Characterization of aliased fresnel hologram by pixel phase error function

1996 ◽  
Author(s):  
Raimo Silvennoinen
Keyword(s):  
Error Function ◽  
Phase Error ◽  
Fresnel Hologram

Characterization of Fresnel holograms by a pixel phase-error function

1996 ◽  
Vol 21 (7) ◽  
pp. 513 ◽  
Author(s):  
Raimo Silvennoinen ◽  
Jari Räsänen ◽  
Marko Honkanen
Keyword(s):  
Error Function ◽  
Phase Error

Simulation of synthetic Fresnel hologram with pixel phase error function

1996 ◽  
Vol 27 (2) ◽  
pp. 71-79 ◽  
Author(s):  
R Silvennoinen ◽  
J Uozumi ◽  
T Asakura
Keyword(s):  
Error Function ◽  
Phase Error ◽  
Fresnel Hologram

scholarly journals Towards Reduced CNNs for De-Noising Phase Images Corrupted with Speckle Noise

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 255
Author(s):  
Marie Tahon ◽  
Silvio Montresor ◽  
Pascal Picart
Keyword(s):  
Phase Error ◽  
Speckle Noise ◽  
Experimental Conditions ◽  
Benchmark Data ◽  
Wide Range ◽  
Phase Images ◽  
Different Depths ◽  
Phase Data ◽  
Do So

Digital holography is a very efficient technique for 3D imaging and the characterization of changes at the surfaces of objects. However, during the process of holographic interferometry, the reconstructed phase images suffer from speckle noise. In this paper, de-noising is addressed with phase images corrupted with speckle noise. To do so, DnCNN residual networks with different depths were built and trained with various holographic noisy phase data. The possibility of using a network pre-trained on natural images with Gaussian noise is also investigated. All models are evaluated in terms of phase error with HOLODEEP benchmark data and with three unseen images corresponding to different experimental conditions. The best results are obtained using a network with only four convolutional blocks and trained with a wide range of noisy phase patterns.

The Study of Movement Encoder with Low Cost and High Performance

2012 ◽  
Vol 229-231 ◽  
pp. 845-848
Author(s):  
Xiao Wei Wang
Keyword(s):  
Hall Effect ◽  
High Performance ◽  
Low Cost ◽  
Error Function ◽  
Phase Error ◽  
Hall Effect Sensor ◽  
Electric Car ◽  
Position Signal ◽  
Electric Bicycle ◽  
Position Precision

The paper proposes a design scheme of movement encoder with low cost and high performance. The scheme can provide higher precise rotor position signal for motor by a hall-effect latch and a linear hall-effect sensor, and it can also provide rotational speed and direction of motor by a winding with full pole distance, at last we deduce a torque balance equation based on speed and acceleration of motor. The study shows that the scheme with low cost have much higher position precision than traditional rotational transformer and hall-effect position sensor, and it does not exist amplitude error and phase error, function error is small. It is very worthy to the wide application of motor of electric bicycle, wind-driven generator, electric car, and servomotor, etc.

Identifying Elastic Properties of Isotropic Materials by Finite Element Analyses and Vibration Data

2007 ◽  
Vol 345-346 ◽  
pp. 1327-1330 ◽  
Author(s):  
Marco Alfano ◽  
Leonardo Pagnotta ◽  
Giambattista Stigliano
Keyword(s):  
Finite Element ◽  
Error Function ◽  
Finite Element Analyses ◽  
Vibration Testing ◽  
Isotropic Materials ◽  
Vibration Data ◽  
The Difference ◽  
Optimizing Algorithm ◽  
Non Destructive

The use of non destructive techniques for the elastic characterization of isotropic materials is continuously increasing and those based on the modal vibration testing of plate-like specimens is very widespread. In the present paper, an optimized search procedure is proposed which allows the material constants of isotropic plates to be non-destructively identified from vibration testing data and using finite element analyses. The identification process is performed by an optimizing algorithm in which the error function to be minimized depends on the difference between the natural frequencies obtained by finite element analyses and the measured ones. In order to verify the proposed identification procedure a comparison with the results reported in literature has been made.

scholarly journals Sensitivity Analysis of a CPAM Inverse Algorithm for Composite Laminates Characterization

2017 ◽  
Vol 2017 ◽  
pp. 1-14
Author(s):  
Farshid Masoumi ◽  
Ahmad Ghasemi Ghalebahman
Keyword(s):  
Sensitivity Analysis ◽  
Composite Laminates ◽  
Numerical Solutions ◽  
Error Function ◽  
Simulated Data ◽  
Optimization Procedure ◽  
Unknown Parameters ◽  
Finite Element Package

Using experimental data and numerical simulations, a new combined technique is presented for characterization of thin and thick orthotropic composite laminates. Four or five elastic constants, as well as ply orientation angles, are considered as the unknown parameters. The material characterization is first examined for isotropic plates under different boundary conditions to evaluate the method’s accuracy. The proposed algorithm, so-called CPAM (Combined Programs of ABAQUS and MATLAB), utilizes an optimization procedure and makes simultaneous use of vibration test data together with their corresponding numerical solutions. The numerical solutions are based on a commercial finite element package for efficiently identifying the material properties. An inverse method based on particle swarm optimization algorithm is further provided using MATLAB software. The error function to be minimized is the sum of squared differences between experimental and simulated data of eigenfrequencies. To evaluate the robustness of the model’s results in the presence of uncertainty and unwanted noises, a sensitivity analysis that employs Gaussian disorder model is directly applied to the measured frequencies. The results with high accuracy confirm the validity and capability of the present method in simultaneous determination of mechanical constants and fiber orientation angles of composite laminates as compared to prior methods.

scholarly journals Verification of Phase Shifter Measurements of a Reflective Array Antenna

2021 ◽  
Vol 24 (2) ◽  
pp. 18-26
Author(s):  
M. D. Parnes
Keyword(s):  
Measurement Error ◽  
Radiation Pattern ◽  
Antenna Arrays ◽  
Measurement Errors ◽  
Phase Shifter ◽  
Error Function ◽  
Phase Error ◽  
Optical Excitation ◽  
Phase Shifters ◽  
Reference Plane

Introduction.  Large-size phased antenna arrays (PAA) frequently incorporate optical excitation schemes, whose main elements include the feed and the reflective aperture. In turn, the reflective aperture consists of several tens of thousands of radiators and phase shifters. Major distortions of the radiation pattern in reflective arrays occur due to phase errors, leading to a decrease in the gain and an increase in the side lobes of the radiation pattern. In the millimeter wavelength range, ferrite phase shifters can have an initial phase from 0 to 360 °, thus requiring measurements of the array elements following their assembly.Aim.  To develop a method for evaluating errors in measurements of the parameters of phase shifters incorporated in an antenna array by comparing theoretical and experimental data.Materials and methods.  A convenient method for determining the parameters of phase shifters is probing, in which a movable probe is connected in series with each array element. In cases where a PAA element represents a single structure consisting of a ferrite segment and a dielectric radiator, measurements are carried out using a probe in the form of a segment of a round waveguide moving towards the radiator. In order to evaluate the measurement error of such a scheme, a mechanically controlled reference phase shifter was used.Results. Measurement errors for the probe structure used were calculated based on the assumption of the phase error arising from the vector addition of the controlled and uncontrolled reflected signals at the input of the PAA element, in the section of the reference plane at the input of the probe. In addition, the S-parameters of the superposition section were calculated. The extrema of the error function were used to determine the maximum errors in measuring the phase and amplitude.Conclusion. The performed analysis confirmed the validity of the proposed method for measuring the parameters of phase shifters using a waveguide probe. The measurement error of the PAA elements according to the proposed scheme was found to be about 3 o, which is commensurate with that of recording devices.

scholarly journals Pertechnetate/Perrhenate Surface Complexation on Bamboo Engineered Biochar

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 486
Author(s):  
Martin Daňo ◽  
Eva Viglašová ◽  
Karel Štamberg ◽  
Michal Galamboš ◽  
Dušan Galanda
Keyword(s):  
Error Function ◽  
Surface Complexation ◽  
Chemical Properties ◽  
Freundlich Isotherm ◽  
Sorption Data ◽  
Titration Curves ◽  
Similar Chemical ◽  
Complementary Error Function ◽  
Influence Of Ph

The work deals with the evaluation of biochar samples prepared from Phyllostachys Viridiglaucescens bamboo. This evaluation consists of the characterization of prepared materials’ structural properties, batch and dynamic sorption experiments, and potentiometric titrations. The batch technique was focused on obtaining basic sorption data of 99mTcO4− on biochar samples including influence of pH, contact time, and Freundlich isotherm. ReO4−, which has very similar chemical properties to 99mTcO4−, was used as a carrier in the experiments. Theoretical modeling of titration curves of biochar samples was based on the application of surface complexation models, namely, so called Chemical Equilibrium Model (CEM) and Ion Exchange Model (IExM). In this case it is assumed that there are two types of surface groups, namely, the so-called layer and edge sites. The dynamic experimental data of sorption curves were fitted by a model based on complementary error function erfc(x).

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