Requirements for ANPR

For reliable number plate detection and recognition, ensure that your system meets the following requirements.

Camera

HPE recommends a separate camera for each lane of traffic. If you use a single camera for several lanes of traffic, high-definition recording is required (1080p or better).

Manually focus the camera on the middle of the region where number plates are read, and use a fast shutter speed to avoid blurring.

Image contrast The contrast must be sufficient for the number plates to be human-readable. If you are reading retroreflective number plates, the best results are obtained with infra-red (IR) illumination.
Number plate size The number plates must be human-readable and characters in the video must not be less than 10 pixels high.
Number plate rotation Position the camera above the traffic, so that number plates appear to be horizontal. The closer the plates are to horizontal, the better the performance.
Video frame rate Media Server improves accuracy by reading number plates across multiple frames. For moving traffic Media Server requires 25 or 30 frames per second. Do not reduce the frame rate of the captured video.

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