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TIFF and LibTiff Mail List Archive

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2010.05.08 18:39 "[Tiff] Merge several TIFFG4 images", by Oliver Geisen
2010.05.10 11:40 "Re: [Tiff] Tiff Digest, Vol 72, Issue 4", by Weichao Wang
2010.05.10 04:04 "[Tiff] Merging multiple Group4 compressed TIFF files", by Richard Nolde
2010.06.22 19:29 "Re: [Tiff] Tiff Digest, Vol 73, Issue 14", by Morgenstern, James

2010.06.22 19:29 "Re: [Tiff] Tiff Digest, Vol 73, Issue 14", by Morgenstern, James

Slow down -- you are confusing two different concepts: number of channels and number of bits per channel.

If you have 3 channels of 8 bit data then using the RGB function to read and display using 3 color mapping.

But if you have 1 channel of 32 bit data [I assume this is integer and not float?] then you need a display device that is capable of 2^32 different gray levels OR you need to transform the data to map the 32 bits down to say 8 bits. [or 16 bits]. So read a line of data and then transform each data entry: dataout[i] = (data[i] + offset) / gain;

To restate: your problem is to match the dynamic range of the display device to the dynamic range of the data. Can you histogram the data to get a sense of what offset and gain you should use?

-----Original Message-----

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Sent: Tuesday, June 22, 2010 1:00 PM

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Subject: Tiff Digest, Vol 73, Issue 14

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