Table 1 Parameter selection

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