Smart Watch Heart Rate Sensing With Motion-Compensated PPG
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Solution Overview
Problem
Smart watches in the related art have low accuracy in measuring heart rate due to the deep burial of blood vessels in the wrist and variations in blood volume, leading to large measurement errors.
Innovation Solution
The smart watch incorporates an optical emitter and receiver to emit and detect light for converting into electrical signals, combined with an accelerometer and gyroscope to obtain motion and angular velocity information, using a PPG algorithm to generate accurate heart rate data and send reminders based on predefined thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensors are used to measure heart rate through blood vessels in the wrist, then heart rate measurement function is provided, but measurement accuracy is low due to deep burial of blood vessels and blood volume variations
Solution Approach 1:
The patent combines multiple sensors (optical emitter, optical receiver, accelerometer, gyroscope) into an integrated measurement system. The optical sensors detect blood volume changes while the motion sensors track user movement, and all data are processed together through the PPG algorithm to compensate for measurement errors caused by blood vessel depth and blood volume variations.
Solution Approach 2:
The patent introduces motion information from accelerometers and gyroscopes as an intermediary factor to compensate for measurement errors. By using the PPG algorithm to process both optical signal data and motion data, the system indirectly compensates for the effects of deep blood vessels and blood volume variations, improving measurement accuracy.
2Measurement precision
If multiple sensors and algorithms are used to improve measurement accuracy, then heart rate measurement precision is enhanced, but device complexity increases
Solution Approach 1:
The patent makes the processor perform multiple functions: it processes optical sensor data for heart rate measurement, processes accelerometer and gyroscope data for motion detection, and executes the PPG algorithm for error compensation. This multi-functionality reduces the need for separate dedicated processing units, thereby managing device complexity while improving measurement precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances heart rate measurement accuracy by utilizing multiple sensors and algorithms to account for user movement, providing precise heart rate information and timely reminders.
Implementation Method 1
an optical receiver configured to receive reflected light, the reflected light being generated by the light emitted by the optical emitter irradiating a skin for conversion into an electrical signal
Data Source
AI summary
The present disclosure provides a smart watch and a method for measuring heart rate information. The smart watch includes an optical emitter configured to emit light; an optical receiver configured to receive reflected light, the reflected light being generated by the light emitted by the optical emitter irradiating a skin for conversion into an electrical signal; an accelerometer sensor configured to detect and obtain motion information of the user; and a processor configured to process the electrical signal to obtain first heart rate information of a user, and generate second heart rate information based on the motion information and the first heart rate information.