Enhance low quality License Plate image to binarize them.

Hi all

I have some License Plate images which have poor quality, I tried some contrast enhancement methods like HE,BHE,CLAHE,RSIHE and ... , but when I binarize them with otsu's method or some local thresholding algorithms like NIBLACK,SAUVOLA and ... , I don't get satisfied results.

please tell me how can enhance this images??

original images:

results of binaraization:

what is the problem of this images?(low contrast??) how can I improve results? thanks for your help, any idea will be welcome.

Answer 1

[Image Analyst]

It's not really a MATLAB question yet. You can find papers on super resolution and license plate recognition here: http://www.visionbib.com/bibliography/contents.html I'm sure you're not the first person to deal with poor quality license plate images. Find out how the other people dealt with it in their published papers.

[sara]

thanks dear @Image Analyst for your answer. what is the problem of my images?? contrast or resolution ? or both of em? I studied some paper about resolution. is there any other way to solve this problems? super-resolution is expensive aspect of time and hard to implement for me.

thanks sir for your time.