Loading images from a Camera or Video

If you would like to do real time video processing you can even integrate your cameras into OpenCV.

It is easy to load an image from a camera. Ensure that camera is properly connected and detected by your computer.

CvCapture* capture = cvCaptureFromCAM(0); // capture from video device #0
CvCapture* capture = cvCaptureFromAVI("infile.avi");

Incase there is only one camera, or to select any camera from multiple connecterd cameras, 0 can be replaced with -1.

The camera link is stored in the capture structure.

Alternatively, frames can also be processed from a video :

CvCapture* capture = cvCaptureFromAVI("filename.avi");


Retreiving the image frame from the link:

IplImage* img = 0; // Declare a new image pointer

if(!cvGrabFrame(capture)){ // capture a frame
printf("Could not grab a frame\n\7");
exit(0);
}

img=cvRetrieveFrame(capture); // retrieve the captured frame


Important Caution :

One must release the image source after using it ->

cvReleaseCapture(&capture); // releases the capture link