OpenCV 求外接矩形以及旋转角度
程序没有写完整，大概功能就是实现了，希望大家分享学习，把他改对
// FindRotation-angle.cpp : 定义控制台应用程序的入口点。
//
// findContours.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
#include <iostream>
#include <vector>
#include <opencv2/opencv.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/highgui/highgui.hpp>
#pragma comment(lib,"opencv_core2410d.lib")
#pragma comment(lib,"opencv_highgui2410d.lib")
#pragma comment(lib,"opencv_imgproc2410d.lib")
#define PI 3.1415926
int main()
{
// Read input binary image
char *image_name = "test2.jpg";
cv::Mat image = cv::imread(image_name,0);
if (!image.data)
return 0;
cv::namedWindow("Binary Image");
cv::imshow("Binary Image",image);
// 从文件中加载原图
IplImage *pSrcImage = cvLoadImage(image_name, CV_LOAD_IMAGE_UNCHANGED);
// 转为2值图
cvThreshold(pSrcImage,pSrcImage,200,255,cv::THRESH_BINARY_INV);
image = cv::Mat(pSrcImage,true);
cv::imwrite("binary.jpg",image);
// Get the contours of the connected components
std::vector<std::vector<cv::Point>> contours;
cv::findContours(image,
contours, // a vector of contours
CV_RETR_EXTERNAL, // retrieve the external contours
CV_CHAIN_APPROX_NONE); // retrieve all pixels of each contours
// Print contours' length
std::cout << "Contours: " << contours.size() << std::endl;
std::vector<std::vector<cv::Point>>::const_iterator itContours= contours.begin();
for ( ; itContours!=contours.end(); ++itContours)
{
std::cout << "Size: " << itContours->size() << std::endl;
}
// draw black contours on white image
cv::Mat result(image.size(),CV_8U,cv::Scalar(255));
cv::drawContours(result,contours,
-1, // draw all contours
cv::Scalar(0), // in black
2); // with a thickness of 2
cv::namedWindow("Contours");
cv::imshow("Contours",result);
// Eliminate too short or too long contours
int cmin= 100; // minimum contour length
int cmax= 1000; // maximum contour length
std::vector<std::vector<cv::Point>>::const_iterator itc= contours.begin();
while (itc!=contours.end()) {
if (itc->size() < cmin || itc->size() > cmax)
itc= contours.erase(itc);
else
++itc;
}
// draw contours on the original image
cv::Mat original= cv::imread(image_name);
cv::drawContours(original,contours,
-1, // draw all contours
cv::Scalar(255,255,0), // in white
2); // with a thickness of 2
cv::namedWindow("Contours on original");
cv::imshow("Contours on original",original);
// Let's now draw black contours on white image
result.setTo(cv::Scalar(255));
cv::drawContours(result,contours,
-1, // draw all contours
cv::Scalar(0), // in black
1); // with a thickness of 1
image= cv::imread("binary.jpg",0);
// testing the bounding box
std::vector<std::vector<cv::Point>>::const_iterator itc_rec= contours.begin();
while (itc_rec!=contours.end())
{
cv::Rect r0= cv::boundingRect(cv::Mat(*(itc_rec)));
cv::rectangle(result,r0,cv::Scalar(0),2);
++itc_rec;
}
cv::namedWindow("Some Shape descriptors");
cv::imshow("Some Shape descriptors",result);
CvBox2D End_Rage2D;
CvMemStorage *storage = cvCreateMemStorage(0); //开辟内存空间
CvSeq* contour = NULL; //CvSeq类型 存放检测到的图像轮廓边缘所有的像素值，坐标值特征的结构体以链表形式
cvFindContours( pSrcImage, storage, &contour, sizeof(CvContour),CV_RETR_CCOMP, CV_CHAIN_APPROX_NONE);//这函数可选参数还有不少
for(; contour; contour = contour->h_next) //如果contour不为空，表示找到一个以上轮廓，这样写法只显示一个轮廓
//如改为for(; contour; contour = contour->h_next) 就可以同时显示多个轮廓
{
End_Rage2D = cvMinAreaRect2(contour); //代入cvMinAreaRect2这个函数得到最小包围矩形 这里已得出被测物体的角度，宽度,高度，和中点坐标点存放在CvBox2D类型的结构体中，主要工作基本结束。
std::cout <<" angle:\n"<<(float)End_Rage2D.angle << std::endl; //被测物体旋转角度
}
cv::waitKey();
return 0;
}
重新写了一下这个代码，还是稍微有点小问题，希望大家共同探讨：
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