Method and apparatus for encoding and decoding bar codes with primary and secondary information and method of using such bar codes

Abstract

A bar code ( ) has primary information ( ) encoded in one direction (e.g., horizontally) and secondary information ( ) encoded in another direction (e.g., vertically) in single ( ) or multiple tracks ( ) in selected ones of the vertical bars ( ) of a bar code ( ). Using a non-linear, variable amplitude scanner, all of the primary bars are scanned in the one direction to obtain all of the primary information and all of those vertical bars having secondary information are scanned in the other direction to obtain all of the secondary information. The one direction which is perpendicular to the vertical primary bars ( ), is determined by first rotating the scan path axis ( ) until both start ( ) and end ( ) code bars are read thereby placing the scan path entirely within the total bar code, and, then, further rotating the scan path ( ) to determine the direction of the minimum crossing width (Lsc ) of the total bar code ( ). Secondary information is scanned in planes orthogonal to the one direction after those vertical bars ( ) having such information are first identified and selected. In a preferred embodiment, the decoded secondary information may be used to control selected station process operations for selected products in a continuous manufacturing assembly line.