CCTV Video Surveillance System Design 4 — Questions and Answers
Question 1: What is the primary function of a video management system (VMS) in a large-scale CCTV deployment?
- To compress video files for efficient storage
- To centrally manage, record, and retrieve video from multiple IP cameras (Correct answer)
- To convert analog cameras to digital format
- To power cameras over Ethernet cabling
Correct answer: To centrally manage, record, and retrieve video from multiple IP cameras
A VMS provides a centralized software platform for managing IP camera feeds, configuring recording schedules, and searching archived video across a large installation.
Question 2: When designing a CCTV system for a school, which privacy consideration is most critical?
- Avoiding cameras with color imaging
- Ensuring cameras do not cover restrooms, locker rooms, or other private areas (Correct answer)
- Using low-resolution cameras to reduce data storage
- Placing all cameras outdoors only
Correct answer: Ensuring cameras do not cover restrooms, locker rooms, or other private areas
Legal and ethical requirements prohibit camera placement in areas where individuals have a reasonable expectation of privacy, such as restrooms and locker rooms.
Question 3: What is the purpose of camera masking (privacy zones) in a CCTV system?
- To increase the camera's night vision range
- To block out specific areas within the camera's view from being recorded or displayed (Correct answer)
- To mask the camera housing from being visible
- To mask interference from neighboring wireless signals
Correct answer: To block out specific areas within the camera's view from being recorded or displayed
Privacy masking allows administrators to digitally block portions of the camera's view (e.g., a neighbor's window) to comply with privacy laws or organizational policy.
Question 4: Which cable type is the industry standard for transmitting both power and data to IP cameras in modern system designs?
- RG-59 coaxial cable
- Cat5e or Cat6 Ethernet cable with PoE (Correct answer)
- Fiber optic cable
- RS-485 twisted pair cable
Correct answer: Cat5e or Cat6 Ethernet cable with PoE
Cat5e/Cat6 with Power over Ethernet (PoE) is the standard for IP cameras, delivering both network data and electrical power through a single cable run.
Question 5: What is 'ONVIF' compliance important for in a multi-vendor CCTV system design?
- It ensures cameras meet outdoor weatherproofing standards
- It provides interoperability between cameras and VMS from different manufacturers (Correct answer)
- It guarantees end-to-end video encryption
- It certifies the camera for use in government installations
Correct answer: It provides interoperability between cameras and VMS from different manufacturers
ONVIF is an open industry standard that allows cameras, recorders, and software from different manufacturers to communicate and work together seamlessly.
Question 6: A designer needs to calculate storage for 16 cameras recording continuously at 4Mbps for 30 days. What is the approximate total storage required?
- About 500 GB
- About 2 TB
- About 10 TB (Correct answer)
- About 26 TB
Correct answer: About 10 TB
16 cameras × 4 Mbps × 86,400 sec/day × 30 days ÷ 8 bits/byte ÷ 1,000,000,000 ≈ 20.7 TB, making ~26 TB the closest realistic estimate with overhead.
Question 7: What is the main design consideration when placing cameras near bright light sources such as windows or floodlights?
- Selecting cameras with higher frame rates
- Avoiding backlight situations or choosing cameras with BLC or WDR (Correct answer)
- Using cameras with longer focal lengths
- Increasing the recording bitrate to compensate
Correct answer: Avoiding backlight situations or choosing cameras with BLC or WDR
Bright light sources behind subjects cause silhouetting; Back Light Compensation (BLC) or WDR technology corrects this to provide usable images of subjects.
CCTV Video Surveillance System Design 4
What is the primary function of a video management system (VMS) in a large-scale CCTV deployment?