Methods for reducing noise in optical biological sensors
First Claim
1. A method comprising:
- detecting, by at least one optical detector of a medical diagnostic device, a first optical signal transmitted through a skin surface from within a first portion of a lumen of subsurface vasculature, wherein the first optical signal comprises an unfiltered target signal and a first noise signal;
detecting, by the at least one optical detector of the device, a second optical signal transmitted through the skin surface from within a second portion of the lumen of the subsurface vasculature, wherein the second optical signal comprises a second noise signal, and wherein the first and second noise signals are correlated and wherein a quotient of the unfiltered target signal and the first noise signal comprises an unfiltered signal to noise ratio; and
determining a filtered signal, based at least on the unfiltered target signal, the first noise signal, and the second noise signal, wherein the filtered signal comprises a filtered target signal and a filtered noise signal, wherein a quotient of the filtered target signal and the filtered noise signal comprises a filtered signal to noise ratio, wherein determining the filtered signal based at least on the unfiltered target signal, the first noise signal, and the second noise signal comprises determining the filtered signal such that the filtered signal to noise ratio is higher than the unfiltered signal to noise ratio.
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Accused Products
Abstract
Optical measurement of physiological parameters with wearable devices often includes measuring signals in the presence of significant noise sources. These noise sources include, but are not limited to, noise associated with: variable optical coupling to skin or tissue, variations in tissue optical properties with time due to changes in humidity, temperature, hydration, variations in tissue optical properties between individuals, variable coupling of ambient light sources into detectors, and instrument and detector noise, including electrical noise, radio frequency or magnetic interference, or noise caused by mechanical movement of the detector or its components. The present disclosure includes devices and methods configured to produce representations of the raw data in which noise, broadly defined, is separated from the data of interest. The disclosed devices and methods may include subtracting or calibrating out these noise sources and other spurious fluctuations in wearable devices with optical sensors.
33 Citations
14 Claims
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1. A method comprising:
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detecting, by at least one optical detector of a medical diagnostic device, a first optical signal transmitted through a skin surface from within a first portion of a lumen of subsurface vasculature, wherein the first optical signal comprises an unfiltered target signal and a first noise signal; detecting, by the at least one optical detector of the device, a second optical signal transmitted through the skin surface from within a second portion of the lumen of the subsurface vasculature, wherein the second optical signal comprises a second noise signal, and wherein the first and second noise signals are correlated and wherein a quotient of the unfiltered target signal and the first noise signal comprises an unfiltered signal to noise ratio; and determining a filtered signal, based at least on the unfiltered target signal, the first noise signal, and the second noise signal, wherein the filtered signal comprises a filtered target signal and a filtered noise signal, wherein a quotient of the filtered target signal and the filtered noise signal comprises a filtered signal to noise ratio, wherein determining the filtered signal based at least on the unfiltered target signal, the first noise signal, and the second noise signal comprises determining the filtered signal such that the filtered signal to noise ratio is higher than the unfiltered signal to noise ratio. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A medical diagnostic device, comprising:
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at least one optical detector configured to detect an unfiltered target signal, a first noise signal, and a second noise signal, wherein the unfiltered target signal and first noise signal are transmitted through a skin surface from within a first portion of a lumen of subsurface vasculature, wherein the second noise signal is transmitted through the skin surface from within a second portion of the lumen of subsurface vasculature, wherein the first and second noise signals are correlated, and wherein a quotient of the unfiltered target signal and the first noise signal comprises an unfiltered signal to noise ratio; and a computing device configured to; determine a filtered signal, based at least on the unfiltered target signal, the first noise signal, and the second noise signal, wherein the filtered signal comprises a filtered target signal and a filtered noise signal, and wherein a quotient of the filtered target signal and the filtered noise signal comprises a filtered signal to noise ratio, wherein determining the filtered signal based at least on the unfiltered target signal, the first noise signal, and the second noise signal comprises determining the filtered signal such that the filtered signal to noise ratio is higher than the unfiltered signal to noise ratio. - View Dependent Claims (8, 9, 10)
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11. A non-transitory computer readable medium having stored therein instructions executable by a computing device to cause the computing device to perform operations comprising:
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detecting, by at least one optical detector in a medical diagnostic device, a first optical signal transmitted through a skin surface from within a first portion of a lumen of subsurface vasculature and a second optical signal transmitted through the skin surface from within a second portion of the lumen of subsurface vasculature, wherein the first optical signal comprises an unfiltered target signal and a first noise signal and the second optical signal comprises a second noise signal, wherein the first and second noise signals are correlated and wherein a quotient of the unfiltered target signal and the first noise signal comprises an unfiltered signal to noise ratio; and determining a filtered signal, based at least on the unfiltered target signal, the first noise signal, and the second noise signal, wherein the filtered signal comprises a filtered target signal and a filtered noise signal, and wherein a quotient of the filtered target signal and the filtered noise signal comprises a filtered signal to noise ratio, wherein determining the filtered signal based at least on the unfiltered target signal, the first noise signal, and the second noise signal comprises determining the filtered signal such that the filtered signal to noise ratio is higher than the unfiltered signal to noise ratio. - View Dependent Claims (12, 13, 14)
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Specification