OpenCV学习——椭圆拟合

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#include "cv.h"
#include "highgui.h"

int slider_pos=70;//阈值

IplImage *image02 =0,*image03 = 0,*image04 = 0;
void process_image(int h);

int main(int argc ,char **argv)
{
const char *filename ="rice.png";
if ((image03 = cvLoadImage(filename,0))==0)//读入图像为灰度图像
{
return -1;
}
image02 = cvCloneImage(image03);
image04 = cvCloneImage(image03);

cvNamedWindow("Source",1);
cvNamedWindow("Result",1);

cvShowImage("Source",image03);

cvCreateTrackbar("Threshold","Result",&slider_pos,255,process_image);

process_image(0);

cvWaitKey(0);
cvSaveImage("1.jpg",image04);

cvReleaseImage(&image02);
cvReleaseImage(&image03);

cvDestroyWindow("Source");
cvDestroyWindow("Result");
return 0;

}

//这个函数寻找出轮廓、用椭圆拟合画出
void process_image(int h)
{
CvMemStorage *stor;
CvSeq *cont;
CvBox2D32f *box;
CvPoint *PointArray;
CvPoint2D32f *PointArray2D32f;

stor = cvCreateMemStorage(0);
cont = cvCreateSeq(CV_SEQ_ELTYPE_POINT,sizeof(CvSeq),sizeof(CvPoint),stor);

cvThreshold(image03,image02,slider_pos,255,CV_THRESH_BINARY);

cvFindContours(image02,stor,&cont,sizeof(CvContour),
CV_RETR_LIST,CV_CHAIN_APPROX_NONE,cvPoint(0,0));

cvZero(image02);
cvZero(image04);

//绘制所有轮廓并用椭圆拟合
for (;cont;cont = cont ->h_next)
{
int i;
int count= cont->total;//轮廓个数
CvPoint center;
CvSize size;

/*个数必须大于6，这是cvFitEllipse_32f的要求*/
if (count<6)
{
continue;
}

//分配内存给点集
PointArray = (CvPoint *)malloc(count*sizeof(CvPoint));
PointArray2D32f = (CvPoint2D32f*)malloc(count*sizeof(CvPoint2D32f));

//分配内存给椭圆数据
box = (CvBox2D32f *)malloc(sizeof(CvBox2D32f));

//得到点集（这个方法值得借鉴）
cvCvtSeqToArray(cont,PointArray,CV_WHOLE_SEQ);

//将CvPoint点集转化为CvBox2D32f集合
for (i=0;i<count;i++)
{
PointArray2D32f[i].x=(float)PointArray[i].x;
PointArray2D32f[i].y=(float)PointArray[i].y;
}

//拟合当前轮廓
cvFitEllipse(PointArray2D32f,count,box);

//绘制当前轮廓
cvDrawContours(image04,cont,CV_RGB(255,255,255),CV_RGB(255,255,255),
0,1,8,cvPoint(0,0));

//将椭圆数据从浮点转化为整数表示
center.x = cvRound(box->center.x);
center.y = cvRound(box->center.y);
size.width = cvRound(box->size.width*0.5);
size.height = cvRound(box->size.height*0.5);
box->angle = -box->angle;

//画椭圆
cvEllipse(image04,center,size,box->angle,0,360,CV_RGB(0,0,255),1,CV_AA,0);

free(PointArray);
free(PointArray2D32f);
free(box);
}
cvShowImage("Result",image04);
}