PPG Heartbeat Profile Extraction with Baseline Correction
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Solution Overview
Problem
Photoplethysmography (PPG) data is often noisy due to sloping baselines and baseline shifts, making it difficult to accurately segment heartbeat cycles and perform reliable biometric monitoring.
Innovation Solution
A method and device for generating a baseline corrected heartbeat profile by determining end-of-phase information, calculating baseline correction points, and applying principal component analysis (PCA) to correct sloping baselines and shifts across multiple wavelength channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PPG data is collected from multiple wavelength channels to improve measurement comprehensiveness, then the ability to perform biometric monitoring is enhanced, but baseline noise and sloping baselines increase making segmentation difficult
Solution Approach 1:
The patent segments the PPG signal processing into distinct stages: (1) detecting peak points and trough points in each wavelength channel, (2) calculating baseline correction points based on these extrema, (3) performing baseline correction to remove sloping baselines, and (4) segmenting heartbeat cycles using the corrected signal. This systematic segmentation allows effective noise removal while preserving the multi-wavelength information needed for reliable biometric monitoring.
Solution Approach 2:
The patent transforms the raw PPG signal parameters by calculating baseline correction points derived from peak and trough positions, then applies parameter changes through baseline correction to remove sloping baselines. This parameter transformation converts the noisy multi-wavelength signal into a corrected signal suitable for accurate heartbeat segmentation and biometric analysis.
2Measurement precision
If baseline correction is applied to remove sloping baselines, then heartbeat cycle segmentation accuracy improves, but processing complexity increases
Solution Approach 1:
The patent performs preliminary detection of peak points and trough points before baseline correction, using these detected extrema to calculate baseline correction points in advance. This preliminary action simplifies the subsequent baseline correction process by providing predetermined reference points, reducing the overall processing complexity while maintaining segmentation accuracy.
Solution Approach 2:
The baseline correction process uses self-service by automatically deriving correction points from the signal's own peak and trough features. The algorithm identifies extrema within the signal itself and uses these inherent characteristics to generate baseline correction points, eliminating the need for external reference signals or complex manual calibration procedures.
3Measurement precision
If end-of-phase information is used to calculate baseline correction points, then baseline correction accuracy improves, but the computational steps increase
Solution Approach 1:
The patent extracts end-of-phase information (peak and trough points) from the PPG signal as distinct features, separating these critical reference points from the rest of the signal processing. By extracting and utilizing only these essential phase transition points for baseline correction, the method achieves high accuracy while avoiding unnecessary computational steps from processing the entire signal waveform.
Data Source
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AI summary
A device may determine end-of-phase information for a plurality of wavelength channels of photoplethysmography (PPG) data. The device may calculate a set of baseline correction points for each wavelength channel of the plurality of wavelength channels. The set of baseline correction points may be calculated based on end-of-phase information for a wavelength channel of the plurality of wavelength channels and PPG data associated with the wavelength channel. The device may perform a baseline correction for each wavelength channel of the plurality of wavelength channels. A baseline correction may be performed for the wavelength channel based on the set of baseline correction points associated with the wavelength channel and the PPG data associated with the wavelength channel. The device may generate a baseline corrected heartbeat profile using a principal component analysis of a result of baseline correcting each wavelength channel of the plurality of wavelength channels.