2008.04.16 22:45 "[Tiff] Floating Point Tiff Format?", by Fred Weinhaus

2008.04.16 23:13 "Re: [Tiff] Floating Point Tiff Format?", by Frank Warmerdam

I am new to this list.

I was wondering if libtiff supports floating point format tiff? I am interested in both floating point grayscale images and floating point RGB images?

If there is support for this, how does one go about enabling it - does anything special need to be done in the configure/build for libtiff?

Is there some documentation for the floating point format and if so where might I find that. I see nothing about floating point format in the TIFF 6.0 Specs.

I also saw an old post about the potential for a complex (real and imaginary) tiff format? Did anything come from that.

My questions relate to the use of a floating point or complex format for generating FFT of images using the FFTW package and storing the results in a relevant TIFF format.


libtiff supports floating point files by default; however, I don't think it includes any default visual interpretation of floating point images. So the "read as RGBA" interfaces likely fail for floating point images.

In any event, I use libtiff often to read and write floating point tiff files without any problems. This is via the TIFFReadEncodedStrip/Tile functions.

There is also support in libtiff for reading and writing complex floating point values, but this is ideosyncratic to libtiff, and not part of the TIFF specification. I extended libtiff with the sample formats:

#define     SAMPLEFORMAT_COMPLEXINT     5       /* !complex signed int */
#define     SAMPLEFORMAT_COMPLEXIEEEFP  6       /* !complex ieee floating */

To the best of my knowledge there are few applications that support these types, though my GDAL library does.

Best regards,

I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam@pobox.com
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