Echo Suppression Device Using Nonlinear Echo Estimation
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Solution Overview
Problem
Conventional echo suppression techniques face difficulties in stably suppressing nonlinear echo signals in microphone input signals, particularly in hands-free call systems and video conferences, due to the use of linear models that fail to accurately estimate nonlinear echoes.
Innovation Solution
An echo suppression device is configured with a first linear echo suppression unit to estimate and suppress linear echoes, a nonlinear echo estimation unit to model and estimate nonlinear echoes using a nonlinear echo model, and a second linear echo suppression unit to further suppress residual linear echoes, with the option to utilize a neural network for improved estimation precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional linear echo suppression techniques are used, then linear echoes can be suppressed, but nonlinear echo signals cannot be stably suppressed
Solution Approach 1:
The echo suppression device is divided into multiple functional units: a first linear echo suppression unit for handling linear echoes, a nonlinear echo estimation unit for modeling nonlinear echoes, and a second linear echo suppression unit for residual suppression. This segmentation allows each unit to specialize in specific echo types, improving overall suppression reliability without requiring a single complex model to handle all cases.
Solution Approach 2:
The patent transitions from using only linear models to incorporating nonlinear echo models that can adaptively change parameters based on input signal characteristics. The nonlinear echo estimation unit uses models that can represent complex nonlinear relationships, allowing the system to adapt to different echo conditions while maintaining stability in suppressing nonlinear echo signals.
2Reliability
If nonlinear echo models are introduced to suppress nonlinear echoes, then suppression effectiveness improves, but computational complexity and power consumption increase
Solution Approach 1:
By segmenting the processing into distinct linear and nonlinear components, the system can apply computationally efficient linear suppression first, then use the more complex nonlinear estimation only where needed. This reduces overall computational burden compared to applying a full nonlinear model to all signals.
Solution Approach 2:
The nonlinear echo estimation is applied selectively rather than uniformly across all frequency ranges and time periods. The system focuses computational resources on segments where nonlinear echoes are most problematic, maintaining suppression effectiveness while reducing total power consumption.
Data Source
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AI summary
An echo suppression device includes an echo canceller which suppresses a linear echo signal from an input signal acquired by a microphone; a nonlinear echo estimation unit which, by using a nonlinear echo model indicative of a relationship between at least one of a call reception signal to be output to a speaker and the input signal, and a nonlinear echo signal, estimates the nonlinear echo signal included in the input signal from at least one of the call reception signal and the input signal; a nonlinear echo suppression unit which, by using the estimated nonlinear echo signal, suppresses the nonlinear echo signal from an output signal of the echo canceller; and an echo suppressor which suppresses a residual linear echo signal not suppressed by the echo canceller from an output signal of the nonlinear echo suppression unit.