Method and device for accurate real-time detection of drowsiness in operators using physiological responses
Inventors
Berckmans, Daniel • Aerts, Jean-Marie • Exadaktylos, Vasileios • Taelman, Joachim
Assignees
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Publication Number
US-11311221-B2
Publication Date
2022-04-26
Expiration Date
Abstract
A method and device for detection of drowsiness of a person, based on a relationship between distal temperature and heart rate and on a balance between body heat loss and body heat production, wherein the distal temperature in a predetermined distal region of the person is monitored as a measure for body heat loss, and the heart rate of the person is monitored as a measure for body heat production, wherein drowsiness in the immediate future is concluded when a change of distal temperature passes a first threshold and, subsequently, a change of the heart rate passes a second threshold or, subsequently, the change of the distal temperature is larger than the change of the heart rate.
Core Innovation
The invention relates to detection of drowsiness of a person having a heart rate and a distal temperature by evaluating a relationship between body heat loss and body heat production. Distal temperature is monitored as a function of time using a temperature sensor, while heart rate is monitored as a function of time using a heart rate sensor. A computing unit processes real-time measured signals from the temperature sensor and the heart rate sensor.
In real time, the computing unit evaluates a change in balance between body heat loss and body heat production by comparing a rate of change of the distal temperature with a first threshold and, after passing the first threshold, comparing a rate of change of the heart rate with a second threshold. A drowsiness signal is generated and the person is alerted when the computing unit detects that the rate of change of distal temperature passes the first threshold and, subsequently, the rate of change of heart rate passes the second threshold. The drowsiness signal comprises an activating signal that prevents and/or delays drowsiness, and generating the drowsiness signal includes initiating the activating signal.
Refinements described in dependent claims include monitoring the distal temperature and/or heart rate using averaged measurements calculated as a moving average and/or a progressing overall mean. Further refinements specify using rates of change of progressing overall mean distal temperature and progressing overall mean heart rate for the first and second threshold comparisons, preserving the sequential conclusion about drowsiness.
Claims Coverage
The document includes two independent claims: one directed to a method and one directed to a device. Each independent claim centers on sequential, real-time threshold comparisons based on rates of change of distal temperature and heart rate, and both independent claims include a drowsiness signal with an activating signal to prevent and/or delay drowsiness.
Real-time sequential rate-of-change threshold comparison of distal temperature then heart rate
A computing unit compares a rate of change of the distal temperature with a first threshold and, after passing the first threshold, compares a rate of change of the heart rate with a second threshold to detect onset of drowsiness, using real-time measured signals and generating a drowsiness signal when the rate of change of distal temperature passes the first threshold and, subsequently, the rate of change of the heart rate passes the second threshold.
Drowsiness signal with activating signal to prevent and/or delay drowsiness
Generating the drowsiness signal comprises an activating signal that prevents and/or delays drowsiness, and the step of generating the drowsiness signal includes initiating the activating signal.
Sensor and computing unit architecture for threshold-based drowsiness signaling
A device includes a temperature sensor for measuring distal temperature as a function of time, a heart rate sensor for measuring heart rate as a function of time, and a computing unit programmed to monitor and compare the measured distal temperature and measured heart rate by comparing a rate of change of the distal temperature with a first threshold and, after detecting passing of the first threshold, comparing a rate of change of heart rate with a second threshold, and causing a drowsiness signal to be generated and causing the person to be alerted when both thresholds are passed in sequence.
Across the independent claims, drowsiness detection is based on sequential real-time thresholding of rates of change: distal temperature rate of change is checked first against a first threshold, and heart rate rate of change is checked subsequently against a second threshold. Both independent claims further require a drowsiness signal that includes an activating signal to prevent and/or delay drowsiness, and the dependent refinements include using moving averages and/or progressing overall means for the monitored signals used in the rate-of-change comparisons.
Stated Advantages
Enables alerting the person when onset of drowsiness is concluded based on sequential threshold detections of distal temperature and heart rate rates of change.
Provides a drowsiness signal that includes an activating signal that prevents and/or delays drowsiness.
Documented Applications
No documented applications found
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