scholarly journals Polarization-Encoded Fully-Phase Encryption Using Transport-of-Intensity Equation

Electronics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 969
Author(s):  
Alok K. Gupta ◽  
Praveen Kumar ◽  
Naveen K. Nishchal ◽  
Ayman Alfalou
Keyword(s):  
Phase Retrieval ◽  
Phase Information ◽  
Intensity Measurements ◽  
Interferometric Phase ◽  
Transport Of Intensity Equation ◽  
Novel Method ◽  
Polarization Encoding ◽  
Set Up ◽  
Spatially Variant ◽  
Information Combining

In this study, we propose a novel method to encrypt fully-phase information combining the concepts of the transport of intensity equation and spatially variant polarization encoding. The transport of intensity equation is a non-iterative and non-interferometric phase-retrieval method which recovers the phase information from defocused intensities. Spatially variant polarization encoding employs defocused intensity measurements. The proposed cryptosystem uses a two-step optical experimentation process—primarily, a simple set-up for defocused intensities recording for phase retrieval and then a set-up for encoding. Strong security, convenient intensity-based measurements, and noise-free decryption are the main features of the proposed method. The simulation results have been presented in support of the proposed idea. However, the TIE section of the cryptosystem, as of now, has been experimentally demonstrated for micro-lens.

Phase Retrieval from Two Defocused Images by the Transport-Ofintensity Equation Formalism with Fast Fourier Transform

2001 ◽  
Vol 7 (S2) ◽  
pp. 430-431
Author(s):  
V.V. Volkov ◽  
Y. Zhu
Keyword(s):  
Phase Retrieval ◽  
Optical Axis ◽  
Fresnel Zone ◽  
Diffraction Tomography ◽  
X Ray ◽  
Intensity Measurements ◽  
Magnetic Inductance ◽  
Experimental Parameters ◽  
Transport Of Intensity Equation ◽  
Made In

The problem of phase retrieval from intensity measurements plays an important role in many fields of physical research, e.g. optics, electron and x-ray microscopy, crystallography, diffraction tomography and others. in practice the recorded images contain information only on the intensity distribution I(x,y) = ψ*ψ*= |A|2 of the imaging wave function ψ = A*exp(-iϕ) and the phase information (ϕ(x,y) is usually lost. in general, the phase problem can be solved either by special holographic/interferometric methods, or by noninterferometric approaches based on intensity measurements in far Fraunhofer zone or in the Fresnel zone at two adjacent planes orthogonal to the optical axis. The latter approach uses the transport-of-intensity equation (TIE) formalism, introduced originally by Teague [1] and developed later in [2]. Applications of TIE to nonmagnetic materials and magnetic inductance mapping were successfully made in [3,4]. However, this approach still needs further improvement both in mathematics and in practical solutions, since the result is very sensitive to many experimental parameters.

scholarly journals Measuring the Phase of an Optical Field from Two Intensity Measurements: Analysis of a Simple Theoretical Model

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Damien P. Kelly
Keyword(s):  
Phase Retrieval ◽  
Complex Function ◽  
Image Plane ◽  
Optical Field ◽  
Optical Systems ◽  
Phase Information ◽  
Fourier Plane ◽  
Optical Elements ◽  
Intensity Measurements ◽  
Theoretical Assumptions

Under the scalar paraxial approximation, an optical wavefield is considered to be complex function dependent on position; i.e., at a given location in space the optical field is a complex value with an intensity and phase. The optical wavefield propagates through space and can be modeled using the Fresnel transform. Lenses, apertures, and other optical elements can be used to control and manipulate the wavefield and to perform different types of signal processing operations. Often these optical systems are described theoretically in terms of linear systems theory leading to a commonly used Fourier optics framework. This is the theoretical framework that we will assume in this manuscript. The problem which we consider is how to recover the phase of an optical wavefield over a plane in space. While today it is relatively straightforward to measure the intensity of the optical wavefield over a plane using CMOS or CCD sensors, recovering the phase information is more complicated. Here we specifically examine a variant of the problem of phase retrieval using two intensity measurements. The intensity of the optical wavefield is recorded in both the image plane and the Fourier plane. To make the analysis simpler, we make a series of important theoretical assumptions and describe how in principle the phase information can be recovered. Then, a deterministic but iterative algorithm is derived and we examine the characteristics and properties of this algorithm. Finally, we examine some of the theoretical assumptions we have made and how valid these assumptions are in practice. We then conclude with a brief discussion of the results.

Multi-phase information aggregation and dynamic synthetic evaluation based on grey inspiriting control lines

2014 ◽  
Vol 4 (2) ◽  
pp. 154-163 ◽  
Author(s):  
San-dang Guo ◽  
Sifeng Liu ◽  
Zhigeng Fang ◽  
Lingling Wang
Keyword(s):  
Future Development ◽  
Information Aggregation ◽  
Development Trend ◽  
Future Application ◽  
Phase Information ◽  
Content Type ◽  
Multi Stage ◽  
Comprehensive Evaluations ◽  
Set Up ◽  
Multi Phase

Purpose – The purpose of this paper is to put forward a multi-stage information aggregation method based on grey inspiriting control lines to evaluate the objects dynamically and comprehensively. Design/methodology/approach – According to the evaluation value of the objects, the positive and negative incentive lines were set up and the predicted values were solved based on the grey GM(1, 1) model, so the value with expected information could be evaluated. In the evaluation, the part above the positive incentive line should be “rewarded” and that below the negative incentive line should be “punished” appropriately. Thereby the double incentive effects of “the current development situation and future development trend” to objects could be implemented on the basis of control. Findings – This method can primarily describe the decision maker's expectancy of the development of evaluation objects and make the evaluation results have better practical application value. Research limitations/implications – Many comprehensive evaluations were always based on the past information. However, the future development trend of the evaluated object is also very important. This study can be used in the evaluation for future application and development. Originality/value – The paper succeeds in providing not only a method of multi-phase information aggregation with expectancy information, but also a simple and convenient method solving nonlinear inspiring lines objectively.

scholarly journals Deceptive Jamming Detection for SAR Based on Cross-Track Interferometry

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2265 ◽  
Author(s):  
Qingqing Feng ◽  
Huaping Xu ◽  
Zhefeng Wu ◽  
Wei Liu
Keyword(s):  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Sar Image ◽  
Frequency Detection ◽  
Interferometric Phase ◽  
Deceptive Jamming ◽  
Jamming Detection ◽  
Novel Method ◽  
The Difference ◽  
Cross Track

Deceptive jamming against synthetic aperture radar (SAR) can create false targets or deceptive scenes in the image effectively. Based on the difference in interferometric phase between the target and deceptive jamming signals, a novel method for detecting deceptive jamming using cross-track interferometry is proposed, where the echoes with deceptive jamming are received by two SAR antennas simultaneously and the false targets are identified through SAR interferometry. Since the derived false phase is close to a constant in interferogram, it is extracted through phase filtering and frequency detection. Finally, the false targets in the SAR image are obtained according to the detected false part in the interferogram. The effectiveness of the proposed method is validated by simulation results based on the TanDEM-X system.

Improvement of Surface Morphology by Solution Flow Control in Solution Growth of SiC on Off-Axis Seeds

2015 ◽  
Vol 821-823 ◽  
pp. 31-34 ◽  
Author(s):  
Tomonori Umezaki ◽  
Daiki Koike ◽  
S. Harada ◽  
Toru Ujihara
Keyword(s):  
Flow Direction ◽  
Seed Crystal ◽  
Solution Growth ◽  
Rotational Axis ◽  
Solution Flow ◽  
Step Flow ◽  
Unidirectional Flow ◽  
Novel Method ◽  
Set Up ◽  
Top Seeded Solution Growth

The solution growth of SiC on an off-axis seed is effective on the reduction of threading dislocations. We proposed a novel method to grow a SiC crystal on an off-axis seed by top-seeded solution growth (TSSG). In our previous study, a unidirectional solution flow above a seed crystal is effective to suppress surface roughness in the growth on the off-axis seed. However, it is difficult to apply the unidirectional flow in an axisymmetric TSSG set-up. In this study, the unidirectional flow could be achieved by shifting the rotational axis away from the center of the seed crystal. As a result, the smooth surface was obtained in the wider area where the solution flow direction was opposite to the step-flow direction.

scholarly journals Handling Fault Diagnosis Problem of Linear-Analogue Circuits with Voltage Phasor Measurement

2014 ◽  
Vol 2014 ◽  
pp. 1-13
Author(s):  
Xin Gao ◽  
HouJun Wang ◽  
Zhen Liu
Keyword(s):  
Fault Diagnosis ◽  
Maximum Error ◽  
Sensitive Test ◽  
Error Evaluation ◽  
Voltage Measurement ◽  
Phase Information ◽  
Analogue Circuit ◽  
Phasor Measurement ◽  
Analogue Circuits ◽  
Novel Method

This paper proposes a novel method to estimate the influence of hard-fault in linear-analogue circuit system based on the measurement of voltage phasor with assistant branch introduced. Furthermore, a new fault diagnosis strategy based on the voltage phasor modeling is established, and the tolerance influence on the corresponding voltage measurement is also discussed. The actual analogue circuit test shows us that the proposed method is effective and reliable to locate the accurate fault signature in voltage measurement for the fault diagnosis. As a matter of fact, it includes both the amplitude and phase information in a complex value form when the linear-analogue circuit is under the AC test. Besides, it can be also applied to ambiguous groups and the sensitive test-frequencies determination in the process of fault diagnosis,while the effectiveness of multifrequencies test has also been testified through test-frequencies sweeping investigation and the maximum error evaluation of fault component value in the second circuit example.

A local search algorithm for plug-and-play reconfiguration of interconnected systems

2016 ◽  
Vol 64 (12) ◽  
Author(s):  
Sven Bodenburg ◽  
Jan Lunze
Keyword(s):  
Search Algorithm ◽  
Interconnected Systems ◽  
Local Algorithm ◽  
Local Search Algorithm ◽  
Plug And Play ◽  
Interconnected System ◽  
Actuator Failures ◽  
Tank System ◽  
Novel Method ◽  
Set Up

AbstractThis paper proposes a novel method to organise the reconfiguration process of decentralised controllers after actuator failures have occurred in an interconnected system. If an actuator fails in a subsystem, only the corresponding control station should be reconfigured, although the fault has effects on other subsystems through the physical couplings. The focus of this paper is on the organisation of the reconfiguration process without a central coordinator. Design agents exist for each of the subsystems which store the subsystem model. A local algorithm is presented to gather models from neighbouring design agents with the aim to set-up a model which describes the behaviour of the faulty subsystem including its neighbours. Furthermore, local reconfiguration conditions are proposed to design a virtual actuator so as to guarantee stability of the overall system. As a consequence, the design agents “play” together to gather the model of the faulty subsystem before the reconfigured control station is “plugged-in” the control hardware. Plug-and-play reconfiguration is illustrated by an interconnected tank system.

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