Java OpenCV：从图像数据设置MatOfKeyPoints

我在OpenCV中创建了一个FeatureDetector。现在我不想使用所有的关键点。所以我决定用面具。现在我有两个问题：
一,。我是使用MatOfKeyPoint还是使用Mat类，两者都在OpenCV核心中。
二,。如何根据包含二进制信息的图片中的数据设置掩码

这是我到目前为止所拥有的

@SuppressWarnings("static-access")
public static void run() {
    System.loadLibrary(Core.NATIVE_LIBRARY_NAME);

    String sourcePath = "pic.png";
    Features2d features2d = new Features2d();
    Mat srcImgMat = Highgui.imread(sourcePath);
    if (srcImgMat == null) {
        System.out.println("Failed to load image at " + sourcePath);
        return;
    }

    System.out.println("Loaded image at " + sourcePath);

    MatOfKeyPoint matOfKeyPoints = new MatOfKeyPoint();
    FeatureDetector blobDetector = FeatureDetector.create(FeatureDetector.DENSE);  

    blobDetector.detect(srcImgMat, matOfKeyPoints);
    //============================================================================================================
    MatOfKeyPoint matOfKeyPointsSecond = new MatOfKeyPoint();
    Mat mask = new Mat();

    //picture with binary data
    File file = new File("binary.jpg");
    BufferedImage image = ImageIO.read(file);