Finding black borders in image

Hello community

I'm on a project on with I need to determine the beginning and the end of the top black border. I want this to tell the OCR from wich position the ROI begins.

From left to right I can see the black border in the plot of the sum of the bw image. But how can I "cut-off" the black part? Or at least determine how many pixels it has in height?

After the determination or crop, I'll set the ROI from 0 (or given offset) to a fixed value (size of the banner) to reduce the false information for the OCR.

Thanks in advance.

Answer 1

[yanqi liu]

yes，sir，may be upload your image file，let's use the follow method

bw2 = ~imclearborder(~bw);

[r,c] = find(bw2);

bw2 = bw(min(r):max(r),min(c):max(c));

figure; imshow(bw2);