cvCalcOpticalFlowPyrLK 需要确定特征点。
本程序，通过帧差获得运动的点作为特征点。
本程序原本的目的是计算运动点的速度，通过修正可以进行运动跟踪。
- #include <cv.h>
- #include <highgui.h>
- #include <iostream>
- using namespace std;
- int const MAX_CORNERS = 1000;
- int main (int argc, char **argv)
- {
- CvCapture* capture = 0;
- capture = cvCaptureFromCAM( CV_CAP_ANY ); //get frame
- IplImage *src_img1; //the previous frame (gray)
- IplImage *src_img2; //the current frame(gray)
- IplImge *dst_img; //the result
- IplImage *cur_img;
- IplImage *pre_img;
- CvPoint2D32f * move_old_point = new CvPoint2D32f[ MAX_CORNERS];
- CvPoint2D32f * move_new_point = new CvPoint2D32f[ MAX_CORNERS];
- char *features_found = new char[MAX_CORNERS];
- float *features_error = new float[MAX_CORNERS];
- CvTermCriteria criteria;
- criteria = cvTermCriteria (CV_TERMCRIT_ITER | CV_TERMCRIT_EPS, 64, 0.01);
- while(1)
- {
- int i,j;
- int dx, dy;
- int p = 0;
- int rows, cols;
- int countn = MAX_CORNERS;
- pre_img = cvQueryFrame(capture);
- CvSize img_sz = cvGetSize(pre_img);
- src_img1 = cvCreateImage(img_sz, IPL_DEPTH_8U, 1);
- cvCvtColor(pre_img, src_img1, CV_RGB2GRAY);
- cur_img = cvQueryFrame(capture);
- src_img2 = cvCreateImage(img_sz, IPL_DEPTH_8U, 1);
- cvCvtColor(cur_img, src_img2, CV_RGB2GRAY);
- dst_img = (IplImage *)cvClone(cur_img);
- IplImage *move_img = cvCreateImage(img_sz, IPL_DEPTH_8U, 1);
- cvZero(move_img);
- //cvAbsDiff(src_img1, src_img2,move_img);
- cols = src_img1->width;
- rows = src_img1->height;
- for (i = 0; i <cols; i++)
- {
- for (j = 0; j<rows; j++)
- {
- double a = abs(cvGet2D(src_img1, j, i).val[0]-cvGet2D(src_img2, j, i).val[0]);
- CvScalar b = cvScalar(a, 0, 0,0);
- cvSet2D(move_img, j, i,b);
- if (a>40)
- {
- if (p<MAX_CORNERS-1)
- {
- int d = ++p;
- move_old_point[d].x = i;
- move_old_point[d].y = j;
- }
- }
- }
- }
- cvNamedWindow("moving object", 1);
- cvShowImage("moving object", move_img);
- CvSize Pyrsize = cvSize(src_img1->width +8, src_img1->height/3);
- IplImage * pyrA = cvCreateImage(Pyrsize, IPL_DEPTH_32F, 1); //pyrA是需要寻找的点，不是没有初始化的
- IplImage * pyrB = cvCreateImage(Pyrsize, IPL_DEPTH_32F, 1);
- cvCalcOpticalFlowPyrLK(src_img1,
- src_img2,
- pyrA,
- pyrB,
- move_old_point,
- move_new_point,
- countn,
- cvSize(10, 10),
- 3,
- features_found,
- features_error,
- criteria,
- 0
- );
- for (i = 0; i < countn; i++)
- {
- int x1 = (int)move_new_point[i].x;
- int x2 = (int)move_old_point[i].x;
- int y1 = (int)move_new_point[i].y;
- int y2 = (int)move_old_point[i].y;
- dx =(int) abs(x1 - x2) ;
- dy = (int)abs(y1 - y2);
- if (dx >= 5&& dy >= 5)
- {
- cvLine (dst_img, cvPoint(x2, y2),cvPoint(x2+5, y2+5) , CV_RGB (255, 0, 0), 1, CV_AA, 0);
- }
- }
- cvNamedWindow ("ImagePyrLK", 1);
- cvShowImage ("ImagePyrLK", dst_img);
- cvWaitKey (1);
- cvReleaseImage (&dst_img);
- cvReleaseImage(&pyrA);
- cvReleaseImage(&pyrB);
- cvReleaseImage(&move_img);
- }
- cvDestroyWindow("moving object");
- cvDestroyWindow ("ImagePyrLK");
- cvReleaseImage (&src_img1);
- cvReleaseImage (&src_img2);
- cvReleaseImage (&pre_img);
- cvReleaseImage (&cur_img);
- return 0;
- }
