查找轮廓+寻找凸包

#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include <iostream>

using namespace cv;
using namespace std;

#define WINDOW_NAME1 "【原始图窗口】"                    
#define WINDOW_NAME2 "【效果图窗口】"                

Mat g_srcImage; Mat g_grayImage;
int g_nThresh = 50;
int g_maxThresh = 255;
RNG g_rng(12345);
Mat srcImage_copy = g_srcImage.clone();
Mat g_thresholdImage_output;
vector<vector<Point> > g_vContours;
vector<Vec4i> g_vHierarchy;

void on_ThreshChange(int, void*);
void ShowHelpText();

int main()
{
    g_srcImage = imread("0.PNG", 1);

    cvtColor(g_srcImage, g_grayImage, COLOR_BGR2GRAY);
    blur(g_grayImage, g_grayImage, Size(3, 3));

    imshow(WINDOW_NAME1, g_srcImage);

    createTrackbar(" 阈值:", WINDOW_NAME1, &g_nThresh, g_maxThresh, on_ThreshChange);
    on_ThreshChange(0, 0);

    waitKey(0);
    return(0);
}

void on_ThreshChange(int, void*)
{
    threshold(g_grayImage, g_thresholdImage_output, g_nThresh, 255, THRESH_BINARY);

    findContours(g_thresholdImage_output, g_vContours, g_vHierarchy, RETR_TREE, CHAIN_APPROX_SIMPLE, Point(0, 0));

    vector<vector<Point> >hull(g_vContours.size());
    for (unsigned int i = 0; i < g_vContours.size(); i++)
    {
        convexHull(Mat(g_vContours[i]), hull[i], false);
    }

    Mat drawing = Mat::zeros(g_thresholdImage_output.size(), CV_8UC3);
    for (unsigned int i = 0; i < g_vContours.size(); i++)
    {
        Scalar color = Scalar(g_rng.uniform(0, 255), g_rng.uniform(0, 255), g_rng.uniform(0, 255));
        //drawContours(drawing, g_vContours, i, color, 1, 8, vector<Vec4i>(), 0, Point());
        drawContours(drawing, hull, i, color, 1, 8, vector<Vec4i>(), 0, Point());
    }

    imshow(WINDOW_NAME2, drawing);
}