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November 1999
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1999.11.02 02:24 "Re: grayscale tiff", by Niles Ritter
emari@medrad3.nac.ac.za wrote: > I have a ccd camera with a software package that saves TIFF images as > grayscale images, but they have 16 Bits Per Sample. (The TIFF6 standard > only allows 4 or 8 bits per sample - so most readers can not read the > images, or convert them to 8 bit images, but then the image contrast is > lost). What is the best solution for this problem? (without losing the > information contained in an image) Probably the best way to maintain the information is to represent high dynamic range with higher spatial resolution. I don't know the best algorithm for doing this, but the idea is to, say, resample the image to higher pixel resolution with a spatial filter until the normalized dynamic range of each new, smaller pixel is closer to effective 8-bits. This has the feel of something that could be done quickly with fast fourier or wavelet transforms. There used to be some graphics algorithm FAQ's around on this, but I don't know where they are these days. --Niles.