Linear shift-invariant Image Filtering


Convolution
Replace each pixel by a linear combination of its neighbors (and possibly includes itself)
박스로 적용하는 게 아니라 픽셀별로 적용




### Examples
- blur $\begin{pmatrix}1 & 1 & 1 \\1 & 1 & 1 \\1 & 1 & 1 \\\end{pmatrix}$







