Vital Sign Detection Using Switchable Beam Directivity
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Solution Overview
Problem
Conventional vital sign detection devices face challenges in accurately extracting vital signs due to noise from body movement and limited design flexibility in vehicles, as they require multiple sensors and occupy significant space.
Innovation Solution
A vital sign detection device with a single irradiation unit that changes directivity to scan and emit electromagnetic waves, using the difference in distance information from waves with highest signal intensity to accurately extract vital signs, even if the subject's size and orientation change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are used to accurately extract vital signs by subtracting noise elements, then measurement precision is improved, but device complexity and space occupation increase
Solution Approach 1:
The patent segments the measurement process into two distinct electromagnetic wave applications: one targeting the measurement part where vital signs strongly appear, and another targeting a reference part where only noise elements appear. This segmentation allows the system to separately acquire signal components containing only noise and signal-plus-noise, enabling accurate vital sign extraction through subtraction while using a single sensor.
Solution Approach 2:
The patent introduces an intermediary measurement part (reference part) that serves as a mediator to capture pure noise elements. By applying electromagnetic waves to this intermediate reference region, the system obtains a noise-only signal that can be subtracted from the signal-plus-noise obtained at the measurement part, thereby isolating the vital signs without requiring multiple sensors simultaneously observing the same target.
2Measurement precision
If two sensors are disposed next to each other to detect biological information and noise elements, then measurement precision is improved, but the area occupied in the seat increases
Solution Approach 1:
The patent segments the electromagnetic wave application into two sequential or alternating phases using a single sensor: one phase targets the measurement part for acquiring vital signs plus noise, and the other phase targets the reference part for acquiring pure noise. This temporal or phased segmentation replaces the spatial segmentation required by dual sensors, thereby reducing the installation area in the seat while maintaining measurement precision.
Solution Approach 2:
The single electromagnetic wave transmitting and receiving unit performs multiple functions: it acts as both the measurement sensor (when directed at the measurement part) and the reference sensor (when directed at the reference part). This multi-functionality eliminates the need for dedicated separate sensors, reducing the overall area required for sensor installation in the seat.
3Device complexity
If a single irradiation unit changes directivity to scan electromagnetic waves, then device complexity is reduced, but the time required to capture vital signs may increase
Solution Approach 1:
The patent employs periodic action by alternately or sequentially directing the single electromagnetic wave transmitting unit between the measurement part and the reference part. This periodic switching of beam direction allows the system to capture both signal-plus-noise and noise-only components in a time-multiplexed manner, maintaining detection speed while using a single irradiation unit that changes directivity.
Solution Approach 2:
The system performs preliminary action by pre-establishing the reference part as a dedicated noise capture region and pre-programming the directivity switching patterns. This allows the single irradiation unit to efficiently alternate between measurement and reference observations without real-time decision delays, minimizing the time loss associated with scanning while maintaining the simplicity of a single unit architecture.
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
This approach allows for accurate extraction of vital signs while reducing device size, increasing design flexibility, and lowering costs by using a single irradiation unit and eliminating the need for multiple sensors.
Implementation Method 1
a transmitter configured to emit electromagnetic waves toward a subject; a receiver configured to receive a plurality of returned electromagnetic waves with different directivities after having reflected off the subject
Implementation Method 2
a scan controller configured to change a directivity of transmissions from the transmitter so as to scan an irradiation region of the subject with the electromagnetic waves
Data Source
AI summary
A vital sign detection device controls directivities of radio waves A and B toward an irradiation region of a subject to determine the vital signs of the subject. The first directivity is where the vital signs easily appear and the second directivity is where the vital signs are less likely to appear. Noise is reduced by taking a difference between information about a distance to the subject calculated on the basis of the radio wave A having the first directivity and information about a distance to the subject calculated on the basis of the radio wave B having the second directivity received by the receiver.