scholarly journals Simultaneous Measurement of In-Plane and Out-of-Plane Displacements Using Talbot Fringe Projection

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Haibin Sun ◽  
Tingting Liu
Keyword(s):  
Spatial Light Modulator ◽  
Optical Path ◽  
Image Correlation ◽  
Optical Measurements ◽  
Fringe Projection ◽  
Two Dimensional ◽  
Projection Technique ◽  
Light Modulator ◽  
Out Of Plane ◽  
Computer Controlled

The fringe projection technique has been widely used in optical measurements. In this paper, we demonstrate a scheme to measure the 3D displacement of a deformed sample using Talbot fringe projection. In this process, we designed a two-dimensional square Talbot hologram. In this approach, we used the basic principle of triangulation, and a computer-controlled liquid crystal spatial light modulator (LC-SLM) was placed in the optical path. The Talbot array hologram was displayed on the LC-SLM screen and projected onto the surface of a sample. Two patterns were recorded: one before and one after deformation. We simultaneously acquired the in-plane and out-of-plane displacements using the digital image correlation (DIC) method. This scheme is simple and easily implemented. Theoretical and experimental results are presented.

scholarly journals Study of Non-Periodic Pinhole Array Filter for Decreasing High-Order Noise for Compact Holographic Display

2020 ◽  
Vol 10 (23) ◽  
pp. 8671
Author(s):  
Yoo Kwang Kim ◽  
Won Jong Ryu ◽  
Jin Su Lee
Keyword(s):  
Spatial Light Modulator ◽  
Optical Path Length ◽  
Wearable Devices ◽  
Optical Path ◽  
High Order ◽  
Light Modulator ◽  
Noise Sources ◽  
Holographic Display ◽  
Custom Made ◽  
Holographic Displays

The non-periodic pinhole array filtering of a spatial light modulator (SLM) is proposed for filtering the high-order noise and DC noise of a holographic display. Conventionally, DC and high-order noise sources are filtered by a 4f filtering system. Because the 4f filtering system requires a long optical path length, noise filtering is a stumbling block when attempting to realize a compact holographic display. By contrast, the proposed method simply uses a thin filter fabricated by photolithography. In order to verify this concept, we confirmed the feasibility of the filter with a numerical simulation and with a custom-made non-periodic pinhole array filter used in a practical experiment. The proposed method was shown to have the potential to be used in applications ranging from compact wearable devices to table-top holographic displays.

Optical Image Correlation With A Binary Spatial Light Modulator

1984 ◽  
Vol 23 (6) ◽  
Author(s):  
Demetri Psaltis ◽  
Eung G. Paek ◽  
Santosh S. Venkatesh
Keyword(s):  
Spatial Light Modulator ◽  
Optical Image ◽  
Image Correlation ◽  
Light Modulator

Self-correction method of out-of-plane motions in two-dimensional digital image correlation

2016 ◽  
Vol 232 (9) ◽  
pp. 1672-1676 ◽  
Author(s):  
Wentao Yan ◽  
Feng Lin
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Correlation Method ◽  
Correction Method ◽  
Image Correlation ◽  
Two Dimensional ◽  
Monitoring Method ◽  
Strain Monitoring ◽  
Out Of Plane ◽  
Relationship Of

Strain monitoring is very important in the manufacturing, assembling, installation and servicing processes in both mechanical and civil engineering fields. Two-dimensional digital image correlation is a simple, efficient strain monitoring method, but one major bottleneck is the unacceptable error due to the unavoidable out-of-plane motions of the object in practice. We propose a “self-correction” method: employing the originally extracted strain values in different directions to correct the errors due to out-of-plane motions. It is applicable to many engineering applications with known relationship of strains in different directions. A uniaxial tension test was conducted to demonstrate the effectiveness and practicality of this self-correction method. Compared with other correction methods, this method is not only simpler but also more efficient in correcting errors due to the lens distortion caused by self-heating. Both the experiment and theoretical analyses demonstrate that this self-correction method maintains the high accuracy of the digital image correlation method.

Error Assessment of Blade Deformation Measurements on a Multi-Megawatt Wind Turbine Based on Digital Image Correlation

2015 ◽  
Author(s):  
Jan Winstroth ◽  
Joerg R. Seume
Keyword(s):  
Digital Image Correlation ◽  
Wind Turbine ◽  
Error Estimation ◽  
Digital Image ◽  
Rotor Blades ◽  
Image Correlation ◽  
Optical Measurements ◽  
Full Field ◽  
Out Of Plane ◽  
Plane Bending

Optical full-field measurement methods such as Digital Image Correlation (DIC) provide a new opportunity for measuring deformation and vibration in wind turbine rotor blades during operation, in high spatial and temporal resolution. Recent field tests on a multi-megawatt wind turbine have demonstrated the vast potential for full scale testing, however little is known about the overall accuracy of DIC measurements on wind turbines. The present work proposes using a virtual 3D wind turbine model for estimating the error associated with the optical measurements. The entire setup is simulated a priori and accurate error estimation becomes possible. The error estimation for a 3.2 MW wind turbine suggests that relative out-of-plane bending of the rotor blades can be measured with an accuracy of ±9.1 mm, relative in-plane bending of the rotor blades can be measured with an accuracy of ±10.2 mm, and relative blade torsion can be measured with an accuracy of ±0.07 deg. This corresponds to a relative error of 0.46% for out-of-plane bending, 1.11% for in-plane bending and 5.46% for blade torsion.

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