CODEWITHSUNDEEP
opencv
John
John

Reputation:

Why does OpenCV give me a black screen?

I'm currently trying to use OpenCV (using the Processing library). However, when I try to run any examples (either the Processing ones or the C ones included with OpenCV), I see nothing but black instead of input from the camera. The camera's LED indicator does turn on.. has anyone had the same problem? is my camera somehow incompatible with openCV? It's an Acer Crystal Eye...

Thanks,

Upvotes: 10

Views: 11236

Answers (4)

Phil Hannent
Phil Hannent

Reputation: 12317

I recently had the same problem. The OpenCV library on its own just gave me a blank screen, I had to include the videoInput library:

http://muonics.net/school/spring05/videoInput/

An example I followed was:

#include "stdafx.h"
#include "videoInput.h"
#include "cv.h"
#include "highgui.h"

int main()
{
    videoInput VI;
    int numDevices = VI.listDevices();
    int device1= 0;
    VI.setupDevice(device1);
    int width = VI.getWidth(device1);
    int height = VI.getHeight(device1);
    IplImage* image= cvCreateImage(cvSize(width, height), 8, 3);
    unsigned char* yourBuffer = new unsigned char[VI.getSize(device1)];
    cvNamedWindow("test");
    while(1)
    {
        VI.getPixels(device1, yourBuffer, false, false);
        image->imageData = (char*)yourBuffer;
        cvConvertImage(image, image, CV_CVTIMG_FLIP);
        cvShowImage("test", image);
        if(cvWaitKey(15)==27) break;
    }

    VI.stopDevice(device1);
    cvDestroyWindow("test");
    cvReleaseImage(&image);

    return 0;
}

From this source: http://www.aishack.in/2010/03/capturing-images-with-directx/

Upvotes: 1

Nick Banks
Nick Banks

Reputation: 4408

OpenCV only supports a limited number of types of cameras. Most likely your camera is not supported. You can look at either the source code or their web site to see which are supported.

Upvotes: 0

karlphillip
karlphillip

Reputation: 93410

OpenCV 2.1 still has a few problems with 64bits OS. You can read this topic on the subject.

If you're looking for working/compilable source code that shows how to use the webcam, check this out.

Let us know if it helped you.

Upvotes: 4

Atilla Filiz
Atilla Filiz

Reputation: 2432

I had somewhat same problem on Ubuntu. I downloaded a code from here: http://www.rainsoft.de/projects/pwc.html It does an extra step before starting to get frames(i think setting FPS). Worth a try, the code is easy to read and works with non-philips cams.

Upvotes: 0

Related Questions