计算连通区域的像素点个数，找目标圆点

任务
圈出小圆点，不能圈不规则白点

参考知识
http://blog.csdn.net/qq_16540387/article/details/78844965
http://blog.csdn.net/qq_16540387/article/details/78843936
源码

//------------------------------------------------------------------------------------------------#include "opencv2/imgproc/imgproc.hpp"#include "opencv2/highgui/highgui.hpp"#include <iostream>using namespace cv;using namespace std;#define WINDOW_NAME "【程序窗口】"        //为窗口标题定义的宏 double area;//轮廓面积int g_nThresholdValue = 131;//二值化阈值int g_nThresholdType = 3;double minarea = 378;//目标轮廓最小像素点个数double maxarea = 478;//目标轮廓最大像素点个数Moments mom; // 轮廓矩  Mat image, gray, edge, dst, g_srcImage1, dst1,g_srcImage,g_grayImage,g_dstImage;vector<vector<Point> > contours;   //轮廓数组  vector<Point2d>  centers;    //轮廓质心坐标   vector<vector<Point> >::iterator itr;  //轮廓迭代器  vector<Point2d>::iterator  itrc;    //质心坐标迭代器  vector<vector<Point> > con;    //当前轮廓  Point2d center;//质心坐标void on_Threshold(int, void*);//回调函数int main(){    //【1】读入源图片    g_srcImage = imread("pos71_run7_img190.jpg");    //resize(g_srcImage, g_srcImage1, Size(g_srcImage.cols / 4, g_srcImage.rows / 4), 0, 0, INTER_LINEAR);    //imshow("原始图", g_srcImage1);    cvtColor(g_srcImage, g_grayImage, COLOR_RGB2GRAY);//灰度转换    namedWindow(WINDOW_NAME, WINDOW_AUTOSIZE);    createTrackbar("模式",        WINDOW_NAME, &g_nThresholdType,//二值化模式        4, on_Threshold);    createTrackbar("参数值",        WINDOW_NAME, &g_nThresholdValue,//二值化阈值         255, on_Threshold);    on_Threshold(0, 0);//滑动条回调函数    while (1)    {        int key;        key = waitKey(20);        if ((char)key == 27){ break; }    }}void on_Threshold(int, void*){    //调用阈值函数    threshold(g_grayImage, g_dstImage, g_nThresholdValue, 255, CV_THRESH_BINARY);    //resize(g_dstImage, g_srcImage1, Size(g_dstImage.cols / 4, g_dstImage.rows / 4), 0, 0, INTER_LINEAR);    //imshow("threshold", g_srcImage1);    Mat element2 = getStructuringElement(MORPH_RECT, Size(10, 10));//膨胀模板    Mat erode1, erode2;    dilate(g_dstImage, erode1, element2);//膨胀    dilate(erode1, erode2, element2);    //resize(erode2, g_srcImage1, Size(erode2.cols / 4, erode2.rows / 4), 0, 0, INTER_LINEAR);    //imshow("dilate", g_srcImage1);    findContours(erode2, contours,        CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE);//找出轮廓    itr = contours.begin();     //使用迭代器去除非目标轮廓      while (itr != contours.end())    {        area = contourArea(*itr);//计算面积        if ((area<minarea) | (area>maxarea))        {            itr = contours.erase(itr);  //删除        }        else        {            itr++;        }    }    dst = Mat::zeros(erode2.rows, erode2.cols, CV_8UC3);//保存中间结果    itr = contours.begin();    while (itr != contours.end())    {        area = contourArea(*itr);        con.push_back(*itr);        //cout << "\nb " << area;        drawContours(dst, con, -1, Scalar(255, 0, 0), 2);   //目标区域蓝色绘制          mom = moments(*itr);   //计算质心        center.x = (int)(mom.m10 / mom.m00);        center.y = (int)(mom.m01 / mom.m00);        char tam[10000];        char sam[10000];        sprintf(tam, "(%0.0f)", area);        sprintf(sam, "(%0.0f,%0.0f)", center.x, center.y);        putText(dst, tam, Point(center.x, center.y), FONT_HERSHEY_SIMPLEX, 2, Scalar(255, 0, 0), 5);//标出面积        putText(dst, sam, Point(center.x, center.y + 80), FONT_HERSHEY_SIMPLEX, 2, Scalar(0, 255, 0), 5);//标出质心        //imwrite("20003.jpg", dst);        //resize(dst, dst1, Size(dst.cols / 4, dst.rows / 4), 0, 0, INTER_LINEAR);        //imshow("中间结果", dst1);        circle(g_srcImage, Point(center.x, center.y), 5, Scalar(0, 225, 0), 2, 3);//画圆        con.pop_back();        itr++;    }    resize(g_srcImage, g_srcImage1, Size(g_srcImage.cols / 4, g_srcImage.rows / 4), 0, 0, INTER_LINEAR);    //更新效果图    imshow(WINDOW_NAME, g_srcImage1);    //imwrite("s_pos71_run7_img190.jpg", g_srcImage);}

实验结果