Device, system and method for detection and processing of heartbeat signals
Inventors
TOGNETTI, SIMONE • CENCI, IVAN • RESNATI, DANIELE • GARBARINO, MAURIZIO • LAI, MATTEO
Assignees
Publication Number
US-10285602-B2
Publication Date
2019-05-14
Expiration Date
2034-01-21
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Abstract
A heart beat detection device comprises at least one optical reflection sensor to be positioned on the skin of a person. The sensor unit is provided with a light emitter and a corresponding light receiver which converts the light reflected by the skin into an electric signal and comprises electrically adjustable optical filters connected to the emitter, to the receiver or to both of them in order to select, upon operation, a desired light wavelength and perform processing of the signals thus obtained in order to reinforce the heart beat signal. A system with this device and a detection method are also described.
Core Innovation
The invention provides a heart beat detection device comprising at least one optical reflection sensor unit positioned on a person's skin, which includes a light emitter and a corresponding light receiver converting the light reflected by the skin into an electric signal. The device is characterized by electrically adjustable optical filters connected to the emitter, the receiver, or both, allowing dynamic selection of a desired wavelength of the light for emission or reception to improve detection accuracy.
This device addresses the problem of unfavorable signal-to-noise ratios in optical heart rate monitors caused by disturbances such as ambient light, motion artifacts, and mechanical deformation of the skin and underlying tissues. Prior solutions using fixed wavelengths or multiple wavelengths without dynamic tuning have not fully compensated for these disturbances, especially during physical activity or varying skin conditions.
The invention further discloses a system incorporating the device with wireless communication to a data processing and transmission unit, enabling enhanced signal processing. It also outlines a method for increasing the signal-to-noise ratio by differentiating between the effects of multiple wavelengths via adjustable filters and processing signals to reinforce the heart beat pulsation signal. The technology includes combining absorption and fluorescence detection modes, optimizing wavelengths dynamically to adapt to skin properties, and compensating for motion-induced noise via accelerometers and galvanic skin response measurements.
Claims Coverage
The patent discloses multiple inventive features primarily centered on an optical heart beat detection device with adjustable optical filtering, signal processing methods, and enhanced noise reduction. Several independent claims address these features in various configurations.
Electrically adjustable optical filters with Fabry-Perot monochromators
A heart beat detection device including at least one optical reflection sensor unit with electrically adjustable optical filters connected to the emitter, receiver, or both, enabling selection of desired light wavelengths using Fabry-Perot monochromators.
Dual mode detection using absorption and fluorescence principles
A processing block controls the adjustable filters to alternatively select wavelengths for absorption mode and fluorescence mode, processing the corresponding electric signals to obtain an enhanced heart rate signal.
Optimization of emitted light luminosity
A power supply element controlled by a processing block varies the luminosity of the light emitter to maintain the received light level above a predefined minimum threshold, optimizing signal amplitude and battery usage.
Use of two optical sensor units for blood pulse propagation time estimation
Arrangement of two optical sensor units spaced apart, with processing blocks estimating blood pulse propagation time between them and adapting the heart beat signal based on variations in the estimated propagation time to improve noise filtering.
Incorporation of electrical detection measuring skin galvanic response
An electrical detection system measures skin galvanic response. Signals derived from galvanic response related to heart beat are combined with optical signals to further enhance heart rate detection.
Use of acceleration measurement for noise compensation
A system for measuring three-dimensional acceleration of the device is used with adaptive filtering to modify the optical heart beat signal and reduce motion-induced noise.
Methods for dynamic tuning of the electrically adjustable filters
Methods include dynamically adjusting filter wavelengths to maximize signal amplitude in absorption and fluorescence modes, improving detection under varying skin and environmental conditions.
System and method for combining multi-wavelength signals and physiological measurements
Techniques include combining the absorption and fluorescence signals, galvanic skin response, and acceleration data in signal processing to improve robustness and accuracy of heart rate detection.
The claims collectively protect a sophisticated heart beat detection system using dynamically adjustable optical filtering, dual-mode absorption and fluorescence measurement, motion and galvanic response-based noise compensation, and signal processing techniques to optimize heart rate measurement accuracy under varying conditions.
Stated Advantages
Improved signal-to-noise ratio in optical heart beat detection especially under movements and varying skin conditions.
Dynamic tuning of light wavelengths adapts to individual skin properties and environmental factors for optimized measurement.
Combination of absorption and fluorescence detection modes enhances the heart beat signal amplitude.
Use of galvanic skin response and accelerometer signals enables better filtering of noise from mechanical deformation and movement.
Adaptive control of light emission intensity optimizes battery life while maintaining signal quality.
Capability to estimate blood pulse propagation time between two sensors provides additional noise reduction related to tissue movement.
Wireless communication enables remote processing and monitoring, facilitating use in daily activities and prolonged detection periods.
Documented Applications
Detection and monitoring of heart beat signals on various parts of the body, such as the wrist.
Wearable devices for prolonged heart rate monitoring during physical activity and daily life.
Remote physiological monitoring systems communicating heart beat data and other physiological parameters via wireless networks.
Estimating physiological parameters such as stress state, physical activity level, physical condition, sleep quality, and excitation level based on heart rate data.
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