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1.
An image registration method based on the Fourier-Mellin transform is introduced for an outdoor augmented reality (AR) system. For this type of AR system, the observation position is fixed, and a complex 3-D registration problem can be reduced to a 2-D image registration for this fixed viewing position system. An observation globe model for this method is proposed. Under this supposition, a Fourier-Mellin transform is used in image registration, and the architecture of this system is illustrated. Experimental results show that this image registration algorithm is accurate and robust. It is effective for an outdoor AR system with a fixed viewing position.  相似文献   

2.
A commonly used lower bound on the probability of error of joint detection and estimation (JDE) algorithms is derived under the assumption that estimation is performed using the transmitted sequence, in a genie-aided fashion. Although it seems reasonable that this genie-aided receiver performs better than the original receiver, a proof of this fact is not available in the literature. In this letter, the validity of this bound is established for a general class of JDE algorithms, as well as for an important special case when the maximum-likelihood sequence detection criterion is used. The results are then extended to a well-known suboptimal JDE algorithm, namely, the T-algorithm. It is shown, however, that the technique used to prove this bound is not sufficient for establishing the validity of the bound for the M-algorithm and the per-survivor processing algorithm.  相似文献   

3.
The Problem of blind signal separation and a simple algorithm is presented. The purpose of this paper is for the introduction to the structure of this problem, and using the simple algorithm to demomstrate the ideas behind the solution of this problem. It is not the intention for a tutorial review of this subject.  相似文献   

4.
In this article, we report a novel method for ultrasensitive high-frequency electron spin resonance (HFESR) using a microcantilever. With this method, a field-gradient force exerting on a sample-holding cantilever is detected as cantilever displacement. A unique feature of this method is that a very tiny sample (~1 µg) is sufficient for HFESR measurement in the terahertz region. Thus, the application of this method to metalloprotein is expected to be of particular interest in the future. In this study, we developed two types of HFESR techniques: one for fiber-optic detection and the other for piezoresistive detection. We applied these techniques to multi-frequency HFESR measurements of metal-containing porphyrin compounds as a model metalloprotein substance and evaluated the sensitivity and feasibility of each technique.  相似文献   

5.
A hardware device for efficiently evaluating the probability of undetected error for a class of CRC error detection codes with a large number of parity check digits is described. The generator polynomial for the codes in this class are of the form g(x)=(1+x)p(x) where p(x) is a primitive irreducible polynomial. The degree of g(x), R, is the number of parity check digits. Using this hardware, a search was conducted for codes in this class (for 8⩽R⩽39) which are “proper” for shortened block lengths. A table of codes satisfying this condition is included  相似文献   

6.
Delta-I noise specification for a high-performance computing machine   总被引:2,自引:0,他引:2  
The design rule formulation for the switching noise containment in a high-performance machine is presented in this paper. This design rule is expressed as an algebraic inequality and condenses the information on the generation and propagation of the switching noise in a multichip carrier to a form that is directly usable for the logic design of a computing machine. The statistics associated with the two quantities essential for the rule derivation, namely, noise generation and noise tolerance, are explained. The methodology necessary for the development of this rule is also described. The experimental procedure used for the verification of this methodology is highlighted.  相似文献   

7.
在大型数据集群网络中,业务逻辑节点和数据库节点分布在不同的地理位置,导致在该网络中创建或检索用户数据将经历较大的网络延迟.如何快速找到用户数据的地理位置节点(服务器识别号)将是减少网络延迟的关键.介绍一种动态索引算法,基于简单正则表达,建立用户数据和服务器组之间的映射关系,并引入动态多叉树,实现动态更改映射关系.引入一元组数据节点和二元组数据节点的概念,应用于多叉树,通过分析一元组多叉树和二元组多叉树的时间效率和空间效率,证明二元组多叉树随着树深的增长,检索时间复杂度保持更好的线性特性.通过一些性能测试的实验数据的比较,得出二元组方案的综合性能更优的结论.最后,简要地介绍该算法的应用领域.  相似文献   

8.
本文简要介绍了分区变分法和Ⅳ族半导体能带的计算,给出了金刚石、硅和锗的能带.在此基础上又讨论了自洽能带计算和经验调整能带计算方法,从而给出了分区变分法的一个完整的概貌.用新的合金能带计算模型计算了锗硅合金的能带,对无序体系电子态的计算进行了一次初步的尝试.最后从计算方法、势场特性和波函数衔接等方面对现有能带计算方法进行了分析和比较,从中看出分区变分法的优点.  相似文献   

9.
In this paper, an adaptive spectral equalization technique is developed for multipath cancellation, and more generally for any minimum-phase distortion, which is implemented by a constrained form of adaptive linear prediction. The technique does not use decisiondirected feedback, has guaranteed convergence and stability, and is simple to realize using conventional circuit technology. Binary amplitude-shift-keying (ASK) is considered as an example of the technique, and the theoretical performance characteristics are derived for a bandlimited pulse shape. Experimental results are also presented for an operational real-time processing system which has been developed for this application and are shown to conform favorably to theory. The analytic and experimental results presented in this paper clearly indicate the usefulness of this concept for a single multipath channel, yielding a performance advantage of between 5 and 20 dB. Particularly significant is the potential of this adaptive technique to acquire and track the multipath without any a priori knowledge of the specific parameters.  相似文献   

10.
Embedded smart camera systems comprise computation- and resource-hungry applications implemented on small, complex but resource-hardy platforms. Efficient implementation of such applications can benefit significantly from parallelization. However, communication between different processing units is a nontrivial task. In addition, new and emerging distributed smart cameras require efficient methods of communication for optimized distributed implementations. In this paper, a novel communication interface, called the signal passing interface (SPI), is presented that attempts to overcome this challenge by integrating relevant properties of two different, yet important, paradigms in this context—dataflow and message passing interface (MPI). Dataflow is a widely used modeling paradigm for signal processing applications, while MPI is an established communication interface in the general-purpose processor community. SPI is targeted toward computation-intensive signal processing applications, and due to its careful specialization, more performance-efficient for embedded implementation in this domain. SPI is also much easier and more intuitive to use. In this paper, successful application of this communication interface to two smart camera applications has been presented in detail to validate a new methodology for efficient distributed implementation for this domain.   相似文献   

11.
In this paper a nonlinear wave metric is introduced for object classification. It is shown that the choice of a metric is a nontrivial problem since it is easy to give examples when well-known distance measures, such as Hamming, Hausdorff, and Nonlinear Hausdorff metrics are completely inadequate for this classification. As an alternative a generalized theorem is proposed that includes the previous metrics as special cases. It is based on nonlinear wave propagation and defines a computational framework that is well-suited for parallel array processors. In this study we investigate different Cellular Neural Network (CNN) architectures and solutions for the proposed metric and analyze its VLSI implementation complexity.  相似文献   

12.
In this paper, a low-frequency square-wave inverter with a series-connected pulsewidth modulation (PWM) inverter is investigated for high-power applications. The series compensators produce only the desired harmonic voltages to make the net output voltage sinusoidal with small PWM switching harmonics only. An open-loop control strategy for the series compensator is proposed in this paper. This strategy indirectly sets the compensator DC bus voltage to the desired level. No external DC source or active power at fundamental frequency is required to control this dc bus voltage. Different variations of this basic strategy are presented in this paper for medium-voltage applications. Theoretical analysis of this strategy is presented in this paper with simulation and experimental results.  相似文献   

13.
一种高安全性的数字图像加密算法   总被引:4,自引:2,他引:4  
提出了一种新的高安全性的数字图像置乱加密算法。该算法变换过程中可以通过密钥进行控制.安全程度仅取决于密钥的长度,避免了Arnold等其它置乱加密算法安全性不高的缺点;该算法变换速度快.几次变换就可以达到很好的置乱效果,在信息隐藏和数宇水印中有很大的实用价值。还给出了一种新的置乱程度的评价标准。  相似文献   

14.
Gamma校正的快速算法及其C语言实现   总被引:1,自引:0,他引:1  
曾嘉亮 《信息技术》2006,30(4):82-85
Gamma校正是数字图像显示前必不可少的操作。若直接套用公式来实现的话,执行效率非常低;许多文献都提到可以使用查找表来加速这一操作,然则语焉不详,并未具体介绍实现方法。在对gamma校正原理进行深入研究的基础上,构造出gamma校正查找表,并提出了运用该表对数字图像进行快速gammaa校正的方法。该算法特别适用于在嵌入式系统中处理视频流。  相似文献   

15.
In this paper it is demonstrated in a wide stress field range that breakdown in thin oxide layers occurs as soon as a critical density of neutral electron traps in the oxide is reached. It is proven that this corresponds to a critical hole fluence, since a unique relationship between electron trap generation and hole fluence is found independent of stress field and oxide thickness. In this way literature models relating breakdown to hole fluence or to trap generation are linked. A new model for intrinsic breakdown, based on a percolation concept, is proposed. It is shown that this model can explain the experimentally observed statistical features of the breakdown distribution, such as the increasing spread of the QBD-distribution for ultrathin oxides. An important consequence of this large spread is the strong area dependence of the QBD for ultrathin oxides  相似文献   

16.
在THz 雷达系统中,接收前端工作频率达百GHz,使得中频信号的“灵敏度”和“选择性”矛盾加剧,两级下变频 结构的接收机能够有效地解决这个问题,第一级下变频选用高的中频有利于提高信号灵敏度、第二级下变频选用较低的 中频则可使信号具有较好的信道选择性。本文基于此应用背景实现了第二级下变频四通道接收单元的模块化设计。测试 结果证明该接收模块具备本振频率可变、基带低通滤波器频率可调、宽动态范围等优良拓展特性,这些特性满足某雷达 系统对第二级下变频单元的要求。本设计验证了THz 雷达系统变频单元模块化设计的可行性,为雷达系统模块化设计提 供了有力的支持。  相似文献   

17.
A large body with cracks and cavities is a typical structure widely existing in realistic targets. In this paper, a newly developed fast and accurate finite-element boundary-integral (FA-FE-BI) method is applied to compute scattering by this kind of scatterer. A thorough analysis on this FA-FE-BI numerical technique is presented, clearly demonstrating that this technique has computational complexity O(N log N) and memory requirement O(N) (N is the total number of surface unknowns). An inward-looking approach is employed as a preconditioner to speed up the rate of convergence of iterative solvers for this structure. Under these techniques, a powerful code is developed for this kind of scatterer whose accuracy, efficiency, and capability is well confirmed by various numerical results.  相似文献   

18.
彭冬亮  吴铁军 《电子学报》2004,32(1):118-120
本文基于单参数变换群理论提出了一种新的自适应滤波器的设计方法,并且给出了滤波器与图象卷积的算法.参数变化后的滤波器的可以表示为事先给定的一组基本滤波器的线性组合.这种滤波器在不同方向、尺度和位置上和图像进行卷积时,可以显著提高运算效率.最后给出了一个图像边缘提取的算例,表明这种方法是有效的.  相似文献   

19.
A new method for the fast evaluation of photoresist residue removal efficiency is discussed in this paper. In this method “haze” which is the low-frequency component of the background signal of a light scattering instrument is mapped over the entire wafer. Since the background signal is sensitive to any kind of surface anomaly, it can be used as a metrology for any kind of surface roughness or residues. The goal of this paper is to devise a fast and cheap screening method for photoresist residue removal efficiency. Using this method we show that cleaning solutions can be easily screened for their residue removal efficiencies based on the haze signal of the light scattering instrument.   相似文献   

20.
It is shown that for an asymmetric multiple-access channel, it is possible, starting with one codeword at each of the encoders, to add the codewords for one message at a time (first for the elements in the set of private messages and thereafter for the messages in the set of common messages) and to construct this way, iteratively, a code for this channel with the average error probability upper-bounded by an exponentially small quantity. Using this result, it is subsequently shown that a code for the asymmetric multiple-access channel can also be generated by only. a few (linear in the block length) permutations, still keeping the average error probability upper-bounded by the same error bound and in this way gaining storage space.  相似文献   

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