SIFT.rar_6YK9_SIFT特征_sift特征提取_sift特征点提取_特征提取

function [des,loc]=zoo_sift(im) [row,col]=size(im); f=fopen('tmp.pgm','w'); if f==-1 error('Could not create file tmp.pgm.'); end fprintf(f, 'P5\n%d\n%d\n255\n', col, row); fwrite(f,im','uint8'); fclose(f); if isunix command = '!./sift '; else command = '!siftWin32 '; end command = [command ' <tmp.pgm >tmp.key']; eval(command); g=fopen('tmp.key','r'); if g==-1 error('Could not open file tmp.key.'); end [header,cnt]=fscanf(g,'%d %d',[1 2]); if cnt~=2 error('Invalid keypoint file beginning.'); end num=header(1); len=header(2); if len~=128 error('Keypoint descriptor length invalid (should be 128).'); end loc=double(zeros(num,4)); des=double(zeros(num,128)); for k=1:num [vector,cnt]=fscanf(g, '%f %f %f %f', [14]); if cnt~=4 error('Invalid keypoint file format'); end loc(k,:)=vector(1,:); [descrip, count] = fscanf(g, '%d', [1 len]); if (count ~= 128) error('Invalid keypoint file value.'); end descrip = descrip / sqrt(sum(descrip.^2)); des(k, :) = descrip(1, :); end fclose(g); for k=1:size(des,1) des(k,:)=des(k,:)/sum(des(k,:)); end delete tmp.key tmp.pgm