Re: Patch for sane.tex (image polarity)

From: Nick Lamb (njl98r@ecs.soton.ac.uk)
Date: Mon Oct 02 2000 - 22:42:39 PDT

  • Next message: Henning Meier-Geinitz: "Re: Patch for sane.tex (image polarity)"

    On Sat, Sep 30, 2000 at 07:56:25PM -0700, David Mosberger-Tang wrote:
    > >>>>> On Sat, 30 Sep 2000 17:13:15 +0200, Henning Meier-Geinitz <hmg-ml@gmx.de> said:
    >
    > Henning> For all other bit depths, larger values mean more red,
    > Henning> green, blue, or white.
    >
    > This is potentially very confusing. Depending on whether you're
    > dealing with a subtractive or additive color synthesis, "more color"
    > could mean darker or brighter, respectively. I no expert in color
    > theory, but perhaps "larger values correspond to more luminous
    > (``brighter'') pixels" would be more accurate and but still clear?

    No experts here, I will crib from the TIFF documentation, while trying
    to stay with SANE's terminology. Actually I think there's little risk
    of people trying to do image acquisition with subtractive color models
    (think about it). How about:

    In frames of type SANE_FRAME_GRAY, when the bit depth is 1 there are
    only two sample values possible, 1 represents minimum intensity (black)
    and 0 represents maximum intensity (white).
    For all other bit depth and frame type combinations, a sample value of 0
    represents minimum intensity and larger values represent increasing
    intensity.

    (I think TIFFs choice of vocabulary "intensity" is appropriate because
    just what /is/ brighter about more xray radiation or infrared?)

    Actually, can anyone tell me (from practical experience) whether I
    am right that this only affects SANE_FRAME_GRAY? Do we have devices
    that actually send 1bit RGB frames?

    Nick.

    --
    Source code, list archive, and docs: http://www.mostang.com/sane/
    To unsubscribe: echo unsubscribe sane-devel | mail majordomo@mostang.com
    



    This archive was generated by hypermail 2b29 : Mon Oct 02 2000 - 23:11:31 PDT