How can we plot pixel difference histogram accurately?

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function PDH(img1,img2)
diffImage2 = imfilter(img2, [1, -1]);
diffImage1 = imfilter(img1, [1, -1]);
minValue1 = min(diffImage1(:));
maxValue1 = max(diffImage1(:));
minValue2 = min(diffImage2(:));
maxValue2 = max(diffImage2(:));
[counts2,edge2] = histcounts(diffImage2(:));
[counts1,edge1] = histcounts(diffImage1(:));
end
problem occures when trying plotting edge against counts cause size of edges always exceeds counts by one. However,
edges1 = linspace(minValue1, maxValue1, numel(counts1)) &
edges2 = linspace(minValue2, maxValue2, numel(counts2)) solve the problrm but the shape is not clear unless achieving decimation by certain number e.g 10.
plot(edges1, counts1, edges2, counts2); % Overlapped
plot(edges1(1:10:end), counts1(1:10:end), edges2(1:10:end), counts2(1:10:end));% looks better
Is there more accurate procedure to automatically fit the gragh with proper edges scaling.
Regards

Answers (1)

Walter Roberson
Walter Roberson on 8 Mar 2021
problem occures when trying plotting edge against counts cause size of edges always exceeds counts by one.
So plot(edge2(1:end-1), counts2) and the problem is solved.
Or use histc(), in which case the last bin will exist and will count only the values that exactly equal the upper bound of the edges.

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