Movable Microphone Array for Sound Source Localization
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Solution Overview
Problem
Conventional microphone array beamforming methods require a large number of sensors for accurate sound source localization, which is costly and limits the practical application due to the high price of measuring sensors and data acquisition devices.
Innovation Solution
A movable microphone array system where a fixed sensor is used in conjunction with movable sensors that measure sound at multiple points, with a signal processing method to synchronize the data from the movable sensors with the fixed sensor, allowing for improved measurement accuracy with a reduced number of sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of sensors is increased to improve measurement accuracy, then measurement precision is improved, but device cost and complexity increase
Solution Approach 1:
The patent applies the dynamics principle by making the microphone array movable rather than static. The array can be positioned at multiple locations around the sound source, transforming a static measurement system into a dynamic one that collects data from multiple spatial positions. This allows a smaller number of microphones to gather equivalent information that would otherwise require many more fixed sensors distributed throughout the measurement space.
Solution Approach 2:
The patent adds the temporal dimension to the measurement process by collecting data sequentially at different time points as the array moves to different positions. Instead of requiring all sensors to be present simultaneously in space, the system achieves comprehensive spatial coverage by moving a smaller array through multiple positions over time, then synthesizing the results through signal processing.
2Measurement precision
If the number of sensors is increased to improve side-lobe rejection, then measurement precision is improved, but device cost increases
Solution Approach 1:
By making the microphone array movable and collecting measurements at multiple positions, the system dynamically enhances its ability to reject side lobes. The signal processing method combines measurements from different positions to achieve side-lobe rejection performance equivalent to that of a much larger fixed array, without requiring the corresponding increase in sensor quantity.
Solution Approach 2:
The patent performs preliminary measurements at multiple predetermined positions before synthesizing the final result. By collecting data from multiple locations in advance and then processing this data together, the system achieves enhanced side-lobe rejection that would require many more sensors if measured in a single static position.
3Measurement precision
If a large number of sensors are used to reduce beam width, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The movable array configuration allows the system to achieve narrow beam width performance by collecting measurements from multiple positions. The dynamic movement of the array through different locations enables the synthesis of a focused beam pattern that would require many more fixed sensors to achieve in a static configuration.
Solution Approach 2:
The patent transitions from a single spatial plane measurement to a multi-position measurement approach, adding the dimension of movement along a predetermined path. This allows the system to achieve narrow beam width characteristics by combining measurements taken at different positions along the movement path, effectively synthesizing the performance of a much larger sensor 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
The method achieves measurement accuracy comparable to using multiple sensors while significantly reducing the number of sensors required, thereby lowering costs and improving performance, with enhanced side-lobe rejection and beam width characteristics.
Implementation Method 1
Sound waves u(t) generated from a sound source are measured using a plurality of microphones
Data Source
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AI summary
Disclosed is an enhanced sound source localization technique, which can overcome a limitation of a conventional beamformmg method using a fixed microphone array by applying a movable microphone array and an analytic algorithm related to the movable microphone array. An object of the present invention is to provide an enhanced sound source localization system and method by using a movable microphone array, wherein a sound source is measured by moving a limited number of microphones, and a signal processing method capable of synchronizing the microphones, so that measurement accuracy can be improved. According to the present invention, a sound source is measured by moving a limited number of microphones, the number of sensors required to evaluate measured values in a range of desired measurement accuracy can be considerably decreased, and therefore, measuring cost can be remarkably saved.