OpenCV - Webcam does not work

Question

I'm learning OpenCV because I want to build and program a 3D Scanner over the summer.

I bought three webcams for this purpose (two for the actual stereo images and one for texture [or as a backup]).

I tried to get a webcam's video with OpenCV. However, this does not work, as I ended up with a black screen, instead of video.

I then tried the same code with my grandmother's webcam. It worked fine. However, I already bought 3 webcams of the type that I was planning on using to build my scanner: http://www.amazon.com/Webcam-Camera-Vision-Meeting-compatible/dp/B0015TJNEY/ref=pd_bxgy_e_img_b

I don't want to buy any new webcams.

Does anybody have any idea of why my webcams don't work with OpenCV (they work with other programs)?

How can I get OpenCV to accept my webcams?

Any suggestions would be appreciated!

Thanks

@shobhit Well, I looked for any error messages - none. I also looked at the driver file. It's called: usbvideo.sys. I also looked around Stackoverflow and found: stackoverflow.com/questions/4430367/…. It basically states my problem. But the first solution doesn't work because I had already included the cvWaitKey. The second solution seems to be my problem, but I want to know how to fix it. — eboix
What is your operating system? We can tell it is windows by the usbvideo.sys driver file but even so. Is the camera working with other programs? — Rui Marques
The camera works with other programs, such as VLC player. I have Windows 7 Enterprise. If I can't get my webcam to work with OpenCV, then I'll download some other library and get the webcam input into a file, which I will then read with OpenCV. — eboix

Mark Mark · Accepted Answer · 2012-06-16T19:09:59

If your program pass this step , you should try a different number for cvCaptureFromCAM(0); 0 is the first web cam but maybe your's is set as 1, 2 or 3. you can also try -1 and see what happens

CvCapture *capture;
capture = cvCaptureFromCAM(0);
if (!capture)
{
    printf("Error at capture");
    return 1;
}

OpenCV - Webcam does not work

1 Answers