Laser-Camera Coordinate Calibration Using 3D Light Point Measurement
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Solution Overview
Problem
Existing laser machining apparatuses face challenges in achieving highly accurate calibration of the radiation position due to potential positional errors between the specified and actual radiation positions, making it difficult to align the laser coordinate system with the camera coordinate system accurately.
Innovation Solution
A calibration method and apparatus that utilize a laser scanner and cameras to radiate calibration laser light in a predetermined pattern, measure three-dimensional positions of light points, and calculate the positional relationship between the scanner and camera coordinate systems, allowing for accurate calibration by determining the laser-light control origin and base vectors, thereby aligning the systems accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a laser machining apparatus uses a coordinate system for specifying radiation positions, then the apparatus can control laser radiation locations, but positional errors occur between specified and actual radiation positions making accurate calibration difficult
Solution Approach 1:
A calibration plate with known marker positions serves as an intermediary object between the laser apparatus and camera coordinate systems. The plate provides reference markers that enable accurate determination of the relationship between the two coordinate systems, eliminating direct alignment difficulties.
Solution Approach 2:
The patent replaces mechanical alignment methods with optical measurement methods. Instead of mechanically fixing or aligning the laser and camera systems, the invention uses optical imaging of calibration markers to mathematically determine coordinate system relationships, achieving higher precision without mechanical constraints.
2Manufacturing precision
If mechanical fixation methods are used to align coordinate systems, then alignment can be achieved, but the process becomes complex and costly
Solution Approach 1:
The invention replaces complex mechanical fixation and alignment apparatus with a simplified optical measurement system. A camera captures images of calibration markers on a plate, and software calculates coordinate transformations, eliminating the need for complex mechanical alignment devices.
Solution Approach 2:
The calibration plate creates a known geometric copy or reference framework that can be imaged and measured. The markers on the plate represent known positions that serve as a reference copy for establishing coordinate relationships, simplifying the calibration process without requiring direct mechanical contact or complex apparatus.
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 ensures highly accurate calibration of the laser and camera coordinate systems, eliminating the need for mechanical fixation and reducing costs, while improving the reliability and accuracy of the calibration process.
Implementation Method 1
radiating, using the laser scanner, calibration laser light having a predetermined pattern in the scanner coordinate system
Implementation Method 2
taking, using the camera, images of the light points projected on the surface of the plate
Data Source
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AI summary
A calibrating method is for calibrating a laser coordinate system of a laser radiator and a camera coordinate system of a camera. The method includes radiating, using the laser radiator, calibration laser light to an object such that the laser light has a predetermined pattern in the laser coordinate system. A first position of the object is changed to a second position with light points of the laser light projected on a surface of the object. A first image and a second image of the light points are taken using the camera with the object located at the first and second positions. A positional relationship between the coordinate systems is calculated based on three-dimensional positions of the light points in the camera coordinate system. The three-dimensional positions have been obtained based on the first and second images.