private static ByteImage ToChannelImage(this BitmapSource src, int offset)
{
if (src.Format == PixelFormats.BlackWhite ||
src.Format == PixelFormats.Gray2 ||
src.Format == PixelFormats.Gray4 ||
src.Format == PixelFormats.Gray8 ||
src.Format == PixelFormats.Gray16 ||
src.Format == PixelFormats.Gray32Float)
{
return(src.ToIntensityImage());
}
var bmp = src.AsBgr24();
var data = new byte[bmp.PixelWidth * bmp.PixelHeight * 3];
bmp.CopyPixels(data, bmp.PixelWidth * 3, 0);
var r = new ByteImage(bmp.PixelWidth, bmp.PixelHeight);
for (var dy = 0; dy < r.Height; dy++)
{
for (var dx = 0; dx < r.Width; dx++)
{
r[dx, dy] = data[(dx + dy * r.Width) * 3 + offset];
}
}
return(r);
}
/// <summary>
/// Returns a gray scale image that contains the luminance defined in MPEG of the specified image.
/// </summary>
/// <param name="source">A <see cref="BitmapSource"/> to compute luminance.</param>
/// <returns>The new <see cref="ByteImage"/>.</returns>
public static ByteImage ToLuminanceImage(this BitmapSource source)
{
var bmp = source.AsBgr24();
var data = new byte[bmp.PixelWidth * bmp.PixelHeight * 3];
bmp.CopyPixels(data, bmp.PixelWidth * 3, 0);
var r = new ByteImage(bmp.PixelWidth, bmp.PixelHeight);
var yc = new Vector3(66, 129, 25);
var i = 0;
for (var dy = 0; dy < r.Height; dy++)
{
for (var dx = 0; dx < r.Width; dx++)
{
Vector3 sv;
sv.Z = data[i++];
sv.Y = data[i++];
sv.X = data[i++];
r[dx, dy] = (byte)(((int)(Vector3.Dot(yc, sv) + 128) >> 8) + 16);
}
}
return(r);
}
