Simple laser vision sensor calibration for surface profiling applications

Abu-Nabah, Bassam A.; ElSoussi, Adnane O.; Alami, Abed ElRahman K. Al

doi:10.1016/j.optlaseng.2016.03.024

Cited by 25 publications

(11 citation statements)

References 18 publications

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“…The core technology, i.e., structured light triangulation, has been advanced for more than 30 years [29]. During this period, there have been many practical discussions on engineering application, but most of them focus on the measurement of the geometric morphology of the parts, such as the measurement of the geometric shape of parts [16,30], weld detection [5,18]. In recent years, the combination of the line structured light triangulation method and robotic technology has further promoted the automation of measurement.…”

Section: Experimental Scheme and Measurement Principlementioning

confidence: 99%

“…Consequently, this paper presents a method of laser scanning to improve the measurement robustness that can be applied in practical engineering. However, the technology of laser scanning, or named structured light triangulation focus more on the measurement of the geometric shape of the object itself, such as welding detection [16,17,18], geomorphological detection [19], and three-dimensional reconstruction [20]. So far, however, only a small volume of work has been published about pose measurement for cylindrical parts by laser scanning.…”

Section: Introductionmentioning

confidence: 99%

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An Improved Robust Method for Pose Estimation of Cylindrical Parts with Interference Features

Zhang

Qiu

et al. 2019

Sensors

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Horizontal docking assembly is a fundamental process in the aerospace assembly, where intelligent measurement and adjustable support systems are urgently needed to achieve higher automation and precision. Thus, a laser scanning approach is employed to obtain the point cloud from a laser scanning sensor. And a method of section profile fitting is put forward to solve the pose parameters from the data cloud acquired by the laser scanning sensor. Firstly, the data is segmented into planar profiles by a series of parallel planes, and ellipse fitting is employed to estimate each center of the section profiles. Secondly, the pose of the part can be obtained through a spatial straight line fitting with these profile centers. However, there may be some interference features on the surface of the parts in the practical assembly process, which will cause negative effects to the measurement. Aiming at the interferences, a robust method improved from M-estimation and RANSAC is proposed to enhance the measurement robustness. The proportion of the inner points in a whole profile point set is set as a judgment criterion to validate each planar profile. Finally, a prototype is fabricated, a series of experiments have been conducted to verify the proposed method.

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Section: Experimental Scheme and Measurement Principlementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Improved Robust Method for Pose Estimation of Cylindrical Parts with Interference Features

Zhang

Qiu

et al. 2019

Sensors

View full text Add to dashboard Cite

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“…3(a) (e.g., according to Ref. 18). The exemplary viewing direction onto the displayed triangulation setup is indicated in Fig.…”

Section: Virtual Triangulation Sensormentioning

confidence: 99%

Full simulation model for laser triangulation measurement in an inhomogeneous refractive index field

et al. 2018

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The optical inspection of wrought hot workpieces between subsequent forming steps of a multistage process chain can yield diverse advantages. Deficient components can be detected in an early forming stage. Moreover, the eliminated cooling economizes heating energy. The present workpiece temperature can be exploited in the following chain steps. Challenges arise due to the heat input into the air surrounding the workpiece, as triangulation techniques rely on homogeneous optical conditions. The effect of an inhomogeneous refractive index field (RIF) in air on a 3-D geometry measurement by optical triangulation is modeled exemplary by a virtual measurement of a hot cylinder. To our knowledge, this is the first simulation approach that fully considers both light deflection from the illumination unit to object and from object to camera. Simulated measurement results in a homogeneous and an inhomogeneous RIF are compared. The presented approach predicts measurement deviations in inhomogeneous optical media and can help to design actuated or computer-assisted compensation routines in order to reduce deflection effects when measuring hot objects.

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“…The basic idea of the laser plane calibration is taken from Abu-Nabah et al. 4 To be able to gain multiple sectional views of the measurement object, the object has been attached to a precise transitional stage by Newport 5 and is moved between consecutive images. To stitch the acquired measurement data correctly, the transitional stage has been calibrated by taking an image of the calibration pattern in every stage position (2), surface measurement zone (3) and temperature measurement locations (4.1) and (4.2).…”

Section: Triangulation Sensormentioning

confidence: 99%

Light section measurement to quantify the accuracy loss induced by laser light deflection in an inhomogeneous refractive index field

Beermann

Quentin

Posch

et al. 2017

Optical Measurement Systems for Industrial Inspection X

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In the manufacturing process of Tailored Forming components, the inline inspection of the joining zone directly after each single process step can yield advantages -such as early error detection and real-time process control. Since measuring times need to be synchronized with the production chain, there is no time to cool down the components in between two hot forming processes. On the one hand, the chosen measurement technique needs to be non-tactile due to the heat of the measurement object. On the other hand, the object's areal surface texture needs to be captured rapidly to realize a fast inline inspection. These requirements are only matched by optical 3d measurement systems. Additional challenges arise due to the high temperature of the Tailored Forming components: the ambient air is heated up and the air's temperature increase results in an inhomogeneous refractive index field surrounding the hot workpiece, effecting the light's path emitted by the illumination unit of the optical sensor. We present a simple measurement setup based on the laser light section method to visualize the measurement accuracy loss induced by the convectional heat flow from a hot cylindrical measurement object. To attain a direct validation of the measurement results, the measurements are performed with and with reduced influence of the inhomogeneous refractive index field induced by the hot object.

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Simple laser vision sensor calibration for surface profiling applications

Cited by 25 publications

References 18 publications

An Improved Robust Method for Pose Estimation of Cylindrical Parts with Interference Features

An Improved Robust Method for Pose Estimation of Cylindrical Parts with Interference Features

Full simulation model for laser triangulation measurement in an inhomogeneous refractive index field

Light section measurement to quantify the accuracy loss induced by laser light deflection in an inhomogeneous refractive index field

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