November 18th, 2006


HDR and Linux

Anybody here do any HDR work with Linux?

I think I'm finally wrapping my head around all the concepts, formats, tools, processes, etc, but I've yet to do anything with any of it. Although I have some source images I'm eager to play with.

If my understanding is correct, there are basically two phases:

1) get multiple source images (on a tripod) of different exposures (shutter speed differences, not aperature) and run them through a tool to convert them into an HDR file (floating point pixel values, not 8-bit per channel). These file formats are either *.hdr or the ILM OpenEXR format? Or maybe some other formats. The tool mkhdr looks like it can do this, with some hand-holding. (you have to give it ppm files and shutter speeds on command line, since it can't read any raw files, but that's understandable because there's a dozen+ raw formats...)

2) given HDR file of some format (depending on tool), do cool shit with it. Canonical examples are various blurs that used to clip out highs, and "tone mapping", of which there are various algorithms it seems to reduce the HDR data down into something sexy for screen (which is low dynamic range)

So I guess my questions are:

-- best Linux tool for creating HDR images? is mkhdr good? I can automate the parameter hell.
-- best tools for converting between *.hdr and OpenEXR, etc? The imagemagick of HDR file formats?
-- best tone mapping algorithms to create the typical HDR photos you see online

Any pointers appreciated. Thanks!