On the limitation of dual-view triangulation in reducing the measurement error induced by the speckle noise in scanning operations

Ibaraki, Soichi; Kitagawa, Yoshitomo; Kimura, Yoshihiro; Nishikawa, Shizuo

doi:10.1007/s00170-016-8787-x

Cited by 16 publications

(9 citation statements)

References 33 publications

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“…However, these methods are inappropriate for an LTDP because the structures mentioned in these studies have a large volume and are not suitable for a single shot system and there is a dependence on the error or reference signal. Francois Blais [ 11 ] and Soichi Ibaraki [ 18 ] reported a dual-view triangulation method. This structure can suppress the influence of the detected surface, but cannot address the source laser beam directional dithering.…”

Section: Measurement Methodologymentioning

confidence: 99%

Reduction of the Influence of Laser Beam Directional Dithering in a Laser Triangulation Displacement Probe

Yang¹,

Tao²,

Zhang³

et al. 2017

Sensors

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Directional dithering of a laser beam potentially limits the detection accuracy of a laser triangulation displacement probe. A theoretical analysis indicates that the measurement accuracy will linearly decrease as the laser dithering angle increases. To suppress laser dithering, a scheme for reduction of the influence of laser beam directional dithering in a laser triangulation displacement probe, which consists of a collimated red laser, a laser beam pointing control setup, a receiver lens, and a charge-coupled device, is proposed in this paper. The laser beam pointing control setup is inserted into the source laser beam and the measured object and can separate the source laser beam into two symmetrical laser beams. Hence, at the angle at which the source laser beam dithers, the positional averages of the two laser spots are equal and opposite. Moreover, a virtual linear function method is used to maintain a stable average of the positions of the two spots on the imaging side. Experimental results indicate that with laser beam pointing control, the estimated standard deviation of the fitting error decreases from 0.3531 mm to 0.0100 mm, the repeatability accuracy can be lowered from ±7 mm to ±5 sans-serifμnormalm, and the nonlinear error can be reduced from ±6 % FS (full scale) to ±0.16 % FS.

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Section: Measurement Methodologymentioning

confidence: 99%

Reduction of the Influence of Laser Beam Directional Dithering in a Laser Triangulation Displacement Probe

Yang¹,

Tao²,

Zhang³

et al. 2017

Sensors

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show abstract

“…Besides, the movement deflection of the detection probe or the dithering in a dynamic measurement process, for example, a scanning operation will cause a scanning noise. 27 Usually, a symmetrical optical structure can reduce the scanning noise. In 2017, Soichi Ibaraki et al applied a dual-view triangulation with two image sensors symmetrically about the laser beam axis, which reduced the scanning noise by $65%.…”

Section: Light Deflectionmentioning

confidence: 99%

“…Besides, the movement deflection of the detection probe or the dithering in a dynamic measurement process, for example, a scanning operation will cause a scanning noise 27 . Usually, a symmetrical optical structure can reduce the scanning noise.…”

Section: Laser Triangulation Measurementmentioning

confidence: 99%

Improved laser measurement using advanced techniques: A review

Liu

Wang

et al. 2021

Micro & Optical Tech Letters

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Laser measurement technique has been widely explored and applied in various fields in recent years due to its advantages of high measurement precision and resolution. However, applications in frontier fields such as MEMS motion measurement and robotics control pose have requirement for higher precision and resolution, which promote further studies in improving the performance of this technique. Many advanced techniques have been proposed and applied in the laser measurement system to optimize its performance, and the optimized measurement system has found its way in state-of-the-art applications. In this invited paper, we focus on the latest investigations and new applications of the improved laser measurement methods, especially present recent research works regarding the laser triangulation measurement and the laser heterodyne vibration measurement. At the end, we have discussed further developments and challenges of laser measurement technique.

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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%

“…Parameters limiting the accuracy of an LTD can be divided into the laser source [ 15 ], air refractive index [ 5 ], measurement surface [ 16 , 17 ], optomechanical setup [ 18 ], and centroid calculation [ 19 ]. Several techniques were introduced in the past to try to eliminate those limitations or to improve the overall setup.…”

Section: Introductionmentioning

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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On the limitation of dual-view triangulation in reducing the measurement error induced by the speckle noise in scanning operations

Cited by 16 publications

References 33 publications

Reduction of the Influence of Laser Beam Directional Dithering in a Laser Triangulation Displacement Probe

Reduction of the Influence of Laser Beam Directional Dithering in a Laser Triangulation Displacement Probe

Improved laser measurement using advanced techniques: A review

Optical Setup for Error Compensation in a Laser Triangulation System

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