LUT in grayscale images - DICOM

This is a discussion on LUT in grayscale images - DICOM ; People: I hope you can help me with the following problem. I am trying to display 12-bit grayscale CR images that have been captured in an AFGA system. When I realized that my usual code was not handling them correctly, ...

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Thread: LUT in grayscale images

  1. LUT in grayscale images

    People:

    I hope you can help me with the following problem. I am trying to
    display 12-bit grayscale CR images that have been captured in an AFGA
    system.

    When I realized that my usual code was not handling them correctly, I
    started digging into the VRs and realized that there was a LUT sequence
    in there. The actual name of the tag escapes me at the moment, I am
    not at my work machine.

    So, the question is, how do I use this LUT? Do I do the rescale
    intercept calculation, then apply this to the whole image before I
    apply the window/leveling step?

    Thanks for any help you can provide.

    -carlos rodriguez


  2. Re: LUT in grayscale images

    Check out Part 3 DICOM conformance
    C.11.2.1.2 Window center and window width
    Hope this 'll help u

    Bye
    Prasad

    "buzzword" wrote in message news:<1107492145.539382.124590@g14g2000cwa.googlegroups. com>...
    > People:
    >
    > I hope you can help me with the following problem. I am trying to
    > display 12-bit grayscale CR images that have been captured in an AFGA
    > system.
    >
    > When I realized that my usual code was not handling them correctly, I
    > started digging into the VRs and realized that there was a LUT sequence
    > in there. The actual name of the tag escapes me at the moment, I am
    > not at my work machine.
    >
    > So, the question is, how do I use this LUT? Do I do the rescale
    > intercept calculation, then apply this to the whole image before I
    > apply the window/leveling step?
    >
    > Thanks for any help you can provide.
    >
    > -carlos rodriguez


  3. Re: LUT in grayscale images

    Dear Carlos,

    if I remember correctly (I don't have the DICOM standard at hand,
    currently...) the application of a VOI LUT and the application of
    Window Center / Window Width display transformations are ALTERNATIVE
    steps, that is, a DICOM file should contain one or the other, but NOT
    BOTH.

    Hence, I believe you should apply "modality" transformations (rescale
    slope / intercept), then the VOI LUT, if it is present in your DICOM
    file.

    Hope it helps,

    Marco.


    "buzzword" wrote in message news:<1107492145.539382.124590@g14g2000cwa.googlegroups. com>...
    > People:
    >
    > I hope you can help me with the following problem. I am trying to
    > display 12-bit grayscale CR images that have been captured in an AFGA
    > system.
    >
    > When I realized that my usual code was not handling them correctly, I
    > started digging into the VRs and realized that there was a LUT sequence
    > in there. The actual name of the tag escapes me at the moment, I am
    > not at my work machine.
    >
    > So, the question is, how do I use this LUT? Do I do the rescale
    > intercept calculation, then apply this to the whole image before I
    > apply the window/leveling step?
    >
    > Thanks for any help you can provide.
    >
    > -carlos rodriguez


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