Biometric sensor apparatus and method

• US 8,031,912 B2
• Filed: 05/02/2008
• Issued: 10/04/2011
• Est. Priority Date: 05/04/2007
• Status: Active Grant

• Current Assignee: Stmicroelectronics (Research & Development) Limited (STMicroelectronics NV)
• Original Assignee: Stmicroelectronics (Research & Development) Limited (STMicroelectronics NV)
• Inventors: Fawaz, Khodor, Dennis, Carl
• Primary Examiner(s): CARTER, AARON W
• Application Number:
  US12/114,246
• Publication Number:
  US 20080273768A1
• Time in Patent Office: 1,250 Days
• Field of Search: 382/115, 382116-127, 340/5.1, 340/5.2, 340/5.52, 340/5.53, 340 58- 586, 356/71, 713/186, 902/3
• US Class Current: 382/115
• CPC Class Codes: G06V 40/1394 using acquisition arrangements
• CPC Class Codes: G06V 40/40 Spoof detection, e.g. liveness detection
• CPC Class Codes: G06V 40/45 Detection of the body part being alive

Abstract

A biometric sensor apparatus uses an infra red light source and a CMOS image sensor. A platen receives a body part and the image sensor receives light transmitted through the body part. A processor determines from the detected through-transmitted light whether the body part is live or is a spoof body part. This determination is based upon a detected variation of the opacity of the body part due to blood flow through the body part. Digital processing of the collected image signal data is performed, such as by smoothing. The sensor may further function as a pattern (such as a fingerprint) sensor for detecting surface patterns on the presented body part and identifying an individual from those sensed patterns.

Claims

1. A biometric sensor apparatus comprising:

a plurality of light sources arranged to irradiate an object presented for biometric identification, wherein at least two of said light sources emit light at different wavelengths;

a circuit configured to pseudo randomly select a light source from said plurality of light sources for irradiating the object;

an optical image sensor configured to capture radiation that has passed at least part way through the object; and

a data processor configured to process signals output from the image sensor, the data processor configured to calculate at least one value representative of a parameter indicating a likelihood of whether the object is a body part and further determine a likelihood that the object is a body part.

2. The biometric sensor apparatus as claimed in claim 1 wherein the optical image sensor is arranged in a transmission arrangement, or in a reflectance arrangement.

3. The biometric sensor apparatus as claimed in claim 1 further comprising a CMOS image sensor.

4. The biometric sensor apparatus as claimed in claim 1 wherein the data processor is configured to calculate at least one value representative of a parameter indicative of blood flow through a body member.

5. The biometric sensor apparatus as claimed in claim 1 wherein the data processor is configured to analyze the output of the image sensor for characteristics of spoofing.

6. The biometric sensor apparatus as claimed in claim 1 wherein the data processor is configured to identify any one, or combination, of the following within the output of the image sensor:

systolic notch, dicrotic notch, incisura, peak.

7. The biometric sensor apparatus as claimed in claim 1, wherein one of the light sources is a source of infra red radiation.

8. The biometric sensor apparatus as claimed in claim 1 wherein one of the light sources is a visible light source and wherein the data processor is configured to derive an optical pattern associated with the object from the output of the optical sensor in the visible region.

9. The biometric sensor apparatus as claimed in claim 8 wherein the optical pattern is a fingerprint.

10. The biometric sensor apparatus as claimed in claim 1 wherein the optical sensor is arranged to capture said radiation in either a time limited mode, a set number of cardiac cycles mode, or a continuous scanning mode.

11. The biometric sensor apparatus as claimed in claim 1 comprising a platen arranged to receive the object.

12. The biometric sensor apparatus as claimed in claim 1, wherein the image sensor is a CMOS image sensor array.

13. A method for determining whether an object presented to a biometric sensor device is a live body part, comprising:

illuminating an object presented for biometric identification with a light source selected from a plurality of light sources operable at different wavelengths;

making the selection of the light source from the plurality of light sources in a pseudo random manner;

detecting a variation in opacity of said object with respect to time using an image sensor;

determining at least one value representative of a parameter indicating the likelihood of whether the object is a body part; and

analyzing variations in the at least one value to determine whether said object is a live body part.

14. The method of claim 13 wherein analyzing comprises analyzing a signal comprising the at least one value to determine critical points.

15. The method of claim 13 comprising determining whether the at least one value is indicative of the characteristics of a heartbeat.

16. A biometric scanning device comprising:

an apparatus configured to;

illuminate an object presented for biometric identification with radiation from a plurality of light sources, wherein at least two of said light sources emit light at different wavelengths;

pseudo randomly select the light source from the plurality of light sources for illuminating the object;

detect a variation in opacity of said object with respect to time using an image sensor;

determine at least one value representative of a parameter indicating the likelihood of whether the object is a body part; and

analyze variations in the at least one value to determine whether said object is a live body part;

wherein the device comprises any one, or combination, of the following;

a fingerprint scanner, a retinal scanner, a palm scanner, a body part scanner adapted to scan any given body part.

17. A biometric sensor apparatus comprising:

at least one light source configured to irradiate an object presented for biometric identification;

a sensor configured to sense the irradiation light to detect a variation in opacity of said object with respect to time, wherein the detected variation in opacity is indicative of blood flow within the object; and

a processor configured to process the sensed variations in opacity to determine existence in the sensed variations of a systolic notch, incisura and dicrotic/diastolic notch relating to blood flow, and further analyze the existence information to determine whether said object is a living body part.

18. The biometric sensor apparatus of claim 17 wherein the sensor further functions as a fingerprint or handprint sensor, the processor further functioning responsive to sensed fingerprint or handprint pattern data to make an identification of the object.

19. The biometric sensor apparatus of claim 17 wherein the at least one light source comprises a plurality of light sources, at least two of the plurality of light sources emitting radiation at different wavelengths, and further comprising a circuit configured to pseudo randomly select a light source from said plurality of light sources for irradiating the object.

20. The biometric sensor apparatus of claim 17 wherein said processor is further configured to process the sensed variations in opacity to determine locations in the sensed variations of the systolic notch, incisura and dicrotic/diastolic notch relative to each other, and further analyze the existence and relative location information to determine whether said object is a living body part.

21. A biometric sensor apparatus comprising:

a plurality of light sources arranged to irradiate an object presented for biometric identification, wherein at least two of said light sources emit light at different wavelengths;

a circuit configured to pseudo randomly select a light source from said plurality of light sources for irradiating the object;

an optical image sensor configured to capture radiation that has passed at least part way through the object and generate signals indicative thereof; and

a data processor configured to process said signals generated by the image sensor to determine a likelihood of whether the object is a live body part.

22. A method for determining whether an object presented to a biometric sensor device is a live body part, comprising:

illuminating an object presented for biometric identification with a light source selected from a plurality of light sources operable at different wavelengths;

making the selection of the light source from the plurality of light sources in a pseudo random manner;

detecting a variation in opacity of said object with respect to time using an image sensor;

processing signals indicative of said variation in opacity to determine a likelihood of whether the object is a live body part.