Robust step detection using low cost MEMS accelerometer in mobile applications, and processing methods, apparatus and systems
First Claim
1. A system for pedestrian use, the system comprising:
- an accelerometer having multiple electronic sensors;
an electronic circuit operable to generate a signal stream representing magnitude of acceleration sensed by said accelerometer, and to electronically correlate a sliding window of the signal stream with itself to produce peaks at least some of which represent walking steps, and further operable to electronically execute a periodicity check to compare different step periods, and to update a walking-step count, wherein the electronic circuit includes a clock circuit and includes a step frequency module operable in response to the clock circuit and the periodicity check to electronically generate signals representing values proportional to an estimated step frequency; and
an electronic display responsive to said electronic circuit to display information at least in part based on said step count;
wherein the periodicity check includes operations of the electronic circuit to electronically record relative times of successive peaks, and execute a search of pairs of the times over those peaks to find a succession of peaks that are at an equal interval from each other based on the relative times, and to generate an estimate of step period to be at least same as that interval.
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Accused Products
Abstract
A system (10) for pedestrian use includes an accelerometer (110) having multiple electronic sensors; an electronic circuit (100) operable to generate a signal stream representing magnitude of overall acceleration sensed by the accelerometer (110), and to electronically correlate a sliding window (520) of the signal stream with itself to produce peaks at least some of which represent walking steps, and further operable to electronically execute a periodicity check (540) to compare different step periods for similarity, and if sufficiently similar then to update (560) a portion of the circuit substantially representing a walking-step count; and an electronic display (190) responsive to the electronic circuit (100) to display information at least in part based on the step count. Other systems, electronic circuits and processes are disclosed.
10 Citations
43 Claims
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1. A system for pedestrian use, the system comprising:
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an accelerometer having multiple electronic sensors; an electronic circuit operable to generate a signal stream representing magnitude of acceleration sensed by said accelerometer, and to electronically correlate a sliding window of the signal stream with itself to produce peaks at least some of which represent walking steps, and further operable to electronically execute a periodicity check to compare different step periods, and to update a walking-step count, wherein the electronic circuit includes a clock circuit and includes a step frequency module operable in response to the clock circuit and the periodicity check to electronically generate signals representing values proportional to an estimated step frequency; and an electronic display responsive to said electronic circuit to display information at least in part based on said step count; wherein the periodicity check includes operations of the electronic circuit to electronically record relative times of successive peaks, and execute a search of pairs of the times over those peaks to find a succession of peaks that are at an equal interval from each other based on the relative times, and to generate an estimate of step period to be at least same as that interval. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An electronic circuit for use with an accelerometer, the electronic circuit comprising:
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a nonvolatile memory having stored representations of instructions to generate a signal stream representing magnitude of acceleration, to electronically correlate a sliding window of the signal stream with itself to produce peaks at least some of which represent walking steps, and to electronically execute a periodicity check to compare different step periods, and to update a walking-step count; a sensor input port; a display port; and a processor circuit programmably operable in response to the instructions in said nonvolatile memory for at least addition and multiplication and conditional operations responsive to said sensor input port, thereby to effectuate the instructions and drive said display port; wherein the periodicity check includes such instructions to electronically record relative times of successive peaks, and execute a search of pairs of the times over those peaks to find a succession of peaks that are at an equal interval from each other based on the relative times, and to generate an estimate of walking-step length as a function of that interval; and wherein the processor circuit includes a clock circuit and the memory includes a step frequency module for execution by the processor with the periodicity check and with the clock circuit. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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34. A process implemented using an electronic circuit responsive to an accelerometer, the process comprising:
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generating a signal stream representing magnitude of acceleration; electronically correlating a sliding window of the signal stream with itself to produce peaks at least some of which represent walking steps; electronically executing a periodicity check comparing different step periods updating a walking-step count; generating display information at least in part based on the step count;
wherein the periodicity check includes electronically recording relative times of successive peaks, and searching pairs of the times over those peaks to find a succession of peaks that are at an equal interval from each other based on the relative times, and generating an estimate of walking-step length as a function of that interval; andmonitoring step frequency with the periodicity check and a clock circuit. - View Dependent Claims (35, 36, 37, 38, 39, 40, 41, 42, 43)
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Specification