FMCW Audio Hand Tracking for Device-Free Control
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Solution Overview
Problem
Current user interfaces for smart devices, VR, and AR are cumbersome, relying on tapping, swiping, or voice recognition, lacking an easy and intuitive method for users to interact and control these devices.
Innovation Solution
A device-free motion tracking system using Frequency Modulated Continuous Wave (FMCW) radar that transmits and receives audio signals to estimate the distance and velocity of a moving hand, allowing for accurate tracking and control of devices using widely available speakers and microphones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional user interfaces (tapping, swiping, voice recognition) are used to control smart devices, then device control functionality is achieved, but user convenience and ease of operation deteriorate
Solution Approach 1:
The patent replaces traditional mechanical interaction methods (tapping, swiping) with acoustic wave-based detection. Speakers emit acoustic waves that reflect off the user's hand, and microphones capture these reflections to track hand position and gestures, eliminating the need for physical contact with the device interface.
Solution Approach 2:
The patent introduces acoustic waves as an intermediary between the user and the device. Instead of direct mechanical interaction or voice commands, the user's hand movements modulate acoustic waves emitted by speakers, and these modulated waves are detected by microphones to control the device, providing a natural and intuitive interaction method.
2Measurement precision
If camera-based hand tracking is used in VR/AR, then hand position can be detected, but system complexity increases and line-of-sight requirements limit usability
Solution Approach 1:
The patent replaces complex optical camera systems with a simpler acoustic wave-based detection system. Speakers emit acoustic waves that reflect off the user's hand, and microphones capture these reflections. The system processes the acoustic signals to determine hand position and gestures, achieving accurate tracking without requiring cameras or line-of-sight.
Solution Approach 2:
The patent creates an acoustic copy of the hand's position and movement by emitting acoustic waves that reflect off the hand and capturing these reflections. This acoustic copying method provides a simplified alternative to direct optical imaging, reducing system complexity while maintaining tracking accuracy.
3Ease of operation
If acoustic signals are transmitted and received for hand tracking, then device-free control is achieved, but signal processing complexity increases
Solution Approach 1:
The patent uses the device's existing speakers and microphones for hand tracking, making the system self-sufficient. The speakers emit acoustic waves and the microphones capture reflections, eliminating the need for external sensors or cameras. This self-service approach enables device-free control while minimizing additional hardware 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
Enables users to interact and control devices by simply moving their hands, providing a more intuitive and efficient interface for smart devices, VR, and AR, enhancing user experience and interaction capabilities.
Implementation Method 1
receiving samples of the audio signals reflected from the object
Implementation Method 2
estimating a velocity of the object... estimating a distance from a speaker of the controlled device to a microphone of the controlled device via the object based on the selected one or more peak frequencies and velocity of the object
Data Source
AI summary
A method, system and computer program product for tracking movement of an object, such as a hand. Speakers of a device to be controlled transmit frequency modulated continuous wave (FMCW) audio signals. These signals are reflected by the object and received by the microphones at the controlled device. The received and transmitted audio signals are mixed. A fast Fourier transform (FFT) is then performed on the mixed audio signals. One or more peak frequencies in the frequency domain of the FFT mixed audio signals are selected and used to estimate the distance between the object and the speakers of the controlled device. Furthermore, the velocity of the object is estimated. The coordinates of the object are then computed using the estimated distance between the object and the speakers and microphones of the controlled device and the estimated velocity of the object.