Example usage for org.opencv.core MatOfKeyPoint MatOfKeyPoint

Introduction

In this page you can find the example usage for org.opencv.core MatOfKeyPoint MatOfKeyPoint.

Prototype

public MatOfKeyPoint(KeyPoint... a) 

Source Link

Usage

From source file:eu.fpetersen.robobrain.behavior.followobject.OrbObjectDetector.java

License:Open Source License

public void process(Mat image) {
    Mat tempImage = new Mat();
    Imgproc.cvtColor(image, tempImage, Imgproc.COLOR_RGBA2RGB);
    MatOfKeyPoint keypoints = detectInImage(tempImage);
    Mat descriptors = extractDescriptors(keypoints, tempImage);
    MatOfDMatch matches = new MatOfDMatch();
    matcher.match(descriptors, originalDescriptors, matches);

    KeyPoint[] keypointArray = keypoints.toArray();
    KeyPoint[] originalKeypointArray = originalKeypoints.toArray();

    float min = 40.0f;
    float max = 1000.0f;
    for (DMatch match : matches.toList()) {
        if (match.distance < min) {
            min = match.distance;// w  ww .  j  ava  2 s  .c  om
        } else if (match.distance > max) {
            max = match.distance;
        }
    }

    float threshold = 1.5f * min;
    List<KeyPoint> matchedKeyPoints = new ArrayList<KeyPoint>();
    List<Point> matchedPoints = new ArrayList<Point>();
    List<Point> matchedOriginalPoints = new ArrayList<Point>();
    for (DMatch match : matches.toList()) {
        if (match.distance < threshold) {
            KeyPoint matchedKeypoint = keypointArray[match.queryIdx];
            matchedKeyPoints.add(matchedKeypoint);
            matchedPoints.add(matchedKeypoint.pt);

            KeyPoint matchedOriginalKeypoint = originalKeypointArray[match.trainIdx];
            matchedOriginalPoints.add(matchedOriginalKeypoint.pt);
        }
    }

    if (matchedKeyPoints.size() > 10) {

        Mat H = Calib3d.findHomography(
                new MatOfPoint2f(matchedOriginalPoints.toArray(new Point[matchedOriginalPoints.size()])),
                new MatOfPoint2f(matchedPoints.toArray(new Point[matchedPoints.size()])), Calib3d.RANSAC, 10);

        List<Point> originalCorners = new ArrayList<Point>();
        originalCorners.add(new Point(0, 0));
        originalCorners.add(new Point(originalImage.cols(), 0));
        originalCorners.add(new Point(originalImage.cols(), originalImage.rows()));
        originalCorners.add(new Point(0, originalImage.rows()));

        List<Point> corners = new ArrayList<Point>();
        for (int i = 0; i < 4; i++) {
            corners.add(new Point(0, 0));
        }
        Mat objectCorners = Converters.vector_Point2f_to_Mat(corners);

        Core.perspectiveTransform(Converters.vector_Point2f_to_Mat(originalCorners), objectCorners, H);
        corners.clear();
        Converters.Mat_to_vector_Point2f(objectCorners, corners);

        Core.line(tempImage, corners.get(0), corners.get(1), new Scalar(0, 255, 0), 4);
        Core.line(tempImage, corners.get(1), corners.get(2), new Scalar(0, 255, 0), 4);
        Core.line(tempImage, corners.get(2), corners.get(3), new Scalar(0, 255, 0), 4);
        Core.line(tempImage, corners.get(3), corners.get(0), new Scalar(0, 255, 0), 4);
    }

    Features2d.drawKeypoints(tempImage,
            new MatOfKeyPoint(matchedKeyPoints.toArray(new KeyPoint[matchedKeyPoints.size()])), tempImage);
    Imgproc.cvtColor(tempImage, image, Imgproc.COLOR_RGB2RGBA);

}

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