Variable Moire Pattern Marker for Accurate Posture Estimation

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Solution Overview

Problem

Existing planar visual markers for estimating the position and posture of objects in three-dimensional space lack the accuracy comparable to the Global Positioning System (GPS), leading to suboptimal precision in such measurements.

Innovation Solution

The implementation of high-sensitivity variable moire patterns with a shorter cycle and enhanced sensitivity, combined with a multi-step visual line angle estimation method using both standard and high-sensitivity patterns to achieve more accurate posture and position estimation, involves the use of rectangular-shaped moire patterns with reference points and lenticular lenses, and employs a nonlinear optimization method to minimize reprojection errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If existing planar visual markers are used for position and posture estimation, then the system is simple and easy to implement, but the measurement accuracy is insufficient and cannot reach GPS-level precision

Engineering Contradiction:
Improveposition and posture estimation accuracyVSAvoidmarker pattern complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The marker is divided into multiple functional regions: a first moire pattern region with standard sensitivity for general posture estimation, and a second moire pattern region with high sensitivity for precise visual line angle measurement. This segmentation allows each region to specialize in different measurement tasks, achieving high overall accuracy without requiring the entire marker to be overly complex

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the marker are assigned different qualities: the first moire pattern region uses a standard cycle suitable for broad coverage, while the second moire pattern region uses a shorter cycle for enhanced sensitivity in specific areas. This local differentiation optimizes measurement accuracy where needed while maintaining overall system simplicity

Inventive Principle:
Principle #3Local quality

2Measurement precision

If high-sensitivity variable moire patterns with shorter cycle are used, then the visual line angle estimation accuracy is improved, but the marker design and manufacturing become more complex

Engineering Contradiction:
Improvevisual line angle estimation accuracyVSAvoidmoire pattern fabrication accuracy
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

Instead of making the entire marker with high-sensitivity patterns, only a partial region (the second moire pattern region) uses the shorter cycle for enhanced sensitivity. This partial application provides sufficient accuracy improvement for the visual line angle estimation without requiring the entire manufacturing process to achieve the stringent precision levels needed for a complete high-sensitivity marker

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If a multi-step estimation method using both standard and high-sensitivity patterns is employed, then the position and posture estimation accuracy is significantly enhanced, but the computational processing time and complexity increase

Engineering Contradiction:
Improveposition and posture estimation accuracyVSAvoidcomputational processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system first uses the first moire pattern region to obtain a preliminary posture estimation, which provides an initial visual line angle value. This preliminary result is then refined using the second high-sensitivity moire pattern region. This preliminary action approach avoids starting from scratch with complex calculations, reducing overall processing time while achieving high accuracy

Inventive Principle:
Principle #10Preliminary action

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 significantly enhances the accuracy of posture and position estimation, providing a more precise determination of object position and posture by leveraging the higher sensitivity and shorter cycle of high-sensitivity moire patterns and iterative error minimization techniques.

Implementation Method 1

plane rectangular-shaped high-sensitivity variable moire patterns VH1 and VH2... provided on the same plane as that of the AR marker 2

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

high-sensitivity variable moire patterns with a shorter cycle and enhanced sensitivity

Methodology Applied
Scientific EffectMoiré Effect: Moiré Effect

Data Source

PatentEP3550259B1Marker and posture estimation method using marker
Publication Date: 2021.11.10 NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE & TECHNOLOGY
  • EP3550259B1 patent drawingFigure 1~2
  • EP3550259B1 patent drawingFigure 3~4A
  • EP3550259B1 patent drawingFigure 4B~5

AI summary

A marker for achieving more accurate position and posture estimation, and a posture estimation method and a position and posture estimation method using this marker are provided. In order to solve this problem, the present invention provides a marker for estimating the posture of an object, wherein the marker includes standard variable moire patterns VS1 and VS2 for estimating a visual line angle around at least one axis with respect to the object and high-sensitivity variable moire patterns VH1 and VH2 that have a resolution of visual line angle higher than the standard variable moire patterns VS1 and VS2 and that are used to estimate the visual line angle around the axis.