Method to determine a pressure noise metric for fall detection systems

Patent metadata

Field	Value
Publication number	US-10330494-B2
Application number	US-201414160311-A
Country	US
Kind code	B2
Filing date	Jan 21, 2014
Priority date	Jan 25, 2013
Publication date	Jun 25, 2019
Grant date	Jun 25, 2019

Abstract

A wearable fall-detection device has a variety of sensors, including a pressure sensor, that provide signals for sampling environmental conditions acting on the device. An average of pressure data samples is used to determine a resultant that may indicate an amount of noise in a pressure data signal, and statistical analysis of the noise and the pressure signal average may be used to determine a confidence estimate value that indicates a level of confidence in the amount of noise that a pressure signal is subject to, or includes. The confidence estimate and known fall data, such as change in pressure between a person standing and lying, can create a threshold function that may adapt according to sampled data thus providing a customizable (either statically or dynamically) threshold function for comparing sensor data against rather than comparing data with just a linear threshold function.

First claim

What is claimed is:

1. A method, comprising:
storing, by a device for detecting a fall event, barometric pressure data samples in a first buffer,
the device comprising an accelerometer, and
the barometric pressure data samples being barometric pressure data sampled from a signal generated by a barometric pressure sensor;

storing, by the device and in a second buffer, acceleration data samples,
the acceleration data samples being acceleration data sampled from a signal generated by the accelerometer,
each acceleration data sample corresponding to a respective barometric pressure data sample, and
each acceleration data sample being substantially temporally sampled with the respective barometric pressure data sample;

determining, by the device, that a potential fall event has occurred based on a magnitude of a particular acceleration data sample exceeding a predetermined acceleration magnitude criterion;
selecting, by the device, first barometric pressure data samples in the first buffer having a time of sampling within a predetermined period of time of a sampling of the particular acceleration data sample;
evaluating, by the device, the first barometric pressure data samples to determine confidence estimate values associated with the first barometric pressure data samples;
outputting, by the device, the confidence estimate values;
calculating, by the device, a barometric pressure threshold based on the confidence estimate values;
selecting, by the device, second barometric pressure data samples having a time of sampling during a period of time after the sampling of the particular acceleration data sample;
determining, by the device and based on selecting the second barometric pressure data samples, a change in barometric pressure that occurred between a time before the potential fall event and a time after the potential fall event;
comparing, by the device, the change in barometric pressure and the barometric pressure threshold to determine whether the potential fall event is the fall event; and
outputting, by the device, a signal indicating that the potential fall event is the fall event based on the change in barometric pressure satisfying the barometric pressure threshold.

2. The method of claim 1 , wherein the acceleration data samples are further generated by at least one of:
a gyroscope,
a manometer, or
a proximity sensor.

3. The method of claim 1 , wherein a confidence estimate value, of the confidence estimate values, is a standard deviation of the first barometric pressure data samples in the first buffer.

4. The method of claim 1 , wherein determining that the potential fall event has occurred based on the magnitude of the particular acceleration data sample exceeding the predetermined acceleration magnitude criterion includes at least one of:
determining changes in orientation of the device,
determining a free-fall based on acceleration magnitude signals,
determining an indication in accelerometer data that indicate an impact with a ground,
determining a duration of the indication,
determining a duration of a period of free-fall,
determining a standard deviation of a portion of information associated with one or more of an X-axis, a Y-axis, a Z-axis, or magnitude buffers,
determining a mean of the portion of the information associated with one or more of the X-axis, the Y-axis, the Z-axis, or the magnitude buffers,
determining an area of a spike portion of the information associated with one or more of the X-axis, the Y-axis, the Z-axis, or the magnitude buffers,
determining an area of a free-fall portion of the information associated with one or more of the X-axis, the Y-axis, the Z-axis, or the magnitude buffers,
determining a rate of change of the spike portion of the information associated with one or more of the X-axis, the Y-axis, the Z-axis, or the magnitude buffers,
determining a rate of change of the free-fall portion of the information associated with one or more of the X-axis, the Y-axis, the Z-axis, or the magnitude buffers,
determining a mode of data in the information associated with one or more of the X-axis, the Y-axis, the Z-axis, or the magnitude buffers,
determining a median of data in the information associated with one or more of the X-axis, the Y-axis, the Z-axis, or the magnitude buffers,
determining a minimum of data in one or more X-axis, Y-axis, Z-axis, or magnitude threshold values being met, or
determining a peak X-axis, Y-axis, Z-axis, or magnitude threshold value being met.

5. The method of claim 1 , wherein a confidence estimate value corresponds to an amount of noise included in the signal generated by the barometric pressure sensor.

6. The method of claim 1 , wherein the change in barometric pressure corresponds to a change in altitude of the device.

7. A device, comprising:
a processor to:
store, for detecting a fall event, barometric pressure data samples in a first buffer,
the device comprising an accelerometer, and
the barometric pressure data samples being barometric pressure data sampled from a signal generated by a barometric pressure sensor;

store, in a second buffer, acceleration data samples,
the acceleration data samples being acceleration data sampled from a signal generated by the accelerometer,
each acceleration data sample corresponding to a respective barometric pressure data sample, and
each acceleration data sample being substantially temporally sampled with the respective barometric pressure data sample;

determine that a potential fall event has occurred based on a magnitude of a particular acceleration data sample exceeding a predetermined acceleration magnitude criterion;
select first barometric pressure data samples in the first buffer,
the first barometric pressure data samples having a time of sampling within a predetermined period of time of a sampling of the particular acceleration data sample;

evaluate the first barometric pressure data samples to determine confidence estimate values associated with the first barometric pressure data samples;
output the confidence estimate values;
calculate a barometric pressure threshold based on the confidence estimate values;
select second barometric pressure data samples having a time of sampling during a period of time after the sampling of the particular acceleration data sample;
determine, based on selecting the second barometric pressure data samples, a change in barometric pressure that occurred between a time before the potential fall event and a time after the potential fall event;
compare the change in barometric pressure and the barometric pressure threshold to determine whether the potential fall event is the fall event; and
output a signal indicating the potential fall event is the fall event based on the change in barometric pressure satisfying the barometric pressure threshold.

8. The device of claim 7 , wherein the barometric pressure threshold is derived from fall event data, and
wherein the confidence estimate values define coefficients of the barometric pressure threshold.

9. The device of claim 7 , wherein the barometric pressure threshold is based on at least one of:
a linear function,
a piecewise linear function, or
a polynomial function.

10. The device of claim 8 , wherein the barometric pressure threshold is derived from a barometric pressure data value corresponding to an event of a person rising from a ground to a standing position.

11. The device of claim 7 , wherein a first confidence estimate value corresponds to a first amount of noise included in the signal generated by the barometric pressure sensor, and
wherein a second confidence estimate value corresponds to a second

Assignees

• Verizon Patent & Licensing Inc

Inventors

• Barfield James Ronald
• Welch Stephen Christopher

Classifications

• G01D3/036 Primary

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