Simulation of neural contour mechanisms: from simple to end-stopped cells.
Early stages of visual form processing were modelled by simulating cortical simple, complex and end-stopped cells. The computation involves (1) convolution of the image with even and odd symmetrical orientation selective filters (S-operators), (2) combination of even and odd filter outputs to a local energy measure (C-operator), (3) "differentiation" of the C-operator maps along the respective orientation (single and double end-stopped operators) and (4) determination of local maxima ("key-points") of the combined end-stopped operator activity. While S- and C-operators are optimised for the representation of 1-D features such as edges and lines, the end-stopped operator responses at the key-points make explicit 2-D signal variations such as line ends, corners and segments of strong curvature. The theoretical need for this complementary representation is discussed. The model was tested on grey-valued images.
Heitger
F
F
Communication Technology Laboratory, Swiss Federal Institute of Technology ETH, Zurich.
Rosenthaler
L
L
von der Heydt
R
R
Peterhans
E
E
Kübler
O
O
D005374:Filtration; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D008433:Mathematics; D008959:Models, Neurological; D012399:Rotation; D014793:Visual Cortex / Q000502:physiology