[Insight-users] elongation implementation not matching its definition

[Cagatay Bilgin]

Hello everyone,

Either I am missing something or the write up about the elongation is not
matching the actual implementation.

"elongation is computed as the ratio of the largest principal moment by the
smallest principal moment. "

however in itkShapeLabelMapFilter.hxx elongation is defined as largest
principal moment / second largest principal moment. In 3D the definition
and the implementation becomes inconsistent.

from itkShapeLabelMapFilter.hxx
331  elongation = vcl_sqrt(principalMoments[ImageDimension - 1] /
principalMoments[ImageDimension - 2]);
332  flatness = vcl_sqrt(principalMoments[1] / principalMoments[0]);

Cheers,
C. Cagatay Bilgin

-- 
Cemal Cagatay Bilgin, PhD
Life Sciences Division
Lawrence Berkeley National Lab
MS977, One Cyclotron Road
Berkeley, CA 94720, USA
Email: ccbilgin at lbl.gov
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.itk.org/pipermail/insight-users/attachments/20130822/994fe3f3/attachment.htm>