# What is spatial correlation and spatial convolution?

What does the term spatial correlation and spatial convolution mean with respect to digital image processing ?

• While Spatial Convolution is certainly an operation done over signals defined in Spatial Indices Spatial Correlation can be interpreted either as an operation (Correlation, as a flipped convolution) or a property, namely signal which is values have spatial correlation one with each other. What do you mean? Only as operations?
– Royi
Nov 18, 2019 at 7:42

## 1 Answer

These terms exist mainly for historical reasons. In signal processing the signal is a one-dimensional function of time. So people talk about the time domain vs. the frequency domain. On the other hand, in image processing you are looking at a 2D function of $x$ and $y$, and there is no notion of time. Instead your are talking about spatial frequencies. Hence, spatial correlation and spatial convolution.

Typically, in image processing you simply talk about convolution and correlation. The term spatial usually shows up when 2-D convolution and correlation are introduced to people with background in signal processing.

• If you could please explain these terms extensively. I don't have a feel of what do these terms mean Nov 19, 2013 at 4:23
• To get a feel for those terms you would need to read up on Fourier transform.
– Dima
Nov 19, 2013 at 14:21