Hearing Instrument Adaptive Null Direction Control
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Solution Overview
Problem
Existing directional signal processing systems in hearing instruments struggle to effectively suppress sound sources from all directions, particularly in environments with multiple desired sound sources, leading to potential suppression of desired sounds.
Innovation Solution
A hearing instrument with at least two microphones and a signal processor that generates a combined signal with an adaptive null direction, preventing this null direction from entering prohibited ranges based on parameters like sound power or signal-to-noise ratio, ensuring suppression of undesired sounds while preserving desired sounds from specific directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If directional signal processing is used to suppress sound sources, then noise reduction is improved, but desired sound sources may be suppressed
Solution Approach 1:
The patent implements dynamic adjustment of the directivity pattern by making the null direction adaptive rather than fixed. The system continuously monitors acoustic parameters and adjusts the null direction in real-time to track and avoid desired sound sources while maintaining suppression of noise sources, resolving the contradiction between noise reduction and desired sound preservation
Solution Approach 2:
The system employs feedback mechanisms by monitoring acoustic parameters (such as signal-to-noise ratio, inter-microphone level difference, and zero-crossing rate) and using this information to dynamically adjust the directivity pattern. This feedback loop ensures that the null direction adapts to changing acoustic environments and avoids suppressing desired sound sources
2Object-affected harmful factors
If fixed null direction is used, then suppression of sound from specific direction is improved, but adaptability to changing environments deteriorates
Solution Approach 1:
The patent transforms the fixed null direction into a dynamic, adaptive parameter that changes in response to environmental conditions. The system calculates acoustic parameters continuously and updates the directivity pattern accordingly, enabling the null direction to adapt to changing noise sources and acoustic environments while maintaining effective sound suppression
3Object-affected harmful factors
If adaptive directivity pattern is used, then capability to suppress sound from all directions is improved, but risk of suppressing desired sounds increases
Solution Approach 1:
The patent applies local quality by creating different processing characteristics for different spatial directions. The system maintains strong suppression (null direction) for noise sources while preserving sensitivity in directions where desired sound sources are located, achieving localized optimization of sound suppression without compromising desired sounds
Solution Approach 2:
The system dynamically adjusts the directivity pattern based on real-time acoustic parameter analysis, making the suppression capability adaptive rather than uniform across all directions. This allows the system to suppress sounds from all directions when appropriate while avoiding suppression of desired sounds through continuous parameter monitoring and adjustment
Data Source
AI summary
A hearing instrument includes a signal processor, and at least two microphones for reception of sound and conversion of the received sound into corresponding electrical sound signals that are input to the signal processor, wherein the signal processor is configured to process the electrical sound signals into a combined signal with a directivity pattern with at least one adaptive null direction θ, and wherein the signal processor is further configured to prevent the at least one null direction θ from entering a prohibited range of directions, wherein the prohibited range is a function of a parameter of the electrical sound signals.