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Licence plate

asked 2013-07-07 15:05:39 -0500

Hi everybody. Have you got an example on how can I detect the license plate of a car?

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answered 2013-07-07 17:00:04 -0500

See the book "Mastering OpenCV with Practical Computer Vision Projects", chapter 5, with the code source on GitHub here. It trains an SVM and performs OCR recognition too. The main issue you will encounter after is to find a database of such plate to train your system. To the best of my knowledge, it doesn't exist because of privacy issue.

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@Mathieu Barnachon They stated in the book and also in the code that their algorithm is varient to the specific standard like licence plate should be of specific Height and Width and image taken from specific space like 3-4 meters, so do we have any algorithm or the way which is invarient of this ? in which it detect the licence plate which we don't have knowledge of its width and height , even don't have a idea of it , and every vehicle have different size's and color of licence plate


FLY gravatar imageFLY ( 2013-09-22 04:58:55 -0500 )edit

The parameters are mostly for the code. If you have a different configuration of licence plates, you probably have to train many classifier (one per configuration). You also have to adapt the plate detection to the targeted shape. This book is just a quick starter, not a full application.

Mathieu Barnachon gravatar imageMathieu Barnachon ( 2013-09-22 12:55:57 -0500 )edit

@Mathieu Barnachon +1 , You also have to adapt the plate detection to the targeted shape. , i did it by detecting square shape in the vehicle , but some are rectangle and some are square , how to handle that problem

FLY gravatar imageFLY ( 2013-09-22 13:23:22 -0500 )edit

The easiest way is to use two different detectors. The same issue is for the number groups (XX - XX or XXX - YY - ZZ, etc.) You probably have to test many detector to reach an acceptable recognition rate.

Mathieu Barnachon gravatar imageMathieu Barnachon ( 2013-09-22 14:06:22 -0500 )edit

on my pc (i5) it is very slow (minutes), have others same problem?

niqt gravatar imageniqt ( 2013-10-08 06:01:41 -0500 )edit

answered 2013-07-11 05:16:37 -0500

elmiguelao gravatar image

There's also some code for Automatic Number Plate Recognition (ANPR) here in EmGu but very easily portable to OpenCV using contours. I think is oriented towards close range pictures, like those taken in public parking lots and then identifying the characters, which might or might not be what you are looking for.

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Asked: 2013-07-07 15:05:39 -0500

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Last updated: Jul 11 '13