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    User name Pascal VERNIN

    Log entry time 16:18:13 on October 23,1998

    Entry number 3317

    keyword=Circular Raster Scanner width

    How to compute the H and V diameter of the raster from ARC scanners?
    In case of elliptical raster (uncorrelated ellipse in the HxV plane),
    let "h" be the H diameter, "v" the vertical one.
    h is measured directly by the width of the horizontal profile (right peak,
    produced by the vertical wire)
    The wire at +45deg. measure a width "m1" (left peak)
    The wire at -45deg. measure a width "m2" (center peak)
    -if the ellipse is uncorrelated, one must measure m1=m2 (=m)
    -then v is given by:
    v=h/(tan(arcsin(h/m))

    A circular patern gives: m*sqrt(2)