Jonathan David Larson

US Patent:

6404506, Jun 11, 2002

Filed:

Mar 8, 1999

Appl. No.:

09/264828

Inventors:

Harry H. Cheng - Davis CA
Benjamin D. Shaw - Vacaville CA
Joe Palen - Davis CA
Jonathan E. Larson - Davis CA
Xudong Hu - Davis CA
Kirk Van Katwyk - Tracy CA

Assignee:

The Regents of the University of California - Oakland CA

International Classification:

G01B 1102

US Classification:

356634, 356635, 356636, 356614, 356615, 25055922, 25055926

Abstract:

In current practice, quantitative traffic data is most commonly acquired from inductive loops. In addition, video-image processing or time-of-flight laser systems can be used. These methods all have problems associated with them. Therefore, we have developed a new type of non-intrusive laser-based detection system for measurement of vehicle travel time. The system employs a fan angle laser, an image lens, a set of cylindrical optics, a linear photodetector array, and associated signal processing hardware and software. The system is positioned above the plane of detection and configured such that it can unambiguously find the object boundaries in all lighting conditions independent of the time-of-flight of the laser. Instead of depending upon the reflectance of the object being detected, or determination of the range or distance from the detector to the object being detected, the invention reflects the laser off of the pavement or other roadway surface. The lack of a reflection determines the size, shape, and âpresenceâ of the vehicle, and the system is capable of determining the length and width of moving objects, as well as travel time, in real time with high resolution.