We derive five new particle flow algorithms for
nonlinear filters based on the small curvature
approximation inspired by fluid dynamics. We find it
extremely interesting that this physically motivated
approximation generalizes two of our previous exact flow
algorithms, namely incompressible flow and Gaussian flow.
We derive a new algorithm to compute the inverse of the
sum of two linear differential operators using a second
homotopy, similar to Feynman's perturbation theory for
quantum electrodynamics as well as Gromov's h-principle.
"Small curvature particle flow for nonlinear filters", Proc. SPIE 8393, Signal and Data Processing of Small Targets 2012, 83930A (15 May 2012); doi: 10.1117/12.915183; https://doi.org/10.1117/12.915183