Method for detecting acceleration peaks with non-uniform sampling

Patent metadata

Field	Value
Publication number	US-11162971-B2
Application number	US-201916359236-A
Country	US
Kind code	B2
Filing date	Mar 20, 2019
Priority date	Mar 21, 2018
Publication date	Nov 2, 2021
Grant date	Nov 2, 2021

Abstract

A method for determining information regarding the displacement of an object from measurements provided by an accelerometer associated with the object. The method comprises the steps of detecting acceleration peaks in the measurements, of calculating one or more characteristics of the acceleration peaks detected, and of determining a mode of travel of the object from the characteristics of the acceleration peaks. The measurements undergo non-uniform resampling upon the detection of local extrema.

First claim

What is claimed is:

1. A method for determining information regarding the displacement of an object, comprising the steps of:
non-uniformly sampling of measurements provided by an accelerometer associated with the object, the non-uniformly sampling comprising:
a regular sampling of measurements,
a detection of local extrema in the regularly sampled measurements, and
a non-uniform resampling of the measurements carried out to keep the detected local extrema,

detecting acceleration peaks in the measurements provided by the accelerometer associated with the object,
calculating one or more characteristics of the detected acceleration peaks, and
determining a mode of travel of the object from the one or more calculated characteristics, wherein the step of non-uniformly sampling the measurements is performed before the step of detecting the acceleration peaks.

2. The method according to claim 1 , wherein the non-uniform resampling is furthermore carried out in order to keep a sample when a duration separating said sample from a previously kept sample is greater than a time threshold.

3. The method according to claim 1 , wherein the non-uniform resampling is furthermore carried out in order to keep a sample when an amplitude variation between said sample and a previously kept sample is greater than an amplitude threshold.

4. The method according to claim 1 , wherein the non-uniform resampling is furthermore carried out in order to keep randomly selected samples.

5. The method according to claim 1 , wherein the detection of local extrema is carried out from a sliding-window covering a plurality of successive samples.

6. The method according to claim 5 , wherein the detection of local extrema further comprises storing the extremum type of the last extremum detected in memory.

7. The method according to claim 1 , wherein the detection of local extrema comprises correlating the regularly sampled samples with one or more predetermined waveforms, and detecting a local extremum when a correlation peak is identified.

8. The method according to claim 1 , wherein the step of detecting the acceleration peaks comprises determining a direction of travel of the object, determining an acceleration peak detection threshold from the non-uniformly sampled measurements projected in the direction of travel of the object and comparing the amplitude of the non-uniformly sampled measurements with the acceleration peak detection threshold.

9. The method according to claim 8 , wherein the determination of the acceleration peak detection threshold comprises calculating the variance of the non-uniformly sampled measurements.

10. The method according to claim 8 , further comprising comparing the amplitude of the non-uniformly sampled measurements with a noise threshold and wherein an acceleration peak is formed of successive non-uniformly sampled measurements, the amplitude whereof is greater than the noise threshold, and includes at least one measurement, the amplitude whereof is greater than the acceleration peak detection threshold.

11. The method according to claim 1 , wherein the step of calculating one or more characteristics of the detected acceleration peaks comprises determining at least one characteristic from the following group of characteristics: mean amplitude, mean duration and frequency.

12. A computer program comprising instructions for executing the method according to claim 1 , when said program is executed on a computer.

13. A device comprising a data processing unit configured to implement the method according to claim 1 .

Assignees

• Commissariat Energie Atomique

Inventors

• Leirens Sylvain

Classifications

• G01P15/00 Primary

  Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration · CPC title

• G01C21/10 Primary

  by using measurements of speed or acceleration (G01C21/24, G01C21/26 take precedence) · CPC title

• A61B5/1123

  Discriminating type of movement, e.g. walking or running (A61B5/1116, A61B5/112 take precedence) · CPC title

• H03M1/1275

  at extreme values only · CPC title