Non-decoded type bar code reading apparatus

• US 5,184,005 A
• Filed: 01/07/1991
• Issued: 02/02/1993
• Est. Priority Date: 01/08/1990
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Mori, Koji, Ukai, Naoki
• Primary Examiner(s): PITTS, HAROLD I
• Application Number:
  US07/637,706
• Time in Patent Office: 757 Days
• Field of Search: 235/462, 235/463, 235/472
• US Class Current: 235/462.16
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners
• CPC Class Codes: Y10S 235/901 Bar code reader specialized to read code on a highly reflective surface

Abstract

A bar code reading apparatus for optically reading a bar code comprising bars and spaces successively and alternately arranged to output a digital signal to a decoder placed at the reading apparatus. The reading apparatus includes a conversion circuit for converting the bar code information into a digital signal having high-level and low-level portions with time periods corresponding to the widths of the bars and spaces. Also included in the reading apparatus is a preprocessing unit for converting the digital signal into width data to correct the width data so as to narrow the scattering of the width data. The preprocessing unit reproduces a digital signal on the basis of the corrected width data, which is in turn supplied as the bar code information to the decoder. With this arrangement, the decoder can easily and surely decode the inputted bar code information.

Claims

1. A bar code reading apparatus for optically reading a bar code to output as bar code information a digital signal indicating widths of successively alternately arranged bars and spaces of said bar code with its high-level durations and low-level separations to a decoder for decoding said digital signal indicative of said bar code information, said apparatus comprising:

a hand-operable housing;

producing means for producing an image of said bar code within said housing;

sensor means encased in said housing and equipped with a plurality of picture elements one-dimensionally arranged, for converting said image of said bar code into an electric signal at every picture element and for successively outputting said electric signals corresponding to said bar code;

signal processing means provided in said housing for smoothing said electric signal output from said sensor means at every picture element and for converting said electric signals into a digital signal, said digital signal having alternate high-level portions and low-level portions, said portions having time periods corresponding to said widths of said bars and spaces of said bar code;

width data producing means encased in said housing and responsive to said digital signal from said signal processing means, for producing a plurality of width data indicating said widths of said bars and spaces of said bar code on the basis of said high-level time periods and low-level time periods of said digital signal from said signal processing means;

memory means encased in said housing for successively storing said plurality of width data produced by said width data producing means;

classifying means encased in said housing for classifying said plurality of width data stored in said memory means into a plurality of groups;

correction means encased in said housing for correcting said plurality of width data so as to narrow scattering of said width data in each of said groups classified by said classifying means and for outputting corrected width data;

digital signal reproducing means encased in said housing for reproducing a digital signal having alternate high-level portions and low-level portions, said portions having time periods corresponding to said corrected width data output by said correction means; and

signal outputting means encased in said housing for outputting said digital signal reproduced by said reproducing means to decoder located external to said housing.

2. An apparatus as claimed in claim 1, wherein said signal processing means is a signal processing circuit encased in said housing to smooth said electric signals output from said sensor means at every picture element and to convert said smoothed electric signals into a digital signal with high-levels and low-levels which are alternately and successively switched.

3. An apparatus as claimed in claim 1, wherein said width data producing means, said classifying means, said correction means and said digital signal reproducing means are realized by operations of a microcomputer coupled to said memory means.

4. An apparatus as claimed in claim 1, wherein said correction means corrects said plurality of width data in each of said plurality of groups to one or more representative values.

5. An apparatus as claimed in claim 1, wherein said correction means corrects said plurality of width data in each of said plurality of groups to a central value of the corresponding group.

6. An apparatus as claimed in claim 1, wherein said classifying means classifies said plurality of width data into a first group including relatively narrow width data and a second group including relatively wide width data.

7. An apparatus as claimed in claim 6, wherein said correction means detects a first width indicative of a widest width in said first group and a second width indicative of a narrowest width in said second group and corrects said first and second width so as to enlarge a separation therebetween.

14. An apparatus as claimed in claim 1, wherein said sensor means comprises a CCD-type image sensor.

15. An apparatus as claimed in claim 1, wherein said sensor means comprises a MOS-type image sensor.

16. An apparatus as claimed in claim 1, wherein said producing means comprises an LED.

17. An apparatus as claimed in claim 1, wherein said producing means comprises an incandescent lamp.

18. An apparatus as claimed in claim 1, wherein said producing means comprises a laser.

19. An apparatus as claimed in claim 1, wherein said producing means comprises a mirror and a lens.

8. A bar code reading apparatus for optically reading a bar code to output as bar code information a digital signal indicating widths of successive alternately arranged bars and spaces of said bar code by high-level durations and low-level separations to a decoder for decoding said digital signal indicative of the bar code information, said apparatus comprising:

a hand-operable housing;

conversion means encased in said housing for optically detecting said bar code and outputting a digital signal, said digital signal having alternate high-level portions and low-level portions, said portions having time periods corresponding to said widths of said bars and spaces of said bar code; and

preprocessing means encased in said housing for correcting said high-level time periods and low-level time periods of said digital signal so as to narrow scattering of a distribution of said widths of said bars and spaces indicated by said high-level time periods and low-level time periods and for producing a corrected digital signal which is in turn supplied to said decoder located external to said housing.

9. An apparatus as claimed in claim 8, wherein said preprocessing means corrects said high-level time periods and low-level time periods of said digital signal so as to narrow scattering of said distribution of said widths of said bars and spaces in each of a plurality of groups, said groups being formed by classifying data indicative of said bar code.

10. An apparatus as claimed in claim 9, wherein said preprocessing means corrects said high-level time periods and low-level time periods of said digital signal so as to narrow scattering of said distribution at every group of widths of said bars and spaces of said bar code.

11. An apparatus as claimed in claim 9, wherein said preprocessing means corrects said high-level time periods and low-level time periods of said digital signal so as to enlarge a separation between a widest width in a first group including relatively narrow widths and a narrowest width in a second group including relatively wide widths.

12. A bar code reading apparatus for outputting an electric signal indicative of widths of bars and spaces of a bar code to a decoder for decoding bar code information by distinguishing ranges of said widths of said bars and spaces of said bar code, said apparatus comprising:

a hand-operable housing;

conversion means encased in said housing for optically detecting said bar code and converting said optically detected bar code into an electric signal in correspondence with said widths of said bars and spaces thereof; and

preprocessing means encased in said housing for correcting said electric signal from said conversion means to distinguish said ranges of said widths of said bars and spaces and for outputting a corrected electric signal to said decoder located external to said housing.

13. An apparatus as claimed in claim 12, wherein said preprocessing means corrects said electric signal so as to enlarge a separation between a widest width in a first group including relatively narrow widths and a narrowest width in a second group including relatively wide widths.