Matlab：如何从4-D矩阵进行绘图

Question

I have a 4-d matrix contains 1000 pictures. The shape of matrix is 1000*32*32*3 (1000 is the number of pictures, 32*32 is a 2-d pixel values, 3 is RGB-3 channels).

I was wondering how to display one channel 32*32 values for a picture? or 3 channels 32*32*3?

and can matlab plot the 32*32? or 3 pictures for 3 channels of 32*32?

Answer 1

In general, you use the imshow command for showing an image, either single-channel (grayscale) or multi-channel (color). In case, you have multiple images stored in the way, you describe, you need to index a specific (grayscale or color) image (or color channel), and possibly need the squeeze command to remove dimensions of length 1, which might cause problems with imshow .

Please see the following code snippet using some mock-up data:

% Mock-up data.
A = uint8(round(255 * rand(1000, 32, 32, 3)));

% Select I-th image.
I = 25;

figure(1);

% Show I-th RGB image.
subplot(2, 2, 1);
imshow(squeeze(A(I, :, :, :)));

% Show I-th red channel image.
subplot(2, 2, 2);
imshow(squeeze(A(I, :, :, 1)));

% Show I-th green channel image.
subplot(2, 2, 3);
imshow(squeeze(A(I, :, :, 2)));

% Show I-th blue channel image.
subplot(2, 2, 4);
imshow(squeeze(A(I, :, :, 3)));

Output: