Video Surveillance and CCTV Flashcards

What does the term 'pixel density' mean in CCTV camera planning, and why is it important?

Answer: The number of pixels covering a unit of space in the scene, determining the level of detail captured

Pixel density (pixels per foot/meter in the scene) determines how much detail is captured about subjects, directly affecting whether the system meets identification, recognition, or detection requirements.

Under the Americans with Disabilities Act (ADA) and US privacy law, which area is generally PROHIBITED for video surveillance installation in a workplace?

Answer: Restrooms and changing rooms

Video surveillance in restrooms and changing rooms is prohibited under US federal and state privacy laws because individuals have a reasonable expectation of privacy in these locations.

What is a 'video analytics' false positive in the context of a security surveillance system?

Answer: The system generates an alarm for a non-threatening event such as an animal or blowing debris

A false positive (nuisance alarm) occurs when the analytics system triggers an alert for a benign event, such as a shadow, animal, or environmental condition, wasting operator attention.

For a camera monitoring a vehicle entry gate, what frame rate is the minimum recommended to reliably capture readable license plates on vehicles traveling at normal entry speeds?

Answer: 25-30 frames per second (fps)

25-30 fps is the minimum recommended for license plate capture at vehicle entry gate speeds, as lower frame rates cause motion blur that makes plates unreadable.

What is the purpose of an NVR (Network Video Recorder) as compared to a DVR (Digital Video Recorder) in modern IP surveillance systems?

Answer: NVRs process and record IP camera streams via the network without requiring direct connection to each camera

An NVR receives pre-compressed IP video streams from cameras over the network, while a DVR connects directly to analog cameras and encodes the video itself, limiting scalability and placement flexibility.

What surveillance camera feature allows automatic adjustment of the iris aperture to maintain proper exposure as lighting conditions change throughout the day?

Answer: Auto Iris (AI) lens / Direct Drive Iris (DDI)

An Auto Iris (AI) or Direct Drive Iris lens automatically adjusts its aperture in response to changing light levels, maintaining proper exposure from bright daylight to low-light evening conditions.