Semi-supervised Medical Image Annotation via Teacher-Student Pseudo-labeling

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Solution Overview

Problem

Existing medical image analysis technologies require extensive frame-level annotations, making it challenging and time-consuming to train AI models for feature localization, especially with limited clinical expertise, and they struggle with using weakly-labeled data which lacks frame-level information necessary for accurate model training.

Innovation Solution

The use of semi-supervised learning models that combine frame-level labeled and weakly-labeled data for training, employing teacher-student learning procedures to generate pseudo-labels and improve prediction performance, allowing for feature localization in medical imaging data like ultrasound videos with reduced annotation needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If frame-level annotations are used for training, then localization accuracy is improved, but annotation time and complexity increase significantly

Engineering Contradiction:
Improvelocalization accuracyVSAvoidannotation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary frame-level localization using a teacher model trained on frame-level annotations, generates pseudo-labels for weakly-labeled videos, and then uses these pseudo-labels to train a student model. This preliminary action allows the student model to achieve good performance without requiring manual frame-level annotation for every video.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Pseudo-labels serve as an intermediary between frame-level annotations and weakly-labeled data. The teacher model generates pseudo-labels from frame-level annotations, which then act as training targets for the student model on weakly-labeled videos, bridging the gap between highly-labeled and weakly-labeled data.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If frame-level annotations are required for all training data, then model training accuracy is improved, but data processing complexity and resource requirements increase

Engineering Contradiction:
Improvemodel training accuracyVSAvoiddata processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The training process is segmented into two distinct phases: a teacher model trained on frame-level annotated data, and a student model trained on weakly-labeled data using pseudo-labels generated by the teacher. This segmentation allows different data types to be processed differently, reducing overall complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the annotation parameter from full frame-level annotations to weak labels (video-level or coarse annotations). By using pseudo-labels generated by the teacher model, the system maintains training effectiveness while dramatically reducing the annotation parameter requirements.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If extensive frame-by-frame annotation is performed, then training data quality is improved, but productivity and efficiency decrease

Engineering Contradiction:
Improvetraining data qualityVSAvoidannotation productivity
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The teacher model serves itself by generating pseudo-labels for the student model's training data. Instead of requiring manual frame-level annotation for every training sample, the system uses the teacher model to automatically generate high-quality pseudo-labels from weak annotations, making the annotation process self-sustaining.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system creates copies of frame-level annotation quality through pseudo-labels generated by the teacher model. These pseudo-labels replicate the quality and detail of manual frame-level annotations without requiring the time-intensive manual process, thus copying the quality benefit without the productivity cost.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS20240404048A1Training medical image annotation models
Publication Date: 2024.12.05 KONINKLIJKE PHILIPS NV
  • US20240404048A1 patent drawing
  • US20240404048A1 patent drawing
  • US20240404048A1 patent drawing

AI summary

Techniques for training models, using weakly-labeled data, to generate predictions based on medical images are disclosed. Models can be trained to perform feature localization, object detection, and/or segmentation. Weakly-labeled data can include unlabeled data or video-level labeled data. Medical imaging data is received including a first set comprising frame-level annotations and a second set comprising weakly-labeled data. A training dataset is generated comprising frame-level ground truth data, and a model is trained, using the training dataset, to generate predictions based on new medical imaging data. In some examples, the training data set may further include weakly-labeled data. In some examples, the training procedure uses a teacher model to generate frame-level localizations (pseudo-labels), which are used to train a student model whose weights can be adaptively transferred to the teacher model. Generated predictions can include frame-level feature localizations and/or video-level annotations.