Room Impulse Response Estimation for Acoustic Echo Cancellation

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Solution Overview

Problem

Acoustic echo cancellation in reverberant environments with microphone arrays is inefficient as existing methods compute each echo cancellation filter separately without exploiting the array structure, leading to suboptimal impulse response estimates.

Innovation Solution

The proposed method estimates the room transfer function by incorporating array information, using a sparse array signal processing algorithm that models audible signal reflections as virtual image sources and exploits the sparsity of reflections to form improved impulse response estimates between loudspeakers and microphones, thereby enhancing echo cancellation performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional methods compute each echo cancellation filter separately for each microphone, then the implementation is simple, but the impulse response estimation accuracy deteriorates

Engineering Contradiction:
Improveimpulse response estimation accuracyVSAvoidalgorithm complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the echo cancellation filter computations for all microphones into a single unified algorithm. Instead of computing separate filters for each microphone independently, the method processes the microphone array signals jointly, exploiting the spatial correlations and shared acoustic environment to produce more accurate impulse response estimates while maintaining computational efficiency.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If traditional methods ignore the array structure, then the algorithm is simpler, but the echo cancellation performance deteriorates

Engineering Contradiction:
Improveecho cancellation performanceVSAvoidalgorithm complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a unified algorithm that serves multiple microphones simultaneously, making the echo cancellation system multi-functional. The single algorithm processes signals from the entire microphone array, extracting shared acoustic information and spatial characteristics to improve echo cancellation performance across all microphones while avoiding the need for separate specialized algorithms for each microphone.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If separate filter computation is used for each microphone, then computational resources per microphone are lower, but overall processing efficiency deteriorates

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidcomputational resources
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent merges the computational tasks for all microphones into a single integrated processing pipeline. By computing echo cancellation filters for the entire microphone array simultaneously rather than separately for each microphone, the method reduces redundant computations and improves overall processing efficiency while maintaining reasonable computational resource requirements.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3078210B1Estimating a room impulse response for acoustic echo cancelling
Publication Date: 2018.01.17 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3078210B1 patent drawingFigure 1
  • EP3078210B1 patent drawingFigure 2
  • EP3078210B1 patent drawingFigure 3

AI summary

Various methods and systems for estimating a room impulse response between an audio source and an array of microphones are described. In one example, a method includes receiving audio signals at a microphone of an array of microphones. The audio signals correspond to each of the microphones in the array of microphones. The method also includes determining a room impulse response in a subspace that is compatible with a geometry of the array of microphones based on the received audio signals.