Example usage for org.opencv.imgproc Imgproc ellipse

Introduction

In this page you can find the example usage for org.opencv.imgproc Imgproc ellipse.

Prototype

public static void ellipse(Mat img, RotatedRect box, Scalar color, int thickness, int lineType) 

Source Link

Usage

From source file:dfmDrone.examples.fitEllipseExample.java

private static Mat findAndDrawEllipse(Mat sourceImg) {
    Mat grayScaleImg = new Mat();
    Mat hsvImg = new Mat();
    Imgproc.cvtColor(sourceImg, hsvImg, Imgproc.COLOR_BGR2HSV);
    Mat lower_hue_range = new Mat();
    Mat upper_hue_range = new Mat();
    Core.inRange(hsvImg, new Scalar(0, 100, 45), new Scalar(15, 255, 255), lower_hue_range);
    Core.inRange(hsvImg, new Scalar(160, 100, 45), new Scalar(180, 255, 255), upper_hue_range);
    Mat red_hue_image = new Mat();
    Core.addWeighted(lower_hue_range, 1.0, upper_hue_range, 1.0, 0, red_hue_image);
    Mat dilateElement = Imgproc.getStructuringElement(Imgproc.MORPH_RECT, new Size(24, 24));
    Mat erodeElement = Imgproc.getStructuringElement(Imgproc.MORPH_RECT, new Size(10, 10));

    Imgproc.blur(red_hue_image, red_hue_image, new Size(11, 11));
    // init/* w w  w  . j  av  a2 s .co m*/
    List<MatOfPoint> contours = new ArrayList<>();
    Mat hierarchy = new Mat();

    // find contours
    Imgproc.findContours(red_hue_image, contours, hierarchy, Imgproc.RETR_CCOMP, Imgproc.CHAIN_APPROX_SIMPLE);
    System.out.println("After findcontours");
    // if any contour exist...
    if (hierarchy.size().height > 0 && hierarchy.size().width > 0) {
        // for each contour, display it in blue
        for (int idx = 0; idx >= 0; idx = (int) hierarchy.get(0, idx)[0]) {
            System.out.println(idx);
            //   Imgproc.drawContours(frame, contours, idx, new Scalar(250, 0, 0), 3);

        }
    }
    MatOfPoint2f approxCurve = new MatOfPoint2f();

    //For each contour found
    MatOfPoint2f contour2f = null;
    RotatedRect rotatedrect = null;
    for (MatOfPoint contour : contours) {
        //Convert contours(i) from MatOfPoint to MatOfPoint2f
        if (contour2f == null)
            contour2f = new MatOfPoint2f(contour.toArray());
        if (contour.size().area() > contour2f.size().area()) {
            contour2f = new MatOfPoint2f(contour.toArray());
        }
    }
    try {
        Imgproc.fitEllipse(contour2f);
        rotatedrect = Imgproc.fitEllipse(contour2f);

        double approxDistance = Imgproc.arcLength(contour2f, true) * 0.02;
        Imgproc.approxPolyDP(contour2f, approxCurve, approxDistance, true);

        //Convert back to MatOfPoint
        MatOfPoint points = new MatOfPoint(approxCurve.toArray());

        // Get bounding rect of contour
        Rect rect = Imgproc.boundingRect(points);

        // draw enclosing rectangle (all same color, but you could use variable i to make them unique)
        Imgproc.rectangle(sourceImg, rect.tl(), rect.br(), new Scalar(255, 0, 0), 1, 8, 0);
        Imgproc.ellipse(sourceImg, rotatedrect, new Scalar(255, 192, 203), 4, 8);
    } catch (CvException e) {
        e.printStackTrace();
        System.out.println("Ingen ellipse fundet");
    }
    return sourceImg;
}

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