System and method for detecting sleepiness

• US 7,887,489 B2
• Filed: 08/29/2008
• Issued: 02/15/2011
• Est. Priority Date: 05/22/2008
• Status: Active Grant

• Current Assignee: Telecommunication & Electronics, Inc.
• Original Assignee: Telecommunication & Electronics, Inc.
• Inventors: Lee, Jae Jin, Kim, Chung Hwan, Kim, Min Gun
• Primary Examiner(s): Marmor, II; Charles A
• Assistant Examiner(s): D'ANGELO, MICHAEL J
• Application Number:
  US12/520,246
• Publication Number:
  US 20100234741A1
• Time in Patent Office: 900 Days
• Field of Search: 600/484, 600/493, 600/500, 600/508, 600/509, 600/483, 340/573.1, 340/575, 340/576
• US Class Current: 600/484
• CPC Class Codes: A61B 2503/22 Motor vehicles operators, e.g. drivers, pilots, captains
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/0507 using microwaves or terahertz waves
• CPC Class Codes: A61B 5/1102 Ballistocardiography
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/7455 characterised by tactile indication, e.g. vibration or electrical stimulation
• CPC Class Codes: G08B 21/06 indicating a condition of sleep, e.g. anti-dozing alarms

Abstract

The present invention relates to a drowsiness detection method. A heartbeat signal and a breathing signal are detected by exploiting together a scheme and an optical system scheme. The detected signals are applied to respective amplification units, noise signals are eliminated from the detected signals, and noise-free signals are amplified. The amplified signals are applied to a central processing unit, signal processing is processed on the signals, and processed signals are combined. The combined signal is counted, and a warning sound, voice message or vibration is output in a case where a value, obtained by subtracting a counted output value monitored one minute before a current time, from a counted output value monitored two minutes before the current time, falls within a detection range and where, with a passage of time, the value falling within the detection range is successively detected from two to ten times.

Claims

1. A drowsiness detection method, comprising:

a first step of detecting a heartbeat signal and a breathing signal without making direct contact with a target body by exploiting together a scheme using a principle of a Doppler radar and an optical system scheme using a light source/photodetector so that a heartbeat can be detected when a human body is moving;

a second step of applying the signals, detected by the scheme using the principle of the Doppler radar and the optical system scheme using the light source/photodetector to respective amplification units, eliminating noise signals from the detected signals, respectively, and amplifying noise-free signals;

a third step of applying signals output at the second step to a central processing unit, performing signal processing on the signals, and combining respective processed signals; and

a fourth step of counting an output value output at the third step, and outputting a warning sound, voice message or vibration through an output unit in a case where a value, obtained by subtracting a counted output value which was monitored one minute before a current time, from a counted output value which was monitored two minutes before the current time, falls within a range from 2 to 10, or from −

2 to −

10 and where, with a passage of time, the value falling within the range from 2 to 10 or from −

2 to −

10 is successively detected from two to ten times within a same range.

2. The drowsiness detection method according to claim 1, wherein the optical system comprises a filter unit arranged upstream of a photodetection unit and configured to allow only light, having a specific wavelength and a predetermined light source bandwidth, to pass therethrough.

3. The drowsiness detection method according to claim 2, wherein the light source bandwidth is less than 100 nm.

4. The drowsiness detection method according to claim 2, wherein the light source is implemented using a Light Emitting Diode (LED) or a Laser Diode (LD).

5. The drowsiness detection method according to claim 2, wherein the light source uses visible, infrared or ultraviolet rays.

6. The drowsiness detection method according to claim 1, wherein the light source is implemented using a Light Emitting Diode (LED) or a Laser Diode (LD).

7. The drowsiness detection method according to claim 1, wherein the light source uses visible, infrared or ultraviolet rays.

8. A drowsiness detection system, comprising:

a heart rate monitor including a radar system and an optical system, an amplification unit, a central processing unit and an output unit,

wherein the radar system comprises;

a signal generator for generating specific frequency signals;

a coupler for receiving the signals generated by the signal generator and dividing a second signal, which is a reference frequency signal, and a first signal to be radiated to a heart of a target body, and outputting the first and second signals;

a transmission antenna for receiving the first signal from the coupler and radiating the first signal to the heart of the target body;

a reception antenna for receiving a reflected wave which is returned from the heart of the target body after the first signal has been transmitted through the transmission antenna and has been incident on the heart of the target body;

a low-noise amplifier for amplifying a signal received through the reception antenna;

a mixer for mixing the second signal output from the coupler with the signal amplified by the low-noise amplifier; and

a signal processing unit for amplifying a signal output from the mixer, filtering the amplified signal, converting the filtered signal into a digital signal, and outputting the digital signal, and

wherein the optical system comprises;

a light source unit including a light source for generating light and a light transmission optical system for radiating light to a portion identical to a heart region of the target body to which the signal is radiated by the transmission antenna of the radar system;

a photodetection unit including a light reception optical system for detecting a light signal reflected from the target body after being radiated to the target body;

a motion signal processing unit for extracting a noise signal attributable to a motion of the target body from the signal detected by the photodetection unit; and

a digital signal processing unit for converting the noise signal extracted by the motion signal processing unit into a digital signal and outputting the digital signal,

wherein the heart rate monitor further comprises;

a combiner for eliminating the noise signal output from the digital signal processing unit of the optical system from the signal output from the signal processing unit of the radar system; and

a biological signal recognition unit for obtaining biological signals from the combiner,

wherein the amplification unit receives signals respectively detected by a scheme using a principle of the Doppler radar and a scheme of the optical system using the light source/photodetector, eliminates noise signals from the detected signals, respectively, and amplifies the noise-free signals, and

wherein the central processing unit individually receives signals output from the amplification unit, performs signal processing on the signals, combines the processed signals with each other, counts each of values output from the amplification unit, monitors the output value, and outputs a warning sound, voice message or vibration through the output unit if it is determined as a result of the monitoring that the output value falls within a detection range.

9. The drowsiness detection system according to claim 8, wherein the detection range is a range in which a value, obtained by subtracting a counted output value which was monitored one minute before a current time from a counted output value which was monitored two minutes before the current time through processing of the central processing unit which counts the output value, falls within a range of 2 to 10 and in which the value falling within the range from 2 to 10 is successively detected from two to ten times with passage of time.

10. The drowsiness detection system according to claim 9, wherein the light source is implemented using a Light Emitting Diode (LED) or a Laser Diode (LD).

11. The drowsiness detection system according to claim 9, wherein the light source uses visible, infrared or ultraviolet rays.

12. The drowsiness detection system according to claim 8, wherein the optical system further comprises a filter unit arranged upstream of the photodetection unit and configured to allow only light, having a specific wavelength and a predetermined light source bandwidth, to pass therethrough.

13. The drowsiness detection system according to claim 12, wherein the light source bandwidth is less than 100 nm.

14. The drowsiness detection system according to claim 12, wherein the light source is implemented using a Light Emitting Diode (LED) or a Laser Diode (LD).

15. The drowsiness detection system according to claim 12, wherein the light source uses visible, infrared or ultraviolet rays.