CCTV CCTV System Components 4 — Questions and Answers
Question 1: What is the purpose of an 'IR cut filter' (ICR) in a CCTV camera?
- Block visible light to enable color imaging at night
- Automatically switch between blocking and passing infrared light depending on lighting conditions (Correct answer)
- Reduce glare from highly reflective surfaces
- Filter out radio frequency interference from the image sensor
Correct answer: Automatically switch between blocking and passing infrared light depending on lighting conditions
An ICR mechanically moves an IR-cut filter in front of the sensor during daylight for accurate color reproduction and removes it at night to allow IR light to enhance low-light sensitivity.
Question 2: A technician installs a video balun on a CCTV system. What problem does this device solve?
- It boosts the signal strength of fiber optic cables
- It allows transmission of video over unshielded twisted pair (UTP) cable instead of coaxial cable (Correct answer)
- It converts digital IP video streams to analog composite output
- It synchronizes multiple cameras to a single reference clock
Correct answer: It allows transmission of video over unshielded twisted pair (UTP) cable instead of coaxial cable
A video balun converts the impedance of an analog video signal so it can be carried over inexpensive Cat5/Cat6 UTP cable instead of coaxial cable.
Question 3: What is the significance of a camera's 'minimum illumination' specification?
- The maximum brightness level before the image sensor saturates
- The lowest light level at which the camera can still produce a usable image (Correct answer)
- The required lux level for accurate color rendering
- The power consumption level at minimum operating voltage
Correct answer: The lowest light level at which the camera can still produce a usable image
Minimum illumination specifies the lowest light level (in lux or lux-equivalent) at which the camera can capture a recognizable image, indicating its low-light capability.
Question 4: In an analog CCTV system, what does a 'video distribution amplifier' (VDA) do?
- Converts analog video to HDMI for modern monitors
- Splits one video signal into multiple identical outputs while maintaining signal strength (Correct answer)
- Compresses video data to reduce storage requirements
- Adds timestamp and camera ID text overlays to the video signal
Correct answer: Splits one video signal into multiple identical outputs while maintaining signal strength
A VDA takes a single analog video input and distributes it to multiple outputs simultaneously, buffering each output to prevent signal degradation from splitting.
Question 5: Which camera form factor is most suitable for discreet indoor surveillance where the camera should be nearly invisible?
- Box camera with a large telephoto lens
- Pinhole camera (Correct answer)
- Dome camera with visible housing
- Bullet camera mounted on a wall bracket
Correct answer: Pinhole camera
Pinhole cameras use an extremely small lens opening that can be concealed behind a tiny hole in a wall, ceiling tile, or everyday object, making them nearly undetectable.
Question 6: What is the function of a CCTV system's 'motion detection zone' setting?
- Define areas of the frame where the camera automatically zooms in
- Restrict recording or alerts to specific regions within the camera's field of view where movement is relevant (Correct answer)
- Set the geographic boundaries for camera PTZ patrol routes
- Configure the infrared illuminator's coverage angle
Correct answer: Restrict recording or alerts to specific regions within the camera's field of view where movement is relevant
Motion detection zones allow operators to define specific areas within the frame that trigger recording or alerts when motion is detected, ignoring movement in excluded areas like busy streets.
Question 7: What is the advantage of H.265 (HEVC) compression over H.264 in IP camera systems?
- H.265 is compatible with older DVR hardware
- H.265 delivers equivalent video quality at approximately half the bit rate of H.264 (Correct answer)
- H.265 eliminates the need for a network switch in IP systems
- H.265 supports analog coaxial transmission natively
Correct answer: H.265 delivers equivalent video quality at approximately half the bit rate of H.264
H.265/HEVC uses more advanced compression algorithms to achieve the same perceived video quality as H.264 at roughly 50% lower bit rate, reducing storage and bandwidth requirements.
CCTV CCTV System Components 4
What is the purpose of an 'IR cut filter' (ICR) in a CCTV camera?