特征的匹配大致可以分为3个步骤:
- 特征的提取
- 计算特征向量
- 特征匹配
对于3个步骤,在OpenCV2中都进行了封装。所有的特征提取方法都实现FeatureDetector接口,DescriptorExtractor接口则封装了对特征向量(特征描述符)的提取,而所有特征向量的匹配都继承了DescriptorMatcher接口。
surf
int main()
{
const string imgName1 = "x://image//01.jpg";
const string imgName2 = "x://image//02.jpg";
Mat img1 = imread(imgName1);
Mat img2 = imread(imgName2);
if (!img1.data || !img2.data)
return -1;
//step1: Detect the keypoints using SURF Detector
int minHessian = 400;
SurfFeatureDetector detector(minHessian);
vector<KeyPoint> keypoints1, keypoints2;
detector.detect(img1, keypoints1);
detector.detect(img2, keypoints2);
//step2: Calculate descriptors (feature vectors)
SurfDescriptorExtractor extractor;
Mat descriptors1, descriptors2;
extractor.compute(img1, keypoints1, descriptors1);
extractor.compute(img2, keypoints2, descriptors2);
//step3:Matching descriptor vectors with a brute force matcher
BFMatcher matcher(NORM_L2);
vector<DMatch> matches;
matcher.match(descriptors1, descriptors2,matches);
//Draw matches
Mat imgMatches;
drawMatches(img1, keypoints1, img2, keypoints2, matches, imgMatches);
namedWindow("Matches");
imshow("Matches", imgMatches);
waitKey();
return 0;
}