Hypercolumns in area V1 contain frequency- and orientation-selective simple
and complex cells for line (bar) and edge coding, plus end-stopped cells for key-
point (vertex) detection. A single-scale (single-frequency) mathematical model
of single and double end-stopped cells on the basis of Gabor filter responses was
developed by Heitger et al. (1992 Vision Research 32 963-981). We developed
an improved model by stabilising keypoint detection over neighbouring micro-
scales
