OpenCV:Getting Started

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On Linux

On Fedora11 you will want the following packages

  • opencv
  • opencv-devel
  • opencv-python

You can install those with:

yum install opencv opencv-devel opencv-python

Here is a sample C program:

#include <opencv/cv.h>
#include <opencv/highgui.h>
#include <stdio.h>

// A Simple Camera Capture Framework
int main() {

  CvCapture* capture = cvCaptureFromCAM( CV_CAP_ANY );
  if( !capture ) {
    fprintf( stderr, "ERROR: capture is NULL \n" );
    return -1;

  // Create a window in which the captured images will be presented
  cvNamedWindow( "mywindow", CV_WINDOW_AUTOSIZE );

  // Show the image captured from the camera in the window and repeat
  while( 1 ) {
    // Get one frame
    IplImage* frame = cvQueryFrame( capture );
    if( !frame ) {
      fprintf( stderr, "ERROR: frame is null...\n" );

    cvShowImage( "mywindow", frame );
    // Do not release the frame!

    //If ESC key pressed, Key=0x10001B under OpenCV 0.9.7(linux version),
    //remove higher bits using AND operator
    if( (cvWaitKey(10) & 255) == 27 ) break;

  // Release the capture device housekeeping
  cvReleaseCapture( &capture );
  cvDestroyWindow( "mywindow" );
  return 0;

You can compile it with:

gcc sample.c -o sample -lcv -lhighgui

You can then run the code with: