AI-CCTV Systems

The practical value of CCTV depends on seeing clearly, not on installing many cameras. We set pixel density by what each position must identify: spotting that someone walked past, and reading a face or a plate, differ by several times in specification. Every quotation itemises each camera's purpose and coverage — we do not gloss over it with phrases like thirty cameras site-wide.

Storage is sized backwards from the retention period. We first confirm whether the client needs 30, 60 or 90 days, then calculate from bitrate, camera count and recording mode, with twenty per cent headroom. Many sites were under-provisioned at the outset and can only retain seven days — and the footage is missing exactly when an incident happens. We make this explicit at the design stage.

AI analytics are not a panacea, and should not replace human monitoring. The genuinely useful functions fall into a few categories: fence or restricted-area crossing, excessive loitering in specific zones, crowd gathering, illegal parking, abandoned objects, and cameras blocked or moved. Each needs its sensitivity and time thresholds tuned on site — otherwise you get hundreds of false alerts a day and the frontline simply switches notifications off.

Privacy must be addressed from the start. Windows of residential units, neighbouring buildings' private space, and changing room and washroom entrances should all have masking zones. Audio recording is regulated by the Personal Data (Privacy) Ordinance in Hong Kong; unless there is a clear need and proper notification, we advise against enabling it. Camera positions and angles should be limited to the stated purpose, and not incidentally cover more than necessary.

The system can integrate with access control, parking and intercom: an intercom call pops up the relevant camera view; a recognised visitor plate alerts the management office in advance; a restricted-area alarm triggers recording and a push to the duty phone. These integrations should be built on open protocols (ONVIF, RTSP, API) rather than locking the client into one closed platform.

Remote viewing is convenient, but permissions must be tight. Management office supervisors, night-shift supervisors and engineers should have different levels; departing staff's accounts are deactivated immediately; outsourced contractors see only designated cameras. We configure all of this at handover and leave behind an account inventory.

Legacy analogue systems can be partially retained: encoders can bring existing cameras onto the new platform, so a full rip-and-replace is not always necessary. But image quality and low-light performance have real limits — we will say honestly which positions are worth replacing and which can serve another two or three years.