function?desc=descriptor（keyptSOsigmmagangles）
cnt=size（keypt1）;
nbp=4;
desc=zeros（cntnbp*nbp*8）;
for?i=1:cnt
????
????o=floor（（keypt（i3）-1）/O）+1;
????s=mod（keypt（i3）-1O）+1;
????[MNtemp]=size（mag{o}）;
????sigm0=2^（（s+1）/S）*sigm;
%?????sigm0=2^（keypt（i3）/S）*sigm;
????sbp=3*sigm0;
????W=floor（sqrt（2）*sbp*（nbp+1）/2+0.5）;
????xp=keypt（i1）;
????yp=keypt（i2）;
????theta0=keypt（i4）;
????sin0=sin（theta0）;
????cos0=cos（theta0）;
????index=0;
????histo=zeros（1nbp*nbp*8）;
????for?xs?=?xp?-?min（W?xp-1）:?min（（M?-?1）?xp?+?W）
????????for?ys?=?yp?-?min（W?yp-1）?:?min（（N-1）?yp?+?W）
????????????dx=xp-xs;
????????????dy=yp-ys;
????????????if?dx^2+dy^2????????????????theta=angles{o}（xsyss）;
????????????????theta=mod（（theta-theta0）2*pi）;
????????????????nx=（

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件?????231201??2004-04-04?21:22??sift\001.jpg

?????文件?????910766??2011-04-08?15:18??sift\d2.mat

?????文件???????2814??2011-04-07?16:03??sift\descriptor.m

?????文件???????1209??2011-04-07?15:33??sift\dog.m

?????文件???????4729??2011-04-08?15:18??sift\k2.mat

?????文件???????2512??2011-04-08?15:05??sift\local_max.m

?????文件???????1697??2011-04-07?20:05??sift\match.m

?????文件????????542??2011-04-08?15:05??sift\show.m

?????文件???????1759??2011-04-08?15:18??sift\sift.m

?????文件????1092484??2000-01-01?00:00??sift\t1.JPG

?????文件????1071674??2000-01-01?00:00??sift\t2.JPG

?????目錄??????????0??2011-04-08?15:17??sift

-----------?---------??----------?-----??----

??????????????3321387????????????????????12