Pretrained Model Branching for Class-Incremental Learning

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Solution Overview

Problem

Existing methods for extending pretrained machine learning models to recognize additional object classes are time-consuming, expensive, and result in sub-optimal classification accuracies or significant performance reduction for existing classes due to catastrophic forgetting.

Innovation Solution

A two-stage incremental training pipeline is employed, where a pretrained model is extended by adding a new branch near the top to compute scores for new object classes, with a small fusion component to merge outputs and maintain accuracy for both old and new classes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a pretrained model is extended to recognize additional object classes through traditional retraining methods, then the model can identify new classes, but the classification accuracy for existing classes significantly degrades due to catastrophic forgetting

Engineering Contradiction:
Improvecapability to recognize additional object classesVSAvoidclassification accuracy for existing classes
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The model is segmented into multiple independent branches: a base branch that maintains knowledge of original classes and a novel branch that learns new classes. Each branch processes inputs independently and their outputs are combined through a gating mechanism, allowing the model to recognize both old and new classes simultaneously without catastrophic forgetting

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A gating mechanism acts as an intermediary between the base branch and novel branch. The gate dynamically selects and combines outputs from both branches based on the input characteristics, enabling seamless integration of new class knowledge while preserving existing class recognition accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If a new model is built from scratch to recognize new object classes, then the model can be trained efficiently on new data, but it requires separate deployment and combining outputs from multiple models which is complex and sub-optimal

Engineering Contradiction:
Improvetraining efficiency for new classesVSAvoidcomplexity of deploying and combining multiple models
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The base model and novel model are merged into a single unified architecture with shared input processing. The base branch and novel branch are integrated within one model structure, allowing simultaneous recognition of all classes through a single API endpoint, eliminating the need to deploy and coordinate multiple separate models

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If traditional retraining methods are used to extend model capabilities, then the model can learn new classes, but the process is time-consuming and expensive

Engineering Contradiction:
Improvecapability to recognize additional object classesVSAvoidtime required for model extension
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The base model is pre-trained on original classes and frozen to preserve its knowledge. When new classes need to be added, only the novel branch requires training while the base branch remains intact, significantly reducing training time and computational resources compared to retraining the entire model from scratch

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The base branch is copied and used as the foundation for the novel branch. This allows the model to leverage pre-learned features and representations for new classes without retraining the entire model, accelerating the adaptation process while maintaining performance on original classes

Inventive Principle:
Principle #26Copying

Data Source

PatentUS12406469B1Class-incremental learning with pretrained machine learning models
Publication Date: 2025.09.02 AMAZON TECH INC
  • US12406469B1 patent drawing
  • US12406469B1 patent drawing
  • US12406469B1 patent drawing

AI summary

Techniques for class-incremental learning with pretrained machine learning models are described. According to some examples, a pretrained machine learning model that is capable of recognizing objects belonging to a set of object classes is extended to add capability for recognizing additional object classes, without significantly reducing the accuracy of the model for recognizing objects belonging to any of the object classes in the original set of object classes (aka catastrophic forgetting).