Since the trace *A+C* can never be zero for an ellipse, the arbitrary
scale factor in the coefficients of the conic equation can be naturally
removed by the normalization *A+C=1*. This normalization has been used
by many researchers [17, 21].
All ellipse can then be described by a 5-vector

and the system equation becomes:

where

Given *n* points, we have the following vector equation:

where

The function to minimize becomes

Obtaining its partial derivative with respect to and setting it to zero yield:

The solution is readily given by

This method is known as *pseudo inverse technique*.

Thu Feb 8 11:42:20 MET 1996