Display-Screen Camera Calibration for Optical Inspection Precision

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Solution Overview

Problem

Current optical inspection systems require complex and costly calibration targets for precise parameter determination, limiting their use to maintenance operations and increasing costs.

Innovation Solution

An optical inspection installation with a system that uses a display screen to project calibration and test patterns, allowing for geometric, sharpness, and radiometric calibration of cameras, integrated into the camera setup for periodic use, reducing the need for separate targets and lowering costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional calibration targets are used for precise parameter determination, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improveparameter determination precisionVSAvoidcalibration target complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses a digital copy of the calibration pattern displayed on a screen instead of a physical calibration target. The camera captures images of the displayed pattern, and software processes these images to determine calibration parameters. This digital copying approach eliminates the need for complex physical targets while maintaining measurement precision.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/physical calibration target system with an electronic display and software-based image processing system. The calibration pattern is generated and displayed digitally, and the calibration calculations are performed through software algorithms rather than requiring complex physical target structures.

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

2Measurement precision

If traditional calibration targets are used for precise parameter determination, then measurement precision is improved, but cost increases

Engineering Contradiction:
Improveparameter determination precisionVSAvoidcalibration target cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent uses a digital copy of the calibration pattern displayed on a screen instead of a physical calibration target. The camera captures images of the displayed pattern, and software processes these images to determine calibration parameters. This digital copying approach eliminates the need for complex physical targets while maintaining measurement precision.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent employs a standard display screen and software algorithms that are inexpensive compared to precision-manufactured physical calibration targets. The digital calibration pattern can be regenerated indefinitely without degradation, eliminating the need for costly replacement of physical targets.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If complex calibration targets are used, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improveparameter determination precisionVSAvoidcalibration operation simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system performs calibration automatically by capturing images of the displayed pattern and processing them through software algorithms. The computer-controlled movement system positions the camera relative to the display screen, and the software automatically calculates calibration parameters without requiring manual intervention or complex target handling.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical/physical calibration target system with an electronic display and software-based image processing system. The calibration pattern is generated and displayed digitally, and the calibration calculations are performed through software algorithms rather than requiring complex physical target structures.

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

Data Source

PatentEP3350581B1Calibration or test pattern
Publication Date: 2023.11.08 VIT SA
  • EP3350581B1 patent drawingFigure 1~3
  • EP3350581B1 patent drawingFigure 4~6

AI summary

The invention relates to a facility (10) for the optical inspection of an object, comprising at least one camera (18), a screen (30) for displaying images, a system (24, 32) for moving the display screen and/or the camera, which is used to bring the display screen into the field of vision of the camera, and a system (20) for controlling the display screen and the camera so that the camera is able to acquire at least one image displayed by the display screen.