Browse Prior Art Database

Barcode Quality Filters

IP.com Disclosure Number: IPCOM000112758D
Original Publication Date: 1994-Jun-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Kishi, GT: AUTHOR

Abstract

This article describes a series of tests to insure high quality reading of barcode characters when image resolution procludes comparing bar widths against a standard. It describes several tests used to quarantee the quality of a barcode analyzed on a vision system. The system used in this article is a camera-based system, and the barcodes are read as a series of pixels of varying intensity.

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Barcode Quality Filters

      This article describes a series of tests to insure high quality
reading of barcode characters when image resolution procludes
comparing bar widths against a standard.  It describes several tests
used to quarantee the quality of a barcode analyzed on a vision
system.  The system used in this article is a camera-based system,
and the barcodes are read as a series of pixels of varying intensity.

      A camera-based system can have difficulty applying barcode
specifications to decipher barcodes, such as:

*  Narrow bar width = n pixels

      The camera may not be able to discern narrow white bars and
narrow black bars as being the same width.  This can be caused by a
low number of pixels per bar in the camera image, differing responses
of the camera to black and white transitions (varying saturation of
the pixels), aliasing problems, and the inability of the image to be
threshold precisely.

*  Wide white bar width = m times n pixels where (lower threshold <m
< upper threshold)

      The camera may not be able to discern wide bars as being a
specific multiple of the narrow bar width.  This also can be caused
by a low number of pixels per bar in the camera image, varying
saturation of the pixels, aliasing problems, and the inability of the
image to be threshold precisely.

      In such cases, barcode quality filters must be selected that
reject bad characters without comparing white bar widths with black
bar widths.  Prior to applying these tests, one of sev...