[Insight-developers] Two (big?) problems with itkTIFFImageIO.cxx
Brad King
brad.king at kitware.com
Thu Jul 14 09:51:55 EDT 2005
Zachary Pincus wrote:
> Anyhow, I've tracked the problem down, and it's actually two problems
> at the same time. The first and simplest is that ITK isn't dealing
> properly when certain TIFF tags are missing (though the spec allows
> them to be so). The second is that there's a method called
> TIFFReaderInternal::CanRead() which should be used to check whether the
> TIFF can be properly read; instead it seems to be used to determine
> whether to read the TIFF as RGBA.
>
> These two problems combine so that when a TIFF with a missing tag (e.g.
> in my case 'SamplesPerPixel') is encountered, the default value for the
> tag isn't used, so TIFFReaderInternal::CanRead() returns false. At this
> point, ITK really should just give an error; instead it seems to
> *forcibly* try to read the file as RGBA, which is of course totally the
> wrong way to detect if an image is in fact RGBA.
This patch looks fine to me.
> Someone else really ought to look into the latter issue of why images
> for which TIFFReaderInternal::CanRead() returns false are still read
> in, incorrectly, as RGBA images. I suspect this has to do with calling
> TIFFReadRGBAImage() with the parameter "stopOnError" set to zero, which
> from the man page, appears to disable the ability of this function to
> signal that an image is not an RGBA TIFF by returning zero. Is there a
> *reason* TIFFReadRGBAImage was called in this way?
Please submit this as a bug report:
http://www.itk.org
Thanks,
-Brad
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