CMOS Sensor Array Heart Rate Detection Motion Interference
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Solution Overview
Problem
Current PPG systems have insufficient dynamic range due to single pixel usage, leading to high signal-to-noise ratio and decreased detection accuracy for heart rate monitoring.
Innovation Solution
A heart rate detecting module utilizing a CMOS sensor array and a processor to generate displacement information of light intensity gravity centers and calculate light intensity variance, thereby achieving a broad dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pixel is used in the PPG system, then the device complexity is reduced, but the dynamic range becomes insufficient leading to high signal-to-noise ratio
Solution Approach 1:
The patent divides the detection function into multiple pixels (first pixel and second pixel) with different functions. The first pixel detects light at a first wavelength while the second pixel detects light at a second wavelength, allowing each pixel to be optimized for its specific detection task and collectively providing sufficient dynamic range without excessive complexity
Solution Approach 2:
The patent introduces a new dimension by using multiple pixels with different spectral response characteristics (different wavelengths) rather than relying on a single pixel. This multi-dimensional approach to light detection expands the system's dynamic range capability while maintaining manageable device complexity
2Ease of manufacture
If a single pixel is used in the PPG system, then the manufacturing cost is reduced, but the signal-to-noise ratio increases decreasing detection accuracy
Solution Approach 1:
The patent segments the detection function across multiple pixels with specialized roles. The first pixel is optimized for detecting light at a first wavelength while the second pixel detects light at a second wavelength, allowing cost-effective manufacturing of specialized photodetectors rather than requiring a single high-performance pixel
Solution Approach 2:
The patent applies local quality by giving different pixels different spectral sensitivities tailored to their specific detection needs. The first pixel has optimized sensitivity for the first wavelength while the second pixel has optimized sensitivity for the second wavelength, improving overall signal-to-noise ratio without requiring all pixels to be expensive high-performance detectors
3Measurement precision
If multiple pixels with different wavelengths are used, then the dynamic range is improved, but the device complexity increases
Solution Approach 1:
The patent segments the spectral detection range across multiple pixels, with each pixel dedicated to detecting light at a specific wavelength. This functional segmentation allows the system to achieve broad dynamic range coverage while keeping each individual pixel relatively simple, balancing measurement precision with device complexity
Solution Approach 2:
The patent implements multi-functionality by having the image sensor perform both conventional imaging and specialized PPG detection functions. The multiple pixels serve dual purposes: capturing spatial information and providing wavelength-specific photoplethysmography measurements, thereby improving dynamic range without requiring entirely separate dedicated hardware systems
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 effectively reduces noise interference and enhances detection accuracy by using a CMOS sensor array with multiple pixels to capture light intensity changes, resulting in more reliable heart rate measurements.
Implementation Method 1
an image sensor including a CMOS (complementary metal oxide silicon) sensor array to generate displacement information of light intensity gravity centers
Implementation Method 2
a PPG (photoplethysmogram) system is used to detect the heart rate according to the light brightness (light absorption) using a pulse oximeter which illuminates the skin and measures the changes in light absorption
Data Source
AI summary
This instant disclosure provides a heart rate detecting device which includes an image sensor. The image sensor generates a first mixed signal within a first interval and generates a second mixed signal within a second interval, wherein the first mixed signal contains light information of first multiple light wavelengths having a first intensity ratio from one another, and the second mixed signal contains light information of second multiple light wavelengths having a second intensity ratio, different from the first intensity ratio, from one another.