Bar code reading instrument which prompts operator to scan bar codes properly

Abstract

A hand-held instrument for reading a bar code symbol, and analyzing the print quality of the code upon manually scanning the code has a graphic display. The display is driven by a computer which has memory (a block in RAM) in which a multiplicity of data samples representing the reflectance profile of the bar code pattern are entered at a constant rate. The print quality analysis is based upon these samples. The number (count) of these samples represents the duration of the elements (bars and spaces) constituting the code. When the number of samples in successive, adjacent characters (groups of elements, a string of which represents a valid code) differs by 25%, the display is driven to prompt the operator to scan the code again, but more evenly without jerky motion (accelerations or decelerations). When the capacity of the memory block allocated to the scan profile data samples is exceeded, the operator is prompted by the display to scan faster. When the average duration of the elements as represented by the average number of samples (counts) in a narrow element in the code is less than six samples, the operator is prompted by the display to scan slower.

Dependencies are inferred from the claim text.