Wireless Hearing Assistance Gain Control for Quiet Speech
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Solution Overview
Problem
Current wireless hearing assistance systems face challenges in maintaining optimal signal-to-noise ratios, especially in quiet conditions where soft voices or distant speakers result in uneven sound levels due to a fixed gain model that does not adapt to varying ambient noise levels.
Innovation Solution
A dynamic gain model is introduced where the kneepoint, which marks the transition from a linear to a compressive gain range, adjusts based on ambient noise levels, allowing for increased gain at lower speech levels and reducing the impact of microphone distance variations, thereby stabilizing sound levels and increasing the acceptable distance between the speaker and microphone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed gain model is used in wireless hearing assistance systems, then the system is simple to operate, but the sound levels become uneven in quiet conditions where soft voices or distant speakers are present
Solution Approach 1:
The patent applies dynamics by making the gain model adaptive rather than fixed. The system continuously adjusts the gain based on real-time analysis of the auditory scene, detecting whether the environment is noisy or quiet and whether speech is present. This dynamic adaptation allows the gain to vary automatically with changing conditions, resolving the contradiction between operational simplicity and sound level stability.
Solution Approach 2:
The patent changes the parameter of gain based on detected auditory scene characteristics. By monitoring ambient noise levels and speech presence, the system modifies the gain parameter dynamically - applying higher gain in quiet conditions with soft voices and lower gain in noisy environments. This parameter change strategy maintains sound level stability across varying operational conditions while keeping the user interface simple.
2Adaptability or versatility
If the microphone is placed farther from the speaker, then the system is more versatile, but the signal-to-noise ratio deteriorates
Solution Approach 1:
The patent implements feedback by continuously analyzing the captured audio signal to detect speech presence and ambient noise levels. This feedback information is used to automatically adjust the gain parameter, compensating for the reduced signal level that occurs when the microphone is placed farther from the speaker. The system monitors the auditory scene and adapts the gain in real-time, maintaining acceptable signal-to-noise ratios even with increased microphone-speaker distance.
Solution Approach 2:
The system dynamically adjusts the gain based on the actual distance and acoustic conditions. When the microphone is placed farther from the speaker, the system detects the lower speech level and increases the gain accordingly. This dynamic compensation allows versatile microphone placement while maintaining reliable signal-to-noise ratios through automatic adaptation to the acoustic environment.
3Reliability
If the gain is increased to compensate for distant speakers or soft voices, then the signal level improves, but the background noise level also increases
Solution Approach 1:
The patent applies parameter changes by selectively adjusting the gain based on the detected auditory scene. The system analyzes whether speech is present and what the ambient noise level is, then modifies the gain parameter accordingly. In quiet conditions with soft voices, the system applies higher gain to improve signal level. In noisy environments, the system maintains lower gain to prevent excessive noise amplification. This conditional parameter adjustment resolves the contradiction between improving signal level and controlling background noise.
Solution Approach 2:
The patent applies local quality by treating different auditory conditions differently through selective gain application. Rather than applying a uniform gain setting, the system analyzes the local acoustic characteristics - detecting speech presence, speaker distance, and ambient noise levels - and adjusts the gain locally based on these conditions. This allows the system to improve signal level when needed while avoiding noise amplification in inappropriate conditions.
Data Source
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AI summary
The invention relates to a method for providing hearing assistance to a user, comprising: capturing input audio signals by a microphone arrangement (42); estimating a speech level of the input audio signals and an ambient noise level of the input audio signals; applying a gain model to the input audio signals in order to transform the input audio signals into filtered audio signals, wherein, for a each ambient noise level, the gain varies as a function of the speech level and wherein the function varies according the ambient noise level in such a manner that the ratio of the gain at low speech levels and at high speech levels changes as a function of the ambient noise level; transmitting the filtered audio signals by a transmission unit (10) via a wireless audio link (34) to a receiver unit (14, 36, 38) comprising or being connected to means (18, 26) for stimulating the hearing of a user, the stimulating means being worn at or in the user's ear; and stimulating the user's hearing by the stimulating means according to the audio signals supplied by the receiver unit.