---
title: Filters
categories: lecture
---

### Convolution

$$f[x]*h(x) = \sum_{k=-\infty}^{\infty} f[k]h(x-k)$$

+ Note the convolution of a sampled signal and a continuous one
+ [Demo](https://youtu.be/HW4IamyQnzw)

**Note** OpenCV uses correlation instead of convolution.
Conceptually this is different, but in practice, the only effect
is to mirror the filter.