private Bitmap ProcessSingleImage(Bitmap _src)
        {
            // Apply filter.
            Bitmap tmp = new DifferenceEdgeDetector().Apply(Grayscale.CommonAlgorithms.BT709.Apply(_src));

            _src.Dispose();

            // Back to 24bpp.
            Bitmap tmp2 = new GrayscaleToRGB().Apply(tmp);

            tmp.Dispose();

            return(tmp2);
        }
        private Bitmap ProcessSingleImage(Bitmap _src)
        {
            // Apply filter.
            Bitmap img = (_src.PixelFormat == PixelFormat.Format24bppRgb) ? _src : CloneTo24bpp(_src);
            Bitmap tmp = new DifferenceEdgeDetector().Apply(Grayscale.CommonAlgorithms.BT709.Apply(img));

            _src.Dispose();
            if (_src.PixelFormat != PixelFormat.Format24bppRgb)
            {
                img.Dispose();
            }

            // Back to 24bpp.
            Bitmap tmp2 = new GrayscaleToRGB().Apply(tmp);

            tmp.Dispose();

            return(tmp2);
        }