Patent ID: 8660311

Claim:
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.