version 1.4.16x dicom header compression info

    Hi,


    I been partially moving previously stored dicom data in J1 compression to Jpeg2000 lossless to further reduce file size.
    Review of saved files show that dicom header UID tranfer syntax is Jpeg2000 lossless however the previously inserted J1 header remains intact. Is this a proper behaviour or should have the J1 header been appended or removed?


    sample header


    (0002,0000) UL 200 # 4 MetaElementGroupLength
    (0002,0001) OB \00\01 # 2 FileMetaInformationVersion
    (0002,0002) UI [1.2.840.10008.5.1.4.1.1.2] # 26 MediaStorageSOPClassUID
    (0002,0003) UI [1.3.12.2.1107.5.1.4.54546.30000006042500365681200000178] # 56 MediaStorageSOPInstanceUID
    (0002,0010) UI [1.2.840.10008.1.2.4.90] # 22 TransferSyntaxUID
    (0002,0012) UI [1.2.826.0.1.3680043.2.135.1066.101] # 34 ImplementationClassUID
    (0002,0013) SH [1.4.16/WIN32] # 12 ImplementationVersionName
    (0008,0000) UL 1246 # 4 IdentifyingGroupLength
    (0008,0005) CS [ISO_IR 100] # 10 SpecificCharacterSet
    (0008,0008) CS [DERIVED\\SECONDARY\\AXIAL\\CT_SOM5 RTD ] # 36 ImageType
    .
    . header data inserted from dcmtk tools in 1.4.15x


    (0008,2111) ST [Lossless JPEG compression, selection value 1, point transform 0, compression ratio 2.2878 [Lossless JPEG compression, selection value 1, point transform 0, compression ratio 1.7158] ] # 182 DerivationDescription
    (0008,2112) SQ (empty) # 0 SourceImageSequence
    (0008,0000) UL 92 # 4 IdentifyingGroupLength
    (0008,1150) UI [1.3.12.2.1107.5.9.1] # 20 ReferencedSOPClassUID
    (0008,1155) UI [1.3.12.2.1107.5.1.4.54546.30000006042500365681200000176] # 56 ReferencedSOPInstanceUID
    (0008,9215) UN (empty) # 0 ?
    (0008,0000) UL 90 # 4 IdentifyingGroupLength
    (0008,0100) SH [121327] # 6 CodeValue
    (0008,0102) SH [DCM ] # 4 CodingSchemeDesignator
    (0008,0104) LO [Full fidelity image, uncompressed or lossless compressed] # 56 CodeMeaning
    (0009,0000) UL 28 # 4 GroupLength


    ajgg

    Hi,


    this may be called a bug. Our compression code only changes a few header items. Can you specify in detail what would be the required behavior, or maybe look it up in the DICOM standard.


    Thanks,


    Marcel

    Hi,


    Ive been trying to reproduce the error, but cannot seem to make it reappear.
    Im only getting correct UID syntax transfer for Jpeg2000 and old dcmcjpeg inserted J1 header all in same image.



    (0002,0010) UI [1.2.840.10008.1.2.4.90] # 22 TransferSyntaxUID


    (0008,1140) SQ (empty) # 0 ReferencedImageSequence
    (0008,0000) UL 98 # 4 IdentifyingGroupLength
    (0008,1150) UI [1.2.840.10008.5.1.4.1.1.2] # 26 ReferencedSOPClassUID
    (0008,1155) UI [1.3.12.2.1107.5.1.4.54546.30000006092106470181200000911] # 56 ReferencedSOPInstanceUID
    (0008,2111) ST [Lossless JPEG compression, selection value 1, point transform 0, compression ratio 2.5303 ] # 90 DerivationDescription
    (0008,2112) SQ (empty) # 0 SourceImageSequence

    ajgg

    Another location could be the line


    BlockSize = 4096


    in pdata.cxx (this is some ancient UCDavis code that I never touched).


    You could try and change the number 4096 to 8192 that and see if the behavior changes.


    Once we know the culprit we can zoom in to the problem further.


    Marcel

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