A monocular pose measurement method of a translation-only one-dimensional object without scene information

A monocular method to measure the pose of a translation-only one-dimensional (1D) object containing at least two known characteristic points is presented. The position of any other point on the 1D object can be located after the pose measurement. Scene information is not needed to apply the method. If the distance between the characteristic points is unknown, there is a scale factor between the object's real positions and the measurement results. The method can also be used to measure the pose and shape parameters of a parallelogram, prism or cylinder object.     

A combined approach of Kullback–Leibler divergence and background subtraction for moving object detection in thermal video

In this work, a robust method for moving object detection in thermal video frames has been proposed by including Kullback–Leibler divergence (KLD) based threshold and background subtraction (BGS) technique. A trimmed-mean based background model has been developed that is capable enough to reduce noise or dynamic component of the background. This work assumed that each pixel has normally distributed. The KLD has computed between background pixel and a current pixel with the help of Gaussian mixture model. The proposed threshold is useful enough to classify the state of each pixel. The post-processing step uses morphological tool for edge linking, and then the flood-fill algorithm has applied for hole-filling, and finally the silhouette of targeted object has generated. The proposed methods run faster and have validated over various real-time based problematic thermal video sequences. In the experimental results, the average value of F₁-score, area under the curve, the percentage of correct classification, Matthew’s correlation coefficient show higher values whereas total error and percentage of the wrong classification show minimum values. Moreover, the proposed-1 method achieved higher accuracy and execution speed with minimum false alarm rate that has been compared with proposed-2 as well as considered peer methods in the real-time thermal video.     

Object and Mathematical Simulation of Ammonium Hexafluorosilicate Sublimation

An integration of different modelling methods including object and mathematical simulation are suggested for sublimation processes of inorganic fluorides to optimally simulate the real technological conditions. The paper presents the results of testing this methodology on ammonium hexafluorosilicate sublimation.     

Constructing the Co cyclic Structures for Crossed Copro duct Coalgebras

In this paper, we construct a cocylindrical object associated to two coal-gebras and a cotwisted map. It is shown that there exists an isomorphism between the cocyclic object of the crossed coproduct c...     

聚焦形貌恢复方法模型设计

采用基于拉普拉斯算符聚焦形貌恢复方法,提出了模拟目标深度测量的数值模型。数值模拟的核心是基于通过几何光学预测的理想图像的卷积与透镜广义孔径函数的多色点扩散函数,即用聚焦误差替代抛物线圆柱形貌或高斯函数。该模型可以使用基于聚焦形貌恢复方法的传感器真实组件参数、光源光谱、光学系统离差、相机的光谱灵敏度。提出了光学系统离差（消球差、消色差、色差）对确定目标表面形貌的精确度和可靠性的影响。结果表明,该模型可以有效提高实验效率,缩短时滞,降低成本。     

基于偏振特性对石英玻璃和绿漆涂层的反演

物质的偏振特性与其复折射率、表面粗糙度以及观测几何条件有关,为了应用偏振探测技术实现对目标的定量反演,本文首先对两种典型目标(绿漆涂层和石英玻璃)的偏振特性进行了实验测定,并对偏振度与探测天顶角的关系进行了分析。利用实验数据并基于描述目标偏振特性的PG模型首次在考虑了粗糙度的影响下,对目标的折射率、消光系数进行了定量反演,最后将反演结果与参考结果进行比较。结果表明,石英玻璃的折射率相对误差为4.944 9%,绿漆涂层的折射率与消光系数的相对误差分别为11%和21.558 9%。该方法在考虑表面粗糙度的条件下能够更精确地测定物质的复折射率,同时也为偏振技术应用于目标定量反演提供了依据。     

Coupled Navier–Stokes—Molecular dynamics simulations using a multi‐physics flow simulation framework

Simulation of nano‐scale channel flows using a coupled Navier–Stokes/Molecular Dynamics (MD) method is presented. The flow cases serve as examples of the application of a multi‐physics computational framework put forward in this work. The framework employs a set of (partially) overlapping sub‐domains in which different levels of physical modelling are used to describe the flow. This way, numerical simulations based on the Navier–Stokes equations can be extended to flows in which the continuum and/or Newtonian flow assumptions break down in regions of the domain, by locally increasing the level of detail in the model. Then, the use of multiple levels of physical modelling can reduce the overall computational cost for a given level of fidelity. The present work describes the structure of a parallel computational framework for such simulations, including details of a Navier–Stokes/MD coupling, the convergence behaviour of coupled simulations as well as the parallel implementation. For the cases considered here, micro‐scale MD problems are constructed to provide viscous stresses for the Navier–Stokes equations. The first problem is the planar Poiseuille flow, for which the viscous fluxes on each cell face in the finite‐volume discretization are evaluated using MD. The second example deals with fully developed three‐dimensional channel flow, with molecular level modelling of the shear stresses in a group of cells in the domain corners. An important aspect in using shear stresses evaluated with MD in Navier–Stokes simulations is the scatter in the data due to the sampling of a finite ensemble over a limited interval. In the coupled simulations, this prevents the convergence of the system in terms of the reduction of the norm of the residual vector of the finite‐volume discretization of the macro‐domain. Solutions to this problem are discussed in the present work, along with an analysis of the effect of number of realizations and sample duration. The averaging of the apparent viscosity for each cell face, i.e. the ratio of the shear stress predicted from MD and the imposed velocity gradient, over a number of macro‐scale time steps is shown to be a simple but effective method to reach a good level of convergence of the coupled system. Finally, the parallel efficiency of the developed method is demonstrated. Copyright © 2009 John Wiley & Sons, Ltd.     

Nonlinear optical properties of stimulated Brillouin scattering process in submerged object detection

Nonlinear optical properties of stimulated Brillouin scattering(SBS)to signal detection in water are analyzed.With the threshold characteristics,SBS only occnrs when the high power laser is focused in the SBS cell.When there is an object present in front of the focus,it leads to lower incident intensity and then SBS does not occur.The backward SBS signal depends on the focusing location.The nonlinear optical properties of SBS process in the focusing regime axe analyzed theoretically.With the object coming near to the focusing center,the backward Stokes signal rises up from zero to a maximum,and then grows to saturation.The delay time of the echo signal to pump signal can give the object location.In experiment,the peak position of varying rate of energy can give object location.     

Simple and robust digital holography for high-resolution imaging

Based on the point spread function of holographic system,the lateral resolution of digital holographic imaging system without any pre-magnification is studied.The expression of resolution limitation of holographic imaging system is thus presented.We investigate the possibilities to improve the lateral resolution.The simple experimental setup with an off-axis arrangement is built.By using a U.S.Air Force(USAF)test target as microscopic object,the recorded holograms are reconstructed digitally based on the principle of Fresnel diffraction.The lateral resolution of 2.76 μm without any pre-magnification is demonstrated experimentally,which matches the theoretical prediction well.     

Injective hulls are not natural

In a category with injective hulls and a cogenerator, the embeddings into injective hulls can never form a natural transformation, unless all objects are injective. In particular, assigning to a field its algebraic closure, to a poset or Boolean algebra its Mac-Neille completion, and to an R-module its injective envelope is not functorial, if one wants the respective embeddings to form a natural transformation. Received January 21, 2000; accepted in final form August 10, 2001. RID="h1" RID="h2" RID="h3" ID="h1"The hospitality of York University is gratefully acknowledged by the first author. ID="h2"Third author partially supported by the Grant Agency of the Czech Republic under Grant no. 201/99/0310, and the hospitality of York University is also acknowledged. ID="h3"Partial financial assistance by the Natural Sciences and Engineering Councel of Canada is acknowledged by the fourth author.