Optical Vital Signs Sensor Dynamic Sampling Adaptation
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Solution Overview
Problem
Existing optical vital signs sensors face challenges in maintaining accurate detection of vital signs when not in direct contact with the skin, as changes in sampling frequency or number of pulses per sample can disrupt signal quality.
Innovation Solution
An optical vital signs sensor with a PPG sensor, pre-processing unit, and sensor control unit that adjusts sampling frequency and number of pulses per sample to neutralize changes, ensuring a stable signal-to-noise ratio and maintaining accurate vital sign detection through a scalable and down-sampling mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the sampling frequency or number of pulses per sample is changed to adapt to different activity levels, then the sensor can handle varying signal conditions, but the signal quality and consistency deteriorate due to frequency variations
Solution Approach 1:
The patent implements dynamic sampling frequency adaptation where the control unit adjusts the sampling frequency based on detected signal quality and user activity level. The system transitions from fixed to dynamic sampling rates, allowing optimal signal acquisition across varying conditions while maintaining reliability through real-time parameter adjustment.
Solution Approach 2:
The system changes the sampling frequency parameter dynamically based on signal characteristics and activity detection. By modifying this key parameter in response to changing conditions, the sensor maintains optimal performance across different activity levels while the pre-processing unit compensates for the changes to preserve signal quality.
2Measurement precision
If the sampling frequency is increased to capture faster changes in vital signs, then the detection accuracy improves, but the data processing complexity and computational load increase
Solution Approach 1:
The system applies partial sampling by adjusting the sampling frequency to match the actual signal characteristics rather than using maximum sampling rates continuously. The control unit determines appropriate sampling levels based on activity detection, applying only the necessary sampling intensity to maintain precision while reducing unnecessary processing complexity.
Solution Approach 2:
The sampling frequency is dynamically adjusted based on detected activity levels and signal characteristics. During low-activity periods, lower sampling rates are used to reduce processing load, while during high-activity or arrhythmia detection, the system increases sampling frequency to maintain measurement precision, thus balancing both precision and complexity.
3Reliability
If the number of pulses per sample is increased to improve signal-to-noise ratio, then the signal quality improves, but the sampling rate decreases reducing the temporal resolution
Solution Approach 1:
The system dynamically balances the number of pulses per sample against sampling rate based on activity detection and signal quality requirements. The control unit adjusts these parameters in real-time, increasing pulses per sample when signal quality is poor and maintaining higher sampling rates when temporal resolution is critical, thus optimizing both signal-to-noise ratio and sampling speed adaptively.
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
Enables improved and non-invasive monitoring of vital signs by stabilizing the output signal, allowing for reliable detection of heart rate, blood volume, and blood compounds even when contact is lost, by dynamically adapting sampling parameters to meet signal requirements.
Implementation Method 1
The emitted light is scattered in the skin and is at least partially absorbed by the blood
Implementation Method 2
The emitted light is scattered in the skin and is at least partially absorbed by the blood
Implementation Method 3
Such a heart rate sensor can be based on a photoplethysmograph (PPG) sensor and can be used to acquire a volumetric organ measurement
Data Source
AI summary
An optical vital signs sensor is provided which comprises a PPG sensor (100), a pre-processing unit (130) which adapts the sampling rate or the number of pulses per sample, a processing unit (140) which executes at least one processing algorithm based on an output signal of the pre-processing unit and a sensor control unit (150). The sensor control unit is configured to control the PPG sensor by adapting the sampling rate and/or the number of pulses per sample.