Systems utilizing a high density two dimensional bar code symbology

A robotic system for moving an object that includes a machine-readable label containing a data file structure made up of a plurality of marks having one of two different states, said file structure including

• a plurality of codewords selected from a set of patterns of said marks, wherein each of said codewords represents at least one information-bearing character, and
• at least two rows of said codewords, wherein the codewords in one of said rows are members of a first subset of said set of mark patterns, and the codewords in a second one of said rows are members of a second subset of said set of mark patterns, the first subset of said set of mark patterns being distinguishable from the second subset of said set of mark patterns,
• the robotic system comprising:
• (a) a system for generating a signal representative of the codewords in a memory, said system being capable of concurrently reading a portion of the codewords from each of the two rows by distinguishing the first and second subsets;
• (b) processing means, responsive to said signal, for processing the information-bearing characters in the codewords in said memory and generating control signals from the information-bearing characters;
• and
• (c) a manipulator, coupled to the processing means, for taking certain actions in response to the control signals from the processing means.

A hand-held reader for reading codewords comprising:

• a housing including a transparent portion;
• a beam generator located in the housing for generating a light beam to be directed onto each of the codewords through the transparent portion;
• a light sensitive device, responsive to the beam generator, for detecting light reflected from the codewords and converting the detected light into corresponding electrical signals;
• a signal control unit, responsive to the light sensitive device, for processing the electrical signals to identify the codewords;
• and
• a data file structure used for reading the codewords including:
• at least two rows of the codewords, one row adjacent to and beneath another row;
• each of said codewords representing at least one information-bearing character and being selected from among a set of detectable mark patterns;
• each said mark pattern comprising a pattern of marks, each said mark being representative of one of a plurality of different states;
• the codewords in each row being selected from a subset of said mark patterns, the subset for said row being defined by a specified rule for that row that differs from the rule specified for said adjacent row to allow portions of the codewords from each of the two rows to be read concurrently;
• and
• each said rule being a function of a detectable characteristic of the respective said marks.