This paper proposes a new affine registration algorithm
for matching two point sets in IR2 or IR3. The input point
sets are represented as probability density functions, using
either Gaussian mixture models or discrete density models,
and the problem of registering the point sets is treated
as aligning the two distributions. Since polynomials transform
as symmetric tensors under an affine transformation,
the distributions’ moments, which are the expected values
of polynomials, also transform accordingly. Therefore, instead
of solving the harder problem of aligning the two distributions
directly, we solve the softer problem of matching
the distributions’ moments. By formulating a least-squares
problem for matching moments of the two distributions up
to degree three, the resulting cost function is a polynomial
that can be efficiently optimized using techniques originated
from algebraic geometry: the global minimum of this polynomial
can be determined by solving a syst...