[Insight-developers] Extending the Analyze Reader to read/write RGB files?

kent williams norman-k-williams at uiowa.edu
Tue Apr 21 14:12:59 EDT 2009


Thanks to Luis, I guess I'm supposed to get the itk::AnalyzeImageIO to
support RGB analyze files.

Unfortunately, I can't find any place that describes the data layout of
Analyze 7.5 RGB files.  The NIfTI reader seems to assume that each 24-bit
RGB pixel is contiguous in memory.

The Analyze 7.5 reader has a bunch of stuff from the original BRAINS2
Analyze file reader, which is commented out, and it suggess that RGB files
are written out as an R volume followed by a G volume followed by a B
volume.  Now, the code that's commented out, when I look at it, seems really
wrong and old -- old enough and wrong enough that I don't trust its
assumptions.

But that commented-out code raises my doubts about what the true Analyze 7.5
RGB data layout is.  And Google search turns up one sketchy PDF file about
the 7.5 format that doesn't explain RGB image format, and the actual Analyze
7.5 header is no more informative.

Does anyone know what the answer is, and does anyone have examples of that
rara avis, an RGB Analyze7.5 file?

And is there an application that can READ an RGB Analyze 7.5 file? The
original bug report complained about not being able to WRITE such an image
file, and makes no mention of being able to read one.

Now, if a developer is writing files out to be read in with any modern
application, Analyze files are a poor choice -- in this case, I'd suggest
using a NIfTI file instead.  If they're using an old program that claims to
be able to read RGB Analyze files, I can understand.

And a further mystery -- who is x25c54?



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