possible error in docs?

Posted by Aryeh Weiss on
URL: http://imagej.273.s1.nabble.com/possible-error-in-docs-tp5017241.html

I was looking for how ImageJ calculates roundness, and I found the
following:
/
Shape descriptors/ Calculates and displays the following shape descriptors:

  *
    /Circularity/ /4/π/ × [/Area/][/Perimeter/]^2 / with a value of 1.0
    indicating a perfect circle. As the value approaches 0.0, it
    indicates an increasingly elongated shape. Values may not be valid
    for very small particles. Uses the heading*Circ*.
  *
    /Aspect ratio/ The aspect ratio of the particle’s fitted ellipse,
    i.e., [/Major/ /Axis/][/Minor/ /Axis/]. If */Fit Ellipse/* is
    selected the*Major* and *Minor* axis are displayed. Uses the
    heading*AR*.
  *
    /Roundness/ 4 × [/Area/]/π/ × [/Major/ /axis/]^2 or the inverse of
    /Aspect Ratio/. Uses the heading *Round*.

https://imagej.nih.gov/ij/docs/guide/146-30.html

I think that the 4  in the Roundness  definition is not correct, and it
should be Area/[pi*(Major Axis)^2],
and not 4 x Area /[pi*(Major Axis)^2]

Am I correct?

--aryeh

--
Aryeh Weiss
Faculty of Engineering
Bar Ilan University
Ramat Gan 52900 Israel

Ph:  972-3-5317638
FAX: [phone]


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