public NiblackThreshold()
{
formatTranslations = new Dictionary<PixelFormat, PixelFormat>();
formatTranslations[PixelFormat.Format8bppIndexed] = PixelFormat.Format8bppIndexed;
formatTranslations[PixelFormat.Format24bppRgb] = PixelFormat.Format24bppRgb;
formatTranslations[PixelFormat.Format32bppRgb] = PixelFormat.Format32bppRgb;
formatTranslations[PixelFormat.Format32bppArgb] = PixelFormat.Format32bppArgb;
}