Extended working range dataform reader with reduced power consumption

• US 5,811,774 A
• Filed: 08/15/1996
• Issued: 09/22/1998
• Est. Priority Date: 07/26/1994
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Original Assignee: Metanetics Corporation
• Inventors: Wang, Ynjiun P., Ju, Paul P.
• Primary Examiner(s): Pitts, Harold
• Assistant Examiner(s): TREMBLAY, MARK STEPHEN
• Application Number:
  US08/698,428
• Time in Patent Office: 768 Days
• Field of Search: 235/455, 235/472
• US Class Current: 235/455
• CPC Class Codes: G01J 3/0272 Handheld
• CPC Class Codes: G01J 3/10 Arrangements of light sources specially adapted for spectrometry or colorimetry
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/51 using colour filters
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G06K 2007/10524 Hand-held scanners
• CPC Class Codes: G06K 2207/1011 Aiming
• CPC Class Codes: G06K 7/10564 Light sources
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10752 Exposure time control
• CPC Class Codes: G06K 7/10792 Special measures in relation to the object to be scanned
• 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 7/10881 constructional details of hand-held scanners
• CPC Class Codes: G06K 7/10891 the scanner to be worn on a finger or on a wrist
• CPC Class Codes: G06K 7/1092 sensing by means of TV-scanning

Abstract

An extended working range dataform reader with reduced power consumption having a camera assembly and a circuit control board including game control circuitry and exposure control circuitry configured to set an initial gain value and an initial exposure period, respectively, resulting from a previous dataform reading session. Subsequent fields of image data are captured by the camera which are used to correct the gain and exposure relative to the initial values for gain and exposure period, thereby reducing the latency period for realizing correct values and reducing power consumption during power up. Furthermore, the gain control system and the exposure control system each utilize an open loop feedback such that successive fields of image data captured by the camera are utilized to calculate correct values, thereby reducing the latency time for realizing a correct value. Additionally, a reader module is provide for use in a dataform reader that emulates a laser module such that the dataform reader module can be readily integrated into existing laser-based dataform reading systems. Preferably, laser model emulation circuitry included in the dataform reader module emulates output of a laser scan module and a control circuit board in which the emulation circuitry is realized has an output port constructed and arranged to communicate with devices configured for use with a laser scanner.

Claims

1. A two dimensional imaging based dataform reader module for use in a dataform reader, the reader module comprising:

a) an illumination module directing illumination towards a target area and including targeting illuminators and exposure illuminators;

b) a camera module including a photosensor array generating a signal representative of an image of the target area;

c) control circuitry to selectively energize the illumination module and the camera module during a dataform reading session and to turn off the illumination module and camera module upon completion of the dataform reading session, the dataform reading session including a targeting state and a dataform read state, the dataform read state including an exposure substate and a decode substate;

d) the control circuitry, during the targeting state, energizing the targeting illuminators and turning off the exposure illuminators and the camera module;

e) the control circuitry, during the exposure substate of the dataform read state, energizing the exposure illuminators and the camera module and turning off the targeting illuminators; and

f) the control circuitry, during the decode substate of the dataform read state, energizing the targeting illuminators and turning off the exposure illuminators and the camera module.