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1.
运动模糊是一种常见的图象退化方式。在人们获取图象的过程中,由于物体运动,使得图象的象素并不代表某一点实际灰度,而是一定范围内的相邻象素的灰度值的叠加。当物体的运动模式已知时,这种运动模糊可以用精确的退化算子来描述,从而可以借助于计算机来恢复原始图象。目前,随着图象的恢复算法不断进步,图象恢复技术在许多领域都得到了广泛的应用。在考虑图象存在加性噪声的情况下,目前较成功的恢复算法是正则化图象恢复算法。图象恢复既可以在空域中进行,也可以在频域中进行。本文中所研究的图象恢复是在空域中进行的。1空域图象恢…  相似文献   

2.
一种基于整体变分的图象修补算法   总被引:10,自引:1,他引:10       下载免费PDF全文
图象修补是图象恢复研究中的一个重要内容,它的目的是根据图象现有的信息来自动恢复丢失的信息,可以用于旧照片中丢失信息的恢复。由于图象中的边缘代表了图象的重要信息,所以在设计修补算法时,必须着重考虑边缘的恢复,采用整体变分模型设计了一个图象修补算法,整体变分模型能够模拟人的低层视层,在修补图象时可以恢复图象中的边缘,数值实验表明,该模型能够较好地恢复待修补区域的信息,但是受修补区域大小的影响,同时又采用了一种向前传播操作来缩小修补区域。  相似文献   

3.
基于平均场退火的二值纹理图象恢复   总被引:2,自引:1,他引:1  
汪涛  俞瑞钊 《计算机学报》1994,17(8):618-623
本文根据平均场退火技术,提出了一种二值纹理图象的估计和恢复算法,纹理图象描述为一个马尔可夫随机场模型和噪声过程的综合结果,算法递归地进行模型参数估计和图象恢复,其核心是一个统计松驰搜索算法,平均场方法将统计松驰方程转化为一组确定性方程,从而有效地提高了计算效率,对二值噪声纹理图象的实验结果说明了算法的有效性。  相似文献   

4.
光(电)成像系统的特性会引起图象降质,但如果能够根据系统的传递函数确定其逆滤波函数,就可以对这种降质图象进行一定的恢复.为此,提出了一种用多项式近似的图象逆滤波的图象恢复方法,该方法就是首先将连续的逆滤波函数按泰勒级数展开,并用多项式来近似表示,通过对用多项式表达的用于图象恢复的逆滤波函数作反傅里叶变换,就可得到恢复图象在空间域中的近似运算公式,该运算是图象信号及其各阶导数的线性组合,而不是复杂的反卷积操作.同时还详细分析了方法的原理,并推导了算法公式,最后给出了空移不变和移变系统图象的恢复处理结果.实验表明,该方法特别适合于空间移变系统降质图象的恢复,如场曲恢复.  相似文献   

5.
高斯扩散特性图象的盲解卷积   总被引:3,自引:0,他引:3  
图象的盲解卷积恢复具有重要的理论和实际意义,许多情况下系统的扩散特性不能精确获得。针对一类相对平滑或类似高斯分布的扩散特性,建立一种图象盲解卷积算法,采用交替迭代方法。适合总体最小二乘求解。算法能有效地确定点扩散函数,图象恢复质量有明显改善。最后的仿真实验表明了算法的有效性和稳定性。  相似文献   

6.
一种基于小波变换的迭代正则化图象恢复算法   总被引:6,自引:1,他引:5       下载免费PDF全文
提出一种基于小波变换的迭代正则化图象恢复算法,兼顾抑制噪声的增长和保留图象重要边界。该算法根据图象小波变换各个子频段的不同频率特性和方向特性,分别采用不同的正则化参数和正则化算子。实验结果表明舸用该算法的图象恢复的性能优于常规的空域算法。  相似文献   

7.
在肤色检测、人脸识别、图象和视频检索的研究中,大量算法都是基于对图象色彩特征进行分析的,然而当图象发生偏色时,这些算法的性能会明显下降,甚至无效,而且由于现有的偏色校正算法,引入了其他关于偏色图象的先验性信息,具有很大的使用局限性,为此,提出了一种在只给出偏色图象的条件下,进行偏色检测和自动校正的算法.该算法首先获取并分析偏色图象在RGB各通道内的直方图特征,然后参照这些特征检测偏色通道,并通过调整偏色或非偏色通道强度分布来达到各个通道之间色彩平衡.实验表明,在较大程度的偏色情况下,该算法校正恢复出的图象与原始无偏色图象能达到视觉上基本一致的效果,并具有普遍的适用性.  相似文献   

8.
为了对模糊图象进行高保真度的复原,研究了讨论了一种模糊图象的反扩散恢复算法;该算法首先以图象模糊的尺度为准,在比较为逐次递推算法和传统的单击算法的基础上,给出了它们的适应范围,进而提出了“搜寻-单击”算法,它用逐步逼近方式来探定未知的模糊尺度,然后以尺可能小的累积误差完成反扩散计算,从而实现了模糊图象恢复的盲处理,最后,采用自然模糊与人工模糊的图偈对恢复算法进行了验证,包括算法对模糊尺度的灵敏度算法的有效应用范围,以及纹理结构或景深偏差变化的模糊图象经恢复处理后的效果比较等,试验结果表明对数字图象作为SOS反扩散恢复处理可产生常规光学摄影技术所不可能取得的场景清晰度。  相似文献   

9.
基于动态阈值分块算法的屏幕图象压缩技术   总被引:1,自引:0,他引:1       下载免费PDF全文
计算机屏幕图象压缩一直是屏幕共享技术中的关键问题,而现有算法一般是直接应用传统的RLE,LZW或JPEG算法,但由于这几种算法在对计算机屏幕图象进行压缩时,均无法兼顾恢复质量与压缩比的要求.为此提出了一种基于动态阈值分块的高效压缩算法,该算法首先将屏幕图象按照某种规则划分为纯色块、文字块、图标块和图象块4种特征块,然后针对特征块特点采用相应的压缩算法,以保证压缩算法在恢复质量与压缩比上能同时达到最佳.实验结果表明,该算法图象恢复质量较好,压缩比较大,压缩速度较快,整体性能优于当前现有的屏幕压缩算法,具有广泛的应用前景.  相似文献   

10.
本文提出了一个迭代式的自适应图象恢复算法。它包括一个次优滤波器和两个最小二乘识别器,在此基本结构上结合了迭代方法和活动窗口技术。此算法应用于两张试验图片上,并与其他三种自适应图象恢复算法进行了比较。理论分析与计算结果都证明此算法有较好的图象恢复功能,而且其结构简单,较节省计算时间。  相似文献   

11.
文中介绍了一种系统级故障诊断模型--通用比较模型,该模型处理器作为自身的比较器,综合经典的PMC模型和Maeng/Malek模型的优点,基于该报多处理器系统的t_可诊断性问题,给出了t_可诊断系统的特征化,证明了一个系统成为t-可诊断系统的新的充分必要条件,其次,证明在通用比较模型中,确定故障顺集的问题等价于求解一个超图的最小横切集(Minimum traversal),该超图是根据多处理器的通信  相似文献   

12.
The PEMS high speed maglev train, which features a permanent magnet inside an electromagnet, is a new kind of maglev train for long distance intercity transportation. The joint structure, which consists of two single levitation sub‐systems, is the fundamental levitation unit. Two kinds of faults are considered and corresponding fault tolerant control strategies are proposed. The first fault condition is when a gap sensor that is part of a single levitation system is faulty. For this kind of fault, a fault tolerant control strategy based on signal reconfiguration is proposed. The second fault condition is when the whole of a single levitation sub‐system is faulty. Under this condition, a faulty model is firstly established, then a fault tolerant control strategy is designed. When this kind of fault is detected, a switch from the normal controller to the fault tolerant controller can make the faulty system stable.  相似文献   

13.
在实际应用中有这样一类关系数据库,其中数据项在某个属性上的取值本身又是一个关系。讨论这种混合关系中的函数依赖及其相应的相关规则具有一定的理论意义和实际应用价值。给出这种混合关系的形式定义、混合关系中4种类型的函数依赖关系以及相应的4种类型的相关规则;并给出混合关系到一般关系的转换,通过这个转换说明了混合关系与普通关系的联系及其差别。给出一个实际应用中的例子,来说明混合关系中的函数依赖和相关规则的形式多样性。  相似文献   

14.
The fundamental problem in the design of update strategies for views of database schemata is that of selecting how the view update is to be reflected back to the base schema. This work presents a solution to this problem, based upon the dual philosophies of closed update strategies and order-based database mappings. A closed update strategy is one in which the entire set of updates exhibit natural closure properties, including transitivity and reversibility. The order-based paradigm is a natural one; most database formalisms endow the database states with a natural order structure, under which update by insertion is an increasing operation, and update by deletion is decreasing. Upon augmenting the original constant-complement strategy of Bancilhon and Spyratos – which is an early version of a closed update strategy – with compatible order-based notions, the reflection to the base schema of any update to the view schema which is an insertion, a deletion, or a modification which is realizable as a sequence of insertions and deletions is shown to be unique and independent of the choice of complement. In addition to this uniqueness characterization, the paper also develops a theory which identifies conditions under which a natural, maximal, update strategy exists for a view. This theory is then applied to a ubiquitous example – single-relational schemata constrained by equality-generating dependencies. Within this framework it is shown that for a view defined as a projection of the main relation, the only possibility is that the complement defining the update process is also a projection, and that the reconstruction is based upon functional dependencies.  相似文献   

15.
This paper proposes a distributed self-healing architecture which contains two self-healing techniques. In this proposal, a path restoration by Self-Healing Ring (SHR) and a path restoration by Dynamic Self-Healing (DSH) algorithm are jointly applied in a network. In the architecture, SHR is applied for a part of a path which is terminated by an Add-Drop Multiplexer (ADM), and DSH is applied for another part of a path which is terminated by two Digital Cross-Connect Systems (DCSs). Based on the architecture, DSH can be applied for a part of a path which is terminated by an ADM. Next, a network design algorithm is described in order to optimize the amount of spare capacity. As a result, spare capacity reduction is realized by using the algorithm for a network where the proposed architecture is applied.  相似文献   

16.
In this paper, we study stabilization for a Schoedinger equation, which is interconnected with a heat equation via boundary coupling. A direct boundary feedback control is adopted. By a detailed spectral analysis, it is found that there are two branches of eigenvalues: one is along the negative real axis, and the other is approaching to a vertical line, which is parallel to the imagine axis. Moreover, it is shown that there is a set of generalized eigenfunctions, which forms a Riesz basis for the energy state space. Finally, the spectrum-determined growth condition is held and the exponential stability of the system is then concluded.  相似文献   

17.
Reliable decentralised stabilisation is considered for general multi-channel plants, where the objective is to maintain stability of the closed-loop system when all of decentralised controllers work together and when one of the controllers is extracted due to a failure. For this control problem, a design method is presented, where a dilated LMI technique is employed for deriving reliable state feedback design, while a version of unknown disturbance observer is used as a decentralised observer for extending the design to output feedback case. Applicability of the proposed method is demonstrated through a power system example, where a model reduction and a low pass filter are further employed.  相似文献   

18.
In the paper, a formal model based on Petri nets is proposed in the context of a compositional approach to the development and analysis of complex concurrent and distributed systems. Mutlilabels of Petri nets are introduced allowing labeling a transition not only with a single symbol, but also with a multiset of symbols. Operations on multilabeled Petri nets—parallel composition and restriction—are defined. A definition of a Petri net entity is given based on the notion of multilabels. A Petri net entity is a Petri net with a set of multilabels, where each multilabel is regarded as an access point of the entity. The operation of entity composition is introduced. Equivalence of entities is defined based on bisimulation equivalence of Petri nets. It is shown that the equivalence relation is congruent with respect to entity composition. It is also demonstrated that the composition operation is commutative and associative.  相似文献   

19.
Uncertainty is an attribute of information. The path-breaking work of Shannon has led to a universal acceptance of the thesis that information is statistical in nature. Concomitantly, existing theories of uncertainty are based on probability theory. The generalized theory of uncertainty (GTU) departs from existing theories in essential ways. First, the thesis that information is statistical in nature is replaced by a much more general thesis that information is a generalized constraint, with statistical uncertainty being a special, albeit important case. Equating information to a generalized constraint is the fundamental thesis of GTU. Second, bivalence is abandoned throughout GTU, and the foundation of GTU is shifted from bivalent logic to fuzzy logic. As a consequence, in GTU everything is or is allowed to be a matter of degree or, equivalently, fuzzy. Concomitantly, all variables are, or are allowed to be granular, with a granule being a clump of values drawn together by a generalized constraint. And third, one of the principal objectives of GTU is achievement of NL-capability, that is, the capability to operate on information described in natural language. NL-capability has high importance because much of human knowledge, including knowledge about probabilities, is described in natural language. NL-capability is the focus of attention in the present paper. The centerpiece of GTU is the concept of a generalized constraint. The concept of a generalized constraint is motivated by the fact that most real-world constraints are elastic rather than rigid, and have a complex structure even when simple in appearance. The paper concludes with examples of computation with uncertain information described in natural language.  相似文献   

20.
The essence of intelligence is to use certain abilities to obtain knowledge, to use that knowledge, and to operate with that knowledge. New knowledge learned by a human is often related to old existing knowledge, and sometimes we could have more conceptual knowledge based on old knowledge. So, the knowledge in the brain exists in a related structural form, and this structure is dynamic, and therefore is evolvable. Based on the understanding of the real process of learning by a human being, we discuss how to make a model to describe the dynamic structure of knowledge. This model is also a principle of artificial brain design. Most of the knowledge a child learns is from natural language and perception information, and we define this as semantic knowledge. The model to describe the process and structure of knowledge growing in a network form is called a K-net. It is a dynamic network with two main dynamics: one is new knowledge added, and the other is aggregating knowledge existing in the network with some probability. Under these very natural conditions, we found that the network is originally a simple random net, and then some characteristics of a complex network gradually appear when more new knowledge is added and aggregated. A more interesting phenomenon is the appearance of a random hierarchical structure. Does this mean emergence?  相似文献   

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