Heart Rate Estimation Using Motion Sensor Noise Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional cardiovascular measurements, such as heart rate determination using optical sensors, are often affected by user movement, leading to noise and inaccuracies due to the sensitivity of these measurements to subtle movements.
Innovation Solution
A method that combines optical sensor signals with motion sensor signals for noise reduction, employing spectral analysis to identify a fundamental frequency and estimate heart rate, while also generating quality metrics to assess the reliability of the measurement process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensor measurements are used to obtain cardiovascular parameters, then biometric information can be obtained, but the measurements become sensitive to user movement and introduce noise
Solution Approach 1:
The patent combines optical sensor signals with motion sensor signals through signal processing. The motion sensor data is used to identify and remove motion-related artifacts from the optical sensor signal, thereby improving measurement reliability during user movement while maintaining measurement precision.
Solution Approach 2:
The motion sensor acts as an intermediary that provides information about user movement. This intermediary data is used to characterize and compensate for motion-induced noise in the optical sensor measurements, allowing the system to distinguish between physiological signals and motion artifacts.
2Reliability
If motion compensation techniques are applied to reduce noise, then measurement reliability improves, but device complexity increases
Solution Approach 1:
The patent extracts motion-related components from the optical sensor signal by comparing it with motion sensor data. By identifying and removing only the motion-induced artifacts rather than processing the entire signal complexly, the system improves reliability while keeping the processing complexity manageable.
Solution Approach 2:
The system changes parameters of the optical sensor signal based on motion sensor data. By adjusting signal processing parameters dynamically according to motion levels, the system achieves improved reliability during motion without requiring overly complex processing algorithms for all conditions.
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
This approach improves the accuracy and reliability of cardiovascular parameter measurements by compensating for motion-induced noise, providing a more robust estimation of heart rate and confidence metrics.
Implementation Method 1
a photoplethysmogram (PPG) sensor obtains volumetric measurements of blood vessels near the skin surface. When the heart pumps blood, the resulting pressure pulse causes changes to blood vessels. The pressure pulse may distend arteries and arterioles in skin tissue. An optical sensor, such as a PPG sensor, may be used to detect a change in blood vessel volume caused by the pressure pulse.
Implementation Method 2
Blood vessel volume change caused by the pressure pulse is detected by illuminating the skin with the light from a light-emitting diode (LED) and then measuring the amount of light either transmitted or reflected to a photodiode.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Disclosed embodiments pertain to the measurement of heart rate in the presence of motion and noise. Spectral peaks in measurements by an optical sensor are compared with spectral peaks obtained from a motion sensor signal measurements, to obtain a fundamental frequency in the optical sensor signal, where the fundamental frequency is associated with a user's heart rate. A first heart rate may be estimated based on the fundamental frequency. A variety of quality metrics may be determined for the first heart rate estimate. A second estimated heart rate may be determined based by processing a frequency domain representation of the optical sensor signal based on a frequency domain representation of the motion sensor signal. One or more of the previously determined quality metrics may be dynamically adjusted based on a comparison of first and second estimated heart rates.