
parameters are adjusted iteratively to deform the model surface so that most of
the input 3-D data points are near the surface.
To summarize, a superquadric surface is defined by a single analytic function
that can be used to model a large set of structures such as spheres, cylinders,
parallelepipeds, and shapes in between. Further, superquadric parameters can
be adjusted to include such deformations as tapering, bending, and cavity
deformation [97]. For example, superellipsoids may be used to estimate
the 3-D bounding surface of biological cells. The inside–outside cost function
F(x, y, z) of a superellipsoid surface is defined by
Fx, y, zðÞ¼
x
a
1
2=