function [resultImage, permuteParameter] = hb_imageScramble(inputImage, nSection, showOption) % this matlab function returns scrambled matrix of input image, [nSection+1 by nSection+1] % example -> image scramble into 2 by 2 grid (without image plot) % >> resultImage = hb_imageScramble(inputImage, 2, false); % example -> image scramble into 4 by 4 grid (with image plot) % >> resultImage = hb_imageScramble(inputImage, 4, true); % initial commit : 20160326 % hiobeen@yonsei.ac.kr % key word : image scramble matlab
if nargin < 3 showOption = false; end if nSection == 1 resultImage = inputImage; if showOption subplot(1,2,1); imshow(inputImage); title('input image'); subplot(1,2,2); imshow(resultImage); title(['scrambled image (' num2str(nSection) ' by ' num2str(nSection) ')']); end return; end [nRow, nCol, nDim] = size(inputImage);
rowSpace = floor(linspace( 1, nRow , nSection+1 )); % make mosaic indicies colSpace = floor(linspace( 1, nCol , nSection+1 ));
rowSpace(end) = nRow; colSpace(end) = nCol; % should be equal to original image size min_possibleSize = [ max(diff(rowSpace)), max(diff(colSpace)) ];
mosaics = cell([1,(nSection)^2]); % section images into {N x N}, and temporally store into the cell 'mosaics' permuteParameter = randperm( (nSection)^2 ); % make random indexing parameter
% Split image into cells (with random order) mosaic_nAppend = 0; for rowIdx = 1:length(rowSpace)-1 for colIdx = 1:length(rowSpace)-1 mosaic_nAppend = mosaic_nAppend+1; mosaics{1,permuteParameter(mosaic_nAppend)} = imresize(inputImage(... rowSpace(rowIdx):rowSpace(rowIdx+1)-1,... colSpace(colIdx):colSpace(colIdx+1)-1, :), min_possibleSize); end end
% CAT image, step 1 (integrate by rows) cat_row = cell( [1, nSection] ); cat_row_nAppend = 0; for cellIdx = 1:length(mosaics) if mod(cellIdx, nSection) == 1 cat_row_nAppend = cat_row_nAppend+1; end cat_row{1, cat_row_nAppend} = cat(1,cat_row{1, cat_row_nAppend},... mosaics{1,cellIdx}); end
% CAT image, step 2 (integrate by columns) cat_col = []; for cellIdx = 1:length(cat_row) cat_col = cat(2, cat_col, cat_row{1,cellIdx}); end
% CAT image, step 3 (integrate by color dimension) if nDim > 1 resultImage = []; for dimIdx = 1:nDim resultImage = cat(3, resultImage, imresize(squeeze(cat_col(:,:,dimIdx)), [nRow, nCol])); end else resultImage = imresize(cat_col, [nRow, nCol]); end
if showOption subplot(1,2,1); imshow(inputImage); title('input image'); set(gca, 'YDir', 'normal'); subplot(1,2,2); imshow(resultImage); title(['scrambled image (' num2str(nSection) ' by ' num2str(nSection) ')']); set(gca, 'YDir', 'normal'); end
return