Opencv Error: Assertion failed (ssize.area() > 0)

Asked

Viewed 208 times

1

I am having the following error with the Opencv library in Java:

Opencv Error: Assertion failed (ssize.area() > 0) in cv::resize, file ..... opencv modules imgproc src imgwarp.cpp, line 1834

Code:

    Mat img = new Mat();
    // capturar primeiro frame do video 
    VideoCapture cap = new VideoCapture(Options.videoAtual);
    cap.read(img);

    // passar a imagem para tons de cinza
    Mat grayImg = new Mat();
    Imgproc.cvtColor(img, grayImg, Imgproc.COLOR_BGR2GRAY);

    // aplicar filtro da media para reduzir os ruidos
    Imgproc.medianBlur(grayImg, grayImg, 7);
    Highgui.imwrite("tmp/img1.jpg", grayImg);

    // aplicar transformada circular de hough
    Mat circles = new Mat();
    Imgproc.HoughCircles(grayImg, circles, Imgproc.CV_HOUGH_GRADIENT,1,20, 
            180,18,minRaio,maxRaio);

    for (int x = 0; x < circles.cols(); x++) {
        double vCircle[] = circles.get(0, x);

        Point center = new Point(Math.round(vCircle[0]), Math.round(vCircle[1]));
        int radius = (int) Math.round(vCircle[2]);

        Centro = center;
        Raio = radius;

        // draw the circle outline
        Core.circle(img, center, radius, new Scalar(0, 0, 255), 3, 8, 0);
    }

    Highgui.imwrite("houghcircles.jpg", img);
java opencv

  • Have you figured out which of the lines in your code is responsible for triggering this error? Use the Debugger.

1 answer

1

This error indicates that the source image is empty (invalid image).

Try to follow the following steps:

  1. Make sure the opencv libraries are properly linked;
  2. Test with an image loaded directly from the disk using imread().
  3. If step 2 worked, add a sleep() or a waitkey() after the cap.read(img) to await a response from the video.

If you have any questions, ask in the comments.

Browser other questions tagged java opencv

You are not signed in. Login or sign up in order to post.