sift

I = imread('image.jpg');

I = single(rgb2gray(I));

O=imread('image2.jpg');

O = single(rgb2gray(O));

P=imread('image4.jpg');

P = single(rgb2gray(P));

Q = imread('image3.jpg');

Q = single(rgb2gray(Q));

[fa, da] = vl_sift(I);

[fb, db] = vl_sift(O);

[fc, dc] = vl_sift(P);

[fd, dd] = vl_sift(P);

%matches 返回二维的位置向量

%scores 返回距离
t0 = cputime;

tic;

[matches1, scores1] = vl_ubcmatch(da, db);

[matches2, scores2] = vl_ubcmatch(da, dc);

[matches3, scores3] = vl_ubcmatch(dd, dd);

toc;

t0=clock;

time = etime(clock,t0);

欧式平方距离(Squared Euclidean distance)测距方法