Biometric authentication apparatus, biometric authentication method and recording medium

• US 9,070,016 B2
• Filed: 10/11/2013
• Issued: 06/30/2015
• Est. Priority Date: 01/22/2009
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Su, Leiming, Hoshino, Yukio, Itakura, Yukio
• Primary Examiner(s): Koziol, Stephen R
• Assistant Examiner(s): Azima, Shaghayegh
• Application Number:
  US14/052,250
• Publication Number:
  US 20140037153A1
• Time in Patent Office: 627 Days
• Field of Search: 382/117
• US Class Current: 1/1
• CPC Class Codes: A61B 5/117 Identification of persons methods or arrangements for recognising patterns, e.g. fingerprints, G06F18/00, G06V40/00; identification of persons by analysing their voice or speech G10L17/00
• CPC Class Codes: G06V 40/193 Preprocessing; Feature extraction
• CPC Class Codes: G06V 40/197 Matching; Classification
• CPC Class Codes: G07C 9/37 using biometric data, e.g. fingerprints, iris scans or voice recognition

Abstract

A plurality of pieces of information related to the iris pattern of an eye can be checked against each other in a short time. Characteristic curves (S(1)-S(8)), which are in accordance with eight ring areas (A1-A8) formed by dividing an image of an iris, are generated. The polarities of the gradients of these characteristic curves are then arranged, thereby generating codes (1-8) to be checked. Each of these codes (1-8) to be checked consists of a ternary combination of +, − and zero, whereby the amount of data to be handled during the checking process can be reduced. As a result, checking the codes to be checked can be performed in a short time.

Claims

1. A biometric authentication apparatus, comprising:

a curve calculating unit which is implemented in a processor and which is configured for calculating, based on a digital image of an iris, curves showing a relationship between polar coordinates indicating a position of the iris on the digital image and luminance of pixels of the digital image of the iris corresponding to coordinate values of the polar coordinates; and

a code generating unit which is implemented in a processor and which is configured for generating a comparison target code by arranging three values based on polarities of slopes of the curves in order of the polar coordinates, wherein the three values include +, −

, and 0.

2. The biometric authentication apparatus according to claim 1, wherein the curve calculating unit possesses:

a first partitioning unit which is implemented in a processor and which is configured for partitioning the digital image of the iris into multiple annular regions;

a second partitioning unit which is implemented in a processor and which is configured for partitioning each of the annular regions into multiple microregions corresponding to a polar coordinate having an origin that is a center of a circle defining the inside edge of the annular region;

a computing unit which is implemented in a processor and which is configured for calculating the average value of the luminance of the pixels contained in the microregions for each annular region; and

a generating unit which is implemented in a processor and which is configured for generating, for each of the annular regions, a curve showing the relationship between the polar coordinate having the origin that is the center of the circle defining the inside edge for the annular region and the average value of the luminance in the microregions for the annular region.

3. The biometric authentication apparatus according to claim 1, wherein the polarities of the slopes of the curve are each one of the three values consists of a positive value, a negative value, and zero.

4. A biometric authentication method, comprising:

a process for calculating, based on a digital image of an iris, curves showing a relationship between polar coordinates indicating a position of the iris on the digital image and luminances of pixels comprising of digital image of the iris corresponding to coordinate values of the polar coordinates; and

a process for generating a comparison target code by arranging three values based on polarities of slopes of the curves in order of the polar coordinates, wherein the three values include +, −

, and 0.

5. A non-transitory computer-readable recording medium on which is recorded a program that causes a computer to function as:

a means for calculating, based on a digital image of an iris, curves showing a relationship between polar coordinates indicating a position of the iris on the digital image and luminances of pixels of the digital image of the iris corresponding to coordinate values of the polar coordinates; and

a means for generating a comparison target code by arranging three values based on polarities of slopes of the curves in order of the polar coordinates, wherein the three values include +, −

, and 0.