Adaptive PPG Sampling for Reliable Irregular Heart Rate Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing PPG sensors struggle to accurately detect irregularities in heart rate signals due to motion artifacts and noise, often failing to distinguish between physiological conditions and noise, and increasing power consumption for improved accuracy can reduce battery life.
Innovation Solution
A PPG sensor unit configured to use a sampling procedure to detect multiple occurrences of a given event in the measured signal, incorporating motion sensors to delay measurements in high-motion states and adjust sensing modes based on power consumption and accuracy needs, using primary and secondary measurements under different conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PPG sensors continuously monitor heart rate signals with high sampling rates to improve detection accuracy, then measurement precision improves, but power consumption increases and battery life decreases
Solution Approach 1:
The patent implements periodic sampling of heart rate signals at varying rates based on detected motion states. During low-motion periods, higher sampling rates are used to capture potential arrhythmias, while during high-motion periods, sampling is reduced or paused to conserve power. This periodic adaptation resolves the contradiction by dynamically adjusting measurement frequency to match actual detection needs.
Solution Approach 2:
The system dynamically adjusts sampling parameters based on real-time motion detection feedback. Motion sensors detect activity levels, and the PPG sampling rate is adaptively modified accordingly. This dynamic adjustment allows the system to maintain high measurement precision when needed while minimizing power consumption during periods when accurate detection is less critical.
2Reliability
If PPG sensors increase sampling frequency and measurement duration to detect irregular heart rate patterns, then detection reliability improves, but power consumption increases
Solution Approach 1:
The system performs preliminary motion assessment before initiating extended PPG sampling sequences. Motion sensors evaluate current activity levels, and only when low motion is detected does the system proceed with prolonged high-frequency sampling to detect irregularities. This preliminary gating action ensures reliable detection is pursued only when conditions favor it, avoiding unnecessary power expenditure.
Solution Approach 2:
The system uses feedback from motion sensors to continuously monitor sampling conditions and adjust measurement parameters. When motion exceeds thresholds, sampling is reduced; when motion is low, sampling intensity increases to improve detection reliability. This feedback loop ensures the system maintains detection reliability while minimizing power consumption by adapting to real-time conditions.
3Productivity
If PPG sensors perform measurements during high-motion states to capture all potential irregularities, then detection completeness improves, but measurement precision deteriorates due to motion artifacts
Solution Approach 1:
The system extracts and separates motion artifact signals from the PPG signal using motion sensor data. By identifying portions of the PPG signal that correlate with detected motion, the system can exclude or correct these artifact-contaminated segments. This extraction approach allows the system to maintain detection coverage while preserving measurement precision by focusing analysis on clean, artifact-free signal portions.
Solution Approach 2:
Before performing PPG measurements, the system preliminarily assesses motion levels using motion sensors. When high motion is detected, the system either delays measurements or applies motion correction algorithms to compensate for artifacts. This preliminary motion evaluation enables the system to maintain detection coverage while ensuring measurement precision by avoiding or correcting artifact-contaminated data.
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 measurement accuracy by reducing noise interference and optimizing power usage, allowing for reliable detection of irregular heart rate patterns while conserving battery life.
Implementation Method 1
the light source(s) can emit light to illuminate the user's skin. The light detector(s) can measure light incident on the light detectors to be used to determine the amount of light from the light source(s) that reaches the detector(s)... The amount of light measured by the light detectors can vary based on the amount of light absorbed by the tissue of the user
Implementation Method 2
The light detector(s) can convert the measured light into an electrical signal indicative of the intensity thereof
Data Source
AI summary
This relates to methods for measuring irregularities in a signal and corresponding devices. The devices can include a PPG sensor unit configured to detect multiple occurrences of a given event in the measured signal(s) over a sampling interval. In some instances, the device can register the occurrences of the events. In some examples, the device can include one or more motion sensors configured to detect whether the device is in a low-motion state. The device may delay initiating measurements when the device is not in a low-motion state to enhance measurement accuracy. Examples of the disclosure further include resetting the sample procedure based on one or more factors such as the number of non-qualifying measurements. In some examples, the device can be configured to perform both primary and secondary measurements, where the primary measurements can include readings using a set of operating conditions different from the secondary measurements.