【OpenCV筆記 15-1】OpenCV尋找物體的凸包convexHull

原創

地灯

2020-02-22 15:10

OpenCV尋找物體的凸包convexHull()

應用到的知識點：

1.尋找物體的凸包convexHull
2.定義和輸出vector容器點座標

3.隨機數發生器

==================================

凸包檢測示例程序：

//尋找物體的凸包convexHull
//定義和輸出vector容器點座標

#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);//畫布大小600x600
	RNG& rng = theRNG();
	//按回車鍵一直更新
	while (1)
	{
		//int count = (unsigned)rng % 100 + 8;//隨機生成點的數量
		int count = rng.uniform(5, 20);//隨機產生點的個數
		cout << "凸包包含 " << count << " 個點" << endl;
		cout << "各點座標如下：" << endl;//輸出產生隨機點個數
		vector<Point>points;//vector容器存放點座標

		for (int i = 0; i < count; i++)
		{
			Point point;
			//點座標隨機產生
			point.x = rng.uniform(testImage.cols / 5, testImage.cols * 4 / 5); //橫座標x在範圍（600/1，600*4/5）隨機產生
			point.y = rng.uniform(testImage.rows / 4, testImage.rows * 3 / 4);//縱座標y在範圍（600/4，600*3/4）隨機產生
			points.push_back(point);
			cout << "Point" << i + 1 << ": " << point << endl;//依次輸出隨機產生每個點的座標
		}

		cout << "基於Mat的vector:\n" << Mat(points) << endl;//基於Mat類的vector將以矩陣形式輸出座標

		//檢測凸包
		vector<int >hull;
		convexHull(Mat(points), hull, true);

		testImage = Scalar::all(0);//將畫布設置爲黑色
		for (int i = 0; i < count; i++)
			circle(testImage, points[i], 5, Scalar(255, 0, 255), -1, 4);//以隨機點爲圓心，畫出半徑爲5的實心圓（標記作用）
		//參數準備
		int hullcout = (int)hull.size();//凸包的邊數
		Point point0 = points[hull[hullcout - 1]];//連接凸包的座標點
		//依次連接隨機點，繪製凸包
		for (int i = 0; i < hullcout; i++)
		{
			Point point = points[hull[i]];
			line(testImage, point0, point, Scalar(0, 255, 255), 1, 4);//連接線條顏色爲黃色
			point0 = point;
		}
		//輸出
		imshow("凸包繪製檢測", 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;
}

==================================