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-9833155-B2
Publication Date
2017-12-05
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 opt cal 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 relates to an innovative heart beat detection device comprising at least one optical reflection sensor unit configured to be placed on a person's skin. This sensor unit includes a light emitter and a corresponding light receiver which converts 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 to both, enabling dynamic selection of a desired light wavelength to reinforce the heart beat signal. The device may also include a processing block for controlling the optical filters and processing the signals, thereby improving detection.
The invention also provides a system incorporating this device, where at least one device is connected via a wireless interface to a data processing and transmission unit that processes the physiological data. The system may further communicate with remote terminals or servers for data management and display. Methods for increasing the signal/noise ratio include differentiating effects of at least two light wavelengths through electrically adjustable optical filters and processing the corresponding signals using absorption and fluorescence modes.
The problem addressed by the invention is the disturbance and noise affecting optical heart beat detection systems, especially those using reflection sensors placed on practical body zones like the wrist. Such disturbances arise from ambient light conditions, relative movement between sensor and tissues, and mechanical deformation of the skin, which corrupt the measurement signal. Known solutions—such as using movement sensors or dual wavelength light sources—provide limited improvements and do not achieve a satisfactory signal/noise ratio during various activities or conditions. The invention aims to provide a system ensuring reliable heart beat detection even with these challenges.
Claims Coverage
The patent claims include eight independent claims covering a heart beat detection device, a system for detecting physiological data, and a method for increasing signal/noise ratio.
Electrically adjustable optical filters in heart beat detection device
The device comprises at least one optical sensor unit including a light emitter and corresponding receiver, with electrically adjustable optical filters (including Fabry-Perot monochromators) connected to the emitter, receiver, or both, configured to select a desired wavelength dynamically for optimizing heart beat signal detection.
Dual mode measurement using absorption and fluorescence principles
A processing block selects between a first mode measuring signals based on absorption and a second mode measuring signals based on fluorescence, processing either to generate a heart rate signal.
Optimization of received light signal amplitude
The device includes a processing block controlling the optical filters to optimize the amplitude of the received light signal to improve detection quality.
Dual optical sensor units for blood propagation time estimation
Two optical sensor units arranged at a fixed distance provide phase-shifted signals; a processing block estimates blood propagation time between them and modifies signals based on this to reduce noise from tissue movement.
Incorporation of galvanic skin response measurement
An electrical detection system measures the galvanic response of the skin, combined with the optical signals by a processing block to generate an enhanced heart beat signal.
Use of acceleration data for noise reduction
The device includes an acceleration measurement system; the processing block modifies optical signals based on measured acceleration to compensate for motion-induced noise.
Dynamic control of emitter luminosity to maintain signal threshold
A power supply element varies the light emitter's luminosity commanded by the processing block to keep the detected light signal above a predefined minimum, optimizing battery use and signal quality.
System for wireless communication and remote processing
A system comprising at least one such device connected wirelessly to a data processing unit that can communicate with remote terminals or the Internet and can include wrist-mounted devices paired with smart phones or tablets for processing and transmission of physiological data.
Method for enhancing signal/noise ratio using selectable wavelengths and adaptive filtering
The method differentiates between at least two wavelengths associated with absorption and fluorescence modes using electrically adjustable optical filters, dynamically tuning wavelengths for maximal signal, applying adaptive numerical filters to process signals, subtract acceleration signals, estimate blood propagation time when using multiple sensors, and combine galvanic skin response for improved heart beat detection.
The claims constitute inventive features relating to a heart beat detection device with electrically adjustable optical filters enabling dynamic wavelength selection, dual-mode optical measurement using absorption and fluorescence, signal optimization strategies including multiple sensors for propagation time estimation, galvanic skin response integration, motion compensation via accelerometers, and adaptive emission control. These are complemented by systems enabling wireless communication and sophisticated signal processing methods to increase measurement accuracy and reduce noise.
Stated Advantages
Improved signal/noise ratio of heart beat detection by dynamically selecting wavelengths using electrically adjustable optical filters.
Capability to operate in both absorption and fluorescence modes to leverage different physiological light interactions.
Adaptive tuning of optical filters and emitter luminosity enhances signal amplitude and battery efficiency.
Use of dual sensors and estimation of blood propagation time enables compensation for tissue movement noise.
Integration of galvanic skin response measurement further improves heart beat signal quality.
Incorporation of accelerometer data allows compensation for motion artifacts and noise reduction during dynamic activities.
Wireless communication and remote processing facilitate real-time monitoring and data transmission to external devices or servers for further analysis and display.
Documented Applications
Wearable heart rate monitoring devices positioned on the wrist, similar in form to wrist-watches or bracelets, for continuous heart beat detection.
Remote physiological monitoring systems where data collected by optical sensors are sent wirelessly to processing units and then to remote terminals or servers for examination by operators.
Portable devices paired with smartphones or tablets enabling local processing, display, and transmission of physiological data.
Applications in stress monitoring, assessment of physical activity and condition, quality of sleep, and excitation level estimation based on derived physiological parameters from the heart beat signals.
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