Optical information reading apparatus

• US 5,550,363 A
• Filed: 02/24/1994
• Issued: 08/27/1996
• Est. Priority Date: 02/25/1993
• Status: Expired due to Fees

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Obata, Kenzo
• Primary Examiner(s): PITTS, HAROLD I
• Application Number:
  US08/202,183
• Time in Patent Office: 915 Days
• Field of Search: 235/462, 235/487, 235/494
• US Class Current: 235/462.11
• CPC Class Codes: G06K 7/1093 sensing, after transfer of the image of the data-field to an intermediate store, e.g. storage with cathode ray tube

Abstract

An optical information reading apparatus includes a two-dimensional image pickup apparatus having a number of photoelectric conversion elements arranged in a plane for capturing an image of optical information on a read object. The optical information reading apparatus detects a bar code contained in the captured information image and derives an area of each of bars and spaces of the bar code in the captured information image. The optical information reading apparatus recognizes and decodes the bar code using a ratio of the derived areas of the bars and the spaces of the bar code.

Claims

1. An optical information reading apparatus comprising:

a light source for emitting light onto an object bearing optical information;

an optical system for collecting said light reflected by said object so as to form an information image indicative of said optical information at a predetermined reading position;

two-dimensional image pickup means having a plurality of photoelectric conversion elements arranged in a plane, said two-dimensional image pickup means being provided at said predetermined reading position for capturing said information image;

storing means for storing said information image captured by said two-dimensional image pickup means;

two-dimensional information decoding means for recognizing two-dimensional information in said information image stored by said storing means;

region detecting means for detecting a region of each bar and a region of each space of a bar code in said information image stored by said storing means, said bars and said spaces being alternately arranged to form said bar code; and

bar code decoding means for decoding said bar code based on a relationship between areas of said regions of said bars and areas of said regions of said spaces detected by said region detecting means.

2. The optical information reading apparatus as set forth in claim 1, wherein said two-dimensional information decoding means includes character decoding means for recognizing and decoding a character in said information image stored in said storing means so as to decode said recognized character.

3. The optical information reading apparatus as set forth in claim 1, wherein said two-dimensional information decoding means includes two-dimensional code decoding means for recognizing a two-dimensional code in said information image stored by said storing means so as to decode said recognized two-dimensional code, said two-dimensional code having high reflectance cells and low reflectance cells arranged in a given matrix.

4. The optical information reading apparatus as set forth in claim 2, wherein said character decoding means comprises:

character pattern storing means for prestoring basic patterns of characters to be decoded;

character matching means for reading out said information image from said storing means and for comparing in sequence a pattern of a character contained in said information image with said basic character patterns prestored by said character pattern storing means so as to derive matching degrees therebetween, respectively;

pattern switching means, in response to a character pattern changing command which is output from said matching means every time said matching means performs said pattern comparison, for changing in sequence said basic character pattern to be output from said character pattern storing means to said matching determining means; and

selecting means for selecting one of said basic character patterns having a highest matching degree derived by said matching means.

5. The optical information reading apparatus as set forth in claim 3, wherein said two-dimensional code decoding means comprises:

position determining means for reading out said information image from said storing means and for determining a position of a perimeter portion of said two-dimensional code contained in said information image;

data density deriving means for deriving a data density of said two-dimensional code based on said high reflectance cells and said low reflectance cells arranged at said perimeter portion;

cell position deriving means for deriving a position of each of said cells in said matrix based on said data density derived by said data density deriving means; and

decoding means for determining a reflectance at each of said cell positions derived by said cell position deriving means so as to identify an arrangement of said high reflectance cells and said low reflectance cells and for decoding said two-dimensional code based on said identified cell arrangement.

6. The optical information reading apparatus as set forth in claim 1, wherein said region detecting means comprises:

region data detecting means for reading out said information image from said storing means and for detecting region data corresponding to each of said bars and said spaces in each horizontal line of said information image;

region data storing means for storing said region data detected by said region data detecting means; and

counting means for counting picture elements contained in said region data stored by said region data storing means so as to derive a total number of said picture elements forming each of said bars and said spaces in said information image.

7. The optical information reading apparatus as set forth in claim 6, wherein said region detecting means includes region data storage determining means for determining whether said region data in all of said horizontal lines are stored by said region data storing means, and wherein said counting means is operated when said region data storage determining means determines that said region data in all of said horizontal lines are stored by said region data storing means.

8. The optical information reading apparatus as set forth in claim 6, wherein said region detecting means includes region data storage determining means for determining whether said region data in all of said horizontal lines are stored by said region data storing means, and wherein said region data detecting means continues to detect said region data when said region data storage determining means determines that said region data in all of said horizontal lines are not stored by said region data storing means.

9. The optical information reading apparatus as set forth in claim 6, wherein said region data includes binary information indicative of said bar or said space, a picture element number information indicative of a number of said picture elements forming a corresponding one of said bars and said spaces in corresponding one of said horizontal lines, and positional information indicative of position of said region data in said information image.

10. The optical information reading apparatus as set forth in claim 9, wherein said positional information includes a variable which changes when said binary information is changed in a corresponding horizontal line, and horizontal line position information indicative of a position of said corresponding horizontal line in a vertical direction in said information image.

11. The optical information reading apparatus as set forth in claim 1, further comprising selecting means for selectively activating one of said two-dimensional information decoding means and said bar code decoding means and for outputting a decoding result of the activated decoding means.

12. The optical information reading apparatus as set forth in claim 1, further comprising selecting means for simultaneously activating said two-dimensional information decoding means and said bar code decoding means and for outputting one of decoding results of said two-dimensional information decoding means and said bar code decoding means based on said decoding results.

25. The optical information reading apparatus as set forth in claim 1, wherein said bar code decoding means decodes said bar code based on a ratio between said areas of said regions of said bars and said areas of said regions of said spaces detected by said region detecting means.

27. The optical information reading apparatus as set forth in claim 1, wherein said bar code decoding means decodes said bar code information based on a ratio between said two-dimensional areas of said bars and said two-dimensional areas of said spaces detected by said area detecting means.

13. An optical information reading apparatus comprising:

a light source for emitting light onto an object bearing optical information;

an optical system for collecting said light reflected by said read object so as to form an information image indicative of said optical information at a predetermined reading position;

two-dimensional image pickup means having a plurality of photoelectric conversion elements arranged in a plane, said two-dimensional image pickup means being provided at said predetermined reading position for capturing said information image;

storing means for storing said information image captured by said two-dimensional image pickup means;

two-dimensional information decoding means for recognizing two-dimensional information in said information image stored by said storing means;

area deriving means for detecting a bar code contained in said information image stored by said storing means, said bar code having a bar and a space, and for determining an area of each bar and each space of said bar code included in said information image stored by said storing means; and

bar code decoding means for decoding said bar code based on a relationship between areas of said bars and areas of said spaces detected by said area deriving means.

26. The optical information reading apparatus as set forth in claim 13, wherein said bar code decoding means decodes said bar code based on a ratio between said areas of said bars and said areas of said spaces detected by said area deriving means.

14. An optical information reading apparatus comprising:

a light source for emitting light onto an object bearing optical information;

an optical system for collecting said light reflected by said object so as to form an image indicative of said optical information at a predetermined reading position;

two-dimensional image pickup means having a plurality of photoelectric conversion elements arranged in a same plane, said two-dimensional image pickup means provided at said predetermined reading position for capturing said image indicative of said optical information;

storing means for storing said image captured by said two-dimensional image pickup means;

two-dimensional information decoding means for recognizing two-dimensional information in said image stored by said storing means; and

area detecting means for detecting a two-dimensional area of each bar and a two-dimensional area of each space in said bar code information included in said image stored by said storing means, and

bar code decoding means for decoding said bar code information based on a relationship between said two-dimensional areas of said bars and said two-dimensional areas of said spaces detected by said area detecting means.

15. The optical information reading apparatus as set forth in claim 14, wherein said two-dimensional information decoding means includes character decoding means for recognizing and decoding a character in said information image stored in said storing means.

16. The optical information reading apparatus as set forth in claim 14, wherein said two-dimensional information decoding means includes two-dimensional code decoding means for recognizing and decoding a two-dimensional code in said information image stored by said storing means, said two-dimensional code having a plurality of high reflectance cells and a plurality of low reflectance cells arranged in a matrix.

17. The optical information reading apparatus as set forth in claim 15, wherein said character decoding means comprises:

character pattern storing means for storing patterns of characters;

character matching means for reading out said image from said storing means, sequentially comparing a pattern of a character contained in said image to said character patterns stored in said character pattern storing means, and determining matching degrees between said character contained in said image and said character patterns stored in said character pattern storing means;

pattern switching means, in response to said matching means when said matching means compares said character contained in said image and said character patterns stored in said character pattern storing means, for sequentially changing said character pattern output from said character pattern storing means to said matching determining means; and

selecting means for selecting one of said character patterns having a highest matching degree derived by said matching means.

18. The optical information reading apparatus as set forth in claim 16, wherein said two-dimensional code decoding means comprises:

position determining means for reading out said image from said storing means and for determining a position of a perimeter portion of said two-dimensional code contained in said image;

data density deriving means for deriving a data density of said two-dimensional code based on said plurality of high reflectance cells and said plurality of low reflectance cells arranged at said perimeter portion;

cell position deriving means for deriving a position of each of said cells in said matrix based on said data density derived by said data density deriving means; and

decoding means for determining a reflectance at each of said cell positions derived by said cell position deriving means so as to identify an arrangement of said plurality of high reflectance cells and said plurality of low reflectance cells and for decoding said two-dimensional code based on said identified cell arrangement.

19. The optical information reading apparatus as set forth in claim 14, wherein said area detecting means comprises:

data detecting means for reading out said image from said storing means and for detecting data corresponding to each of said bars and said spaces in each of a plurality of horizontal lines of said image;

data storing means for storing said data detected by said region data detecting means; and

counting means for counting picture elements contained in said data stored by said data storing means so as to derive a total number of said picture elements forming each of said bars and said spaces in said information image.

20. The optical information reading apparatus as set forth in claim 19, wherein said area detecting means includes data storage determining means for determining whether said data in all of said plurality of horizontal lines are stored by said data storing means, and wherein said counting means is operated when said data storage determining means determines that said data in all of said plurality of horizontal lines are stored by said data storing means.

21. The optical information reading apparatus as set forth in claim 19, wherein said area detecting means includes data storage determining means for determining whether said data in all of said plurality of horizontal lines are stored by said data storing means, and wherein said data detecting means continues to detect said data corresponding to each of said bars and said spaces when said data storage determining means determines that said data in all of said plurality of horizontal lines has not been stored by said region data storing means.

22. The optical information reading apparatus as set forth in claim 19, wherein said data includes binary information indicative of a presence of one of said bar or and said space, picture element number information indicative of a number of picture elements forming a corresponding one of said bars and said spaces in corresponding one of said plurality of horizontal lines, and positional information indicative of position of said data in said image.

23. The optical information reading apparatus as set forth in claim 22, wherein said positional information includes a variable which changes when said binary information is changed in a corresponding horizontal line, and horizontal line position information indicative of a position of said corresponding horizontal line in a vertical direction in said information image.

24. The optical information reading apparatus as set forth in claim 14, further comprising selecting means for simultaneously activating said two-dimensional information decoding means and said bar code decoding means.