Wearable PPG Sensor Frequency Domain Hemoglobin Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wearable devices for monitoring hemoglobin concentration and blood oxygen saturation are limited by low accuracy, sensitivity to motion artifacts, and inability to operate effectively in reflection mode, making them unsuitable for continuous, non-invasive, and reliable monitoring.
Innovation Solution
A wearable device equipped with a photoplethysmographic (PPG) sensor that irradiates tissue with multiple wavelengths, transforms PPG signals from the time domain to the frequency domain, and analyzes amplitude-phase characteristics of harmonics to determine hemoglobin concentration using a database and machine learning algorithms, while filtering out motion artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional PPG sensors are used in wearable devices for hemoglobin monitoring, then the device structure is simple and easy to manufacture, but the measurement accuracy is low and the device is sensitive to motion artifacts
Solution Approach 1:
The patent transforms PPG signals from the time domain to the frequency domain by changing the parameter of signal representation. This transformation enables the extraction of amplitude-phase characteristics of harmonics, which provides more information for determining hemoglobin concentration and improves measurement accuracy while managing the complexity through systematic signal processing
Solution Approach 2:
The patent replaces traditional time-domain signal analysis with frequency-domain analysis using amplitude-phase characteristics of harmonics. This substitution of analysis methodology enables more accurate hemoglobin determination by capturing additional signal features that are not apparent in the time domain
2Reliability
If traditional PPG signal analysis methods are used, then the processing is simple and fast, but the device cannot effectively filter motion artifacts and operates poorly in reflection mode
Solution Approach 1:
The patent changes the domain parameter from time to frequency, which enables the system to filter motion artifacts more effectively. By analyzing the amplitude-phase characteristics of harmonics in the frequency domain, the system can distinguish between physiological signals and motion-induced artifacts, improving reliability while the structured approach manages computational complexity
Solution Approach 2:
The frequency domain transformation acts as an intermediary that separates the desired physiological information from motion artifacts. By transforming the signal and analyzing harmonic characteristics, the system can identify and filter out motion-related components while preserving the physiological signal, thereby improving motion artifact resistance
3Measurement precision
If multiple wavelengths are used for PPG measurement, then the hemoglobin determination accuracy improves, but the device complexity and energy consumption increase
Solution Approach 1:
The patent uses multiple wavelengths of light for PPG measurement, where each wavelength provides complementary information about hemoglobin concentration. The frequency domain analysis methodology processes signals from multiple wavelengths efficiently, enabling accurate hemoglobin determination while managing energy consumption through optimized signal processing
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
The solution provides high-accuracy, motion-resistant, and continuous monitoring of hemoglobin concentration and blood oxygen saturation, suitable for non-professional use, improving upon existing limitations by analyzing PPG signals in the frequency domain and using machine learning for precise hemoglobin determination.
Implementation Method 1
detect at least two PPG signals at the at least two different wavelengths in a reflection mode
Implementation Method 2
transform the at least two PPG signals from a time domain to a frequency domain or time-frequency domain
Data Source
AI summary
A wearable device and a method for determining a hemoglobin concentration in a user's blood are provided. The method includes irradiating a tissue of a user with radiation of at least two different wavelengths, detecting photoplethysmographic (PPG) signals from the user's tissue in a time domain at the at least two different wavelengths in a reflection mode, transforming the detected PPG signals from the time domain to a frequency domain or a time-frequency domain, describing the transformed PPG signals with respect to harmonics to obtain a set of characteristics, and determining a hemoglobin concentration in the user's blood based on the obtained set of characteristics and an information from a database.