How can I crop the image at a particular location each time?

I have multiple rbg images. I want to analyze them for pixel calculation. But I only want a part of it. How can I crop all the images at the exact same location?

Answer 1

[yanqi liu]

yes，sir，just use imcrop can get target area image，if multi image do not have same size，may be use width and height rate，such as

clc; clear all; close all;
files = {'cameraman.tif', 'football.jpg', 'rice.png'};
rect = [0.2 0.3 0.4 0.3];
for i = 1 : length(files)
    % get image
    imi = imread(files{i});
    sz = size(imi);
    % get rect
    recti = rect .* [sz(2) sz(1) sz(2) sz(1)];    
    % crop image
    imi2 = imcrop(imi, round(recti));
    figure;
    subplot(1,2,1); imshow(imi, []);
    hold on; rectangle('position', recti, 'EdgeColor', 'r', 'LineWidth', 2)
    subplot(1,2,2); imshow(imi2, []);
end

Answer 2

[HighPhi]

Your rgb images are an X x Y x 3 array,

where, visually, X is actually image height and Y is actually image width

If you imaging that the top left corner of your image is 0,0

you can get another smaller cropped area via:

rgb2 = rgb1(X1:X2, Y1:Y2, :);

Answer 3

[David Hill]

Your rbg image is just a matrix. Just index into the matrix at the location you want.

x=uint8(randi(255,1000,1000,3));
imshow(x(10:10,50:80,:));