Acoustic Echo Suppression Device with System Variation Detection

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Solution Overview

Problem

Existing acoustic echo suppression systems in vehicles face challenges in maintaining sound quality due to variations in seating arrangements and environmental changes, such as passenger movements or window openings, leading to inadequate echo cancellation and deteriorated sound output.

Innovation Solution

An acoustic echo suppression device with two filter processors and a system variation detector that adaptively adjusts echo suppression signals based on detected changes in the environment, using adaptive filters and reference signals to select the appropriate suppression voice signal for output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transmission characteristics are prepared in advance for each seating arrangement pattern, then echo cancellation works well for fixed seating patterns, but the system cannot adapt to sudden environmental changes such as passenger movements or window openings

Engineering Contradiction:

Improveecho cancellation accuracyVSAvoidadaptability to environmental changes

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic adaptability by introducing a system variation detector that monitors environmental changes in real-time. When changes are detected (such as passenger movements or window openings), the system automatically switches from pre-measured transmission characteristics to dynamically estimated characteristics, ensuring continuous echo cancellation effectiveness despite environmental variations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs feedback mechanisms where the detector continuously monitors the acoustic environment and provides information about system variations. This feedback loop enables the system to adjust its echo cancellation strategy by selecting appropriate transmission characteristics based on current conditions, thereby maintaining reliability across changing environments.

Inventive Principle:

Principle #23Feedback

2Device complexity

If pre-measured transmission characteristics are used, then the system is simple to implement, but the sound quality deteriorates when transmission characteristics deviate from actual sound field conditions

Engineering Contradiction:

Improvesystem implementation complexityVSAvoidsound quality

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The system maintains simplicity for normal operation using pre-measured transmission characteristics but dynamically transitions to more complex real-time estimation only when necessary. This dynamic approach balances implementation complexity with sound quality by activating advanced processing only during environmental variations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The detector acts as an intermediary that determines when to switch between simple pre-measured characteristics and complex dynamically estimated characteristics. This intermediary mechanism allows the system to maintain simplicity during stable conditions while ensuring sound quality during variations without requiring complex processing to be always active.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If the system uses fixed transmission characteristics, then processing is computationally efficient, but echo suppression accuracy decreases when environmental conditions change suddenly

Engineering Contradiction:

Improveprocessing efficiencyVSAvoidecho suppression accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system dynamically adjusts processing efficiency by using computationally efficient pre-measured characteristics during stable periods and switching to more intensive real-time estimation only when environmental changes are detected. This dynamic processing strategy maintains high efficiency while ensuring accuracy when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs periodic monitoring through the detector to identify environmental changes, triggering real-time estimation only during necessary intervals. This periodic action pattern allows the system to maintain processing efficiency during normal operation while ensuring measurement precision during critical moments when echo suppression accuracy is compromised by environmental variations.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS10798247B2Acoustic echo suppression device and acoustic echo suppression method

Publication Date: 2020.10.06 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A microphone picks-up voice of a driver. A first echo suppression unit outputs a voice signal after first echo suppression based on a voice signal of the driver and a voice signal after echo suppression in the past (first reference signal) stored in a buffer memory. A second echo suppression unit outputs a voice signal after second echo suppression based on a voice signal of the driver and a voice signal after the echo suppression in the past (second reference signal) stored in a buffer memory. An output signal selector selects one of the voice signals after the first echo suppression or the voice signal after the second echo suppression according to a detection result of the presence or absence of a system variation by a system variation detector, and causes a speaker to output the selected voice signal.