Error analysis and correction for color in laser triangulation measurement

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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“…A compensation method combining the color-error-library method and the least-squares method can reduce the color error to 10%. 38…”

Section: Cog Of Laser Spotmentioning

confidence: 99%

Improved laser measurement using advanced techniques: A review

Liu

Wang

et al. 2021

Micro & Optical Tech Letters

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“…Therefore, this paper mainly studies the point cloud AOI based on LMT. Although the LTM has been relatively mature, data deviation still can occur under special circumstances especially in the condition which is particularly noisy [8][9][10]. To solve this problem, much research has been done on enhancing the ability to adapt to the external interference of the laser measure.…”

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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“…In addition, they have mastered the influence laws of different environmental factors and raised the corresponding compensation methods. When it comes to the physical properties of the measured surface, scholars have deeply probed the effects of color [14], luminance [15] and curvature [16] of the measured surface as well as dip angle of the measurement point [17] on the measurement accuracy of the LDS, and the results they achieved have notably improved the data acquisition accuracy of the LDS in complex surfaces. Through the aforementioned studies, any influence factor can lead to the centroid skewing phenomenon in the spot image, which finally results in the generation of measuring errors.…”

Section: Introductionmentioning

confidence: 99%

A Laser-Based On-Machine Measuring System for Profile Accuracy of Double-Headed Screw Rotor

Dong

Sun

et al. 2019

Sensors

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Great length, large weight and other factors may cause difficulty in measuring the profile accuracy of the double-headed screw rotor. To solve this problem, an on-machine measuring system based on a laser-displacement sensor (LDS) was designed and implemented in this paper by taking an LXK100 four-axis whirlwind milling machine as the carrier. To improve the measurement accuracy of the system, the generalized variable-structural-element morphological method, polynomial interpolation algorithm and ellipse fitting method were first combined to realize the rapid subpixel centroid extraction from a noise-containing spot image, thus improving the data acquisition accuracy of the LDS, and then the hybrid method was experimentally verified. Next, a wavelet threshold function with high-order differentiability and adaptive wavelet coefficient contractility was constructed based on the hyperbolic tangent function, so as to inhibit the disturbance from random errors and preserve real profile information, and this method was simulated and verified. Subsequently, a smoothing algorithm for point cloud data was proposed based on the Lagrange multiplier method to avoid the defect of the piecewise curve-fitting method, that is, function continuity and differentiability could not be satisfied at piecewise points. Finally, the profile accuracy was calculated in real time according to the data reconstruction result and the machining quality was judged. The measurement experiment of the double-headed screw rotor indicates that the proposed on-machine measuring system can complete the profile accuracy measurement for a screw pitch within 39.7 s with measurement accuracy reaching ±8 μm, and the measurement uncertainties of the major axis, minor axis and screw pitch are 0.72 μm, 0.69 μm and 1.24 μm, respectively. Therefore, the measurement accuracy and efficiency are both remarkably improved.

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Error analysis and correction for color in laser triangulation measurement

Cited by 23 publications

References 18 publications

Improved laser measurement using advanced techniques: A review

Improved laser measurement using advanced techniques: A review

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

A Laser-Based On-Machine Measuring System for Profile Accuracy of Double-Headed Screw Rotor

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