Earbud Accelerometer Alignment for Accurate BCG Signal Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Earbud accelerometers' varying orientations when worn affect the accuracy of biomarker estimates derived from ballistocardiogram (BCG) signals due to misalignment of their axes, compromising signal quality and variability across individuals and measurements.
Innovation Solution
A method to correct the orientation of earbud accelerometers by using calibration techniques, fusion of accelerometer data from separate axes, and integration of multiple sensor inputs to determine optimal alignment, ensuring accurate BCG signal detection and biomarker extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If earbuds are worn in various orientations, then ease of operation and comfort are improved, but measurement precision and signal quality deteriorate due to accelerometer misalignment
Solution Approach 1:
The system dynamically adjusts the accelerometer orientation correction based on detected earbud placement orientation. The correction matrix is computed differently depending on whether the earbuds are worn conventionally or flipped, allowing the system to adapt to various wearing styles while maintaining measurement accuracy.
Solution Approach 2:
The system changes the orientation parameters of the accelerometer through computational correction. By applying different correction matrices based on detected placement orientation, the system transforms the accelerometer readings into a standardized anatomical reference frame, correcting for misalignment without requiring physical repositioning.
2Measurement precision
If accelerometer axes are aligned with body anatomy, then measurement precision is improved, but device complexity increases due to calibration and orientation correction requirements
Solution Approach 1:
The system performs self-calibration by automatically detecting the earbud placement orientation using the accelerometer and gyroscope during normal operation. The orientation correction is computed and applied automatically without requiring manual calibration procedures or user intervention, reducing the complexity burden on the user.
Solution Approach 2:
The system performs preliminary orientation detection and correction matrix computation during the setup phase or when earbuds are first worn. This preliminary action establishes the correct orientation transformation in advance, so that subsequent BCG signal acquisition can proceed using pre-computed corrections, reducing real-time processing complexity.
Data Source
AI summary
In one embodiment, a method includes accessing an accelerometer signal from an accelerometer of an earbud worn by a wearer and determining an orientation adjustment for the accelerometer that corrects accelerometer misalignment of the earbud as worn by the wearer. The method further includes determining, based at least on the orientation adjustment for the accelerometer, an oriented accelerometer signal that represents an accelerometer signal from an optimal orientation of the earbud and determining, from the oriented accelerometer signal, a ballistocardiogram (BCG) signal of the wearer.