2D Code Calibration for 3D Triangulation Cameras

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Solution Overview

Problem

The existing calibration methods for three-dimensional optical measurement cameras using triangulation are prone to errors due to inaccuracies in marker positions on calibration sets, requiring serial number identification and database searches, which can be cumbersome and error-prone.

Innovation Solution

A method that uses a two-dimensional code, such as a QR code, on the calibration set, which is read by the camera to directly obtain calibration data or a code number for database retrieval, eliminating the need for manual serial number entry and reducing errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a calibration set with markers is used for camera calibration, then the calibration process can be performed, but reading and entering the serial number manually introduces errors and reduces efficiency

Engineering Contradiction:
Improvecalibration accuracyVSAvoidmanual data entry
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces the manual mechanical process of reading and entering serial numbers with an automated optical recognition system. A camera captures an image of the calibration set, and image processing software automatically extracts the serial number or calibration data from the image, eliminating manual data entry and reducing errors.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The calibration set is designed to be self-identifying through visual markers or codes that contain calibration information. The system automatically reads this information from the calibration set itself without requiring external manual intervention, making the calibration process self-service oriented.

Inventive Principle:
Principle #25Self-service

2Ease of manufacture

If marker positions on the calibration set are used for calibration, then calibration can be performed, but production variations cause position inaccuracies

Engineering Contradiction:
Improvecalibration set productionVSAvoidmarker position accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent measures and records the actual positions of markers on the calibration set during manufacturing or initial setup, storing this information in a database. This preliminary measurement compensates for production variations, allowing the calibration process to use accurate reference positions even when physical marker positions vary due to manufacturing tolerances.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Instead of relying directly on physical marker positions that may vary, the patent creates a digital copy or model of the calibration set with precise marker positions stored in a database. This digital replica serves as the reference for calibration, eliminating errors from physical manufacturing variations.

Inventive Principle:
Principle #26Copying

3Reliability

If a database search is performed to retrieve calibration data, then accurate calibration can be obtained, but the process becomes time-consuming

Engineering Contradiction:
Improvecalibration data accuracyVSAvoidcalibration speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent pre-organizes calibration data in a database with unique identifiers that match the visual codes on calibration sets. During calibration, the system quickly retrieves the corresponding data using the automatically recognized code, eliminating time-consuming manual database searches while maintaining data accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces manual database searching with automated image recognition and data retrieval systems. The camera captures the calibration set code, software automatically processes the image to extract the identifier, and the system instantly retrieves the corresponding calibration data from the database, dramatically speeding up the process.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 simplifies the calibration process by allowing the camera to automatically read and process the code, ensuring accurate calibration data retrieval without manual database searches, thus reducing errors and enhancing the precision of three-dimensional optical measurements.

Implementation Method 1

The code is illuminated by the camera's white light source

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

Cameras for the three-dimensional measurement of objects by means of triangulation are based on scanning the object with light, with an illumination beam path and an observation beam path forming an angle

Methodology Applied
Scientific EffectTriangulation:

Data Source

PatentEP3077765B1Method for reading a two-dimensional code by means of a camera used for three-dimensional optical measurement of objects
Publication Date: 2018.09.26 SIRONA DENTAL SYSTEMS GMBH CORP LEGAL
  • EP3077765B1 patent drawingFigure 1~2
  • EP3077765B1 patent drawingFigure 3~4

AI summary

Disclosed is a method for reading a two-dimensional code (17) by means of a camera (1) used for the three-dimensional optical measurement of an object using triangulation. Said method comprises the steps of placing the camera (1) above the two-dimensional code (17), having a white light source (5) of the camera (1) illuminate the code (17), having the camera (1) capture an image (18) of the code (17), and having an arithmetic unit (6) read data encrypted in the code (17) from the image (18) of the code (17).