Laser Interferometry Hologram Registration for Three-Dimensional Precision Measurements

2006 ◽  
Author(s):  
Z. Huang ◽  
A. J. Shih ◽  
J. Ni
Keyword(s):  
Holographic Interferometry ◽  
Three Dimensional ◽  
Laser Interferometry ◽  
Depth Of Field ◽  
Measurement Technology ◽  
Registration Method ◽  
Dimensional Precision ◽  
Data Registration ◽  
Cross Correlation Analysis ◽  
Laser Holographic Interferometry

Laser holographic interferometry is an advanced precision measurement technology with sub-μm accuracy and large, over 17 mm, depth-of-field. The limitation of current laser holographic interferometry is the limited measurement area, which cannot be larger than the field of view (FOV). A hologram registration method without using targets is developed to overcome this problem. The theory of laser holographic interferometry, including the phase-shifting and multi-wavelength tuning, is described. The cross-correlation analysis is used to find the translation and overlapped regions, which determine the tilt and shift correction for data registration. The proposed method is validated using two examples with different approaches. The first example, a wheel hub, is smaller than the FOV and demonstrates only 0.1 μm discrepancy of the surface flatness between the registered and standard measurements. The second example, an engine combustion deck surface, is larger than the FOV. The registered surface measurements are compared to that of coordinate measurement machine (CMM) with only 2.5% discrepancy of the peak-to-valley flatness. This data registration method enables the sub-μm precision and large depth of field (several centimeters) measurement of large size objects.

Laser Interferometry Hologram Registration for Three-Dimensional Precision Measurements

2006 ◽  
Vol 128 (4) ◽  
pp. 1006-1013 ◽  
Author(s):  
Zhenhua Huang ◽  
Albert J. Shih ◽  
Jun Ni
Keyword(s):  
Holographic Interferometry ◽  
Three Dimensional ◽  
Surface Profile ◽  
Laser Interferometry ◽  
Depth Of Field ◽  
Registration Method ◽  
Dimensional Precision ◽  
Data Registration ◽  
Cross Correlation Analysis ◽  
Laser Holographic Interferometry

A hologram registration method is developed for the laser holographic interferometry measurement of the 3D surface profile of objects which are larger than the field of view (FOV). The theory of laser holographic interferometry, including the phase-shifting and multiwavelength tuning, is described. The hologram registration without using targets is elaborated. The cross-correlation analysis is used to find the translation and overlapped regions, which determine the tilt and shift correction for data registration. The proposed method is validated using two examples with different approaches. The first example, a wheel hub, is smaller than the FOV and demonstrates only 0.1μm discrepancy of the surface flatness between the registered and standard measurements. The second example, an engine combustion deck surface, is larger than the FOV. The registered surface measurements are compared to that of coordinate measurement machine (CMM) with only 2.5% discrepancy of the peak-to-valley flatness. This data registration method enables the sub-μm precision and large depth of field (several centimeters) measurement of large size objects.

scholarly journals Investigation of Nailed Timber Connections Using the Laser Interferometry Method

2018 ◽  
Vol 26 (4) ◽  
pp. 32-38
Author(s):  
Mykola Savytskyi ◽  
Svitlana Shekhorkina ◽  
Alexander Kesariiskyi ◽  
Valeriy Kondrashchenko ◽  
Stanislav Dukát
Keyword(s):  
Holographic Interferometry ◽  
Laser Interferometry ◽  
Element Model ◽  
Optimum Conditions ◽  
Stress Strain ◽  
Strain Behavior ◽  
Interferometry Method ◽  
Timber Connections ◽  
Holographic Interferometry Method ◽  
Laser Holographic Interferometry

Abstract The paper presents an adapted methodology of laser holographic interferometry for an investigation of the stress-strain state of nailed timber connections. During the study the possibility of detecting local deformations in the connection were verified. The optimum conditions for fixing the samples and the loading ranges to ensure an optimal interference pattern were determined. An investigation of the peculiarities of the interaction between the elements and the stress-strain behavior of nailed timber connections was performed. The experimental data obtained on the stress-strain behavior of a nailed timber connection using the laser holographic interferometry method have sufficient repeatability between different series and can also be used as a criterion verification for a finite-element model.

Data Registration Method Based on Three Dimensional Target

2011 ◽  
Vol 103 ◽  
pp. 87-91
Author(s):  
Xiao Ping Lou ◽  
Nai Guang Lv ◽  
Peng Sun ◽  
Yi Min Lin
Keyword(s):  
Large Scale ◽  
Vision System ◽  
Three Dimensional ◽  
Optimization Methods ◽  
Free Form ◽  
Registration Method ◽  
Scale Free ◽  
Optical Scanning ◽  
Data Registration ◽  
Processing Steps

Data registration method using special three dimensional target to track the structured light measurement system is discussed. Optical scanning device, tracking target and stereo vision system are integrated together to fulfill profile inspection of large-scale free-form surface objects without extra mark points. System architecture and processing steps are introduced and layout optimization methods of three dimensional target are illustrated. Experimental results are showed to evaluate the validity of the registration method and suggests are given to improve the accuracy of the system.

Computer Assisted Image Reconstruction of Oligomer Structure

1976 ◽  
Vol 34 ◽  
pp. 472-473
Author(s):  
A.M. Jones ◽  
A. Max Fiskin
Keyword(s):  
Three Dimensional ◽  
Depth Of Field ◽  
Computer Assisted ◽  
Projection Data ◽  
Two Dimensional ◽  
Single Particles ◽  
Dimensional Reconstruction ◽  
Computer Assisted Image ◽  
The Fourier Transform ◽  
Space Approach

If the tilt of a specimen can be varied either by the strategy of observing identical particles orientated randomly or by use of a eucentric goniometer stage, three dimensional reconstruction procedures are available (l). If the specimens, such as small protein aggregates, lack periodicity, direct space methods compete favorably in ease of implementation with reconstruction by the Fourier (transform) space approach (2). Regardless of method, reconstruction is possible because useful specimen thicknesses are always much less than the depth of field in an electron microscope. Thus electron images record the amount of stain in columns of the object normal to the recording plates. For single particles, practical considerations dictate that the specimen be tilted precisely about a single axis. In so doing a reconstructed image is achieved serially from two-dimensional sections which in turn are generated by a series of back-to-front lines of projection data.

Cryomicroscopy of crotoxin complex crystals at 400 KV

1989 ◽  
Vol 47 ◽  
pp. 826-827
Author(s):  
Jaap Brink ◽  
Wah Chiu
Keyword(s):  
Signal To Noise Ratio ◽  
3D Structure ◽  
Three Dimensional ◽  
Carbon Films ◽  
Depth Of Field ◽  
Basic Subunit ◽  
Ewald Sphere ◽  
Diffraction Patterns ◽  
Complex Crystals ◽  
Acidic Subunit

The crotoxin complex is a potent neurotoxin composed of a basic subunit (Mr = 12,000) and an acidic subunit (M = 10,000). The basic subunit possesses phospholipase activity whereas the acidic subunit shows no enzymatic activity at all. The complex's toxocity is expressed both pre- and post-synaptically. The crotoxin complex forms thin crystals suitable for electron crystallography. The crystals diffract up to 0.16 nm in the microscope, whereas images show reflections out to 0.39 nm2. Ultimate goal in this study is to obtain a three-dimensional (3D-) structure map of the protein around 0.3 nm resolution. Use of 100 keV electrons in this is limited; the unit cell's height c of 25.6 nm causes problems associated with multiple scattering, radiation damage, limited depth of field and a more pronounced Ewald sphere curvature. In general, they lead to projections of the unit cell, which at the desired resolution, cannot be interpreted following the weak-phase approximation. Circumventing this problem is possible through the use of 400 keV electrons. Although the overall contrast is lowered due to a smaller scattering cross-section, the signal-to-noise ratio of especially higher order reflections will improve due to a smaller contribution of inelastic scattering. We report here our preliminary results demonstrating the feasability of the data collection procedure at 400 kV.Crystals of crotoxin complex were prepared on carbon-covered holey-carbon films, quench frozen in liquid ethane, inserted into a Gatan 626 holder, transferred into a JEOL 4000EX electron microscope equipped with a pair of anticontaminators operating at −184°C and examined under low-dose conditions. Selected area electron diffraction patterns (EDP's) and images of the crystals were recorded at 400 kV and −167°C with dose levels of 5 and 9.5 electrons/Å, respectively.

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