Acoustic Transform Optimization for Phase-Aware Source Separation

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Solution Overview

Problem

Current signal processing techniques, particularly in sound source enhancement, face challenges in handling complex numbers due to the difficulty of operating phase spectra, often limiting processing to real number domains or ignoring phase information, which hampers complete signal reconstruction.

Innovation Solution

The approach involves designing a general transform function P with an inverse transform, optimized simultaneously with the neural network for signal processing, allowing for error backpropagation and enabling the use of complex transforms like STFT or MDCT, and treating the transform as an optimizable function with parameters θP, alongside the signal processing parameters θM, to enhance sound source separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If STFT transform is used for signal analysis, then frequency domain processing capability is improved, but handling complexity increases due to complex numbers

Engineering Contradiction:
Improvefrequency domain processing capabilityVSAvoidhandling complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a complex number operation unit as an intermediary component that专门 handles complex number operations in the STFT processing chain. This mediator handles the complex arithmetic between the transform unit and signal processing unit, isolating the complexity handling from the main processing flow and making the system more manageable despite using complex numbers.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If phase spectrum processing is performed, then signal reconstruction accuracy is improved, but operational difficulty increases

Engineering Contradiction:
Improvesignal reconstruction accuracyVSAvoidoperational difficulty
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent segments the signal processing into distinct functional units: a transform unit for STFT, a complex number operation unit for handling complex arithmetic including phase operations, and an inverse transform unit for reconstruction. This segmentation allows phase spectrum processing to be performed in a dedicated unit, improving reconstruction accuracy while managing operational difficulty through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The complex number operation unit serves as an intermediary that facilitates phase spectrum processing. It receives complex spectral data, performs phase-related operations, and passes results to subsequent processing stages, thereby enabling accurate signal reconstruction while shielding the rest of the system from the complexity of direct phase manipulation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If transform processing is fixed, then processing speed is improved, but adaptability to different signal types deteriorates

Engineering Contradiction:
Improveprocessing speedVSAvoidadaptability to different signal types
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic adaptability by allowing the transform parameters (such as window size, overlap factor, and transform type) to be adjusted based on the characteristics of the input signal. The system can adaptively select processing parameters to optimize performance for different signal types while maintaining efficient processing through the established transform pipeline.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11798571B2Acoustic signal processing apparatus, method and program for the same
Publication Date: 2023.10.24 NIPPON TELEGRAPH & TELEPHONE CORP
  • US11798571B2 patent drawing
  • US11798571B2 patent drawing
  • US11798571B2 patent drawing

AI summary

Provided is an acoustic signal processing technique for performing a signal transformation suitable for desired signal processing (e.g., sound source enhancement processing) on a signal, and then performing the desired signal processing on the transformed signal. An acoustic signal processing device performs signal processing M which is a desired target on an input acoustic signal x. The acoustic signal processing device includes a transform unit that performs transform processing P on the acoustic signal x to obtain a first transform coefficient X; a signal processing unit that performs signal processing M corresponding to a desired target on the first transform coefficient X to obtain a second transform coefficient {circumflex over ( )}S; and an inverse transform unit that performs inverse transform processing P−1 on the second transform coefficient {circumflex over ( )}S to obtain an acoustic signal {circumflex over ( )}s subjected to signal processing which is a desired target, wherein the transform processing P, the inverse transform processing P−1, and the signal processing M are simultaneously optimized.