Vehicle classification and axle counting sensor system and method

• US 20020140924A1
• Filed: 10/16/2001
• Published: 10/03/2002
• Est. Priority Date: 01/08/1999
• Status: Abandoned Application

• Current Assignee: John T. Myers, Richard J. Wangler, Robert E. Mcconnell II, Robert L. Gustavson
• Original Assignee: John T. Myers, Richard J. Wangler, Robert E. Mcconnell II, Robert L. Gustavson
• Inventors: Gustavson, Robert L., Wangler, Richard J., Myers, John T., McConnell, Robert E. II
• Application Number:
  US09/981,292
• Publication Number:
  US 20020140924A1
• Time in Patent Office: Days
• US Class Current: 356/28
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01S 7/4817 relating to scanning
• CPC Class Codes: G08G 1/015 with provision for distinguishing between two or more types of vehicles, e.g. between motor-cars and cycles
• CPC Class Codes: G08G 1/04 using optical or ultrasonic detectors

Abstract

A vehicle detection and classification sensor provides accurate 3D profiling and classification of highway vehicles for speeds up to 100 mph. A scanning time-of-flight laser rangefinder is used to measure the distance to the highway from a fixed point above the road surface and then measure the distance to the surfaces of any vehicle that is viewed by the sensor. The beam is pulsed at a high repetition rate for determining vehicle speeds with a high accuracy and uses the calculated speed and consecutive range measurements as the vehicle moves past the sensor to develop a three-dimensional profile of the vehicle. An algorithm is applied to the three-dimensional profile for providing a vehicle-classification. A laser is also used to count the number of axles associated with the vehicle.

Claims

1. A method for determining a vehicle profile useful in classifying the vehicle and for counting the number of axles carried by the vehicle, the method comprising the steps of:

scanning a laser range finder beam transversely across a vehicle traveling through a sensing zone of the sensor for determining the range for a plurality of points on the vehicle;

determining an orientation of the beam for each of the plurality of points on the vehicle;

determining a vehicle speed;

processing the ranges and corresponding beam orientations for forming a set of two dimensional cross-sectional profiles of the vehicle;

positioning the profiles based on the vehicle speed;

providing a three-dimensional representation of the vehicle for classification thereof; and

emitting a laser beam toward the vehicle for determining the number of axles carried by the vehicle.