虚拟现实中数据库建模

为了更好地存储和使用虚拟现实中的场景数据,提出了一种用关系数据库方式对虚拟现实中场景数据进行建模的方法．采用该方法,比其他建模方法更加规则地表示了场景数据;提高了三维数据的重用性;增强了对三维场景的可维护性;大大扩展了对特定三维数据的应用;更加合理地存储了二维控制台与虚拟场景交互的数据．该方法也为三维场景数据的优化和格式转化提供了一种途径．     

基于特征地图的改进回环检测算法

为提高移动机器人回环检测模块的准确率和实时性,提出一种基于特征地图的改进回环检测算法。在传 统模型的基础上,对关键帧的特征点进行筛选,选取高效特征点构建特征地图,利用视觉字典树对特征地图和关键 帧进行场景描述;对词袋模型进行改进,将场景分割用在图像信息的提取和特征聚类上;建立基于分层K++均值的 视觉字典树,得到改进的基于分层金字塔TF-IDF(term frequency–inverse document frequency)的匹配方法。实验结果 证明：相比FAB-MAP(fast appearance-based mapping)和RGB-D SLAM v2,改进算法在特征点规模、实时性、召回 率方面性能更优。     

Photoshop脚本工具在金相图片制作上的应用

以景深扩展和视域扩展为例,介绍了Photoshop CS软件的脚本工具在高质量的金相图片制作上的应用实例,这些应用突破了光学金相显微镜和图像采集设备的物理限制,具有智能和高效的特点,可广泛应用在各种类型的金相图片制作中,丰富了金相图片的制作手段,提高了金相分析工作的质量和效率。同时也探讨了图像编辑软件在金相图片制作中的利与弊。     

Forensic Architecture

The urban destruction captured by black and white photos of London after the Blitz or bomb-damaged Berlin are emblematic of the desolation brought by modern warfare. Eyal Weizman , Paulo Tavares , Susan Schuppli and Situ Studio describe, though, how the built environment now represents more than a means of violation in conflict, as it has become an important source of evidence bearing witness to the event when international justice is sought. Copyright © 2010 John Wiley & Sons, Ltd.     

基于深度卷积特征的场景全局与局部表示方法

场景识别是计算机视觉研究中的一项基本任务.与图像分类不同,场景识别需要综合考虑场景的背景信息、局部场景特征以及物体特征等因素,导致经典卷积神经网络在场景识别上性能欠佳.为解决此问题,文中提出了一种基于深度卷积特征的场景全局与局部表示方法.此方法对场景图片的卷积特征进行变换从而为每张图片生成一个综合的特征表示.使用CAM...     

Attention switching during scene perception: How goals influence the time course of eye movements across advertisements.

Eye movements across advertisements express a temporal pattern of bursts of respectively relatively short and long saccades, and this pattern is systematically influenced by activated scene perception goals. This was revealed by a continuous-time hidden Markov model applied to eye movements of 220 participants exposed to 17 ads under a free-viewing condition, and a scene-learning goal (ad memorization), a scene-evaluation goal (ad appreciation), a target-learning goal (product learning), or a target-evaluation goal (product evaluation). The model reflects how attention switches between two states--local and global--expressed in saccades of shorter and longer amplitude on a spatial grid with 48 cells overlaid on the ads. During the 5- to 6-s duration of self-controlled exposure to ads in the magazine context, attention predominantly started in the local state and ended in the global state, and rapidly switched about 5 times between states. The duration of the local attention state was much longer than the duration of the global state. Goals affected the frequency of switching between attention states and the duration of the local, but not of the global, state. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Skeptical Explorer: A Multiple-Hypothesis Approach to Visual Modeling and Exploration

The primary intent of this work is to present a method for sequentially associating three-dimensional surface measurements acquired by an autonomous exploration agent with models that describe those surfaces. Traditional multiple-viewpoint registration approaches are concerned only with finding the transformation that maps data points to a chosen global frame. Given a parts-based object representation, and assuming that the view correspondence can be found, the problem of associating the registered data with the correct part models still needs to be solved. While traditional approaches are content to group segmented data sets that geometrically overlap one another with the same part, there are cases where this causes ambiguous situations. This paper addresses the model-data association problem as it applies to three-dimensional dynamic object modeling. By tracking the state of part models across subsequent views, we wish to identify possible events that explain model-data association ambiguities and represent them in a Bayesian framework. The model-data association problem is therefore relaxed to allow multiple interpretations of the object's structure, each being assigned a probability. Rather than making a decision at every iteration about an ambiguous mapping, we look to the future for the information needed to disambiguate it. Experimental results are presented to illustrate the effectiveness of the approach.     

Do infants segment words or recurring contiguous patterns?

Eight experiments tested the hypothesis that infants' word segmentation abilities are reducible to familiar sound-pattern parsing regardless of actual word boundaries. This hypothesis was disconfirmed. in experiments using the headturn preference procedure: 8.5-month-olds did not mis-segment a consonantvowel- consonant (CVQ word (e.g., dice) from passages containing the corresponding phonemic pattern across a word boundary (C#VC#; "cold ice"), but they segmented it when the word was really present ("roll dice"). However, they did not segment the real vowel-consonant (VC) word (ice in "cold ice") until 16 months. Yet, at that age, they still did not false alarm on the straddling CVC word. Thus, infants do not simply respond to recurring phonemic patterns. Instead, they are sensitive to both acoustic and allophonic cues to word boundaries. Moreover, there is a sizable developmental gap between consonant and vowel-initial word segmentation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Incremental recursive descent parsing

The Recursive Descent method of parsing is well established in practice. An Incremental Parsing algorithm using the Recursive Descent method is presented. The algorithm is applicable to LL(1) grammars. The algorithm has been implemented for a subset of Pascal.     

三维辐射传输模型LESS原理及其应用

三维辐射传输模型能够准确地刻画太阳辐射与异质地表之间的相互作用，近年来已成为定量遥感建模与反演研究中的重要工具。LESS模型是基于光线追踪的三维真实冠层辐射传输模型，充分利用了光线追踪的前向追踪模式模拟能量平衡问题以及后向追踪模式模拟大尺度(公里级)遥感影像，从而实现在同一模型中多种遥感数据的模拟。目前，LESS模型可以模拟多角度反射率、多/高光谱影像、鱼眼相机、复杂地形区上下行短波辐射、冠层分层FPAR等数据，可以为验证物理模型、发展参数化模型以及训练神经网络模型等提供更为可靠的模拟数据集。本文主要介绍了LESS模型的基本原理和典型的应用。LESS模型可以从www.lessrt.org网站下载。