Symagery Microsystems Inc.

Alex Roustaei

John Scott-Thomas

Wenji Xia

Paul Vulpoiu

Dennis G Priddy

An improved optical code reading system and method that enhances the ability of a reader to locate a symbol within a field of view and enhances the error-correcting properties of the encoding scheme commonly used in 2D bar codes. The reader offsets the effects of damaged finder patterns and missing symbol perimeters and, thereafter, detects high-level symbol information such as the code type, symbol size, and the number of rows and columns in the symbol. The reader then identifies those missing portions of a damaged symbol and marks each missing data bit location with a predetermined indicator. A decoding algorithm then interprets the missing bit indicator as an error of known location (e.g., an &ldquo;erasure&rdquo;), thereby nearly doubling the error correcting strength of all bar codes employing the Reed-Solomon error correction scheme.

Apparatus and method for decoding damaged optical codes

This invention is directed to a method and apparatus for determining the level of ambient light impinging on a selected number of pixels in an imaging array where each pixel includes a photodiode. The ambient light may be determined by resetting the pixels in the array and by detecting current flow through the photodiodes in a selected number of the pixels as they are being reset. Alternately, the ambient light may be determined by resetting a selected number of the pixels in the array and by detecting current flow through the photodiodes in the selected number of the pixels as they are being reset. The photodiodes are reset by applying a reverse bias voltage across them and the current flow is detected by measuring the current flow through a resistance in parallel to the selected photodiodes. The selected number of pixels may be divided into one or more groups each having at least one pixel, and the pixels in each group may be arranged in specific patterns within the array. The array may be laid out in rows and columns, and the groups may be located in predetermined rows or columns. When only a selected number of pixels are reset and these pixels are divided into groups, the groups may be sequentially reset to permit differentiation between the groups.

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La Jolla, CA, United States of America

Alex Roustaei