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

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1844 ◽  
Author(s):  
Chengxing Wu ◽  
Baijin Chen ◽  
Chunsheng Ye ◽  
Xiaopeng Yan
Keyword(s):  
Incident Angle ◽  
Free Form ◽  
Laser Triangulation ◽  
Oil Film ◽  
Depth Measurement ◽  
Factors Associated ◽  
Position And Orientation ◽  
Orientation Parameters ◽  
Touch Probe ◽  
Topography Data

The laser triangulation probe conveniently obtains surface topography data of a measured target. However, compared to the touch probe, its reliability and accuracy can be negatively affected by various factors associated with the object being measured and the probe itself. In this paper, to identify potential compensation strategies to improve the accuracy of depth measurement for laser triangulation probe, the measuring errors caused by an oil film on the measured surface, and the probe’s position and orientation parameters with respect to the measuring object (including scan depth, incident angle, and azimuth angle), were studied. A theoretical model based on the geometrical optics, and an empirical model from the error evaluations, were established to quantitatively characterize the error influence of oil film and probe’s parameters, respectively. We also investigated the influence pattern of different filtering methods with several comparison experiments. The verification procedures, measuring both a free-form surface (chevron-corrugated plate) and a gauge block covered with an oil film, demonstrate that these models and measurement suggestions are viable methods for predicting theoretical error and can be used as compensation references to improve the accuracy of depth measurement to the laser triangulation probe.

The FDTD Analysis of Near-Field Response for Microgroove Structure With Standing Wave Illumination for the Realization of Coherent Structured Illumination Microscopy

2021 ◽  
Author(s):  
Yizhao Guan ◽  
Hiromasa Kume ◽  
Shotaro Kadoya ◽  
Masaki Michihata ◽  
Satoru Takahashi
Keyword(s):  
Standing Wave ◽  
Incident Angle ◽  
Near Field ◽  
Super Resolution ◽  
Structured Illumination ◽  
Field Phase ◽  
Structured Illumination Microscopy ◽  
Depth Measurement ◽  
Field Response ◽  
Depth Dependency

Abstract Microstructures are widely used in the manufacture of functional surfaces. An optical-based super-resolution, non-invasive method is preferred for the inspection of surfaces with massive microstructures. The Structured Illumination Microscopy (SIM) uses standing-wave illumination to reach optical super-resolution. Recently, coherent SIM is being studied. It can obtain not only the super-resolved intensity distribution but also the phase and amplitude distribution of the sample surface beyond the diffraction limit. By analysis of the phase-depth dependency, the depth measurement for microgroove structures with coherent SIM is expected. FDTD analysis is applied for observing the near-field response of microgroove under the standing-wave illumination. The near-field phase shows depth dependency in this analysis. Moreover, the effects from microgroove width, the incident angle, and the relative position between the standing-wave peak and center of the microgroove are investigated. It is found the near-field phase change can measure depth until 200 nm (aspect ratio 1) with an error of up to 20.4 nm in the case that the microgroove width is smaller than half of the wavelength.

THE FDTD ANALYSIS OF NEAR-FIELD RESPONSE FOR MICROGROOVE STRUCTURE WITH STANDING WAVE ILLUMINATION FOR THE REALIZATION OF COHERENT STRUCTURED ILLUMINATION MICROSCOPY

2021 ◽  
pp. 1-4
Author(s):  
Yizhao Guan ◽  
Hiromasa Kume ◽  
Shotaro Kadoya ◽  
Masaki Michihata ◽  
Satoru Takahashi
Keyword(s):  
Standing Wave ◽  
Incident Angle ◽  
Near Field ◽  
Super Resolution ◽  
Structured Illumination ◽  
Field Phase ◽  
Structured Illumination Microscopy ◽  
Depth Measurement ◽  
Field Response ◽  
Depth Dependency

Abstract Microstructures are widely used in the manufacture of functional surfaces. An optical-based super-resolution, non-invasive method is preferred for the inspection of surfaces with massive microstructures. The Structured Illumination Microscopy (SIM) uses standing-wave illumination to reach optical super-resolution. Recently, coherent SIM is being studied. It can obtain not only the super-resolved intensity distribution but also the phase and amplitude distribution of the sample surface beyond the diffraction limit. By analysis of the phase-depth dependency, the depth measurement for microgroove structures with coherent SIM is expected. FDTD analysis is applied for observing the near-field response of microgroove under the standing-wave illumination. The near-field phase shows depth dependency in this analysis. Moreover, the effects from microgroove width, the incident angle, and the relative position between the standing-wave peak and center of the microgroove are investigated. It is found the near-field phase change can measure depth until 200 nm (aspect ratio 1) with an error of up to 20.4 nm in the case that the microgroove width is smaller than half of the wavelength.

Influence of Seawater Refractive Index on the Precision of Oil Film Thickness Measurement by Differential Laser Triangulation

2015 ◽  
Vol 42 (4) ◽  
pp. 0408004
Author(s):  
耿云飞 Geng Yunfei ◽  
陈曦 Chen Xi ◽  
金文 Jin Wen ◽  
张惠群 Zhang Huiqun ◽  
邬海强 Wu Haiqiang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Film Thickness ◽  
Thickness Measurement ◽  
Laser Triangulation ◽  
Oil Film ◽  
Film Thickness Measurement

Touch probe radius compensation for coordinate measurement using kriging interpolation

1997 ◽  
Vol 211 (1) ◽  
pp. 11-18 ◽  
Author(s):  
J. R. R. Mayer ◽  
Y. A. Mir ◽  
F Trochu ◽  
A Vafaeesefat ◽  
M Balazinski
Keyword(s):  
Computer Aided Design ◽  
Kriging Interpolation ◽  
Free Form ◽  
Probe Radius ◽  
Part Surface ◽  
Probe Radius Compensation ◽  
Normal Vectors ◽  
Radius Compensation ◽  
Free Form Surfaces ◽  
Touch Probe

Obtaining CAD (computer aided design) descriptions of actual parts having complex surfaces is a key part of the process of reverse engineering. This paper is concerned with the estimation of actual surfaces using coordinate measuring machines fitted with a spherically tipped touch probe. In particular, it addresses in detail the problem of probe radius compensation. A general mathematical model, using kriging, is proposed which first generates the initial probe centre surface and then estimates the compensated or part surface. The compensation is achieved using normal vectors to the initial probe centre surface at each measured point to compensate for the probe radius. The method is validated experimentally on known and free-form surfaces.

scholarly journals Measurement of Free-Form Curved Surfaces Using Laser Triangulation

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3527 ◽  
Author(s):  
Zhixu Dong ◽  
Xingwei Sun ◽  
Weijun Liu ◽  
Heran Yang
Keyword(s):  
Data Acquisition ◽  
Polynomial Interpolation ◽  
Image Sensor ◽  
American Petroleum Institute ◽  
Laser Spot ◽  
Free Form ◽  
Laser Triangulation ◽  
Curved Surfaces ◽  
Extraction Algorithm ◽  
The Impact

Laser triangulation (LT) is widely used in many fields due to its good stability, high resolution and fast speed. However, the accuracy in these applications suffers from severe constraints on the data acquisition accuracy of LT. To solve this problem, the optical triangulation principle, the object equation of the optical path relationship and the deviation of the laser spot centroid are applied to deduce a mathematical model. Therefore, the image sensor inclination errors can be quantitatively calculated, and the collected data are compensated in real time. Further, a threshold sub-pixel gray-gravity (GG) extraction algorithm is proposed; the gradient function and Gaussian fit algorithm are used to set thresholds to remove the impact of the spot edge noise area on the center location; and polynomial interpolation is employed to enhance the data density of the traditional GG method, thus improving the data acquisition accuracy of LT. Finally, the above methods are applied to on-machine measurement of the American Petroleum Institute (API) thread and the screw rotor, respectively. The experimental results prove that the proposed method can significantly improve the measurement accuracy of free-form curved surfaces using LT and that the improved laser spot center extraction algorithm is more suitable for free-form curved surfaces with smaller curvature and more uniform curvature changes.

Optimal Path Planning for Helical Gear Profile Inspection with Point Laser Triangulation Probes

2000 ◽  
Vol 123 (1) ◽  
pp. 90-98 ◽  
Author(s):  
Kevin B. Smith ◽  
Yuan F. Zheng
Keyword(s):  
Optimal Path ◽  
Helical Gear ◽  
Laser Triangulation ◽  
Inspection System ◽  
Geometrical Approach ◽  
Helical Gears ◽  
Optimal Path Planning ◽  
Plan Generation ◽  
Orientation Parameters ◽  
Gear Profile

New commercial Point Laser Triangulation (PLT) probes enable Coordinate Measuring Machines (CMMs) to take faster, noncontact, accurate measurements. In this paper, we address how to apply this technology to inspect helical gears. Traditionally, gears are inspected with slow, costly, and dedicated machines. The proposed flexible inspection system with a fast measuring probe can significantly reduce capital equipment costs and inspection times. Integrating PLT probes on CMMs has been limited partly because of the difficulty in generating optimal inspection paths, and partly because of the highly reflective gear surfaces. Complex sensor-to-surface orientation and obstacle-avoidance requirements of these unique probes are the main cause of the difficulty. This paper presents a geometrical approach for obtaining an optimal path plan for helical gear profile inspection with PLT probes. Models for the orientation parameters and the allowable operating regions for the PLT probe are developed. A collision avoidance strategy is also presented. Although this new method was developed and demonstrated while creating an optimal path plan for inspecting helical gears, the developed models and principles can also be applied to optimal inspection plan generation for other parts.

Sign in / Sign up

Export Citation Format

Share Document