Digital holographic measurement system for high-speed three-dimensional deformation measurements

2010 ◽  
Author(s):  
Christian Kohler ◽  
Matias R. Viotti ◽  
Armando Albertazzi Gonçalves, Jr.
2006 ◽  
Vol 27 (7) ◽  
pp. 1023-1029 ◽  
Author(s):  
Seiichi Nakata ◽  
Yukio Sato ◽  
Pujitha Gunaratne ◽  
Yoshiro Suzuki ◽  
Saiko Sugiura ◽  
...  

Author(s):  
Laura Ekstrand ◽  
Song Zhang

Measuring three-dimensional (3D) surfaces with extremely high contrast (e.g., partially shiny surfaces) is extremely difficult with optical metrology methods. Conventional techniques, which involve measurement from multiple angles or camera aperture adjustments, pose issues for high accuracy measurement in the manufacturing industry because they are difficult to automate and often induce undesirable vibrations in the calibrated measurement system. This paper presents a framework for optically capturing high-contrast 3D surfaces via flexible exposure time variation. This technique leverages the binary defocusing technique that was recently developed at Iowa State University to allow digital fringe projection with a camera exposure time far shorter than the projector’s projection period. Since the camera exposure time can be rapidly adjusted in software, the proposed technique could be automated without mechanical adjustments to the measurement system. Moreover, the exposure times are sufficiently short as to be efficiently packed into a projection period, giving this technique the potential for high speed applications. Experimental results will be presented to demonstrate the success of the proposed method.


2013 ◽  
Vol 365-366 ◽  
pp. 654-657
Author(s):  
Xue Dong Xie ◽  
Wei Ling Zhao

ATOS three-dimensional optical scanner is one of the most advanced technologically three-dimensional optical scanning devices. It can automatically put together the multiple scan view image by the reference point of the measurement system, with high accuracy, high speed Etc. It is widely used in automobiles. The paper combines with the experience in vehicle measurements, analysis the error cause in the actual use, points out ways to reduce or eliminate error. It has the great application value to actual measurement.


2020 ◽  
Vol 29 (07n08) ◽  
pp. 2040014
Author(s):  
Yongchao Wei ◽  
Chunyan Deng ◽  
Xingkun Wu ◽  
Liangzhong Ao

In order to solve the technical problem of three-dimensional profile measurement of aero-engine blades with high speed rotation, an optical dynamic measurement system for aero-engine blades was developed. Firstly, the system is calibrated by the algorithm of spatial truncation phase calibration to establish the index between truncation phase and spatial coordinates. During the measurement, the deformation map of the rotating measured blade is obtained by synchronous projection and snapshot. By using the fast Fourier algorithm, the truncation phase is obtained, and then the profile information of blade can be obtained through the truncation phase and spatial coordinate index. Through the design and construction of the blade simulation platform and dynamic measurement experiment system, the three-dimensional profile data of the blade at different rotating speeds are obtained, compared and analyzed, and then the overall profile deformation law is discovered, which verifies the effectiveness and feasibility of the algorithm. The system can obtain the dynamic profile information of the whole blade completely, and provide innovative technical means for blade design verification and performance analysis.


1996 ◽  
Vol 118 (3) ◽  
pp. 476-481 ◽  
Author(s):  
Jia-Yush Yen ◽  
Chao-Si Jeng ◽  
Kuang-Chau Fan

This paper addresses the servo design for a real-time, laser-tracking, three-dimensional (3-D), position measurement system. The 3-D measurement system uses two sets of tracking mirrors to shine laser beams toward the measurement point. By examining the angles of these mirrors, one can calculate the position of this point. The servo loop in the measurement system corrects the mirror orientations by continuously checking and compensating the offset between the out going laser beam and the beam reflected from a retro-reflector attached to the measurement point. To achieve high speed and high accuracy measurement, the tracking servo system has to compensate for the highly nonlinear nature of the system and maintain the laser beams close to the measurement point. This paper derives the relationship between the tracking angle rotations and the measured beam offsets. By including this relationship in the system model, the linear H∞ optimization technique can be applied for controller synthesis. All the design specifications are then directly implemented.


Author(s):  
Robert W. Mackin

This paper presents two advances towards the automated three-dimensional (3-D) analysis of thick and heavily-overlapped regions in cytological preparations such as cervical/vaginal smears. First, a high speed 3-D brightfield microscope has been developed, allowing the acquisition of image data at speeds approaching 30 optical slices per second. Second, algorithms have been developed to detect and segment nuclei in spite of the extremely high image variability and low contrast typical of such regions. The analysis of such regions is inherently a 3-D problem that cannot be solved reliably with conventional 2-D imaging and image analysis methods.High-Speed 3-D imaging of the specimen is accomplished by moving the specimen axially relative to the objective lens of a standard microscope (Zeiss) at a speed of 30 steps per second, where the stepsize is adjustable from 0.2 - 5μm. The specimen is mounted on a computer-controlled, piezoelectric microstage (Burleigh PZS-100, 68/μm displacement). At each step, an optical slice is acquired using a CCD camera (SONY XC-11/71 IP, Dalsa CA-D1-0256, and CA-D2-0512 have been used) connected to a 4-node array processor system based on the Intel i860 chip.


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