Recognize vehicle with no plate


#1

If I understand the pipeline correctly, one of the first steps is to locate plate candidates in the input image. Is the training done in such a way that you could still get a result in case the plate itself is blank or missing? I am thinking of cases where the sun is being reflected directly behind the camera, overexposing the plate, or the plate being covered in snow. Or simply removed.

Is there a way to still run the vehicle classification algorithm even if the plate is unreadable? I realize it may be difficult to group the results into a single detection without any plate information.


#2

It’s possible to disable the portion that recognizes the text on the plate, which would provide you with all possible plate candidates in the image. Add this to /etc/openalpr/openalpr.conf:
skip_recognition = 1

However, you would not get the plate numbers, and there would be more false positives in the output.

Finding the vehicles even when there is no plate is a very common request from customers. It’s a tricky problem to solve, but we are on the path towards doing that, and should have a great feature next year.


#3

+1 feature request. Some no-plate vehicles (neither front nor rear) retain a frame, even when tape used to obscure number, which is possibly of use to an algorithm. Much more common is no front plate, required, but not rigorously enforced in California.