MATLAB: I have a black and white image, how can I find the area percentage of the black areas

image processingregions

I have this black and white image. What I need is the percentage of the black areas. I first change the contrast so the black and white areas are more distinguishable. but I don’t know how to proceed from here. I'd appreciate if someone let me know which function(s) I should use.

Best Answer

Assuming you've "binarized" the image, so that black=0 and white=1,

percentageBlack=(1-nnz(image)/numel(image))*100

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invertedI = ~BW
%or
invertedI = not(BW)

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Measure the ratio of black and white from the binarized image?

Here bw_image is a input binary image.

[rows colm]=size(bw_image);
white_pixels=sum(bw_image(:));
black_pixels=~bw_image;
black_pixels=sum(black_pixels(:));
result=bwareafilt(~bw_image,1,'Largest');
outer_black=sum(result(:));
% Area with respect to circle only
black_pixels_area=(black_pixels-outer_black)/((rows*colm)-outer_black);
fprintf('The Percentage of black pixels covered area is %.2f ',black_pixels_area);
fprintf('\n The ratio black/white is %.2f',black_pixels/white_pixels);

Best Answer

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