the original image is shown in (a).
Figure (b) contains only sudden intensity changes, called "zero-level crossing".
Figure (c) is the result of analysis on (b) by edge detectors and (d) by bar detectors.
Edges are isolated lines and bars are formed out of two nearby parralllel segments.
Figure (c) and (d) are then encoded in terms of the position; orientations, lenghts and widths of edges and bars.
Figure (c) and (d) are primal sketches of the scenes in (a)

Offside commentary...

Des explications et un hors sujet !

19 Septembre 2002