Biometric Detection Module with Frequency Domain Noise Filtering
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Solution Overview
Problem
Conventional pulse oximeters face challenges in accurately detecting biometric characteristics like blood oxygenation and heart rate when the body is in a non-static state, due to movement causing disturbed signals and noise in the detected intensity variations of light penetrating through body tissues.
Innovation Solution
A biometric detection device with a light source module emitting green, red, and infrared light in a time division manner, a detection unit with an abrasion-proof layer, and a processor that converts these signals to the frequency domain to determine filtering parameters, filters the signals, and calculates biometric characteristics, effectively reducing noise and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pulse oximeters detect light intensity variations to measure blood oxygenation and heart rate, then blood oxygenation and heart rate monitoring is achieved, but movement of the body parts causes disturbed signals and noise that prevent accurate calculation of physiology information
Solution Approach 1:
The patent segments the detection process into multiple wavelength channels (red and infrared) and processes each channel's signal separately through frequency domain transformation. This allows independent filtering and noise removal for each wavelength, improving the reliability of blood oxygenation calculation by eliminating movement-induced disturbances from each signal component before combining them.
Solution Approach 2:
The patent introduces frequency domain transformation as an intermediary processing step between light detection and physiological parameter calculation. By converting time-domain light intensity signals into frequency domain representations, the system can identify and remove noise components caused by body movement, thereby obtaining cleaner signals for accurate biometric characteristic determination.
2Ease of operation
If the detection region is exposed to detect light signals, then light intensity variations can be detected, but the detection region is vulnerable to abrasion and damage
Solution Approach 1:
The patent applies a protective layer covering the detection region that acts as a flexible barrier against abrasion and physical damage. This thin film structure allows the detection region to remain exposed enough to detect light signals while providing necessary mechanical protection, thus maintaining detection capability while improving durability and abrasion resistance.
3Measurement precision
If multiple wavelengths of light are used to calculate blood oxygenation, then accurate blood oxygenation measurement is achieved, but the system complexity increases
Solution Approach 1:
The patent replaces complex time-domain signal processing methods with frequency domain transformation techniques. This substitution simplifies the processing of multiple wavelength signals by transforming them into frequency representations where noise and physiological signals can be more easily separated and filtered, thereby maintaining measurement precision while reducing overall system complexity.
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 enables accurate detection of biometric characteristics even in non-static states by filtering out noise from the frequency domain signals, enhancing the reliability of blood oxygenation and heart rate monitoring.
Implementation Method 1
The light source module is configured to emit green light, red light and infrared light in a time division manner to illuminate the skin region
Implementation Method 2
The detection region is configured to detect penetrating light emitted from the light source module for illuminating the skin region and passing through body tissues to correspondingly generate a green light signal, a red light signal and an infrared light signal
Implementation Method 3
The abrasion-proof layer covers the detection region and has an upper surface as a detection surface, wherein a thickness of the abrasion-proof layer is smaller than 100 micrometers, and the upper surface is configured to be in contact with the skin region when detecting the biometric characteristic such that the light emitted from the light source module illuminates the skin region and sequentially passes through the body tissues and the abrasion-proof layer to be detected by the detection region
Implementation Method 4
The processor of the earphone is configured to convert the green light signal to frequency domain to determine a filtering parameter according to a frequency domain green light signal, respectively convert the red light signal and the infrared light signal to a frequency domain red light signal and a frequency domain infrared light signal
Implementation Method 5
filter the frequency domain red light signal and the frequency domain infrared light signal using the filtering parameter determined from the frequency domain green light signal, to obtain a filtered red light signal and a filtered infrared light signal
Data Source
AI summary
A biometric detection module including a light source module, a detection region and a control module is provided. The light source module is configured to emit green light, red light and IR light in a time division manner to illuminate a skin surface. The detection region is configured to detect penetration light emitted from the light source module for illuminating the skin surface and passing through body tissues to correspondingly generate a green light signal, a red light signal and an IR light signal. The control module is configured to determine a filtering parameter according to the green light signal to accordingly filter the red light signal and the IR light signal, and calculate a biometric characteristic according to at least one of the green light signal, a filtered red light signal and a filtered IR light signal.