Hearing Aid Transient Detection for Click-Free Noise Attenuation

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Solution Overview

Problem

Modern hearing aids struggle to effectively attenuate sharp transient noises while maintaining clear speech reproduction, as existing compression methods are complex, power-intensive, and often introduce clicks or artefacts, failing to differentiate between speech and non-speech transients efficiently.

Innovation Solution

A hearing aid with a transient detection system that splits input signals into frequency bands, using a 90% percentile estimator and threshold comparators to dynamically control gain, distinguishing between speech and non-speech transients by detecting slopes exceeding 5 dB/sample, and applying appropriate compression to attenuate only non-speech transients, thus reducing power consumption and improving sound quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional compression methods are used to attenuate transient noises, then the output signal level is reduced below the upper comfort level, but the method introduces clicks or artefacts and fails to differentiate between speech and non-speech transients

Engineering Contradiction:

Improvetransient noise attenuationVSAvoidclicks and artefacts

Core Design Contradiction:

Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent applies different compression characteristics to different parts of the signal by detecting transient characteristics (slope exceeding threshold, zero-crossing behavior) and applying specific attenuation only to identified non-speech transients, while leaving speech signals unaffected. This localized approach prevents artefacts while achieving noise attenuation.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of compressing all transients uniformly, the patent inverts the approach by detecting and identifying non-speech transients through their characteristic features (steep slope, zero-crossing patterns) and applying compression selectively, thereby preserving speech quality while attenuating harmful noises.

Inventive Principle:

Principle #13The other way round (Inversion)

2Speed

If the compressor reacts quickly to attenuate transients, then transient noises are effectively reduced, but repeated transients reduce the amplification considerably for several seconds after the transient sounds are over

Engineering Contradiction:

Improvecompressor reaction speedVSAvoidamplification recovery time

Core Design Contradiction:

SpeedVSDuration of action of moving object

Solution Approach 1:

The patent implements dynamic control of the compressor by adjusting the attack and release times based on the detected transient characteristics. For identified non-speech transients, the system applies fast attack to quickly attenuate the noise, followed by adaptive release timing that prevents excessive gain reduction duration, thereby maintaining natural sound reproduction while protecting against repeated transient damage.

Inventive Principle:

Principle #15Dynamics

3Object-affected harmful factors

If the gain is reduced quickly to attenuate transients, then transient noises are effectively suppressed, but soft sounds immediately following loud sounds receive too little gain

Engineering Contradiction:

Improvetransient noise suppressionVSAvoidgain accuracy for soft sounds

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies different gain control strategies to different signal components by identifying transients through their characteristic features and applying targeted attenuation only to those components, while maintaining normal gain control for subsequent soft sounds. This selective approach ensures transient suppression without compromising the accuracy of soft sound reproduction.

Inventive Principle:

Principle #3Local quality

4Manufacturing precision

If complex compression algorithms are used to differentiate speech from non-speech, then speech quality is maintained, but power consumption increases

Engineering Contradiction:

Improvespeech reproduction qualityVSAvoidpower consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the detection parameters to focus on key transient characteristics (slope threshold, zero-crossing behavior) that effectively differentiate speech from non-speech transients. By monitoring these specific parameters rather than implementing full-spectrum analysis, the system achieves reliable speech/non-speech differentiation with reduced computational complexity and lower power consumption.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8929574B2Hearing aid and a method of detecting and attenuating transients

Publication Date: 2015.01.06 WIDEX AS

AI summary

A hearing aid has means (15) for detecting fast transients in the input signal and means (16, 12, 13) for attenuating the detected transients prior to presenting the signal with the attenuated transients to a user. Detection is performed by measuring the peak difference of the signal upstream of a band split filter bank (11) and comparing the peak difference against at least one peak difference limit. Then, if a transient is detected, a state machine (20) analyzes the peak level and the absolute average level of the signal and engages a gain calculator (12) to follow either the peak level or the absolute average level of the input signal for at least the duration of the transient in order to attenuate the transient. The engagement of the gain calculator (12) is performed in each frequency band dependent of the detected transient. The invention further provides a method for detecting fast transients.