How to avoid the OpenCV out of memory exception?

asked 2015-03-28 13:13:05 -0500

updated 2015-03-28 14:15:35 -0500

berak gravatar image

I am using OpenCvSharp and this code to get the position of a user's eyes.

CvCapture cap = CvCapture.FromCamera(CaptureDevice.Any);
using (CvWindow w = new CvWindow("Eye Tracker"))
{

    while (CvWindow.WaitKey(10) < 0 && beginn) //beginn)
    {
        using (IplImage img = cap.QueryFrame())
        using (IplImage smallImg = new IplImage(new CvSize(Cv.Round(img.Width / Scale), Cv.Round(img.Height / Scale)), BitDepth.U8, 1))
        {

            using (IplImage gray = new IplImage(img.Size, BitDepth.U8, 1))
            {
                Cv.CvtColor(img, gray, ColorConversion.BgrToGray);
                Cv.Resize(gray, smallImg, Interpolation.Linear);
                Cv.EqualizeHist(smallImg, smallImg);
            }

            using (CvHaarClassifierCascade cascade = CvHaarClassifierCascade.FromFile(@"D:\haarcascade_eye.xml"))
            using (CvMemStorage storage = new CvMemStorage())
            {
                storage.Clear();
                CvSeq<CvAvgComp> eyes = Cv.HaarDetectObjects(smallImg, cascade, storage, ScaleFactor, MinNeighbors, 0, new CvSize(30, 30));
                if (eyes.Total == 2)
                {

                    // do something
                }
                w.Image = img;
            }
        }
    }
}

It works, but the program gets bigger and bigger in memory till it finally says that it doesn't have enough and points at

CvSeq<CvAvgComp> eyes = Cv.HaarDetectObjects(smallImg, cascade, storage, ScaleFactor, MinNeighbors, 0, new CvSize(30, 30));

How to solve this out of memory exception?

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Comments

1

I'm not familiar with OpenCVSharp. But normally the IplImage structure is outdated and replaced by the Mat structure (IplImage is OpenCV 1 structure).

If the Mat structure exists in OpenCVSharp I highly recommend you to use it. With the IplImage structure you have to free the memory manually. I think your IplImage img, IplImage smallImg and IplImage gray will be allocated each loop continous new, but is not freed after use.

matman gravatar imagematman ( 2015-03-28 15:00:11 -0500 )edit
1

also please do not re-load the haar-cascade for each frame processed, but only once (on startup of your prog)

berak gravatar imageberak ( 2015-03-28 15:14:30 -0500 )edit

@matman How do you use the Mat structure? I tried CvMat img = cap.QueryFrame();

PeterWeter gravatar imagePeterWeter ( 2015-03-28 16:20:40 -0500 )edit

@berak That solved it. Great!

PeterWeter gravatar imagePeterWeter ( 2015-03-28 16:20:52 -0500 )edit

@PeterWeter, again, like matman said before, - also prefer the Mat interfaces instead of the outdated IplImage ones.

berak gravatar imageberak ( 2015-03-28 16:27:14 -0500 )edit
2

In C++ it is not CvMat, but cv::Mat. Cv"Something" suggests that it is still the old C structure.

matman gravatar imagematman ( 2015-03-28 16:34:38 -0500 )edit