Biometric detection module with denoising function and biometric detection method thereof

• US 10,092,244 B2
• Filed: 04/14/2015
• Issued: 10/09/2018
• Est. Priority Date: 07/08/2014
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: PixArt Imaging Incorporated
• Inventors: Chuang, Chih-Yuan, Tsai, Cheng-Nan, Kao, Ming-Tsan, Gu, Ren-Hau, Chang, Yen-Min
• Primary Examiner(s): KUHLMAN, CATHERINE BURK
• Application Number:
  US14/685,782
• Publication Number:
  US 20160007929A1
• Time in Patent Office: 1,274 Days
• CPC Class Codes: A61B 2562/0238 Optical sensor arrangements for performing transmission measurements on body tissue
• CPC Class Codes: A61B 5/02427 Details of sensor
• CPC Class Codes: A61B 5/02433 for infrared radiation
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6803 Head-worn items, e.g. helmets, masks, headphones or goggles
• CPC Class Codes: A61B 5/6815 Ear
• CPC Class Codes: A61B 5/7214 using signal cancellation, e.g. based on input of two identical physiological sensors spaced apart, or based on two signals derived from the same sensor, for different optical wavelengths
• CPC Class Codes: A61B 5/725 using specific filters therefor, e.g. Kalman or adaptive filters A61B5/316 take precedence
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence

Abstract

A biometric detection module including a light source module, a detection region and a control module is provided. The light source module is configured to emit green light, red light and IR light in a time division manner to illuminate a skin surface. The detection region is configured to detect penetration light emitted from the light source module for illuminating the skin surface and passing through body tissues to correspondingly generate a green light signal, a red light signal and an IR light signal. The control module is configured to determine a filtering parameter according to the green light signal to accordingly filter the red light signal and the IR light signal, and calculate a biometric characteristic according to at least one of the green light signal, a filtered red light signal and a filtered IR light signal.

Claims

1. A biometric detection module, configured to be attached to an eyeglass temple and detect at least one biometric characteristic from a skin region behind an ear, the biometric detection module comprising:

a detection unit comprising;

a light source module configured to emit green light, red light and infrared light in a time division manner to illuminate the skin region;

a detection region configured to detect penetrating light emitted from the light source module for illuminating the skin region and passing through body tissues to correspondingly generate a green light signal, a red light signal and an infrared light signal; and

at least one processor configured to

control the light source module to emit light,

convert the green light signal to frequency domain to determine a filtering parameter according to a frequency domain green light signal,

respectively convert the red light signal and the infrared light signal to a frequency domain red light signal and a frequency domain infrared light signal,

filter the frequency domain red light signal and the frequency domain infrared light signal using the filtering parameter, to obtain a filtered red light signal and a filtered infrared light signal, respectively, and

calculate the biometric characteristic according to at least one of the green light signal, the filtered red light signal and the filtered infrared light signal; and

an abrasion-proof layer covering the detection region and having an upper surface as a detection surface, wherein

a thickness of the abrasion-proof layer is smaller than 100 micrometers, and

the upper surface is configured to be in contact with the skin region when detecting the biometric characteristic such that the light emitted from the light source module illuminates the skin region and sequentially passes through the body tissues and the abrasion-proof layer to be detected by the detection region.

2. The biometric detection module as claimed in claim 1, further comprising:

a joint portion configured to combine with the eyeglass temple; and

an adjustment portion connected between the joint portion and the detection unit, and configured to adjust a position of the detection unit,

wherein the detection surface is configured to be attached to the skin region behind the ear.

3. The biometric detection module as claimed in claim 1, wherein the at least one biometric characteristic comprises a heart rate, a blood oxygenation and a second derivative of photoplethysmogram.

4. The biometric detection module as claimed in claim 3, wherein the at least one processor is configured to

calculate the heart rate and the second derivative of photoplethysmogram according to one of the green light signal, the filtered red light signal and the filtered infrared light signal, and

calculate the blood oxygenation according to the filtered red light signal and the filtered infrared light signal.

5. The biometric detection module as claimed in claim 1, wherein the filtering parameter is a basic frequency of the frequency domain green light signal.

6. The biometric detection module as claimed in claim 5, wherein the at least one processor is configured to

obtain the filtered red light signal by converting signal components at the basic frequency of the frequency domain red light signal back to time domain, and

obtain the filtered infrared light signal by converting signal components at the basic frequency of the frequency domain infrared light signal back to the time domain.

7. The biometric detection module as claimed in claim 1, wherein the biometric detection module is attached to glasses with a display function for showing the biometric characteristic.

8. A biometric detection module, configured to detect at least one biometric characteristic from a skin region in a concha, the biometric detection module comprising:

a detection unit comprising;

a light source module configured to emit green light, red light and infrared light in a time division manner to illuminate the skin region;

a detection region configured to detect penetrating light emitted from the light source module for illuminating the skin region and passing through body tissues to correspondingly generate a green light signal, a red light signal and an infrared light signal; and

at least one processor configured to

control the light source module to emit light,

convert the green light signal to frequency domain to determine a filtering parameter according to a frequency domain green light signal,

respectively convert the red light signal and the infrared light signal to a frequency domain red light signal and a frequency domain infrared light signal,

filter the frequency domain red light signal and the frequency domain infrared light signal using the filtering parameter determined from the frequency domain green light signal, to obtain a filtered red light signal and a filtered infrared light signal, and

calculate the biometric characteristic according to at least one of the green light signal, the filtered red light signal and the filtered infrared light signal; and

an abrasion-proof layer covering the detection region and having an upper surface as a detection surface, wherein

a thickness of the abrasion-proof layer is smaller than 100 micrometers, and

the upper surface is configured to be in contact with the skin region when detecting the biometric characteristic such that the light emitted from the light source module illuminates the skin region and sequentially passes through the body tissues and the abrasion-proof layer to be detected by the detection region.

9. The biometric detection module as claimed in claim 8, further comprising:

a main body;

a protrusion portion protruding outward from the main body and configured to be put in the concha;

a power module disposed in the main body and configured to provide power to the detection unit, and

an indication unit disposed in the main body and configured to show the biometric characteristic,

wherein the detection unit is at the protrusion portion, and the detection surface is configured to be attached to the skin region in the concha.

10. The biometric detection module as claimed in claim 8, wherein the at least one biometric characteristic comprises a heart rate, a blood oxygenation and a second derivative of photoplethysmogram.

11. The biometric detection module as claimed in claim 10, wherein the at least one processor is configured to

calculate the heart rate and the second derivative of photoplethysmogram according to one of the green light signal, the filtered red light signal and the filtered infrared light signal, and

calculate the blood oxygenation according to the filtered red light signal and the filtered infrared light signal.

12. The biometric detection module as claimed in claim 8, wherein the filtering parameter is a basic frequency of the frequency domain green light signal.

13. The biometric detection module as claimed in claim 12, wherein the at least one processor is configured to

obtain the filtered red light signal by converting signal components at the basic frequency of the frequency domain red light signal back to time domain, and

obtain the filtered infrared light signal by converting signal components at the basic frequency of the frequency domain infrared light signal back to the time domain.

14. The biometric detection module as claimed in claim 8, wherein the detection region comprises photodiodes respectively configured to detect the red light, the infrared light and the green light.

15. The biometric detection module as claimed in claim 8, wherein the biometric detection module is attached to an earphone.

16. A biometric detection method of a biometric detection module, the biometric detection module comprising a light source module, an abrasion-proof layer and a detection region and configured to detect at least one biometric characteristic from a skin surface, wherein the abrasion-proof layer covers the detection region, has an upper surface as a detection surface and has a thickness smaller than 100 micrometers, and the upper surface is in contact with the skin surface when detecting the biometric characteristic, the biometric detection method comprising:

emitting, using the light source module, green light, red light and infrared light in a time division manner to illuminate the skin surface;

detecting, using the detection region, penetrating light emitted from the light source module for illuminating the skin surface and sequentially passing through body tissues and the abrasion-proof layer to correspondingly generate a green light signal, a red light signal and an infrared light signal;

converting the green light signal to frequency domain and determining a filtering parameter according to a frequency domain green light signal;

converting the red light signal and the infrared light signal respectively to a frequency domain red light signal and a frequency domain infrared light signal;

filtering the frequency domain red light signal and the frequency domain infrared light signal with the filtering parameter and generating a filtered red light signal and a filtered infrared light signal; and

calculating the biometric characteristic according to at least one of the green light signal, the filtered red light signal and the filtered infrared light signal.

17. The biometric detection method as claimed in claim 16, wherein the determining comprises:

taking a basic frequency of the frequency domain green light signal as the filtering parameter.

18. The biometric detection method as claimed in claim 17, further comprising:

converting signal components at the basic frequency of the frequency domain red light signal and the frequency domain infrared light signal back to time domain to generate the filtered red light signal and the filtered infrared light signal.