Clash Royale CLAN TAG#URR8PPP

Divide images into four equal images

How to divide a set of images which (512*512) into four equal images; each is 256*256 and this repeated for 150 images ?

512*512

256*256

150

I = imread(['file',num2str(i),'.tif']);
I1 = I(1:size(I,1)/2,1:size(I,2)/2,:);
I2 = I(size(I,1)/2+1:size(I,1),1:size(I,2)/2,:);
I3 = I(1:size(I,1)/2,size(I,2)/2+1:size(I,2),:);
I4 = I(size(I,1)/2+1:size(I,1),size(I,2)/2+1:size(I,2),:);


1 Answer
1

I don't have matlab at hand, so there might be some mistakes, but the idea will hold:

You have to choose how you will store your split up images. For example, you can use cells. I'll assume your images are called file1.tif, file2.tif and so on.

num_imgs = 150; %The total ammount of images you have
cropped_imgs = cell(1,num_imgs) %create empty 1 by 150 cell

%create a for loop to repeat over all images
for k in 1:num_imgs:
I = imread(['file',num2str(k),'.tif']); %load your image
sz = size(I,1)/2; %get half the size, assuming it's a square image
%split images and pack into 1 by 4 cell
cropped_imgsk = I(1:sz, 1:sz), I(1:sz, sz+1:end), I(sz+1:end, 1:sz), I(sz+1:end, sz+1:end)
end


Now you can access them by doing something like cropped_imgs1272 for the second crop of image number 127. Hope this helps, but seriously, research a bit before posting a question. Maybe a better way to store the images would be in a 150 by 4 cell and access them by cropped_imgs127,2, but that depends on what you like.

cropped_imgs1272

cropped_imgs127,2

EDIT: If you were asking how to split images in a less explicit way, you could try and use imcrop with a given rectangle and move the rectangle:

imcrop

num_imgs = 150; %The total ammount of images you have
cropped_imgs = cell(4,num_imgs) %create empty 4 by 150 cell

%create a for loop to repeat over all images
for k in 1:num_imgs:
I = imread(['file',num2str(k),'.tif']); %load your image
sz = size(I)/2; %get half the size, assuming it's a square image
%split images and pack into 1 by 4 cell
cropped_imgsk,1 = imcrop(I,[0,0,sz]);
cropped_imgsk,2 = imcrop(I,[sz(1),0,sz]);
cropped_imgsk,3 = imcrop(I,[0,sz(1),sz]);
cropped_imgsk,4 = imcrop(I,[sz,sz]);
end


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