OpenCV2.4.13 SIFT算法

来源：互联网发布：淘宝商品被管控下架了编辑：程序博客网时间：2024/06/05 19:31

void CSIFTMatchingDlg::ImageShift()
{
         ////初始化模块，使用SIFT或SURF时用到(注意需要包含头文件nonfree.hpp
         cv::initModule_nonfree();

         cv::MathTemplateImage = cv::imread("E:\\机器视觉测试样本图像\\201512\\电阻\\1-1.bmp");
         cv::MathSrcImage = cv::imread("E:\\机器视觉测试样本图像\\201512\\电阻\\20151113-092950078-BW.bmp");

         //检测特征点
         cv::Ptr<cv::FeatureDetector>featureDetector = cv::FeatureDetector::create("SIFT");
         if(featureDetector->empty())
         {
                   AfxMessageBox("特征侦测器为空");
                   return;
         }

         cv::vector<cv::KeyPoint>hTemplateKeyPoint, hSrcKeyPoint;
         featureDetector->detect(hTemplateImage,hTemplateKeyPoint);
         featureDetector->detect(hSrcImage,hSrcKeyPoint);

         //根据特征点计算特征描述子矩阵，即特征向量矩阵
         cv::Ptr<cv::DescriptorExtractor>descriptorExtractor = cv::DescriptorExtractor::create("SIFT");
         if(descriptorExtractor->empty())
         {
                   AfxMessageBox("特征向量生成器为空");
                   return;
         }
         cv::MathTemplateDescriptors, hSrcTemplateDescriptors;
         descriptorExtractor->compute(hTemplateImage,hTemplateKeyPoint, hTemplateDescriptors);
         descriptorExtractor->compute(hSrcImage,hSrcKeyPoint, hSrcTemplateDescriptors);

         //特征匹配
         cv::Ptr<cv::DescriptorMatcher>descriptor_matcher = cv::DescriptorMatcher::create("BruteForce");

         cv::vector<cv::DMatch>vdMatches;
         descriptor_matcher->match(hTemplateDescriptors,hSrcTemplateDescriptors, vdMatches);

         ////筛选匹配结果
         intnMinDis = 100, nMaxDis = 0;
         for(int i = 0; i < vdMatches.size(); i++)
         {
                   if(nMinDis > vdMatches[i].distance)
                            nMinDis= vdMatches[i].distance;
                   if(nMaxDis < vdMatches[i].distance)
                            nMaxDis= vdMatches[i].distance;
         }

         cv::vector<cv::DMatch>vdGoodMatches;
         for(int i = 0; i < vdMatches.size(); i++)
         {
                   if(vdMatches[i].distance < nMaxDis * 0.3)
                            vdGoodMatches.push_back(vdMatches[i]);
         }

         //画出匹配结果
         cv::MatmMatchResult;
         cv::drawMatches(hTemplateImage,hTemplateKeyPoint, hSrcImage, hSrcKeyPoint, vdGoodMatches, mMatchResult,cv::Scalar::all(-1), CV_RGB(0, 255, 0),       cv::Mat(),cv::DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS);

         imshow("Matchingresult",mMatchResult);

}

代码解析

1、FeatureDetector

2D图像特征检测基类

classCV_EXPORTSFeatureDetector

{

public:

virtual~FeatureDetector();

void detect(const Mat& image, vector<KeyPoint>& keypoints,

const Mat& mask=Mat() ) const;

void detect(const vector<Mat>& images,

vector<vector<KeyPoint>>& keypoints,

const vector<Mat>& masks=vector<Mat>() )const;

virtualvoidread(const FileNode&);

virtualvoid write(FileStorage&)const;

static Ptr<FeatureDetector> create( const string& detectorType );

protected:

...

};

不能直接定义生成，只能通过调用create生成。

1.1 FeatureDetector::create

创建特征检测变量，例如：cv::Ptr<cv::FeatureDetector> featureDetector =cv::FeatureDetector::create("SIFT");

可传入参数如下：

"FAST" – FastFeatureDetector

"STAR" – StarFeatureDetector

"SIFT" – SIFT (nonfree module)

"SURF" – SURF (nonfree module)

"ORB" – ORB

"BRISK" – BRISK

"MSER" – MSER

"GFTT" – GoodFeaturesToTrackDetector

"HARRIS" – GoodFeaturesToTrackDetector withHarris detector enabled

"Dense" – DenseFeatureDetector

"SimpleBlob" – SimpleBlobDetector

1.2 FeatureDetector::detect

检测图像或者图像集中的特征点

2 DescriptorExtractor

图像特征点计算描述符抽象基类。

classCV_EXPORTS DescriptorExtractor

public:

    virtual~DescriptorExtractor();

    void compute( const Mat& image, vector<KeyPoint>& keypoints,

                  Mat& descriptors ) const;

    void compute( const vector<Mat>& images, vector<vector<KeyPoint>>& keypoints,

                  vector<Mat>& descriptors ) const;

    virtualvoidread(const FileNode& );

    virtualvoid write( FileStorage& ) const;

    virtualint descriptorSize() const=0;

    virtualint descriptorType() const=0;

    static Ptr<DescriptorExtractor> create( const string& descriptorExtractorType );

protected:

...

};

不能直接定义生成，只能通过调用create生成。

2.1 DescriptorExtractor::create

创建描述符生成类，例如：cv::Ptr<cv::DescriptorExtractor>descriptorExtractor = cv::DescriptorExtractor::create("SIFT");

可传入参数如下：

"SIFT" – SIFT

"SURF" – SURF

"BRIEF" – BriefDescriptorExtractor

"BRISK" – BRISK

"ORB" – ORB

"FREAK" – FREAK

2.2 DescriptorExtractor::compute

计算特征点的描述符

3. DescriptorMatcher

匹配特征向量的抽象类

classDescriptorMatcher

public:

    virtual~DescriptorMatcher();

    virtualvoidadd(const vector<Mat>& descriptors );

    const vector<Mat>& getTrainDescriptors() const;

    virtualvoidclear();

    bool empty() const;

    virtualbool isMaskSupported() const=0;

    virtualvoidtrain();

/*

     * Group of methods to match descriptors from an image pair.

*/

    void match( const Mat& queryDescriptors, const Mat& trainDescriptors,

                vector<DMatch>& matches, const Mat& mask=Mat() ) const;

    void knnMatch( const Mat& queryDescriptors, const Mat& trainDescriptors,

                   vector<vector<DMatch>>& matches, int k,

                   const Mat& mask=Mat(),bool compactResult=false ) const;

    void radiusMatch( const Mat& queryDescriptors, const Mat& trainDescriptors,

                      vector<vector<DMatch>>& matches, float maxDistance,

                      const Mat& mask=Mat(),bool compactResult=false ) const;

/*

     * Group of methods to match descriptors from one image to an image set.

*/

    voidmatch(const Mat& queryDescriptors, vector<DMatch>& matches,

                const vector<Mat>& masks=vector<Mat>() );

    voidknnMatch(const Mat& queryDescriptors, vector<vector<DMatch>>& matches,

                   int k, const vector<Mat>& masks=vector<Mat>(),

                   bool compactResult=false );

    voidradiusMatch(const Mat& queryDescriptors, vector<vector<DMatch>>& matches,

                      float maxDistance, const vector<Mat>& masks=vector<Mat>(),

                      bool compactResult=false );

    virtualvoidread(const FileNode& );

    virtualvoid write( FileStorage& ) const;

    virtual Ptr<DescriptorMatcher> clone( bool emptyTrainData=false ) const=0;

    static Ptr<DescriptorMatcher> create( const string& descriptorMatcherType );

protected:

    vector<Mat> trainDescCollection;

...

};

3.1 DescriptorMatcher::create

创建特征匹配类，例如：cv::Ptr<cv::DescriptorMatcher>descriptor_matcher = cv::DescriptorMatcher::create("BruteForce");

可传入的参数如下：

BruteForce (ituses L2 )

BruteForce-L1

BruteForce-Hamming

BruteForce-Hamming(2)

FlannBased

3.2 DescriptorMatcher::match

特征匹配计算

4、drawMatches

显示匹配结果

计算结果：

0 0