如何合并斑点/轮廓

Question

我使用findContours 进行斑点检测。现在，我会将紧密且相似的 blob 合并在一起。

以下是一些示例图片：

普通的 Opencv 可以吗？

Answer 1

您提供给我们的输入图像非常易于使用：

第一步是将黄色斑点与其他所有东西分开，一个简单的颜色分割技术可以完成这项任务。您可以查看Segmentation & Object Detection by color 或Tracking colored objects in OpenCV 以了解如何操作。

然后，是时候合并 blob。一种特别有用的技术是bounding box，用于将所有 blob 放在一个矩形内。请注意，在下图中，斑点周围有一个绿色矩形：

之后，您需要做的就是用您选择的颜色填充矩形，从而连接所有的斑点。我把这个留给你作为作业。

这是我能想到的最快、最简单的方法。下面的代码演示了如何实现我刚才描述的：

#include <cv.h>
#include <highgui.h>

#include <iostream>
#include <vector>

int main(int argc, char* argv[])
{
    cv::Mat img = cv::imread(argv[1]);
    if (!img.data)
    {
        std::cout "!!! Failed to open file: " << argv[1] << std::endl;
        return 0;
    }

    // Convert RGB Mat into HSV color space
    cv::Mat hsv;
    cv::cvtColor(img, hsv, CV_BGR2HSV);

    // Split HSV Mat into HSV components
    std::vector<cv::Mat> v;
    cv::split(hsv,v);

    // Erase pixels with low saturation
    int min_sat = 70;
    cv::threshold(v[1], v[1], min_sat, 255, cv::THRESH_BINARY);

    /* Work with the saturated image from now on */

// Erode could provide some enhancement, but I'm not sure.
//  cv::Mat element = cv::getStructuringElement(cv::MORPH_RECT, cv::Size(3, 3));
//  cv::erode(v[1], v[1], element);

    // Store the set of points in the image before assembling the bounding box
    std::vector<cv::Point> points;
    cv::Mat_<uchar>::iterator it = v[1].begin<uchar>();
    cv::Mat_<uchar>::iterator end = v[1].end<uchar>();
    for (; it != end; ++it)
    {
        if (*it) points.push_back(it.pos());
    }

    // Compute minimal bounding box
    cv::RotatedRect box = cv::minAreaRect(cv::Mat(points));

    // Display bounding box on the original image
    cv::Point2f vertices[4];
    box.points(vertices);
    for (int i = 0; i < 4; ++i)
    {
            cv::line(img, vertices[i], vertices[(i + 1) % 4], cv::Scalar(0, 255, 0), 1, CV_AA);
    }

    cv::imshow("box", img);
    //cv::imwrite(argv[2], img);

    cvWaitKey(0);

    return 0;
}

Answer 2

我想我做到了，感谢您的程序详细信息，我找到了这个解决方案：（欢迎使用 cmets）

vector<vector<Point> > contours;
    vector<vector<Point> > tmp_contours;
    findContours(detectedImg, tmp_contours, CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE);

    vector<vector<Point> >::iterator it1;
    it1 = tmp_contours.begin();

    Mat test;
    test = Mat(FImage.size(), CV_32FC3);

    while (it1 != tmp_contours.end()) {
        vector<Point> approx1;
        approxPolyDP(Mat(*it1), approx1, 3, true);
        Rect box1 = boundingRect(approx1);
        float area1 = contourArea(approx1);



        if ((area1 > 50) && (area1 < 13000) && (box1.width < 100) && (box1.height < 120)) {

            vector<vector<Point> >::iterator it2;
            it2 = tmp_contours.begin();

            while (it2 != tmp_contours.end()) {
                vector<Point> approx2;
                approxPolyDP(Mat(*it2), approx2, 3, true);

                Moments m1 = moments(Mat(approx1), false);
                Moments m2 = moments(Mat(approx2), false);
                float x1 = m1.m10 / m1.m00;
                float y1 = m1.m01 / m1.m00;
                float x2 = m2.m10 / m2.m00;
                float y2 = m2.m01 / m2.m00;

                vector<Point> dist;
                dist.push_back(Point(x1, y1));
                dist.push_back(Point(x2, y2));
                float d = arcLength(dist, false);

                Rect box2 = boundingRect(approx2);
                if (box1 != box2) {

                    if (d < 25) {
                        //Method to merge the vectors
                        approx1 = mergePoints(approx1, approx2);
                    }

                }
                ++it2;

            }
            Rect b = boundingRect(approx1);
            rectangle(test, b, CV_RGB(125, 255, 0), 2);
            contours.push_back(approx1);
        }
        ++it1;
    }