Seeing in Frequency

Wed, 11 Nov 2026 21:00:00 +1100

Spatial filtering slides a small kernel over the pixels. This page looks at the same image through a different lens: as a sum of waves. In that view blurring keeps the slow waves and throws away the fast ones, a periodic artefact is a handful of bright dots that can be deleted one by one, and an edge detector is a filter that keeps a ring of middle frequencies. The Fourier transform is the change of lens; the convolution theorem is what makes it worth the trouble, because it turns convolution into multiplication. 𐃏

Image-Pyramids on Aayush Bajaj's Augmenting Infrastructure

Seeing in Frequency