Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!think.com!spool.mu.edu!snorkelwacker.mit.edu!bloom-beacon!eru!hagbard!sunic!liuida!isy!lysator.liu.se!zap From: zap@lysator.liu.se (Zap Andersson) Newsgroups: comp.graphics Subject: Re: Color quantization ideas: To histogram or not to histogram, comments? Keywords: graphics quantization Message-ID: <610@lysator.liu.se> Date: 3 May 91 05:56:33 GMT Article-I.D.: lysator.610 References: <606@lysator.liu.se> <10480@labtam.labtam.oz> Sender: news@isy.liu.se (Lord of the News) Distribution: comp Organization: Lysator Computer Club, Linkoping University, Sweden Lines: 45 graeme@labtam.labtam.oz (Graeme Gill) writes: >In article <606@lysator.liu.se>, zap@lysator.liu.se (Zap Andersson) writes: >> I have always, always, always wondered one thing: >> >> * Is there ANY sane reason whatsoever, when trying to quantize a 24 bit > Unfortunately it is difficult to make a computer program see a picture >the way a human sees it. It is only a human judgment that a spaceship on a >background is the most important object in a scene. Not having the ability >to program an "AI" module into a 24 to 8 bit quantizer, it is necessary to Ah, but that was one of my small 'points': The renderer knows, and since it is the renderer doing quantization in my case, things can get nice. (but slow) :-( >fall back on other means of assessing the importance of objects in a scene - >like their relative popularity. Sometimes this produces poor results. Yeah, that is agreed. I'm not interested in ye olde quadliteral 'area of interest'. Someone (hi someone, my mail to you bounced :-( ) suggested render the spaceship with an alpha channel and overlay separately with an intelligen quant software, and I agree totally. But IS there some intelligent overlay-32-bit-images-with-different-criteria-of-importance- while-qiantizing-to-8-bit-code.c source around :-) >statistics on input and in locating the nearest colours on output. I have >written a quantizer that maintains full 24 bit precision throughout, and it >does not add a great deal to the picture quality. No, but 5 vs 6 bits makes a LOT of difference (it's just on the edge of what you see, especially at yucky resolutions, such as PC bleach 320 x 200 that I'm (semi) stuck with :-( ((and must support)) ) > Graeme Gill > Labtam Australia -- * * * * * * * * * * * * * * * * * (This rent for space) * My signature is smaller than * Be warned! The letter 'Z' is Copyright 1991 * yours! - zap@lysator.liu.se * by Zap Inc. So are the colors Red, Green and * * * * * * * * * * * * * * * * * Greenish-yellow (Blue was taken by IBM)