Contrastive Representation Learning for Semantic Correspondence

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Solution Overview

Problem

Conventional methods for training neural networks for semantic correspondence in images rely on supervised learning with labeled data, which is labor-intensive and limited, and pretrained networks struggle to adapt to new domains, leading to poor generalization.

Innovation Solution

A multi-level contrastive training strategy that uses contrasting image pairs to learn semantic correspondences at the image and pixel levels without requiring keypoint or bounding box labels, employing image-level and pixel-level contrastive losses to update the neural network parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If supervised training with labeled data (keypoints and bounding boxes) is used, then the neural network can learn semantic correspondence, but the training process becomes labor-intensive and the amount of training data is limited

Engineering Contradiction:
Improvesemantic correspondence accuracyVSAvoidtraining data preparation effort
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent employs self-supervised learning where the neural network learns semantic correspondence from unlabeled image pairs by automatically generating its own training signals through contrastive learning. The system compares feature representations of corresponding regions across image pairs and optimizes without requiring manual keypoint or bounding box annotations, making the training process self-sufficient and eliminating labor-intensive data preparation

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses feature representation copying and comparison across image pairs. It extracts and compares feature vectors from corresponding regions in different images, using the copied feature representations to learn semantic correspondence relationships without needing labeled data. This copying approach allows the system to leverage unlabeled training data efficiently

Inventive Principle:
Principle #26Copying

2Productivity

If a pretrained neural network is used, then training can start with existing knowledge, but the network does not easily adapt to domains or categories different from training data

Engineering Contradiction:
Improvetraining efficiencyVSAvoiddomain generalization capability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent employs contrastive loss optimization that dynamically adjusts network parameters to maximize feature discrimination between corresponding and non-corresponding regions. By changing the optimization objective from classification accuracy to feature representation similarity, the network adapts to learn domain-specific correspondence patterns that generalize across different categories and domains

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a dynamic contrastive learning framework where the training objective and feature representations are continuously adapted during training. The system dynamically adjusts feature extraction and comparison based on the specific image pairs and domains encountered, enabling flexible adaptation to different categories without retraining from scratch

Inventive Principle:
Principle #15Dynamics

3Reliability

If manual labeling is used to provide training data, then the neural network can be trained, but the variety and amount of training data is limited

Engineering Contradiction:
Improvetraining data qualityVSAvoidamount of training data
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The system generates its own training signals through self-supervised contrastive learning, automatically creating positive and negative training pairs from unlabeled image data. This self-service approach eliminates the bottleneck of manual labeling while maintaining training quality through carefully designed contrastive objectives that guide learning from abundant unlabeled data

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS11960570B2Learning contrastive representation for semantic correspondence
Publication Date: 2024.04.16 NVIDIA CORP
  • US11960570B2 patent drawing
  • US11960570B2 patent drawing
  • US11960570B2 patent drawing

AI summary

A multi-level contrastive training strategy for training a neural network relies on image pairs (no other labels) to learn semantic correspondences at the image level and region or pixel level. The neural network is trained using contrasting image pairs including different objects and corresponding image pairs including different views of the same object. Conceptually, contrastive training pulls corresponding image pairs closer and pushes contrasting image pairs apart. An image-level contrastive loss is computed from the outputs (predictions) of the neural network and used to update parameters (weights) of the neural network via backpropagation. The neural network is also trained via pixel-level contrastive learning using only image pairs. Pixel-level contrastive learning receives an image pair, where each image includes an object in a particular category.