Respiratory Sound Classification via Self-Supervised Contrastive Pre-Training

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Solution Overview

Problem

Current methods for diagnosing respiratory conditions like COVID-19 using respiratory sounds face challenges due to the need for labeled data, high annotation costs, and privacy concerns, limiting the effectiveness and applicability of fully-supervised approaches.

Innovation Solution

A self-supervised learning framework that uses a contrastive pre-training phase to learn robust numerical representations of respiratory sounds without labeled data, followed by a classification phase with a pre-trained feature encoder and ensemble architecture, reducing reliance on labeled data and improving classification performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If fully-supervised learning methods are used for respiratory sound classification, then classification accuracy can be improved, but annotation costs and dependency on labeled data increase

Engineering Contradiction:
Improveclassification accuracyVSAvoidlabeled data requirement
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent applies contrastive pre-training as a preliminary action before the main classification task. The feature encoder is first pre-trained on unlabeled respiratory sounds using contrastive learning to learn robust representations, then fine-tuned with labeled data for classification. This two-stage approach reduces the amount of labeled data needed while maintaining high classification accuracy.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If more labeled data is collected for training, then classification performance improves, but privacy concerns and annotation costs worsen

Engineering Contradiction:
Improveclassification performanceVSAvoidprivacy concerns
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs self-service learning by utilizing unlabeled respiratory sounds for contrastive pre-training. The model learns meaningful features from unlabeled data itself, reducing dependency on externally annotated labeled data. This self-supervised approach maintains high performance while minimizing privacy concerns associated with collecting and storing labeled patient data.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If traditional supervised training is used, then model convergence is achieved, but training time and computational resources increase due to data preprocessing

Engineering Contradiction:
Improvemodel convergenceVSAvoidtraining time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The contrastive pre-training phase serves as a preliminary action that prepares the feature encoder with robust representations before the main classification training. This pre-training on unlabeled data accelerates convergence during fine-tuning with labeled data, reducing overall training time and computational resources required.

Inventive Principle:
Principle #10Preliminary action

4Quantity of substance

If unlabeled data is used for training, then annotation costs decrease, but classification accuracy may deteriorate

Engineering Contradiction:
Improveannotation costVSAvoidclassification accuracy
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent uses unlabeled data for contrastive pre-training as a preliminary step to learn robust feature representations. This pre-training on unlabeled data does not compromise final classification accuracy because it is followed by fine-tuning with a small amount of labeled data, achieving both low annotation costs and high accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the training parameter from requiring labeled data to using unlabeled data for the pre-training phase. By adjusting the training strategy to contrastive learning on unlabeled data followed by fine-tuning, the model achieves robust feature learning without annotation costs, maintaining high classification accuracy.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20240341715A1Method and systems for respiratory sound classification
Publication Date: 2024.10.17 NEWSOUTH INNOVATIONS PTY LTD
  • US20240341715A1 patent drawing
  • US20240341715A1 patent drawing
  • US20240341715A1 patent drawing

AI summary

Described embodiments relate to methods, systems, and computer-readable media for training a feature encoder for encoding sound samples, such as respiratory sounds. Some embodiments further relate to methods, systems, and computer-readable media for training an audio classifier, such as a respiratory sound classifier, using the pre-trained feature encoder. Some embodiments relate to methods, systems, and computer-readable media for classifying a sample of an audio file, such as a respiratory sound, as being a positive example or a negative example of a condition, such as a respiratory condition.