Analyzing of the Image Characteristic Base on Potential Field Distraction Function

2013 ◽  
Vol 339 ◽  
pp. 389-395
Author(s):  
Ze Biao Shan ◽  
Yao Wu Shi ◽  
Hong Cheng Li ◽  
Hong Wei Shi
Keyword(s):  
Distribution Function ◽  
Field Distribution ◽  
Potential Field ◽  
Transition Point ◽  
Amplitude Distribution ◽  
Threshold Value ◽  
Object Distance ◽  
Image Characteristics ◽  
Image Characteristic ◽  
Definition Of

A new definition of potential field distribution function of image was proposed, and the characteristics of the distribution function were analyzed. Distribution function of potential field represents whole fluctuant information of image. So it can be used to analyze the image characteristics. Potential field of image background is weak and correspond to Gaussian distribution. Low stage of potential field distribution function can be used to evaluate noise level of image. Inflection point of the amplitude distribution function of potential field represented the transition point between the background and the actual edge in potential field image. So value of this point can be used as the threshold value to identify edge. When object distance of microscope changes, the edge comes more and more clear, and the edge area judged by the method above will be bigger and bigger. This character can be used to instruct auto-focus process.

Effect of Imaging Induced by Defilement on Lens

2012 ◽  
Vol 239-240 ◽  
pp. 172-175
Author(s):  
Jian Jun Zhao ◽  
Jin Liu ◽  
Yan Xiong Niu ◽  
Hai Bo Wang ◽  
Shi Yan
Keyword(s):  
Distribution Function ◽  
Field Distribution ◽  
Fourier Transformation ◽  
Light Field ◽  
Image Plane ◽  
Image Theory ◽  
Diffraction Image ◽  
Fraunhofer Diffraction ◽  
Object Distance

An image theory of defiled lens is established in this paper on the basis of Kirchorf theory. By discussion, it was found that light field distribution function of image plane is piled up by image of object and diffracted image of defiled area on lens. It is pointed out that the diffraction image of the defiled lens can be viewed as Fraunhofer diffraction when the object distance is almost infinite, and it can be obtained by Fourier transformation.

scholarly journals On hydrodynamics in the presense of strong external potential field

2021 ◽  
Vol 29 (1) ◽  
pp. 21-28
Author(s):  
A. I. Sokolovsky ◽  
S. A. Sokolovsky
Keyword(s):  
Distribution Function ◽  
Kinetic Equation ◽  
Potential Field ◽  
Chemical Potential ◽  
Local Equilibrium ◽  
Practical Importance ◽  
External Potential ◽  
Equilibrium Distribution Function ◽  
Kinetic Coefficients ◽  
Functional Hypothesis

On the base of the Boltzmann kinetic equation, hydrodynamics of a dilute gas in the presence of the strong external potential field is investigated. First of all, a gravitational field is meant, because the consistent development of hydrodynamics in this environment is of great practical importance. In the present paper it is assumed that it is possible to neglect the influence of the field on the particle collisions. The study is based on the Chapman–Enskog method in a Bogolyubov’s formulation, which uses the idea of the functional hypothesis. Consideration is limited to steady gas states, which are subjected to a simpler experimental study. Chemical potential μ0 of the gas at the point where the external field has zero value and its temperature T are selected as the reduced description parameters of the system. In equilibrium, in the presence of the field, these values do not depend on the coordinates. It is assumed that in thehydrodynamic states T and μ0 are weakly dependent on the coordinates and therefore their gradients, considered on the scale of the free path length of the gas, are small. The kinetic equation, accounting for the functional hypothesis, gives an integro-differential equation for a gas distribution function at the hydrodynamic stage of evolution. This equation is solved in perturbation theory in gradients of T and μ0. The main approximation is analyzed for possibility of the system to be in a local equilibrium by means of comparing it with an equilibrium distribution function. Next, the distribution function is calculated in the first approximation in gradients and it is expressed in terms of solutions Ap , Bp of some first kind integral Fredholm equations. An approach to the approximate solution of these equations is discussed. The found distribution function is used to calculate the fluxes of the number of gas particles and their energy in the first order in gradients T and μ0 . Kinetic coefficients, which describe the structure of these fluxes, are introduced. Matrix elements of the operator of the linearized collision integral (integral brackets) are used for their research. It is a question of validity of the principle of symmetry of kinetic coefficients and definition of their signs.

Defining and Analyzing Forceful Gap Behavior at Unsignalized Intersections

2020 ◽  
Vol 2674 (8) ◽  
pp. 420-428
Author(s):  
Mukti Advani ◽  
Neelam J. Gupta ◽  
S. Velmurugan ◽  
Erramppalli Madhu ◽  
Satish Chandra
Keyword(s):  
Threshold Value ◽  
Base Case ◽  
Major Road ◽  
Speed Reduction ◽  
Critical Gap ◽  
Traffic Conditions ◽  
Unsignalized Intersections ◽  
Definition Of ◽  
Gap Creation ◽  
Made In

Under mixed-mode traffic conditions prevailing on Indian roads at unsignalized intersections, it is commonly observed that vehicles entering from minor streets indulge in forceful gap creation/delay for the vehicles moving on the major road. Although this driving behavior has been reported in some of the published studies for Indian traffic conditions, a clear definition of such forceful entries is not available. An attempt has been made in this study to define this forceful entry phenomenon on the basis of changes in the speed of major streets’ vehicles approaching the intersection on a typical case of mixed-traffic environs. In this regard, field observations were recorded through videography to obtain the speed reduction threshold value for categorizing an entry as a forceful entry. To quantify the above, data in relation to various vehicle types approaching intersections and their associated speeds at the reference area were extracted at the approach arms of the intersection. On the basis of observations, collected data were divided into three scenarios: ( 1 ) vehicles on major roads reduce their speed when vehicles are absent on minor roads; ( 2 ) vehicles on major roads reduce their speed when vehicles are waiting on minor roads; and ( 3 ) vehicles on major roads reduce their speed when vehicles from minor roads have accepted the gap/lag for movement. The changes in speed in all the three scenarios were compared to identify forceful entries with the base case of normal traffic flow on the major road without the existence of forceful entry phenomenon. The study revealed that the speed reduction to the extent of 73% is considered as a forceful entry at the selected location. Furthermore, the study estimated the effect of forceful behavior on critical gap at unsignalized intersections.

scholarly journals Validity of the molecular-dynamics-lattice-gas global equilibrium distribution function

2019 ◽  
Vol 30 (10) ◽  
pp. 1941007 ◽  
Author(s):  
M. Reza Parsa ◽  
Aleksandra Pachalieva ◽  
Alexander J. Wagner
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Lattice Gas ◽  
Equilibrium Distribution ◽  
Coarse Graining ◽  
High Volume ◽  
Equilibrium Distribution Function ◽  
Theory Approach ◽  
Lattice Boltzmann Methods ◽  
Definition Of

The molecular-dynamics-lattice-gas (MDLG) method establishes a direct link between a lattice-gas method and the coarse-graining of a molecular dynamics (MD) approach. Due to its connection to MD, the MDLG rigorously recovers the hydrodynamics and allows to validate the behavior of the lattice-gas or lattice-Boltzmann methods directly without using the standard kinetic theory approach. In this paper, we show that the analytical definition of the equilibrium distribution function remains valid even for very high volume fractions.

scholarly journals Seasonal Variation of Surface Temperature–Modulating Factors in the Sonoran Desert in Northwestern Mexico

2012 ◽  
Vol 51 (8) ◽  
pp. 1519-1530 ◽  
Author(s):  
Iryna Tereshchenko ◽  
Alexander N. Zolotokrylin ◽  
Tatiana B. Titkova ◽  
Luis Brito-Castillo ◽  
Cesar Octavio Monzon
Keyword(s):  
Surface Temperature ◽  
Sonoran Desert ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Threshold Value ◽  
Radiation Mechanism ◽  
Modis Ndvi ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Northwestern Mexico ◽  
Definition Of

AbstractThe authors explore a new approach to monitoring of desertification that is based on use of results on the relation between albedo and surface temperature for the Sonoran Desert in northwestern Mexico. The criteria of predominance of radiation by using the threshold value of Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) were determined. The radiation mechanism for regulating the temperature of the surface and the definition of threshold values for AVHRR and MODIS NDVI have an objective justification for the energy budget, which is based on the dominance of radiation surface temperature regulation in relation to evapotranspiration. Changes in the extent of arid regions with AVHRR NDVI of <0.08 and MODIS NDVI of <0.10 can be considered to be a characteristic in the evolution of desertification in the Sonoran Desert region. This is true because, in a certain year, the time span of the period when radiation factor predominates is important for the desertification process.

scholarly journals Measurement of the Near Field Distribution of a Microwave Horn Using a Resonant Atomic Probe

2019 ◽  
Vol 9 (22) ◽  
pp. 4895 ◽  
Author(s):  
Jingxu Bai ◽  
Jiabei Fan ◽  
Liping Hao ◽  
Nicholas L. R. Spong ◽  
Yuechun Jiao ◽  
...  
Keyword(s):  
Field Distribution ◽  
Electric Fields ◽  
Microwave Field ◽  
Electric Field Distribution ◽  
Near Field ◽  
Field Measurements ◽  
Amplitude Distribution ◽  
Field Coupling ◽  
All Optical ◽  
Atomic Probe

We measure the near field distribution of a microwave horn with a resonant atomic probe. The microwave field emitted by a standard microwave horn is investigated utilizing Rydberg electromagnetically inducted transparency (EIT), an all-optical Rydberg detection, in a room temperature caesium vapor cell. The ground 6 S 1 / 2 , excited 6 P 3 / 2 , and Rydberg 56 D 5 / 2 states constitute a three-level system, used as an atomic probe to detect microwave electric fields by analyzing microwave dressed Autler–Townes (AT) splitting. We present a measurement of the electric field distribution of the microwave horn operating at 3.99 GHz in the near field, coupling the transition 56 D 5 / 2 → 57 P 3 / 2 . The microwave dressed AT spectrum reveals information on both the strength and polarization of the field emitted from the microwave horn simultaneously. The measurements are compared with field measurements obtained using a dipole metal probe, and with simulations of the electromagnetic simulated software (EMSS). The atomic probe measurement is in better agreement with the simulations than the metal probe. The deviation from the simulation of measurements taken with the atomic probe is smaller than the metal probe, improving by 1.6 dB. The symmetry of the amplitude distribution of the measured field is studied by comparing the measurements taken on either side of the field maxima.

scholarly journals SEGMENTING THE EYE FUNDUS IMAGES FOR IDENTIFICATION OF BLOOD VESSELS

2012 ◽  
Vol 17 (1) ◽  
pp. 21-30 ◽  
Author(s):  
Gediminas Balkys ◽  
Gintautas Dzemyda
Keyword(s):  
Blood Vessels ◽  
Binary Classification ◽  
Threshold Value ◽  
Retinal Images ◽  
Fundus Images ◽  
Fundus Image ◽  
Image Characteristics ◽  
Selection For ◽  
Binarization Method ◽  
Local Image

Retinal (eye fundus) images are widely used for diagnostic purposes by ophthalmologists. The normal features of eye fundus images include the optic nerve disc, fovea and blood vessels. Algorithms for identifying blood vessels in the eye fundus image generally fall into two classes: extraction of vessel information and segmentation of vessel pixels. Algorithms of the first group start on known vessel point and trace the vasculature structure in the image. Algorithms of the second group perform a binary classification (vessel or non-vessel, i.e. background) in accordance of some threshold. We focus here on the binarization [4] methods that adapt the threshold value on each pixel to the global/local image characteristics. Global binarization methods [5] try to find a single threshold value for the whole image. Local binarization methods [3] compute thresholds individually for each pixel using information from the local neighborhood of the pixel. In this paper, we modify and improve the Sauvola local binarization method [3] by extending its abilities to be applied for eye fundus pictures analysis. This method has been adopted for automatic detection of blood vessels in retinal images. We suggest automatic parameter selection for Sauvola method. Our modification allows determine/extract the blood vessels almost independently of the brightness of the picture.

Influencing Parameters Analysis of Chloride Threshold Value on Reinforcements Embedded in Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 202-206 ◽  
Author(s):  
Wei Qun Cao ◽  
Xiao Mei Wan ◽  
Tie Jun Zhao
Keyword(s):  
Corrosion Potential ◽  
Threshold Value ◽  
Corrosion Current ◽  
Visual Observation ◽  
Cement Type ◽  
Surface Conditions ◽  
Chloride Threshold ◽  
Type C ◽  
Parameters Analysis ◽  
Definition Of

The chloride threshold to develop active corrosion of the reinforcing steel does not seem to be a unique value and it depends on several factors, such as concrete mix proportions, cement type, C3A content of cement, blended materials, water/cement ratio, temperature, relative humidity, steel surface conditions and source of chloride penetration among others. Numerous studies have been already devoted to the study of the chloride threshold value for depassivation of the steel embedded in concrete. One of the reasons found for the scatter is the large number of variables that influence the chloride amount for depassivation. The other reason is the lack of accordance for the definition of the chloride threshold itself, either on the determining parameters (visual observation, corrosion potential or corrosion current) or on the expression of the threshold (as[Cl-]/[OH-] ratio or by weight of cement or concrete). The present paper presents chloride thresholds expressed as total, free and [Cl-]/[OH-] ratio.

scholarly journals Investigation of Climatological Onset and Withdrawal of the Rainy Season in Panama Based on a Daily Gridded Precipitation Dataset with a High Horizontal Resolution

2015 ◽  
Vol 28 (7) ◽  
pp. 2745-2763 ◽  
Author(s):  
Tosiyuki Nakaegawa ◽  
Osamu Arakawa ◽  
Kenji Kamiguchi
Keyword(s):  
Rainy Season ◽  
Daily Precipitation ◽  
Absolute Threshold ◽  
Threshold Value ◽  
Horizontal Resolution ◽  
Geographical Patterns ◽  
High Horizontal Resolution ◽  
Definition Of ◽  
Surrounding Areas ◽  
Oriented Parallel

Abstract The present study investigated the onset and withdrawal dates of the rainy season in Panama by using newly developed, gridded, daily precipitation datasets with a high horizontal resolution of 0.05° based on ground precipitation observations. The onset and withdrawal dates showed very complicated geographical features, although the country of Panama is oriented parallel to latitude lines, and the geographical patterns of the onset and withdrawal dates could simply reflect the latitudinal migration of the intertropical convergence zone, as seen in other regions and countries. An absolute threshold value of 3 mm day−1 (pentad mean precipitation) was used to determine the onset and withdrawal dates. The onset and withdrawal dates obtained from the gridded daily precipitation dataset clearly depicted the migration of the rainy season. The rainy season starts suddenly in pentad 21 (11–15 April) in most of eastern Panama and in pentad 22 (16–20 April) in most of western Panama. The termination of the rainy season begins in Los Santos Province during pentad 67 (27 November–1 December) and expands to both the eastern and western surrounding areas. There is no dry season in the western part of the Caribbean coastal zone. Water vapor fluxes and topography suggest dynamical causes, such as a topographically induced upward mass flux accompanied by high humidity, for the complicated geographical features of the onset and withdrawal dates. An assessment was made of uncertainties in the timing of the onset and withdrawal associated with the definition of these terms.

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