Object Classifier Neural Networks With Two-Phase Coarse-to-Fine Training

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Solution Overview

Problem

Autonomous vehicles face challenges in accurately classifying objects using neural networks, as existing systems degrade in coarse-object classification performance when transitioning from coarse to fine-object classification tasks, leading to reduced accuracy and increased computational inefficiency.

Innovation Solution

A two-phase training method for object classification neural networks, where the first phase optimizes coarse-object classifications and the second phase refines fine-object classifications by freezing parameters of channel encoder subnetworks not involved in fine-object classification, ensuring minimal degradation of coarse-object classification capabilities and efficient training.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the neural network is trained to perform fine-object classification, then the fine-object classification accuracy is improved, but the coarse-object classification performance degrades

Engineering Contradiction:
Improvefine-object classification accuracyVSAvoidcoarse-object classification performance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The neural network is divided into multiple independent channel encoder subnetworks, each responsible for processing specific object categories. This segmentation allows the network to specialize in fine-object classification for certain categories while maintaining robust coarse-object classification capabilities across all categories, resolving the performance degradation issue.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the neural network are assigned different functions: some channel encoder subnetworks are optimized for fine-object classification while others maintain general coarse-object classification capabilities. This local differentiation allows the system to achieve high fine-object accuracy without sacrificing overall coarse-object performance.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If all parameters are adjusted during fine-object classification training, then the fine-object classification is optimized, but the training computational overhead increases

Engineering Contradiction:
Improvefine-object classification accuracyVSAvoidtraining efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent extracts and freezes the parameters of channel encoder subnetworks that are not involved in fine-object classification during the second training phase. This extraction approach allows training to focus only on the necessary subsets of parameters, significantly reducing computational overhead while maintaining fine-object classification accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of adjusting all parameters during fine-object classification training, the system applies partial action by only adjusting parameters of channel encoder subnetworks relevant to the specific fine-object category being trained. This selective parameter adjustment reduces training computational overhead while achieving the desired optimization.

Inventive Principle:
Principle #16Partial or excessive action

3Device complexity

If the neural network is designed for coarse-object classification only, then the system complexity is low, but the system cannot perform fine-object classification

Engineering Contradiction:
Improveneural network structureVSAvoidclassification capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The neural network is designed with multiple channel encoder subnetworks that can serve different functions: some are optimized for coarse-object classification while others are specialized for fine-object classification. This multi-functional design allows the system to perform both coarse and fine-object classification without requiring separate independent systems, balancing complexity and versatility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS11361187B1Neural networks for coarse- and fine-object classifications
Publication Date: 2022.06.14 WAYMO LLC
  • US11361187B1 patent drawing
  • US11361187B1 patent drawing
  • US11361187B1 patent drawing

AI summary

Aspects of the subject matter disclosed herein include methods, systems, and other techniques for training, in a first phase, an object classifier neural network with a first set of training data, the first set of training data including a first plurality of training examples, each training example in the first set of training data being labeled with a coarse-object classification; and training, in a second phase after completion of the first phase, the object classifier neural network with a second set of training data, the second set of training data including a second plurality of training examples, each training example in the second set of training data being labeled with a fine-object classification.