Seeing in Frequency2026-11-11computer‑visionfourier‑transformconvolution‑theoremfrequency‑domainnotch‑filterdifference‑of‑gaussiansimage‑pyramidsaliasingimage‑processingcomp9517agenticImages as sums of waves: the convolution theorem, what a real spectrum looks like, deleting a periodic artefact with a notch, the difference of Gaussians as a band-pass filter, and Gaussian and Laplacian pyramids.