基于BP神经网络的手写数字识别matlab实现

function Feature = FeatureExtract(img,opts) %---------------------- Introduction --------------------% % input: % img: image list % opts: parameters % output: % Feature: features that extracted from images % % describe: use the patch that has a fixed size to scanf the image;(patch as a point) % then sum the pixel value that in a patch; % compute the percent of black pixel in patch as an element of feature. %---------------------------------------------------------% patch = opts.patch; width = opts.width; height = opts.height; nImg = length(img); column = width/patch(1); row = height/patch(2); area = patch(1)*patch(2); PixPercent = zeros(row*column,1); Feature = zeros(row*column,nImg); %----------------------------------------- Feature Extraction -----------------------------------------% for k = 1:length(img); bw = im2bw( img{k},graythresh(img{k}) ); reImg = imresize( bw,[height,width] ); for i = 1:row for j = 1:column Atemp = sum( reImg( ( ( i*patch(2)-(patch(2)-1) ):(i*patch(2)) ) , ( ( j*patch(1)-(patch(1)-1) ):(j*patch(1)) ) ) ); PixPercent( (i-1)*column + j ) = sum( Atemp ); end end PixPercent = ( (area-PixPercent)/area ); Feature(:,k) = PixPercent; end %----------------------------------------------- End ---------------------------------------------------% end