Wearable Microphone Array With Logarithmic Spiral Configuration
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Solution Overview
Problem
Existing directional microphone arrays are ineffective in noisy and reverberant environments due to wide beam widths, large side lobes, and inadequate directivity gain, leading to excessive ambient and directional noise interference, and are often uncomfortable and complex in design.
Innovation Solution
A wearable microphone array system featuring a multi-armed logarithmic spiral configuration of acoustic transducers integrated into a garment, with an audio processing module that generates an acoustic propagation model to spatially filter and extract target audio signals using a whitening filter, suppressing non-target audio signals and providing improved signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional directional microphone arrays are used, then device complexity is reduced, but beam width becomes wide and side lobes become large, causing excessive ambient and directional noise interference
Solution Approach 1:
The microphone array is segmented into multiple independent microphone elements arranged in a specific geometric pattern, allowing individual control of each element's contribution to the overall directional response. This segmentation enables precise control of beam width and side lobe levels while maintaining manageable system complexity through modular architecture.
Solution Approach 2:
Different regions of the microphone array are optimized for different functions: the central region provides main lobe directionality for the desired sound source, while the peripheral regions are configured to suppress side lobes and ambient noise. This local optimization achieves narrow beam width and low side lobe levels without requiring uniform complexity across the entire array.
2Reliability
If the number of microphones is increased to improve directivity gain, then beam width narrows and directivity improves, but device complexity and hardware requirements increase
Solution Approach 1:
Multiple microphone signals are merged through sophisticated signal processing algorithms that combine the information from individual microphones into a unified directional output. This merging process achieves high directivity gain and narrow beam width without requiring a proportional increase in physical microphone count, as the processing algorithms extract directional information efficiently from the microphone array output.
Solution Approach 2:
The patent replaces additional mechanical microphones with digital signal processing operations that achieve directional filtering through computational means. Instead of physically adding more sensing elements to increase directivity, the system uses algorithmic processing to achieve the same effect, reducing hardware complexity while maintaining or improving directivity gain.
3Object-affected harmful factors
If beam width is narrowed to reduce ambient noise, then directional selectivity improves, but the system becomes more sensitive to frequency variations and requires more complex processing
Solution Approach 1:
The signal processing system dynamically adapts its characteristics based on the acoustic environment and desired directional response. The processing algorithms adjust beam width, side lobe suppression, and frequency response in real-time to maintain optimal performance across varying conditions, reducing the need for complex fixed processing configurations while achieving narrow beam width and low off-axis capture.
Solution Approach 2:
The system changes processing parameters such as beam width, side lobe level, and frequency response characteristics to optimize directional selectivity. By dynamically adjusting these parameters rather than using fixed complex processing, the system achieves narrow beam width and reduced off-axis sound capture with manageable processing complexity that adapts to environmental conditions.
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 system achieves significant noise reduction and improved signal-to-noise ratio, providing clear and natural audio in noisy environments with a narrow beam width across the frequency range, enhancing user experience in noisy and reverberant settings.
Implementation Method 1
a plurality of acoustic transducers being housed within or coupled to an anterior portion of the garment, wherein the plurality of acoustic transducers are operably engaged to comprise an array and configured to receive an acoustic audio input
Implementation Method 2
applying a whitening filter to the target audio signal, wherein the whitening filter is configured to whiten the target audio signal and suppress non-target audio signals from the acoustic audio input
Implementation Method 3
processing the acoustic audio input according to the acoustic propagation model to spatially filter and extract a target audio signal from the acoustic audio input
Data Source
AI summary
A wearable microphone array apparatus and system used as a directional audio system and as an assisted listening device. The present invention advances hearing aids and assisted listening devices to allow construction of a highly directional audio array that is wearable, natural sounding, and convenient to direct, as well as to provide directional cues to users who have partial or total loss of hearing in one or both ears. The advantages of the invention include simultaneously providing high gain, high directivity, high side lobe attenuation, and consistent beam width; providing significant beam forming at lower frequencies where substantial noises are present, particularly in noisy, reverberant environments; and allowing construction of a cost effective body-worn or body-carried directional audio device.