LOW FREQUENCY NOISE IMPROVEMENT IN PLETHYSMOGRAPHY MEASUREMENT SYSTEMS
First Claim
1. A system comprising:
- a radiation source;
a first sensor for generating a first signal in response to a portion of radiation from the source returned from the subject; and
an auxiliary sensor for detecting a second portion of radiation from the source through a direct path from the source to the auxiliary sensor.
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Accused Products
Abstract
A plethysmography (“PPG”) measurement system may include at least one source of PPG radiation and at least one auxiliary sensor for detection of PPG radiation. The radiation source emits a portion of the PPG radiation toward a subject and another portion along an optical path for direct communication between the PPG radiation source and the auxiliary sensor. The auxiliary sensor may develop a profile against which measurements from primary PPG sensors, which receive light returning from the subject, may be compared. From this comparison, new PPG signals may be generated that exhibit lower noise than the PPG signals output by PPG sensors. These noise mitigation techniques may be used advantageously by a PPG system to generate more accurate measurements and also to reduce power consumption by the radiation sources.
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Citations
35 Claims
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1. A system comprising:
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a radiation source; a first sensor for generating a first signal in response to a portion of radiation from the source returned from the subject; and an auxiliary sensor for detecting a second portion of radiation from the source through a direct path from the source to the auxiliary sensor. - View Dependent Claims (2, 3, 4, 5)
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6. A method comprising:
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illuminating a subject with a radiation source; measuring, by a first sensor, a portion of the radiation returned from the subject; generating a first signal based on the measurement by the first sensor; measuring a portion of the radiation by an auxiliary sensor via an optical path between the radiation source and the auxiliary sensor that does not traverse the subject; generating a second signal based the measurement by the auxiliary sensor; and modifying the first signal based on the second signal. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. A sensor system, comprising:
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a source of photoplethysmographic (PPG) radiation, a sensor for detection of PPG radiation, and a housing that accommodates the source and the sensor that defines an aperture for emission of a portion of the PPG radiation toward a subject and an optical path for direct communication of another portion of the PPG radiation from the source to the sensor. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A system, comprising:
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a photoplethysmographic (PPG) measurement system including; a source of PPG radiation; a pair of sensors for detecting PPG radiation, a first sensor to detect PPG radiation that traverses a test subject and a second sensor to detect PPG radiation from the source along an optical path that does not traverse the subject; and a processor operative to; manage operation of the system; receive signals based output signals from the pair of sensors; and apply noise management logic to the signals, wherein the noise management logic includes algorithms based on the outputs from the pair of sensors. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35)
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Specification