【OpenCV笔记 15-1】OpenCV寻找物体的凸包convexHull

OpenCV寻找物体的凸包convexHull()

应用到的知识点：

1.寻找物体的凸包convexHull
2.定义和输出vector容器点坐标

3.随机数发生器

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凸包检测示例程序：

//寻找物体的凸包convexHull//定义和输出vector容器点坐标#include <opencv2/opencv.hpp>#include "opencv2/highgui/highgui.hpp"#include "opencv2/imgproc/imgproc.hpp"#include <vector>using namespace std;using namespace cv;int main(int argc, char** argv){Mat testImage(600, 600, CV_8UC3);//画布大小600x600RNG& rng = theRNG();//按回车键一直更新while (1){//int count = (unsigned)rng % 100 + 8;//随机生成点的数量int count = rng.uniform(5, 20);//随机产生点的个数cout << "凸包包含 " << count << " 个点" << endl;cout << "各点坐标如下：" << endl;//输出产生随机点个数vector<Point>points;//vector容器存放点坐标for (int i = 0; i < count; i++){Point point;//点坐标随机产生point.x = rng.uniform(testImage.cols / 5, testImage.cols * 4 / 5); //横坐标x在范围（600/1，600*4/5）随机产生point.y = rng.uniform(testImage.rows / 4, testImage.rows * 3 / 4);//纵坐标y在范围（600/4，600*3/4）随机产生points.push_back(point);cout << "Point" << i + 1 << ": " << point << endl;//依次输出随机产生每个点的坐标}cout << "基于Mat的vector:\n" << Mat(points) << endl;//基于Mat类的vector将以矩阵形式输出坐标//检测凸包vector<int >hull;convexHull(Mat(points), hull, true);testImage = Scalar::all(0);//将画布设置为黑色for (int i = 0; i < count; i++)circle(testImage, points[i], 5, Scalar(255, 0, 255), -1, 4);//以随机点为圆心，画出半径为5的实心圆（标记作用）//参数准备int hullcout = (int)hull.size();//凸包的边数Point point0 = points[hull[hullcout - 1]];//连接凸包的坐标点//依次连接随机点，绘制凸包for (int i = 0; i < hullcout; i++){Point point = points[hull[i]];line(testImage, point0, point, Scalar(0, 255, 255), 1, 4);//连接线条颜色为黄色point0 = point;}//输出imshow("凸包绘制检测", testImage);char key;key = (char)waitKey();if (key == 27 || key == 'q' || key == 'Q')//按下ESC 或q 或 Q 退出break;}return 0;}

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运行结果：

运行结果1

注意比较两种坐标的输出格式，一个是std::vector格式，另一种是基于Mat的vector格式（矩阵形式）。

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运行结果2

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运行结果3