestv a etstructed diameter r

of 18.4 mm will have a lers steed of *:1.1.

- e S*411er tne '-aater. t*e faster the lens (i.e.,

the more lif,t the lens at11 transmit: Gef. 4).

w ver, rest foc.,5 and cepth of field are at a sneller opentN. Most 'erses are dest taed no tnat t*e saarpest 14.;es a e prodsced 2 or 3 f-stops *

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from wide open. Tre use of f:16 or f:22 lenses se.Ct-. ca crai is rare, e cept in controlled s

conditions where trigmt Itq*ttag is acc. In sec "tr applica!?:ns. =kere tac se of ato e-norrel ligt ting is socettres not practical. it is cove 9 place : eperate t*e lens wide c wn at f:1.4 and still cttain sharp s q.s cf cejec ts at 1:ag Jtstances. Zoor' 1 esses are avullable with a minimum f-n sber of f:1.4. Dat are t ascall, 8:2.5 ce f:2.2. ftsed lerses are seatlable witn a rini um f.ns.ter of f:1.4 (Aef. 5).

Another para,eter involved tn (noming tr.* pre:er ler.s fer a particolar location is the gercentage of til.rtnattor. lost in t** seas (lens traesr esstoa ef f tetency). This is significant w*en the CCTV system is' to te uset er ; -Itqnt level sitwattoes and riust te known tefore deter-eining the proper light-sensteg elcreat for a CC!i camera. Nst !CIV leases have a lens trans-elssion ef ficiency t'etwee t M. and 90 as determne: ty tne croosition of the glass lens coatings, nurber of ele"ents. etc. (Ce'. 3).

A simple algetraic equation, givea telow. sho-s tre relattonsnto tet een scene illumination, scere reflectance lens transmittance. Icns steed, ar4 tens output light level (Ref. 6):

I, R T Iio " UTiF where I,, a faceplate illumination (fortcandles)**

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= scene illumination (fc)

Closing down one f-stop redaces the light passed t'y the lens ty cne half.

eethe footcandle (fe) is the English unit of tiltriination. It is *he lituaination on a surface 1 foot from a point source with a lurtnous intensity of I Candela.

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R = scene reflectance (percentage /100)

T = lens transmission ef *it ency (parcentage/100) i h

fe = f-number of the lens =

1 pening This equation ccn be used by a designer to help setemine the sensitivity of the light senstnj eierent needed for a camera under given lighting cer.Jitions. For e;.a:rple, assu.ne the scene reflects 20. Of the ligSt incidert upon it. the desired lens is 90'. ef ficient, the lens has a s&*ed of f:1.9. and the user'l.as a scene illuminatf or., in the darkest portion, of I fc (twilight conditions). The light reacning the sensing unit of the camera will be

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= 0.0.25 fc.

ao 4(1.9)e This figure then gives the user the sensitivity required of the TV camera's sensing elemes.t to adequately survey the der 6est area, assuming the lens will always te eperated wide open (i.e..

f:1.9).*

2.3 Light-sensing Elemeny The hear t of any TV camera is its light-sensing element, known as a vidicon, Cameras are senerally classified a co ding to the type aad sensitiv'ty of their vidicons. The differences are determined L/ the photo. conductive layer on the vidicon's f aceplate. For higher sensitivity, ar image intensifier can be added to tke vidicon. Daylight cameras are qualitatively cefined as being able to trod 6e a clear video picture wnlle operating from fairly high illumination levels.

Such as bright sunlight (10* fc). down ta twilight conditions (1 fc) (Ref. 6). Cameras that can operate in light coeialtions less than I fc are called low-light-level (LLL) TV cameras. The most sensiti e o. LLL TV cameras can cperate down to overcast night condi*fons (40~5 fc) (Ref. 5).

v 2.3.1 Antimony Tri5ulfide Vidicon Most daylight cameras use an antinony trisulfide (5ba5 ) vidicon tube (Rafs. 6, 7) as the 3

lignt-sensing device. This vidicon retaires approximately 0.1 fc of faceplate illumination (light reaching the sensing element f.m the lens) in order to produce a clear ricture. This 0.1 fc of faceplate illumination represents the lower limit of what is classified as a daylight can.ra. Antimony trisulfide vidicons are eusceptible to target damage if they are overexposed to very t,right lights. For this reason. care should be taken in tositioning the cameras so they never face the sun. In addition, antirony trisulfide vidicon cameras used in fixed surveillance sitaations where the scene has high contrast and the camera is sharply focused may have the dis-played scene perunently burried in on the vidicon in a relatively short period of time. This is accoripanied by decreasing sensitivity. which in time will render the vidicon useless for detec-tion purposes. When this occurs. one can place a cap over the lees of a cameea that has been in place six months (arbitrary) without af fectirg the image at the monitor. Antimony trisalfide For further information concerning lighting effects and tradeoffs, the reader is directed to Chapter 8.

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vidicon (no.'mally called standard vidicon) cameras also exhibit lag ctwracteristics. or picture snear, when viewing a moving scene. However, these vidicons are much Ytss espensive to replace than some of the more sensitive vidicons. and they scrk well in well-11Yseinated areas. In addition. they are rugged, simple to operate. easy to install. and compact; they have a good signal-to noise retfo, a relatively long life. 4 good environmental tempernture range. good resolution characteristics, and a large dynaste range in light level (Refs. $. 8).

2.3.2 Sensitive Vidicon Sensitive vidicon cameras (Ref. 6) use a vidicon having a slightly mont sensitive target surface. usually achieved by theincaily varying the corposition of the anthony trisulfide.

These vidi6ons ;re sersitive dowr. to 0.05 fc of faceplate illumination ano may be called the first or least sensitive of LLL TV cameras. In most ir. stances they are rhysically identical to a daylight camera and exhibit the same characteristics. like the standard vidicon camera, senst-tive vidicons are susceptible to some target damage if esposed to a very bright light or focused on a high-rontrast scene for too long. They also en%fbit picture smear,aten focused on a moving scene and generally tend to have a shorter life than standard ridicons..

2.3.3 Silicon-Olode Viditon The silicon-diode (SD) vidicon (Refs. 5. 6. 7. 9) has a special target element consisting of several hundred thousand discrete light-sensitive diodes. The SD vidicon is about ID times more sensitive than a conver.tlonal antimory trisulfide vidicon and therefore ca.: operate down to approximately 0.01 fc of faceplate illumination, equivalent to twilight condittors.

Many 5D vidicons display blenishes or white soots at the monitor; thesa are due to the failure of some of the diodes to become light sensitive during the manufacturing process. The ultimate price of SD cameras is determined by the number, location, and size of blemishes they transmit. Generally 50 vidicon cameras are more expensive than antimony trisulfide cameras. SD came'.

41sr may suffer f rom blooming effects ceased when the light hitting a particular diode also sensitizes the adjacent diodes en the Silicon wafer. A newer " low bloom" $D vidicon has reduced ttis problem to the point where i' is no longer of concern to the security user.

There are definite advantages in using a SD vidicon camera in place of a sensitive vidicon camera or a daylight camera. First. SD cameras c.n operate under reduced lighting conditions with their spectral response extending into the high red and near infrared regions. Second, they are virtually impervious to target burn when exposed to bright light. It is possible to Doint the camera at the sun without causing permanent damage to the SD vidicon. an impossibility with the dayilght or sensitive vidicon camera. Third, the 50 vidicon camera exhibits lower lag charac-teristics than does a vidicon camera, resulting in less picture smear at the nonitor when viewing a moving scene. Fourth, an SD vidicon tends to have a longer life espectancy than the regular daylight vidicon. Fifth, the SD vidicon camera has good resolution, although generally not as high as an antimony trisulfide vidicon.

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2.3.4 In_tensified Vidict*n The intensified vioicon (IV) ca gra (Ref s. 3. 6. 7. I",) represents the third class o' LLt TV cameras non co'untrcially available. The camera uses a6 the light-sensing elcarnt an anttmony trisulfide (daylight) vidtton with a fiber optic faustate and f ror' one to three s* ages of **aor inte'..titcatica just prior to the vidicon. The image entensifier acts as a light Pipitfier. with tne lumie.ous gain depen ent on the n rter of stages c8 tmage inte mtfiers cascaded 49 ether. A d

u sis.gle stage image intenstfier will provide a f uertnaxe gain of appros smately 50. The second and third stages will eact. provide a luminance gain of 20. Thus a two 6tage intenstiled vidicon (1 V) will be 50 20 = 1000 times n' ore sensitive than a waylight <tdtcon a e a three-stage intenstfled vi$ icon (!Y) will be 50 20 20 = 20.XC tines more sensitive. However, as each stage of image le.tenstri?e is added, the resolution

cf the camera cc renes. For a one stage IV. approntaately I M innes or resolution are lost; f:r each addittorJ1 stage of intensificattor, added, approsie.ately ISO lines of resolution are lost.

The intensif ted vidicon cameras are the mo.* seesttive and generally tee post espensive of the three classes of L*L TV surveillance cameras. A ::re-stage IV carera can operate under illunt.

nation levels of the f all moon (10 ' fc), an I;V ca e a can operate a der corwtittors of tha r

quarter moon (10-8 fc), and an ! ?V camera can onerate wer starlight conditions of the night sky (10- fc).

Intensified vidicon cameras operate ere ef fectt.ely in the yellow-blue region of the visible light spectrum. Therefore, test results are obtaiced.een they are useJ with light sources that operate in this region, e.g.. Sodium vapor la w s.

Since intensified vioicon cameras use en antimore trisulfide vidicon as a light sensing element. they exhibit the same interent weaknesses as a daylight cacera. These are target burn when espo*ed to high intensity light. tarr,et burn-te ven esposed to s scere high in contrest for an entended pertoo of time, and picture 149 on moving scenes.

2.3.5 Silicon Intensified Targes and Ir.+ensified 5411:en Intensified f.orlet Tubes The silicen intensified target (SIT) tube (Refs. 3. 7) is basically an 50 vidicon with a one-stage image intensifier completely (catained wit'.M a single glass er4velope. It is about 500 times more sensttive than a dayll*j t tidiCon camera, but not q,t:e 45 sensitive 45 an !!V.

h The tar < jet is subject to blemishes as in the 50 vidic r..

Also bright lights in the viewed scene can be a problem since the automatic brightness contr:* used to control blooming tevids to reduce l

the faceplate illumination, which causes a snore than estrage loss of background Contrast. Recent developments in $1T tubes have greatly reduced mar.y cf these light control problems. The SIT tube camera is cheaper than the I;V camera for cor 9ercial LLL TV applications, with additional savings realized in maintenance costs.

.Resolution is the line-producing capability of the ca era, it is cee of several electrcnic features by which TV cameras can be compared. Horizvtal resolution is defined as the meninum l

number of vertical black and white bars that can te resolved in 3/4 of the raster width. The j

higher the nunber of lines the sharper the image. T*e raster is the cattern of illuminated horizontal scanning lines formed on a television cat cce ray tube wren no signal is being i

received.

(

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The intensif >ed silicon intenstf ted target (151T) cawra uses a 5!T light-se%f g device that is connected to an image intensifier by fiber optics. It is about 15.000 tiv.es ricre senst-ttve than a daylight vidicon camera and recently has been replacing IN cameras. The reliability

of the ISIT helps offset its high tr.itial purchase price. and it eshibits the same characteristics as an 50 vidicon. Although espefisive.151T caneras a e less empensive than IN cameras. Unlike the Sli tube, the 151T tube consists of two glass v)cuum envelopes.

2.3.6 Solic. State Television Cameras The solid state televisica camera (Refs. 7. 11. 12. 13. 14) represents tae newest form of CCTV camera available on the comerstel market. The lignt-sensing element is solid state. consist-ing of a series of either charge-coupled devices (CCDs) or charge 1.ijection oevices (CIDs).

Solid-state cameras that have the sare sensitivity as 53 careras are available.

Because t>< light-sensing element is solid state. tre cameras are usually quite Sr.all, rugged. hig%1p reliable, portable, and easily blended into t'e surrounding environment. TLe sensor is neore sensitive in the naar infrared region. a'4 tnerefore the camera's performance is manimized under incandescent or sodium vapor lighting. Like 53 cameras, thev On operate under very high illunination levels and 10 not suf fer f rom scece burn-in. Solid-state cameras do not presently have the hortiontal and vertical resolution of other cameras, but wten used on a 9 inch monitor. the resolution is adequate for certain types of surveillance work. The apparect image uality of solid-state cameras is quite good across t*e critire raster display. Solid-state caneras cost between $2.000 and $4.000. but tae price s*culd decrease as soon as the mnufacturers go into f ull production.**

2.3.7 Second Generation 13 age Intensifiers Currently available on the comercial rarket are *.*e second generation of image letensifiers, which use microchannel plates. These trage intensif tees offer considerahlt advantage in size since they can produce the sane gain as a tnree-stage traje intensifier in a fraction of the

?-ngth. However. the channel multiplier's intensifiers

ave poorer resolution. Presently, they are riuch more expensive than the firs *. generation intenstfiers, tut as their usage increases. the price may decrease.

I 2.3.8 Dynamic Range I

l su veyed area aN tme eastrw light level in w%1th the

(

lioth the minimum light level of the r

[

camera will be placed are of concern to tha potential CC*V syste's user. Each camera needs to be able to operate f rom its point of maatrvn sensitivity. or stat.wri scene illu ination through the m

entire range of scene Itqht levels it will exoanter wp to fall sunlignt. or approntmately 10.000 fc. This is referred to as the dynamic ran;e (aef. 6) c' a ca-era. Since the upper level, or l

least sensitive level. is fined at 10.000 fc. the dyna-ic re ge arcreases as the sensittutty of the camera increases. Thus the dynamic range pecblem is m% greater for an IV camera t*in it is i

l Although ISIT. $17. and 50 cameras tend to exhibit >Ter rettability than their antimny trisulfide counterparts. :5IT cameras are less reltatie thae. Sti cawras -hich in turn are less reliable than 50 cameras.

It is espected that late 1 M., rices will be under $1.500.

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for a standard vidicon camera. The dynamic range problem is so'ved by controlling the Jmount of light reachirg the light-sensing element. Most camera manufacturers control the amount of light reaching the trd1 ping device with either an automatic tris

ccatrol or a neutral density filter **

or a combination of both. This is usually autonated by rcritoring the level of the video signal and using it to control a motorized lets in the lens or to erive an actuator that inserts a neutral density filter between the lees output and the tragtng device. Present techr.lques use the combination of a neutral density spot lens with an automatic iris.

2.3.9 pe_ solution and Frequen< y Bandwidth In addition to sensing the illumination from a viewed scene - a two-dimensional pattern of Ilgnt and dark - the TV camera must convert the light into an electrical sideo signal. This video signal consists of an analog signal orto which timing pulses Live teen superimposed. In the TV conitar. the sideo signal is converted into a repiadaction of the original scene.

In order that the human eye can perceive continuit/ of motion in the transmitted stene, complete pictu es or " frames" must be transmitted at a suitable rate. Broadcast television has r

agreed upon a "f rame frequency" transmission of 30 complete pictures per second from the camra.

However. CCTV camera manufacturers are under no obligation to adhere to this standard, although comparable rates have been generally adopted, it can sonetimes be advantageous to the user to verify that the CCTV camera he selects adheres to the standards used in broadcasting in order to be asle to use standard receivers. moniters. etc.. as availlary equipment. Broadcasting standards for CCTV cameras are given in Reference 16.

The amount of picture deta'l a viewer can resolve in a vertical direction is determined by the number of scanning lines that make up the raster. The amount of detail a viewer can resolve in the horizontal direction is primarily determined by the resolving power of the vidicon and the band.idth of tPe camera's video ampilf ter. This is referred to as the frequency bandwidth of the system. Broadcast television has adopted a standard cameea transmission of $25 scanning lines per frame wi*h a bandwidth of atout 4.5 MHz. Either the frequency bandwidth or the number of scanntag lines ray need to be in:rejsed to obtain the detail required for some special applica-tions such as personnel identification. For ea4Tple, dayltght vidicon Cueras Can be purchased that transmit aeywhere from $25 scanning lines per frame un to 1225 scanning lines per frame and vary in bandwidtn from 4.5 MHz to 30 MH2.

$1milar specifications are available for all til camera except the new solid-sta;e cameras.*** The broadcast TV standards are a compromise involving econo'ics. technology and picture quality, and, because their use minimizes interface and espansion croblems. most users of CCTV systems stay with the broadcast standards.

TV systems generally use one of two types of horizontal scanning schemes: non-interlace scanning and interlace scanning (Ref. 8). $1nce all broadcasting of TV programs is done according

.The tris is a diaphragm having a group of overlapping bla:es ti n open and close to vary the

.. diameter of tw aperture at the center of the lens.

A neu'.ral deesity filter is a screen or dyed gelatin or glass used for diminishing the

.ntensity of light without changing the relative brightness of colors.

One of the tetter solid-state cameras currently available comercia'ly transmits 190 scanning lines per f ra e and has a bandwidth of about 1.4 MHz. As the technology improves in this area so will the resolutten capatallity.

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d to an estabilshed standard, the images are formed in a precise manner. The horizontal lines that nele up the TV raster are traced by an electronic beam that scans the face of the cathode ray tute in a predetermined pattern. The beam starts at the upper lef t corr.er of the tube, traces a single line to the right. Shuts off automatically while returning to the lef t side of the tube.

and then traces the nest line. When the beam firally reaches the lower right corner of tae tube, it automatically shuts of f and returns to the upper lef t corner to begin again. In non-interlace or randum scanning. the horizontal scan lines for any vertical deflection *fcle are randomly spaced with regard to the previous cycle (Re'. 8).

Interlace scanning is used to incresse the vertical resciution and reduce flickering of the CCIW systst without decreasing horitontal resciution or requiring additional bandwidth. With interlace scanning toe beam traces the odd.nurtered horizontal lines on its first vertical deflection cycle and on the second vertical deflection cycle traces the even bortiontal lines, for a 2:1 interlace ratto. In 2:1 interlace 5:anning, each completed vertical deflection cycle is called a fleid snd two fields make up a fra e.

Broadcast standards call for 50 vertical fleids or 30 f rsres in one second with 525 horizontal lir.es per f rere. Interlace scanning is generally used in CCTV systees to obtain mantrum monitor picture stability and enhance video tape recording and picture quality (Refs. 8.15.11).

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3.

LISTRIEUTION SYSTEM Selecting the proper video distribution and control system may prove to be the most demanding and expenst.e decision in the selectiore of CCTV systems. The decision must involve not cnly the transmission of tre video signals to the monitor, but also, in soaie configurations, the transmis-slon of control signals from the central station to i5e camera. par / tilt units. lights, or camera environmental houslog. This chapter will discuss some of the various video transmission and centrol techniques available and their constraints.

3.1 Video Transmission Trere are several options available to the user of CCTV systems for transmitting video signals from the TV camera to the mn iltor. These are transmission at video frequency through coastal cable or balanceJ tel? phone lines, at radio freqsency (Rf) through coaalal cable or free The space, at ultra high frequency through free space, or via an infrared (IR) optical link.

final selection is based upon the 1 pe of envirorrient in w'.ich the system will be installed and 3

t'.e cost.

Because the transmission of video signals via coaxial cable is most comnonly used for CCTV applications. it is discussed here in greater detail. The use of coesial cable tas some definite advantages over the other methods; e.g.. It allows iptimum picture quality to tw transferred because the full aijeo bandwidth can be transmitted, it produces minimum transmission lostes because the signals are in the lowest possible frequency band, and it has the lowest supplemental equipment costs. The amplified video signal from the camera is best delivered by a 75-oM coastal cable unbalanced to Tround. This cable should te terminated in its characteristic impedance in If the order to eliminate reflections ar4 to transmit the maximum video signal to the rt elver.

cable is not matched properly. the reflected energy will cause " ghosts" to appear on the mcnitor.

Therefore, if more than one monitor is to be used per camera. the cable frms the camera should be connected by a technique called "loopt..p through" to a series of monitors having a bridging input, with the last unit terminated in a 75 ohm load (Refs. 8.18.19).

If the user desires to send a single video output from ore camera to several rer.ately located monitors. he can use a video distribution amplifier that provides isolation between the input and output signals and also between the individual ou'. puts. Thus disturbances on ore output line are not coupled to the other lines. Each output is treated as a separate video system and is termi-nated by a 75-ohm load. The vidco distribution ampitfier Can also be used at the Camera end to feed video signals from a single camera to several remote equalizing ampitfiers that have frequency and phase characteristics complementary to those of the coaxial cable (Refs. 8. 19. 20, 21).

Sometimes it is desirable to have the capability of switching between video ignals from various cameras to a single monitor. This is accor911shed with a device known as a terminating video switcher. which terminates 15e unused video signals trto 75-ohm loads while transmitting the chosen video signal to the mnnitar. This unit can be controlled either manually or automati-cally. If automatit. It is 6nown as a video sequencer.

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The mailmws distance a video signal can be transmitted with little resolucloi loss via a meJium size coastal cable is about 2000 feet under ideal conditions. In order to transmit greater distances, broadband video arolifiers are needed.

Although c04alal Cable provides escellent shleiding characteriltics against high-frequency electromagnetic fields, low-frequency fields produced of switching trJosients in parallal lines may penetrlte the shleid and produce interference (RPf.19). When transmitting videw signals long distances, the unbalanced video signal ray be cor.verted to a balanced signal an$ transmitted via a shielded pair of wires, which will cancel out low-frequency fleids. Cable aglifiers make It possible to transmit ielevision signals with a mantrui bandwidth of 16 MHz (Ref. 22). - Through careful selection of the cabling used and careful installation and adjustment of the equipment, monochrune installations of up to 25 miles can be made. The restrictions and fleatbility on raalmum transmission distances are dictated by the following (Ref. 18):

1.

Bandwidth requirement: the narrower the required bandwidth, the greater the distance the video signal can te transmitted.

2.

Size and type of cable: using smaller gauge wire or changing from sclid to stranded wire in the same transmission r n reduces the raatmum transmitted diaance since greater u

equallration by the line amplifiers is required. which reduces the maalewn power output.

3.

Cleanliness of the line: !arge nw-ber of cable splices, bridge taps, switching, or coueling capacitors or inductors in tae line all reduce ite transmission distance.

4.

Enviromrntal conditions: RF inte.-ference from outside sources has a profound effect on reducing the transmission length. The transmission.ength ray also very on lines exposed to large tenperature fluctuations.

5.

Grounding: good grounding at both ends of t:e run is imperative in preventing ground loops.

6.

Quality of the line: buried cable. shielding. etc., all increase the transmission distance.

Another method used for transmitting video signals is redulating an RF carrier signal with the video signal and transmitting it via a coazial cable er free space. This transmission approact is generally used. hen several separate video signals need to be transmitted a long distance to one terminal point. The separate signals can be eultiplened onto the single RF carrier and transmitted via a single cable. The cost of the modulators and demodulators used at either end may te high with this approach. However, the cost is sonemhat offset by the savings in Ca' ale and labor and having the capability of transmitting up to 30 separate video sources via ore cable or transmitter. hhei the video signals are transmitted via free space using an RF carrier. tf.?y travel line of sight from point to point and require a Feceral Comunications Comission (FCC) license. The use of amplifier and repe:ter stations can entend the range of free-space trans-mission, but may prove to be very expensive to initiate (Refs. 8. 19, 23).

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A relatively recent development in eldeo transmission is using a video-signal-modulated IR light beam. Its constraints are similar to RF free space transsission. but the equipreet is much less espensive and an FCC license is not reqvfred. Presently, optical IR transmission has a maximum range of about 3000 feet. This distance may te further limited by such envirormental conditions as rain or fog. Unfortunately, an optical link can transmit or.ly a single video l

signal at a tire. Care must be taken to prevent streng lights from entering the receiver and causing hum bars to appear in the raster. Care is also required to keep the lenses of tee transmitter snd receiver cleared. Under certain envirorrents tre optical link has sone advan.

tages not found with coanf al cable. Aa optical link permits video transmission across streets.

high=ays, parsing lots. and railroad yards where cable installattan may be difficult eM costly.

Also. since the equipment is ligttmeight and easily aligred, it can be set up or moved :;.ickly.

Mirrors sortatires are used to transr.it the optic.al If nk around corners but they will atteauate the signal from 40 to 50%. A preferred relay method is to use an optical receiver-tran;ritter, which receives. empilfles. retransmits, and redirects the signal to the end receiver. Per an optical link is placed out of doors in a cool envirorwxnt. the lenses tend to fog over 6nless the units are equipped with heaters located tehind or in the lenses. This option is offered by most manufacturers.

3.2 Control Sicnal Transmission In addition to having a methed of transmitting the video signal from the camera to tPe receiver, it ray be necessary to provide a rethod of transmitting control signals from the monitor end or control station to the camera 13 cation. Depending on the type of CCTV system and its location, the user may have to provide sigtels to control such devices as pan / tilt units.

room lenses. lights. video switches. tape recorders. filter asseetties, heating, coolirg, and windshield wiper units in the envirorrental housing of the camera, att even personnel and vehicle access gates. Power normally is supplied at the site where the canera is located. Previously, if a central station video tape recceder was connected to several careras, it had to provide the cameras with horizontal and vertical drive signals, which had to be transmitted to the camera site. However. this is no longer true, for cameras at the remote site can teve their hortzental electrical drive signals locked together.

Thus the complemi'y of the CCTV system determines the amount of control signal transmission needed. Soretimes this requirement can be reduced through careful planning. For example, a master synchrontalog generator located at the camera site can provide the prt'per synchroniting signals for several cameras connected to a corrion central station where a syrchronous systee is desired. This elirinates the need for transmitting signals from the central station to tre camera sites. Also, an automatic sequenW can be used to switch from camera to camera. hSere central station control is desired to control remote functions, the same techniques used fer transmitting video signals to the station can be used in reverse. There are clso avallante digital techniques in which control signals can be multiplened over a si wis pair of mires in order to control up to 20 different operations at a remote site (Defs. 19. 20, 21, 24, 25).

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If the user plans on using and insta111ng cable for the video and contrel signal transmis-sion System there are some basic Do's and Don'ts used by industry to follow. Ilsted in Ref-erence 8:

00 use connector kits for all video cable splices.

D0 use lugs on all centrol wire terminations.

00 solder all cornections properly.

DO tape til outdoor spilces securely to protect them from moisture.

D0 use messengers to support aerial cable runs.

DO use proper grounding tecnniqas, e.g.-

a.

short Seound leads - 20 foot maximum b.

good cor sections by soldering where possible, scraping water pipes before securing, and makt.g g od mechanical joints.

D0 test all grounds befcr. use.

DON'T place video cables ir a conduit with alternating current lines.

DON'T hardwire video cable spit:es.

DON't directly bury video cable, but place it in conduit.

DON'T use acid core solder on connections.

CON'T place cables near steam pipes, heating ducts. and other heat sources.

00*a'T place cables over edges or near movir.g objects that could wear away the insulation.

DON'T spilte the cable in the middle of an aerial run.

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4.

CLO5tD CIRCUIT TELEVISION MDMITORS 4.1 Technica! Considerations The TV ronttor is the end point or readout device for the CCTV systen. The quality of the picture viewed is determined by the contrast ratio and the resolution capabilities of the conitor.

TV camera, an1 video transmission system (Ref. 8). Most creriercially available monitors are standardized to provide 525 scanning lines per frame (2:1 interlace) at about 8 MHz bandwidth.

In specifying the resolution capability of their scnitcrs the manufacturers may use such tefTis as 800-Ilne horizontal resolution at the center and 650-line hortiontal resolution at the corners.

These resolution teres are based on the reoer of lines that can te seen on the Electronic Industries Association (EIA) resolution test chart discsssed in Sectica 8.3.4 (Refs.15.17).

The type of scene to be viewed dstermines the resolution needed by the camera and monitor.

The bandwidth or resolution of tt.e monitor should match that of the cacera output to provide the best detail at the rost economic price. Data transmission and signature or personnel verifica-it is tion systems nay require greater resolution than do normt ares surveillence scenes, possible to parchase monitors that have, for examle.1225 hortrontal scanning lines per frame and a 30 MHz video bandwidth. These moniters can be effectively used only if the remainder of the CCTV sys*.em has equivalent specifications.

All monitors need to be capable of reproducing all 10 shades of gray found on the CIA resolution test chart and should conform to applicable EIA standards (Pefs.17, 27).

4.2 Control Room Considerations Once the user determines the resolution requirertents, he rwst then consider control room layout (Ref. 8) t. decide or. the monitor's site and the viewing distance and viewing angle to the The TV industry has found that, for optimum viewing, the namirum vertical viewing observer.

angle between the observer and 'he e4nitor is 30 degrees. Tests perforred by industry on vary'ing the site of monitors have shown that the raaimum and minimum distances given in Table I provide Howe er, actual distances ray vary depending on the type the best detail to the average viewer.

of scene viewed, the monitor observer. Ilghting condition at both the scece and control room.

The reading of documents or identification cards woulo probably require the ob' server to be etc.

closer to the monito-than the minimum viewing distances recorrended. For some sury.11ance type applications, distances greater than the recor:4 ended ramir.um viading distance may be saf tsfactory.

In addition. the f arther the observer is seated f rom the centerline amis percendicular to the picture tube, the greater the amount of image distortion he experiences. For this reason, a maximum hortrontal angle of +45' from the center axis is recorynended for viewing without objec-tionable distortion. lihen it j$ r,eCes53ry to monitor W scenes with no distortion. the maximum i

horizontal angle shocId be reduced to 130'.

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TABLE 1 - MAK! MUM A!.0 MINIKh DISTA*4CE5 FOR LETAILED OBSERVATION Stie of Maximum Viewing Mininum itewing iv Tube Distance Distance f riches feet incnes feet t rd.es 9

7 0

3 0

12 10 0

3 4

14 12 0

3 7

17 14 9

3 9

la 16 11 3

10 21 19 0

4 10 23 19 4

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VIDED TAPE RECORDERS 5.1 Ceneral e

Video tape recorder fvT?.) equipment *Ref. 8) greatly entends the capabilities of a CCTV system tf providing a medh.:n whereby information displayed on a TV ronttor may be saved for replay at a later time. VTRs can be used by security personnel to record security frcidents.

train guard personnel en tre prepar procedures to be followed under various situations, and maintain a record of the varicus areas under TV surveillaace, in addition, magnetic tape has sore distinct advantages over flin recording. Some of these are:

I 1.

The video tape does nut have to be processed, but can be played back as soon as it is rewound; S.

The same machir.e used to record the infot4 tion is used tt* play it back; 3.

Tte magnetic tape can be erased and reused several times; 4.

5cond may be recorded on the same tape at the sare time the video is recorded er say be added later.

It 15 pmiele to switch ssveral creras into a single time-lapse VTR to riaintain a record of all the vi:=2d scer.es on a single tape. This reduces tne cost for video tapes anJ still f

~

provides a record for later viewing. However, because tire-lapse VTRs cut the number of frames

~ viewed per scene and constantly shif t from scene to scene, they are not recorriended for use with CCTV systems used for security. Personnel reviewing the tire-lapse recordings becore easily fatigued from having to concentrate cn several changing scenes, each having only a few fra es of l

infor.ation on them, and consequently derive very little useful infomation frose them. This is

{

especially true if a large number of cameras are being switched into a time-lapse VIR. These problems can be c'fset sornewhat by using newer typ(s of tire-lapse VIR tnat.can be switched k

remotely from time-lapse to real-time recording durino a security incident.

f 5.2 Types and Stres Availability of VTR types and sizes (Refs. 28, 29. 30) is a factor in the equipment selec-tion process. Two bas c types cf VTRs are available: the "quadruplex" and the "hel' cal scan "

The quadruplex is cominly used by TV stations for producing high-quality tapes, but the recorders cust between $20,000 and $100.000. Helical scan reccrJers, costing from $2,000, are mre than acceptable for CCTV systems used in sccurity applications. They are generally portable ar.d easy to operate, and they produce tapes that are interchangeable with similar crand models.

18 A

VTR$ core in var ;ous sizes depending on the width cf tape used. The wider the tape, the rcre infornation that can be stored and the higher the 44ality of recording. For nest security applications, either a 1/2-inch. 3/4-inch, or 1-inch tape is acceptable. A 1 inch tape provides high-quality reproductions, both in color and black and weite. Honever, there is a noticeable color degradation that occurs Juring tne editing process er in reproduc*.'en of the tape. The system is an encellent one f or black and white reproductices. A J/4-inch video tape. usually used in a cassette configuration, will produce high-quality color and black and white reproduc-tions. But. li6e the 1-inch tape, color degradation occ.rs during editing. Also, it is not acceptable as a master tape used to eproduce other colce tapes. Being in the cassette form, the 3/4-inch tape requires less maintenance than the 1-inch tape. The 1/2-inch videotare in a cassette config6 ration is best used for black and white re:roduction and for portable wor 5.3 Maintenacce Most proble-ms with VTRs are cassed by maintenance fa*.t:rs (Refs. 8. 3G}. such as not 6eeping the recording and playback heads properly cleaned. The teacs. guide, and head des, need to be thoroughly cleaned with a econnendec cleaning solution $stn as ethyl alcohol at lea:t once a week, depending on use. to ersure long arJ trouble-free operation of the VTR. If the VTR is not lept clean, tre life of the videotape and the quality cf the picture prod 6ccd are substantially reduc ed.

In the operating area. It is reco,nended that cre sters not snole er eat food near the VTR. as any particles f alling on the surface of the tape will cause a separation between the read and tape. which in turn causes a loss in stgent level.

The life of the video tape is also inflarnced by tre net %ods used in handling and storing the tape. Each time a ter-is handled, nil and grease are transferred to the tspe from the hand, later attra-ting dust in the atr osptere. Loading the tape ento the machine just prior ta its being used and handling 'he tape as little as possible will extend the life of videotape. In handling the tape. It is reco rended that operators be care'al not to damage the edget or scratch the surface. In winding.he tape, care is needed to ensu e trat Inose windir.gs and cinching of r

the tape do not result either from c;erator error or fro? t'e way the nachine transport handles tre tape. Fast starts and stops can cause poor packing, es;ecially if the trales on the rects do not operate evenly. It is advisable that video ta;es te stored in a low hunidity environrent.

Since high humidity causes tape breakage. In practice tre ideal ervironrent is 50t relative huridity at a temperature of 20'C.

Storing tapes on their edge rather than flat and haidling the reels care'ully without pinching tre sides together will also f elp prevent edge dar. age.

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e 6.

PAN / TILT UN!!$

Pan and tilt units (Refs. 5. 8) allow the camera to be positioned toward the area of interest and to view all portions of the scene with good resolution using a medium-field-of-view lens. Panning means moving the camera f rom side to side. Tilting means moving the camera up or The pan / tilt positions may be permanently fixed at the time of installation. or they may dows be recotely controlled.

Remote control pan / tilt units are used when the carera sus *. be pointed in different direc-tions at dif ferent times or when a large area needs to te surveyed. The remotely controlled pan / tilt units have electric retors and gears used to reptsition the camera's field of view at Limit switches that are mechanically activated by the position of the unit any given time.

control the fleid of scan. These Itmit switches are mechanically adjustable so that varytng fields of scan rwy be set.

Two variations of the norsal recotely controlled pan / tilt units are available:

1.

A remotely contro1Ied pan / tilt with or without autoscan.

An automatic scan that continuously scans a preset aret. but has no remote tilt control.

2.

Some automatic scan units have an override switch that 411cus the operator to remotely control the pan *t.it.

for most security applicatic,ns, it is recomended that the auto-This is because a security incident could occur while the camera's matic scan not be used.

field of view 't positioned elsewhere and thus not be detected by the monitor operatcr.

Pan / tilt units are available in configurations cated from light duty to very heavy duty, with dust-proof, explosion-proof, or water-proof options, as required. When installing the uni's it is recommende<' that the installer verify that the unit has freedom of rovement throughout the entire pan / tilt 5:an; that the cablei are long enough and dresseJ so that they are not pulled tightly, tangled, or worn by the movement of the camera; and that the camera's field of view does not become obstructed in any position of the scan.

$ ore disadvantages of using a pan /tfit unit are:

High raintenance costs because of the limited life of the electric motors gears limit 1.

switches. etc.,

High install 3 tion Costs beCause of the added cable runs required and the Cost of the 2.

j mechanism.

Inherent optical teaa zcnes because the carera cannot be looking at all places at one 3.

tire,and Increased operator response time required to ranipulate pan / tilt or roort contrails.

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=

7.

IMAGE MOT 1088 SENSORS In sorne CCTV installations, a monitor observer cannot provide constant observation because, for exarple, there are too many protected areas to allow efficieet ronitoring ty an observer.

For such installations. an image ration sensor can greatly increase the effectiveness of the CCM system. Motion sensors monitor tte video signal from a TV camera; when motfor occurs witt;9 the camera's field of view. the sensor initiates an audible and vist:1e alarm signal. Some sensor systems are incorporated in the TV monitor itself while others are a separate unit that vill, af ter sensing revement, switch the alared area video signal to a remote monitor. This gains the attention of the observer and allows him to imediately view, via the CCTV system the area where the alarm *eas generated. This corbination of CCTV system and video sensor allows imediate assessment oi' alarms and frees the observer for other duties when no activity is present (Ref. 31).

Various types of video sersors are comercially available. Some have small sensitized areas that can be positioned anywhere on the face of the sunitor. Movement that c&uses a 6% or greater light change in trese sensitized areas will generate an alarm sigral. Another type of system uses several hundred light-sensitive spots located throughout the camera's field of view to detect changes in Ifght level. Sone or all of these spots can te desensitized to allow for norir. ally moving objects in the field of view. e.g.. trees. A light change of rcre than 6% between frares in the sansitive area will cause an alarm signal to be generated. A third type places suction cups containing light-sensitive diodes over the area of the monitor where surveillance is desired. Changes in 'ight patterns under the shtion cup will te detected and will cause an alarm to be.nitiated. The disadva:1tages of this type of sensor is that the observer viewing the monitor cannot see behind the suction cup to deteraire the cause cf disturbance and the area cf sensitivity is relatively small.

Video motion sensors are usually quite sensitive and detect even small reverents within the camera's field of view. in many cans causing false alarms. The video cables cevecting the camera to the sensor are susceptible to electroragnet; interferer <e. which will also cause false alarms to occur. For these reascns rest installations use video sensors to monitor indoor areas where little or no movement occurs and where lighting conditio.is are kept constart. Even under these conditions. a higher false alam rate is emperienced than for other types cf volumetric alarms, but this is offset by the fact that the guard's response is merely to view the manitor to determine the cause of the alarm. Video rction sensors cost from 1500 per zone to about $1.500 per zone. the chea;er ones being tre suction cup sensors and the rcre expensive cres being the sensors that can ronitor all or any part of the viewed scene (Ref. 32).

Regulated power supplies should te used to power cameras used with action detector systems.

Without regulated power supplies, tcth tM vertical and horizontal size of ihe raster will thrink and expand with pMr surges and during the low-and high-voltage conditions tnat nor1 rally exist in a 24. hour period. These changes in raster size interrupt the video and cause false alarms.

21

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8.

AD0!!!ONAL C E IDrRATIONS ndhen designing a CCTV system there are factors other than TV hardware that need to be considered in order to obtain optimum system performance. Four such fact 2rs are lighting.

monitor observer performance cost of owr.ership ar.d testing. This chapter will d'scuss those factors to be considered in:

1.

Determining the adequacy of lighting in the area to be surveyed by the CCTV system.

2.

Mairtaining a CCTV system in operable condition.

3.

Testing the system to determine whether it meets minimum specifications and to locate potential problem areas. and 4

Obtaining optimum performance from the TV monitor observtr.

8.1 Lighting The minimun amount of lighting available to the CCTV camera determines the sensitivity of camera needed. However. as the sensitivity of the camera increases, so does the cost. The refore, it may tenefit the licensee to design a lighting system for the area to be surveysd that will always provide more illumination than the camera requires. In addition tn positioning the camera 50 that the entire scene can be viewed, care should be taken so that floodlights in the scer.e provide fcr maximum scene brightness and minimum glare. Floodlights should be placed and aimed to prevent a source of veiling glare to the camera. In general, this means positioning the floodlights so they are not directed at the camera lens. Lighting glare ir. tae camera's field of view will prevent detection of movement near or behind the glare source. Ir addition, glare can be a problem to cameras equipped with an automatic light-level circuit. If a high-level glare is near this type of cas ra's field of view, objects that are not as bright will be difficult to see.

e Once the location of the camera has been determined, it is necessary to determine the arrount of itght reflected toward the camera from the darkest creas of the scene. This is the product of the two factors I, and R; it can be determined directly by using a sptt brightness meter pointed '

directly at those areas in the viewed scene that have minimum brightness (e.g., doorways tunnels, and shaded areas) while in line with the TV camera. The measurernents are taken at a tice when lighting conditions are minimal. Care must be taken that the meter is on a direct line between the camera and t*e darkened area in order to prevent large errors in the meter reading. Once this product is known and the lens transmission efficiency and f-number have been determined, the minimum faceplate illumination available at the camera can be calculated using the formula given in Section 2.2; this determines the required sensitivity of a CCTV camera (Ref. 8).

If the user does not have a spot brightness meter available. Is can be obtained by taking light readings with a light meter. aCCording to the manufacturer's instructions in the darkest 22

a areas at the scene with the meter pointed toward the ca.9 era. Readings should be taken under the worst lighting conditions. R in most instances will have to be estimated. Three important characteristics of R are surface texture, i.e.. specular (mirrorlike) or rough; color, i.e...

bright or dark; and the distance and direction of the light source. Table 2 can be usea to provide an approximate value of R for typical scenes asstmiing a flat diffused illumination (not a point source) as Jn an overcast day or a Clear starlit night (Ref. 3). An average scene will

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provide an aurage light level with highlights. Also, the scene may cf.ange characteristics from time to time, g., an empty parking lot partially filling up with cars or snow falling on the ground. It can be seen that the user can greatly improve the ability to detect movement in the surveyed area by increasing the light available to the camera with backdrop! that are smooth and light in color.

TABLE 2 - RELATIVE SCENE REFLECiANCE VALUE5* (Ref. 3)

Scene Being Televised

% Reflectance Empty asphalt parking lot 5

Parkland area. trees, and grass 20 Red brick building 35 Unpainted concrete building 40 Parking lot with automobiles 40 Smooth surface aluminum building 65 Glass windows and walls 70 Snowy field with chain link fence 85

Courtesy of C0HU. Inc.. Electronics Division. San Diego. California.

Af ter the illumination levels are determined, the user will need to decide if the CCT'.'

camera is to be 'Jsed for detect lon purposes or identification purposes. If used for detection purposes. the camera is ordered according to the " usable spec" given by the manJfacturer. For identification purposes, the illumination at the vidicon will need to meet the " full spec" given by the manufacturer. If it is determined that more floodlights are required to achieve a desired illumination level, equations found in the "Illuminatir:g Engineering Society Lighting Handbook" can be used to determine the number of additional lights needed.

Another lighting factor to be considered is the effect of weather. Fog can cause a blinding effect on the camera such as that experienced by one driving through fog with the high headlight i

beams of the cur switched on. It may be advisable to turn off the lights near the camera in l

times of fog (Ref 4).

Since most CCTV camerss are more sensitive when operating in the IR portion of the light spectrum, improved CCTV performance can be obtained by providing lighting that is high in red content. Soditmi vapor lar.ps are high in red content, provide more lumens per watt, and have a short restrike time when corpared with such lighting systems as rercury vapor la@s (Ref. 8).

23

o A user is of ten f aced with the problem of deciding between increased lighting or increased carera sensitivity. Figure 3 can be used to determine whether an expensive LLL camera is sure cost ef fective than adding increased lighting in order to reduce the requirement for an LLL carera. An exar)le is given to show how the chart in Figure 3 may be us*d to deters.ine which route the user should take to obtain the optimiri camera and lighting cor.ditions for a particular applicattor. (Ref. 34).

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Assume a lot measuring 300 feet x 300 feet. or 90.00G nuare feet, is selected for : 1.CTV system. A cost benefit comparison is etide between an inexpensive camera that requires 0.05 fc of illumination at the faceplate and an expensive camera that reqJires 0.00005 fc. Both cameras will be mounted with a room lens having a speed of f:2.8 and a transmission efficiency. T. of 781. The scene is assumed to have a reflectance. R. of 201. By solving the equation in section 2.2 for !s the first camera is found to require a scere illumination of 10 fc. and the second an illumination of 0.01 fc. Figure 3 shows that 0.5 watt /sa f t is required for a mercury vapor lamp to produce an illumination of 10 fc. Therefore to properly light the 90. " 4.are foot lot for the inexpensive camera will require 45.000 watts of power.

24

Figure 3 also shows t:.at with a more expensive light source, filarent (or quartz-lodine).

only 0.0015 watt /sq f t of power is requ red to produce 0.01 fc of scene illeination. For the i

90.000 sq f t lot this amounts to a total power of 135 watts. Thus it appears that the cost savings in power requirements would more than justify the additional expense of the pore senst-tive camera (Ref. 33).

8.2 Cost of Ownership There are three factors that need to be considered in assembling a CCTV system. These factors are price, performance, and cost of ownership. The pential user usually considers all three factors in arriving at a buyirg decision. Sometimes subliminally. Unfortunately, m ny times these factors are not weighted equally. In fact. cost of ownership is of tentine ignored.

Between 75 and 85% of all maintenance costs of a basic CCTV system are due to the camera, and these in turn are due to required replacement of 18.3 light-sensing element

and image intensifiers.

Therefore, approximate cost-of-ownership figures over a 5-year period can be developed based on light sensor replacement costs for the various types of cameras. Examples are presented below for figuring the cost of ownership of the various camera types over a 5-year period. Prices of cameras and replacement parts are based on 1975 dollars and my very widely depending on the manu-facturer and model type. The purpose of the ;mample is to show the rethod of computing cost of ownership, to show the approximate increased cost of ownership over the original price of the carera, and to make the potential user more aware of this factor in asses 611rg a CCTV system (Ref. 7).

8.2.1 Dayli s t Vidicon Antimony trifulfide vidicon daylignt cameras generally cost between $200 and $o00. As discussed earlier. the antimony trisulfide vlaicon is subject to target burn if pointed at bright lights or left in ene position for too long a period of time. Thus, risapplication by the user can result in several vidicons being replaced in one year. In addition, the average antimony trisulfide vidicon will suffer a degradation in resolution over a two-year period even ur. der proper use. On the average, antimony trisulfide vidicons need to be replaced annually at an approximate cost of $75 per vidicon. Using these figures, the cost of owrership for a daylight vidicon camera can be computed for a 5-year period. As seen from Table 3. at the end of a 5-year period, the user has invested an additional 125% of the initial cost in cost of ownership. This does not include the cost of repairing and replacing parts in the event of any other problems that might develop with the camera systee.

8.2.2 Sensitive vidicone.

The initial ccst of a sensitive antimony trisulfide vidicon canera varies between $800 and

$950. Like the daylight vidicon camera, the sensitive vidicon nornelly has to be replaced annually in order to maintain high-quality TV pictures. A sensitive vidicon costs between $375 and $550. Assuming that the initial price of the camera was $800 and the replacement vidicon cost was $400, over a 5 year period the additional cost of ownership is 250% of the initial cost (see Table 3).

'It is possible to significantly extend the life of the nore expensive light-sensing elements that use filaments by specifying that the filaments be supplied fram regulated voltage supplies.

Many tube manuf acturers guarantee their tubes only when toey are coerated at their filanent voltage specifications.

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8.2.3 Silicon-Diode Vidicons Since the 50 carera is Goed quality 50 vidic >n careras range in price from $900 to $1.500.

Even though the 50 vidicon costs impervious to burn. the v'dicons need changing less frequently.

riore than conventional v.dicons, they last in rany cases f rom one to three years under continuous Thus, 50 cameras have between 8.760 and 26,280 hours0.00324 days 0.0778 hours 4.62963e-4 weeks 1.0654e-4 months of operation before having to te replaced.

The cost of ownership is calculated assuming a purchase price operation before th y are changed.

Table 3 shows that, over a 5 year of $1.200 and a 'aennial vidicon replacement costing $450.

period, the '.dditional cost of ownership is 751 of the purchase price.

8.2.4 Intensified Vidicons_

The price of intensified vidicons varies from $8.900 to $13,500. This price may or may not Some manufacturers use an autoratic f ris control as part of the auto-includt the lens system.

The matic beightness ccntrol subsystem; in this case the price generslly includes the tens.

prirary cost-of-ownership f actors for these cameras are the initial purchase price and frequency of replaccment of the image intensifier and vidicon. The image intensifier and vidicon for one,

two, or three-stage units are :sually an integral unit. The light-se wing element is an anti-mony trisulfide vidicon; therefore, although the amount of Ilght reachir<j the vidicon is con-trolled by the intensifier, the vidicon is susceptible to burn-in caused by leaving the camera A one-stage intensified vidicon costs about $1.325 for the focused too long on a fixed scene.

user to replace, and an IdV costs about $2,0LO to replace. Ass:ritng the user has a 1-year factory warranty on the intensif fer so that any failures occurring during the first year are repaired at no cost to him, the 5-year cost of ownership was calculated for both one-and two-From Table 3 it is seen that the additional cost cf ownership is 53 and 67% of stage cameras.

the original purchase price for one-and two-stage cameras, respectively.

8.2.5 Silicon Intensified Target Tube Cameras A sli camera can be purchased for about $6,000. Essentially it consists of an SD vidicon connected to a fiber optic image intensifier. The manufacturer now offers a 1-year complete The tube is rated for 2,000 hours0 days 0 hours 0 weeks 0 months Mean Time Eetween Failures (MTBF) based on acceler-warranty.

Limited field experience has shown ated life tests over a 2-year period of continuous operation.

Three levels of $1T tubes are the tube needs to be replaced approximately every 2 to 3 years.

Prices of the SIT tube range available, determined by the number of blemishes in the display.

In calculat-between $1.800 and $3,000 depending on the number, size, and location of blemishes.

ing cost of ownership over a 5-year period, it is assumed the SIT tube will have to be replaced Assuming the tube is replaced at a cost of $2.000 each time on a $6,000 initial every two years.

purchase price $1T camera, the cost of ownership is 67% above the initial price (see Table 3).

8.2.6 Intensified $111 con Intensified Target Tube Cameras An ISIT tube canera can be purchased by the user in. price range between $9.000 and $.2.000.

Two qualit.cs of tubes are available, rangieg in price between 13,300 and $3.800 each, depending This is a relatively new canera on the rarket.

on the mroer of blemishes in the viewed scene.

However, since the and MTBF figures based on industry emperience have yet to te rade available.

27

ISIT tube is the same as the SIT tute except for an auditional fiber optic image intensifier in the front end, the MIEF will probably be about the same. Assuming the camera is purchased for

$9.000 and the tubes are replaced every 1 1/2 years at a cost to the user of $3.300 each time.

the additional cost of ownership over a 5-year period is 110* of the initial purchase price (see Table 3).

8.2.7 Solid-state Cameras The new solid-state cameras presently cost about $2.000. They have the advantage that they Therefore, any additional cost are completely sulid state and do not need vidicon replacement.

of owr.ership over tte initial purchase price will be due to other factors in the CCTV system reqairing mainter.ance.

8.3 Testing and Maintenance Periodic testing and esamination of the CCTV system and each portion of the system is needed to ensure that the system will be available when most seeded and that it is performing to the Documenting results of the tests and examinations perfomed specified requirements of the user.

will allow the user to develop a nistory of operations that can be helpful in locating weak areas of the system.

8.3.1 Camrra Cach of the rechanical func* ions specified for each camera. i.e., tilt pan, room, and The test focus, needs to be tested at the start of each shif t when the instrument is in use.

should consist of operating each of these functions to the limits estabitshed at the tire of Visual observation of the limits of the field of view, corpared to purchase of the instrument.

that originally obtained, can be used to decide whether the instrument is responding properly.

Upon complettoo of each camera's test, the camera should te positioned so as to visually cover If the camera is encased in an environmental hcusing, the viewing glass the area to t,e surveyed.

to the housing should be cleaned as needed and any appurtenances (e.g., fans, windshield wipers.

heater) checked for proper operability in conjunction with the daily camera tests (Ref. 8).

Semiannually, the camera shoald be checked for horizontal center and corner resolution.

I This can be linearity, black and white streaking, gray adjustrent, and proper sec generation.

At the same done using the EIA resolution test chart (Figure 4), discussed in paragra)h 8.3.4.

time the vidicon should be checked for burn-in and burnt spots. If the camera cannot rett minimum reqairenents, corrective actions should be taken. Cameras used for surveying the outside perimeter should be tested at sore time during each year under all the enviror cental conditions If under certain peculiar to that location (bright sunlight. snow, rain, fog. dust, etc.).

environmental conditions the camera does not provide adequate surveillance of the sensitive

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areas. the problem should be logged the proper managenent notified, and corrective acticn This action can involve increasing the lighting, increasing the guard patrols during initiated.

j inclement weather, increasing the sensitivity of the carera, repairing or readjusting the system.

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8.3.2 Transmission System Sealannually, the tras.smission system needs to be inspected. Examination should include inspecting cables for wear and cable connectors for corrosion and testing the line amplifiers, sequence switchers, RF and IR transmitter / receivers, and isolation transformers against the manufacturer's specifications.

8.3.3 Television Monitor The assigned monitor operator of the TV system vill probably be the first to observe any deterioration in the resolution of the TV monitor. Any noticeable deterioration of resolution needs to be logged and rectified as soon as possible. If the surveillance console has the capability for transferring images from one video monitor to a separate larger monitor for blowup and better resolution, this function needs to be tested daily. The resolution of the monitor needs to be checked en a semiannual basis. This can be done at the same time as the semiannual inspection of the TV cameras using the EIA resolution test chart. In addition, a qualified TV maintenance person should simultaneously check out the varfous subceponents of the system to see that they meet manufacturer specifications.

8.3.4 Electronic Industries Association Resolution Test Chart In 1956 the E!A (Refs. 16, 17, 27) designed the EIA Resolution Chart to provide a sta9dard reference that could be used throughout the CCTV industry for measuring resolution of monochrome tesalston systems and as an aid in testing for streaking, ringing, interlace, shading, scannirg linearity, aspect ratio, ard gray scale reproduction (Figure 4).*

Reference 34 gives instruc-tions for using the chart as follows:

"This chart is 18x24 inches in area and is set up on an axis with the lens of the camera, in a vertical position, and at a distance that permits the lens to be zooned all the way out for a lang shot. The camera is then moved until the entire chart is visible in the TV mor* tor's underscanned position. The card should just fill the picture with the four corners and sides visible and the side arrows at the end of the picture. With the brightness and contra;t set for the best picture under good lighting, the resolution of the camera can be seen by viewing the vertical wedges. At the point where the lines seem to blend, the number shown gives the lines of resolution."

The vertical wedges measure the horizontal resolution, which can be converted to frequency i

l bandwidth by the for nula f=h where f = frequency bandwidth in megahertz N = indicated number on chart.

I Copies of the chart can be obtained from the Electronic Industries Association, 2001 Eye Street hW., hashington, D.C. 20005.

30

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Reference 34 cor.tinues:

"The small wedges in the corner circles reasure corner resolution. The three squares of vertical lines (labeled 200) are for checking horizontal lirearity.

I The four circles in the corner and the small ones at the centcr should be true r.unJ with good linearity. The black bars above and te.ow the gray scales are a

for checking black and white streiking. For the 10 steps of gray, adjastments shcald be made su tFat all.0 gray scales are seen. T*ie four diagonal lines com.ing f rort the center check *.be sync signa!. With randori interlace the lines will be jaggeJ; with 2:1 interlace the lines should be straight."

As ca1 be seen, a chart of this type quickly allows the user to make a dJtermination as to whether a CCTV system meets specifications or tas degraded significantly since the last test.

Recording the results of all tests helps the user of CCTV systers to deternine at a later date any degredation that may have occurred.

i 8.3.5 Videotape Videotape recordings are capable of being initiated by s*gnal frcri the central alarm station nr from an intrusion alarm in a vault or material access area. Operation cf the re:ording

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equipnent by signal from the control room needs to be tes*ed dall. At the time 16 test is

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made, video recording fre the area under surveillante shot.1d star *. Af ter a short period

( 6 minutes) the recording should be stopped manually and the playback mode tested. Playback should repr % e sne area under surveillance.

It is adelsable that the head, guides, and head drm s be thorcughly cleaned weekly with a recorsnended cleaning solution. To reduce maintenance problers, the VTR is best operated in a clean environeent at a ncminal temperature of 20*C and 50; humidity (Ref. 30).

8.3.6 Lighting Heasurments of the illumination may have to M made at least cnce a mnnth to ensure that the light level has not deteriorated below requirements. It is recorriended that naterial access areas and vital areas have a minimum illumination of 50 fc in the darkest portions. Measuremerts in these areas car be made with a light reter used according to the r.anufacturer's sta**

at.

ing procedure with readings taken at waist level. At the oerimeter fence line, the m required illumination la 0.2 fc measured in the dr.rkast areas. Neasurements are made with a light meter or incident illumination meter used according to the manufa:turer's instructic s in the darkest areas under worst lighting conditions. When the illuriination in any of these areas is found to be below specifications, steps need to be initiated to bring the level into confomity.

4 1

8.3.7 Porer Those CCTV systens used for surveillance of the perireter of protected areas and for cun.

trolling access of personnel into vital areas need to be equipped with an eight-Sour emergency power system that automatically takes over in the event the prirary pc.er system falls. CCTV systems that are used for responding to alarms or for the surveillance of personnel in raterial l

31 i

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k access areas need not be equipped alth a, emergency power system if security personnel are available to assume that function in the event of a power loss.

8.4 Obtafninu Optimum per_formante From Monitor Observers The most critica) element in obtaining eptimum performnce of a CCTV system is the human component or monitor observer. The optimum CCTV system installed is still limited by this huwn subsys teri.

Therefore, it is to the potential user's advantage to spend as muc*. time on planning for this subsystem as he does on any other compon,rnt of the CCTV system.

The hr.an kesources pesearch Offices reported the following results of tests consucted for determining optimum perforrance for monitor observers (Ref. 35):

1.

Brief rest periods (2 to 10 minutes) once every half hour maintain a hign level of perfornance.

l 2.

Watches of randomly irregular length are preferable to watches of regalar length.

3.

Random, brief, supervisory observation maintains a high level of performance.

l 4.

Relatively young monitor observers (mid-20s) are preferred to younger or older monito.-

i observers.

5.

Women t-ai to make better monitor observers than ren.

L 6.

The combination of high terrperature and high humidity adversely affects performan ce.

These guidelines can be helpful to the user of CCTV systems in setting up operating proce.

dares and physical qualifications for monitor observers. In addition, the following guidelines i

can be used for leproving the monitor observer's performance:

1.

On a non-routine basis, test the system by having sonecne walk through the camera's fleid of view.

2.

Provide 1 }e screen monitors onto wenich suspicious activity ap; earing on the smaller monitars can be switched.

3.

Limit to less than 16 the number of menitors for which any single monitor otserver is responsible.

4 Provide adequate training to the monitor observers on their respcnse to CCTV incM?nts, their use of the equioment (i.e., use of pa'i/ tilt and room lens, etc.),.nd their responsibility for maintaining as clear a CCTV presentation as po.sible.

32 1

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9.

PHYSICAL SECURIT USES Scurity personnel use CCTV systens for the survelliance of people in critical areas, for the monitoring of sensitive areas, for the identification of people entering secured areas, for assessing alarms in protected areas, as snation-detecting alar, systen.s. for training and updating of guards on their duties, and for tre visual recording of security incidents. This chapter will attempt to identify some of the more comon uses of CCTV systems in physical security and give suggested specifications for the various uses.

9.1 Exterior uses The Night 41sion Laboratory of the U.S. Ar'9y Electronics Comand conducted tests using a CCTV system in a dark remote e ivironrent to detemine its ati'ity to detect, recognize, and identify targets at various ranges (Ref. 36). The system ceasisted of an SD vidicon camera, an IR illuminator (used where natural lighting was insufficient), an RF transmitter and receiver, an 8-inch TV monitor and a control panel for controlling the iris focus, filter, and pan / tilt functions at each remote TV camera. Table 4 and Figures 5 ax 6 give the resaits of all the tests perfored. The ranges given are for military targets (e.g., individuals wearing black pajamas at night). The fiald of view of the cameras used was 20 degrees. Results of the Night Vision Laboratories test show that a ;roperly installed CCTV system can be higily effective in detecting individuals inside any unsathorized space even under adverse conditions. The -ecomen-dations in the fc11cwirg sections re;resera minime specifications that can te used in ordering and installing a CCTV system to be used in surveillance of a perimeter area.

TAEAE 4 - TARGET DETECTION. RECOGNITION. AND DENT:FICATION (Ref. 36)

!ay Night D

D Detect Recognize

Identify Cetect Recognize' Identify 0= vices t

s t

1 CCTV 71 E6 66 43 27 20

?.

REM 3TE ALARM SENSORS 85 59 0

53 28 0

3.

TV AND REMDTE ALARM SENSORS 86 83 52 73 67 45 ho. Oetected "O* F'C09'I'*d t Detected

ho. Presented % Recognized = No. Fresented Identified = g. Identified No p

l 4

S Recognize - A target was considered as tai.9 re:ognized i the operator had ened. Ini~ u'c.

to generally determine if it was a rian o :niN cr other sowing cbject.

Identify - A target was tv. Wed as b?ing identified if the cperator had eno.nh inft,r nation. to uriquely identify 3e man. e % 1. etc.

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=

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^'

a.

O via'ct<*

gg EPER$0NNEL leco 5 1200 h1200 r iioa M 1000

{h g too

no s soo soo 400 200 200 -

100 -

DE TECTION RECOGNITION IDENTIFICATION 5

400

$$ M

~

O via'c's tecat= '**<a z

htGHT Eh200

~

i h VEHICLE LIGHTS UNTAPED' h5 "

~ h-

. pep:ONNEL I

h B h

4 DE TE CTION RECOGNITION IDENTIFICATION FIGURE 5 - TARGET RkiGES (Ref. 36)

{_

DAY 1W l NIGHT.

1000 E 900 Eg soo no Em a

g soo 400 aoo 200 i

DE TECTf 0N RECOGNITION IDENTIFICATION FIGURE 6 - WATER TARGET RA.NGES (Pef. 36) 34

ae 9.l.1 Cameras Cameras should be so mounted and arranged that the entire zone surrounding the perimeter of the protected area is always within a camera's field of view. Where possible, cameras neef to be placed so that they are pointing parallel to the adjacent perireter of tt.e prctected area. This will lessen the chances of an intruder successfully bypassing the system by shining a bright light into the camera's lens and cause blooming to occur. TV caneras using 50 vidicons generally are better suited for outdoor applications than those using antirony trisulfide vidicons.

For adequate resolution, the camera needs to have the standard $25 scanning II.ws per frane (2:1 interlace) with a mininum frequency bandwidth of 9 MH2. Pan / tilt and motorized room lenses are generally not recommended for perimeter surveillance; they should be used only to position ae.d focus on a suspected activity. The Camera needs to be located so as to prevent or inhibit its being tampered with. Men located outdoors, the camera can be eqalpped with an er virorynental housino containing a windshield wiper, cooling fan, and heater, depending upon the environment.

9.1.2 Transmission Link All cable runs from tte car ra to the central gaard Station shosid be placed in dedicated e

grounded conduits w5en passtng through areas of high electromagnetic interference.. When travers!ng open security areas. the cables can be either buried under ground in conduits or strung overhead in messenger cables dedicated to CCTV systees.

If a microwave link or eptical IR link is used to transmit CCTV information across open security arcat, all cable runs to the receiver and transmitter need to be located within the -

protected areas for physical security. Lenses used on IR optical data links need to be equipped with heaters to prevent fogging. Mir ests should not be used as optical relays. The transmission system must be compatible with the came.. and monitor as far as fregtency bandwidth and signal-to-noise ratio are concerned.

9.l.3 Monitors For optimum monitoring of sensitive areas there needs to be at least one monitor for each zone under TV surveillance w'th no more than four careras being automatically sequenced into that monitor. Sequencing more tran four cameras ints a single monitor presents the viewer with more information than can be ass'nilated for adeq2 ate surveillance. The monitor needs to have a minimum of 525 scanning lines per frame (2:1 inteelace) end a 9 MHz bandwidth for adequate resolu-tion, it is recommended that the entire CCTV system have a minimum horizontal resolution of 700 Ifnes at the center of the ronttor and a mininum of 550 lines at the corners. As a general recommendatici, the resoluticn of the entire system should be sufficient to allow detection of humac movement within the zone under surveillince. The console operator must also have the capability of manually switc%f ng to any camera desired in case of suspicious activity.

For optimun viewing, the vertical viewing angle of the operatcr to the Penitor must be no more than 30*. the horizontal angle no mere than +30' from the center amis and the viewing distance between the maximum and minimum recors, ended in Table I for the size of the monitor used.

35

/

9.1.4 Video Tape Recorder If the CCTV system is to be equipped with a VTR. It should be so arranged that it can be manually or automatic 611y activated and switched to any camera. This is reconsnended so that a video record can be made of any incidents occurring in the surveyed area for later analysis or investigative purposes.

9.1.5 Lighting Lighting in the area under surveillance should be of sufficient intensity to allow detection of human movement anywhere in the surveyed zone under the most adverse environmental conditions for that location. Cameras must not be aimed in the direction of bright sunlight, nor should floodlamps be directed at the camera. TV detection can be improved by providing a backdrop high in color contrast with the surveyed area. Lighting at the contril console should not produce a glare in the observer's eye by reflecting from i he monitor.

9.2 Interior uses CCTV systens can be used for the surveillance of personnel in sensitive security areas and as on alarm systen for monitoring sensitive security areas. Secomendations on ordering and installing CCTV systems for interior use are given in the following sections.

9.2.1 Cameras Caneras need to be positioned to cover the entire area at all tires. The cameras should

~

have a minimum of 520 scanni.eg lines per frame (2:1 interlace) with a 7.5 MHz frequency bandwidth for adequate resolution. It is recorsnended that remotely controlled pan / tilt units and zoom lenses be used only to reposition the camera and zoom in on suspected security incidents. N to-matic scanning of the material access area is not recomended unless areas of high sensitivity are constantly in a camera's fleid of view.

9.2.2 Transmission Link The transmission system must have sufficient bandwidth and signal-to-noise ratio to be compatible with the cameras (Ref. 6). For good physical securit) it is recomrnended the transmis-sfon system be kept within the protected area or be physically protected by other means. Signal lines need to be shielded against electromagnetic radiation.

9.2.3 Monitors It is recomended that no more than four cameras be automatically sequenced into a single monitur. The monitor needs to be optimally located with respect to the observer (see Table 1).

The monitor needs to have a minimum of 525 scanning lines per frare (2:1 interlace) with a 7.5 MHz f requency bandwidth for adequate resolution. The overall CCTV system needs to have a minimum horizontal resolution of 600 lines at the center and 450 lines at time corners. Lighting at the control console needs to be directed so light glare is not reflected from the monitor screen to the observer's eye.

36

~-

9.2.4 Lighting The illumination level in sensitive security areas needs to be a minimum of S0 fc in the darkest area. Lamps can be positioned to avoid glare in the cameras. For CCTV systems incorpo.

rating an alarm sensor subcoriponent, it is recomended that the background in the fleid of view of the TV cameras provide high color contrast.

9.3 PersonnelIdentifica,tigi CCTV systems can be used for identification and authoritation of personnel desiring access into protected areas arj vital areas. However, when used for identification of personnel, higher overall Systna resolution is required in order to have enough facial detail to make an identifica.

tion. The criteria in the following sections can be used in ordering a CCTV system to be used for personnel identification.

9.3.1 Cameras The TV cameras need to be located in a tooth or passageway that can acconcodate only one person at a time. One camera should be placed to provide conplete coverage of the area. If identification for authortring entry of a person into a security area is to be established by comparing a picture badge with the individual's facial features, either a split image camera or separate cameras for the face and picture badge will be needed. The TV system used for pcrsonnel identification and picture badge comparison needs a c'nimum horitor.tal resolution of 800 lines at the center and 700 lines at the corners. The TV system used to survey the booth or passageway for packages or entra persons needs a mininum of 500 lines at the center and 400 lines at the corner.

9.3.2 Control Point It is recommended that the guard cons le operator and the control point be located in the same protected area. The booth or pasageway serving as the control point should be able to accom-modate only one person at a time. Access into the booth or exit f rom the booth to the security area can be remotely controlled from the guard console 50 that a person may enter the booth only whr.n it is not occupied and then only when an indicator at the guaed console thch s that the door to tto security area is closed. An intercom between the guard and the booth can enable the guard to give instructions to the person seeking entrance. The reconnended lighting for the bootn is 50 fc or more.

9.3.3 Monitors At the guard console, the comparison of the badge with the face can be made either with a split-screen monitor or with separate monitors. The image from the camera used for surveying the booth can be fed directly into a separate monitor or automatically seqJenced into the face monitor.

The number of scanning lines per frame must be the same as that of the camere, and the frequency 37 l

bandwidth of each monitor must be equal to or greater than that of the camera to which it is attached. It is recommended that the monitor used for personnel identification be no smaller than 12 inches, the console operator be located at the optimum viewing distance and direction from the monitors, and lighting at the control console be directed to avoid glare on the monitor screen.

9.3.4 Emergencies In the event of si:tsa failure, the guard r.eeds to have a metnod for bypassing the interlocks on the access doors and locally checking personnel entering the secured area. Also, for use in the event of an emergency, the door into the bocth on the non-sensitive side needs to be equipped with a manual release mechanism.

9.4 Assessment of Alarms Instead of physically responding, the guard force can use CCTV systems for remote assessment of alarms or evidence of intrusion in a protected area, an isolation zone, a material access area, or vital area. However, when used for remote assessment of a security incident, care must be taken to ensure proper installation and mainter.ance. Guidelines are given below to help ensure that the CCTV system installed is adequate for remote assessment of alarus. It is desir.

able that such a system include the capability of switching to a VTR.

9.4.1 Cameras TV cameras need to be capable of covering tre entire alarmed area. This can be through the It is recom-proper combination of pan / tilt units, automatic :oon lenses, and multiple cameras.

mented, however, that pan / tilt units and Zoom leeses be used only to focus in on a security incident and not to provide complete area covera;e. The is camera needs to have a minimum of

$25 lines per frame (2:1 interlace) with a 10 Mh2 bandwidth.

9.4.2 Transmission Link The transmission system's bandwidth and sig*.al-to-noise ratto needs to be compatibic with the camera and monitor specifications. It is reconnended that the transmission system be located in protected areas or otherwise protected by line sJperVision and/or other physical security measures.

9.4.3 Ponitors The TV monitor needs to be compatible with the camera in number of scanning lines and frequency bandwidth. A minimum resolution of 600 lines at the center and 700 lines at the corners is recommended. The console operator needs to be located for optimum viewing of the monitor and, if viewing a 12 inch or smaller monitor, must have t?e capability of switching to a larger monitor.

Monitors can be equipped with non-reflective glass to reduce glare from lighting in the central alarm station.

36

9.4.4 Lighting Lighting needs to be at a minimum of 9.2 tc outdoors 'n darkest areas and 50 fc indoors.

?

The cameras and light need to be positioned so as to pro uce minimum glare. The lights in the control room need to be directed to avoid a glare f rori J e rionitor screen to the cbserver. In the event of system malfunction, poor lighting, or advers= environmental cor.itions, guards need to be sent to respond and evaluate the security incident.

l l

39 l

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RIFERENCES 1.

" Lens Selection Guide." VCP2-5004, General Electric Corcany. Electronics Park. Syracuse New York 13201. August 1971.

2.

"The Focal Encyclopedia of Photography." The MacMillan Company. New York. New York. April 1 %3.

3.

4.

Howard A. Co:hran. " Lighting for Closed-Circuit TV Surveillance," Lighting Design & 4 plica-tion. March 1974, pp. 47-49.

5.

CCTV Systems Made Easy." SDM Magazine, volume 6. Nweer 11, Noventer 1976.

6.

George E. Elsaesser, *5ysten Considerations In Inclementing Low Light Level Television Cameras," Dyra-Vision International, Anaheim, California 92806.

7.

George E. Elsaesser. "A User's Guide to Comercial tow Light Level Television Cameras."

Dyna-Vision Internaticul. Anaheim California 92806.

8.

9.

R. W. Engstrom & G. A. Robinson. " Choose The Tube-For L?TV." RCA-Electronics Components.

lancaster. Fennsylvania 17604 Reprinted for Electro-Optical Systems Design. June 1971.

10. "Au'.horized Federal Supply Schedule Price List." GSA Contract eGS-095-30389 Javelin Elec-troe lcs, Los Angeles. California 90045.

11. Kenneth A. Hoagland. " Application Techniques For CCTV Image Sensors." Fairchild Space &

Industrial Scientific Conference Managerent. Inc.

12.

E. Hart. "pecent Developments in 6.arge Coupled tevice (CCD) Technology," Fairchtid Security and Surveillance Systems. Syosset, New York 11791,

13. "The Fairchild MV-101 Television Camera." Fairchild Security and Surveillance Systers.

Syosset. New York 11711.

40

s

14. " Solid-State video Canera." and " Solid State Imaging Systems." General Electric Company.

Optoelectronic Systems Operation. Syracuse. New York 13201.

15. The Institute of Radio Engineers. " Monochrome Television Broadcast Receivers." AN5!. 1430 Broadway. New York. New York 10018. Approved August 9.1961 by American Standards Associa-tion. bulletin e60 IRE 17.51.

16. EIA 5tandard.

Electrical Performance Standards for Closed Circuit Television Camera 525/60 Interlaced 2:1.* Nover.ber 1966. EIA eR$-330. Electronic Industries Association. Engineering Dept. 2001 Eye St. NW., Washington D.C.

20?O6.

17. EIA Standard.

Electrical Performance Standards for Direct View High Resolution Monochrome Closed Circuit Television Monitors.* October 1974. EIA #RS-412-A. Electronic Industries Association. Engineering Dept. 2001 Eye St. NW., Washington. D.C.

20006.

18. Norelco. *Salanced Wire video Frequency Transmission Systen." Philips Broadcast Equipment Corp., Aadio-Video Systems Div. One Philips Parkway. Montvale. New Jersey 07645.

19. Grundig Electronic. " Professional Television Transmission Techniques." March 1974. Grundig Electronic Division. 8510 Furth/Bayern. Wirzburger Strasse 150. West Germany.

20. PCA. " Video Switching System Conponerts Type PTS-1," RCA Caunercial Electronic Systems Division. Front and Cooper Str6ets. Camden. New Jersey 08102.

21. RCA. " Video Distribution Arplifier. Type PDA-2A." RCA Corrnercial Electronic Systems Division.

f ront and Cooper Streets. Camden. New Jersey 08102.

3

22. DYNAIR ELECTRONICS. " Video Transmission Techniques." Dynair Electronics. 6360 Federal Blvd..

San Diego. California 92114

23. "Sur elllance Telemetry - EPO 789 Series.* Power-Optics. Inc.. P.O. Box 266. Fairview Village.

Penns,1vania 19409.

24. RCA. *5ynchronizing Generator. Type PSG-2." RCA Cornercial Electronic Systems Division.

Front and Cooper Streets. Camden. New Jersey 08102.

25. " Digital Control Systms." Evershed Power-Optics Limited. Bridge Wharf Bridge Rd., Cherlsey Surrey. kT!f2,tJ. England.

26.

"5NA Television Monitors." "ROS Series 14. 17. and 21 inch High Resolution Monitors." *RHT Professional Color Monitor." "RHN Professional Color Monitors.* "QQA Series 14. 17. and 21-inch High Resolution Monitors." "$10019-and 25-inch Color Television Monitors." "DIA Professtor,al Monitor." and "ENA Television Monitors: C0hRAC." Conrac Division. 600 North Rinsdale Ave.. Covina. Calitornia 91722.

41

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o

- - - - ~

' ~ ~ ~

27. EIA Standard. " Electrical Performance Standards for Direct View Monochrome Closed Circuit Television Monitors 525/60 Interlaced 2:1." October 1974. EIA #RS-375-A Electrt,nic Indus-tries Association. Engineering Dept. 2001 Eye St. NW., Washington. D.C.

20006.

28. " Planning For Closed-Circuit Television." RCA, Comercial Electronic Systems. Camden. New Jersey 08102.

29. Martin Dickstein "The Studio: Planning The New And Upgrading The Old." Industrial Photog-raphy. February 1974.

30.

G. Idhite. "The Care of Tape And Video Recorders in Closed Circuit Television." British Kinematograr,hy Sound and Television. September 1972.

31 Marry E. Kitchen. *! mage Motion sensor." 2416 Observatory Place NW., Washington, D.C.

20007

32. " Authorized Federal Supply Schedule Price List 1974-1975" & "GBC Motion Detector Model; VS-101." GBC TV Corp., 74 Fif th Ave., New York. New York 10011.

33.

C. Crowther. "Better Cameras or More Lights?" Security World, pp. 32-33. Nover.ber 1976.

34 Martin Dickstein. "borking With Your Video Cam ra." Industrial Phot: graphy. May 1974

p. 42.

35.

B. O. Berge. "Vigliance. A Guide to frproved Parforr.ance." Human Resources Research Of fice.

Bulletin 10. October 1963.

36. Attilio Mattera. "T.V. Appilcation For Law Enforcement." Night Visfor. laboratory. U.S. Army Electronics Comand. Fort Belvoir. Viginia 22060. 1972 Cornahan Conference on Crt e Counter-w asures Proceedings. University of Kentucky. Lexington. Kentu;ky 435C6.

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