A Confocal Surface Measurement System Having Improved Measurement Accuracy for Rough Surfaces and Measurement Speed

2003 ◽  
Vol 15 (3) ◽  
pp. 331-340 ◽  
Author(s):  
Mitsuhiro Ishihara ◽  
Keyword(s):  
Measurement System ◽  
Measurement Accuracy ◽  
Rough Surfaces ◽  
Reconstruction Algorithm ◽  
Surface Measurement ◽  
Object Surface ◽  
Beam Spot ◽  
Improve Accuracy ◽  
Improved Accuracy ◽  
Surface Measurement System

We discuss a confocal surface measurement system having improved accuracy for rough surfaces and speed. To enhance speed, we propose (1) a novel nonscanning confocal microscope, (2) a fast object surface reconstruction algorithm, and (3) an optical focused plane shift mechanism. The system we developed operates at speeds exceeding a million points per second. To improve accuracy for rough surfaces, we propose optical smoothing using confocal beam spot microscanning. Results of experiments confirmed that the system measures rough surfaces nearly as accurately as smooth surfaces.

scholarly journals Performance Analysis of Surface Reconstruction Algorithms in Vertical Scanning Interferometry Based on Coherence Envelope Detection

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 164
Author(s):  
Dongxu Wu ◽  
Fusheng Liang ◽  
Chengwei Kang ◽  
Fengzhou Fang
Keyword(s):  
Surface Reconstruction ◽  
Measurement Accuracy ◽  
Experimental Studies ◽  
Reconstruction Algorithm ◽  
Low Noise ◽  
Surface Measurement ◽  
Reconstruction Algorithms ◽  
Centroid Method ◽  
Envelope Detection ◽  
Vertical Scanning Interferometry

Optical interferometry plays an important role in the topographical surface measurement and characterization in precision/ultra-precision manufacturing. An appropriate surface reconstruction algorithm is essential in obtaining accurate topography information from the digitized interferograms. However, the performance of a surface reconstruction algorithm in interferometric measurements is influenced by environmental disturbances and system noise. This paper presents a comparative analysis of three algorithms commonly used for coherence envelope detection in vertical scanning interferometry, including the centroid method, fast Fourier transform (FFT), and Hilbert transform (HT). Numerical analysis and experimental studies were carried out to evaluate the performance of different envelope detection algorithms in terms of measurement accuracy, speed, and noise resistance. Step height standards were measured using a developed interferometer and the step profiles were reconstructed by different algorithms. The results show that the centroid method has a higher measurement speed than the FFT and HT methods, but it can only provide acceptable measurement accuracy at a low noise level. The FFT and HT methods outperform the centroid method in terms of noise immunity and measurement accuracy. Even if the FFT and HT methods provide similar measurement accuracy, the HT method has a superior measurement speed compared to the FFT method.

Three dimensional micro surface measurement system based on stereomicroscope

2017 ◽  
Vol 38 (2) ◽  
pp. 607-611
Author(s):  
Li Hui ◽  
Zuo Chao ◽  
Hu Yan ◽  
Zhang Minliang
Keyword(s):  
Measurement System ◽  
Three Dimensional ◽  
Surface Measurement ◽  
Surface Measurement System

Study of camera lens effects for a deflectometry surface measurement system: SCOTS

2014 ◽  
Author(s):  
Run Huang ◽  
Peng Su ◽  
Tianquan Su ◽  
Yuejin Zhao ◽  
Weirui Zhao ◽  
...  
Keyword(s):  
Measurement System ◽  
Surface Measurement ◽  
Camera Lens ◽  
Surface Measurement System

scholarly journals Error Analysis and Compensation of a Laser Measurement System for Simultaneously Measuring Five-Degree-of-Freedom Error Motions of Linear Stages

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3833 ◽  
Author(s):  
Yindi Cai ◽  
Qi Sang ◽  
Zhi-Feng Lou ◽  
Kuang-Chao Fan
Keyword(s):  
Measurement System ◽  
Measurement Accuracy ◽  
Measurement Model ◽  
Degree Of Freedom ◽  
Linear Stage ◽  
Laser Measurement ◽  
Beam Spot ◽  
Error Sources ◽  
Laser Measurement System ◽  
Dual Beam

A robust laser measurement system (LMS), consisting of a sensor head and a detecting part, for simultaneously measuring five-degree-of-freedom (five-DOF) error motions of linear stages, is proposed and characterized. For the purpose of long-travel measurement, all possible error sources that would affect the measurement accuracy are considered. This LMS not only integrates the merits of error compensations for the laser beam drift, beam spot variation, detector sensitivity variation, and non-parallelism of dual-beam that have been resolved by the author’s group before, but also eliminates the crosstalk errors among five-DOF error motions in this study. The feasibility and effectiveness of the designed LMS and modified measurement model are experimentally verified using a laboratory-built prototype. The experimental results show that the designed LSM has the capability of simultaneously measuring the five-DOF error motions of a linear stage up to one-meter travel with a linear error accuracy in sub-micrometer and an angular error accuracy in sub-arcsecond after compensation.

A Handheld 3D Surface Measurement System

2021 ◽  
Author(s):  
Abby M. Lindberg ◽  
F. Garrett Reis ◽  
Micah K. Johnson
Keyword(s):  
Measurement System ◽  
Surface Measurement ◽  
3D Surface ◽  
Surface Measurement System
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