ASIS CPP - Physical Security (Part 2) Flashcards
Video surveillance systems
When selecting a video surveillance
Uses a systems approach rather than a components approach
Video surveillance systems
The following parameters determine the effectiveness of a video assessment subsystem
- Minimum time between sensor alarm & video display
- Complete video coverage of the sensor detection zone (called the assessment zone when sensors & video are integrated)
- Ability to classify a 1 ft. target at the far edge of the assessment zone
- Vertical field of view at the far edge of exterior detection zone = height of a standard fence & person climbing it
Parameters Ctd…
- Continuous operation, 24/7
- Minimal sensitivity to environmental conditions, for all cameras
- Minimal obscuration of the assessment zone (such as trees, fences, furniture, etc)
- Camera FOV & recording system integration displays the alarm source to an operator
Video Surveillance
3 reasons for cameras in security applications
- Obtain visual information about something that is happening (most important)
- Obtain visual information about something that has happened (most important)
- Deter undesirable activities
Video Surveillance
Primary uses of video surveillance systems
Detection of Activities
Recording of Incidents
Assessment of Alarms/Incidents
Video Surveillance
Main elements of video surveillance systems
Field of View (FOV)
Scene
Lens
Camera (including mounting hardware)
Transmission Medium
Monitor
Recording Equipment (analog/digital)
Control Equipment
Video Surveillance
Three main components of an analog video surveillance system
Camera
Transmission Cable
Monitor
Video Surveillance
3 main components of a digital video surveillance system
Camera
Digital electronic signal center
PC with software
Video Surveillance
In designing a video surveillance application security managers should keep in mind
- Video surveillance is a visual tool of security & should be applied accordingly
- Video surveillance systems should always be designed with future growth or changes to the needs of the application in mind
Designing Video Surveillance Ctd…
No matter what, the equipment of the system will become obsolete
- Obsolete does not necessarily mean ineffective or out of date for the application
- If a system is obsolete but performing well, its because the original application was correctly designed to meet performance needs
Key points for designing VS systems
- Once simplified the most complex electronic system can be managed by almost anyone
- The application drives the choice of equipment not the other way around
Video Surveillance
Simple Rules For Design
Keep system in perspective
Design generically
Design for best options first (budget after)
Don’t feel driven to build the system all at once
Video Surveillance
Steps for design
- Define the system’s purpose
- Define each camera’s purpose
- Define the area to be viewed by each camera
- Choose a camera style
- Choose the proper lens
- Determine best transmission method
- Layout control area
Video Surveillance
Resolution is determined by the following in order
- Camera
- The transmission method
- The weakest link in the video system interface
- The reproduction capability of the storage system
Limiting Factors
- Analog video recorders average a playback of 225 horizontal lines (very low)
- DVR’s digitize analog signals, dropping 25% of the resolution
- Sloppy installation or cheap coaxial cable costs 10 - 15% resolution
- Digital compression also reduces the resolution
Video Surveillance
All IP cameras measure resolution as a multiple of the Common Intermediate Format (CiF) about half the average 325 horizontal lines; not recommended as a usable standard for storage
- 1/4 CIF = 176 x 120 (3,520 pixels or .003 MPX)
- CIF = 352 x 240 (84,480 pixels or .08 MPX)
- 4 CIF = 704 x 480 (337,920 pixels or 0.3 MPX)
- 16 CIF = 1408 x 960 (1,351,680 pixels or 1.3 MPX)
- 32 CIF = 2816 x 1920 (5,405,720 pixels or 5.4 MPX)
- A 4 mp camera = resolution of 400 ASA film
- A 6mp camera = resolution of 100 ASA film
- most effective & current standard for digital video compression is the H.264 compression algorithm
3 Considerations when determining video surveillance field & view (FOV)
Target (person, vehicles, etc…)
Activity (assault, slight of hand)
Purpose (identification vs. general monitoring)
Video surveillance systems are designed to be only two things
Visual assessment (what’s happening now)
Visual documentation (What happened previously)
3 Theoretical identification views of an analog VSS
1. Subject identification
2. Action identification
3. Scene identification
VS - Fields of view (FOV)
Theoretical identification views of a digital VSS
General: Can’t distinguish clothing & color - pixelated zoom (5 pix/ft)
Monitor: General vehicle/human traffic flows - no serious detail on zoom (7 pix/ft)
Detect: Detect but not identify person-sized object - no significant detail on zoom (4 pix/ft)
Observe: Clothing/colors gain distinction - no good detail on zoom (18 pix/ft)
Recognize: High degree of accuracy identifying & separating known individuals - good detail on zoom (35 pix/ft)
ID views of a digital VSS
Subject ID: Establish identity beyond a shadow of a doubt - the excellent detail on zoom (48 pix)
License Plat ID: ID of license plates - excellent detail on zoom (70 pix)
Facial Recog: Extreme details - excellent detail on zoom (88 pix)
VS - FOV
Identification of an object in video means…
The ability to differentiate between people’s identity
VS - FOV
Classification of an object in video means…
The ability to differentiate between humans animals etc…
VS - FOV
Cameras should not be required to view more than one major and one more minor objective