Table 1.

Parameter selection

Parameter		Value/range	Notes
Sliding filter	rad	20–30 (voxel)	This parameter determines the size of the support region of SVF and SBF. Too large or too small of a region will lead to computation-intensive processes or a reduction in the quality of seeding point selection and radius estimation.
	d	8 (voxel)	This parameter is the width of the sliding volume and sliding band, and it remains constant in the following experiments.
	L	20	This parameter remains constant in the following experiments. Too large of an L value will lead to computationally intensive processes.
	R max	rad-d/2	This parameter is same in seeding and radius estimation.
	R min	(d/2, rad-d/2)	This parameter is same in seeding and radius estimation. If the datasets are generated from bright field microscopy, a larger R min should be set. Otherwise, a smaller R min should be set.
	n	8–32	The larger the n value, the better the radius estimation and the lower the computation efficiency.
	T	0.7	This parameter is the threshold used to select the coarse seeding points, and it remains constant in the following experiments.
SEF-Open curve snake	t	10–25	In most experiments, 10 is sufficient for the curve evolution in the GVF field of volume after SVF enhancement.
	γ	2	This parameter controls the steps of evolution, and it is a fixed constant in following experiments.
	ɑ	0.8	This parameter representing the elasticity coefficient remains constant in the following experiments. A larger ɑ value makes the open snake smoother.
	β	β(s) = 0.2, 0 < s < 1	This parameter of the stiffness coefficient remains constant in the following experiments. A larger β value makes the snake stiffer.
		β(s) = 0, s = 0 or s = 1