Marker Plane Correction for Accurate Robot Teaching

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Solution Overview

Problem

Existing marker detection systems, particularly those using two-dimensional cameras, suffer from positional deviations due to lens distortion and viewing angle issues, leading to inaccurate marker detection and subsequent robot operation errors.

Innovation Solution

A marker detection apparatus that combines 2D image data with 3D point group data to accurately determine the position of markers by superimposing point group data onto image data, correcting marker positions using plane detection and projection techniques to enhance accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a two-dimensional camera is used to detect the marker, then the device complexity is reduced, but the measurement precision deteriorates due to lens distortion and viewing angle position effects

Engineering Contradiction:
Improvecamera systemVSAvoidmarker position detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary processing system that captures images from multiple cameras at different positions and angles, then uses image processing to synthesize a corrected marker position that compensates for lens distortion and viewing angle effects. This intermediary processing layer mediates between the simple camera system and the required high precision measurement.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transitions from two-dimensional image data to three-dimensional spatial information by using multiple cameras positioned at different locations. The system reconstructs the marker's three-dimensional position and orientation by processing images from multiple viewpoints, thereby overcoming the limitations of single-plane two-dimensional detection.

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

2Device complexity

If image data alone is used for marker detection, then the device complexity is low, but the measurement precision is insufficient due to contour deviation and image distortion

Engineering Contradiction:
Improvedetection systemVSAvoidmarker position accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent merges multiple image data sets from different cameras and combines them with three-dimensional coordinate information. By integrating data from multiple sources and processing channels, the system achieves higher measurement precision while keeping the individual detection components relatively simple.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system implements feedback processing where the detected marker position and orientation are continuously refined through iterative image processing and coordinate transformation. The processed results are fed back to correct and improve the accuracy of marker detection by compensating for distortions and deviations.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4177837B1Marker detection apparatus and robot teaching system
Publication Date: 2025.12.10 DAIHEN CORP
  • EP4177837B1 patent drawingFigure 1
  • EP4177837B1 patent drawingFigure 2
  • EP4177837B1 patent drawingFigure 3

AI summary

Provided is a marker detection apparatus able to detect the position of a marker with high accuracy and a robot teaching system using the same. A marker detection apparatus includes: an image generation unit that superimposes point group data, acquired by a 3D camera and photographed from a viewpoint same as a viewpoint of a 2D camera, on image data acquired by the 2D camera, thereby generating a combined image; a marker position calculation unit that detects a marker and calculates a position of the marker on a basis of the image data; a plane detection unit that detects a plane on a basis of the point group data; a marker plane determination unit that determines a marker plane on a basis of point group data included in a region of the marker detected from the position of the marker calculated by the marker position calculation unit and the plane detected by the plane detection unit; and a marker position correction unit that projects the position of the marker, calculated by the marker position calculation unit, onto the marker plane, thereby correcting the position of the marker.