Plane-constraint-based calibration method for a galvanometric laser scanner

Yang, Ming; Zeng, Liangcai; Jiang, Jun; Yu, Cheng-Yi

doi:10.1177/1687814018773670

Cited by 8 publications

(4 citation statements)

References 25 publications

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“…In the literature, much research has reported the calibration of galvanometric scanning systems. For instance, Mao et al [8] and Yang et al [9] reported the calibration of one-mirror galvanometric scanners, which were used in 3D measurement systems. Lüdtke et al [10] and Tu et al [11] calibrated two-mirror galvanometric laser scanners by using employed statistical learning methods (e.g., linear regression and artificial neural networks).…”

Section: Literature Reviewmentioning

confidence: 99%

In situ calibration of galvanometric scanning head for laser powder bed fusion machines based on a vision system

Quinsat

2020

Int J Adv Manuf Technol

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In Laser Powder Bed Fusion (LPBF) additive manufacturing machines, a laser galvanometric scanning system is used to control the movement of the laser beam, which melts material powders layer-by-layer in a powder bed. Errors between desirable positions and actual positions of the laser in the work plane of the machine directly affect the geometry accuracy of built parts. Therefore, calibrating the laser galvanometric scanning system of LPBF machines is a very important task. This system is generally calibrated by calculating correction tables for its joint components. However, most existing calibration methods require a measuring phase of actual positions of laser engraved on a calibration plate. This phase was generally performed by a measuring system in another location, thus requiring a delay time and causing an interruption of the calibration process. In the current study, an in-situ calibration method for the laser galvanometric scanning head of LPBF machines was developed based on a vision system. The vision system (i.e., a high-resolution monochrome camera) was used to acquire experimental data rapidly during the calibration process, thereby avoiding the laser marking and the measuring phases of laser marks in another location. The acquired experimental data was subsequently used to calculate the correction tables/matrices for calibrating the optical chain of an LPBF machine prototype. The obtained results show that the developed measurement method is acceptable for the in-situ measurement with a good accuracy. After the calibration process, errors between the positions generated by the identified LPBF machine and those measured by the proposed method are very small with an average error of 0.03 mm, and about 80% of positions present an error less than 0.04 mm in the calibration region.

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Section: Literature Reviewmentioning

confidence: 99%

In situ calibration of galvanometric scanning head for laser powder bed fusion machines based on a vision system

Quinsat

2020

Int J Adv Manuf Technol

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“…Similar to the one-step calibration method, an invariance of cross-ratio (Zhou et al, 2005) or double cross-ratio (Wei et al, 2003) based approach is also employed to generate control points in two-step calibration method. Mao et al (2018) proposed a plane-constraint based calibration approach to effective and highly accurate extraction of much more control points for a structured light stripe vision sensor. There are also some methods that the 3D calibration target is constituted by a 2D calibration target and a movable platform (Li et al, 2008; Luo et al, 2014; Xie et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

A one-step calibration method without redundant parameters for a laser stripe sensor

Mao,

He,

et al. 2024

AIEDAM

Self Cite

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A laser stripe sensor has two kinds of calibration methods. One is based on the homography model between the laser stripe plane and the image plane, which is called the one-step calibration method. The other is based on the simple triangular method, which is named as the two-step calibration method. However, the geometrical meaning of each element in the one-step calibration method is not clear as that in the two-step calibration method. A novel mathematical derivation is presented to reveal the geometrical meaning of each parameter in the one-step calibration method, and then the comparative study of the one-step calibration method and the two-step calibration method is completed and the intrinsic relationship is derived. What is more, a one-step calibration method is proposed with 7 independent parameters rather than 11 independent parameters. Experiments are conducted to verify the accuracy and robust of the proposed calibration method.

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“…These laser scanners appear in several applications [28][29][30][31][32] due to their "good characteristics of high deflection speed, high positioning repeatability and concise structure" [25]. For the majority of the publications, the authors restrict their analysis to situations where a 2M-GLS measures a plane or a two-dimensional surface [33]. In such situations, there is no need to go beyond point-based calibrations.…”

Section: Introductionmentioning

confidence: 99%

On the Angular Control of Rotating Lasers by Means of Line Calculus on Hyperboloids

Penne

Boi

Vanlanduit

2023

Sensors

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We propose a new paradigm for modelling and calibrating laser scanners with rotation symmetry, as is the case for lidars or for galvanometric laser systems with one or two rotating mirrors. Instead of bothering about the intrinsic parameters of a physical model, we use the geometric properties of the device to model it as a specific configuration of lines, which can be recovered by a line-data-driven procedure. Compared to universal data-driven methods that train general line models, our algebraic-geometric approach only requires a few measurements. We elaborate the case of a galvanometric laser scanner with two mirrors, that we model as a grid of hyperboloids represented by a grid of 3×3 lines. This provides a new type of look-up table, containing not more than nine elements, lines rather than points, where we replace the approximating interpolation with exact affine combinations of lines. The proposed method is validated in a realistic virtual setting. As a collateral contribution, we present a robust algorithm for fitting ruled surfaces of revolution on noisy line measurements.

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Plane-constraint-based calibration method for a galvanometric laser scanner

Cited by 8 publications

References 25 publications

In situ calibration of galvanometric scanning head for laser powder bed fusion machines based on a vision system

In situ calibration of galvanometric scanning head for laser powder bed fusion machines based on a vision system

A one-step calibration method without redundant parameters for a laser stripe sensor

On the Angular Control of Rotating Lasers by Means of Line Calculus on Hyperboloids

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