Multidimensional discrete convolution
In signal processing, multidimensional discrete convolution refers to the mathematical operation between two functions f and g on an n-dimensional lattice that produces a third function, also of n-dimensions. Multidimensional discrete convolution is the discrete analog of the multidimensional convolution of functions on Euclidean space.
Source: Wikipedia — Multidimensional discrete convolution (CC BY-SA 4.0)