How to validate contrast adjusting using imadjust comparing to other contrast adjusting techniques and original image?
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I want to compare the difference between imadjust image and original image using a specific measurement o technique.Can you suggest any technique to show the differnce between original and imadjust image?
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Accepted Answer
Image Analyst
on 23 Jan 2019
You can cast the images to double then subtract them to see the differences
diffImage = double(image1) - double(image2);
imshow(diffImage, []);
impixelinfo;
You can also view the values in the workspace/variable inspector - just double-click on the variable name in the workspace panel.
More Answers (1)
DGM
on 9 Jul 2023
Edited: DGM
on 9 Jul 2023
The question and comments are vague, but this is my answer to one interpretation -- i.e. to use a graph to illustrate the transformation made to the image data. Consider a simple gamma adjustment. We should see a simple power function.
inpict = imread('tire.tif'); % original
outpict = imadjust(inpict,[0 1],[0 1],0.5); % adjusted
[xx idx] = sort(im2double(inpict(:)));
yy = im2double(outpict(idx));
plot([0 1],[0 1],':','color',[1 1 1]*0.5); hold on % reference line
plot(xx,yy) % the TF curve
xlim([0 1]); ylim([0 1])
axis square
grid on
Note that you'll only be able to draw the curve over the range represented by the images. Consider an image with a much lower dynamic range.
inpict = imread('pout.tif'); % original
outpict = imadjust(inpict,[0 1],[0 1],0.5); % adjusted
[xx idx] = sort(im2double(inpict(:)));
yy = im2double(outpict(idx));
plot([0 1],[0 1],':','color',[1 1 1]*0.5); hold on % reference line
plot(xx,yy) % the TF curve
xlim([0 1]); ylim([0 1])
axis square
grid on
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