Analogue VLSI primitives for perceptual tasks in machine vision

A variety of computational tasks in early vision can be formulated through lattice networks. The cooperative action of these networks depends upon the topology of interconnections, both feedforward and recurrent ones. The Gabor-like impulse response of a 2nd-order lattice network (i.e. with nearest and next-to-nearest interconnections) is analysed in detail, pointing out how a near-optimal filtering behaviour in space and frequency domains can be achieved through excitatory/inhibitory interactions without impairing the stability of the system. These architectures can be mapped, very efficiently at transistor level, on VLSI structures operating as analogue perceptual engines. The hardware implementation of early vision tasks can, indeed, be tackled by combining these perceptual agents through suitable weighted sums. Various implementation strategies have been pursued with reference to: (i) the algorithm-circuit mapping (current-mode and transconductor approaches); (ii) the degree of programmability (fixed, selectable and tunable); and (iii) the implementation technology (2 and 0.8 gate lengths). Applications of the perceptual engine to machine vision algorithms are discussed.     

Parallel algorithms for image enhancement and segmentation by region growing, with an experimental study

This paper presents efficient and portable implementations of a powerful image enhancement process, the Symmetric Neighborhood Filter (SNF), and an image segmentation technique that makes use of the SNF and a variant of the conventional connected components algorithm which we call -Connected Components. We use efficient techniques for distributing and coalescing data as well as efficient combinations of task and data parallelism. The image segmentation algorithm makes use of an efficient connected components algorithm based on a novel approach for parallel merging. The algorithms have been coded in Split-C and run on a variety of platforms, including the Thinking Machines CM-5, IBM SP-1 and SP-2, Cray Research T3D, Meiko Scientific CS-2, Intel Paragon, and workstation clusters. Our experimental results are consistent with the theoretical analysis (and provide the best known execution times for segmentation, even when compared with machine-specific implementations). Our test data include difficult images from the Landsat Thematic Mapper (TM) satellite data.Also affiliated with the Department of Electrical Engineering.Also affiliated with the Department of Computer Science and the Center for Automation Research.     

WAP网关的研究与实现

WAP网关是WAP应用中的关键部分,是连接移动通信网络和Internet网络的桥梁。本文根据WAP应用大都由Web应用发展而来的现状,设计了一个高性能的WAP网关的架构,对WML编码器进行了设计与实现,并为WAP网关增加了HTML过滤转换器模块,实现了HTML页面到WML页面的翻译转换。     

WSN中改进的IPv6路由查找算法

针对无线传感器网络(WSN)中的全局单播地址,提出一种IPv6快速路由查找机制。利用布鲁姆过滤器作为存储结构,以合适的存储方法降低错误率,采用最长前缀匹配算法合理分配前缀,以减少静态随机存取存储器的数量,降低成本。实验结果表明,利用该算法可以减少每一次查找的散列探头,从而提高路由表的查找速度,改善WSN的性能。     

基于PGF检测的改进彩色图像滤波方法

针对彩色图像中的噪声污染问题,提出一种改进的开关自适应矢量滤波方法。通过对噪声图像进行同组滤波器检测得到滤波窗口内满足检测条件的噪声像素个数,当满足条件的像素个数较少时,直接对检测出的噪声进行矢量中值滤波,当满足条件的像素个数较多时,采用改进的自适应矢量中值滤波器进行2次检测后再滤波。实验结果表明,该方法能提高噪声检测的准确性,并能更好保护滤波的细节。     

改进的Gabor滤波算法在指纹识别中的应用

指纹自动识别系统中图像的处理和匹配算法在系统的设计中起了尤为重要的作用,本文对Gabor滤波算法进行了简化,同时引入了HGF（Half Gabor Filter）对指纹图像进行了增强处理。实验结果表明经过这种改进的Gabor滤波算法提高了图像的处理速度,并很好的保留纹线的关键信息。     

Simulation-based Optimal Design of α-β-γ-δ Filter

The existing third-order tracker known as α-β-γ filter has been used for target tracking and predicting for years. The filter can track the target's position and velocity, but not the acceleration. To extend its capability, a new fourth-order target tracker called α-β-γ-δ filter is proposed. The main objective of this study was to find the optimal set of filter parameters that leads to minimum position tracking errors. The tracking errors between using the α-β-γ filter and the α-β-γ-δ filter are compared. As a result, the new filter exhibits significant improvement in position tracking accuracy over the existing third-order filter, but at the expense of computational time in search of the optimal filter. To reduce the computational time, a simulation-based optimization technique via Taguchi method is introduced.     

基于驱动堆栈单元的文件隐藏方法

为能在操作系统的驱动级实现新的文件隐藏点,对传统的文件系统过滤驱动原理和驱动数据堆栈单元结构进行分析。通过修改驱动堆栈单元的结构和完成例程,配合修改I/O请求包的传递方法,实现2种驱动级文件隐藏的方法。使用该2种方法的文件可以在系统中实现深度隐藏,使得操作系统无法查询,也不能通过正常途径访问。     

Stochastic chaos synchronization using Unscented Kalman-Bucy Filter and sliding mode control

This paper presents an algorithm for synchronizing two different chaotic systems by using a combination of Unscented Kalman-Bucy Filter (UKBF) and sliding mode controller. It is assumed that the drive chaotic system is perturbed by white noise and shows stochastic chaotic behavior. In addition the output of the system does not contain the whole state variables of the system, and it is also affected by some independent white noise. By combining the UKBF and the sliding mode control, a synchronizing control law is proposed. Simulation results show the ability of the proposed method in synchronizing chaotic systems in presence of noise.     

三相并联有源电力滤波器控制策略分析和仿真

该文首先介绍了三相并联型有源电力滤波器的主电路和工作原理,然后分析了基于瞬时无功功率理论的ip—iq电流检测算法并对比研究了滞环比较和三角载波比较两种控制策略,据此建立了仿真模型并进行仿真研究。仿真结果和仿真试验波形验证了该方法的准确性和有效性。