Omni-directional Microphone Array for Noise Suppression
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Solution Overview
Problem
Existing array microphone techniques, such as broadside beam forming, require complex algorithms and significant computational resources, making them costly and inflexible for noise suppression in communication and voice recognition systems, especially when dealing with varying frequencies and environments.
Innovation Solution
An apparatus comprising three omni-directional microphones arranged in a horizontal coplanar alignment, with a directional microphone forming device and a magnitude and phase response handler, generates a bi-directional beam forming signal that reduces noise from specific directions without requiring complex algorithms or additional memory, functioning across all bandwidths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If broadside beam forming technique is used to achieve noise suppression and speech enhancement, then noise suppression performance is improved, but device complexity and computational resource requirements increase significantly
Solution Approach 1:
The patent segments the beam forming process into two independent channels: a first channel for processing signals from the first microphone and a second channel for processing signals from the second microphone. Each channel operates with simplified processing rather than complex joint processing, reducing overall system complexity while maintaining noise suppression capability.
Solution Approach 2:
The patent replaces complex digital signal processing algorithms (FFT, adaptive suppression, inverse FFT) with a simpler analog-like signal combining approach using delay elements and adders. This substitution of complex computational mechanisms with simpler signal processing blocks reduces device complexity and computational resource requirements.
2Reliability
If broadside beam forming with FFT and adaptive suppression algorithms is implemented, then noise suppression capability is improved, but computational power and memory requirements increase
Solution Approach 1:
The patent extracts and eliminates the need for complex algorithms such as FFT, adaptive suppression, and inverse FFT from the system. By removing these computationally intensive components and replacing them with simpler delay and addition operations, the system achieves noise suppression with significantly reduced computational power and memory requirements.
3Device complexity
If end fire beam forming technique is used to simplify the array configuration, then device complexity is reduced, but applicability is limited due to inability to suppress front signal sources
Solution Approach 1:
The patent creates a universal beam forming solution that can suppress noise from multiple directions (front and sides) simultaneously while maintaining the simplicity of the end-fire configuration. The system achieves multi-directional noise suppression capability without requiring complex broadside array geometries, thus maintaining simplicity while expanding applicability to various scenarios including front-facing signal sources.
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 effectively suppresses noise from unwanted directions while maintaining sound from desired directions, converting an omni-directional array into a bidirectional pattern, and operates efficiently across all frequencies without the need for complex algorithms or high computational power.
Implementation Method 1
at least a first, a second and a third omni-directional microphone, m1, m2 and m3, respectively
Implementation Method 2
a directional microphone forming device 2, a magnitude and phase response handler device 3, and a combining device 4
Data Source
AI summary
Embodiments described in the present disclosure relate to an array microphone apparatus for generating a beam forming signal. The apparatus includes first, second, and third omni-directional microphones, each converting an audible signal into a corresponding electrical signal. The three microphones are arranged in a horizontal coplanar alignment, and the second microphone is disposed between the other two microphones. The apparatus includes a first directional microphone forming device to jointly output a first directional microphone signal with a first bi-directional pattern, and a magnitude and phase response handler device to output a second directional microphone signal with an omni-directional pattern shifted by a prefixed value with respect to first directional microphone signal. The apparatus further includes a combining device receiving the first and second directional microphone signals and outputting a combined directional microphone signal with a combined beam pattern correlated to the first bi-directional and second omni-directional patterns, the combined directional microphone signal being perpendicular to the horizontal coplanar alignment of the first, second, and third omn-directional microphones.