Original Image

1-RGB To Gray:

2-Image Denoising: Bilateral Filter

3-Histogram Equalization:

4-Erosion & Dilatation:

5-Image Subtraction Or Pixel Subtraction:

6-Image Tresholding:

7-Edge Detection:

8-Extension:

And then contour process...

This part is not available in the code. I did this with python but it can also be done in java. Maybe I'll add later

Finally find the license plate area...