[Insight-developers] failing itkImageFileReaderDimensionsTest_MHD

[Bradley Lowekamp]

Are there any other valid cases I am not considering here?


On May 18, 2009, at 2:38 PM, Lowekamp, Bradley (NIH/NLM/LHC) [C] wrote:

> There are bugs in the ImageFileReader related to reading of images  
> where dimensions don't match. It can be broken into the following  
> cases:
>
>
> 1) IO Dimension (from file) == ImageDimension (tempted image type)
>
> This works good, it's the normal things to do.
>
> 2) IO Dimension < ImageDimension
>
> ImageSeriesReader makes use of this. When reading 2D slices into a  
> 3D image it requests ImageFileReader regions with size [x, y, 1].  
> And ImageFileReader::GenerateOutputInformation pads the size of the  
> output image's LargestPossibleRegion with 1s. This works too, I  
> don't see any problems. (Excluding direction cosine issues)
>
> 3) IO Dimension > ImageDimension
>
> 3a) If the IORegion's size is padded with 1s after ImageDimension,  
> then currently should work with all file types. For example if a 3D  
> image file has size [x,y,1] then it can be read into a 2D image with  
> size [x,y]
>
>
> 3b) If the IORegions's size ends in non-one values, we can have  
> problems, like segfaults. This is because the size of the buffers  
> don't match, and ImageIO object will over write the image buffer.
> However the ImageIO classes which support streaming appear to handle  
> this case correctly, by padding the region size with 1s.
>
>
> My proposed solution is to modify  
> ImageIOBase::GenerateStreamableReadRegionFromRequestedRegion to  
> actually return the full dimensionality of the image. This reflects  
> what the ImageIO can actually do. Then in  
> ImageFileReader::EnlargeOutputRequestedRegion and a check to make  
> sure this case is not occurring.
>
>
>
>
> On May 16, 2009, at 3:39 PM, Lowekamp, Bradley (NIH/NLM/LHC) [C]  
> wrote:
>
>> This is my doing, I should be checking the fix in on monday.
>>
>> http://www.cdash.org/CDash/testSummary.php?project=2&name=itkImageFileReaderDimensionsTest_MHD&date=2009-05-16
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> ========================================================
> Bradley Lowekamp
> Lockheed Martin Contractor for
> Office of High Performance Computing and Communications
> National Library of Medicine
> blowekamp at mail.nih.gov
>
>
> <ATT00001.txt>

========================================================
Bradley Lowekamp
Lockheed Martin Contractor for
Office of High Performance Computing and Communications
National Library of Medicine
blowekamp at mail.nih.gov


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