Android遮罩并在轮廓周围按位应用

Question

设法做到这一点的是Python，但无法转换为Android。有人可以指出我的错误吗？ 目标：裁剪图像以仅显示屏幕。然后裁剪后，屏幕外的所有内容都会设置为黑色。

Python代码：

print('Please input file name with extension:')
image = cv2.imread(input(), cv2.IMREAD_COLOR) 

image2 = image.copy() #make copy for 2nd contour plot

scale_factor = 800 #input how big you want the image to be scaled down to here

original_image = scale_image(image.copy(), scale_factor)
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) 
gray = cv2.bilateralFilter(gray, 11, 17, 17) 
v = np.median(gray)
sigma = 0.33

lower = int(max(0, (1.0 - sigma) * v))
upper = int(min(255, (1.0 + sigma) * v))
edged = cv2.Canny(gray, lower, upper)

kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE,(9,9))
dilated = cv2.dilate(edged, kernel)
contours, hierarchy = cv2.findContours(dilated.copy(), cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)

print("Number of Contours found = " + str(len(contours)))

cnts = sorted(contours, key=cv2.contourArea,  reverse = True)[:10] 
screen_cnt = None

    for c in cnts:

        peri = cv2.arcLength(c, True)
        approx = cv2.approxPolyDP(c, 0.015 * peri, True)
        area = cv2.contourArea(cnts[1])

    if len(approx) == 4:
        screen_cnt = approx
        break

    rect = cv2.boundingRect(screen_cnt)
    x,y,w,h = rect
    croped = image[y:y+h, x:x+w].copy()

    screen_cnt = screen_cnt - screen_cnt.min(axis=0)

    mask = np.zeros(croped.shape[:2], np.uint8)
    cv2.drawContours(mask, [screen_cnt], -1, (255, 255, 255), -1, cv2.LINE_AA)

    dst = cv2.bitwise_and(croped, croped, mask=mask)

    cv2.drawContours(image2, [cnts[1]], -1, (0, 255, 0), 3) 
    contour_scaled3 = scale_image(image2, scale_factor) 
    cv2.imshow('Contours_of_screen', contour_scaled3)

Android代码：

        static void sortContoursByArea(List<MatOfPoint> contours) {

        for(int contourIdx=0; contourIdx < contours.size(); contourIdx++) {
            double areaC = Imgproc.contourArea(contours.get(contourIdx));
            if (areaC < 100000){
                contours.remove(contourIdx);
            }
        }

        Collections.sort(contours, (a, b) -> {

            double areaA = Imgproc.contourArea(a);
            double areaB = Imgproc.contourArea(b);

            // Change sign depending on whether your want sorted small to big
            // or big to small


            if (areaA < areaB) {
                return 1;
            } else if (areaA > areaB) {
                return -1;
            }
            return 0;
        });
    }

    public void edgeDetection(View v)
    {
        Mat srcMat = new Mat (imageBitmap.getHeight(), imageBitmap.getWidth(), CvType.CV_8UC3);

        Bitmap myBitmap32 = imageBitmap.copy(Bitmap.Config.ARGB_8888, true);

        Utils.bitmapToMat(myBitmap32, srcMat);

        Mat gray = new Mat(srcMat.size(), CvType.CV_8UC1);
        Imgproc.cvtColor(srcMat, gray, Imgproc.COLOR_RGB2GRAY);
        Mat edge = new Mat();
        Mat edge2 = new Mat();
        Mat edge3 = new Mat();
        List<MatOfPoint> contours = new ArrayList<>();

        Mat hierarchy = new Mat();
        Mat edge4 = new Mat();

        Imgproc.bilateralFilter(gray, edge, 11, 17, 17);
        Imgproc.Canny(edge, edge2, 80, 90);
        Mat element = Imgproc.getStructuringElement(Imgproc.MORPH_ELLIPSE, new Size(5,5));
        Imgproc.dilate(edge2, edge3, element);
        Imgproc.findContours(edge3, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE);

        sortContoursByArea(contours);

        for(int c = 0; c < contours.size(); c++) {
            MatOfPoint2f approxCurve = new MatOfPoint2f();
            MatOfPoint2f contour2f = new MatOfPoint2f(contours.get(c).toArray());
            double approxDistance = Imgproc.arcLength(contour2f, true) * 0.015;
            Imgproc.approxPolyDP(contour2f, approxCurve, approxDistance, true);

            if (approxCurve.toArray().length == 4) {
                MatOfPoint points = new MatOfPoint(approxCurve.toArray());
                // Get bounding rect of contour
                Rect rect = Imgproc.boundingRect(points);

                //Imgproc.rectangle(srcMat, new Point(rect.x, rect.y), new Point(rect.x + rect.width, rect.y + rect.height), new Scalar(0, 255, 0, 255), 3);
                edge4  = new Mat(srcMat, rect);
                break;
            }
        }

        // create Mat for mask
        Mat mask =  new Mat(new Size(edge4.cols(), edge4.rows() ), CvType.CV_8UC1);
        mask.setTo(new Scalar(0.0));

        // create Scalar for color of mask objects
        Scalar red = new Scalar(255, 0, 0);

        // draw contours border and fill them
        Imgproc.drawContours(mask, contours, -1, red, 10);
        for (MatOfPoint contour: contours) {
            Imgproc.fillPoly(mask, Collections.singletonList(contour), red);
        }

        // create mat foe masked image
        Mat masked = new Mat();

        // apply mask to srcMat and set result to masked
        edge4.copyTo(masked, mask);

        //Imgproc.drawContours(srcMat, contours, -1, new Scalar(0, 255, 0), -1);

        Bitmap resultBitmap = Bitmap.createBitmap(masked.cols(), masked.rows(),Bitmap.Config.ARGB_8888);
        Utils.matToBitmap(masked, resultBitmap);

        imageView.setImageBitmap(resultBitmap);
    }

图像在下面的链接中。 https://i.stack.imgur.com/63wdr.jpg