我使用了Sift/Surf和ORB，但有时我在drawMatch函数上遇到了问题。
这里的错误:
编码 :
drawMatchPoints(img1,keypoints_img1,img2,keypoints_img2,matches);
我试图像这样用img2和keypoints_img2来反转img 1，keypoints_img1:
drawMatchPoints(img2,keypoints_img2,img1,keypoints_img1,matches);
对应于我执行单应性检查的功能:
void drawMatchPoints(cv::Mat image1,std::vector<KeyPoint> keypoints_img1,
cv::Mat image2,std::vector<KeyPoint> keypoints_img2,std::vector<cv::DMatch> matches){
cv::Mat img_matches;
drawMatches( image1, keypoints_img1, image2, keypoints_img2,
matches, img_matches, Scalar::all(-1), Scalar::all(-1),
vector<char>(), DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS );
std::cout << "Number of good matching " << (int)matches.size() << "\n" << endl;
//-- Localize the object
std::vector<Point2f> obj;
std::vector<Point2f> scene;
for( int i = 0; i < matches.size(); i++ )
{
//-- Get the keypoints from the good matches
obj.push_back( keypoints_img1[ matches[i].queryIdx ].pt );
scene.push_back( keypoints_img2[matches[i].trainIdx ].pt );
}
Mat H = findHomography( obj, scene, CV_RANSAC );
std::cout << "Size of homography " << *H.size << std::endl ;
//-- Get the corners from the image_1 ( the object to be "detected" )
std::vector<Point2f> obj_corners(4);
obj_corners[0] = cvPoint(0,0); obj_corners[1] = cvPoint( image1.cols, 0 );
obj_corners[2] = cvPoint( image1.cols, image1.rows ); obj_corners[3] = cvPoint( 0, image1.rows );
std::vector<Point2f> scene_corners(4);
perspectiveTransform( obj_corners, scene_corners, H);
//-- Draw lines between the corners (the mapped object in the scene - image_2 )
line( img_matches, scene_corners[0] + Point2f( image1.cols, 0), scene_corners[1] + Point2f( image1.cols, 0), Scalar(0, 255, 0), 4 );
line( img_matches, scene_corners[1] + Point2f( image1.cols, 0), scene_corners[2] + Point2f( image1.cols, 0), Scalar( 0, 255, 0), 4 );
line( img_matches, scene_corners[2] + Point2f( image1.cols, 0), scene_corners[3] + Point2f( image1.cols, 0), Scalar( 0, 255, 0), 4 );
line( img_matches, scene_corners[3] + Point2f( image1.cols, 0), scene_corners[0] + Point2f( image1.cols, 0), Scalar( 0, 255, 0), 4 );
//-- Show detected matches
cv::imshow( "Good Matches & Object detection", img_matches );
cv::waitKey(5000);
}
但是我仍然有错误!
我已经注意到，当我的keypoints_img1 的大小比我的keypoints_img2的大小低时，就会发生错误:
因此，如果我反转两张图片的加载，就可以了，但是如果我的第一张图片比第二张图片具有更多的关键点，我现在无法提前进行...
我的代码(最重要的步骤)是为了创建功能:
init_Sift(400,5,0.04,25,1.6);
void init_Sift(int nf,int nOctaveL,double contrastThresh, double edgeThresh,double sigma){
this->nfeatureSift=nf;
this->nOctaveLayerSift=nOctaveL;
this->contrastThresholdSift=contrastThresh;
this->edgeThresholdSift=edgeThresh;
this->sigmaSift=sigma;}
cv::FeatureDetector* detector=new SiftFeatureDetector(nfeatureSift,nOctaveLayerSift,contrastThresholdSift,edgeThresholdSift,sigmaSift);
cv::DescriptorExtractor* extractor=new SiftDescriptorExtractor
extractor->compute( image, keypoints, descriptors );
配套部分:
std::cout << "Type of matcher : " << type_of_matcher << std::endl;
if (type_of_matcher=="FLANN" || type_of_matcher=="BF"){
std::vector<KeyPoint> keypoints_img1 = keyfeatures.compute_Keypoints(img1);
std::vector<KeyPoint> keypoints_img2 = keyfeatures.compute_Keypoints(img2);
cv::Mat descriptor_img1 = keyfeatures.compute_Descriptors(img1);
cv::Mat descriptor_img2 = keyfeatures.compute_Descriptors(img2);
std::cout << "Size keyPoint1 " << keypoints_img1.size() << "\n" << std::endl;
std::cout << "Size keyPoint2 " << keypoints_img2.size() << "\n" << std::endl;
//Flann with sift or surf
if (type_of_matcher=="FLANN"){
Debug::info("USING Matcher FLANN");
fLmatcher.match(descriptor_img1,descriptor_img2,matches);
double max_dist = 0; double min_dist = 100;
//-- Quick calculation of max and min distances between keypoints
for( int i = 0; i < descriptor_img1.rows; i++ ){
double dist = matches[i].distance;
if( dist < min_dist ) min_dist = dist;
if( dist > max_dist ) max_dist = dist;
}
std::vector< DMatch > good_matches;
for( int i = 0; i < descriptor_img1.rows; i++ )
{ if( matches[i].distance <= max(2*min_dist, 0.02) )
{ good_matches.push_back( matches[i]); }
}
std::cout << "Size of good match : " << (int)good_matches.size() << std::endl;
//-- Draw only "good" matches
if (!good_matches.empty()){
drawMatchPoints(img1,keypoints_img1,img2,keypoints_img2,good_matches);
}
else {
Debug::error("Flann Matcher : Pas de match");
cv::Mat img_matches;
drawMatches( img1, keypoints_img1, img2, keypoints_img2,
matches, img_matches, Scalar::all(-1), Scalar::all(-1),
vector<char>(), DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS );
cv::imshow( "No match", img_matches );
cv::waitKey(5000);
}
}
//BruteForce with sift or surf
else if (type_of_matcher=="BF"){
Debug::info("USING Matcher Brute Force");
bFmatcher.match(descriptor_img1,descriptor_img2,matches);
if (!matches.empty()){
std::nth_element(matches.begin(),//Initial position
matches.begin()+24, //Position of the sorted element
matches.end());//End position
matches.erase(matches.begin()+25,matches.end());
drawMatchPoints(img1,keypoints_img1,img2,keypoints_img2,matches);
//drawMatchPoints(img2,keypoints_img2,img1,keypoints_img1,matches);
}
else {
Debug::error("Brute Force matcher : Pas de match");
cv::Mat img_matches;
drawMatches( img1, keypoints_img1, img2, keypoints_img2,
matches, img_matches, Scalar::all(-1), Scalar::all(-1),
vector<char>(), DrawMatchesFlags::NOT_DRAW_SINGLE_POINTS );
cv::imshow( "No match", img_matches );
cv::waitKey(5000);
}
}
您有什么建议或建议吗？
编辑:我解决了我的问题。
我有一个C++问题，因为我有两个类。一个关于匹配，另一个关于找到keyFeature。我在.h std::vector上写过，对描述符也一样。
class keyFeatures{
public:
...
std::vector<keyPoint> keypoints;
...
我删除了此属性，并做了一个接受参数std::vector关键点的函数
cv::Mat descriptor_img1 = keyfeatures.compute_Descriptors(img1,keypoints_img1);
代替
cv::Mat descriptor_img1 = keyfeatures.compute_Descriptors(img1);
我认为进行匹配时存在冲突...
但是我不知道为什么我不必在.h上编写它并在函数上执行局部参数。
谢谢 !
最佳答案
对于像我这样搜索但找不到解决方案的人。
这意味着断言由于i2小于0或i2小于keypoints2大小而失败。但是，i2是什么？
从rbaleksandar在评论中提供的链接
trainIdx是keypoints2中的索引。检查i2
对我来说，发生这种情况是因为我在调用drawMatches之前但在计算了描述符之后即即调用了DescriptorExtractor＃compute时丢弃了一些关键点。这意味着在我更改那些关键点时，drawMatches通过描述符引用了旧的关键点。最终结果是某些关键点具有较大的idx，但关键点大小较小，因此会出现错误。
关于c++ - OpenCV筛选/冲浪/球体: drawMatch function is not working well，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/24552590/