samples/c/fback_c.c

   1 #include "opencv2/video/tracking.hpp"
   2 #include "opencv2/highgui/highgui.hpp"
   3 #include <stdio.h>
   4 void help()
   5 {
   6         printf(
   7             "\n This program demonstrate dense \"Farneback\n optical flow\n"
   8                         "It read from camera 0, and shows how to use and display dense Franeback optical flow\n"
   9             "Usage: \n"
  10             "./fback_c \n");
  11
  12 }
  13 void drawOptFlowMap(const CvMat* flow, CvMat* cflowmap, int step,
  14                     double scale, CvScalar color)
  15 {
  16     int x, y;
  17     for( y = 0; y < cflowmap->rows; y += step)
  18         for( x = 0; x < cflowmap->cols; x += step)
  19         {
  20             CvPoint2D32f fxy = CV_MAT_ELEM(*flow, CvPoint2D32f, y, x);
  21             cvLine(cflowmap, cvPoint(x,y), cvPoint(cvRound(x+fxy.x), cvRound(y+fxy.y)),
  22                  color, 1, 8, 0);
  23             cvCircle(cflowmap, cvPoint(x,y), 2, color, -1, 8, 0);
  24         }
  25 }
  26
  27 int main(int argc, char** argv)
  28 {
  29     CvCapture* capture = cvCreateCameraCapture(0);
  30     CvMat* prevgray = 0, *gray = 0, *flow = 0, *cflow = 0;
  31
  32     help();
  33
  34     if( !capture )
  35         return -1;
  36
  37     cvNamedWindow("flow", 1);
  38
  39     for(;;)
  40     {
  41         int firstFrame = gray == 0;
  42         IplImage* frame = cvQueryFrame(capture);
  43         if(!frame)
  44             break;
  45         if(!gray)
  46         {
  47             gray = cvCreateMat(frame->height, frame->width, CV_8UC1);
  48             prevgray = cvCreateMat(gray->rows, gray->cols, gray->type);
  49             flow = cvCreateMat(gray->rows, gray->cols, CV_32FC2);
  50             cflow = cvCreateMat(gray->rows, gray->cols, CV_8UC3);
  51         }
  52         cvCvtColor(frame, gray, CV_BGR2GRAY);
  53
  54         if( !firstFrame )
  55         {
  56             cvCalcOpticalFlowFarneback(prevgray, gray, flow, 0.5, 3, 15, 3, 5, 1.2, 0);
  57             cvCvtColor(prevgray, cflow, CV_GRAY2BGR);
  58             drawOptFlowMap(flow, cflow, 16, 1.5, CV_RGB(0, 255, 0));
  59             cvShowImage("flow", cflow);
  60         }
  61         if(cvWaitKey(30)>=0)
  62             break;
  63         {
  64         CvMat* temp;
  65         CV_SWAP(prevgray, gray, temp);
  66         }
  67     }
  68     cvReleaseCapture(&capture);
  69     return 0;
  70 }