samples/c/fback_c.c

   1 #include <opencv2/video/tracking.hpp>
   2 #include <opencv2/highgui/highgui.hpp>
   3
   4 void drawOptFlowMap(const CvMat* flow, CvMat* cflowmap, int step,
   5                     double scale, CvScalar color)
   6 {
   7     int x, y;
   8     for( y = 0; y < cflowmap->rows; y += step)
   9         for( x = 0; x < cflowmap->cols; x += step)
  10         {
  11             CvPoint2D32f fxy = CV_MAT_ELEM(*flow, CvPoint2D32f, y, x);
  12             cvLine(cflowmap, cvPoint(x,y), cvPoint(cvRound(x+fxy.x), cvRound(y+fxy.y)),
  13                  color, 1, 8, 0);
  14             cvCircle(cflowmap, cvPoint(x,y), 2, color, -1, 8, 0);
  15         }
  16 }
  17
  18 int main(int argc, char** argv)
  19 {
  20     CvCapture* capture = cvCreateCameraCapture(0);
  21     CvMat* prevgray = 0, *gray = 0, *flow = 0, *cflow = 0;
  22
  23     if( !capture )
  24         return -1;
  25
  26     cvNamedWindow("flow", 1);
  27
  28     for(;;)
  29     {
  30         int firstFrame = gray == 0;
  31         IplImage* frame = cvQueryFrame(capture);
  32         if(!frame)
  33             break;
  34         if(!gray)
  35         {
  36             gray = cvCreateMat(frame->height, frame->width, CV_8UC1);
  37             prevgray = cvCreateMat(gray->rows, gray->cols, gray->type);
  38             flow = cvCreateMat(gray->rows, gray->cols, CV_32FC2);
  39             cflow = cvCreateMat(gray->rows, gray->cols, CV_8UC3);
  40         }
  41         cvCvtColor(frame, gray, CV_BGR2GRAY);
  42
  43         if( !firstFrame )
  44         {
  45             cvCalcOpticalFlowFarneback(prevgray, gray, flow, 0.5, 3, 15, 3, 5, 1.2, 0);
  46             cvCvtColor(prevgray, cflow, CV_GRAY2BGR);
  47             drawOptFlowMap(flow, cflow, 16, 1.5, CV_RGB(0, 255, 0));
  48             cvShowImage("flow", cflow);
  49         }
  50         if(cvWaitKey(30)>=0)
  51             break;
  52         {
  53         CvMat* temp;
  54         CV_SWAP(prevgray, gray, temp);
  55         }
  56     }
  57     cvReleaseCapture(&capture);
  58     return 0;
  59 }