Registers – Coded record sensors – Particular sensor structure
Reexamination Certificate
2000-01-04
2001-11-20
Frech, Karl D. (Department: 2876)
Registers
Coded record sensors
Particular sensor structure
C235S462240
Reexamination Certificate
active
06318637
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a portable data collection device including an imaging based dataform reader and, more particularly, to a portable data collection device including an imaging based dataform reader utilizing multiple focal lengths to capture and identify an imaged dataform.
BACKGROUND OF THE INVENTION
Portable data collection devices are widely used in manufacturing, service and package delivery industries to perform a variety of on-site data collection activities. Such portable data collection devices often include integrated bar code dataform readers adapted to read bar code dataforms affixed to products, product packaging and/or containers in warehouses, retail stores, shipping terminals, etc. for inventory control, tracking, production control and expediting, quality assurance and other purposes. Various bar code dataform readers have been proposed for portable data collection devices including laser scanners and one dimensional (1D) charge coupled device (CCD) imaging assemblies, both of which are capable of reading 1D bar code dataforms, that is, bar codes consisting of a single row of contrasting black bars and white spaces of varying widths. Both laser scanners and CCD imaging assemblies are also capable of reading a “stacked” two dimensional (2D) bar code dataforms, such as PDF417, which is comprised of a plurality of adjacent rows of bar code data. The stacked 2D bar code PDF417 includes row indicator patterns utilized by the dataform reader for vertical synchronization to permit reading successive rows of bar code data.
A two dimensional (2D) imaging based dataform reader has been proposed in U.S. application Ser. No. 08/544,618, filed Oct. 18, 1995, now issued as U.S. Pat. No. 5,702,059 and entitled “Extended Working Range Dataform Reader Including Fuzzy Logic Image Control Circuitry”. The 2D dataform reader disclosed in application Ser. No. 08/544,618, which is assigned to the assignee of the present application, includes an imaging assembly having a two dimensional array of photosensors adapted to read 2D bar code dataforms (e.g., PDF417, SuperCode, etc.) with vertical synchronization row indicator patterns as well as matrix dataforms (e.g., MaxiCode, DataMatrix, etc.) which do not include vertical synchronization patterns. The individual photosensors correspond to image picture elements or pixels of the resulting image generated with the photosensors are read out after an exposure period or periods. The 2D dataform reader disclosed in application Ser. No. 08/544,618 utilizes an open loop feedback control system including fuzzy logic circuitry to determine proper exposure time and gain parameters for a camera assembly. Application Ser. No. 08/544,618 is incorporated in its entirety herein by reference.
A problem associated with dataform readers in the past has been that the readers are designed to read dataforms located within a limited range from the reader. For example, a dataform reader may be designed to read dataforms located within the range of 3 inches to 12 inches from the reader. Unfortunately, oftentimes it is necessary to read a dataform which is located a greater distance away (e.g., several feet away). However, the dataform reader is unable to image the dataform satisfactorily at such range. This requires that the operator gain closer access to the dataform which at times can be inconvenient or impossible. As an example, in a warehouse an operator may have to utilize a ladder or lift in order to get close enough to a dataform on a shelf so that the dataform may be read.
In view of the aforementioned shortcomings associated with conventional dataform readers, there is a strong need in the art for a dataform reader which is capable of reading dataforms over a wider range of distances. In particular, there is a strong need for a dataform reader which quickly and accurately captures and identifies an imaged dataform at relatively low cost.
SUMMARY OF THE INVENTION
According to one aspect of the invention, a dataform reader is provided for reading a dataform. The dataform reader includes a hand-portable sized housing; an image assembly included within the housing, the image assembly including means for obtaining a plurality of sets of image data representing the dataform when positioned a given distance from the dataform, each of the plurality of sets of image data being obtained relative to a different respective best focus length from the image assembly; and means within the housing for selecting, from among the plurality of sets of image data, image data satisfying a predefined focus criteria.
According to another aspect of the invention, a method is provided for reading a dataform using a portable dataform reader. The method includes the steps of obtaining a plurality of sets of image data of the dataform when the portable dataform reader is positioned a given distance from the dataform, each of the plurality of sets of image data being obtained relative to a different respective best focus length from the image assembly; and selecting, from among the plurality of sets of image data, image data satisfying a predefined focus criteria.
These and other aspects, features and advantages of the invention will become better understood from the detailed description of the preferred embodiments of the invention which are described in conjunction with the accompanying drawings.
REFERENCES:
patent: 4831275 (1989-05-01), Drucker
patent: 4843222 (1989-06-01), Hochgraf
patent: 4877949 (1989-10-01), Danielson et al.
patent: 5071207 (1991-12-01), Ceglio et al.
patent: 5198648 (1993-03-01), Hibbard
patent: 5308966 (1994-05-01), Danielson et al.
patent: 5325217 (1994-06-01), Nagler et al.
patent: 5563658 (1996-10-01), Parulski et al.
patent: 5576529 (1996-11-01), Koenck et al.
patent: 5627366 (1997-05-01), Katz
patent: 5640001 (1997-06-01), Danielson et al.
patent: 5710416 (1998-01-01), Belknap et al.
patent: 5777308 (1998-07-01), Shimizu et al.
patent: 5796089 (1998-08-01), Marom
patent: 5814803 (1998-09-01), Olmstead et al.
patent: 5818023 (1998-10-01), Meyerson et al.
patent: 5914478 (1999-06-01), Bridgelall
patent: 5969325 (1999-10-01), Hecht et al.
patent: 5988504 (1999-11-01), Smitt
patent: 6053408 (2000-04-01), Stoner
patent: 6123261 (2000-09-01), Roustaei
patent: 6152368 (2000-11-01), Olmstead et al.
patent: 6170749 (2001-01-01), Goren et al.
patent: 2 683 109 (1993-04-01), None
patent: 52-44653 (1977-04-01), None
patent: 62-34114 (1987-02-01), None
Amin & Turocy LLP
Frech Karl D.
Fureman Jared J.
Telxon Corporation
LandOfFree
Multi-focal length imaging based portable dataform reader does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multi-focal length imaging based portable dataform reader, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multi-focal length imaging based portable dataform reader will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2585020