行波的小波表示

针对暂态行波故障特征难于表达和提取 ,把小波变换应用于暂态行波故障特征刻划和描述 ,给出了电流行波、电压行波、正向方向行波和反向方向行波故障特征的小波变换模极大值表示 ;并对 4种行波的故障特征进行了初步分析和比较。行波的小波表示客观、全面、简单、明确地反映了不同行波分量的特点 ,为快速检测输电线路故障、构造基于行波原理的故障测距和继电保护奠定了理论基础     

视知觉在建筑造型中的应用

建筑属于视觉感知的艺术,从本质上讲是建筑对象内在关系及其和谐程度的表现形式。本文拟就景观建筑造型、视觉信息传达与人的心理效应间的深层联系进行一些初浅的探索。     

基于人眼视觉系统的运动图像视觉感知模拟

讨论了人眼在观看平板显示屏上运动图像时视觉失真的产生原因,并通过视觉感知实验对已有的视觉感知模型进行了修正,提出了将空间积分的影响加入到视觉感知模型中的改进方法.本文还利用该模型对一些显示屏上运动图像的视觉感知过程进行了模拟,结果表明,采用本文提出的模型获得的运动图像的视觉感知效果图更加接近人眼实际所观测到的图像.本文提出的视觉感知模型以及相关的软件模拟结果为进一步优化显示器件的驱动方法提供了评估手段.     

不同行波方向元件原理与判据的比较

为了研究新型行波方向元件以满足高压输电线路的需要,有必要对现有行波方向元件的本质和相互之间的联系进行深入分析。该文讨论了现有的各种行波方向元件的内在联系,利用方向行波统一了各种行波方向元件的原理以及判据,并给出了各种方向元件在原理和性能上的区别。分析和计算结果表明:各种行波方向元件所依赖的基本物理现象是一样的,它们在本质上是统一的。但是由于各种行波方向元件的判据表达式并不相同,所以它们在性能上仍然存在差异,其中波阻抗方向元件、比率式行波方向元件和幅值比较式行波方向元件具有相对优越的保护性能。     

Involuntary orienting to sound improves visual perception

To perceive real-world objects and events, we need to integrate several stimulus features belonging to different sensory modalities. Although the neural mechanisms and behavioural consequences of intersensory integration have been extensively studied, the processes that enable us to pay attention to multimodal objects are still poorly understood. An important question is whether a stimulus in one sensory modality automatically attracts attention to spatially coincident stimuli that appear subsequently in other modalities, thereby enhancing their perceptual salience. The occurrence of an irrelevant sound does facilitate motor responses to a subsequent light appearing nearby. However, because participants in previous studies made speeded responses rather than psychophysical judgements, it remains unclear whether involuntary auditory attention actually affects the perceptibility of visual stimuli as opposed to postperceptual decision and response processes. Here we provide psychophysical evidence that a sudden sound improves the detectability of a subsequent flash appearing at the same location. These data show that the involuntary orienting of attention to sound enhances early perceptual processing of visual stimuli.     

具边界效应一维粘弹性物质的非凸方程组行波解的稳定性

用权能量方法研究具有边界效应的一维粘弱性物质的非凸方程组解的渐近性质。对非退化的情形，在R 上证明了当时间变量t趋向于无穷时，初边值问题的解收敛于相应的柯西问题的行波解。     

整体拓扑性质的视知觉与计算

提出了一个早期视觉的可能的计算模型，把几何特征分为局部特征与全局特征，认为早期视觉中感知局部几何性质和全局拓扑性质先天运动感知，先于形状感知。模型本质上虽然仍然是读物上，但已不是的传统的ｖｏｎ Ｎｅｕｍａｎｎ的顺序计算，而是非ｖｏｎ Ｎｅｕｍａｎｎ的平行计算，它为计算理论和拓扑性质检测问题之间的矛盾提供了一个可能的解决方法。     

基于行波耦合原理的高压直流输电系统接地极引线故障测距

提出一种基于平行双导线行波耦合原理的接地极引线故障测距方法,推导接地极引线线模波和地模波传播等效参数及耦合规律.该方法建立在接地极引线分布参数模型基础上,采取接地极引线并行线路同时刻注入同极性脉冲的方式,通过脉冲发射和初始线模波时间差计算故障距离.该方法能够消除无故障时脉冲行波在接地极引线上反复传播的不利影响,计算简单,录波量小,定位精度高.仿真结果表明,该方法可以实现高压直流输电系统接地极引线全线范围内故障点的快速、准确测距.     

Preserved figure-ground segregation and symmetry perception in visual neglect.

A central controversy in current research on visual attention is whether figures are segregated from their background preattentively, or whether attention is first directed to unstructured regions of the image. Here we present neurological evidence for the former view from studies of a brain-injured patient with visual neglect. His attentional impairment arises after normal segmentation of the image into figures and background has taken place. Our results indicate that information which is neglected and unavailable to higher levels of visual processing can nevertheless be processed by earlier stages in the visual system concerned with segmentation.     

不受波速影响的输电线路双端行波故障测距算法

提出了一种双端行波故障测距新方法,该方法利用故障初始行波和两种反射行波到达线路两端的时刻来进行故障定位,有效降低了行波波速的不确定和输电线路长度差异对定位结果的不利影响,提高了定位精度.利用EMTP进行了仿真计算,仿真结果证明了其准确性.     

超复数变换域的视感知内容数字水印算法

针对彩色图像内容保护问题,提出一种具有视觉感知属性的超复数频域图像水印嵌入算法.该算法首先用傅氏谱残差方法,在HSI颜色空间提取多分辨率彩色载体图像的归一化显著性区域,再对版权水印混沌置乱加密后,将其嵌入至显著性区域所在的超复数颜色矢量中频段系数中,最终实现对彩色图像显著性内容的盲水印保护.实验表明,该方法能够有效抵抗...     

A computational theory for the perception of coherent visual motion

When we see motion, our perception of how one image feature moves depends on the behaviour of other features nearby. In particular, the Gestaltists proposed the law of shared common fate, in which features tend to be perceived as moving together, that is, coherently. Recent psychophysical findings, such as the cooperativity of the motion system and motion capture, support this law. Computationally, coherence is a sensible assumption, because if two features are close then they probably belong to the same object and thus tend to move together. Moreover, the measurement of local motion may be inaccurate and so the integration of motion information over large areas may help to improve the performance. Present theories of visual motion, however, do not account fully for these coherent motion percepts. We propose here a theory that does account for these phenomena and also provides a solution to the aperture problem, where the local information in the image flow is insufficient to specify the motion uniquely.     

一种基于小波变换的模糊视觉感知水印算法

为了进一步提高目前小波数字水印算法的抗干扰能力,本文提出了一种改进后的小波变换视觉感知模型,设计了一种基于高斯函数的方差和均值的模糊推理规则并将其引入到小波视觉感知模型中,通过上述方法改善了小波视觉感知模型数字水印的抗干扰性能,特别是明显改善了抗压缩攻击的性能。实验结果证明：该算法可进一步提高小波视觉感知数字水印的抗干扰性能,改善其鲁棒性。     

Activation of specific interneurons improves V1 feature selectivity and visual perception

Inhibitory interneurons are essential components of the neural circuits underlying various brain functions. In the neocortex, a large diversity of GABA (γ-aminobutyric acid) interneurons has been identified on the basis of their morphology, molecular markers, biophysical properties and innervation pattern. However, how the activity of each subtype of interneurons contributes to sensory processing remains unclear. Here we show that optogenetic activation of parvalbumin-positive (PV+) interneurons in the mouse primary visual cortex (V1) sharpens neuronal feature selectivity and improves perceptual discrimination. Using multichannel recording with silicon probes and channelrhodopsin-2 (ChR2)-mediated optical activation, we found that increased spiking of PV+ interneurons markedly sharpened orientation tuning and enhanced direction selectivity of nearby neurons. These effects were caused by the activation of inhibitory neurons rather than a decreased spiking of excitatory neurons, as archaerhodopsin-3 (Arch)-mediated optical silencing of calcium/calmodulin-dependent protein kinase IIα (CAMKIIα)-positive excitatory neurons caused no significant change in V1 stimulus selectivity. Moreover, the improved selectivity specifically required PV+ neuron activation, as activating somatostatin or vasointestinal peptide interneurons had no significant effect. Notably, PV+ neuron activation in awake mice caused a significant improvement in their orientation discrimination, mirroring the sharpened V1 orientation tuning. Together, these results provide the first demonstration that visual coding and perception can be improved by increased spiking of a specific subtype of cortical inhibitory interneurons.     

智能车环境视觉感知及其关键技术研究现状

环境视觉感知技术是智能车获取外界环境信息的主要手段,是智能车进行自主驾驶的前提条件。在综合分析以不同检测对象为目标的检测技术方法的基础上,给出了环境视觉感知研究的主要内容,讨论了研究涉及的关键技术:车道检测技术、车辆检测技术、行人检测技术、交通标志检测技术,并对每种检测技术各子技术的优点和不足之处进行了分析。在总结全文的基础上,提出未来智能驾驶中环境视觉感知技术的主要发展趋势包括:基于多特征融合的环境视觉感知技术的发展;复杂环境下多种环境感知技术的融合应用;三维图像在图像处理方面的应用;改进的卷积神经网络(CNN)方法在图像处理方面的应用。     

水果防碰损采摘的视觉认知及其执行机构研究进展

研发水果采摘机器人对提高收获效率、保证果实品质和减轻劳动强度具有重要意义,但由于果园环境的非结构性,使得采摘机器人极易因目标定位不准、采摘顺序不当、夹剪位姿不合理等导致果实碰伤或刮落,造成该损伤的主要原因是防碰损采摘的视觉认知与执行机构耦合问题尚未得到解决。为梳理水果采摘机器人防碰损作业的最新研究进展,从防碰损采摘中果实多维信息（采摘点、果梗位姿、防碰空间包围体等）的视觉感知、采摘机器人的视觉认知与智能防碰损采摘行为规划、防损采摘机构设计及其行为控制等三方面进行了全面综述和分析,并对今后需重点解决的核心关键问题进行总结和展望,为进一步研究和攻克非结构环境下水果智能防碰损采摘问题提供参考和依据。