Java 仅在帧的一部分上检测轮廓

是否有可能在传入帧的一部分上检测轮廓

    Imgproc.findContours(threshold_output, contourList, mHierarchy,
            Imgproc.RETR_EXTERNAL, Imgproc.CHAIN_APPROX_SIMPLE);

    Rect rect = new Rect(new Point(0,0), new Point(x,y));
    Mat subMat = incomingFrame.submat(rect);
    // MAKE ONLY CONTOUR OUTSIDE RECT DETECTABLE
    subMat.copyTo(incomingFrame.submat(rect));

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假设您已经知道如何在图像中查找轮廓，或者如何准备垫子查找轮廓。您只需在Mat中指定感兴趣的ROI区域

应用此方法后，我得到以下结果：

输入

输出

正如您所见，它无法识别整个矩形，而只能识别ROI内的部分矩形。

垫子的ROI也是垫子。你可以取出rect描述的ROI，然后用垫子做任何事情。

Mat frame = Highgui.imread("image/test.jpg");
// this is not a copy of frame, drawings on frameROI will also appear on frame
// rect describes ROI, starting at x,y = 50 and width, height = 100 
Mat frameROI = new Mat(frame, new Rect(50, 50, 100, 100));

// find contours in (processed to improve contour finding) frameROI
Imgproc.findContours(frameROIprepared, contours, hierarchy, Imgproc.RETR_EXTERNAL, Imgproc.CHAIN_APPROX_SIMPLE);

// go through all the contours in my contour list and draw them
for (int i = 0; i < contours.size(); i++)
    Imgproc.drawContours(frameROI, contours, i, new Scalar(0, 255, 0));