opencv - JavaCV 为 SIFT 关键点计算 ORB 描述符

Question

我在为 SIFT 检测器找到的关键点计算 ORB 描述符时遇到了很大的问题。如果我尝试运行一个简单的示例程序，整个系统就会死机，而且我不知道为什么。示例代码如下:

import static com.googlecode.javacv.cpp.opencv_highgui.cvLoadImageM;

import com.googlecode.javacv.cpp.opencv_core.CvMat;
import com.googlecode.javacv.cpp.opencv_features2d.DescriptorExtractor;
import com.googlecode.javacv.cpp.opencv_features2d.FeatureDetector;
import com.googlecode.javacv.cpp.opencv_features2d.KeyPoint;
import com.googlecode.javacv.cpp.opencv_features2d.ORB;
import com.googlecode.javacv.cpp.opencv_nonfree.SIFT;

public class DescriptorTest {

    public static void main(String[] args) {
        SIFT sift = new SIFT(0, 3, 0.04, 10, 1.6);
        FeatureDetector detector = sift.getFeatureDetector();
        ORB orb_descriptor = new ORB(500, 1.2f, 8, 31, 0, 2, 0, 31);
        DescriptorExtractor descriptor = orb_descriptor.getDescriptorExtractor();        
        CvMat image = cvLoadImageM("res/dvd_009_ref.jpg");
        KeyPoint keypoints = new KeyPoint();
        CvMat descriptors = new CvMat(null);
        detector.detect(image, keypoints, null);
        System.out.println("Keypoints found: "+ keypoints.capacity());
        descriptor.compute(image, keypoints, descriptors);
        System.out.println("Descriptors calculated: "+descriptors.rows());
    }
}

有人知道问题出在哪里吗？会很棒:)

Answer 1

好吧，如果我将关键点的 Octave 设置为 0，它似乎可以工作。我还不知道这是否是个好主意，但我倾向于拒绝。因为对于某些描述符来说，在其中发现特征的尺度空间 Octave 音阶的信息是至关重要的。

for(int i = 0; i < keypoints.capacity(); i++) {
    KeyPoint kp = keypoints.position(i);
    kp.octave(0);
}
keypoints.position(0);