[TanaTiX]

Примерно так.

a.filters=[convertiGrigio()];
private function convertiGrigio():BitmapFilter
		{
			var r:Number=0.212671;
			var g:Number=0.715160;
			var b:Number=0.072169;
			return new ColorMatrixFilter
			( 
				[r, g, b, 0, 0,
				r, g, b, 0, 0,
				r, g, b, 0, 0,
				0, 0, 0, 1, 0]
			);
		}