[vtkusers] Curvature in respect to size of surface

[Boettcher, Dr. Peter]

vtkCurvature calculates the mean or gauss curvature of a surface. However the interpretation what one would consider a considerable curvature (been not flat) may depend on the size of the surface considered. For example taking a 5 mm area of a 10 cm sphere would be flat in average, in contrast to a 2 cm big area which will be convex.  Currently I use the following approach. At each point of the surface I clip the surface around that point of the diameter which I am interested in. Than I measure the angle between the surface normal at the centre and the surface normals at the other points of the clipped portion of the surface. Finally the mean angle is calculated, representing the deviation from been flat. A mean angle of 0 would mean the surface is flat. Unfortunately this approach does not differentiate between concave and convex and mixed surfaces. 

Are there already established algorithms measuring the curvature in respect to the size of the surface investigated?

 

Regards, Peter. 

 
------------------------------------
Peter Böttcher, Dr med vet, DipECVS
European Veterinary Specialist in Surgery
Fachtierarzt für Kleintierchirurgie
Klinik für Kleintiere 
Universität Leipzig 
An den Tierkliniken 23 
D-04103 Leipzig (Germany)
Tel: +49-341-9738700 
Fax: +49-341-9738799
email: boettcher at kleintierklinik.uni-leipzig.de

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