Abstract

A planar curve may convey information at several levels of detail. Consider the top-left curve in Figure 3. It can be perceived as a sequence of wiggles on a quasi-sinusoidal line slightly drifting downward. Note that three different resolutions are involved. Locating the curve extrema with the best precision, while trivial for human perception, presents considerable difficulties for computer vision.

© 1987 Optical Society of America