Table 1.

Comparison with previous work.

Reference	Basis	Support	Locality param.	IDTa	Regularization	Opt.
Bookstein 1989	TPS	Infinite	None	No	2nd derivative	LEb
Kybic and Uncer 2003	B-spline	Compact	Grid spacing	Yes	No	GDc
Sorzano et al 2005	B-spline	Compact	Grid spacing	Yes	Divergence&curl	GD
Rohr et al 2004	Gaussian RBF	Infinite	Kernel width	Yes	Gaussian filter	GD
Christensen et al 1997	Eigenfunctions	Infinite	None	Yes	2nd derivatives	GD
Rohr et al 2001	TPS	Infinite	None	No	2nd derivatives	LE
Kohlrausch et al 2005	GEBS	Infinite	Kernel width	No	2nd derivative	LE
Fornefett et al 2001	Wendland RBF	Compact	Support radius	No	No	LE
Arad et al 1994	Gaussian RBF	Infinite	Kernel width	No	No	LE
This work	Gaussian RBF	Infinite	Kernel width	No	2nd derivative	LE

^aIntensity data term

^bLinear equations

^cGradient descent