How to extract the plate area only from black background

Question

mohamed 2012-8-3

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https://ww2.mathworks.cn/matlabcentral/answers/45201-how-to-extract-the-plate-area-only-from-black-background

评论： Rinku 2014-12-31

Hi, i want to know how to crop the plate area only from the image shown below my code takes the RGB image & outputs this image, so i need only a way to extract the numbers area only here is the output picture

thanks in advance

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Answer 1

Andrei Bobrov 2012-8-3

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https://ww2.mathworks.cn/matlabcentral/answers/45201-how-to-extract-the-plate-area-only-from-black-background#answer_55354

在 MATLAB Online 中打开

II=im2bw(I);
s=regionprops(II,'Area','BoundingBox');
[ii,ii] = sort([s.Area],'descend');
out = imcrop(I,s(ii(2)).BoundingBox);

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mohamed 2012-8-3

编辑：mohamed 2012-8-3

在 MATLAB Online 中打开

thanks for you all i did it at last thanks again but u must fix your code like this:

II=im2bw(I);
s=regionprops(II,'Area','BoundingBox');
[~,ii] = sort([s.Area],'descend');
out = imcrop(I,s(ii(1)).BoundingBox);

Rinku 2014-12-31

thank you both of you..this code is help me very much..

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Answer 2

Image Analyst 2012-8-3

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https://ww2.mathworks.cn/matlabcentral/answers/45201-how-to-extract-the-plate-area-only-from-black-background#answer_55350

You could pass the image into regionprops() and ask for area and eccentricity. The plate will have a lower eccentricity than the lines, and probably but not necessarily a larger area than any/most/all of the lines. But I can't tell that that rectangular blob with a bunch of holes in it in the lower left is not also another license plate. At least for this one particular image, you could get rid of that based on area or FilledArea.