3D Reference Object for Measuring System Calibration

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Solution Overview

Problem

Existing methods for checking surveying systems, such as dental measurement systems, require precise known dimensions and involve high technical effort to determine calibration and registration accuracy, making it difficult to determine if the accuracy is within permitted tolerance limits.

Innovation Solution

A method involving multiple three-dimensional recordings of a reference object from different directions, where the object is rotated and measured twice, allowing for the determination of measurement errors by comparing the distance between initial and final recording positions, without requiring known dimensions, and enabling automated measurement with overlapping recording areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a reference model with known dimensions is measured and compared with laboratory system measurements, then measurement accuracy can be determined, but the technical effort and complexity increase significantly

Engineering Contradiction:
Improvecalibration and registration accuracyVSAvoidtechnical effort
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The measurement system checks itself by comparing the measured distance with the predefined correct distance stored in the system, eliminating the need for external laboratory system measurements and complex comparison procedures

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The correct distance between two characteristic points is predetermined and stored in the system before measurement, allowing direct comparison with the measured distance without requiring external reference measurements

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If multiple three-dimensional recordings are taken and registered, then measurement errors can be detected, but the process becomes more complex and time-consuming

Engineering Contradiction:
Improveerror detection capabilityVSAvoidchecking time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The method extracts only the essential information needed for error detection - the distance between two characteristic points - from the complex three-dimensional recordings, avoiding the need for comprehensive surface comparison

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Characteristic points are predetermined and their correct distance is stored in advance, allowing direct comparison with measured values without requiring complex post-processing of the entire three-dimensional model

Inventive Principle:
Principle #10Preliminary action

3Loss of information

If false color markings and mean value calculations are used to show deviations, then visual representation is improved, but the complexity and technical effort increase

Engineering Contradiction:
Improvedeviation visualizationVSAvoidprocessing complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The method extracts only the distance between two characteristic points from the complex three-dimensional deviation data, providing essential error information without requiring complex visualization procedures

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2807450B1Method and reference model for checking a measuring system
Publication Date: 2020.02.26 SIRONA DENTAL SYSTEMS GMBH CORP LEGAL
  • EP2807450B1 patent drawingFigure 1~2
  • EP2807450B1 patent drawingFigure 3~4
  • EP2807450B1 patent drawingFigure 5

AI summary

The invention relates to a reference object (3) and a method for checking a measuring system (1), wherein a plurality of three-dimensional recordings (4, 8) of a reference object are recorded from different recording directions (5) by means of the measuring system (1). The reference object (3) has a closed shape, wherein each of the three-dimensional recordings (4) is registered with at least the preceding recording (4). In the case of a faulty calibration and/or in the case of a faulty registration, the individual recordings (4, 8) are deformed compared to the actual shape of the reference object (3), so that the deformation continues when assembling the individual three-dimensional recordings (4) to form an overall recording (54) and the generated overall recording (54) deviates in its dimensions from the dimensions of the reference object (3) as a result thereof. At least one object region (10) of the reference object (3) is measured twice, at the beginning of a circuit and at the end of the circuit, wherein a distance (55) is determined in the overall recording (54) between a first position of the object region (10) in a first recording at the beginning of the circuit and a second position of the object region (10) in a second recording at the end of the circuit.