From: A one-dimensional slope detection approach
Pre-smooth
Erf
Tanh
Sigmoid
Ramp
Step
Arctan
0
0.1004
0.0615
0.2323
0.2547
-
0.0692
1
0.0946
0.0484
0.2421
0.2353
0.3519
0.0665
4
0.3529
0.2818
0.7248
0.2840
0.2932
0.4723