Shock Noise Suppression via Signal Intensity Change Detection

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Solution Overview

Problem

Conventional noise suppression methods are unable to effectively suppress shock noise, such as key typing noise, without using shock noise occurrence information, and require precise detection using press-down and release information, which limits their effectiveness.

Innovation Solution

A noise suppression method that converts an input signal into a frequency region signal, detects shock noise based on changes in the signal, and suppresses it without requiring shock noise occurrence information, using a shock noise detection unit and a shock noise suppression unit to generate an emphasized sound with high quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional noise suppression methods using averaging operations are employed, then general noise suppression is achieved, but shock noise such as key typing noise cannot be detected or suppressed

Engineering Contradiction:

Improveshock noise suppression capabilityVSAvoiddetection system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the detection parameter from using press-down and release information (conventional method) to using signal intensity change rate and frequency spectrum characteristics. This allows shock noise to be detected through its distinctive rapid intensity changes and broadband spectral content, enabling effective suppression without requiring complex key state tracking systems

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the mechanical detection approach (using key press-down and release information) with a signal processing approach that analyzes the acoustic characteristics of the noise itself. By substituting the detection mechanism from mechanical state sensing to acoustic signal analysis, the system can detect shock noise through its inherent acoustic properties rather than requiring external mechanical information

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If press-down information and release information are used for shock noise detection, then detection precision is enhanced, but the system requires additional information inputs and becomes more complex

Engineering Contradiction:

Improveshock noise detection precisionVSAvoidinformation input requirements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention enables the noise detection system to identify shock noise using only the noise signal itself through analysis of its intensity change rate and spectral characteristics. The system serves itself by extracting detection information from the acoustic properties of the noise rather than requiring external information inputs about key states, thereby achieving precise detection with minimal input requirements

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The invention extracts the essential detection information directly from the noise signal by analyzing its intensity change rate and frequency spectrum. Instead of using all available information including press-down and release data, the method selectively extracts and utilizes only the critical acoustic characteristics needed for shock noise identification, simplifying the information input requirements while maintaining detection precision

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of manufacture

If averaging operations are used in noise estimation, then the estimation process is simplified, but the ability to detect transient shock noise is lost

Engineering Contradiction:

Improvenoise estimation simplicityVSAvoidshock noise detection accuracy

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention applies partial averaging by computing the average only over a limited recent time window rather than over all available data. This partial action preserves the simplicity of the averaging operation while ensuring that the estimation reflects only recent noise conditions, allowing transient shock noise to be detected through its deviation from the averaged baseline

Inventive Principle:

Principle #16Partial or excessive action

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

Enables effective suppression of shock noise without using shock noise occurrence information, resulting in high-quality emphasized sound output.

Implementation Method 1

A degraded sound signal (signal in which the desired signal and the shock noise coexist) supplied as a sample value sequence to an input terminal 1 of FIG. 34, which is subjected to the transformation such as a Fourier transform in a conversion unit 2

Methodology Applied

Scientific EffectFourier transform:

Data Source

PatentUS9047874B2Noise suppression method, device, and program

Publication Date: 2015.06.02 NEC CORP

AI summary

The noise suppression device includes: a shock noise detection unit which receives an input signal including a shock noise and detects a shock noise according to a change of the input signal; and a shock sound suppression unit which receives the shock sound detection result and the input signal so as to suppress the shock sound.