Converting Mat to Keypoint?

Question

I\'m writing both descriptors (SurfDescriptorExtractor output) and keypoints (SurfFeatureDetector output) to an XML file. Before writing keypoints (std::vector) conversion to Ma

Answer 1

Just found this by looking at OpenCV source (under /modules/java/generator/src/cpp/converters.cpp, around line 185):

void Mat_to_vector_KeyPoint(Mat& mat, vector& v_kp)
{
    v_kp.clear();
    CHECK_MAT(mat.type()==CV_32FC(7) && mat.cols==1);
    for(int i=0; i v = mat.at< Vec >(i,0);
        KeyPoint kp(v[0], v[1], v[2], v[3], v[4], (int)v[5], (int)v[6]);
        v_kp.push_back(kp);
    }
    return;
}

And I'm using it as:

vector mat_to_keypoints(Mat* mat) {

    vector  c_keypoints;

    for ( int i = 0; i < mat->rows; i++) {
        Vec v = mat.at< Vec >(i,0);

        KeyPoint kp(v[0], v[1], v[2], v[3], v[4], (int)v[5], (int)v[6]);

        c_keypoints.push_back(kp);

    };

    return c_keypoints;

};