CCTV Video Surveillance System Design 5 — Questions and Answers
Question 1: What is the key advantage of using PTZ (Pan-Tilt-Zoom) cameras in a surveillance system design?
- They eliminate the need for any fixed cameras in the system
- They can cover a large area and zoom in on incidents under operator control or via automation (Correct answer)
- They are always less expensive than fixed cameras
- They do not require any network infrastructure
Correct answer: They can cover a large area and zoom in on incidents under operator control or via automation
PTZ cameras provide flexible, wide-area coverage with the ability to zoom in on specific incidents, making them ideal for large open areas with active monitoring.
Question 2: In a risk-based CCTV design approach, which area would typically be classified as 'high risk' requiring the most camera coverage?
- A rooftop mechanical room with no public access
- A loading dock with high-value goods and frequent external access (Correct answer)
- An interior filing room used only by two employees
- A fenced perimeter with no entry points
Correct answer: A loading dock with high-value goods and frequent external access
Loading docks combine high-value assets, external personnel access, and limited supervision, making them high-risk zones that require intensive camera coverage.
Question 3: What does 'pixels per foot' (PPF) or 'pixels per meter' measurement determine in CCTV design?
- The total pixel count of the camera sensor
- The image detail available for a given subject size, determining if identification is possible (Correct answer)
- The number of cameras required per square foot of coverage area
- The frame rate needed for smooth motion capture
Correct answer: The image detail available for a given subject size, determining if identification is possible
PPF/PPM defines how much image detail is available for a target at a given distance, directly determining whether the system can detect, recognize, or identify a person.
Question 4: When a designer specifies 'detection' level coverage versus 'identification' level coverage, what is the main difference?
- Detection uses color cameras; identification uses black-and-white
- Detection confirms presence of a person; identification captures enough detail to recognize who the person is (Correct answer)
- Detection records continuously; identification only triggers on motion
- Detection uses analog cameras; identification uses IP cameras
Correct answer: Detection confirms presence of a person; identification captures enough detail to recognize who the person is
Detection verifies that a person or object is present in an area, while identification requires sufficient image resolution to distinguish specific facial or physical features.
Question 5: What redundancy measure is commonly designed into critical CCTV systems to prevent total recording loss during a power outage?
- Backup VHS tapes stored offsite
- Uninterruptible Power Supplies (UPS) and/or backup generators (Correct answer)
- Dual coaxial cable runs per camera
- Manual camera rotation by security guards
Correct answer: Uninterruptible Power Supplies (UPS) and/or backup generators
UPS units provide immediate battery backup during power interruptions, while generators ensure long-term operation, preventing gaps in critical surveillance recording.
Question 6: Which network topology is most commonly used in IP-based CCTV system design to connect cameras to an NVR or VMS server?
- Ring topology
- Mesh topology
- Star topology using network switches (Correct answer)
- Bus topology
Correct answer: Star topology using network switches
Star topology connects each IP camera to a central network switch, which then connects to the NVR/VMS, providing easy troubleshooting, scalability, and isolation of faults.
Question 7: What is the purpose of conducting a 'camera coverage audit' after a CCTV system is installed?
- To verify the brand labels on all installed cameras
- To confirm actual camera views match the designed coverage plan and identify any remaining blind spots (Correct answer)
- To update the firmware on all cameras simultaneously
- To calculate the final invoice for the client
Correct answer: To confirm actual camera views match the designed coverage plan and identify any remaining blind spots
A post-installation coverage audit validates that each camera achieves its intended field of view, image quality, and coverage overlap as specified in the design documentation.
CCTV Video Surveillance System Design 5
What is the key advantage of using PTZ (Pan-Tilt-Zoom) cameras in a surveillance system design?