opencv——通过面积筛选最大轮廓，并求凸包矩形的长和宽

#include "stdafx.h"
#include <iostream>
#include<string>
#include <stdio.h>
#include <cv.h>
#include <highgui.h>
#include <cxcore.h>
#include <stdio.h>

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
   IplImage* src=cvLoadImage("3.jpg",0);
   
   IplImage* des=cvCreateImage(cvGetSize(src),src->depth,src->nChannels);
    cvZero(des);
   cvThreshold(src,src,0,150,CV_THRESH_BINARY);
   CvMemStorage* memory=cvCreateMemStorage(0);
   CvSeq* Icontour=NULL;
   CvSeq* maxContour =NULL;
   cvShowImage("原始图像1",src);
   cvFindContours(src,memory,&Icontour, sizeof(CvContour),CV_RETR_LIST,CV_CHAIN_APPROX_SIMPLE,cvPoint(0,0));
   double area=0;
   double maxArea=0;
   while(Icontour)
   {
       area=fabs(cvContourArea(Icontour,CV_WHOLE_SEQ));
       cvDrawContours(src, Icontour,
           CV_RGB(255,255,255), CV_RGB(255, 255,255),
           0, 1, 8, cvPoint(0,0));
        
       if(area>200 && area<400)
       {
           
           maxContour = Icontour;
       }
       Icontour =Icontour->h_next;
   }
    
   cvDrawContours(des, maxContour,
   CV_RGB(255,255,255), CV_RGB(255, 255,255), 0, 1, 8, cvPoint(0,0));
   //CvRect rect=cvBoundingRect(maxContour,0);
   CvBox2D box=cvMinAreaRect2(maxContour);
   cout<<"长度： "<<box.size.width<<endl<<"宽度： "<<box.size.height;
   //cvRectangle(src,cvPoint((rect.x-rect.height/2),(rect.y-rect.width/2)),cvPoint((rect.x+rect.height/2),(rect.y+rect.width/2)),cvScalar(255,255,255),1,8,0);
  // cvRectangle(src,cvPoint((rect.x-rect.height/2),(rect.y-rect.width/2)),cvPoint((rect.x-rect.height/2),(rect.y-rect.width/2)),cvScalar(255,255,255),2,8,0);
  // cvDrawCircle(src,cvPoint(box.center.x,box.center.y),box.size.height,cvScalar(255,255,255),2,8,0);
   
 
     CvPoint2D32f p4[4];
     cvBoxPoints(box,p4);
     cvLine(des, cvPoint(cvRound(p4[0].x), cvRound(p4[0].y)),
     cvPoint(cvRound(p4[1].x), cvRound(p4[1].y)), CV_RGB(0, 0, 255),2);
       
     cvLine(des, cvPoint(cvRound(p4[1].x), cvRound(p4[1].y)),
     cvPoint(cvRound(p4[2].x), cvRound(p4[2].y)), CV_RGB(0, 0, 255),2);
       
     cvLine(des, cvPoint(cvRound(p4[3].x), cvRound(p4[3].y)),
     cvPoint(cvRound(p4[2].x), cvRound(p4[2].y)), CV_RGB(0,0, 255),2);
       
     cvLine(des, cvPoint(cvRound(p4[3].x), cvRound(p4[3].y)),
     cvPoint(cvRound(p4[0].x), cvRound(p4[0].y)), CV_RGB(0, 0,255),2);
       
  
   cvShowImage("原始图像",src);
   cvShowImage("保留最大值",des);
   cvWaitKey(0);
   //cvReleaseImage(&src);  
   cvDestroyWindow("原始图像"); 
   return 0;
}