CST Video and Audio Surveillance Technology 2 — Questions and Answers
Question 1: What does the term 'latency' refer to in the context of IP surveillance systems?
- The resolution degradation over long cable runs
- The delay between image capture and display on the monitor (Correct answer)
- The time required to compress a video frame
- The interval between scheduled recording cycles
Correct answer: The delay between image capture and display on the monitor
Latency is the delay between when a camera captures an image and when it is displayed on a monitor, which is critical in real-time surveillance applications.
Question 2: Which IP camera feature allows it to operate without a separate power supply by receiving power through the network cable?
- ONVIF compliance
- Power over Ethernet (PoE) (Correct answer)
- H.265 encoding
- Wide Dynamic Range (WDR)
Correct answer: Power over Ethernet (PoE)
Power over Ethernet (PoE) delivers electrical power to IP cameras through the same Ethernet cable used for data, eliminating the need for separate power supplies.
Question 3: A surveillance camera is installed facing a window with bright outdoor light, causing subjects indoors to appear as silhouettes. Which camera feature would best correct this?
- Infrared illumination
- Wide Dynamic Range (WDR) (Correct answer)
- Varifocal lens adjustment
- Frame rate reduction
Correct answer: Wide Dynamic Range (WDR)
Wide Dynamic Range (WDR) technology allows a camera to capture detail in both bright and dark areas of the same frame, correcting silhouetting caused by backlighting.
Question 4: What is the primary function of an analog-to-digital encoder (video encoder) in a surveillance system?
- Convert digital IP camera streams to analog format for legacy DVRs
- Convert analog camera signals into digital IP streams for network transmission (Correct answer)
- Amplify analog signals over long coaxial cable runs
- Compress H.264 streams to H.265 format
Correct answer: Convert analog camera signals into digital IP streams for network transmission
A video encoder converts analog camera signals into digital IP streams, allowing legacy analog cameras to integrate into modern IP-based surveillance networks.
Question 5: Which audio surveillance microphone type is most directional and best suited for picking up sound from a specific distant source?
- Omnidirectional microphone
- Cardioid microphone
- Shotgun microphone (Correct answer)
- Boundary microphone
Correct answer: Shotgun microphone
A shotgun microphone has a very narrow pickup pattern (supercardioid or hypercardioid) and is highly directional, making it ideal for capturing sound from a specific distant source.
Question 6: What is the purpose of a dewarping algorithm in a fisheye surveillance camera system?
- Reduce video file size by removing redundant frames
- Correct the barrel distortion in fisheye images to produce normal-looking video (Correct answer)
- Enhance low-light performance by combining multiple frames
- Encrypt the video stream for secure transmission
Correct answer: Correct the barrel distortion in fisheye images to produce normal-looking video
Dewarping algorithms mathematically correct the barrel distortion inherent in fisheye lenses, converting the circular fisheye image into standard rectilinear views.
Question 7: In surveillance systems, what does ONVIF stand for and what is its primary purpose?
- Open Network Video Interface Forum; standardizes interoperability between IP-based security products (Correct answer)
- Online Network Video Integration Framework; encrypts video streams
- Open Node Video Input Format; defines recording file formats
- Optical Network Video Interface Foundation; specifies fiber-optic camera standards
Correct answer: Open Network Video Interface Forum; standardizes interoperability between IP-based security products
ONVIF (Open Network Video Interface Forum) is an industry standard that ensures interoperability between IP-based security products from different manufacturers.
CST Video and Audio Surveillance Technology 2
What does the term 'latency' refer to in the context of IP surveillance systems?