MIMO Acoustic Localization Using Tone Signals and DAS
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Solution Overview
Problem
Conventional indoor sound localization techniques are unable to detect silent objects and perform poorly when localizing objects emitting continuous single tones due to reflections and diffusions.
Innovation Solution
A MIMO method using multiple speakers to generate tone signals at different frequencies and multiple acoustic sensors to demodulate the complex amplitude, allowing for the detection and localization of silent objects by monitoring the feature variation of the relative phase or intensity vector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sound localization techniques are used, then objects emitting sound can be localized, but silent objects cannot be detected and performance deteriorates for continuous single tone sources due to reflections and diffusions
Solution Approach 1:
Instead of requiring the object to emit sound for detection, the system inverts the approach by using active acoustic sources (speakers) to transmit sound waves that interact with the object. The reflected waves carry information about the object's position and presence, enabling detection of silent objects through the acoustic field interactions rather than relying on the object's own sound emission.
Solution Approach 2:
The system introduces acoustic waves as an intermediary carrier that interacts with the silent object. The sound waves serve as a mediator between the detection system and the object, carrying information about the object's position and characteristics through reflections and interactions with the acoustic field, thereby enabling indirect detection without the object needing to emit sound.
2Measurement precision
If multiple speakers generate tone signals at different frequencies with multiple acoustic sensors for MIMO detection, then silent objects can be detected and localized, but device complexity increases
Solution Approach 1:
The system segments the acoustic detection task by using multiple speakers emitting different frequency tones and multiple sensors to capture the acoustic field. Each speaker-sensor pair contributes specific information about the acoustic interactions, and the combined data from all segments enables precise localization through MIMO processing, dividing the complex detection task into manageable components.
Solution Approach 2:
The system changes the acoustic parameters by using multiple frequency tones simultaneously from different speakers. This parameter variation creates distinct acoustic interaction patterns with the object that can be differentiated and processed to improve localization accuracy, utilizing frequency diversity to enhance the measurement capability beyond what a single frequency could provide.
3Device complexity
If fiber-optic distributed acoustic sensing is used, then cost and complexity are reduced while maintaining detection capability, but requires optical fiber infrastructure
Solution Approach 1:
The system replaces traditional electrical sensor networks with an optical fiber-based distributed acoustic sensing system. The optical fiber serves as the sensing medium, using light-based detection mechanisms instead of electrical signals, thereby reducing electromagnetic interference and enabling passive detection that preserves privacy by not requiring active electronic sensors at each measurement point.
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 the detection and localization of silent objects without requiring them to emit sound, improving performance over conventional methods and reducing cost and complexity through the use of a fiber-optic system with distributed acoustic sensing.
Implementation Method 1
multiple speakers generate tone signals at different frequencies
Implementation Method 2
multiple acoustic sensors demodulate the complex amplitude of each frequency
Implementation Method 3
a fiber-optic system and method that employs distributed acoustic sensing (DAS)
Data Source
AI summary
Disclosed are systems and methods directed to a MIMO method that detects and localizes an object without requiring the object to emit a sound. Operationally, multiple speakers generate tone signals at different frequencies, while multiple acoustic sensors demodulate the complex amplitude of each frequency. By monitoring the feature variation of the relative phase (or intensity) vector from the complex amplitude, our method detects or localizes movement of the object. For large-scale applications, a fiber-optic system and method that employs distributed acoustic sensing (DAS) in which an optical fiber is used as one or more acoustic sensors located at points along the length of the optical fiber. A single DAS system provides numerous sensors using only a single optical fiber thereby enabling perfect synchronization and centralized signal processing. Notably, with such a DAS arrangement, cost and complexity is significantly reduced, while privacy is preserved.