Use of Moiré fringes in digital holography for optical alignment

2020 ◽  
Author(s):  
Yihan Liu ◽  
Partha P. Banerjee
Keyword(s):  
Digital Holography ◽  
Moiré Fringes ◽  
Optical Alignment

Moire Fringes on Precipitates in Quenched and Aged Beryllium

1968 ◽  
Vol 26 ◽  
pp. 426-427
Author(s):  
F. J. Fraikor ◽  
A. W. Brewer
Keyword(s):  
Ternary Phase ◽  
Volume Fraction ◽  
Age Hardening ◽  
Orientation Relationships ◽  
Solute Content ◽  
Moiré Fringes ◽  
Moire Patterns ◽  
Total Volume Fraction ◽  
Diffraction Patterns ◽  
Moiré Patterns

A number of investigators have examined moire patterns on precipitate particles in various age-hardening alloys. For example, Phillips has analyzed moire fringes at cobalt precipitates in copper and Von Heimendahl has reported on moire fringes in the system Al-Au. Recently, we have observed moire patterns on impurity precipitates in beryllium quenched in brine from 1000°C and aged at various temperatures in the range of 500-800°C. This heat treatment of beryllium rolled from vacuum cast ingots produces the precipitation of both an fee ternary phase, AlFeBe4, and an hcp binary phase, FeBe11. However, unlike a typical age-hardening alloy, the solute content of this material is low (less than 1000 ppm of Fe and 600 ppm of Al) and hence the total volume fraction of precipitates is small. Therefore there is some difficulty in distinguishing the precipitates and their orientation relationships with the beryllium matrix since the weak precipitate spots generally do not appear on the diffraction patterns.

Digital holography with a set of two close wavelengths for height measurement of solder bumps

2020 ◽  
Vol 59 (SO) ◽  
pp. SOOE03
Author(s):  
Hiroyuki Ishigaki ◽  
Takahiro Mamiya ◽  
Yoshio Hayasaki
Keyword(s):  
Digital Holography ◽  
Height Measurement ◽  
Solder Bumps

Development of 72K Ultra-High-Resolution SLMoG system for high-capacity digital holography image

2019 ◽  
pp. 952
Author(s):  
Jae-Eun Pi ◽  
Ji-Hun Choi ◽  
Jong-Heon Yang ◽  
Chi-Young Hwang ◽  
Gi Heon Kim ◽  
...  
Keyword(s):  
High Resolution ◽  
Digital Holography ◽  
High Capacity

scholarly journals A high-resolution solar spectrum 2000 Å–2200 Å

1970 ◽  
Vol 36 ◽  
pp. 271-273
Author(s):  
B. B. Jones ◽  
B. C. Boland ◽  
R. Wilson ◽  
S. T. F. Engstrom
Keyword(s):  
High Resolution ◽  
Solar Spectrum ◽  
Solar Image ◽  
Roll Control ◽  
North East ◽  
The North ◽  
Alignment System ◽  
Optical Alignment ◽  
South Axis ◽  
System Operating

A high-resolution solar spectrum in the range 2000–2200 Å was obtained in a recent flight of a sunpointing Skylark rocket. This was launched at 04.21 hr UT on April 22, 1969 from Woomera and reached an apogee of 178 km. An optical alignment system operating on the main vehicle pointing system gave a net stabilisation of ±3 arc sec in the position of the solar image relative to the spectrograph slit. The slit, of length 1.0 mm, was set in the north-east quadrant parallel to and 5 arc min from the north/south axis, its lower edge being 1 arc min from the equator. The roll control of ±2.5° was provided entirely by the standard Elliott Bros. type of vehicle stabilisation.

scholarly journals Combined Reduced Phase Dual-Directional Illumination Digital Holography and Speckle Displacements for Shape Measurement

2019 ◽  
Vol 2019 ◽  
pp. 1-6
Author(s):  
Davood Khodadad
Keyword(s):  
Phase Difference ◽  
Digital Holography ◽  
Relative Phase ◽  
Groove Depth ◽  
Phase Unwrapping ◽  
Shape Measurement ◽  
Phase Ambiguity ◽  
Holographic Method ◽  
Height Range ◽  
Phase Differences

We present a digital holographic method to increase height range measurement with a reduced phase ambiguity using a dual-directional illumination. Small changes in the angle of incident illumination introduce phase differences between the recorded complex fields. We decrease relative phase difference between the recorded complex fields 279 and 139 times by changing the angle of incident 0.5° and 1°, respectively. A two cent Euro coin edge groove is used to measure the shape. The groove depth is measured as ≈300  μm. Further, numerical refocusing and analysis of speckle displacements in two different planes are used to measure the depth without a use of phase unwrapping process.

Accurate reconstruction for the measurement of tilt surfaces with digital holography

2021 ◽  
pp. 127135
Author(s):  
He Yuan ◽  
Xiangchao Zhang ◽  
Feili Wang ◽  
Rui Xiong ◽  
Wei Wang ◽  
...  
Keyword(s):  
Digital Holography ◽  
Accurate Reconstruction

Phase map retrieval in digital holography: avoiding the undersampling effect by a lateral shear approach

2007 ◽  
Vol 32 (15) ◽  
pp. 2233 ◽  
Author(s):  
P. Ferraro ◽  
C. Del Core ◽  
L. Miccio ◽  
S. Grilli ◽  
S. De Nicola ◽  
...  
Keyword(s):  
Digital Holography ◽  
Lateral Shear ◽  
Phase Map

Contrast Enhancement in Holographic Moiré Fringes

1983 ◽  
Vol 30 (8) ◽  
pp. 1067-1074 ◽  
Author(s):  
P.K. Rastogi ◽  
P. Jacquot ◽  
L. Pflug
Keyword(s):  
Contrast Enhancement ◽  
Moiré Fringes
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