Visual Localization Training With Synthetic Images for Extreme Domain Shifts

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Solution Overview

Problem

Visual localization systems in autonomous robots face challenges in accurately estimating camera pose due to extreme domain shifts caused by changes in lighting conditions, occlusions, weather, and seasonal variations, leading to unreliable navigation.

Innovation Solution

Utilize generative AI models to generate synthetic images simulating domain shifts, validate these images using geometric filters, and enhance the training of image retrieval models with a contrastive loss function and domain randomization to improve resilience to environmental changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If visual localization uses pure visual information from camera images, then the system can operate autonomously without external sensors, but the system becomes sensitive to environmental changes such as lighting conditions, occlusions, weather, and seasonal variations

Engineering Contradiction:
Improveautonomous operationVSAvoidlocalization accuracy
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-training the image retrieval model using synthetic images that simulate various environmental conditions (different lighting, weather, seasons, occlusions) before deployment. This pre-training prepares the model to handle domain shifts in real-world scenarios, improving reliability while maintaining autonomous operation without external sensors.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the image retrieval model is trained only on real images from the environment, then the training data is authentic, but the model fails to generalize under extreme domain shifts and environmental variations

Engineering Contradiction:
Improvelocalization accuracyVSAvoidrobustness to domain shifts
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent uses copying by generating synthetic images that replicate real environmental scenes under various conditions (different lighting, weather, seasons). These synthetic copies are used to augment the training dataset, enabling the model to learn invariant features and generalize better to domain shifts while maintaining localization precision on real images.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent applies parameter changes by systematically varying environmental parameters in synthetic image generation (lighting conditions, weather patterns, seasonal changes, occlusion levels). This creates a diverse training dataset that teaches the model to maintain localization accuracy across different parameter configurations and domain shifts.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If synthetic images are generated to augment training data, then the model's robustness to domain shifts improves, but the training process becomes more complex involving generative models and validation

Engineering Contradiction:
Improverobustness to environmental changesVSAvoidtraining process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses an intermediary approach by introducing a validation mechanism that checks geometric consistency between synthetic and real images. This intermediary validation step ensures that only high-quality synthetic images that preserve geometric relationships are used for training, managing complexity while maintaining reliability improvements.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If geometric validation is applied to synthetic images, then the quality and consistency of training data improves, but the validation process requires additional computational resources and time

Engineering Contradiction:
Improvetraining data qualityVSAvoidvalidation processing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies local quality by performing geometric validation selectively on critical regions of synthetic images rather than uniformly across all images. This focuses computational resources on validating the most important geometric relationships while reducing overall validation time and processing requirements.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS20250209784A1Leveraging synthetic images to improve visual localization in case of extreme domain shifts
Publication Date: 2025.06.26 NAVER CORP
  • US20250209784A1 patent drawing
  • US20250209784A1 patent drawing
  • US20250209784A1 patent drawing

AI summary

The system and method to improve image retrieval models in case of extreme domain shifts for long term visual localization. An initial dataset of real images of an environment can be obtained from an image database that may comprise of matching pairs and sets of non-matching images. The initial dataset is augmented with synthetic variants of each image to represent the potential changing conditions of the environment. The synthetic variants may be generated by using generative AI models. To validate synthetic images, a geometric consistency score is calculated for each synthetic pair based on a degree of geometric correspondence between images of the synthetic pair. A subset of k synthetic tuples is selected from a set of tuples corresponding to a matching pair, either randomly or based on the geometric consistency score, to compute a contrastive loss function for training of image retrieval model along with other custom/disclosed settings.