Self-Supervised Cross-Modal Learning for Road Defect Detection

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Solution Overview

Problem

Current methods for analyzing road infrastructure conditions, such as rut-level estimation and crack detection, rely on manual annotation and are inefficient due to the need for labeled data, limiting their scalability and accuracy when using multiple sensor modalities like visual images and LiDAR data.

Innovation Solution

A self-supervised pre-training approach using unlabeled datasets from multiple sensor modalities is employed to generate a backbone model, followed by fine-tuning with a limited set of labeled data, allowing for the combination of semantic and geometric understanding of road scenes for defect detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If manual annotation is used for training, then model training can be performed, but the process is inefficient and lacks scalability

Engineering Contradiction:
Improvetraining efficiencyVSAvoidtime for manual annotation
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The system uses self-supervised learning where the model learns from unlabeled data by predicting relationships between different sensor modalities (e.g., predicting LiDAR data from camera images and vice versa). This eliminates the need for manual annotation while still enabling effective model training through self-generated supervision signals from the data itself.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If labeled data is required for training, then accurate defect detection can be achieved, but the availability of labeled data is limited

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidamount of labeled data
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The system performs preliminary pre-training on large amounts of unlabeled data using self-supervised learning to learn general features and relationships between sensor modalities. After this preliminary action, the model is then fine-tuned with a smaller amount of labeled data, which significantly improves defect detection accuracy while reducing the bottleneck of limited labeled data availability.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If multiple sensor modalities are used, then comprehensive road scene understanding is achieved, but the complexity of processing increases

Engineering Contradiction:
Improvemulti-modal understanding capabilityVSAvoidprocessing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system merges multiple sensor modalities (camera images, LiDAR point clouds, etc.) into a unified representation space through self-supervised pre-training. By learning cross-modal relationships during pre-training, the model integrates information from different sensors in a cohesive manner, reducing processing complexity while maintaining comprehensive road scene understanding capabilities.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS20240071105A1Cross-modal self-supervised learning for infrastructure analysis
Publication Date: 2024.02.29 NEC LABORATORIES AMERICA INC
  • US20240071105A1 patent drawing
  • US20240071105A1 patent drawing
  • US20240071105A1 patent drawing

AI summary

Methods and systems for training a model include pre-training a backbone model with a pre-training decoder, using an unlabeled dataset with multiple distinct sensor data modalities that derive from different sensor types. The backbone model is fine-tuned with an output decoder after pre-training, using a labeled dataset with the multiple modalities.