Group Theoretical Structure of Spectral Spaces

It is known that for every selection of illumination spectra there is a coordinate system such that all coordinate vectors of these illumination spectra are located in a cone. A natural set of transformations of this cone are the Lorentz transformations. In this paper we investigate if sequences of illumination spectra can be described by one-parameter subgroups of Lorentz-transformations. We present two methods to estimate the parameters of such a curve from a set of coordinate points. We also use an optimization technique to approximate a given set of points by a one-parameter curve with a minimum approximation error. In the experimental part of the paper we investigate series of blackbody radiators and sequences of measured daylight spectra and show that one-parameter curves provide good approximations for large sequences of illumination spectra.Reiner Lenz is associate professor at the Department of Science and Technology, Linköping University, Sweden. He held positions as invited researcher at the ZEISS, Germany, the Advanced Telecommunication Research Institute (ATR), Kyoto, Japan, the Mechanical Engineering Laboratory, Tsukuba, Japan, Rutgers University, USA and AIST, Tsukuba, Japan. He received an honorable mention for the Pattern Recognition Society Award and the SAAB-Combitech Award. He is associated editor for Pattern Recognition and the IEEE-Transactions on Image Processing. He is interested in the application of group-theoretical methods in signal-, color-processing.Thanh Hai Bui is currently a Ph.D. student at Media group, Institute of Science and Technology, Linköping University. He obtained his B.Sc. in Computer Science from Hanoi University of Technology in 1995, Post-graduate diploma in Manufacturing System Engineering from Asian Institute of Technology in 1999, Master of Applied Computer Science from Vrije Universiteit Brussel in 2000, and Ph. Licentiate in Media Technology from Linköping Universitet in 2003. His work has mainly focused on multispectral database analysis, and applications of group theoretical methods.Javier Hernández-Andrés received his Ph.D. degree in Physics from the University of Granada, Spain, in 1999. Since 2003 he is an associate professor in the Department of Optics at the same University. His research interests are color-image processing, multispectral color science, applied colorimetry, color vision and atmospheric optics.     

特征库的结构及可视化维护

本文介绍了应用领域的特征库结构、在ＶＰＳＦ系统中如何建立特征库及对特征库进行可视维护，包括增加一个特征到库中、删除库中的特征等。     

Structure Aware Visual Cryptography

Visual cryptography is an encryption technique that hides a secret image by distributing it between some shared images made up of seemingly random black‐and‐white pixels. Extended visual cryptography (EVC) goes further in that the shared images instead represent meaningful binary pictures. The original approach to EVC suffered from low contrast, so later papers considered how to improve the visual quality of the results by enhancing contrast of the shared images. This work further improves the appearance of the shared images by preserving edge structures within them using a framework of dithering followed by a detail recovery operation. We are also careful to suppress noise in smooth areas.     

Visual Analysis of Trajectories in Multi‐Dimensional State Spaces

Multi‐dimensional data originate from many different sources and are relevant for many applications. One specific sub‐type of such data is continuous trajectory data in multi‐dimensional state spaces of complex systems. We adapt the concept of spatially continuous scatterplots and spatially continuous parallel coordinate plots to such trajectory data, leading to continuous‐time scatterplots and continuous‐time parallel coordinates. Together with a temporal heat map representation, we design coordinated views for visual analysis and interactive exploration. We demonstrate the usefulness of our visualization approach for three case studies that cover examples of complex dynamic systems: cyber‐physical systems consisting of heterogeneous sensors and actuators networks (the collection of time‐dependent sensor network data of an exemplary smart home environment), the dynamics of robot arm movement and motion characteristics of humanoids.     

多层结构可视化系统应用服务器的设计与实现

本文设计了一种基于多层结构的可视化系统核心的三层结构,并重点讨论了其应用服务器的设计与实现。应用服务器在系统中专门负责通信的控制,它利用Java的Socket和JNI技术进行前端Web浏览器和后端绘制服务器的通信连接和传输,并实现了多线程机制。实验表明,此系统结构更合理、更利于后期维护和扩展,能最大限度的降低对客户端的软硬件要求。     

多层结构可视化系统应用服务器的设计与实现

本文设计了一种基于多层结构的可视化系统核心的三层结构，并重点讨论了其应用服务器的设计与实现。应用服务器在系统中专门负责通信的控制，它利用Java的Socket和JNI技术进行前端Web浏览器和后端绘制服务器的通信连接和传输。并实现了多线程机制。实验表明，此系统结构更合理、更利于后期维护和扩展，能最大限度的降低对客户端的软硬件要求。     

IT系统结构关系可视化系统

IT系统结构关系可视化系统是一个利用三维可视化技术构建业务至IT设施的可视化管理模型,以立体、仿真、实时互动的方式,呈现系统业务、系统、流程以及支撑的物理设备之间关系的Web系统[1].可以直观的展示不同层次应用节点的业务关系、应用与组件之间所属关系、逻辑组件与物理实体的对应关系、应用业务流向关系、系统监控信息和按条件显示拓扑等,并且支持针对某一节点发生故障的定位及影响分析、故障回溯功能.可视化系统数据来源于配置管理模块、后端使用Struct2+Hibernate4+Spring3技术,前端可视化模块使用Unity3D引擎.整个可视化系统具有使用方便、扩展性好、面向服务、支持配置化、数据呈现直观等特性.     

The Relation Between Field Dependency,Visual Search and Structure of Displays

Abstract

The relation between field dependency and visual search was investigated on displays which differed in terms of the organization of the background elements or structure. Statistically determined displays which differed in the transition probability (p₁,) of the elements from the state ‘ element present’ to ‘ element absent’ were used. A significant correlation between field dependency was found on displays of P, = 0-25 where the elements were clumped, but not on either a regular (P₁ = 1) or a random (P₁ = 0-5) display. A subsidiary finding was a significant effect of transition probability on search times. The practical implications of these results are discussed.

     

具有变结构控制器的无定标视觉伺服*

从控制的角度出发,提出了一种模型无关的无定标视觉伺服控制方法.在该方法中不需要机器人及摄像机模型,图像雅克比矩阵的计算采用最小二乘估计,机器人系统采用变结构的控制理论设计控制器;而后用李亚普诺夫方法对其进行了稳定性分析,结果证明系统能够渐近稳定.仿真实验证明了算法的有效性.     

Discovering Higher Level Structure in Visual SLAM

In this paper, we describe a novel method for discovering and incorporating higher level map structure in a real-time visual simultaneous localization and mapping (SLAM) system. Previous approaches use sparse maps populated by isolated features such as 3-D points or edgelets. Although this facilitates efficient localization, it yields very limited scene representation and ignores the inherent redundancy among features resulting from physical structure in the scene. In this paper, higher level structure, in the form of lines and surfaces, is discovered concurrently with SLAM operation, and then, incorporated into the map in a rigorous manner, attempting to maintain important cross-covariance information and allow consistent update of the feature parameters. This is achieved by using a bottom-up process, in which subsets of low-level features are “folded in” to a parameterization of an associated higher level feature, thus collapsing the state space as well as building structure into the map. We demonstrate and analyze the effects of the approach for the cases of line and plane discovery, both in simulation and within a real-time system operating with a handheld camera in an office environment.      

可视媒体结构分解技术综述

为了满足目前巨大的可视媒体应用需求,针对可视媒体资源具有的海量、多源、异构的特点,研究高效智能的可视媒体处理技术成为当务之急。笔者重点综述了可视媒体技术中结构分解研究现状,希望通过高精度的结构分解解决编辑处理中的结构问题,从而大幅度提升可视媒体应用的质量和效率。     

基于事件结构的并发程序可视化调试方法

在多核和并发技术得到广泛应用的今天,如何有效地调试并发程序,成为一个重要且亟待解决的研究课题.并发程序的不确定性及其行为的复杂性,使得传统的调试技术难以得到有效的应用;而软件维护场景中错误发现与错误调试过程的分离使得错误重现难以实现,面向缺陷报告的调试需求使得自动的错误定位技术难以应用,加剧了调试的困难.针对软件维护阶段由缺陷报告导向的程序调试场景,提出了可视化的并发程序调试方法.该方法能够根据缺陷报告中的信息对程序进行切片,缩小需要分析的代码范围;通过静态分析构造出程序行为的全局视图,帮助程序员发现隐含的程序执行路径;根据事件结构的语义简化程序行为视图,使得行为模型规模可控;根据图形中的分支,引导用户关注路径中的关键操作,从而更快地发现程序中的缺陷.与动态调试方法相比,该方法能够避免错误重现的代价.借助缺陷报告中的信息以及事件结构模型的特点,该方法能够尽量减少状态爆炸的发生.已开发出的交互式并发程序调试工具原型JESVis Debugger,初步实现了所提出的方法.     

The Role of Structure and Content in Perception of Visual Similarity Between Web Pages

In human–computer interaction, users' perception of visual similarity in interfaces may affect how well they judge the relevance of information, construct appropriate mental models, and effectively interact with computers. This is of interest to both computer science and psychology. A review of the theoretical and applied research in visual similarity reveals both a content-oriented and a structural-oriented approach. The present study seeks to understand the content and structural aspects of visual similarity judgment. Unlike early theoretical studies in psychology, web pages were used as realistic stimulus in an experimental study. Structural and content changes to pairs of web pages were incrementally applied in experimental sessions while participants were judging the similarity of these pairs. The results of the experiment indicated that similarity ratings between two pages correlate negatively with the number of alterations made to the layout of one of the pages. Similarity ratings between two pages also declined when distinctive background colors were applied to one of the pages. The experiment also revealed that text-complete web pages received lower similarity ratings than wire frames of the pages. Pages with readable text received higher similarity ratings than pages with unreadable text. The results of this study will help web designers produce web pages of various similarities that will be consistent with users' judgment and help improve similarity-based web researches.     

面向比特币交易网络的拓扑结构可视探索方法

分析比特币交易网络有助于人们理解交易者在比特币交易中的交易模式.比特币交易网络的匿名性和其巨大的规模使得用户很难在分析前对整个交易网络产生大致的认知.提出了一种基于拓扑结构推荐的比特币交易网络可视分析方法.核心思想是为每个节点生成一个向量化表达,在用户交互的基础上,所提算法即可检测一系列相似的结构.案例分析证明了系统能够支持用户对比特币交易中的交易模式进行探索和分析.     

Predicting Visual Perception of Material Structure in Virtual Environments

One of the most accurate yet still practical representation of material appearance is the Bidirectional Texture Function (BTF). The BTF can be viewed as an extension of Bidirectional Reflectance Distribution Function (BRDF) for additional spatial information that includes local visual effects such as shadowing, interreflection, subsurface‐scattering, etc. However, the shift from BRDF to BTF represents not only a huge leap in respect to the realism of material reproduction, but also related high memory and computational costs stemming from the storage and processing of massive BTF data. In this work, we argue that each opaque material, regardless of its surface structure, can be safely substituted by a BRDF without the introduction of a significant perceptual error when viewed from an appropriate distance. Therefore, we ran a set of psychophysical studies over 25 materials to determine so‐called critical viewing distances, i.e. the minimal distances at which the material spatial structure (texture) cannot be visually discerned. Our analysis determined such typical distances typical for several material categories often used in interior design applications. Furthermore, we propose a combination of computational features that can predict such distances without the need for a psychophysical study. We show that our work can significantly reduce rendering costs in applications that process complex virtual scenes.     

基于重瓣花朵拓扑结构模型算法的可视化研究

针对重瓣花朵结构较为复杂、花瓣排列方式非线性较强、三维模拟效果较差的问题,提出了一种重瓣花朵拓扑结构模型算法。以牡丹作为实例,根据植物学中花瓣排列方式理论,加入随机扰动函数,通过扩展的L系统构建出不同层次的花朵形态模型,采用双三次Bezier曲面来构造花瓣模型,运用基于三角形面片模型的二维纹理贴图方法,可完成任意层次的花朵建模。该方法简单直观,并且真实感效果较好。     

The Classification of Digital Covering Spaces

In this paper we classify digital covering spaces using the conjugacy class corresponding to a digital covering space.     

Visual FoxPro中循环语句的解读及应用

针对初学者在循环结构程序设计中存在的问题．分析VisualFoxPro中三种循环语句的区别与联系,并提出采用值列表法阅读有关循环的程序．采用两步法分析问题并灵活应用循环语句编写程序。     

基本型一般访问结构视觉密码的两种算法

视觉密码是一种完善安全的密码体制。近几年,视觉密码学的研究受到广泛关注。本文提出了一般访问结构的两种算法,通过Ateniese-Blundo-Santis-Stinson模型和累计数组的构造方法,对一般访问结构的基本型视觉密码进行讨论,获得了一个一般访问结构的基本型视觉密码方案。