Predictive drowsiness alarm method

• US 9,033,892 B2
• Filed: 09/26/2011
• Issued: 05/19/2015
• Est. Priority Date: 05/17/2011
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Su, Yu Jen, Lee, Yen Hsien, Chang, Kuang I
• Primary Examiner(s): Kahelin, Michael
• Assistant Examiner(s): FAIRCHILD, MALLIKA DIPAYAN
• Application Number:
  US13/245,205
• Publication Number:
  US 20120296226A1
• Time in Patent Office: 1,331 Days
• Field of Search: 600/516, 600/508, 600/519
• US Class Current: 600/508
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/18 for vehicle drivers or machine operators
• CPC Class Codes: G08B 21/06 indicating a condition of sleep, e.g. anti-dozing alarms
• CPC Class Codes: G08B 31/00 Predictive alarm systems characterised by extrapolation or other computation using updated historic data

Abstract

A method for predicting drowsiness is disclosed. By obtaining average heart beat rate values of a driver, and according to the characteristics of the heart beat rate values over a period of time, the method is utilized to determine whether the human being is going to sleep. The method comprises the following steps: detecting a heart beat rate of a driver; calculating a curve of the heart beat rate average during a time interval of X minutes; determining an accumulated length of duration during which the calculated linear regression slope values are smaller than the predetermined slope value Z; determining whether the accumulated length of duration is greater than a time threshold T to generate a drowsiness detecting result; and determining whether to raise an alarm based on the drowsiness detecting result.

Claims

1. A predictive drowsiness alarm method comprising the following steps:

detecting a heart beat rate of a driver by an electrocardiographic device or an ultra frequency antenna;

calculating a curve of a heart beat rate average during a time interval of X minutes, wherein the heart rate average during a time interval of X minutes is accumulated heart beat rates during X minutes divided by X minutes;

calculating a plurality of linear regression slopes of the curve of the heart beat rate average during a time interval of Y minutes;

determining an accumulated length of duration during which the calculated linear regression slope values are smaller than a predetermined slope value Z; and

determining whether the accumulated length of duration is greater than a time threshold T to generate a drowsiness detecting result by using a computer, wherein X ranges from 1 to 10, Y ranges from 1 to 10, Z ranges from −

0.001 to −

0.1, and T ranges from 60 to 600 seconds.

2. The predictive drowsiness alarm method of claim 1, further comprising a step of determining whether to raise an alarm based on the drowsiness detecting result.

3. The predictive drowsiness alarm method of claim 1, further comprising a step of calculating, based on a time interval, the value of the accumulated length of duration, wherein the time interval ranges from 1 second to 60 seconds.

4. The predictive drowsiness alarm method of claim 3, further comprising a step of calculating, based on the time interval, a rate of change of the linear regression slopes, wherein the rate of change is defined as the difference between the linear regression slope during a first time interval and the linear regression slope during a second time interval.

5. The predictive drowsiness alarm method of claim 4, wherein the first time interval and the second time interval range from 1 to 60 seconds.

6. The predictive drowsiness alarm method of claim 4, further comprising a step of determining whether the rate of change is smaller than a predetermined threshold M of the rate of change to determine the drowsiness detecting result, wherein the threshold M ranges from −

0.001 to −

0.1.

7. The predictive drowsiness alarm method of claim 3, further comprising a step of performing a Fourier transformation on the curve of the heart beat rate average to obtain a plurality of low-frequencies in a Fourier spectrum over a time interval of Y minutes.

8. The predictive drowsiness alarm method of claim 7, further comprising a step of calculating, based on a time interval, a rate of change of the low-frequencies, wherein the rate of change is defined as the change in the low-frequencies between a first time interval and a second time interval.

9. The predictive drowsiness alarm method of claim 8, wherein the first time interval and the second time interval range from 1 to 60 seconds.

10. The predictive drowsiness alarm method of claim 8, further comprising a step of determining whether the rate of change is greater than a predetermined threshold N of the rate of change to determine the drowsiness detecting result, wherein N is greater than 1.

11. The predictive drowsiness alarm method of claim 8, wherein the low-frequencies range from 0.0005 to 0.005 Hz.

12. The predictive drowsiness alarm method of claim 1, wherein the step of calculating the linear regression slopes of the curve of the heart beat rate average during the time interval of Y minutes, wherein the linear regression slopes are referred to an individual weighing value, and the predictive drowsiness alarm method further comprises a step of determining whether the weighing value is greater than a predetermined threshold to generate the drowsiness detecting result.