Recursive Audio Restoration Using Deterministic Degradation

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Solution Overview

Problem

Conventional speech enhancement methods, including diffusion-based models, struggle to effectively handle various types of degradations and often produce low-quality speech, as they rely on stochastic Gaussian noise assumptions that may not be valid for audio waveforms.

Innovation Solution

Employing a deterministic degradation approach using cold diffusion principles, the method iteratively applies a restoration operator and a degradation operator in a recursive process to restore audio signals, adapting the diffusion process to the audio domain by utilizing a neural network trained with machine learning to handle different levels of severity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional diffusion-based models use stochastic Gaussian noise assumptions, then the model can be trained with standard probabilistic frameworks, but the model fails to effectively handle various types of degradations and produces low-quality speech

Engineering Contradiction:
Improvehandling degradation typesVSAvoidspeech quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the fundamental parameter of noise modeling from stochastic Gaussian distribution to deterministic degradation processes. The degradation operator applies controlled, deterministic transformations (such as adding structured noise or applying filters) rather than random Gaussian noise, allowing the model to learn and reverse specific degradation patterns while maintaining high speech quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent inverts the conventional diffusion approach by using deterministic degradation instead of stochastic forward diffusion. Instead of gradually adding random noise and learning to remove it, the method applies controlled deterministic degradation and learns to reverse these specific transformations, which better captures the structure of actual audio degradations

Inventive Principle:
Principle #13The other way round (Inversion)

2Adaptability or versatility

If conventional diffusion models apply stochastic noise in loops, then the training process can be simplified with probabilistic assumptions, but the model cannot adapt to different levels of severity of degradation

Engineering Contradiction:
Improvehandling different degradation levelsVSAvoidtraining process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces dynamic control of degradation severity through the degradation operator, which can adjust the level and type of degradation applied during training and inference. This allows the model to adapt to different degradation levels dynamically without requiring complex retraining procedures, as the operator can be configured for specific severity levels

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If the restoration operator is trained with machine learning to handle different levels of severity, then the model can restore high-quality speech, but the computational cost and training time increase

Engineering Contradiction:
Improvespeech restoration qualityVSAvoidtraining time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action through pre-computed degradation paths and structured training data generation. The degradation operator is designed to apply controlled degradations in advance during training, creating labeled data that directly teaches the restoration operator how to reverse specific degradation patterns, reducing the need for extensive trial-and-error training

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS12609129B2Audio signal enhancement with recursive restoration employing deterministic degradation
Publication Date: 2026.04.21 MITSUBISHI ELECTRIC RESEARCH LABORATORIES INC
  • US12609129B2 patent drawing
  • US12609129B2 patent drawing
  • US12609129B2 patent drawing

AI summary

An audio processing system and method for processing audio is disclosed. The audio processing system collects an input audio signal indicative of degraded measurements of a target audio waveform. The input audio signal is restored with recursive restoration that recursively restores the input audio signal until a termination condition is met. A current iteration of the recursive restoration applies a restoration operator configured to restore a degraded audio signal conditioned on a current level of severity of degradation and degrades the degraded audio signal deterministically with a level of severity less than the current level of severity. A target signal estimate indicative of enhanced measurements of the audio waveform is generated as output.