图像SURF特征提取（SURF extraction）

图像SURF特征提取，用于图像拼接和篡改检测，注释比较详细，程序很好理解

% Example 3 Affine registration
% Load images
clear all;

I1=im2double（imread（‘TestImages/lena1.png‘））;
I2=im2double（imread（‘TestImages/lena2.png‘））;
% I1=im2double（imread（‘sky\A1.png‘））;
% I2=im2double（imread（‘sky\A2.png‘））;

% Get the Key Points
Options.upright=true;
Options.tresh=0.0001;
Ipts1=OpenSurf（I1Options）;
Ipts2=OpenSurf（I2Options）;

% Put the landmark descriptors in a matrix
D1 = reshape（[Ipts1.descriptor]64[]）;
D2 = reshape（[Ipts2.descriptor]64[]）;

% Find the best matches
err=zeros（1length（Ipts1））;
cor1=1:length（Ipts1）;
cor2=zeros（1length（Ipts1））;
for i=1:length（Ipts1）
    distance=sum（（D2-repmat（D1（:i）[1 length（Ipts2）]））.^21）;
    [err（i）cor2（i）]=min（distance）;
end

% Sort matches on vector distance
[err ind]=sort（err）;
cor1=cor1（ind）;
cor2=cor2（ind）;

% Make vectors with the coordinates of the best matches
Pos1=[[Ipts1（cor1）.y]‘[Ipts1（cor1）.x]‘];
Pos2=[[Ipts2（cor2）.y]‘[Ipts2（cor2）.x]‘];
Pos1=Pos1（1:30:）;
Pos2=Pos2（1:30:）;

% Show both images

I = zeros（[size（I11） size（I12）*2 size（I13）]）;
I（:1:size（I12）:）=I1; I（:size（I12）+1:size（I12）+size（I22）:）=I2;
figure imshow（I）; hold on;

% Show the best matches
for i=1:30;
plot（[Pos1（i2） Pos2（i2）+size（I12）]‘[Pos1（i1） Pos2（i1）]‘‘-‘）;
plot（[Pos1（i2） Pos2（i2）+size（I12）]‘[Pos1（i1） Pos2（i1）]‘‘o‘）;
end

% Calculate affine matrix
Pos1（:3）=1; Pos2（:3）=1;
M=Pos1‘/Pos2‘;

% Add subfunctions to Matlab Search path
functionname=‘OpenSurf.m‘;
functiondir=which（functionname）;
functiondir=functiondir（1:end-length（functionname））;
addpath（[functiondir ‘/WarpFunctions‘]）

% Warp the image
I1_warped=affine_warp（I1M‘bicubic‘）;

% Show the result
figure
subplot（131） imshow（I1）;title（‘Figure 1‘）;
subplot（132） imshow（I2）;title（‘Figure 2‘）;
subplot（133） imshow（I1_warped）;title（‘Warped Figure 1‘）;

 属性            大小     日期    时间   名称
----------- ---------  ---------- -----  ----
     文件        1888  2020-09-12 22:47  OpenSURF\example1006.m
     文件        1208  2020-09-12 22:47  OpenSURF\example2.m
     文件        1938  2020-09-12 22:47  OpenSURF\example3.m
     文件        3778  2020-09-12 22:47  OpenSURF\OpenSurf.m
     文件        5632  2020-09-12 22:47  OpenSURF\Thumbs.db
     文件         603  2020-09-12 22:47  OpenSURF\SubFunctions\FastHessian_BuildDerivative.m
     文件        1699  2020-09-12 22:47  OpenSURF\SubFunctions\FastHessian_buildResponselayer.m
     文件        1877  2020-09-12 22:47  OpenSURF\SubFunctions\FastHessian_buildResponseMap.m
     文件        2353  2020-09-12 22:47  OpenSURF\SubFunctions\FastHessian_getIpoints.m
     文件         455  2020-09-12 22:47  OpenSURF\SubFunctions\FastHessian_getLaplacian.m
     文件         450  2020-09-12 22:47  OpenSURF\SubFunctions\FastHessian_getResponse.m
     文件        2478  2020-09-12 22:47  OpenSURF\SubFunctions\FastHessian_interpolateExtremum.m
     文件        1680  2020-09-12 22:47  OpenSURF\SubFunctions\FastHessian_isExtremum.m
     文件         738  2020-09-12 22:47  OpenSURF\SubFunctions\FastHessian_Responselayer.m
     文件         791  2020-09-12 22:47  OpenSURF\SubFunctions\IntegralImage_BoxIntegral.m
     文件         494  2020-09-12 22:47  OpenSURF\SubFunctions\IntegralImage_HaarX.m
     文件         556  2020-09-12 22:47  OpenSURF\SubFunctions\IntegralImage_HaarY.m
     文件         796  2020-09-12 22:47  OpenSURF\SubFunctions\IntegralImage_IntegralImage.m
     文件        1089  2020-09-12 22:47  OpenSURF\SubFunctions\PaintSURF.m
     文件        1554  2020-09-12 22:47  OpenSURF\SubFunctions\SurfDescriptor_DecribeInterestPoints.m
     文件        3636  2020-09-12 22:47  OpenSURF\SubFunctions\SurfDescriptor_GetDescriptor.m
     文件        2921  2020-09-12 22:47  OpenSURF\SubFunctions\SurfDescriptor_GetOrientation.m
     文件       75288  2020-09-12 22:47  OpenSURF\TestImages\043.png
     文件       81918  2020-09-12 22:47  OpenSURF\TestImages\044.png
     文件       15904  2020-09-12 22:47  OpenSURF\TestImages\fish1.png
     文件       15428  2020-09-12 22:47  OpenSURF\TestImages\fish2.png
     文件      239755  2020-09-12 22:47  OpenSURF\TestImages\lena1.png
     文件      211716  2020-09-12 22:47  OpenSURF\TestImages\lena2.png
     文件       19555  2020-09-12 22:47  OpenSURF\TestImages\lena20.jpg
     文件      113463  2020-09-12 22:47  OpenSURF\TestImages\lena21.jpg
     文件        5296  2020-09-12 22:47  OpenSURF\TestImages\test.png
............此处省略6个文件信息