Non-invasive flow monitoring
First Claim
1. A device comprising:
- a light source, wherein the light source is configured to emit a beam of coherent illumination into a portion of subsurface vasculature;
a volume holographic grating optically coupled to the light source, wherein the volume holographic grating is configured to increase a coherence length of the beam of coherent illumination emitted by the light source;
a light sensor, wherein the light sensor detects a pattern of constructive and destructive interference in light emitted from the portion of subsurface vasculature in response to the coherent illumination from the light source and outputs a detected light intensity waveform comprising a plurality of pulses corresponding to speckle events caused by motion of one or more individual particles in the subsurface vasculature, wherein each pulse in the plurality of pulses includes a respective rising edge, plateau, and falling edge; and
a controller coupled to the light source and the light sensor, wherein the controller comprises an analog frontend that processes the output of the light sensor, wherein the analog frontend comprises a differentiator configured to output a signal indicative of a rate of increase during a rising edge of each respective pulse, and wherein the controller (i) determines velocities of the one or more individual particles based on the output of the differentiator, and (ii) determines a flow property of fluid in the portion of subsurface vasculature based on the determined velocities of the one or more individual particles.
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0 Petitions
Accused Products
Abstract
Systems are provided for detecting the flow of blood in vasculature by illuminating the blood with a source of coherent illumination and detecting one or more time-varying properties of a light speckle pattern that results from the scattering of the coherent illumination by tissue and blood. The movement of blood cells and other light-scattering elements in the blood causes transient, short-duration changes in the speckle pattern. High-frequency sampling or other high-bandwidth processing of a detected intensity at one or more points in the speckle pattern could be used to determine the flow of blood in the vasculature. Such flow-measuring systems are also presented as wearable devices that can be operated to detect the flow in vasculature of a wearer. Systems and methods provided herein can additionally be applied to measure flow in other scattering fluid media, for example in a scattering industrial, medical, pharmaceutical, or environmental fluid.
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Citations
12 Claims
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1. A device comprising:
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a light source, wherein the light source is configured to emit a beam of coherent illumination into a portion of subsurface vasculature; a volume holographic grating optically coupled to the light source, wherein the volume holographic grating is configured to increase a coherence length of the beam of coherent illumination emitted by the light source; a light sensor, wherein the light sensor detects a pattern of constructive and destructive interference in light emitted from the portion of subsurface vasculature in response to the coherent illumination from the light source and outputs a detected light intensity waveform comprising a plurality of pulses corresponding to speckle events caused by motion of one or more individual particles in the subsurface vasculature, wherein each pulse in the plurality of pulses includes a respective rising edge, plateau, and falling edge; and a controller coupled to the light source and the light sensor, wherein the controller comprises an analog frontend that processes the output of the light sensor, wherein the analog frontend comprises a differentiator configured to output a signal indicative of a rate of increase during a rising edge of each respective pulse, and wherein the controller (i) determines velocities of the one or more individual particles based on the output of the differentiator, and (ii) determines a flow property of fluid in the portion of subsurface vasculature based on the determined velocities of the one or more individual particles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification