%--------------------------------------------

% USAGE:

% % % This example shows the following functions are equivalent:

% % % extract_patches_lex_col <=> Get_patches_2_lex_col

% % % insert_patches_lex_col <=> insert_patches_Get_patches_2_lex_col

% % %

% % im=im2double(imread('cameraman.tif'));

% % [R,C]=size(im);

% % ps=[8 8];

% % step=[1 1];

% % tic

% % %

% % % X=extract_patches_lex_col(im,ps,step);

% % X=Get_patches_2_lex_col(im,ps);

% % %

% % % im2=insert_patches_lex_col(X,R,C,ps,step);

% % im2=insert_patches_Get_patches_2_lex_col(X,R,C,ps);

% % %

% % time_extraction_insertion=toc

% % figure,imshow(im2)

%--------------------------------------------

% Ashkan

function [Px] = Get_patches_2_lex_col( im, ps )

% this function belongs to the ASDS package. The algorithm that was

% presented by Weishong Dong, 2011.

% "Image Deblurring and Super-resolution by Adaptive Sparse Domain

% Selection and Adaptive Regularization", TIP 2011

% Also, An slightly modified version of it is used by the SBSDI algorithm

% of Fang et al. 2013.

%

% I modified it to work similar to the Dr. Fang's implementation.

% Ashkan

% Px:blocks that are extracted from the original image

% im: a grayscale image

% ps: patch size (e.g. ps=[4,4])

[h,w] = size(im);

N = h-ps(1)+1;

M = w-ps(2)+1;

s = 1;

r = 1:s:N;

r = [r r(end)+1:N];

c = 1:s:M;

c = [c c(end)+1:M];

L = length(r)*length(c);

Px = zeros(ps(1)*ps(2), L, 'single');

k = 0;

for i = 1:ps(1)

for j = 1:ps(2)

k = k+1;

% the (i,j)th-pixel of all the patches are extracted

blk = im(r-1+i,c-1+j);

Px(k,:) = blk(:)';

end

end