opencv - 从二进制图像中删除 blob

Question

我有一个包含少量斑点的二进制图像。

我想删除小于某个区域的 blob。

任何人都可以建议我一种方法吗？

我正在使用 Open-CV。我做了膨胀和腐蚀来得到那些斑点。所以我需要一些不同的东西来去除小于某个区域的铰孔。

Answer 1

你可以这样做：

// your input binary image
// assuming that blob pixels have positive values, zero otherwise
Mat binary_image; 

// threashold specifying minimum area of a blob
double threshold = 100;

vector<vector<Point>> contours;
vector<Vec4i> hierarchy;
vector<int> small_blobs;
double contour_area;
Mat temp_image;

// find all contours in the binary image
binary_image.copyTo(temp_image);
findContours(temp_image, contours, hierarchy, CV_RETR_CCOMP,
                                                  CV_CHAIN_APPROX_SIMPLE);

// Find indices of contours whose area is less than `threshold` 
if ( !contours_all.empty()) {
    for (size_t i=0; i<contours.size(); ++i) {
        contour_area = contourArea(contours_all[i]) ;
        if ( contour_area < threshold)
            small_blobs.push_back(i);
    }
}

// fill-in all small contours with zeros
for (size_t i=0; i < small_blobs.size(); ++i) {
    drawContours(binary_image, contours, small_blobs[i], cv::Scalar(0), 
                                                 CV_FILLED, 8);
}

Answer 2

            //src_gray is your image that we threshold
            threshold(src_gray, threshold_output, NULL, 255, THRESH_OTSU);
            /// Find contours
            findContours(threshold_output, contours, hierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0));
            /// Approximate contours
            vector<Rect> boundRect(contours.size());
            for (unsigned int i = 0; i < contours.size(); i++)
            {   //identify bounding box
                boundRect[i] = boundingRect(contours[i]);
            }
            for (unsigned int i = 0; i < contours.size(); i++)
            {

                if ((boundRect[i].area() < //enter your area here))
                {
                    src_gray(boundRect[i])=//set it to whatever value you want;
                }
            }

那么试试这个...