[Insight-developers] [Fwd: Changes to MetaImage...]

[Stephen R. Aylward]

The only difficulty is that PNG doesn't provide element spacing
information.   How about a medical format - e.g., analyze?

Stephen

"Daniel J. Blezek, Ph.D." wrote:
> 
> Stephen and Parag,
> 
>   This exact issue drove the discussion about file reading and writing at
> last week's telephone conference.  I have several ideas in mind as to
> finding images and writing images for regression testing, but have not
> made them happen just yet.  In the mean time, I would welcome any
> suggestions you may have as to how to address this issue.  In our
> experience with VTK, which may be different for ITK, some platforms
> require a platform specific "gold image", and require special processing.
> 
> Here are some of my ideas, strictly related to regression testing:
> 
> -  Have a Toolkit similar to Java, so to get the name of a file you would
> do something like this:
> 
>     std::string s = Toolkit::GetFileName ( "VHF/Head.png" );
> 
>     The Toolkit would properly expand the file name to be the path to the
> image you want, allowing images to be stored on fixed media(CDROM).  On
> the outbound side, you would request an output image in a similar manner:
> 
>     std::string s = Toolkit::GetImageTestResultFileName (
> "itkFileIOMetaImageTest" );
> 
>     The Toolkit would expand this name to a directory where test images
> sit, and a latter process would pick up the images and compare them to the
> "gold standard".  If the test were run in an example mode, it would simply
> write the output in the current directory, for the user to take a look at
> later.
> 
> - This raises the issue of file formats yet again.  Everyone seems to cook
> up their own file format to meet the needs of whatever problem they have
> at hand! (We are no exception...)  In my view, the current problem at hand
> is regression testing.  I've given this issue some thought.  We need:
> 
>   - a file format that is easily displayed locally and through a browser
>   - a format that is easily created by all Insight developers
>   - a format that has 2D support at minimum
>   - a format that supports as many common datatypes as possible
> 
> The first point drives the selection down considerably.  The only real
> canidates are Gif, Jpeg, and PNG.  Gif and Jpeg are generally lossy
> compression, and don't fit the bill.  PNG is a relatively new format, with
> good support from most OS/viewers/browsers.  PNG is also licensed for use
> in a toolkit such as ITK.  The real downside is that PNG only supports 8
> and 16 bit datatypes.  I feel this is acceptable because medical image
> data generally comes in these two types, so that should not be a limiting
> factor.  PNG support is built and working on my local checkout.
> 
> Since I'm doing most of the testing infrastructure, I will offer to serve
> as the focal point for this issue, and welcome any suggestions.
> 
> Thanks,
> -dan
> 
> On Thu, 22 Mar 2001, Stephen R. Aylward wrote:
> 
> >
> > How should we reference data files in the example directories if the
> > build is placing the executables in different directories?  See below
> > for more details....
> >
> > Thanks,
> > Stephen
> >
> > Parag Chandra wrote:
> > >
> > > Ok, that solves half the problem. I'll put the test and the accompanying
> > > files into examples. But how would I reference that (the examples) directory from within
> > > the test program? Each platform will place the executable for this test into
> > > something like ${CMAKE_BINARY_DIR}/Examples, but ${CMAKE_BINARY_DIR} isn't
> > > even an environment variable for me to reference, it's a variable that's
> > > internal to CMake. If I reference the file without the pathname, like
> > > "TestInput.mhd", then the file has to be in the same directory as the
> > > executable, and that means I would have to place a copy of the test file
> > > into Insight-Cygwin, Insight-VC++, Insight-Linux, etc. Not only is that
> > > redundant, but there's no way I could foresee the additional platforms we
> > > might target, and so the test running on those platforms will generate an
> > > exception when it can't find the file. The only thing I can see is to place
> > > the test file into one directory, and then run the test for each platform
> > > from that directory by using the full pathname of the executable, e.g.
> > > /Insight-Cygwin/Examples/itkFileIOMetaImageTest.exe. Does anyone have any
> > > other ideas?
> > >
> > > Thanks,
> > > -Parag
> > >
> > > ---
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> >
> > --
> > ===============================================
> > Stephen R. Aylward
> > Assistant Professor of Radiology
> > Adjunct Assistant Professor of Computer Science
> > http://www.cs.unc.edu/~aylward
> > aylward@unc.edu
> > (919) 966-9695
> >
> > _______________________________________________
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> >
> 
> --
> Daniel Blezek, Ph.D.
> blezek@crd.ge.com
> Visualization and Computer Vision Program
> Electronic Systems Lab
> GE Corporate Research & Development

-- 
===============================================
Stephen R. Aylward
Assistant Professor of Radiology
Adjunct Assistant Professor of Computer Science
http://www.cs.unc.edu/~aylward
aylward@unc.edu
(919) 966-9695