Sound Processing Apparatus Wireless Echo Cancellation

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Solution Overview

Problem

Existing sound processing techniques fail to effectively remove sound signals from a second microphone that are inputted to a first microphone with delay, leading to echo issues when wireless communication is used.

Innovation Solution

A sound processing apparatus and method that acquire sound signals from both microphones, calculate the time difference and attenuation factor between wireless and air propagation, and perform correction processing to remove the delayed and attenuated sound signal from the first microphone's signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If sound signals from the second microphone are synthesized with the first microphone's signal, then the coverage and sensitivity of sound acquisition is improved, but echo and delayed sound artifacts are introduced

Engineering Contradiction:

Improvesound acquisition sensitivityVSAvoidecho and delayed sound

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful delayed sound signal into a useful reference for echo cancellation. By treating the delayed sound from the second microphone as a known reference signal, the system can generate an echo model and subtract it from the first microphone's signal, thereby eliminating the harmful echo while preserving the beneficial multi-microphone sound acquisition

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent performs preliminary processing on the second microphone's signal by calculating the time difference and attenuation factor before synthesis. This advance preparation allows the system to pre-compute the echo model and attenuation characteristics, enabling effective echo cancellation when the signals are combined, thus preventing echo artifacts from appearing in the final output

Inventive Principle:

Principle #10Preliminary action

2Area of stationary object

If the second microphone is placed at a distance from the first microphone to expand coverage, then the spatial coverage is improved, but the time delay and signal attenuation increase

Engineering Contradiction:

Improvespatial coverageVSAvoidsound propagation delay

Core Design Contradiction:

Area of stationary objectVSLoss of time

Solution Approach 1:

The patent dynamically adjusts the attenuation factor based on the distance between microphones and the acoustic environment. By calculating the appropriate attenuation factor that compensates for distance-related signal loss, the system can effectively combine signals from distant microphones while maintaining proper signal levels and timing relationships

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If wireless communication is used to transmit the second microphone's signal, then the device complexity and wiring are reduced, but time synchronization and signal delay issues arise

Engineering Contradiction:

Improvewiring complexityVSAvoidsignal transmission delay

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The patent implements a feedback mechanism where the time difference between wireless transmission and air propagation is continuously measured and used to adjust the delay compensation. This feedback loop ensures that even as wireless transmission conditions vary, the system maintains accurate time synchronization and effectively cancels echo artifacts

Inventive Principle:

Principle #23Feedback

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

This approach allows for the effective removal of delayed sound signals from the first microphone's signal, reducing echo and improving the quality of synthesized sound signals.

Implementation Method 1

propagation time of a sound from the second position to the first position in air propagation of the sound

Methodology Applied

Scientific EffectSound propagation: Sound

Implementation Method 2

attenuation factor of a sound from the second position to the first position in air propagation of the sound

Methodology Applied

Scientific EffectAttenuation: Absorption (physical)

Implementation Method 3

propagation time of a sound signal from the second position to the first position in the wireless communication of the sound signal

Methodology Applied

Scientific EffectElectromagnetic wave propagation: Electromagnetic Induction

Data Source

PatentUS20250191594A1Sound processing apparatus, sound processing method, and non-transitory computer readable medium

Publication Date: 2025.06.12 CANON KK

AI summary

A sound processing apparatus acquires a first sound signal which is collected at a first position, acquires a second sound signal which is collected at a second position, transmitted from the second position by wireless communication, and received at the first position, acquires a difference between propagation time of a sound signal from the second position to the first position in the wireless communication of the sound signal, and propagation time of a sound from the second position to the first position in air propagation of the sound, acquires an attenuation factor of a sound from the second position to the first position in air propagation of the sound, and removes a third sound signal, which was acquired by attenuating the second sound signal based on the attenuation factor and delaying the second sound signal based on the difference, from the first sound signal.