Picking the right scale
A difference-of-Gaussians response computed live at the centre of five bright discs. Each disc answers strongest at the sigma that matches its own radius, which is what "scale selection" means before any pyramid is built.
Try this
Sweep sigma from small to large and watch the peak response walk from the smallest disc to the largest.
Try it: find each blob at its own scale
This lab has no article yet. It is here because the idea is worth playing with on its own.
More in edges and features
- An edge, and its two derivatives — One row of pixels, with the first and second derivative stacked underneath.
- Canny, one stage per panel — Smoothing and the two hysteresis thresholds, on a real photo.
- Flat, edge, or corner — Drag a window over a photo; two eigenvalues deliver the verdict.