mike@relgyro.stanford.edu (Mike Macgirvin) (02/03/89)
Since we don't have a color machine available to us, I have been converting a lot of Sun color images to our monochrome systems, using a variety of programs. I have found that most of the conversion programs available use several different dithering techniques, but almost always the resulting image has a very 'grainy' look to it. I have found that for most 8 bit deep images, dithering is unacceptable. Instead, I start with an 8 bit greyscale image (converting from color if necessary), get 8 bytes from input, and for each, if > 127, then I set the corresponding bit of an output byte. This results in a very sharp monochrome image. Admittedly, a lot of shades are lost, but isn't that what's supposed to happen when you compress color to mono? I just bring this up for folks who are writing conversion programs. Dithering is almost taken for granted as 'the ONE TRUE CONVERSION'. Don't overlook simpler methods that may achieve better results. /* ************************************************************************ m m k Mike Macgirvin m m m m o k k eee Stanford Relativity Gyro Experiment m m m k k e e Stanford University m m i kk eeeee (415) 725-4117 m m i k k e ARPA: mike@relgyro.stanford.edu (36.64.0.50) m m i k k eeee UUCP: /dev/null This room has been punched out. Now where are all the gazingas? ************************************************************************* */