Problem to convert BitmapSource to bitmap using kinect and visual studio 2010

I want to get a frame with Kinect then convert it to bitmap, use emgucv to convert it in grayscale and then convert that in bitmapsource to show in window! I have the code for that but when I run the program there is a case that the video freeze or lag for a moment!I open task manager I can see that program consume a lot of cpu usage in moments!!I want to know if my code is right or there are another way in order to consume less!! I supposed that is the part I convert to bitmap and in grayscale!

  
    byte[] colorData = null;
    WriteableBitmap colorImageBitmap = null;

    void myKinect_ColorFrameReady(object sender, ColorImageFrameReadyEventArgs e)
    {

        using (ColorImageFrame colorFrame = e.OpenColorImageFrame())
        {

            if (colorFrame == null) return;

            if (colorData == null)
                colorData = new byte[colorFrame.PixelDataLength];

            colorFrame.CopyPixelDataTo(colorData);

                if (colorImageBitmap == null)
                {
                    this.colorImageBitmap = new WriteableBitmap(
                        colorFrame.Width,
                        colorFrame.Height,
                        96,  // DpiX
                        96,  // DpiY
                        PixelFormats.Bgr32,
                        null);
                }

                this.colorImageBitmap.WritePixels(
                    new Int32Rect(0, 0, colorFrame.Width, colorFrame.Height),
                    colorData, // video data
                    colorFrame.Width * colorFrame.BytesPerPixel, // stride,
                    0   // offset into the array - start at 0
                    );


                Image<Gray, Byte> My_Image = new Image<Gray, byte>(BitmapFromSource(colorImageBitmap));
                kinectVideo.Source = ToBitmapSource(My_Image);


        }
    }



    private System.Drawing.Bitmap BitmapFromSource(BitmapSource bitmapsource)
    {
        System.Drawing.Bitmap bitmap;
        using (MemoryStream outStream = new MemoryStream())
        {
            BitmapEncoder enc = new BmpBitmapEncoder();
            enc.Frames.Add(BitmapFrame.Create(bitmapsource));
            enc.Save(outStream);
            bitmap = new System.Drawing.Bitmap(outStream);

        }
        return bitmap;

    }

     [DllImport("gdi32")]
    private static extern int DeleteObject(IntPtr o);


     public static BitmapSource ToBitmapSource(IImage image)
    {
        using (System.Drawing.Bitmap source = image.Bitmap)
        {
            IntPtr ptr = source.GetHbitmap(); //obtain the Hbitmap

            BitmapSource bs = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
                ptr,
                IntPtr.Zero,
                Int32Rect.Empty,
                System.Windows.Media.Imaging.BitmapSizeOptions.FromEmptyOptions());

            DeleteObject(ptr); //release the HBitmap
            return bs;
        }
    }

}