FrameProcessor.GetBackproject C# (CSharp) Method

    private Image<Gray, Byte> GetBackproject(Image<Gray, Byte> hue, DenseHistogram _hist,Image<Gray,Byte> mask,Rectangle hide)
    {
        Image<Gray, Byte> backproject = new Image<Gray, byte>(hue.Width, hue.Height);
        var imgs = new IntPtr[1] { hue };
        Emgu.CV.CvInvoke.cvCalcBackProject(imgs, backproject, _hist);
        Emgu.CV.CvInvoke.cvAnd(backproject, mask, backproject, IntPtr.Zero);

        if (th_check)
        {
            backproject.ROI = face_rect;
            if (backproject.GetAverage().Intensity < backproj_threshold/2)
            {
                isTracked = false;
            }
            th_check = false;
            Emgu.CV.CvInvoke.cvResetImageROI(backproject);
        }

        hide.Height += 50;
        Emgu.CV.CvInvoke.cvSetImageROI(backproject, hide);
        try
        {
            Emgu.CV.CvInvoke.cvZero(backproject);
        }
        catch { }
        Emgu.CV.CvInvoke.cvResetImageROI(backproject);

        return backproject;
    }