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CCTV Surveillance Coverage Study

Nowadays, CCTV (Closed Circuit Television) systems are used widely for ensuring safety, monitoring traffic, and preventing crime in many public  
and private spaces. However, the effectiveness of CCTV coverage is often achieved through design experience and trial-and-error, instead of being evaluated and visualized using a robust approach.

CCTV  Coverage  study  indicates  how  effectively  a  target  area  is  being  monitored  by  a CCTV  surveillance system.  As  quantitative  measures  of  surveillance  performance,  we  propose  the following  two  indicators:  surveillance  resolution,  and  surveillance  coverage index. Surveillance resolution indicates how closely a specific object can be monitored termed as Identification  with  a  CCTV  system,  depending  on  the  location,  mounting  heights  , and orientation  of  the  object  as  well  as  the  cameras  of  the  CCTV  system  , for  instance,  the personal entering. Surveillance coverage index focuses on a specific region rather than an object,  indicating  how  completely  a  region  of  interest  can  be  monitored  termed  as Detection  with  more  than  a  specified  surveillance  resolution.  The  region  can  also  be  the Main  entrance  of  the  Plant,  Tank  farm,  flares  Well  Pads  , and  Process  areas.   

Coverage  shall  be  able  to  zoom  in  to  view  object  level  day  or  night  and  shall  avoid  sun effect and fixed obstruction structures including outdoor equipment shades. The coverage shall  take  into  account  the  zero-manning  philosophy  of  the  project  and  ensure  100% coverage of the CDS and off-plot wells.

Reports shall have the direction of coverage, the radius of the coverage, and field of view calculation (FOV) as a minimum. The report will provide recommendations to avoid Blind Spot Areas.

 

Design Criteria For Selection Of Camera Location And Lens Size

1.1 Camera Zone and Color Scheme (DORI)

A  camera  cannot  see  with  equal  clarity  at  all  distances  which  means  that  the  level  of perception varies with distance. This makes the quality of surveillance different at different distances  and  depending  on  the  exact  application  or  situation;  different  zones  are identified for the purpose as discussed below.

One  of  the  most  important  characteristics,  affecting  the  efficiency  of  a  video  surveillance system,  is  the  ability  to  distinguish  objects  at  different  distances.  The  Coverage  study software allows seeing which parts of the camera field of view have the required resolution to identify, recognize, detect, and monitor different video surveillance objects.

By  default,  the  program  shows  camera  zones according to  European  Union standard  EN 50132-7 from 2013. There are several types of zones will be shown in the CCTV coverage study document as listed below:

    • Identification zone  (red).  In this area, you can positively identify a  person beyond a reasonable doubt. Pixel density = 250 pixels per meter.
    • Recognition zone (yellow). In this area, you can recognize a person known to you. Pixel density = 125 pixels per meter.
    • Observation zone (green). In this area, some details of the individual, such as clothing, can be seen. Pixel density = 62 pixels per meter.
    • Detection zone (light-green). This is an area where you will be able to detect the presence of a person. pixel density = 25 pixels per meter.  
    • Monitoring zone (blue). This zone is used to monitor the traffic flow or the movement of people without the need of identifying specific objects. Pixel density = 12 pixels per meter.

 

Standards we follow for performing the PA/GA Coverage Study

 1. ARAMCO

 2. SABIC

 3. NFPA

 4. ISO

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1.2 Camera Installation Height

The camera Installation height shall be considered 6 meters however the final height will be confirmed via a coverage study report for security monitoring. With regards to Process monitoring the camera height shall be based on the existing structure that shall be chosen.

 

CCTV coverage Study

 1.3 Resolution

The Resolution shall be chosen as 1920X1080 in the software.

1.4 Lens Angle of View and Field of View.

FOV allows for coverage of an area rather than a single focused point. In virtual reality a large FOV is essential  to  getting  an immersive,  life-like experience.  Wider FOV also provides better sensor coverage. The following parameter shall be considered for Field of View.

1. Distance:  Distance  from  the camera  to  the  target  is  the maximum  distance  between camera and the object of interest.

2. Field  of  view  Height:  Height  of  a  target  which  to  is  seen  at  a  specified distance.

3. Field  of  width:  Maximum  width  of  visible  area  at  the  specified  distance  from  the camera.

4. Viewing Angles:

  (a) Horizontal angle - camera's angle of view in width. The camera's focal length and field of view are hanged by setting this parameter.

  (b) Vertical angle - this is calculated automatically and cannot be changed.

 

1.5 Fixed Camera

As per EN 62676-4; 2015(horizontal), px/m standards; the camera color zone for Identification is identified when monitoring the target  – Fixed Camera for Coverage Study used respectively:

 

1.6 PTZ Camera

PTZ surveillance cameras will be installed to cover different areas require for monitoring, and zooming on ongoing processes, operations or rescues. PTZ camera is having a variable lens with a focal length from 4.1mm (wide) – 120mm (tele) which can be zoomed in or zoomed out to identify the target using a joystick/mouse. As per EN 62676-4; 2015 (horizontal), px/m standards; the camera color zone for Recognition is identified when monitoring the target – PTZ Camera for Coverage Study used respectively:

 

1.7 Flare Monitoring Camera

Flare monitoring cameras will be installed to cover flare areas require for monitoring, and dedicated to monitoring the flare operation. Flare Monitoring cameras are with a focal length of 50mm however the focal may vary based on the coverage report. As per EN 62676-4; 2015(horizontal), px/m standards; the camera color zone for Identification is identified when monitoring the target.

 

1.8 Focal Length

As a minimum standard, many of the manufacturers will provide a focal length as 4.1-120 mm for PTZ cameras and very-focal lens 3-9mm, for fixed cameras nevertheless the lens size will be varied based on the coverage report. The focal length for Flare cameras will be considered 50mm.

 

1.9 Network Bandwidth and storage calculation

The following parameters are considered for the Network Bandwidth and Storage calculation.

CCTV coverage Study report

(a) No of Cameras

(b) Resolution

(c) FPS (PAL 25/NTSC 30)

(d) Bitrates (Based on the resolution)

(e) Duration of recording

(f) No of Days

(g) The bandwidth requirement for 1 no. of CCTV camera for control and monitoring is considered to be 2 Mbps (2 Streams)

 

Aarmtech offers CCTV surveillance coverage study services to check the efficiency of indoor & outdoor CCTV cameras.

 

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