Audio Signal Segmentation for Non-Stationary Noise Reduction
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Solution Overview
Problem
In loudspeaker calibration, repeated measurements are often necessary to improve signal-to-noise levels, but these repetitions cannot eliminate artifacts caused by time-variances and non-linear distortions, especially due to non-stationary noise like clicks and pops.
Innovation Solution
An apparatus and method for combining three or more audio signals by segmenting each signal into overlapping segments, applying an analysis window function to produce temporally weighted segments, determining weight values for each segment based on noise variance or root mean square values, calculating a weighted average of these segments, and generating an output signal using a synthesis window function and overlap-add method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If repeated measurements are performed to improve signal-to-noise level, then measurement precision is improved, but non-stationary noise and artifacts from time-variances cannot be eliminated
Solution Approach 1:
The audio signal is divided into multiple overlapping segments, each processed independently with window functions. This segmentation allows noise and artifacts in specific time regions to be identified and suppressed while preserving the signal in other segments, thereby reducing non-stationary noise effects while maintaining measurement precision.
Solution Approach 2:
The patent applies dynamic weight values to different segments based on their noise characteristics. By calculating weights that reflect the reliability of each segment (lower weights for segments with clicks, pops, or high noise), the system adaptively combines segments to minimize the impact of non-stationary noise while preserving signal quality.
2Object-affected harmful factors
If conventional click and pop de-noising algorithms are used, then non-stationary noise is reduced, but measurement accuracy may be compromised due to artifact introduction
Solution Approach 1:
The patent introduces an intermediary weighting mechanism that operates between raw signal segments and the final combined output. Instead of directly modifying segments to remove noise (which may introduce artifacts), the weight determination block acts as an intermediary that selectively attenuates noisy segments while preserving clean segments, maintaining measurement accuracy.
Solution Approach 2:
The patent converts the presence of noise and artifacts into useful information for weight determination. By analyzing noise variance and signal characteristics in each segment, the system identifies which segments contain harmful elements and assigns them lower weights, thereby using the noise characteristics themselves to guide the noise reduction process without introducing additional artifacts.
Data Source
AI summary
An apparatus for combining three or more audio signals is described. The apparatus includes a segmentation block for segmenting each audio signal into segments, a weight determination block, which is configured to determine a weight value for each of the temporally weighted audio signal segments, a combination block for combining the temporally weighted audio signal segments of each audio signal, and a synthesis block for generating an output audio signal. A method for combining three or more audio signals and a computer program product are also described.