Visual Localization via Virtual Views and Projective Transformations

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Solution Overview

Problem

Current visual localization methods for indoor environments face challenges such as limited accuracy, perspective distortion, and the need for extensive reference images, making them inefficient and prone to errors, especially in texture-poor environments with complex geometric variations.

Innovation Solution

A method using pre-computed virtual views generated from sparse reference imagery, leveraging planar regions and projective transformations to create robust localization, allowing for accurate position and orientation determination using content-based image retrieval techniques, even with minimal reference images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Bag-of-Features based image representations are used for localization, then robust description of the scene is achieved, but a huge amount of reference images are required

Engineering Contradiction:
Improverobust descriptionVSAvoidamount of reference images
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent creates virtual copies of reference images by applying projective transformations to generate synthetic views from sparse reference imagery. Instead of capturing every possible viewpoint with physical cameras, the system generates virtual images that simulate appearances from different locations and orientations, thereby reducing the need for extensive physical reference image collection while maintaining robust scene description capabilities

Inventive Principle:
Principle #26Copying

2Extent of automation

If reference images are captured along a single trajectory for mapping, then automated mapping is achieved, but the resolution of position and orientation estimates is drastically limited

Engineering Contradiction:
Improveautomated mappingVSAvoidresolution of position and orientation estimates
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent transitions from a single-trajectory 1D mapping approach to a multi-dimensional virtual viewpoint generation system. By creating virtual images at multiple locations and orientations throughout the 3D space, the system effectively adds spatial dimensions to the reference data, enabling high-resolution position and orientation estimates without requiring physically complex multi-trajectory mapping operations

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If feature descriptors are made robust under perspective distortion, then recall is improved, but precision is reduced due to loss of distinctiveness

Engineering Contradiction:
Improverobustness under perspective distortionVSAvoidprecision of location recognition
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the fundamental parameter of viewpoint representation by generating virtual images with known camera poses and positions. Instead of relying on perspective-distortion-robust feature descriptors that lose distinctiveness, the system uses projective geometry to accurately transform reference images to match query image perspectives, preserving feature distinctiveness while achieving perspective robustness through geometric transformation

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20240169660A1Visual localisation
Publication Date: 2024.05.23 NAVVIS
  • US20240169660A1 patent drawing
  • US20240169660A1 patent drawing
  • US20240169660A1 patent drawing

AI summary

In an embodiment of the invention there is provided a method of visual localization, comprising: generating a plurality of virtual views, wherein each of the virtual views is associated with a location; obtaining a query image; determining the location where the query image was obtained on the basis of a comparison of the query image with said virtual views.