Licence Plate Recognition Parking Systems

What ANPR solves is identifying which car is which. The system reads the plate with a confidence value, checks it against the whitelist, visitor list or blacklist, and decides whether to open or hold the barrier — while archiving the plate image and a front-of-vehicle overview for later enquiries or dispute handling. It is an access management tool, not an extension of any police database, and we never present it that way to clients.

Hong Kong plates come in more than one format. Two-line plates, custom plates, motorcycle plates, trailer plates — plus dirt, plastic covers and reflective edges — all reduce recognition rates. The system can handle Hong Kong, Mainland China and Macau plates simultaneously, prioritising local plates. But for cross-border or dual-plated vehicles, we still recommend bringing a real vehicle to the lane for a live test, rather than judging by the specification sheet alone.

Lane conditions matter more than camera resolution. East- and west-facing entrances suffer backlighting, rainy nights bring ground reflections, downhill approaches and sharp bends tilt the plate, and fast or closely spaced vehicles can put two plates in a single frame. During the survey we record sun direction, lane length, gradient and queuing space before deciding camera height, focal length, lighting and trigger position — adding ground loops or radar where needed rather than relying on image triggering alone.

List management falls into three categories: residents and monthly parkers open the barrier automatically, with one bay able to register several plates though usually only one vehicle allowed inside at a time; visitors are pre-registered by property staff or residents and expire automatically; blacklist hits only notify the guard on duty — they do not mean a police report, and nothing is reported to any authority automatically. All entry and exit records can be searched by plate, date, lane and time period.

Existing barriers are not necessarily waste. Where the arm structure, motor and safety devices are sound, they can be retained with recognition cameras, displays and control modules added, at lower cost and shorter duration than full replacement. But where control interfaces are worn out, or there is no anti-collision or anti-drop protection, we recommend replacement — one barrier striking a car usually costs more in compensation and repairs than the price difference of a new barrier.

Narrow lanes are the most common challenge in Hong Kong's older car parks. Single-lane two-way flow, intelligent traffic light linkage, and time-shared entry and exit are all workable approaches. The design must also account for fire service access, emergency vehicle entry and power-failure release — not just look good on a drawing.

Deliverables include a lane test report (recognition performance across different times and weather), list and tariff rule configuration, display text, a fallback release procedure, and on-site training for security staff. When the system misbehaves, the frontline must know how to release a vehicle within a minute — not wait for someone to come and fix it.