Ning Chang

US Patent:

55154522, May 7, 1996

Filed:

Dec 31, 1992

Appl. No.:

7/999294

Inventors:

John A. Penkethman - Gilroy CA
Robert A. Harrison - Morgan Hill CA
Xiaoming Wang - San Jose CA
Ning S. Chang - Sunnyvale CA
Arye Green - San Jose CA

Assignee:

Electroglas, Inc. - Santa Clara CA

International Classification:

G06K 900

US Classification:

382141

Abstract:

An improved illumination method and apparatus for optical character recognition. A first light source is positioned such that light emitted from it strikes the surface at an angle of incidence. A detector is placed at the angle of reflection, such that specularly reflected light strikes the detector, providing bright field illumination. Additional light sources positioned at angles different from the first light source are disclosed to provide for high and low angle dark field illumination. Novel light guides which allow for a compact and economic system design are also disclosed. The disclosed system utilizes light sources and filters which greatly reduce the effect of environmental lighting on the optical character recognition process. A novel method to select the optimum light source and intensity is also disclosed.

US Patent:

45123497, Apr 23, 1985

Filed:

May 13, 1983

Appl. No.:

6/494173

Inventors:

Thomas K. Hunt - San Francisco CA
William H. Goodson - San Francisco CA
Ning Chang - San Francisco CA
David R. Knighton - San Francisco CA
Finn Gottrup - Hojbjerg, DK
Richard Firmin - London, GB2

Assignee:

Regents of the University of California - Berkeley CA

International Classification:

A61B 500

US Classification:

128632

Abstract:

A new method of tissue oxygen tension measurement which is suitable for human use utilizes an implanted Silastic tube which is inserted through four to five cm of subcutaneous tissue leaving the ends exposed. With the tube filled, for example, with a saline solution, reference and oxygen electrodes are inserted at the exposed ends and by the use of a polarographic potential the amount of oxygen which permeates through the tube from the tissue into the saline solution may be measured on a continuous real-time basis.