Systems and methods for motion detection
AssigneeInvenSense, Inc.
InventorWilliam Kerry Keal
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Abstract
Systems and methods are disclosed for characterizing motion of a device by taking the difference between pairs of sensor signal samples and comparing an expected higher order moment for the differences determined from an observed first order moment for the differences and/or an observed second order moment for the differences and the observed higher order moment for the differences. A determination of whether the device is experiencing motion may be made based on a comparison of the difference of the moments to a threshold.
Claims32
A method for characterizing a motion of a device, comprising:
- obtaining a data signal from a motion sensor of the device, wherein the data signal comprises a plurality of samples provided at a sampling frequency;
- computing differences between pairs of the plurality of samples;
- performing a calculation corresponding to subtracting an expected higher order moment for the differences from an observed higher order moment for the differences to obtain a difference of the moments, wherein the expected higher order moment is based at least in part on an observed first order moment for the differences and an observed second order moment for the differences;
- and determining whether the device is experiencing motion based at least in part on a comparison of the difference of the moments to a threshold.
A sensor device comprising;
- at least one motion sensor outputting a data signal, wherein the data signal comprises a plurality of samples provided at a sampling frequency;
- and a motion detection module configured to:
- compute differences between pairs of the plurality of samples;
- perform a calculation corresponding to subtracting an expected higher order moment for the differences from an observed higher order moment for the differences to obtain a difference of the moments, wherein the expected higher order moment is based at least in part on an observed first order moment for the differences and an observed second order moment for the differences;
- and determine whether the device is experiencing motion based at least in part on a comparison of the difference of the moments to a threshold.
An integrated sensor processing unit characterizing a motion of a device, comprising:
- at least one motion sensor outputting a data signal, wherein the data signal comprises a plurality of samples provided at a sampling frequency;
- and a processor configured to:
- compute differences between pairs of the plurality of samples;
- compute a first order moment for the differences;
- compute a second order moment for the differences;
- derive a higher order moment for the differences using only the computed first order moment and the computed second order moment;
- estimate a higher order moment for the differences using only an average of the differences taken to a power corresponding to the higher order moment;
- subtract the derived higher order moment for the differences from the estimated higher order moment for the differences;
- and determine wherein the device is experiencing motion based at least in part on a comparison of the result of the subtraction to a threshold.
Dependencies are inferred from the claim text.