ANPR Parking Explained

What is ANPR?

Automatic Number Plate Recognition (ANPR) — also known as License Plate Recognition (LPR) — is a technology that uses optical character recognition on camera images to read vehicle number plates automatically.

In parking, ANPR cameras are installed at entry and exit points to record when each vehicle enters and leaves a site. This data drives access control, payment calculation, permit verification, and enforcement workflows.

ANPR vs. Ticket systems

Traditional parking uses paper tickets to record entry time. ANPR replaces the ticket entirely — the plate becomes the identifier, and the software handles everything else automatically.

How ANPR works

The ANPR process involves three stages:

Image capture

A high-resolution camera captures an image of the vehicle as it passes the detection zone.

Plate detection

Computer vision algorithms identify the number plate region within the image.

Character recognition

OCR software reads the individual characters and converts them into a text string that is sent to the cloud platform.

ANPR in parking operations

Once the plate is identified, the PARQ platform uses it to:

Check against the whitelist for permitted vehicles
Start a parking session with a timestamp
Calculate the charge based on dwell time when the vehicle exits
Verify payment has been collected before opening the exit barrier
Flag non-paying vehicles for enforcement action

Factors that affect ANPR accuracy

Camera placement

Angle, height, and distance from the plate zone significantly affect read rates

Lighting conditions

Good cameras include IR illumination for consistent night performance

Plate condition

Dirty, damaged, or obscured plates reduce accuracy

Vehicle speed

Barrier entry/exit is typically low-speed. Faster applications need higher frame rates

GDPR and ANPR

Number plates are considered personal data under GDPR in the UK and EU. Operators using ANPR must ensure they have a lawful basis for processing, a documented data retention policy, and appropriate security controls.

PARQ is designed to support GDPR compliance, with configurable data retention periods, access controls, and audit logs. Operators should consult their data protection officer to ensure their specific deployment meets all applicable requirements.