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US 8,818,748 B2Granted
Posture sensor automatic calibration
AssigneeCardiac Pacemakers, Inc.
InventorsJohn D. Hatlestad, Aaron Lewicke, Keith R. Maile
Life of this patent
Estimating the term…
Abstract
A system and method automatically calibrate a posture sensor, such as by detecting a walking state or a posture change. For example, a three-axis accelerometer can be used to detect a patient's activity or posture. This information can be used to automatically calibrate subsequent posture or acceleration data.
Claims20
A device comprising:
- an accelerometer configured to sense an acceleration signal from a patient;
- a filter circuit configured to extract a characteristic of the acceleration signal;
- a comparison circuit configured to perform a comparison between the characteristic of the acceleration signal and a stored template to distinguish a walking state of the patient from a non-walking activity state of the patient;
- and
- a posture calibration circuit configured to use an orientation of the accelerometer in the walking state to perform a posture calibration of the acceleration signal of the accelerometer.
2 more elements
A device comprising:
- an accelerometer configured to sense an acceleration signal from a patient;
- a first filter circuit configured to extract a first component of the acceleration signal;
- a comparison circuit configured to perform a comparison between a characteristic of the first component of the acceleration signal and a stored template to distinguish a walking state of the patient from a non-walking activity state of the patient;
- a second filter circuit configured to extract a second component of the acceleration signal;
- a signal processor circuit configured to:
- determine a gravity vector using the second component of the acceleration signal;
- compute a parallel component of the acceleration signal, the parallel component being in the direction of the gravity vector;
- compute an orthogonal component of the acceleration signal, the orthogonal component being in a direction orthogonal to the gravity vector;
- compare the parallel component to a parallel template and compare the orthogonal component to an orthogonal template;
- and
- distinguish the walking state from the non-walking activity state using the computed parallel component of the acceleration signal and using the computed orthogonal component of the acceleration signal;
- and
- a posture calibration circuit configured to use an orientation of the accelerometer in the walking state to perform a posture calibration of the acceleration signal of the accelerometer.
10 more elements
A system comprising:
- a device comprising:
- an accelerometer configured to sense an acceleration signal from a patient;
- a filter circuit configured to extract a characteristic of the acceleration signal;
- a comparison circuit configured to perform a comparison between the characteristic of the acceleration signal and a stored template to distinguish a walking state of the patient from a non-walking activity state of the patient;
- a posture calibration circuit configured to use an orientation of the accelerometer in the walking state to perform a posture calibration of the acceleration signal of the accelerometer;
- and
- a communication circuit configured to receive posture calibration information from the posture calibration circuit;
- and
- an external local interface configured to receive the posture calibration information from the communication circuit.
6 more elements
Dependencies are inferred from the claim text.