Modeling the Influence of Oil Film, Position and Orientation Parameters on the Accuracy of a Laser Triangulation Probe

Wu, Chengxing; Chen, Baijin; Yang, Chunsheng; Yan, Xiaopeng

doi:10.3390/s19081844

Cited by 7 publications

(4 citation statements)

References 30 publications

(30 reference statements)

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“…The coherent nature of laser light in combination with the roughness of the measurement surface leads to so-called speckles in the laser spot image, resulting in a measurement error [16,47,48]. Additionally, the wide range of possible surfaces with different optical properties [17,49,50] as well as the probes position and orientation towards the measurement surface limit the accuracy of LTDs [51].…”

Section: Error Model In a Laser Triangulation Systemmentioning

confidence: 99%

Optical Setup for Error Compensation in a Laser Triangulation System

Kienle

Batarilo

Akgül

et al. 2020

Sensors

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Absolute distance measurement is a field of research with a large variety of applications. Laser triangulation is a well-tested and developed technique using geometric relations to calculate the absolute distance to an object. The advantages of laser triangulation include its simple and cost-effective setup with yet a high achievable accuracy and resolution in short distances. A main problem of the technology is that even small changes of the optomechanical setup, e.g., due to thermal expansion, lead to significant measurement errors. Therefore, in this work, we introduce an optical setup containing only a beam splitter and a mirror, which splits the laser into a measurement beam and a reference beam. The reference beam can then be used to compensate for different error sources, such as laser beam dithering or shifts of the measurement setup due to the thermal expansion of the components. The effectiveness of this setup is proven by extensive simulations and measurements. The compensation setup improves the deviation in static measurements by up to 75%, whereas the measurement uncertainty at a distance of 1 m can be reduced to 85 μm. Consequently, this compensation setup can improve the accuracy of classical laser triangulation devices and make them more robust against changes in environmental conditions.

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Section: Error Model In a Laser Triangulation Systemmentioning

confidence: 99%

Optical Setup for Error Compensation in a Laser Triangulation System

Kienle

Batarilo

Akgül

et al. 2020

Sensors

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show abstract

“…To solve this problem, much research has been done on enhancing the ability to adapt to the external interference of the laser measure. The influence of oil film, position and orientation parameters on the accuracy of a laser triangulation probe was reported in [11]. It corrected the effect of oil film on accuracy in structured light laser measurement.…”

Section: Introductionmentioning

confidence: 99%

Repair Method of Data Loss in Weld Surface Defect Detection Based on Light Intensity and 3D Geometry

Shiyi

Xing

2020

IEEE Access

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Weld surface quality inspection is an indispensable part in the welding automation engineering. When Laser Triangulation Method (LTM) is used to scan the weld surface, external factors will interfere with the laser center line, resulting in data loss and quality detection failure, and massive data loss is difficult to be repaired in the traditional way. In order to improve the quality of weld surface defect detection, it is necessary to find an effective and strong anti-interference method to fix the lost data. This paper presents a method of fixing the data loss caused by external environmental factors in the process of detecting flatbed lap weld surface defects by LTM. The paper includes the analysis of the causes of data loss, its impact for practical applications and a repair method. The repair method derives a formula which is suitable for expressing three-dimensional points on weld surface by combining Bidirectional Reflectance Distribution Function (BRDF) and weld surface section model. The accuracy of the algorithm is verified by experiments on standard block and single weld cross-section. The accuracy of the method up to 92% and the repair rate improved by 30%. The method was tested on flatbed lap weld to confirm its effectiveness in the field of catching surface defects hidden in the lost data.

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“…Sometimes, the contact probe cannot reach the narrow corners in the coordinate measuring machine (CMM) or stylus profiler [6,7]. By contrast, the optical sensors can help to provide better solutions for these problems, such as laser triangulation, laser interferometry, grating interferometry, and CCT, to name but a few [8,9,10]. Laser triangulation is popular in many commercial applications with relatively high accuracy and ability to be integrated.…”

Section: Introductionmentioning

confidence: 99%

Chromatic Confocal Displacement Sensor with Optimized Dispersion Probe and Modified Centroid Peak Extraction Algorithm

Bai

Wang

et al. 2019

Sensors

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Chromatic confocal technology (CCT) is one of the most promising methods for the contactless and accurate measurement of structure profiles. Based on the principles of chromatic dispersion and confocal theory, a dispersion probe is proposed and optimized with several commercial and cheap refractive index lenses. The probe provides 0.3× magnification and a dispersion range of 400 μm with a commercial LED source with an effective bandwidth of ca. 450–623 nm. Since the noise fluctuation can affect the extraction stability of the focal wavelength, a modification to the centroid peak extraction algorithm is proposed in this paper, where several virtual pixels are interpolated among the real pixels of the spectrometer before thresholding. In addition, a series of experiments were carried out to test the system’s displacement measurement performance. The results clearly show that stability is improved by the modified algorithm, and the calibration repeatability is ±0.3 μm in the full measurement range with a linear stage. The standard deviation at the fixed position has an optimal value of 0.009 μm. The section profile of a Fresnel lens is measured by the CCT system to demonstrate its high feasibility and efficiency.

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Modeling the Influence of Oil Film, Position and Orientation Parameters on the Accuracy of a Laser Triangulation Probe

Cited by 7 publications

References 30 publications

Optical Setup for Error Compensation in a Laser Triangulation System

Optical Setup for Error Compensation in a Laser Triangulation System

Repair Method of Data Loss in Weld Surface Defect Detection Based on Light Intensity and 3D Geometry

Chromatic Confocal Displacement Sensor with Optimized Dispersion Probe and Modified Centroid Peak Extraction Algorithm

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