A MAP holds the corners

Who holds the leash?

What Holds Up a Plane ?

To the Editor: Bob Colwell’s discussion of lift (“Leave Bernoulli Out of This,” At Random, May 2003, pp. 10-12) is better informed than many elementary texts on the subject, but it leaves out a more interesting question about how wings fly. Colwell points out the errors in the usual explanation—the one that depends on a wing’s greater curvature on top. His excellent counterexamples are that fla...

Who Holds Up the World?

Finding Corners

Many important image cues such as 'T'-,'X'and 'L'junctions have a local two-dimensional structure. Conventional edge detectors are designed for one-dimensional 'events'. Even the best edge operators can not reliably detect these two-dimensional features. This contribution proposes a solution to the two-dimensional problem. In this paper, I address the following: • 'L'-junction detection. Previo...

Cutting Corners