05304786 is referenced by 468 patents and cites 10 patents.

A nonvolatile electro-optical read-only memory includes a substrate on which is printed (or otherwise inscribed) a complex symbol or "label" with a high density two-dimensional symbology, a variable number of component symbols or "codewords" per row, and a variable number of rows. Codewords in alternating rows are selected from mutually exclusive subsets of a mark pattern such as a (17,4) mark pattern. The subsets are defined in terms of particular values of a discriminator function, which is illustrated as being a function of the widths of bars and spaces in a given codeword. In the illustrated embodiment, each subset includes 929 available codewords; that, plus a two-step method of decoding scanned data, permitting significant flexibility in defining mappings of human-readable symbol sets into codewords. The memory may be used in conjunction with a scanner and a suitable control system in a number of applications, e.g., robotic operations or automated microfilm searching.

Title
High density two-dimensional bar code symbol
Application Number
7/461881
Publication Number
5304786
Application Date
January 5, 1990
Publication Date
April 19, 1994
Inventor
Jerome Swartz
Old Field
NY, US
Yajium P Wang
Port Jefferson Station
NY, US
Theodosios Pavlidis
Setauket
NY, US
Assignee
Symbol Technologies
NY, US
IPC
G06K 7/10
View Original Source