Method and apparatus for reading one-and two-dimensional symbols with a linear detector

• US 5,912,452 A
• Filed: 02/06/1997
• Issued: 06/15/1999
• Est. Priority Date: 02/06/1997
• Status: Expired due to Term

• Current Assignee: Intermec IP Corporation (Honeywell International Inc.)
• Original Assignee: Intermec Corporation (Honeywell International Inc.)
• Inventors: Wiklof, Christopher A., Ackley, H. Sprague
• Primary Examiner(s): Hajec, Donald
• Assistant Examiner(s): Lee, Diane I.
• Application Number:
  US08/795,590
• Time in Patent Office: 859 Days
• Field of Search: 235/472.01, 235/462.1, 235/454, 235/463, 235/470, 235/440, 235/456, 235/462.11, 235/462.32
• US Class Current: 235/472.01
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence

Abstract

A symbology reader uses a linear detector to image a two-dimensional area by scanning the field of view of the linear detector across an image field. In one embodiment, the reader simultaneously decodes data from the linear detector according to two-dimensional techniques and linear and stacked symbology techniques. If the reader identifies a linear or stacked symbology, the two-dimensional processing is interrupted. As the reader scans the field of view of the linear detector across the image field, the scanning mirror simultaneously sweeps a light plane across the image field so that only the imaged region is illuminated, thereby improving the dynamic range of the reader.

Claims

1. A method of imaging a two-dimensional image field, comprising:

illuminating the two-dimensional image field with light, the light being substantially fixed relative to the two-dimensional image field during the imaging;

providing a linear detector having a field of view along an optic axis;

aligning the field of view to an initial linear region of the image field;

substantially simultaneously imaging the initial linear region to produce a first image portion while the field of view is substantially in a single position;

pivoting the optic axis a selected increment to align the field of view to a subsequent linear region of the image field;

substantially simultaneously imaging the subsequent linear region to produce a subsequent image portion;

repeatedly pivoting the optic axis a selected increment to align the field of view to a subsequent region and imaging the subsequent region to produce a subsequent image portion until the optic axis has pivoted through a selected angular range; and

before completing the repeated pivoting and imaging, performing a decode operation according to linear or stacked symbology decoding techniques; and

if the decode operation does not identify a linear or stacked symbology, performing a decode operation according to two-dimensional symbology techniques.

2. A method of imaging a two-dimensional image field, comprising:

illuminating the two-dimensional image field with light, the light being substantially fixed relative to the two-dimensional image field during the imaging;

providing a linear detector having a field of view along an optic axis;

aligning the field of view to an initial linear region of the image field;

substantially simultaneously imaging the initial linear region to produce a first image portion while the field of view is substantially in a single position;

pivoting the optic axis a selected increment to align the field of view to a subsequent linear region of the image field;

substantially simultaneously imaging the subsequent linear region to produce a subsequent image portion;

repeatedly pivoting the optic axis a selected increment to align the field of view to a subsequent region and imaging the subsequent region to produce a subsequent image portion until the optic axis has pivoted through a selected angular range; and

before completing the repeated pivoting and imaging, performing a decode operation according to linear or stacked symbology decoding techniques by beginning the decode operation according to two-dimensional symbology techniques; and

if the linear decode operation identifies a linear or stacked symbology, interrupting the two-dimensional symbology decode operation.

3. A symbology reading system comprising:

a light emitter having a beam pattern along an optic axis with a substantially linear cross-section;

a first linear array having a substantially linear field of view, the first linear array being operational to produce electrical signals indicative of light energy in respective regions of the field of view;

an optical assembly aligned to the field of view and the optic axis and including an electronically controlled beam steering assembly, the beam steering assembly being alignable to simultaneously sweep the beam pattern and translate the field of view through a plurality of positions;

a memory array including a plurality of memory locations;

an electronic controller coupled to the linear array and the memory array to store in the memory array data representative of the electrical signals indicative of the light energy in the respective regions of the field of view; and

a second linear array positioned to detect a portion of the beam pattern to provide an indication of elevation of the beam pattern.

4. The symbology reading system of claim 3 wherein the second linear array is mounted transversely to the optic axis and a line defined by the linear cross-section.