Authentication object image-pickup method and device therefor

• US 7,181,049 B2
• Filed: 04/26/2002
• Issued: 02/20/2007
• Est. Priority Date: 05/11/2001
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Ike, Takahiro
• Primary Examiner(s): Mancuso; Joseph
• Assistant Examiner(s): DULANEY, KATHLEEN YUAN
• Application Number:
  US10/332,783
• Publication Number:
  US 20030108224A1
• Time in Patent Office: 1,761 Days
• Field of Search: 382/117, 348/354
• US Class Current: 382/117
• CPC Class Codes: A61B 3/1216 for diagnostics of the iris
• CPC Class Codes: A61B 5/1171 based on the shapes or appearances of their bodies or parts thereof
• CPC Class Codes: G02B 7/36 using image sharpness techniques , e.g. image processing techniques for generating autofocus signals image data processing per se G06T; in cameras having a solid state image sensor H04N23/67
• CPC Class Codes: G06V 40/19 Sensors therefor

Abstract

In an iris image pickup method in which an image signal picking up an iris is allowed to pass through a high-pass filter (41L) and a lens position in which an output of the high-pass filter (41L) indicates a peak value is searched by a mountaineering method, thereby capturing an iris image focused on the iris, when an amount of a high luminance component included in the image signal is equal to or greater than a predetermined value, a peak position of a high frequency component in the image signal passing through a narrow-band high-pass filter (41H) for causing only a high band in a pass band of the high-pass filter (41L) to pass therethrough is obtained by searching for a whole area within a predetermined range in place of a search for a focusing position by the mountaineering method, and is set to be an iris focusing position. Consequently, it is possible to acquire a clear iris image having a high authentication rate which is focused on the iris in place of glasses. Also in the case in which an authentication object person wears the glasses, consequently, an image focused on the iris can be acquired.

Claims

1. An authentication object image pickup method comprising:

allowing an image signal obtained by picking up an authentication object to pass through a filter;

searching a lens position in which an output of the filter indicates a peak value by a mountaineering method;

searching a peak position of a high frequency component in the image signal obtained by searching for a whole area within a predetermined range;

capturing an image focused on the authentication object;

determining whether an amount of a high luminance component included in the image signal is equal to or greater than a predetermined value;

switching between the searching process of the peak position of the high frequency component and the searching process by the mountaineering method based on a result of the determining process; and

setting the peak position or a focusing position corresponding to the lens position to an authentication object focusing position.

2. The authentication object image pickup method according to claim 1, wherein the filter is a narrow-band high-pass filter for allowing only a high band of a frequency component in the image signal to pass therethrough.

3. The authentication object image pickup method according to claim 1, wherein the predetermined range is determined by a distance to the authentication object measured by ranging means.

4. The authentication object image pickup method according to claim 3, wherein the predetermined range is set to be a range of the measured distance ±

20% around the measured distance.

5. The authentication object image pickup method according to any of claims 1 to 4, wherein when the amount of the high luminance component included in the image signal is equal to or greater than the predetermined value, an illuminating direction for the authentication object is switched to capture the image signal.

6. The authentication object image pickup method according to claim 5, wherein when the amount of the high luminance component is not smaller than the predetermined value even if the illuminating direction for the authentication object is switched, the authentication object is illuminated in such an illuminating direction that the high luminance component is the smallest, thereby carrying out a processing of searching for the authentication object focusing position.

13. The authentication object image pickup method according to claim 1, further comprising the step of performing the searching process of the peak position of the high frequency component when the amount of the high luminance component included in the image signal is equal to or greater than the predetermined value.

7. An authentication object image pickup apparatus comprising:

image pickup means for picking up an image of an authentication object;

a filter for allowing an image signal captured by the image pickup means to pass therethrough;

control means for allowing the image pickup means to capture an image focused on the authentication object;

means for searching for a lens position in which an output of the filter indicates a peak value by a mountaineering method;

means for searching for a whole area within a predetermined range to obtain a peak position of a high frequency component in the image signal;

determining means for determining whether an amount of a high luminance component included in the image signal is equal to or greater than a predetermined value;

switching means for switching between the searching process of the peak position of the high frequency component and the searching process by the mountaineering method based on a result of the determining process; and

setting means for setting the peak position or a focusing position corresponding to the lens position to an authentication object focusing position.

8. The authentication object image pickup apparatus according to claim 7, wherein the filter is a narrow-band high-pass filter for allowing only a high band of a frequency component in the image signal to pass therethrough.

9. The authentication object image pickup apparatus according to claim 7, wherein the predetermined range is determined by a distance to the authentication object measured by ranging means.

10. The authentication object image pickup apparatus according to claim 9, wherein the predetermined range is set to be a range of the measured distance ±

20% around the measured distance.

11. The authentication object image pickup apparatus according to any of claims 7 to 10, wherein when the amount of the high luminance component included in the image signal is equal to or greater than the predetermined value, an illuminating direction for the authentication object is switched to capture the image signal.

12. The authentication object image pickup apparatus according to claim 11, wherein when the amount of the high luminance component is not smaller than the predetermined value even if the illuminating direction for the authentication object is switched, the authentication object is illuminated in such an illuminating direction that the high luminance component is the smallest, thereby carrying out a processing of searching for the authentication object focusing position.

14. The authentication object image pickup apparatus according to claim 7, wherein when the amount of the high luminance component included in the image signal is equal to or greater than the predetermined value, the switching means switches to perform the searching process of the peak position of the high frequency component.