They found that the curvature κ = κ(x, y) defined by κ = ▽ · ∇u could be used to modify the |∇u| diffusion coefficient Dˆ by introducing a function g = g(|κ|) within it. This way the geometric information encoded in κ is used to strengthen the diffusion coefficient where necessary. The new diffusion coefficient Dˆ is then given by