3D Measurement Device Using Two-Fold Rotational Symmetrical Patterned Light

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Solution Overview

Problem

Existing three-dimensional measurement methods using structured light require significant computational resources for template matching, especially when using random dot patterns, and lack flexibility in projecting unit design.

Innovation Solution

A three-dimensional measurement method employing a two-fold rotational symmetrical patterned light, where the pattern is projected onto a measurement target, allowing for efficient calculation of three-dimensional positions using a diffractive optical element or mask, and enabling flexible design of the projecting unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a random dot pattern is used for three-dimensional measurement, then the measurement can be performed with structured light, but the amount of computation required for template matching increases significantly

Engineering Contradiction:
Improvethree-dimensional measurement precisionVSAvoidcomputation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the pattern parameter from a random dot pattern to a two-fold rotational symmetrical pattern. This parameter change maintains the structured light measurement capability while significantly reducing template matching computation, as the symmetrical structure allows for more efficient pattern recognition and matching algorithms.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a specific symmetrical structure (two-fold rotational symmetry) that breaks the randomness of the dot pattern. This structured asymmetry provides unique orientation information that reduces computational complexity while maintaining measurement precision, as the symmetrical properties can be exploited for faster pattern matching.

Inventive Principle:
Principle #4Asymmetry

2Ease of manufacture

If a conventional projecting unit design is used, then the structure is simple, but the flexibility and adaptability of the measurement system is limited

Engineering Contradiction:
Improveprojecting unit manufacturing simplicityVSAvoidprojecting unit design flexibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent segments the projecting unit into a light source and a separate pattern generation component (mask or diffractive optical element). This segmentation allows independent optimization of each component, maintaining manufacturing simplicity while enabling flexible pattern design through different mask or DOE configurations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a mask or diffractive optical element as an intermediary between the light source and the measurement target. This intermediary component enables flexible pattern projection without complicating the overall system, as it can be easily replaced or adjusted to change the projected pattern while keeping the light source and other components unchanged.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reduces computational complexity and enhances the flexibility of the projecting unit design, achieving more effective and precise three-dimensional measurements with improved precision, wide field of view, and lower costs compared to existing methods.

Implementation Method 1

employing a two-fold rotational symmetrical patterned light, where the pattern is projected onto a measurement target, allowing for efficient calculation of three-dimensional positions using a diffractive optical element or mask

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

capturing means for capturing the measurement target onto which the patterned light is projected

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3527936B1Three-dimensional measurement device and three-dimensional measurement method
Publication Date: 2021.12.15 OMRON CORP
  • EP3527936B1 patent drawingFigure 1A~1B
  • EP3527936B1 patent drawingFigure 1C
  • EP3527936B1 patent drawingFigure 2

AI summary

A three-dimensional measurement apparatus includes: projecting means for projecting, onto a measurement target, patterned light having a two-dimensionally coded pattern in which a plurality of types of words each having a different two-dimensional structure and being distinguishable from each other are two-dimensionally arranged; capturing means for capturing the measurement target onto which the patterned light is projected; and calculating means for calculating a three-dimensional position of a target pixel of the image from an image captured by the capturing means, and the two-dimensionally coded pattern is two-fold symmetrical. The two-dimensionally coded pattern is a pattern in which a predetermined word is repeated in the column direction for each column. It is preferable that a word in the k-th column from one end is a word obtained by rotating a word in the k-th column from the other end by 180°. Also, it is preferable that the projecting means generates patterned light using a diffractive optical element.