如何在java中使用opencv绘制线条

Question

问题是我无法使用单应矩阵制作线条，功能core.line不起作用或者我做错了，因为我在控制台上没有错误。 最后我有两张图片，但两者都是一样的，唯一不同的是黑点 几乎察觉不到。

图像第一匹配：https://www.dropbox.com/s/0hse2pk8a6tx6xj/firstMatching.png?dl=0

images finalMatching：https://www.dropbox.com/s/yust0wjnbkziq7a/final.png?dl=0

public class SearchObject {

    void run(String pathObject, String pathScene, String pathResult) {
        System.out.println("\n searching Object");
        // hier I define my images variables

        Mat myObject = Highgui.imread("C:/Users/Angel/Documents/mySpace/EncontrarObjeto/".concat(pathObject), 0); //0 = CV_LOAD_IMAGE_GRAYSCALE
        Mat myScene = Highgui.imread("C:/Users/Angel/Documents/mySpace/EncontrarObjeto/".concat(pathScene), 0);

        FeatureDetector detector = FeatureDetector.create(FeatureDetector.SIFT); // creamos el object para detectar por puntos claves, para este caso usaremos 4 = SURF 

        MatOfKeyPoint keyPointsObject = new MatOfKeyPoint(); 

        // I create the matrix kexPoints

        MatOfKeyPoint keyPointsScene  = new MatOfKeyPoint();

        detector.detect(myObject, keyPointsObject); 

        // here I use the function detect of detector object

        detector.detect(myScene, keyPointsScene);

        DescriptorExtractor extractor = DescriptorExtractor.create(DescriptorExtractor.SIFT); 

        // I create an object for extract the descriptors with SIFT

        Mat descriptorsObject = new Mat(); 
        Mat descriptorsScene = new Mat() ;

        extractor.compute(myObject, keyPointsObject, descriptorsObject);
        extractor.compute(myScene, keyPointsScene, descriptorsScene);

        // creating the object to matching with FLANNBASES 

        DescriptorMatcher matcher = DescriptorMatcher.create(1); 
        MatOfDMatch matches = new MatOfDMatch(); 

        matcher.match(descriptorsObject, descriptorsScene, matches); 
        List<DMatch> listaMatching = matches.toList(); 

        Double dist_max = 0.0; // definimos los maximos y minimos
        Double dist_min = 100.0;

        for(int i = 0; i < descriptorsObject.rows(); i++) {
            Double dist = (double) listaMatching.get(i).distance;
            if(dist < dist_min)
                dist_min = dist;
            if(dist > dist_max) 
                dist_max = dist;
        }

        System.out.println("distance Max: " + dist_max);
        System.out.println("distance Min : " + dist_min);    

        LinkedList<DMatch> good_matching = new LinkedList<DMatch>(); 
        MatOfDMatch GoodM = new MatOfDMatch();

        // select the good matching min <3*dist_min
        for(int i = 0; i < descriptorsObject.rows(); i++) {
            if(listaMatching.get(i).distance < 3*dist_min) {
                good_matching.addLast(listaMatching.get(i));
            }
        }

        GoodM.fromList(good_matching); 

        Mat img_matches = new Mat();

        Features2d.drawMatches(myObject, keyPointsObject, myScene, keyPointsScene, GoodM, img_matches, new Scalar(255,255,0), new Scalar(0,0,255), new MatOfByte(), 2);

        String firstMatching = "C:/Users/Angel/Documents/mySpace/EncontrarObjeto/PrimerMatching.png";

        System.out.println(String.format("writing the first matching %s", firstMatching));
        Highgui.imwrite(firstMatching, img_matches);

        LinkedList<Point> listObj = new LinkedList<Point>(); 
        LinkedList<Point> listScene = new LinkedList<Point>();

        List<KeyPoint> listObject_keyPoints = keyPointsObject.toList(); 
        List<KeyPoint> listScene_keyPoints = keyPointsScene.toList();

        for(int i = 0; i<good_matching.size(); i++) {
            listObj.addLast(listObject_keyPoints.get(good_matching.get(i).queryIdx).pt);
            listScene.addLast(listScene_keyPoints.get(good_matching.get(i).trainIdx).pt);
        }

        MatOfPoint2f object = new MatOfPoint2f();
        object.fromList(listObj);

        MatOfPoint2f scene = new MatOfPoint2f();
        scene.fromList(listScene);

        // searching the Homography matrix with ransac

        Mat H = Calib3d.findHomography(object, scene, Calib3d.RANSAC,0.5);
        //  Calib3d.correctMatches(H,object , escena, object, escena);
        Mat corners_Object = new Mat(4,1,CvType.CV_32FC2);
        Mat corners_Scene = new Mat(4,1,CvType.CV_32FC2);

        // defining the corners object

        corners_Object.put(0, 0, new double[] {0,0});
        corners_Object.put(1, 0, new double[] {myObject.cols(),0});
        corners_Object.put(2, 0, new double[] {myObject.cols(),myObject.rows()});
        corners_Object.put(3, 0, new double[] {0,myObject.rows()});

        Core.perspectiveTransform(corners_Object,corners_Scene, H);
        System.out.println("number of Cols:" + H.cols() + "number of Rows" + H.rows());
        System.out.println(H);
        Core.line(img_matches, new Point(corners_Scene.get(0,0)), new Point(corners_Scene.get(1,0)), new Scalar(0, 0, 0),4);
        Core.line(img_matches, new Point(corners_Scene.get(1,0)), new Point(corners_Scene.get(2,0)), new Scalar(0, 0, 0),4);
        Core.line(img_matches, new Point(corners_Scene.get(2,0)), new Point(corners_Scene.get(3,0)), new Scalar(0, 0, 0),4);
        Core.line(img_matches, new Point(corners_Scene.get(3,0)), new Point(corners_Scene.get(0,0)), new Scalar(0, 0, 0),4);

        // Path final result

        pathResult = "C:/Users/Angel/Documents/mySpace/EncontrarObjeto/resultado.png";


        System.out.println(String.format("Writing %s", pathResult));
        Highgui.imwrite(pathResult, img_matches);

        }
    }