idamnjanovic@10: function data=Pierre_Problem(src, trg, blocksize, dictsize);
idamnjanovic@10: %%% Generate Pierre Problem
idamnjanovic@21: %
idamnjanovic@21: %   Centre for Digital Music, Queen Mary, University of London.
idamnjanovic@21: %   This file copyright 2010 Ivan Damnjanovic.
idamnjanovic@21: %
idamnjanovic@21: %   This program is free software; you can redistribute it and/or
idamnjanovic@21: %   modify it under the terms of the GNU General Public License as
idamnjanovic@21: %   published by the Free Software Foundation; either version 2 of the
idamnjanovic@21: %   License, or (at your option) any later version.  See the file
idamnjanovic@21: %   COPYING included with this distribution for more information.
idamnjanovic@10: %
idamnjanovic@10: %   Pierre_Problem is a part of the SMALLbox and generates the problem
idamnjanovic@10: %   suggested by Professor Pierre Vandergheynst on the SMALL meeting in 
idamnjanovic@10: %   Villars.
idamnjanovic@10: %   The function takes as an input:
idamnjanovic@10: %   -   src - source image matrix (if not present function promts user for 
idamnjanovic@10: %             an image file) ,
idamnjanovic@10: %   -   trg - target image matrix (if not present function promts user for 
idamnjanovic@10: %             an image file) ,
idamnjanovic@10: %   -   blocksize - block (patch) vertical/horizontal dimension (default 8),
idamnjanovic@10: %   -   dictsize - dictionary size (default - all patches from target
idamnjanovic@10: %   image).
idamnjanovic@10: %
idamnjanovic@10: %   The output of the function is stucture with following fields:
idamnjanovic@10: %   -   srcname - source image name,
idamnjanovic@10: %   -   imageSrc - source image matrix,
idamnjanovic@10: %   -   trgname - target image name,
idamnjanovic@10: %   -   imageTrg - Target image matrix,
idamnjanovic@10: %   -   A - dictonary with patches from the source image,
idamnjanovic@10: %   -   b - measurement matrix (i.e. patches from target image to be
idamnjanovic@10: %           represented in dictionary A,
idamnjanovic@10: %   -   m - size of patches (default 25),
idamnjanovic@10: %   -   n - number of patches to be represented,
idamnjanovic@10: %   -   p - dictionary size,
idamnjanovic@10: %   -   blocksize - block size (default [5 5]),
idamnjanovic@10: %   -   maxval - maximum value (default - 255)
idamnjanovic@10: %   -   sparse - if 1 SMALL_solve will keep solution matrix in sparse form,
idamnjanovic@10: %                due to memory constrains.
idamnjanovic@10: 
idamnjanovic@10: %% prompt user for images %%
idamnjanovic@10: 
idamnjanovic@28: %   ask for source file name
idamnjanovic@10: 
idamnjanovic@10: TMPpath=pwd;
idamnjanovic@10: FS=filesep;
idamnjanovic@10: if ~ exist( 'src', 'var' ) || isempty(src)
idamnjanovic@10: [pathstr1, name, ext, versn] = fileparts(which('SMALLboxSetup.m'));
idamnjanovic@10: cd([pathstr1,FS,'data',FS,'images']);
idamnjanovic@10: [filename,pathname] = uigetfile({'*.png;'},'Select a source image');
idamnjanovic@10: [pathstr, name, ext, versn] = fileparts(filename);
idamnjanovic@10: data.srcname=name;
idamnjanovic@10: src = imread(filename);
idamnjanovic@10: src = double(src);
idamnjanovic@10: end;
idamnjanovic@10: 
idamnjanovic@28: %   ask for target file name
idamnjanovic@10: 
idamnjanovic@10: if ~ exist( 'trg', 'var' ) || isempty(trg)
idamnjanovic@10: [filename,pathname] = uigetfile({'*.png;'},'Select a target image');
idamnjanovic@10: [pathstr, name, ext, versn] = fileparts(filename);
idamnjanovic@10: data.trgname=name;
idamnjanovic@10: trg = imread(filename);
idamnjanovic@10: trg = double(trg);
idamnjanovic@10: end;
idamnjanovic@10: cd(TMPpath);
idamnjanovic@10: 
idamnjanovic@10: %% set parameters %%
idamnjanovic@10: 
idamnjanovic@10: maxval = 255;
idamnjanovic@10: if ~ exist( 'blocksize', 'var' ) || isempty(blocksize),blocksize = 5;end
idamnjanovic@10: 
idamnjanovic@10: if ~ exist( 'dictsize', 'var' ) || isempty(dictsize),
idamnjanovic@10:     dictsize = (size(src,1)-blocksize+1)*(size(src,2)-blocksize+1);
idamnjanovic@10:     patch_idx=1:dictsize;
idamnjanovic@10: else  
idamnjanovic@10:     num_blocks_src=(size(src,1)-blocksize+1)*(size(src,2)-blocksize+1);
idamnjanovic@10:     patch_idx=1:floor(num_blocks_src/dictsize):dictsize*floor(num_blocks_src/dictsize);
idamnjanovic@10: end
idamnjanovic@10: 
idamnjanovic@10: p = ndims(src);
idamnjanovic@10: if (p==2 && any(size(src)==1) && length(blocksize)==1)
idamnjanovic@10:   p = 1;
idamnjanovic@10: end
idamnjanovic@10: 
idamnjanovic@10: 
idamnjanovic@10: % blocksize %
idamnjanovic@10: if (numel(blocksize)==1)
idamnjanovic@10:   blocksize = ones(1,p)*blocksize;
idamnjanovic@10: end
idamnjanovic@10: %%
idamnjanovic@10: %% create dictionary data %%
idamnjanovic@10: 
idamnjanovic@10: S=im2col(src,blocksize,'sliding');
idamnjanovic@10: 
idamnjanovic@10: for j= 1:size(S,2)
idamnjanovic@10:     S(:,j)=S(:,j)./norm(S(:,j));
idamnjanovic@10: end
idamnjanovic@10: 
idamnjanovic@10: %% create measurement matrix %%
idamnjanovic@10: 
idamnjanovic@10: T=im2col(trg,blocksize, 'distinct');
idamnjanovic@10: 
idamnjanovic@10: %% output structure %%
idamnjanovic@10: 
idamnjanovic@10: data.imageSrc = src;
idamnjanovic@10: data.imageTrg = trg;
idamnjanovic@10: data.A = S(:,patch_idx);
idamnjanovic@10: data.b = T;
idamnjanovic@10: data.m = size(T,1);
idamnjanovic@10: data.n = size(T,2);
idamnjanovic@10: data.p = size(data.A,2);
idamnjanovic@10: data.blocksize=blocksize;
idamnjanovic@10: data.maxval=maxval;
idamnjanovic@10: 
idamnjanovic@28: %   keep coefficients matrix in sparse form and do not convert it to full.
idamnjanovic@28: %   geting around out of memory problem when converting big matrix from
idamnjanovic@28: %   sparse to full... (check SMALL_solve function)
idamnjanovic@10: data.sparse=1;
idamnjanovic@10: 
idamnjanovic@10: