Article marker and decoding method

摘要

A graphical symbol encoding a numerical value may be accurately read even when placed on a non-planar surface. The marker is imaged with an inventive apparatus and analyzed using an inventive method which translates the graphical image into a unique number for article identification purposes. The marker in its preferred embodiment includes an outer ring having a continuous perimeter in one or more concentric data tracks disposed within this outer ring. A timing track is used to determine angular relationships about the center of the marker. Distances between points associated with the outer ring in a particular data track are used in conjunction with these angular relationships to locate a digitally encoded visual pattern associated with a particular data track, this pattern being used to store at least a portion of a numerical code used to identify each marker-bearing article.