Phase difference-based multichannel phase unwrapping

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.

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Bayesian approach to phase-difference-based phase unwrapping

Conference Record of the Thirty-Sixth Asilomar Conference on Signals Systems and Computers 2002 ACSSC-02 ◽

10.1109/acssc.2002.1197007 ◽

2003 ◽

Cited By ~ 10

Author(s):

G. Fornaro ◽

A. Pauciullo ◽

E. Sansosti

Keyword(s):

Phase Difference ◽

Bayesian Approach ◽

Phase Unwrapping

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RETRACTED: Improved reliability-guided phase unwrapping algorithm based on the fringe modulation and second-order phase difference

Optik ◽

10.1016/j.ijleo.2006.02.004 ◽

2007 ◽

Vol 118 (4) ◽

pp. 175-180 ◽

Cited By ~ 3

Author(s):

Yongjian Zhu ◽

Zhu Luan ◽

Qingguo Yang ◽

Dashan Li ◽

Wei Lu ◽

...

Keyword(s):

Phase Difference ◽

Phase Unwrapping ◽

Second Order ◽

Fringe Modulation

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Phase difference based multiple acquisition phase unwrapping

IGARSS 2003. 2003 IEEE International Geoscience and Remote Sensing Symposium. Proceedings (IEEE Cat. No.03CH37477) ◽

10.1109/igarss.2003.1293973 ◽

2004 ◽

Cited By ~ 8

Author(s):

G. Fornaro ◽

A. Pauciullo ◽

E. Sansosti

Keyword(s):

Phase Difference ◽

Phase Unwrapping ◽

Acquisition Phase

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Surface Crack Search and Marking on Materials with Regional Phase Unwrapping Technology

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.291-294.1074 ◽

2011 ◽

Vol 291-294 ◽

pp. 1074-1081

Author(s):

Yao Ting Zhang ◽

Min Jui Huang

Keyword(s):

Phase Difference ◽

Surface Crack ◽

Threshold Value ◽

Phase Unwrapping ◽

Surface Cracks ◽

Jump Point ◽

Scope Of Application ◽

Phase Map

Depending on the size of sets, a wrapped phase map is unwrapped by either region or pixel. In region phase unwrapping, the jump point threshold value is adjusted to search the region boundary after filtering a wrapped map with higher noise and then phase unwrapping ±2nπ in each region without filtering. The latter compares if the phase difference of adjacent pixels is greater than π as a reference for determining pixel point ±2π to perform phase unwrapping point by point. Although the former unwraps phase by means of boundary search and the latter with the phase difference of adjacent pixels, phase unwrapping errors occur in both cases in detecting surface cracks on materials as data on both sides of a crack are discontinuous. This paper proposes a solution for phase unwrapping on discontinuous surfaces by means of crack search and marking with region assembly phase unwrapping technology to locate boundaries in both region splits and crack splits and further extends the scope of application of region assembly phase unwrapping.

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Measurements of velocity, dimension, and concentration of solid particles in air and in water by phase difference method

International Congress on Applications of Lasers & Electro-Optics ◽

10.2351/1.5057929 ◽

1987 ◽

Cited By ~ 2

Author(s):

C. Alimonti ◽

A. Cenedese ◽

F. Cioffi

Keyword(s):

Phase Difference ◽

Difference Method ◽

Solid Particles

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What Is The Best Distance And Phase Difference Between The Elements Of Linear Antnna Array

10.37376/1570-000-016-009 ◽

2017 ◽

pp. 1

Author(s):

Asma M. N. El Ferjani ◽

Ahmed S. El Barsha ◽

AlZaroog Saleh Abdulali

Keyword(s):

Phase Difference

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Characterization of Flood Waves by Rating Curves

Hydrology Research ◽

10.2166/nh.1997.0004 ◽

1997 ◽

Vol 28 (1) ◽

pp. 51-64 ◽

Cited By ~ 7

Author(s):

S.K. Mishra ◽

M.K. Jain ◽

S.M. Seth

Keyword(s):

Phase Difference ◽

Central India ◽

Wave Number ◽

Wave Characteristics ◽

Travel Wave ◽

Frame Work ◽

Rating Curves ◽

Exact Relationship ◽

Flood Waves

The flood waves are characterized within the frame-work of loop (or hysteresis) of rating curves. The National Weather Service's Dam Break Flood Forecasting Model is used to generate the flood waves in the downstream valley of the Bargi dam located in Central India. The quantified hystereses, η, of non-dimensional rating curves are related with the corresponding flood wave characteristics, viz., speed of travel, wave number, phase difference, and attenuation. The analysis has led to the development of an exact relationship between η and phase difference. Using the concept of wave zoning, the better performance of the hysteresis based criteria compared with the available criteria is verified using Convex and Muskingum-Cunge routing in the wave zones. η limits are specified for the applicability of these simplified routing models. Furthermore, the envisaged applications of the based analysis are introduced.

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