This is a basic image blending operation. As such, I am going to elect to do this with MIMT tools instead of native MATLAB/IPT. MIMT is available on the File Exchange:
This will give you an image where the dark areas of the two images are represented as the specified colors against a white background:
A = imread('DSC_3675.pngFFT.png');
B = imread('DSC_4062.pngFFT.png');
colorA = [255 0 0];
colorB = [0 0 255];
s = imsize(A);
if any(s ~= imsize(B))
warning('image sizes don''t match; padding')
% adjust gravity to control colocation of images
S = imstacker({A,B},'gravity','center','padding',[1 1 1]);
A = S(:,:,:,1);
B = S(:,:,:,2);
s = imsize(A);
clear S
end
% generate colored underlays
cpA = colorpict(s,colorA,'uint8');
cpB = colorpict(s,colorB,'uint8');
% colorize images
A = imblend(A,cpA,1,'screen');
B = imblend(B,cpB,1,'screen');
% combine colorized images
C = imblend(A,B,1,'multiply');
imshow(C)
If you want specified colors on a black background:
A = imread('DSC_3675.pngFFT.png');
B = imread('DSC_4062.pngFFT.png');
colorA = [255 128 0];
colorB = [0 128 255];
s = imsize(A);
if any(s ~= imsize(B))
warning('image sizes don''t match; padding')
% adjust gravity to control colocation of images
S = imstacker({A,B},'gravity','center','padding',[1 1 1]);
A = S(:,:,:,1);
B = S(:,:,:,2);
s = imsize(A);
end
% generate colored underlays
cpA = colorpict(s,colorA,'uint8');
cpB = colorpict(s,colorB,'uint8');
% colorize images
A = imblend(imcomplement(A),cpA,1,'multiply');
B = imblend(imcomplement(B),cpB,1,'multiply');
% combine colorized images
C = imblend(A,B,1,'screen');
imshow(C)
As you can tell by this awful white website background, the readability of any image depends on its surroundings.
