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  • PixelData Value Representation for various Transfer Syntaxes

    From giacomo.petronio@gmail.com@21:1/5 to All on Tue Oct 20 06:00:05 2020
    Is it always ok to use OW as the VR PixelData for every transfer syntax?

    Reading DICOM PS3.5 2020d - Data Structures and Encoding:
    A.1 DICOM Implicit VR Little Endian Transfer Syntax
    A.2 DICOM Little Endian Transfer Syntax (Explicit VR)
    A.4 Transfer Syntaxes For Encapsulation of Encoded Pixel Data

    To me it seems so, but for encapsulated TS, where:
    "Pixel Data (7FE0,0010) may be encapsulated or native. (...) If encapsulated, it has the Value Representation OB".

    But with various tools, when I compress an image using an encapsulated TS (e.g. JPEG Lossless), I see that the PixelData VR is OW.

    What am I missing?

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  • From Mathieu Malaterre@21:1/5 to giacomo....@gmail.com on Tue Oct 20 12:17:38 2020
    On Tuesday, October 20, 2020 at 3:00:12 PM UTC+2, giacomo....@gmail.com wrote:
    Is it always ok to use OW as the VR PixelData for every transfer syntax?

    Reading DICOM PS3.5 2020d - Data Structures and Encoding:
    A.1 DICOM Implicit VR Little Endian Transfer Syntax
    A.2 DICOM Little Endian Transfer Syntax (Explicit VR)
    A.4 Transfer Syntaxes For Encapsulation of Encoded Pixel Data

    To me it seems so, but for encapsulated TS, where:
    "Pixel Data (7FE0,0010) may be encapsulated or native. (...) If encapsulated, it has the Value Representation OB".

    But with various tools, when I compress an image using an encapsulated TS (e.g. JPEG Lossless), I see that the PixelData VR is OW.

    It is required to be OB. There was a bug in GDCM (and possibly derivatives) but it has been fixed in latest versions. Which tool(s)/version(s) were you using ?

    What am I missing?

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  • From giacomo.petronio@gmail.com@21:1/5 to All on Wed Oct 21 01:47:53 2020
    Il giorno martedì 20 ottobre 2020 alle 21:17:40 UTC+2 Mathieu Malaterre ha scritto:
    It is required to be OB. There was a bug in GDCM (and possibly derivatives) but it has been fixed in latest versions. Which tool(s)/version(s) were you using ?

    Thanks for the answer, I double-checked, and I was wrong: compressed images do have PixelData VR=OB.
    I've tried with gdcmconv (GDCM 3.0.4) and dcmcjpeg (dcmtk-3.6.5), and verified with dcmdump of both tools.

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