| US 7,489,409 B2 | ||
| System for sensing an absolute position in two dimensions using a target pattern | ||
| David C. Chu, Palo Alto, Calif. (US); and Evan R. Whitney, Saratoga, Calif. (US) | ||
| Assigned to Agilent Technologies, Inc., Santa Clara, Calif. (US) | ||
| Filed on May 24, 2007, as Appl. No. 11/753,508. | ||
| Application 11/753508 is a continuation of application No. 11/112623, filed on Apr. 22, 2005, granted, now 7,230,727. | ||
| Prior Publication US 2007/0237413 A1, Oct. 11, 2007 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. G01B 11/14 (2006.01) | ||
| U.S. Cl. 356—614 [356/616] | 18 Claims |
| 1. A system for sensing an absolute two-dimensional position of an object having a two-dimensional target pattern thereon,
the system comprising:
a sensor for capturing an image of a subset of the target pattern; and
a controller for generating a first image vector representing summations of rows of pixel values from the image, and a second
image vector representing summations of columns of pixel values from the image, the controller configured to determine an
absolute two-dimensional position of the subset of the target pattern with respect to the origin of the target pattern based
on the first image vector, the second image vector and target vectors that represent the target pattern.
|