使用 openCV 在 android 中进行 Hough 线检测

Question

我的 mRgba 对象的尺寸为 0X0，因此它 return 图片上没有任何线条在 all.I 猜测它是空的。代码中的问题是什么？有没有办法显示线条黑色背景？

这是代码

    mat = new Mat();
    edges = new Mat();
    Size kernel = new Size(5, 5);
    Mat gauss = new Mat();
    Mat mRgba = new Mat(612,816, CvType.CV_8UC1);
    Mat lines = new Mat(612,816, CvType.CV_8UC1);
    binary_image = new Mat();
    Utils.bitmapToMat(bitmap, mat);
    Imgproc.GaussianBlur(mat, gauss, kernel, 10000, 10000);
    Imgproc.Canny(gauss, edges, 50, 90);
    Imgproc.threshold(edges, binary_image, 0, 255, Imgproc.THRESH_BINARY_INV);

    int threshold = 50;
    int minLineSize = 20;
    int lineGap = 20;

    Imgproc.HoughLinesP(binary_image, lines, 1, Math.PI / 180,threshold,minLineSize,lineGap);



    for (int x = 0; x < lines.cols(); x++) {
        double[] vec = lines.get(0, x);
        double x1 = vec[0],
                y1 = vec[1],
                x2 = vec[2],
                y2 = vec[3];
        Point start = new Point(x1, y1);
        Point end = new Point(x2, y2);

        Core.line(mRgba, start, end, new Scalar(255, 0, 0), 3);

    }

    Bitmap bmp = Bitmap.createBitmap(mRgba.cols(), mRgba.rows(), Bitmap.Config.ARGB_8888);

    Utils.matToBitmap(mRgba, bmp);
        bitmap=bmp;

编辑：问题已通过删除高斯模糊和阈值方法得到解决

    mat = new Mat();
    edges = new Mat();      
    Mat mRgba = new Mat(612,816, CvType.CV_8UC1);
    Mat lines = new Mat();

    Utils.bitmapToMat(bitmap, mat);

    Imgproc.Canny(mat, edges, 50, 90);


    int threshold = 50;
    int minLineSize = 20;
    int lineGap = 20;

    Imgproc.HoughLinesP(edges, lines, 1, Math.PI / 180,threshold,minLineSize,lineGap);



    for (int x = 0; x < lines.cols(); x++) {
        double[] vec = lines.get(0, x);
        double x1 = vec[0],
                y1 = vec[1],
                x2 = vec[2],
                y2 = vec[3];
        Point start = new Point(x1, y1);
        Point end = new Point(x2, y2);

        Core.line(mRgba, start, end, new Scalar(255, 0, 0), 3);

    }

    Bitmap bmp = Bitmap.createBitmap(mRgba.cols(), mRgba.rows(), Bitmap.Config.ARGB_8888);

    Utils.matToBitmap(mRgba, bmp);
        bitmap=bmp;

Answer 1

您在创建 mRgba 时没有指定尺寸，它应该与您尝试查找线条的图像具有相同的尺寸。
您应该检查 lines 对象，看看您是否能够找到线条或不是。查mRgba.
这似乎不是全部代码，这里没有加载图片。您最好也共享整个代码和示例图像。

使用 openCV 在 android 中进行 Hough 线检测

Hough line detection in android using openCV

android

opencv

image-processing

hough-transform