opencv之轮廓最小外接矩形和最小外接圆

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我是靠谱客的博主不安饼干，这篇文章主要介绍opencv之轮廓最小外接矩形和最小外接圆，现在分享给大家，希望可以做个参考。

转载自：http://blog.csdn.net/dcrmg/article/details/52260699

OpenCV中求点集的最小外结矩使用方法minAreaRect，求点集的最小外接圆使用方法minEnclosingCircle。

minAreaRect方法原型：

RotatedRect minAreaRect( InputArray points );

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RotatedRect minAreaRect( InputArray points );

输入参数points是所要求最小外结矩的 点集数组或向量；

minEnclosingCircle方法原型：

void minEnclosingCircle( InputArray points,
CV_OUT Point2f& center, CV_OUT float& radius );

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void minEnclosingCircle( InputArray points,
CV_OUT Point2f& center, CV_OUT float& radius );

第一个参数points是所要求最小外结圆的点集数组或向量；

第二个参数Point2f类型的center是求得的最小外接圆的中心坐标；

第三个参数float类型的radius是求得的最小外接圆的半径；

使用minAreaRect和minEnclosingCircle方法分别求最小外接矩和圆：

[cpp] view plain copy print ?

<span style="font-size:18px;">#include "core/core.hpp"
#include "highgui/highgui.hpp"
#include "imgproc/imgproc.hpp"
#include "iostream"
using namespace std;
using namespace cv;
int main(int argc,char *argv[])
{
Mat imageSource=imread(argv[1],0);
imshow("Source Image",imageSource);
Mat image;
blur(imageSource,image,Size(3,3));
threshold(image,image,0,255,CV_THRESH_OTSU);
imshow("Threshold Image",image);
//寻找最外层轮廓
vector<vector<Point>> contours;
vector<Vec4i> hierarchy;
findContours(image,contours,hierarchy,RETR_EXTERNAL,CHAIN_APPROX_NONE,Point());
Mat imageContours=Mat::zeros(image.size(),CV_8UC1); //最小外接矩形画布
Mat imageContours1=Mat::zeros(image.size(),CV_8UC1); //最小外结圆画布
for(int i=0;i<contours.size();i++)
{
//绘制轮廓
drawContours(imageContours,contours,i,Scalar(255),1,8,hierarchy);
drawContours(imageContours1,contours,i,Scalar(255),1,8,hierarchy);
//绘制轮廓的最小外结矩形
RotatedRect rect=minAreaRect(contours[i]);
Point2f P[4];
rect.points(P);
for(int j=0;j<=3;j++)
{
line(imageContours,P[j],P[(j+1)%4],Scalar(255),2);
}
//绘制轮廓的最小外结圆
Point2f center; float radius;
minEnclosingCircle(contours[i],center,radius);
circle(imageContours1,center,radius,Scalar(255),2);
}
imshow("MinAreaRect",imageContours);
imshow("MinAreaCircle",imageContours1);
waitKey(0);
return 0;
}</span>

复制代码

<span style="font-size:18px;">#include "core/core.hpp"
#include "highgui/highgui.hpp"
#include "imgproc/imgproc.hpp"
#include "iostream"
using namespace std;
using namespace cv;
int main(int argc,char *argv[])
{
Mat imageSource=imread(argv[1],0);
imshow("Source Image",imageSource);
Mat image;
blur(imageSource,image,Size(3,3));
threshold(image,image,0,255,CV_THRESH_OTSU);
imshow("Threshold Image",image);
//寻找最外层轮廓
vector<vector<Point>> contours;
vector<Vec4i> hierarchy;
findContours(image,contours,hierarchy,RETR_EXTERNAL,CHAIN_APPROX_NONE,Point());
Mat imageContours=Mat::zeros(image.size(),CV_8UC1);	//最小外接矩形画布
Mat imageContours1=Mat::zeros(image.size(),CV_8UC1); //最小外结圆画布
for(int i=0;i<contours.size();i++)
{
//绘制轮廓
drawContours(imageContours,contours,i,Scalar(255),1,8,hierarchy);
drawContours(imageContours1,contours,i,Scalar(255),1,8,hierarchy);
//绘制轮廓的最小外结矩形
RotatedRect rect=minAreaRect(contours[i]);
Point2f P[4];
rect.points(P);
for(int j=0;j<=3;j++)
{
line(imageContours,P[j],P[(j+1)%4],Scalar(255),2);
}
//绘制轮廓的最小外结圆
Point2f center; float radius;
minEnclosingCircle(contours[i],center,radius);
circle(imageContours1,center,radius,Scalar(255),2);
}
imshow("MinAreaRect",imageContours);
imshow("MinAreaCircle",imageContours1);
waitKey(0);
return 0;
}</span>

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<span style="font-size:18px;">#include "core/core.hpp"
#include "highgui/highgui.hpp"
#include "imgproc/imgproc.hpp"
#include "iostream"
using namespace std;
using namespace cv;
int main(int argc,char *argv[])
{
Mat imageSource=imread(argv[1],0);
imshow("Source Image",imageSource);
Mat image;
blur(imageSource,image,Size(3,3));
threshold(image,image,0,255,CV_THRESH_OTSU);
imshow("Threshold Image",image);
//寻找最外层轮廓
vector<vector<Point>> contours;
vector<Vec4i> hierarchy;
findContours(image,contours,hierarchy,RETR_EXTERNAL,CHAIN_APPROX_NONE,Point());
Mat imageContours=Mat::zeros(image.size(),CV_8UC1);	//最小外接矩形画布
Mat imageContours1=Mat::zeros(image.size(),CV_8UC1); //最小外结圆画布
for(int i=0;i<contours.size();i++)
{
//绘制轮廓
drawContours(imageContours,contours,i,Scalar(255),1,8,hierarchy);
drawContours(imageContours1,contours,i,Scalar(255),1,8,hierarchy);
//绘制轮廓的最小外结矩形
RotatedRect rect=minAreaRect(contours[i]);
Point2f P[4];
rect.points(P);
for(int j=0;j<=3;j++)
{
line(imageContours,P[j],P[(j+1)%4],Scalar(255),2);
}
//绘制轮廓的最小外结圆
Point2f center; float radius;
minEnclosingCircle(contours[i],center,radius);
circle(imageContours1,center,radius,Scalar(255),2);
}
imshow("MinAreaRect",imageContours);
imshow("MinAreaCircle",imageContours1);
waitKey(0);
return 0;
}</span>