Adaptive Inter-Channel Time Difference Estimation for Noisy Audio
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Solution Overview
Problem
Existing methods for determining inter-channel time difference (ICTD) in multi-channel audio signals are inaccurate in noisy environments and fail to provide stable estimation, especially when audio components overlap or are affected by background noise, leading to unstable modeling of spatial audio scenes.
Innovation Solution
An adaptive method is employed to determine inter-channel time difference by using an adaptive inter-channel correlation threshold based on cross-correlation functions, where the threshold is adjusted according to the inter-channel correlation, ensuring only relevant ICTD values are used, thereby stabilizing the estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional cross-correlation methods are used to determine ICTD, then the process is simple and fast, but the accuracy and stability deteriorate in noisy environments and when audio components overlap
Solution Approach 1:
The patent applies dynamics by making the correlation threshold adaptive rather than fixed. The threshold dynamically adjusts based on the estimated ICTD value and signal characteristics, allowing the system to maintain high accuracy across varying noise conditions and audio scenarios without requiring complex manual tuning for each situation.
Solution Approach 2:
The patent changes the parameter of the correlation threshold from a static value to a dynamically adjusted parameter. By modifying the threshold based on ICTD estimates and signal analysis, the system achieves robust performance in noisy and overlapping audio conditions while keeping the overall processing framework relatively simple.
2Stability of the object's composition
If a fixed correlation threshold is used, then the processing is straightforward, but the stability of ICTD estimation deteriorates when audio components overlap or noise is present
Solution Approach 1:
The patent implements feedback by using the estimated ICTD value to adjust the correlation threshold for subsequent processing. This closed-loop approach continuously refines the threshold based on actual signal characteristics, ensuring stable ICTD estimation even when audio components overlap or background noise is present, without requiring complex external control systems.
Solution Approach 2:
The patent applies preliminary action by performing initial signal analysis and ICTD estimation to establish an appropriate correlation threshold before the main processing occurs. This preparatory step ensures that the threshold is optimally set for the specific audio conditions, providing stable estimation throughout the subsequent processing without requiring complex real-time adjustments.
3Measurement precision
If adaptive threshold adjustment is implemented, then ICTD estimation accuracy improves in noisy conditions, but the processing time and computational load increase
Solution Approach 1:
The patent applies partial action by implementing adaptive threshold adjustment only in specific frequency bands or time frames where it is most beneficial, rather than uniformly across the entire signal. This selective approach maintains high accuracy in noisy and overlapping conditions while minimizing the additional computational burden and processing time.
Data Source
AI summary
A method and device are disclosed for determining an inter-channel time difference of a multi-channel audio signal having at least two channels. A determination is made at a number of consecutive time instances, inter-channel correlation based on a cross-correlation function involving at least two different channels of the multi-channel audio signal. Each value of the inter-channel correlation is associated with a corresponding value of the inter-channel time difference. An adaptive inter-channel correlation threshold is adaptively determined based on adaptive smoothing of the inter-channel correlation in time. A current value of the inter-channel correlation is then evaluated in relation to the adaptive inter-channel correlation threshold to determine whether the corresponding current value of the inter-channel time difference is relevant. Based on the result of this evaluation, an updated value of the inter-channel time difference is determined.