Eye image recognition method, eye image selection method and system therefor

• US 6,307,954 B1
• Filed: 02/04/2000
• Issued: 10/23/2001
• Est. Priority Date: 03/26/1997
• Status: Expired due to Fees

• Current Assignee: OKI Electric Industry Company Limited
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: Suzaki, Masahiko
• Primary Examiner(s): MEHTA, BHAVESH M
• Application Number:
  US09/498,484
• Time in Patent Office: 627 Days
• Field of Search: 382/117, 382/118, 382/115-116, 382/286, 382/288, 348/78, 351/204, 351/206, 351/208, 351/211, 351/212
• US Class Current: 382/117
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/20021 Dividing image into blocks, subimages or windows
• CPC Class Codes: G06T 2207/30201 Face
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06T 7/66 of image moments or centre of gravity
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80
• CPC Class Codes: G06V 40/161 Detection; Localisation; Normalisation

Abstract

An input image that includes an eye is divided into a plurality of blocks, and a mosaic image in which each of the blocks has a density value is produced. Among all the blocks, one having a small distance from a center point of the mosaic image and having a small density value is determined to be a block including the center of the pupil of the eye. Then, based on the determined block, a center position of the pupil in the input image is derived. Based on the density value of the block including the center of the pupil, a density threshold value is set. Then, based on the density threshold value, a two-valued image is produced from the input image. Among regions in the two-valued image which are darker than the density threshold value, one including the center position of the pupil is extracted as a pupil region.

Claims

1. An eye image selection method comprising the steps of:

locating a center position of a pupil of an eye from an input image including the eye; and

determining that, if a distance between the center position of said pupil and a center position of said input image is not greater than a preset value, said input image includes necessary eye data for carrying out individual identification, and selecting said input image,

wherein said step of locating a center position of a pupil comprises;

dividing said input image into a plurality of blocks;

producing a mosaic image with said blocks each representing a density value; and

determining that one of said blocks, having a small distance from a center point of said mosaic image and having a small density value, is a block including said center position of said pupil of said eye.

2. The method according to claim 1, wherein said step of locating a center position of a pupil further comprises:

setting a threshold value based on the density value of said determined block;

converting said input image into a two-valued image using said threshold value as a criterion; and

extracting, as a pupil region, a region of said two-valued image including the center position of said pupil.

3. An eye image selection method comprising the steps of:

locating a center position of a pupil of an eye from an input image including the eye; and

determining that, if a distance between the center position of said pupil and a center position of said input image is not greater than a preset value, said input image includes necessary eye data for carrying out individual identification, and selecting said input image,

wherein said steps of locating a center position of a pupil comprises;

dividing said input image into a plurality of blocks;

producing a mosaic image with said blocks each representing a density value;

determining one of said blocks as having a small distance from a center point of said mosaic image and having a small density value; and

locating the center position of said pupil based on said determined block.

4. An eye image selection method comprising the steps of:

locating a center position of a pupil of an eye from an input image including the eye; and

determining that, if a density of a region including said center position is not greater than a given value, said input image includes said pupil for carrying out individual identification, and selecting said input image,

wherein said step of locating a center position of a pupil comprises;

dividing said input image into a plurality of blocks;

producing a mosaic image with said blocks each representing a density value;

determining one of said blocks as having a small distance from a center point of said mosaic image and having a small density value; and

locating the center position of said pupil based on said determined block.

5. An eye image selection method comprising the steps of:

locating a center position of a pupil of an eye from an input image including the eye, said step of locating a center position of a pupil including

dividing an input image including an eye into a plurality of blocks,

producing a mosaic image with said blocks each representing a density value,

determining that one of said blocks, having a small distance from a center point of said mosaic image and having a small density value, is a block including said center position of said pupil, and

locating the center position of said pupil from said determined block; and

selecting said input image for carrying out individual identification if a distance between the center position of said pupil and a center position of said input image is not greater than a preset value and if a density of a region including the center position of said pupil is not greater than a preset value.