Wavelength-Segmented Measuring Instrument for Contactless Heartbeat Detection
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Solution Overview
Problem
Existing biological information measuring instruments face challenges in separating heartbeat components from illumination variables due to low sensitivity of second pixels, leading to noise interference in time-series data.
Innovation Solution
A measuring instrument with a camera that includes groups of pixels with specific peak sensitivity wavelengths and larger light-receiving areas, particularly for red pixels, to enhance signal-to-noise ratio and reduce noise influence, allowing precise separation of heartbeat and illumination components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If second pixels are designed to receive light in narrow wavelength ranges outside heartbeat sensitivity region, then illumination variable component can be separated from heartbeat component, but sensitivity of second pixels becomes low causing high noise in time-series data
Solution Approach 1:
The patent changes the wavelength range parameter for second pixels from narrow ranges (500-530nm, 590-620nm) to broader ranges including 450-500nm, 530-590nm, and 620-750nm. This parameter change increases light reception quantity while maintaining the ability to separate illumination components, thereby improving signal-to-noise ratio without sacrificing separation precision.
2Measurement precision
If total light-receiving area of first pixels is increased to improve signal quantity, then measurement precision of heartbeat component improves, but device structure becomes more complex
Solution Approach 1:
The imaging element is segmented into distinct groups: first pixels for heartbeat detection (620-750nm), second pixels for illumination detection (broader wavelengths), and optionally third pixels for additional wavelengths. This segmentation allows each pixel group to be optimized for its specific function while maintaining overall system manageability and reducing structural complexity compared to a uniform high-density pixel array.
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 accurate measurement of biological information, such as heart rate, blood pressure, and oxygen saturation, by minimizing noise and body movement artifacts, thereby improving precision in contactless volume pulse wave detection.
Implementation Method 1
a camera 101 that captures an image of a living body LB at a distance from the living body LB
Implementation Method 2
an imaging element 112 including: a group of first pixels 121R that exhibit a peak sensitivity wavelength of greater than or equal to 620 nm and less than or equal to 740 nm; and a group of second pixels 121G, 121B, 121IR exhibiting a peak sensitivity wavelength of either less than or equal to 600 nm or greater than or equal to 760 nm
Data Source
AI summary
A measuring instrument including: a camera that captures an image of a living body at a distance from the living body, the camera including an imaging element including: a group of first pixels that exhibit a peak sensitivity wavelength of greater than or equal to 620 nm and less than or equal to 740 nm; and a group of second pixels including a group of pixels of at least one color, the second pixels exhibiting a peak sensitivity wavelength of either less than or equal to 600 nm or greater than or equal to 760 nm, the group of first pixels having a total light-receiving area that is larger than a total light-receiving area of a group of pixels of each color; and a processing unit that processes a signal representing quantities of light received by the group of first pixels and the group of second pixels.