为什么ORB找不到关键点

如何解决为什么ORB找不到关键点

我正在尝试合并两个图像，但是ORB找不到关键点。这只是使用同一图像的一个示例，暗点是由采集引起的，不是很好的参考点，因此我应用了遮罩来避免它们。问题是，如果遮盖了黑点，则不会检测到任何关键点，我想知道是什么问题。

    final ORB orb = ORB.create(100);
    MatOfKeyPoint keypoints = new MatOfKeyPoint();
    Mat descriptors = new Mat();
    final Mat ones = Mat.ones(426,195,CV_8U);
    orb.detectAndCompute(draw,zeroMask,keypoints,descriptors);
    MatOfKeyPoint keypoints2 = new MatOfKeyPoint();
    Mat descriptors2 = new Mat();
    final List<KeyPoint> keyPoints = keypoints.toList();
    orb.detectAndCompute(draw,keypoints2,descriptors2);

    final DescriptorMatcher matcher = DescriptorMatcher.create(DescriptorMatcher.BRUTEFORCE_HAMMING);
    final MatOfDMatch matches = new MatOfDmatch();
    matcher.match(descriptors,descriptors2,matches);
    final Mat links = new Mat();
    final MatOfByte ones1 = new MatOfByte();
    org.opencv.features2d.Features2d.drawMatches(draw,draw,matches,links,new Scalar(0),ones1);