Method And System For Extracting Liveliness Information From Fingertip

• US 20080095412A1
• Filed: 09/13/2005
• Published: 04/24/2008
• Est. Priority Date: 09/13/2004
• Status: Abandoned Application

• Current Assignee: A'Syck Company Limited, The Ritsumeikan Trust (Ritsumei-Kan University Educational Association)
• Original Assignee: A'Syck Company Limited, The Ritsumeikan Trust (Ritsumei-Kan University Educational Association)
• Inventors: Fujieda, Ichiro, Tai, Katsuki
• Application Number:
  US11/661,865
• Publication Number:
  US 20080095412A1
• Time in Patent Office: Days
• US Class Current: 382/124
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/1172 using fingerprinting
• CPC Class Codes: G06V 40/1382 Detecting the live character of the finger, i.e. distinguishing from a fake or cadaver finger

Abstract

The present invention intends to provide a method for liveliness detection and fitness measurement using information optically extracted from a fingertip. For liveliness detection, the present method examines the change in a color index of a finger at its touching portion measured while the finger is being pressed onto an inspection surface and while the finger is released from the same surface. If the change is equal to or larger than a predetermined value, the finger is regarded as a live finger. For fitness measurement, an index indicative of the stiffness of the blood vessel of the finger is obtained from the change in the color index of the finger at its touching portion against the change in the contact area of the finger while the finger is being pressed onto the inspection surface.

Claims

1. A method for extracting liveliness information from a fingertip, which is characterized in that the liveliness information is extracted from a relationship between following two properties of a finger being pressed onto an inspection surface:

the color of the finger at its touching portion, and either a contact area of the finger or a quantity reflecting the contact area.

5. The liveliness detection method according to claim 1, which is characterized in that it uses a light source emitting light within wavelength ranges of green light and red light.

6. The liveliness detection method according to claim 1, which is characterized in that a center of the touching portion is automatically determined by an automatic center determination method.

2. A liveliness detection method using information extracted from a fingertip, which is characterized in that it determines whether or not the finger is a live finger, on a basis of a change in a color index of the finger at its touching portion during one or both of following two phases:

a pressing phase, in which the finger is being pressed onto an inspection surface, and a releasing phase, in which the finger is being released from the inspection surface.

3. The liveliness detection method according to claim 2, which is characterized in that the aforementioned color index is one of following values:

chromaticity coordinate x, chromaticity coordinate y and tristimulus value Y of the CIE color specification system.

4. The liveliness detection method according to claim 2, which is characterized in that the aforementioned color index is one of following values:

the luminance L, hue H and chroma saturation S of an LHS system.

7. A liveliness detection system using information extracted from a fingertip, which is characterized in that it comprises:

a) an inspection surface onto which a finger is to be pressed;

b) a color detector for measuring a color of the finger at a portion touching the inspection surface;

c) a color monitor for checking a color index of the finger at its touching portion during one or both of following phases;

a pressing phase, in which the finger is being pressed onto the inspection surface, and a releasing phase, in which the finger is being released from the inspection surface; and

d) a liveliness detector for determining whether or not the finger is a live finger, on a basis of a change of the color during each of the aforementioned one or both phases.

8. The liveliness detection system according to claim 7, which is characterized in that it uses a light source emitting light within wavelength ranges of green light and red light.

9. A fitness measurement method using information extracted from a fingertip, which is characterized in that an index indicative of a stiffness of a blood vessel of a finger being pressed onto an inspection surface is derived from a change in a color index of the finger at its touching portion, where the color index corresponds to a change in a contact area of the finger or a quantity reflecting the contact area.

10. The fitness measurement method according to claim 9, which is characterized in that the aforementioned color index is one of following values:

chromaticity coordinate x, chromaticity coordinate y and tristimulus value Y of the CIE color specification system.

11. The fitness measurement method according to claim 9, which is characterized in that the aforementioned color index is one of following values:

the luminance L, hue H and chroma saturation S of an LHS system.

12. The fitness measurement method according to claim 9, which is characterized in that a light source emitting light within wavelength ranges of green light and red light is used.

13. The fitness measurement method according to claim 9, which is characterized in that a center of the touching portion is automatically determined by an automatic center determination method.

14. A fitness measurement system using information extracted from a fingertip, which is characterized in that it comprises:

a) an inspection surface onto which a finger is to be pressed;

b) an area-measuring means for measuring either a contact area of the finger on the inspection surface or a quantity reflecting the contact area;

c) a color detector for measuring a color of the finger at a portion touching the inspection surface; and

d) a stiffness calculator for computing an index indicative of a stiffness of a blood vessel of the finger from a change in an index of the aforementioned color corresponding to a change of the contact area.

15. The fitness measurement system according to claim 14, which is characterized in that it uses a light source emitting light within wavelength ranges of green light and red light.