AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

1999.11.01 12:42 "grayscale tiff", by Em Latti
1999.11.02 02:24 "Re: grayscale tiff", by Niles Ritter
1999.11.02 10:35 "Re: grayscale tiff", by Ivo Penzar

1999.11.02 02:24 "Re: grayscale tiff", by Niles Ritter

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.