Clip-On Microphone Assembly With Orientation-Steered Beamforming
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Solution Overview
Problem
Hearing impaired individuals face challenges in speech understanding in noisy and reverberant environments due to inadequate signal-to-noise ratio, and existing wireless microphones are cumbersome and difficult to place correctly.
Innovation Solution
A clip-on microphone assembly with a beamformer unit, controlled by a voice activity detector, direction of arrival unit, and acceleration sensor, automatically adjusts the acoustic beam's direction and width to optimize signal-to-noise ratio by determining the allowed angular sector and steering the beam towards the user's mouth, regardless of placement or orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a boom microphone is used to achieve best speech pickup performance, then signal-to-noise ratio is improved, but device complexity and ease of operation deteriorate due to complex fixation requirements and difficult placement
Solution Approach 1:
The system divides the microphone assembly into separate functional components: a clip-on body wearing unit with microphones and an audio signal processing unit with beam forming capability. This segmentation allows the microphones to be positioned optimally on the body while the complex signal processing occurs separately, simplifying the physical placement requirements.
Solution Approach 2:
The patent replaces the mechanical positioning requirement of boom microphones with an electronic/software-based beam forming system. Instead of requiring precise mechanical placement close to the mouth, the system uses digital signal processing to create directional acoustic beams that electronically steer the pickup pattern towards the speaker's mouth based on orientation detection.
2Reliability
If a directional microphone assembly is placed close to the mouth for optimal performance, then signal-to-noise ratio is improved, but ease of operation worsens due to difficulty in correct placement and orientation
Solution Approach 1:
The system incorporates orientation detection capabilities that provide feedback about the microphone assembly's spatial orientation. This feedback is used by the beam forming algorithm to adjust the acoustic beam direction dynamically, allowing the system to maintain optimal performance regardless of how the user positions or orients the clip-on device on their clothing.
Solution Approach 2:
The beam forming system automatically adjusts and optimizes the acoustic beam direction based on detected orientation and sound source location without requiring user intervention. The system self-corrects for improper placement or orientation, eliminating the need for users to precisely position the microphone assembly.
3Ease of operation
If a beam former unit is added to automatically adjust acoustic beam direction, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The audio signal processing unit performs multiple functions: it captures audio signals from multiple microphones, detects orientation using acceleration sensors, determines direction of arrival of sound sources, and executes beam forming algorithms. By consolidating these diverse functions into a single integrated processing unit, the system manages complexity while providing automatic beam adjustment capabilities.
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 solution provides a convenient and effective way to improve the signal-to-noise ratio of the output audio signal, allowing for simple attachment and optimal speech pickup, even in varying environments, suitable for use with hearing aids and other hearing stimulation devices.
Implementation Method 1
an acceleration sensor for determining an orientation of the microphone assembly
Implementation Method 2
a beam former unit for processing the captured audio signals in a manner so as to create an acoustic beam
Data Source
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Figure 5~6
AI summary
There is provided a clip-on microphone assembly comprising a clip-on mechanism (16) for attaching the microphone assembly (10) to the cloths of a user (11); at least three microphones (20, 21, 22) for capturing audio signals from the user's voice, the microphones defining a microphone plane; an acceleration sensor (32) for generating an orientation signal by sensing gravitational acceleration in at least two orthogonal dimensions, an audio signal processing unit (34) for producing an output audio signal (36) from the captured audio signals, comprising a beamformer unit (24) for processing the captured audio signals, in order to generate the output audio signal, in a manner so as to create an acoustic beam having a direction, a DOA unit (30) for determining the direction of arrival of sound by analyzing the captured audio signals; and a control unit (26) for controlling the beamforming unit, the control unit being adapted to determine an allowed angular sector (40) of the direction of the acoustic beam according to the orientation signal and to steer the direction of the acoustic beam within the allowed angular sector according to the determined direction of arrival.