From: A scale-based forward-and-backward diffusion process for adaptive image enhancement and denoising
Sample method
σ 1
Logarithmic
{0.5, 1, 2, 4, 8, 16}
Linear
{0.5, 1, 1.5, 2, 2.5, 3}
Limited-Log
{0.5, 1, 2}
Linear-Log
{0.5, 1, 2, 3, 4, 5}