Splitting Images?

Hi, I have a question here.

Take for example an image of size n by m. What I want is to split the images into 4 similar quadrants as follows: http://www.flickr.com/photos/jokerzy89/5859808219/ Next, I want to swap the following. (1)A and C (2) B and D, then display the final result as a new image.

Can someone please help? Thank you!

[Jason]

My guess is that first you need to read the size of the image, then proceed to define the four quadrants. Something like this:

A = image(1:n/2, 1:m/2);

B = image(1:n/2, m/2:m);

C = image(n/2:n, 1:m/2);

D = image(n/2:n, m/2:m);

Am I right?

[Sean de Wolski]

A is B in the above. It's not right because row/cols: n/2 , m/2 will each appear twice and what would happen if you had an off image say: 255x255

255/2 = ? - a non-integer index.

[Jason]

Thank you, that is why the floor function comes into picture.

[Sean de Wolski]

yes, you could also use ceil.

Answer 1

[Sean de Wolski]

swap1324 = @(x)([x((floor(size(x,1)/2)+1):end,(floor(size(x,2)/2)+1):end) x((floor(size(x,1)/2)+1):end,1:floor(size(x,2)/2)); x(1:floor(size(x,1)/2),(floor(size(x,1)/2)+1):end) x(1:floor(size(x,1)/2),1:floor(size(x,2)/2))]);

I = imread('cameraman.tif'); %sample image
I2 = swap1324(I);

imtool(I2)

Obviously the above should be broken down into it's own function that doesn't have to repeat the function floor(size(stuff))) over and over again.

[Jason]

That was fast, and it was exactly what I needed, thank you, Sean!