MATLAB Answers

How to show the image slice from the below example?

40 views (last 30 days)
blues
blues on 26 Feb 2021
Commented: Walter Roberson on 28 Feb 2021
Hello, I want to show the image slice from the below example, where CT and SPECT both are image array with the same width, size and spacing.
% This is a part of the code
% Visualize the CT and SPECT together
for m = 1:199
CT_img = new_CT(:,:,m);
SPECT_img = SPECT(:,:,m);
final_img = imfuse(CT_img, SPECT_img);
% Visualize CT and SPECT together
imshow(final_img, [-800 1000]);
end
% Now, I want to see the overlapped slices one by one, so I want somethig like:
show_20th_slice = imshow(final_img(:,:,20)) %...>> but this says: "Index in position 3 exceeds array bounds (must not exceed 3)."
How can I do this?

Accepted Answer

Walter Roberson
Walter Roberson on 26 Feb 2021
% This is a part of the code
% Visualize the CT and SPECT together
for m = 1:199
CT_img = new_CT(:,:,m);
SPECT_img = SPECT(:,:,m);
final_img(:,:,:,m) = imfuse(CT_img, SPECT_img);
% Visualize CT and SPECT together
imshow(final_img(:,:,:,m), [-800 1000]);
end
% Now, I want to see the overlapped slices one by one, so I want somethig like:
show_20th_slice = imshow(final_img(:,:,:,20))
I am not sure at the moment why you are getting back color images instead of grayscale, but your error message would have been different if you were getting back grayscale.
  4 Comments
Walter Roberson
Walter Roberson on 28 Feb 2021
im1 = imread('cameraman.tif');
im2 = rgb2gray(imread('flamingos.jpg'));
im2 = imresize(im2, size(im1));
fused_by_function = imfuse(im1, im2);
fused_manually = cat(3, im2, im1, im2);
subplot(2,1,1);
imshow(fused_by_function);
title('imfuse()')
subplot(2,1,2)
imshow(fused_manually);
title('manual fuse')
max(abs(double(fused_by_function(:)) - double(fused_manually(:))))
ans = 12
We can see from this that imfuse(A,B) is effectively the same as putting B into the red and blue panes and A into the green pane.
And that in turn tells us that using a different colormap would not be easy, because it is not really "calculating" a color for each pixel, and is more "just letting it happen". So you would need a quite different approach.
Perhaps something like:
alpha = 0.7;
cmap1 = gray(256);
cmap2 = jet(256);
im1rgb = ind2rgb(im1, cmap1);
im2rgb = ind2rgb(im2, cmap2);
blended = alpha * im1rgb + (1-alpha) * im2rgb;
figure()
subplot(3,1,1)
imshow(im1rgb); title('image1 recolored');
subplot(3,1,2);
imshow(im2rgb); title('image2 recolored');
subplot(3,1,3);
imshow(blended); title('blended')

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by