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ERROR dicom.ReadElement: Undefined length disallowed #82

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IChocked opened this issue May 29, 2020 · 2 comments · Fixed by #79
Closed

ERROR dicom.ReadElement: Undefined length disallowed #82

IChocked opened this issue May 29, 2020 · 2 comments · Fixed by #79

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@IChocked
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This error occurs here in parser.go in the ParseNext() function. Something odd that I don't completely understand is that the tags reported in the error, at least for the two example errors below, don't exist in the file (they aren't printed out with dcmdump).

Example errors:

  • ERROR dicom.ReadElement: Undefined length disallowed for VR=\u0000\u0000, tag (0000,0000)[CommandGroupLength] (file offset 61170)
  • ERROR dicom.ReadElement: Undefined length disallowed for VR=\u0007\u0000, tag (ffdc,ffc4)[??] (file offset 61006)

Sample files
issue82.zip
@suyashkumar
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I think these are happening due to the same issue in #77. I think this because my quick fix branch seems to parse these files with no issues. (PR #79, branch s/native-pixeldata-fix)

@suyashkumar
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feel free to use a build from that branch for evaluating issues. I need to check on some weird behavior I saw with that PR before merging and clean things up, but overall it should unblock you all if you are blocked on it!

@suyashkumar suyashkumar mentioned this issue Jun 8, 2020
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suyashkumar added a commit that referenced this issue Jun 8, 2020
@suyashkumar
Support parsing NativePixelData when it appears multiple times in a D…
9d8d8d9 
…ICOM (#79)

This fixes #77 and appears to work on provided DICOMs. This is a relatively quick fix, that does seem to get the job done. There are some minor improvements that can be made in future PRs, but it will be best to get these changes in to unblock future work.

This also appears to fix #82, and fix #65 (we are able to parse those images without errors).

For most of the provided images, the issue was that an icon image sequence could appear in the DICOMs in addition to the primary PixelData. When reading that particular image sequence, a different set of metadata tags need to be used (instead of the global ones, which apply only to the core PixelData).

There may be additional work to fully and correctly parsing icon image sets (most of the icons seem to be unpopulated in the sample images), but this change will at least prevent the parser from failing on DICOMs like this.
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Support parsing NativePixelData when it appears multiple times in a DICOM suyashkumar/dicom
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@suyashkumar @IChocked