Electronic Device Using Range-Velocity FFT for Heartbeat Detection
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Solution Overview
Problem
Existing technologies struggle to accurately detect weak oscillations such as heartbeats in human bodies using radio waves, particularly in various environments and applications.
Innovation Solution
An electronic device equipped with a transmission and reception antenna system, capable of transmitting and receiving radio waves, performs fast Fourier transforms to extract heartbeat oscillations, allowing for accurate detection and calculation of heart rates through oscillation component removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If radio waves are transmitted to detect heartbeat oscillations, then non-contact monitoring is achieved, but detection precision deteriorates due to weak signal strength
Solution Approach 1:
The patent transforms the 1D heartbeat detection problem into a 2D analysis by performing fast Fourier transform in both range direction and velocity direction. This creates a two-dimensional frequency spectrum where heartbeat oscillations can be distinguished from other movements based on their unique position characteristics in the range-velocity plane, thereby improving detection precision while maintaining non-contact monitoring
Solution Approach 2:
The patent extracts only the oscillation components lying at desired positions from the two-dimensional frequency spectrum obtained through fast Fourier transform. By removing oscillation components at other positions, the system isolates the heartbeat signal from background noise and other movements, significantly improving heartbeat detection precision while maintaining non-contact operation
2Measurement precision
If fast Fourier transform is performed in range and velocity directions, then heartbeat oscillations are extracted, but calculation complexity increases
Solution Approach 1:
The patent segments the signal processing into distinct stages: first performing fast Fourier transform in the range direction to obtain range information, then performing fast Fourier transform in the velocity direction on the extracted range components. This segmentation allows the complex two-dimensional transformation to be broken down into manageable sequential steps, reducing computational complexity while maintaining the ability to accurately extract heartbeat oscillations
3Measurement precision
If oscillation components are removed except for desired positions, then heartbeat signal is enhanced, but information loss occurs
Solution Approach 1:
The patent uses the two-dimensional frequency spectrum obtained through fast Fourier transform as an intermediary representation. In this spectral domain, heartbeat oscillations appear at specific desired positions that are distinct from other movements. By working in this intermediate spectral representation rather than directly in the time domain, the system can selectively enhance heartbeat signals while minimizing information loss, as the spectral transformation preserves all original signal information in a different representation
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 precise detection and monitoring of heartbeats in humans and animals, facilitating health condition management in diverse settings including indoor and outdoor environments.
Implementation Method 1
a reception antenna, and a signal processor. The transmission antenna transmits a transmission wave. The reception antenna receives a reflected wave, the reflected wave being the transmission wave having been reflected
Data Source
AI summary
An electronic device includes a transmission antenna, a reception antenna, and a signal processor. The transmission antenna transmits a transmission wave. The reception antenna receives a reflected wave that is the transmission wave having been reflected. Based on a transmission signal transmitted as the transmission wave and a reception signal received as the reflected wave, the signal processor detects oscillations arising from a heartbeat of a subject that reflects the transmission wave. Based on oscillation velocity obtained through oscillation component removal except for an oscillation component lying at a desired position from a result of performing a fast Fourier transform in a range direction and a velocity direction on the reception signal, the signal processor calculates the heartbeat of the subject.