MATLAB: Moving a greyscale image such that the lowest pixel with an intensity above 0 is at the bottom of the image.

image analysisimage processingImage Processing Toolboximage segmentation

I'm trying to translate a greyscale image such that the bottommost pixel with an intensity>0 is at the bottom of the pic, I already have it such that the left most pixel . My code for translating is as follows: lungc_ref = imref2d(size(c)) [row, column] = find(c, 1, 'first'); [row2 column2] = find(c, 1, 'last'); t = [1 0 0; 0 1 0; -(column-1) (256-row2) 1]; tform = affine2d(t); imwarp(c, tform); [c_translated,lungc_ref] = imwarp(c,tform,'OutputView',lungc_ref); imshow(c_translated, [0 1000])

Best Answer

Use the circshift function, which shifts arrays along one dimension. Here is an example:
%generate an image (matrix)
A = rand(6,9)
%find linear index of the minimum value
[~,ix] = min(A(:));
%convert linear index into subscript index
[r,c] = ind2sub(size(A),ix)
%shift image rows to put the lowest valued pixel at the bottom
Y = circshift(A,size(A,1)-r,1)
%additionally, you can also shift image columns to put the lowest valued pixel at the left
Y = circshift(Y,size(A,2)-c+1,2)
Check it out.
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