OpenCV23在一个物体上绘制椭圆与矩形_轮廓周围绘制矩形

/*OpenCV23在一个物体上绘制椭圆与矩形_轮廓周围绘制矩形 by txwtech

轮廓周围绘制矩形 -API

approxPolyDP(InputArray  curve, OutputArray approxCurve,  double  epsilon,  bool  closed)

基于RDP算法实现,目的是减少多边形轮廓点数

 

cv::boundingRect(InputArray points)

 

得到轮廓周围最小矩形左上交点坐标和右下角点坐标，绘制一个矩形

cv::minAreaRect(InputArray  points)

 

得到一个旋转的矩形，返回旋转矩形

轮廓周围绘制圆和椭圆-API cv::minEnclosingCircle(InputArray points, //得到最小区域圆形 Point2f& center, // 圆心位置 float& radius)// 圆的半径 cv::fitEllipse(InputArray  points)得到最小椭圆

 

实现过程：

1.将图像变为二值图像 2.发现轮廓，找到图像轮廓 3.通过相关API在轮廓点上找到最小包含矩形和圆，旋转矩形与椭圆。 4.绘制出来

--------------------------- Microsoft Visual C++ Runtime Library --------------------------- Debug Assertion Failed!

Program: C:\windows\SYSTEM32\MSVCP140D.dll File: c:\program files (x86)\microsoft visual studio 14.0\vc\include\vector Line: 1234

Expression: vector subscript out of range

For information on how your program can cause an assertion failure, see the Visual C++ documentation on asserts.

(Press Retry to debug the application)

--------------------------- 中止(A)   重试(R)   忽略(I) --------------------------- vector contours_ploy();//这样就是没有赋初值，报错

vector contours_ploy(contours.size());//这样就Ok

*/

#include 
#include 
using namespace std;
using namespace cv;

Mat src;
Mat src_gray;
Mat draw_image;
int threshold_min = 90;
int threshold_max = 255;
const char* out_window = "矩形输出结果";
RNG rng(12345);
void Contours_Func(int, void*);
int main(int argc, char *argv[])
{
	src = imread("e:\\pictures\\热气球.jpg",CV_LOAD_IMAGE_COLOR);
	if (!src.data)
	{
		printf("failed to load image");
		return -1;
	}
	//namedWindow("原图",CV_WINDOW_AUTOSIZE);
	//imshow("原图",src);
	//转灰度图像
	cvtColor(src, src_gray, CV_BGR2GRAY);
	//模糊
	blur(src_gray,src_gray,Size(3,3),Point(-1,-1));
	const char* src_window = "原图";
	namedWindow(src_window,CV_WINDOW_AUTOSIZE);
	namedWindow(out_window,CV_WINDOW_AUTOSIZE);
	imshow(src_window,src);

	createTrackbar("threshold:",out_window,&threshold_min,threshold_max,Contours_Func);

	Contours_Func(0,0);
	waitKey(0);
	
	return 0;
}
void Contours_Func(int, void*)
{
	Mat binary_output;//二值图像
	vector contours;
	vector hierachy;
	//阈值处理
	threshold(src_gray,binary_output,threshold_min,threshold_max,THRESH_BINARY);
	//发现轮廓
	findContours(binary_output,contours,RETR_TREE,CHAIN_APPROX_SIMPLE,Point(-1,-1));
    
	vector contours_ploy(contours.size());//外接多边形
	//找出最小矩形
	vector ploy_rects(contours.size());;
	vector ccs(contours.size());//圆心
	vector radius(contours.size());//半径

	vector minRect(contours.size());
	vector myellipse(contours.size());
	for (size_t i = 0; i < contours.size(); i++)
	{
		//true就是绘制封闭矩形
		approxPolyDP(Mat(contours[i]),contours_ploy[i],3,true);
		ploy_rects[i] = boundingRect(contours_ploy[i]);
		minEnclosingCircle(contours_ploy[i],ccs[i],radius[i]);

		if (contours_ploy[i].size() > 5)
		{
		myellipse[i] = fitEllipse(contours_ploy[i]);
		minRect[i] = minAreaRect(contours_ploy[i]);
					
		}

	}
	//src.copyTo(draw_image);//原图上画椭圆与矩形
	draw_image = Mat::zeros(src.size(),src.type());//此句为在空白模板画
	Point2f pts[4];

	for (size_t t = 0; t < contours.size(); t++)
	{
		Scalar color = Scalar(rng.uniform(0,255), rng.uniform(0, 255), rng.uniform(0, 255));
		//rectangle(draw_image,ploy_rects[t],color,2,8);
		//circle(draw_image,ccs[t],radius[t],color,2,8);

		if (contours_ploy[t].size() > 5)
		{ 
			//画椭圆
		ellipse(draw_image,myellipse[t],color,1,8);
		minRect[t].points(pts);

		//画4条线就是矩形
		for (int r = 0; r < 4; r++)
		{
			line(draw_image,pts[r],pts[(r+1)%4],color,1,8);
		}
		}
	}
	//imshow(out_window, draw_image);//正常显示
	imshow(out_window,~draw_image);//反色显示
		
}