samples/c/fback_c.c

   1 #include "opencv2/video/tracking_c.h"
   2 #include "opencv2/highgui/highgui_c.h"
   3 #include "opencv2/imgproc/imgproc_c.h"
   4 #include <stdio.h>
   5
   6 static void help(void)
   7 {
   8     printf(
   9             "\n This program demonstrate dense \"Farneback\n optical flow\n"
  10             "It read from camera 0, and shows how to use and display dense Franeback optical flow\n"
  11             "Usage: \n"
  12             "./fback_c \n");
  13
  14 }
  15
  16 static void drawOptFlowMap(const CvMat* flow, CvMat* cflowmap, int step,
  17                     double scale, CvScalar color)
  18 {
  19     int x, y;
  20     (void)scale;
  21     for( y = 0; y < cflowmap->rows; y += step)
  22         for( x = 0; x < cflowmap->cols; x += step)
  23         {
  24             CvPoint2D32f fxy = CV_MAT_ELEM(*flow, CvPoint2D32f, y, x);
  25             cvLine(cflowmap, cvPoint(x,y), cvPoint(cvRound(x+fxy.x), cvRound(y+fxy.y)),
  26                  color, 1, 8, 0);
  27             cvCircle(cflowmap, cvPoint(x,y), 2, color, -1, 8, 0);
  28         }
  29 }
  30
  31 int main( int argc, char** argv )
  32 {
  33     CvCapture* capture = cvCreateCameraCapture(0);
  34     CvMat* prevgray = 0, *gray = 0, *flow = 0, *cflow = 0;
  35     (void)argc; (void)argv;
  36
  37     help();
  38
  39     if( !capture )
  40         return -1;
  41
  42     cvNamedWindow("flow", 1);
  43
  44     for(;;)
  45     {
  46         int firstFrame = gray == 0;
  47         IplImage* frame = cvQueryFrame(capture);
  48         if(!frame)
  49             break;
  50         if(!gray)
  51         {
  52             gray = cvCreateMat(frame->height, frame->width, CV_8UC1);
  53             prevgray = cvCreateMat(gray->rows, gray->cols, gray->type);
  54             flow = cvCreateMat(gray->rows, gray->cols, CV_32FC2);
  55             cflow = cvCreateMat(gray->rows, gray->cols, CV_8UC3);
  56         }
  57         cvCvtColor(frame, gray, CV_BGR2GRAY);
  58
  59         if( !firstFrame )
  60         {
  61             cvCalcOpticalFlowFarneback(prevgray, gray, flow, 0.5, 3, 15, 3, 5, 1.2, 0);
  62             cvCvtColor(prevgray, cflow, CV_GRAY2BGR);
  63             drawOptFlowMap(flow, cflow, 16, 1.5, CV_RGB(0, 255, 0));
  64             cvShowImage("flow", cflow);
  65         }
  66         if(cvWaitKey(30)>=0)
  67             break;
  68         {
  69         CvMat* temp;
  70         CV_SWAP(prevgray, gray, temp);
  71         }
  72     }
  73     cvReleaseCapture(&capture);
  74     return 0;
  75 }