ORB特徴点のマッチング

こんにちわ。Uedaです。

OpenCVを使って、ORB特徴点で2枚の画像からどこが同じ特徴のところかを調べてみました。

    UIImage *image1 = [UIImage imageNamed:@"IMG_0091.jpg"];
    UIImage *image2 = [UIImage imageNamed:@"IMG_0092.jpg"];
    
    Mat imageMat1 = [self cvMatFromUIImage:image1];
    Mat imageMat2 = [self cvMatFromUIImage:image2];
    
    Mat grayImage1, grayImage2;
    cvtColor(imageMat1, grayImage1, CV_BGR2GRAY);
    cvtColor(imageMat2, grayImage2, CV_BGR2GRAY);
    
    OrbFeatureDetector detector(500);
    OrbDescriptorExtractor extractor;
    
    std::vector keypoints1, keypoints2;
    detector.detect(grayImage1, keypoints1);
    detector.detect(grayImage2, keypoints2);
    
    Mat descriptor1, descriptor2;
    extractor.compute(grayImage1, keypoints1, descriptor1);
    extractor.compute(grayImage2, keypoints2, descriptor2);
    
    vector matches;
    BFMatcher matcher(cv::NORM_HAMMING, true);
    matcher.match(descriptor1, descriptor2, matches);
    
    for (int i = 0; i < matches.size(); i++)
    {
        NSLog(@"%f", matches[i].distance);
        if (matches[i].distance < 50.0)
        {
            KeyPoint p1 = keypoints1.at(matches[i].queryIdx);
            cv::circle(imageMat1, cv::Point(p1.pt.x, p1.pt.y), 20, Scalar(255, 255, 0), -1);
            
            KeyPoint p2 = keypoints2.at(matches[i].trainIdx);
            cv::circle(imageMat2, cv::Point(p2.pt.x, p2.pt.y), 20, Scalar(255, 255, 0), -1);
        }
    }
    
    [self.imageView1 setImage:[self UIImageFromCVMat:imageMat1]];
    [self.imageView2 setImage:[self UIImageFromCVMat:imageMat2]];

結果


うーん...

以上です。