function [out] = crop_image(img, patch_size, stride, factor, file_name)

% Normalization for CAVE dataset
%img = double(img)./65535;
% Normalization for Pavia Center dataset
%img = double(img)./8000;
% Normalization for Chikusei dataset
img = double(img);

[H, W, C] = size(img);
p = patch_size;
pat_col_num = 1:stride:(H - p + 1);
pat_row_num = 1:stride:(W - p + 1);
total_num = length(pat_col_num) * length(pat_row_num);
index = 1;

% crop a single patch from whole image
for i=1:length(pat_col_num)
    for j = 1:length(pat_row_num)
        up = pat_col_num(i);
        down = up + p - 1;
        left = pat_row_num(j);
        right = left + p - 1;
        gt = img(up:down, left:right, :);
        ms = single(imresize(gt, factor));
        ms_bicubic = single(imresize(ms, 1/factor));
        gt = single(gt);
        file_path = strcat('/Users/miaoyuchun/Desktop/superx2/dataset/Houston_x2/trains_solely/block_', file_name, '_', num2str(index), '.mat');
%         file_path = strcat('./dataset/Pavia_x2/trains/block_', file_name, '_', num2str(index), '.mat');
%       file_path = strcat('./dataset/Chikusei_x2/trains/block_', file_name, '_', num2str(index), '.mat');
%       file_path = strcat('./dataset/Chikusei_x8/trains/block_', file_name, '_', num2str(index), '.mat');
        save(file_path,'gt','ms','ms_bicubic','-v6');
        index = index + 1;
    end
end
out = total_num;
end