LUTs - DICOM

This is a discussion on LUTs - DICOM ; Hi! Im very confused about LUT's in a dicom viewer environment. Which LUT take the viewer for the image when: - in the dicom image present a modality LUT - no LUT in dicom image And what is a presentation ...

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Thread: LUTs

  1. LUTs

    Hi!

    Im very confused about LUT's in a dicom viewer environment.

    Which LUT take the viewer for the image when:

    - in the dicom image present a modality LUT
    - no LUT in dicom image

    And what is a presentation state? A external LUT defined from
    the user?

    Greets Funke



  2. Re: LUTs

    "Funke Kaiser" wrote in message news:...
    > Hi!
    >
    > Im very confused about LUT's in a dicom viewer environment.
    >
    > Which LUT take the viewer for the image when:
    >
    > - in the dicom image present a modality LUT
    > - no LUT in dicom image
    >
    > And what is a presentation state? A external LUT defined from
    > the user?
    >
    > Greets Funke


    Funke

    Try looking at Supplement 22
    ftp://medical.nema.org/medical/dicom/final/sup22_ft.pdf
    it has all the LUT material all in one place instead of distributed
    into the different DICOM Part Volumes

    Take particular note of the drawing showing the pipeline/order of
    precedence for Modality LUTs (used to produce the actual modality
    output values) and Value Of Interest LUTs (used to modify the modality
    output values emphasize or de-emphasize certain values when the image
    is displayed or printed).

    Yes, a presentation state is a standalone object, separate from the
    image which can contain, among other things, LUTs where a user or
    other device has defined a LUT which records the Value Of Interest
    used to display the image. Calling it "standalone" is probably a
    misnomer here since, although it is a separate object from the image,
    the object has links specifying the image or images to which it
    applies and therefore really cannot "stand alone" from those images.

  3. Re: LUTs

    I would strongly suggest not looking at Sup 22, or any of the
    supplements, but instead Annex N of Part 4, which describes
    the grayscale pipeline from images (instead of print) in
    great detail, and in particular addresses some of the
    exception cases (e.g. XA and XRF). Softcopy and print differ
    in a number of ways.

    You must also read section C.11 of Part 3, which is devoted
    to the encoding and interpretation of the various lookup tables,
    and has numerous notes elaborating on specific examples.

    David

    Eric Goodall wrote:

    > "Funke Kaiser" wrote in message news:...
    >
    >>Hi!
    >>
    >>Im very confused about LUT's in a dicom viewer environment.
    >>
    >>Which LUT take the viewer for the image when:
    >>
    >>- in the dicom image present a modality LUT
    >>- no LUT in dicom image
    >>
    >>And what is a presentation state? A external LUT defined from
    >>the user?
    >>
    >>Greets Funke

    >
    >
    > Funke
    >
    > Try looking at Supplement 22
    > ftp://medical.nema.org/medical/dicom/final/sup22_ft.pdf
    > it has all the LUT material all in one place instead of distributed
    > into the different DICOM Part Volumes
    >
    > Take particular note of the drawing showing the pipeline/order of
    > precedence for Modality LUTs (used to produce the actual modality
    > output values) and Value Of Interest LUTs (used to modify the modality
    > output values emphasize or de-emphasize certain values when the image
    > is displayed or printed).
    >
    > Yes, a presentation state is a standalone object, separate from the
    > image which can contain, among other things, LUTs where a user or
    > other device has defined a LUT which records the Value Of Interest
    > used to display the image. Calling it "standalone" is probably a
    > misnomer here since, although it is a separate object from the image,
    > the object has links specifying the image or images to which it
    > applies and therefore really cannot "stand alone" from those images.



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