Virtual Rotating Microphone for Acoustic Angle Detection
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Solution Overview
Problem
Conventional circular microphone arrays for acoustic angle of arrival detection require a large number of microphones, leading to increased material and computational costs, power consumption, and memory usage, especially in small devices like smartphones, due to the need for complex signal processing and large sample sets.
Innovation Solution
The method employs a virtual rotating microphone concept using a fixed circular microphone array to generate a synthetic audio signal through sequential sampling, leveraging sign-based frequency counting algorithms to determine the acoustic angle of arrival, reducing computational load and power consumption by eliminating the need for Fourier transforms and multiplication operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a circular array of microphones is used to detect acoustic angle of arrival, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent creates a virtual rotating microphone signal by copying and reordering samples from fixed microphones in a circular array. Instead of using a physically rotating microphone, the system copies samples from multiple fixed microphones and arranges them sequentially to simulate the time-varying signal that would be produced by a rotating microphone, thereby achieving the same measurement precision with simpler hardware
Solution Approach 2:
The patent replaces the mechanical rotation of a single microphone with a static circular array of microphones. The mechanical rotating system is substituted by an electronic signal processing system that sequentially samples fixed microphones and constructs a virtual rotating signal, eliminating mechanical complexity while maintaining measurement precision
2Measurement precision
If conventional signal processing methods are used for angle detection, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent extracts only the essential information needed for angle detection by using sign-based frequency counting instead of full Fourier transforms. The method takes out only the sign changes of the virtual rotating microphone signal and counts frequency occurrences, discarding unnecessary computational steps while retaining sufficient precision for angle estimation
Solution Approach 2:
The patent applies partial action by using a simplified frequency counting method that processes only the necessary portions of the signal. Instead of performing complete spectral analysis, the system counts frequency occurrences based on sign changes, which is a partial processing approach that consumes less power while achieving adequate measurement precision
3Measurement precision
If a large number of microphones are used in the circular array, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent makes each microphone in the circular array multi-functional by having all microphones participate in creating the virtual rotating signal. Each microphone serves multiple purposes: capturing acoustic information for its own position and contributing to the time-varying signal that enables angle detection, thereby maximizing the utility of each component and reducing the need for additional microphones
Solution Approach 2:
The patent introduces dynamic sampling where the system sequentially activates different microphones at different time intervals to create a time-varying virtual signal. This dynamic approach allows a smaller number of microphones to achieve the same measurement precision that would require more microphones in a static configuration, as each microphone contributes to multiple virtual positions over time
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 enables efficient and precise acoustic angle of arrival detection with reduced hardware requirements and power consumption, allowing for high-speed operation without mechanical noise, and is effective in various acoustic environments without additional sensors or processor hardware.
Implementation Method 1
determine a virtual signal that imitates an audio signal of a moving or rotating microphone based on the sequential sampling of the circular array
Data Source
AI summary
An audio processing device and method uses audio signals from a virtual rotating microphone for acoustic angle of arrival detection using a doppler effect technique.