Portable optical reader, optical reading method using the portable optical reader, and computer program

Patent metadata

Field	Value
Publication number	US-9691009-B2
Application number	US-201514679039-A
Country	US
Kind code	B2
Filing date	Apr 6, 2015
Priority date	Apr 23, 2014
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

The present invention provides a portable optical reader, an optical reading method using the portable optical reader and a computer program capable of detecting a high possibility of a reading error and notifying a user of a possibility of a reading error. A character string as a reading target is imaged and a character string is recognized based on the captured image. A plurality of reading formats defining an attribute of the character string is stored, and a first reading format matched with the recognized character string among a plurality of stored reading format is searched. Among the plurality of stored reading formats, a second reading format in which a character string matched with the first reading format as a partial character string is searched. Based on the search result, a possibility of a reading error regarding the recognized character string is notified.

First claim

What is claimed is:

1. A portable optical reader comprising:
imaging unit configured to image a character string as a reading target;
character string recognition unit configured to recognize the character string based on an image captured by the imaging unit;
reading format storage unit configured to store a plurality of reading formats defining an attribute of a character string;
first search processing unit configured to search a first reading format matched with a character string recognized by the character string recognition unit among a plurality of stored reading formats;
second search processing unit configured to search a second reading format in which a character string matched with the first reading format matches as a partial character string among a plurality of stored reading formats; and
notification unit configured to notify a possibility of a reading error regarding the recognized character string based on a search result of the second search processing unit.

2. The portable optical reader according to claim 1 , wherein the notification unit notifies a possibility of a reading error when a matched second reading format is searched in the second search processing unit.

3. The portable optical reader according to claim 1 , further comprising extraction unit configured to extract a highly reliable section of a character string including a partial character sting matched with the first reading format among the recognized character strings,
wherein the second search processing unit searches a second reading format in which a character string matched with the first reading format matches as the partial character string and also is adaptable to a type of characters arranged in the highly reliable section.

4. The portable optical reader according to claim 1 , further comprising:
unit for setting a rectangular area expanded from a character area in an up and down, and left and right directions at a constant ratio every recognized character string;
unit for calculating a ratio of white pixels in a set rectangular area; and
unit for judging based on a calculated ratio whether there is a possibility of a reading error.

5. The portable optical reader according to claim 1 , further comprising:
unit for counting a number of pixels having a brightness value equal to or larger than a predetermined threshold in the character area every recognized character string;
unit for calculating an evaluation value by calculating a ratio of a counted number of pixels to an entire number of pixels; and
unit for judging based on the calculated evaluation value whether there is a possibility of a reading error.

6. The portable optical reader according to claim 1 , further comprising:
unit for extracting a pixel having a brightness value equal to or larger than a predetermined threshold in the character area every character of a recognized character string;
unit for calculating a maximum consecutive number of extracted pixels in a vertical direction or in a lateral direction; and
unit for judging based on the calculated maximum consecutive number whether there is a possibility of a reading error.

7. The portable optical reader according to claim 1 , further comprising:
unit for calculating a distribution histogram of a brightness value about the recognized character area; and
unit for calculating an evaluation value based on the calculated distribution histogram;
unit for judging based on the calculated evaluation value whether there is a possibility of a reading error every character.

8. The portable optical reader,
wherein the unit for judging whether there is a possibility of a reading error calculates an overall evaluation value in which a plurality of evaluation values calculated in the portable optical reader according to claim 5 are integrated, and judges a possibility of a reading error every character based on the overall evaluation value.

9. The portable optical reader according to claim 1 , wherein the notification unit notifies a possibility of a reading error when the first search processing unit searched a plurality of matched first reading formats.

10. The portable optical reader according to claim 1 , further comprising display unit for displaying a read character string and displaying an updatable screen when the notification unit notifies a possibility of a reading error.

11. The portable optical reader according to claim 1 , wherein in the first search processing unit, when no matched first reading format is searched, the notification unit notifies that the imaging unit images again to execute the processing.

12. An optical reading method capable of being executed by a portable optical reader equipped with imaging unit for imaging a character string as a reading target, character string recognition unit for recognizing a character string based on an image captured by the imaging unit, and reading format storage unit for storing a plurality of reading formats defining an attribute of the character string,
wherein the portable optical reader includes:
a first process for searching a first reading format matched with a character string recognized by the character string recognition unit among a plurality of stored reading formats;
a second process for searching a second reading format in which a character string matched with the first reading format among a plurality of stored reading formats matches as a partial character string; and
a third process for notifying a possibility of a reading error regarding the recognized character string based on a search result of the second search processing unit.

13. A computer program stored on a non-transitory computer-readable medium that is executed by a portable optical reader equipped with imaging unit for imaging a character string as a reading target, character string recognition unit for recognizing a character string based on an image captured by the imaging unit, and reading format storage unit for storing a plurality of reading formats defining an attribute of the character string,
wherein the computer program makes the portable optical reader function as
first processing unit for searching a first reading format matched with a character string recognized by the character string recognition unit among a plurality of stored reading formats;
second processing unit for searching a second reading format in which a character string matched with the first reading format among a plurality of stored reading formats matches as a partial character string; and
notification unit for notifying a possibility of a reading error regarding the recognized character string based on a search result of the second search processing unit.

Assignees

• Keyence Co Ltd

Inventors

• Nomi Taiga
• Oki Shusuke

Classifications

• G06V30/127

  with the intervention of an operator · CPC title

• G06V30/274 Primary

  Syntactic or semantic context, e.g. balancing · CPC title

• G06V30/142

  using hand-held instruments; Constructional details of the instruments · CPC title

• G06V30/10

  Character recognition · CPC title

• G06K2209/01

  Physics · mapped topic