This area can be broken down into the various subsystems, but the overall question is simple: Is everything working the way it should? Are images from cameras free of distortion and interference, and sharply focused? Do pan/tilt/zoom (p/t/z) cameras move when you tell them to and, more importantly, stop moving on command? Are images recorded as needed, and can you play them back on demand?
While these may seem like common-sense questions, it is surprising how many operators learn to compensate for systems that have deteriorated over time. Sometimes, an alternate camera is used, or they’ll wait until the subject gets closer to see if they can be recognized.