Camera Pose Determination via Single Marker and Polarization

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Solution Overview

Problem

Current methods for determining the pose of two cameras relative to each other, such as marker-based systems and laser tracking, face limitations in accuracy and robustness, especially in dynamic environments, and are susceptible to mechanical deformations and complex marker installations.

Innovation Solution

A procedure that uses simple markers, either passive or active, to determine the pose of one camera relative to another in six degrees of freedom, employing image processing, light-time measurement, and polarization techniques, allowing for high accuracy and robustness against mechanical influences, and enabling fast measurement rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If marker-based methods with multiple markers are used to determine camera pose, then measurement accuracy can be improved, but device complexity and susceptibility to mechanical deformation increase

Engineering Contradiction:
Improvepose determination accuracyVSAvoidmarker installation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential function of pose determination from complex multi-marker systems and implements it using a single marker with simplified features. The single marker contains sufficient information (fiducial markers, asymmetry) to determine all six degrees of freedom of camera pose, eliminating the need for multiple markers and their complex spatial relationships.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The single marker design serves multiple functions simultaneously: it provides reference features for triangulation, contains asymmetric elements for orientation determination, and eliminates the need for precise inter-marker spacing. This universal marker design replaces the entire multi-marker system while maintaining or improving measurement accuracy.

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

2Measurement precision

If multiple markers spaced far apart are used for accurate measurements, then pose determination accuracy improves, but ease of operation and robustness against deformation worsen

Engineering Contradiction:
Improvelocalization accuracyVSAvoidmarker installation ease
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent removes the requirement for multiple spaced markers and extracts only the essential localization function into a single marker. This single marker can be placed at any convenient location on the target object, greatly simplifying installation while maintaining accurate pose determination through its internal feature geometry.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If triangulation-based methods are used for pose determination, then implementation simplicity improves, but measurement accuracy for orientation and distance worsens

Engineering Contradiction:
Improvemethod implementation simplicityVSAvoidorientation and distance accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent introduces asymmetric features within the single marker design. The marker contains symmetric fiducial markers for basic triangulation plus additional asymmetric elements (such as asymmetric patterns or positioned features) that provide reference information for determining orientation in all three rotational degrees of freedom, thereby improving orientation and distance accuracy while keeping the implementation simple.

Inventive Principle:
Principle #4Asymmetry

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for precise and robust determination of camera pose with high measurement rates, independent of marker position stability, making it suitable for dynamic applications and rough environments, and can handle all degrees of freedom with improved accuracy compared to existing methods.

Implementation Method 1

employing image processing, light-time measurement, and polarization techniques

Methodology Applied
Scientific EffectImage processing: Image Processing

Implementation Method 2

light-time measurement

Methodology Applied
Scientific EffectTime of flight measurement: Time of Flight

Implementation Method 3

polarization techniques

Methodology Applied
Scientific EffectPolarization: Polarisation

Data Source

PatentEP4443388B1Determining a pose of a first camera relative to a second camera
Publication Date: 2025.01.29 SICK AG
  • EP4443388B1 patent drawingFigure 1~2
  • EP4443388B1 patent drawingFigure 3~4
  • EP4443388B1 patent drawingFigure 5~6

AI summary

A method for determining the pose of a first camera (10a) relative to a second camera (10b) is described, wherein the cameras (10a-b) are located within each other's respective field of view (18) and each captures at least one image, and wherein the pose is determined by evaluating the images. The first camera (10a) has a first marker and the second camera (10b) has a second marker; the position of each marker in the captured images is located, and from each position, two angles of orientation of the capturing camera (10a-b) are determined.