System for assessment reflective objects along a roadway

• US 8,660,311 B2
• Filed: 08/08/2011
• Issued: 02/25/2014
• Est. Priority Date: 08/12/2000
• Status: Expired due to Fees

• Current Assignee: Mandli Communications, Inc., Mandli Inc.
• Original Assignee: Facet Technology Corp.
• Inventors: Retterath, James E., Laumeyer, Robert A.
• Primary Examiner(s): Bella, Matthew
• Assistant Examiner(s): Rosario, Dennis
• Application Number:
  US13/205,337
• Publication Number:
  US 20120065940A1
• Time in Patent Office: 932 Days
• Field of Search: 382/104, 382/105, 382/224
• US Class Current: 382/104
• CPC Class Codes: G01N 21/251 Colorimeters; Construction thereof
• CPC Class Codes: G01N 21/55 Specular reflectivity
• CPC Class Codes: G01N 21/84 Systems specially adapted for particular applications
• CPC Class Codes: G01N 2201/06113 Coherent sources; lasers
• CPC Class Codes: G01N 2201/102 Video camera
• CPC Class Codes: G01N 2201/12 Circuits of general importance; Signal processing
• CPC Class Codes: G01S 17/06 Systems determining position data of a target
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle
• CPC Class Codes: G06V 20/582 of traffic signs
• CPC Class Codes: G08G 1/096758 where no selection takes place on the transmitted or the received information
• CPC Class Codes: G08G 1/096783 where the origin of the information is a roadside individual element

Abstract

A system for the assessment of reflective surfaces disposed along a roadway repeatedly illuminates an area along the roadway that includes at least one reflective surface using a light source. Multiple light intensity values are measured over a field of view which includes at least a portion of the area illuminated by the light source. A computer processing system is used to identifying a portion of the light intensity values associated with a reflective surface and analyze the portion of the light intensity values to determine assessment for that reflective surface. In one embodiment, a virtual nighttime drive through along a roadway is simulated using a plurality of intensity values to simulate reflections from each reflective surface disposed along the roadway during the virtual drive through.

Claims

1. A method for classifying a road sign having sheeting types having at least one color, each sheeting type of a particular color covering at least one non-overlapping area of the road sign, the method comprising the steps of:

using a light source to illuminate at least a portion of the reflective sheeting material covering the road sign as the light source is traversed along the roadway;

collecting a plurality of light intensity measurements reflected from the at least a portion of the reflective sheeting material to generate an as-measured retroreflectivity profile, the light intensity measurements corresponding to exemplary angular displacements of incident light from a reference position;

providing a database of retroreflectivity profiles, each retroreflectivity profile having an associated known sheeting type having a known color;

providing a database of road signs, each road sign categorized according to a set of colors associated with each known sheeting type covering the road sign;

selecting retroreflectivity profiles from the database of retroreflectivity profiles that best correlates to at least a portion of the as-measured retroreflectivity profile;

determining a set of sheeting types associated with the selected retroreflectivity profiles; and

classifying the road sign according to the set of colors associated with the set of determined sheeting types.