Question

I am looking for an open source image processing libraries or APIs those provide me to create a program which captures the license plate of a car in a parking system and gives me the number plate as a text . It would be great if I can have it in managed code (c# or java).

Any help would be greatly appreciated.

Thanks in advance

Answer 1

There are no libraries that are going to explicitly give you the license plate from an image if the image is passed as an argument, at least open source. You have to use multiple functions within the library to transform, manipulate, and extract the information you want. This is considered a ‘solved’ problem within Computer Vision. If there were in fact an open source library to do what you want, I’m sure a lot of Companies selling LPR technologies would stop selling it because it wouldn’t be economically feasible.

The other problems you will have is the vast difference in license plate designs and styles. Your algorithm will have to be tweaked and tweaked constantly for ever changing license plates. For instance, in the US, the State of Florida has hundreds of license plates. It has been stated in the past that performing LPR on Florida license plates is one of the most difficult tasks.

OpenCV is the closest you will get. However, you will need to understand Fourier transforms and other advanced mathematical algorithms to derive the information you want.

This esnips site has various zipped solutions that other people have come up with. Some may or may not work.

You can also take a look at this CodeProject article on Image Recognition with Neural Networks