Three-dimensional intensity and temporal phase measurement of the Airy-Bessel wave packet

2012 ◽  
Author(s):  
Heng Li ◽  
Chenchen Wan ◽  
Andy Chong ◽  
Frank W. Wise
Keyword(s):  
Wave Packet ◽  
Phase Measurement ◽  
Three Dimensional ◽  
Temporal Phase

scholarly journals Transparent Object Shape Measurement Based on Deflectometry

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 548
Author(s):  
Zhichao Hao ◽  
Yuankun Liu
Keyword(s):  
Data Acquisition ◽  
Phase Measurement ◽  
Focal Length ◽  
Three Dimensional ◽  
Normal Direction ◽  
Calibration Data ◽  
Actual Measurement ◽  
Temporal Phase ◽  
Convex Lens ◽  
Normal Orientation

This paper proposes a method for obtaining surface normal orientation and 3-D shape of plano-convex lens using refraction stereo. We show that two viewpoints are sufficient to solve this problem under the condition that the refractive index of the object is known. What we need to know is that (1) an accurate function that maps each pixel to the refraction point caused by the refraction of the object. (2) light is refracted only once. In the simulation, the actual measurement process is simplified: light is refracted only once; and the accurate one-to-one correspondence between incident ray and refractive ray is realized by known object points. The deformed grating caused by refraction point is also constructed in the process of simulation. A plano-convex lens with a focal length of 242.8571 mm is used for stereo data acquisition, normal direction acquisition, and the judgment of normal direction consistency. Finally, restoring the three-dimensional information of the plano-convex lens by computer simulation. Simulation results suggest that our method is feasibility. In the actual experiment, considering the case of light is refracted more than once, combining the calibration data acquisition based on phase measurement, phase-shifting and temporal phase-unwrapping techniques to complete (1) calibrating the corresponding position relationship between the monitor and the camera (2) matching incident ray and refractive ray.

scholarly journals High-Quality Pixel Selection Applied for Natural Scenes in GB-SAR Interferometry

2021 ◽  
Vol 13 (9) ◽  
pp. 1617
Author(s):  
Yunkai Deng ◽  
Weiming Tian ◽  
Ting Xiao ◽  
Cheng Hu ◽  
Hong Yang
Keyword(s):  
Phase Measurement ◽  
High Amplitude ◽  
Sar Interferometry ◽  
Spatial Density ◽  
Natural Scenes ◽  
Sar Images ◽  
High Quality ◽  
Temporal Phase ◽  
Permanent Scatterers ◽  
High Phase

Phase analysis based on high-quality pixel (HQP) is crucial to ensure the measurement accuracy of ground-based SAR (GB-SAR). The amplitude dispersion (ADI) criterion has been widely applied to identify pixels with high amplitude stability, i.e., permanent scatterers (PSs), which typically are point-wise scatterers such as stones or man-made structures. However, the PS number in natural scenes is few and limits the GB-SAR applications. This paper proposes an improved method to take HQP selection applied for natural scenes in GB-SAR interferometry. In order to increase the spatial density of HQP for phase measurement, three types of HQPs including PS, quasi-permanent scatter (QPS), and distributed scatter (DS), are selected with different criteria. The ADI method is firstly utilized to take PS selection. To select those pixels with high phase stability but moderate amplitude stability, the temporal phase coherence (TPC) is defined. Those pixels with moderate ADI values and high TPC are selected as QPSs. Then the feasibility of the DS technique is explored. To validate the feasibility of the proposed method, 2370 GB-SAR images of a natural slope are processed. Experimental results prove that the HQP number could be significantly increased while slightly sacrificing phase quality.

scholarly journals HIDDEN SCALE IN QUANTUM MECHANICS

2009 ◽  
Vol 24 (27) ◽  
pp. 2203-2211 ◽  
Author(s):  
PULAK RANJAN GIRI
Keyword(s):  
Wave Packet ◽  
Quantum Particle ◽  
Dimensional Space ◽  
Free Particle ◽  
Three Dimensional ◽  
Particle Systems ◽  
Quantum Mechanical ◽  
Scale Invariant ◽  
Mechanical Models ◽  
Three Dimensional Space

We show that the intriguing localization of a free particle wave-packet is possible due to a hidden scale present in the system. Self-adjoint extensions (SAE) is responsible for introducing this scale in quantum mechanical models through the nontrivial boundary conditions. We discuss a couple of classically scale invariant free particle systems to illustrate the issue. In this context it has been shown that a free quantum particle moving on a full line may have localized wave-packet around the origin. As a generalization, it has also been shown that particles moving on a portion of a plane or on a portion of a three-dimensional space can have unusual localized wave-packet.

The development of three-dimensional wave-packets in unbounded parallel flows

1968 ◽  
Vol 32 (4) ◽  
pp. 801-808 ◽  
Author(s):  
M. Gaster ◽  
A. Davey
Keyword(s):  
Wave Packet ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Mean Flow ◽  
Physical Plane ◽  
Parallel Flows ◽  
Flow Velocity Profile ◽  
The Stability ◽  
Special Case ◽  
Dimensional Wave

In this paper we examine the stability of a two-dimensional wake profile of the form u(y) = U∞(1 – r e-sy2) with respect to a pulsed disturbance at a point in the fluid. The disturbed flow forms an expanding wave packet which is convected downstream. Far downstream, where asymptotic expansions are valid, the motion at any point in the wave packet is described by a particular three-dimensional wave having complex wave-numbers. In the special case of very unstable flows, where viscosity does not have a significant influence, it is possible to evaluate the three-dimensional eigenvalues in terms of two-dimensional ones using the inviscid form of Squire's transformation. In this way each point in the physical plane can be linked to a particular two-dimensional wave growing in both space and time by simple algebraic expressions which are independent of the mean flow velocity profile. Computed eigenvalues for the wake profile are used in these relations to find the behaviour of the wave packet in the physical plane.

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