找到所有同心圆并使用 OpenCV C++ 填充它们

Question

I have an image of concentric circles. Now I want to find some of them and fill the area between then with white color. I have done canny edge detection then erosion and area filter and got the below output. I later on tried contouring but I am getting extra concentric circles. Original image:

Region to be extracted:

This is what I have tried:

        Mat cannyimg;
        Canny(histimg, cannyimg,35,65);
    
        Mat dilateimg;
        Mat kernel1 = getStructuringElement(MORPH_ELLIPSE, Size(2,2));
        dilate(cannyimg, dilateimg, kernel1, Point(-1, -1), 2);
    
        Mat imga = minareafilter(dilateimg, 500);
        
    
    
        vector<vector<Point> > contours;
        findContours(imga, contours, RETR_TREE, CHAIN_APPROX_SIMPLE);
        vector<vector<Point> > contours_poly(contours.size());
        vector<Rect> boundRect(contours.size());
        vector<Point2f>centers(contours.size());
        vector<float>radius(contours.size());
        for (size_t i = 0; i < contours.size(); i++)
        {
            approxPolyDP(contours[i], contours_poly[i], 3, true);
            boundRect[i] = boundingRect(contours_poly[i]);
            minEnclosingCircle(contours_poly[i], centers[i], radius[i]);
            
        }
        Mat drawing = Mat::zeros(imga.size(), CV_8UC3);
        for (size_t i = 0; i < contours.size(); i++)
        {
            Scalar color = Scalar(rng.uniform(0, 256), rng.uniform(0, 256), rng.uniform(0, 256));
            if (radius[i] > 50 && radius[i] < 100) {
                //drawContours(drawing, contours_poly, (int)i, color);
                //rectangle(drawing, boundRect[i].tl(), boundRect[i].br(), color, 2);
                circle(drawing, centers[i], (int)radius[i], color, 2);
            }
        }

My canny image is

After area filter the image is:

after contouring the image is:

Answer 1

The problem seems mostly based on detecting the contours efficiently. I tried the code which I have coded before to find the circles with an own method. You may check and try it here .

When I tried, I got the contours very clearly:

Then I tried to find the circles with same code and it found the circles and here is the result(I just rectangled the circles you need):

After detecting the circles, you need to design an algorithm for the desired circles. You may number their radius and choose the order accordingly. Here is your target output which I colorized with fillConvexPolly . (I manually chose the circles here):

Edit:

cv::fillConvexPoly(input, contour[outerId],cv::Scalar(0,0,255));
cv::fillConvexPoly(input,contour[innerrId],cv::Scalar(0,255,255));