Method and system for determining whether steps have occurred
A filter processes acceleration magnitude signals from an accelerometer device to output spectral content related to walking and running. A device containing the accelerometer determines steps by qualitatively analyzing the processed acceleration signals to determine whether increased acceleration magnitude results from a step impact from running or walking activity. The device may analyze the acceleration signals to determine crossings of an axis at zero magnitude, which crossings typically correspond to a person's foot impacting the ground, and may analyze the period between the zero crossings. The step count can indicate whether the device, in a height determination mode, is moving in a vehicle; if analysis of accelerometer signals indicates no stepping or running, but another circuit of the device indicates rapid movement, the device assumes it is moving in a vehicle, and resets a height above ground value to zero upon determining resumption of walking or running activity.
1. A device for counting steps, comprising:
a processor to:
collect acceleration data, associated with a user of the device, from an accelerometer sensor;
determine a magnitude signal based on the acceleration data collected from the accelerometer sensor;
determine, based on determining the magnitude signal, a first frequency of a first amplitude associated with a fastest stepping speed;
determine, based on determining the magnitude signal, a second frequency of a second amplitude associated with a slowest stepping speed;
establish a filter using the first frequency and the second frequency,
the first frequency being an upper cutoff frequency of the filter, and
the second frequency being a lower cutoff frequency of the filter;
apply the filter to the magnitude signal;
determine based on applying the filter to the magnitude signal:
a minimum half period time threshold associated with the user of the device,
a first half period magnitude threshold associated with the user of the device, and
a maximum half period time threshold associated with the user of the device;
receive sampled pressure data from a pressure sensor;
determine, based on the sampled pressure data, that a change in height above ground by the device has occurred;
determine, via a (Global Positioning System) GPS circuit and based on determining the change in height above ground by the device, a speed value associated with the device;
reset, based on the speed value satisfying a speed threshold, a height above ground value;
turn off, based on the speed value satisfying a speed threshold, the GPS circuit;
receive sampled acceleration data;
determine magnitude acceleration information based on the sampled acceleration data;
determine based on the magnitude acceleration information:
a first negative-to-positive acceleration change,
a positive-to-negative acceleration change succeeding the first negative-to-positive acceleration change, and
a second negative-to-positive acceleration change;
compare a first half period time value and the minimum half period time threshold,
the first half period time value corresponding to a first amount of time between the first negative-to-positive acceleration change and the positive-to-negative acceleration change;
compare the first half period time value and the maximum half period time threshold;
compare, based on the first half period time value satisfying the minimum half period time threshold and the maximum half period time threshold, a magnitude acceleration value, corresponding to the first half period time value, and the first half period magnitude threshold;
compare, based on the magnitude acceleration value satisfying the first half period magnitude threshold, a second half period time value to the minimum half period time threshold,
the second half period time value corresponding to a second amount of time between the positive-to-negative acceleration change and the second negative-to-positive acceleration change;
compare the second half period time value and the maximum half period time threshold;
determine that a step has occurred based on the second half period time value satisfying the minimum half period time threshold and the maximum half period time threshold;
turn on the GPS circuit based on determining that the step occurred; and
output a step signal indicating that the step has occurred.
2. The device of claim 1 , wherein the processor is further to:
increment a pre-step count value based on the step signal indicating that the step has occurred; and
add the pre-step count value to a total step count value based on the pre-step count value reaching a predetermined quantity of step counts.
3. The device of claim 2 , wherein the pre-step count value is reset based on the step not occurring within a predetermined amount of time after a previous step indication.
4. The device of claim 1 , wherein the processor is further to:
filter the sampled acceleration data with a band-pass filter to generate filtered magnitude acceleration information; and
wherein the processor, when comparing the first half period time value and the minimum half period time threshold, is to:
compare the first half period time value and the minimum half period time threshold using values corresponding to the filtered magnitude acceleration information.
5. The device of claim 1 , where the magnitude acceleration value is a first magnitude acceleration value;
wherein the processor is further to:
compare a second magnitude acceleration value, corresponding to the second half period time value, and a second half period magnitude threshold; and
wherein the processor, when determining that the step has occurred, is to:
determine that the step has occurred based on the second magnitude acceleration value satisfying the second half period magnitude threshold.
6. The device of claim 1 , where the magnitude acceleration value is a first magnitude acceleration value; and
wherein the processor is further to:
compare, based on the second half period time value satisfying the maximum half period time threshold, a second magnitude acceleration value, corresponding to a second half period magnitude acceleration, with a second half period magnitude threshold.
7. The device of claim 1 , wherein the processor is further to:
compare a minimum acceleration value to a magnitude acceleration threshold; and
wherein the processor, when determining that the step has occurred, is to:
determine that the step has occurred based on the minimum acceleration value satisfying the magnitude acceleration threshold.
8. The device of claim 1 , wherein the device is a pedometer.
9. The device of claim 1 , wherein the acceleration data is associated with one of:
a walking activity of the user, or
a running activity of the user.
10. A method, comprising:
collecting, by a device, acceleration data, associated with a user of the device, from an accelerometer sensor;
determining, by the device, a magnitude signal based on the acceleration data collected from the accelerometer sensor;
determining, by the device and based on determining the magnitude signal, a first frequency of a first amplitude associated with a fastest stepping speed;
determining, by the device and based on determining the magnitude signal, a second frequency of a second amplitude associated with a slowest stepping speed;
establishing, by the device, a filter using the first frequency and the second frequency,
the first frequency being an upper cutoff of the filter, and
the second frequency being a lower cutoff of the filter;
applying, by the device, the filter to the magnitude signal;
determining by the device and based on applying the filter to the magnitude signal:
a minimum half period time threshold associated with the user of the device,
a first half period magnitude threshold associated with the user of the device, and
a maximum half period time threshold associated with the user of the device;
receiving, by the device, sampled pressure data from a pressure sensor;
determining, by the device and based on the sampled pressure data, that a change in height above ground by the device has occurred;
determining, by the device, via a (Global Positioning System) GPS circuit, and based on determining the change in height above ground by the device, a speed value associated with the device;
resetting, by the device and based on the speed value satisfying a speed threshold, a height above ground value;
turning off, by the device and based on the speed value satisfying a speed threshold, the GPS circuit;
receiving, by the device, a sampled acceleration data;
determining, by the device, magnitude acceleration information based on the sampled acceleration data;
determining, by the device, based on the magnitude acceleration information:
a first negative-to-positive acceleration change,
a positive-to-negative acceleration change succeeding the first negative-to-positive acceleration change, and
a second negative-to-positive acceleration change;
comparing, by the device, a first half period time value and the minimum half period time threshold,
the first half period time value corresponding to a first amount of time between the first negative-to-positive acceleration change and the positive-to-negative acceleration change;
comparing, by the device, the first half period time value and the maximum half period time threshold;
comparing, by the device and based on the first half period time value satisfying the minimum half period time threshold and the maximum half period time threshold, a magnitude acceleration value, corresponding to the first half period time value, and the first half period magnitude threshold;
comparing, by the device and based on the magnitude acceleration value satisfying the first half period magnitude threshold, a second half period time value to the minimum half period time threshold,
the second half period time value corresponding to a second amount of time between the positive-to-negative acceleration change and the second negative-to-positive acceleration change;
comparing, by the device, the second half period time value and the maximum half period time threshold;
determining, by the device, that a step has occurred based on the second half period time value satisfying the minimum half period time threshold and the maximum half period time threshold;
turning on, by the device and based on determining that the step occurred, the GPS circuit; and
outputting, by the device, a step signal indicating that the step has occurred.
11. The method of claim 10 , further comprising:
incrementing a pre-step count value based on the step signal indicating that the step has occurred; and
adding the pre-step count value to a total step count value based on the pre-step count value reaching a predetermined quantity of step counts.
12. The method of claim 11 , further comprising:
resetting the pre-step count value based on the step not occurring within a predetermined amount of time after an immediately previous step indication.
13. The method of claim 10 , further comprising:
filtering the sampled acceleration data with a band-pass filter to generate filtered magnitude acceleration information; and
wherein comparing the first half period time value and the minimum half period time threshold comprises:
comparing the first half period time value and the minimum half period time threshold using values corresponding to the filtered magnitude acceleration information.
14. The method of claim 10 , where the magnitude acceleration value is a first magnitude acceleration value;
wherein the method further comprises:
comparing a second magnitude acceleration value, corresponding to the second half period time value, and a second half period magnitude threshold; and
wherein determining that the step has occurred comprises:
determining that the step has occurred based on the second magnitude acceleration value satisfying the second half period magnitude threshold.
15. The method of claim 10 , where the magnitude acceleration value is a first magnitude acceleration value; and
where the method further comprises:
comparing, based on the second half period time value satisfying the maximum half period time threshold, a second magnitude acceleration value, corresponding to a second half period magnitude acceleration, with a second half period magnitude threshold.
16. The method of claim 15 , where the second magnitude acceleration value corresponds to a minimum magnitude acceleration value associated with the second half period time value.
17. The method of claim 10 , further comprising:
comparing a minimum acceleration value of a second half period to a magnitude acceleration threshold; and
wherein determining that the step has occurred comprises:
determine that the step has occurred based on the minimum acceleration value of the second half period satisfying the magnitude acceleration threshold.
18. The method of claim 10 , where the magnitude acceleration value corresponds to a maximum magnitude acceleration value associated with the first half period time value.
19. A non-transitory computer-readable medium storing instructions, the instructions comprising:
one or more instructions that, when executed by one or more processors of a device, cause the one or more processors to:
collect acceleration data, associated with a user of the device, from an accelerometer sensor;
determine a magnitude signal based on the acceleration data collected from the accelerometer sensor;
determine, based on determining the magnitude signal, a first frequency of a first amplitude associated with a fastest stepping speed;
determine, based on determining the magnitude signal, a second frequency of a second amplitude associated with a slowest stepping speed;
establish a filter using the first frequency and the second frequency,
the first frequency being an upper cutoff frequency of the filter, and
the second frequency being a lower cutoff frequency of the filter;
apply the filter to the magnitude signal;
determine based on applying the filter to the magnitude signal:
a minimum half period time threshold associated with the user of the device,
a first half period magnitude threshold associated with the user of the device, and
a maximum half period time threshold associated with the user of the device;
receive sampled pressure data from a pressure sensor;
determine, based on the sampled pressure data, that a change in height above ground by the device has occurred;
determine, via a (Global Positioning System) GPS circuit and based on determining the change in height above ground by the device, a speed value associated with the device;
reset, based on the speed value satisfying a speed threshold, a height above ground value;
turn off, based on the speed value satisfying a speed threshold, the GPS circuit;
receive sampled acceleration data;
determine magnitude acceleration information based on the sampled acceleration data;
determine based on the magnitude acceleration information:
a first negative-to-positive acceleration change,
a positive-to-negative acceleration change succeeding the first negative-to-positive acceleration change, and
a second negative-to-positive acceleration change;
compare a first half period time value and the minimum half period time threshold,
the first half period time value corresponding to a first amount of time between the first negative-to-positive acceleration change and the positive-to-negative acceleration change;
compare the first half period time value and the maximum half period time threshold;
compare, based on the first half period time value satisfying the minimum half period time threshold and the maximum half period time threshold, a magnitude acceleration value, corresponding to the first half period time value, and the first half period magnitude threshold;
compare, based on the magnitude acceleration value satisfying the first half period magnitude threshold, a second half period time value to the minimum half period time threshold,
the second half period time value corresponding to a second amount of time between the positive-to-negative acceleration change and the second negative-to-positive acceleration change;
compare the second half period time value and the maximum half period time threshold;
determine that a step has occurred based on the second half period time value satisfying the minimum half period time threshold and the maximum half period time threshold;
turn on the GPS circuit based on determining that the step has occurred; and
output a step signal indicating that the step has occurred.
20. The non-transitory computer-readable medium of claim 19 , wherein the one or more instructions, when executed by the one or more processors, further cause the one or more processors to:
increment a pre-step count value based on the step signal indicating that the step has occurred; and
add the pre-step count value to a total step count value based on the pre-step count value reaching a predetermined quantity of step counts.