how to divide an image diagonally into two equal part where the image size is [168 300 3]?

divide the image diagonally into two part where the image size is [168 300 3]. how can it be done?

Answer 1

[Guillaume]

A simple way would be to use triu and tril. You could do it like this:

UpperTriangle = cat(3, triu(img(:, :, 1), triu(img(:, :, 2), triu(img(:, :, 3));
LowerTriangle = cat(3, tril(img(:, :, 1), triu(iml(:, :, 2), tril(img(:, :, 3));

Or like this:

mask = true(size(img, 1), size(img ,2)); 
UpperTriangle = img(repmat(triu(mask), [1 1 3]));
LowerTriangle = img(repmat(tril(mask), [1 1 3]));

[Soumyadip Chakraborty]

mask = true(size(img, 1), size(img ,2)); 
UpperTriangle = img(repmat(triu(mask), [1 1 3]);
LowerTriangle = img(repmat(tril(mask), [1 1 3]);

this is not working. showing error:

??? Subscript indices must either be real positive integers or logicals.

[Guillaume]

I forgot a closing brackets for UpperTriangle and LowerTriangle, but otherwise the code works. I don't understand how you can get that error message since mask is logical (that's what true returns).

[Image Analyst]

Did you see my full demo in your duplicate question, with pictures and everything, where I show the masked image: http://www.mathworks.com/matlabcentral/answers/210394-how-to-divide-an-image-diagonally-into-two-part#answer_175855

[Soumyadip Chakraborty]

yes,i have seen it and also run it clc; close all; workspace; format long g; format compact; fontsize=20; im=imread('12.jpg'); subplot(3,1,1); imshow(im,[]); title('org im','Fontsize',fontsize); set(gcf,'Units','Normalized', 'OuterPosition',[0 0 1 1]); set(gcf, 'Name', 'picture', 'NumberTitle', 'Off') upperPixelImage = triu(im); subplot(3, 1, 2); imshow(upperPixelImage, []); title('Upper Triangle', 'FontSize', fontSize); mask = triu(ones(size(im))) > 0; upperList = upperPixelImage(mask); lowerPixelImage = tril(im); subplot(3, 1, 3); imshow(lowerPixelImage, []); title('Lower Triangle', 'FontSize', fontSize); mask = tril(ones(size(im))) > 0; lowerList = lowerPixelImage(mask);

error : ??? Error using ==> triu First input must be 2D.

Error in ==> diag at 13 upperPixelImage = triu(im);

only the original image showing not the others

if the first input must be 2D, then what has to be done in case of 3D?

[Soumyadip Chakraborty]

thank u very much, it worked.