private void PreprocessInputImage( BitmapData data, int width, int height, _
  byte[] buf )
		{
			int stride = data.Stride;
			int offset = stride - width * 3;
			int len = (int)( ( width - 1 ) / 8 ) + 1;
			int rem = ( ( width - 1 ) % 8 ) + 1;
			int[] tmp = new int[len];
			int i, j, t1, t2, k = 0;
 
			unsafe
			{
				byte * src = (byte *) data.Scan0.ToPointer( );
 
				for ( int y = 0; y < height; )
				{
					// collect pixels
					Array.Clear( tmp, 0, len );
 
					// calculate
					for ( i = 0; ( i < 8 ) && ( y < height ); i++, y++ )
					{
						// for each pixel
						for ( int x = 0; x < width; x++, src += 3 )
						{
							// grayscale value using BT709
							tmp[(int) ( x / 8 )] += (int)( 0.2125f * src[RGB.R] + 0.7154f * _
  src[RGB.G] + 0.0721f * src[RGB.B] );
						}
						src += offset;
					}
 
					// get average values
					t1 = i * 8;
					t2 = i * rem;
 
					for ( j = 0; j < len - 1; j++, k++ )
						buf[k] = (byte)( tmp[j] / t1 );
					buf[k++] = (byte)( tmp[j] / t2 );
				}
			}
		}

Private Sub PostprocessInputImage(data As BitmapData, width As Integer, height _
  As Integer, buf As Byte())
        Dim stride As Integer = data.Stride
        Dim offset As Integer = stride - width * 3
        Dim len As Integer = CInt((width - 1) / 8) + 1
        Dim lenWM1 As Integer = len - 1
        Dim lenHM1 As Integer = CInt((height - 1) / 8)
        Dim [rem] As Integer = ((width - 1) Mod 8) + 1
 
        Dim i As Integer, j As Integer, k As Integer
 
        'Das Array für die Pixel-Bytes der Bitmap erstellen
        Dim bytes(stride * height * 1) As Byte
        'Kopieren der Bild-Pixel in das Array 
        System.Runtime.InteropServices.Marshal.Copy(data.Scan0, bytes, 0, _
          bytes.Length)
        Dim scr As Integer = -1
 
        ' for each line
        For y As Integer = 0 To height - 1
            i = (y / 8)
 
            ' for each pixel
            Dim x As Integer = 0
            While x < width
                j = x / 8
                k = i * len + j
 
                ' check if we need to highlight moving object
                If buf(k) = 255 Then
                    ' check for border
                    If ((x Mod 8 = 0) AndAlso ((j = 0) OrElse (buf(k - 1) = _
                      0))) OrElse ((x Mod 8 = 7) AndAlso ((j = lenWM1) OrElse ( _
                      buf(k + 1) = 0))) OrElse ((y Mod 8 = 0) AndAlso ((i = 0) _
                      OrElse (buf(k - len) = 0))) OrElse ((y Mod 8 = 7) AndAlso _
                      ((i = lenHM1) OrElse (buf(k + len) = 0))) Then
                        src(RGB.R) = 255
                    End If
                End If
                x += 1
                src += 3
            End While
            src += offset
        Next
    End Sub