A graphics system for use with a computer in a gray-scale mode. The graphics system utilizes a lookup table having index values to be stored in a frame buffer. The lookup table is addressed by converting color information such as RGB color information, to a luminance value, which is then used to access...http://www.google.com/patents/US5546105?utm_source=gb-gplus-sharePatent US5546105 - Graphic system for displaying images in gray-scale
