OpenCV学习之椭圆曲线拟合

程序首先发现图像的轮廓，然后用椭圆逼近它。

//椭圆曲线拟合#include "cv.h"#include "highgui.h"int slider_pos = 70;IplImage *image02 = 0, *image03 = 0, *image04 = 0;void process_image(int h);int main(int argc, char** argv){    // 读入图像，强制为灰度图像    image03 = cvLoadImage("corner.tif", 0);    // Create the destination images    image02 = cvCloneImage(image03);    image04 = cvCloneImage(image03);    // Create windows.    cvNamedWindow("Source", 1);    cvNamedWindow("Result", 1);    // Show the image.    cvShowImage("Source", image03);    // Create toolbars. HighGUI use.    cvCreateTrackbar("Threshold", "Result", &slider_pos, 255, process_image);    process_image(0);    // Wait for a key stroke; the same function arranges events processing                    cvWaitKey(0);    cvReleaseImage(&image02);    cvReleaseImage(&image03);    cvDestroyWindow("Source");    cvDestroyWindow("Result");    return 0;}// Define trackbar callback functon. This function find contours,// draw it and approximate it by ellipses.void process_image(int h){    CvMemStorage* stor;    CvSeq* cont;    CvBox2D32f* box;    CvPoint* PointArray;    CvPoint2D32f* PointArray2D32f;    // 创建动态结构序列    stor = cvCreateMemStorage(0);    cont = cvCreateSeq(CV_SEQ_ELTYPE_POINT, sizeof(CvSeq), sizeof(CvPoint), stor);    // 二值话图像.    cvThreshold(image03, image02, slider_pos, 255, CV_THRESH_BINARY);    // 寻找所有轮廓.    cvFindContours(image02, stor, &cont, sizeof(CvContour),        CV_RETR_LIST, CV_CHAIN_APPROX_NONE, cvPoint(0, 0));    // Clear images. IPL use.    cvZero(image02);    cvZero(image04);    // 本循环绘制所有轮廓并用椭圆拟合.    for (; cont; cont = cont->h_next)    {        int i; // Indicator of cycle.        int count = cont->total; // This is number point in contour        CvPoint center;        CvSize size;        // Number point must be more than or equal to 6 (for cvFitEllipse_32f).                if (count < 6)            continue;        // Alloc memory for contour point set.            PointArray = (CvPoint*)malloc(count * sizeof(CvPoint));        PointArray2D32f = (CvPoint2D32f*)malloc(count * sizeof(CvPoint2D32f));        // Alloc memory for ellipse data.        box = (CvBox2D32f*)malloc(sizeof(CvBox2D32f));        // Get contour point set.        cvCvtSeqToArray(cont, PointArray, CV_WHOLE_SEQ);        // Convert CvPoint set to CvBox2D32f set.        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));        // Convert ellipse data from float to integer representation.        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;        // Draw ellipse.        cvEllipse(image04, center, size,            box->angle, 0, 360,            CV_RGB(0, 0, 255), 1, CV_AA, 0);        // Free memory.                  free(PointArray);        free(PointArray2D32f);        free(box);    }    // Show image. HighGUI use.    cvShowImage("Result", image04);}