共查询到20条相似文献,搜索用时 15 毫秒
1.
We suggest a method of enumerative block encoding for sequences with constrained length of a run of zeros. Though the algorithm obtained coincides in form with the classical Bahl–Tang method, its application is extended to sequences with a wider class of constraints. We obtain recursion formulas for bit weights. 相似文献
2.
一种基于编码的识别手写数学符号方法 总被引:1,自引:0,他引:1
提出了一种对手写数学符号的识别方法,通过对数学符号的图象进行处理,然后对其进行编码,并采用模糊识别方法建立了识别函数。根据这一函数以求最佳匹配,试验结果表明,该方法有良好的识别性能。 相似文献
3.
The Lempel–Ziv universal coding scheme is asymptotically optimal for the class of all stationary ergodic sources. A problem of robustness of this property under small violations of ergodicity is studied. The notion of deficiency of algorithmic randomness is used as a measure of disagreement between data sequence and probability measure. We prove that universal compression schemes from a large class are nonrobust in the following sense: If the randomness deficiency grows arbitrarily slowly on initial fragments of an infinite sequence, then the property of asymptotic optimality of any universal compression algorithm can be violated. Lempel–Ziv compression algorithms are robust on infinite sequences generated by ergodic Markov chains when the randomness deficiency of their initial fragments of length n grows as o(n). 相似文献
4.
A. V. Anisimov 《Cybernetics and Systems Analysis》2003,39(5):633-643
This paper proposes to code integers and binary trees by linear forms of aun-1+bun-type, where un-1 and un-1 are adjacent members of some integer sequence. New prefix codes of integers are obtained. Such codes have better characteristics than the well-known Levenshtein code. Data compression by means of coding by linear forms is considered. Linear Fibonacci forms are studied in detail. 相似文献
5.
提出了一种使用分形映射实现图像小波子带系数编码的新的方案。利用小波各子带系数之间的相似性,定义了一种前后小波带内的父子节点间的映射结构关系,从而对Range块进行分形匹配。编码无须搜索Domain块,解码也无须迭代;并且对已编码的码流,采用算术编码以获得进一步的压缩。对图像序列,则采用条件补充(Conditional Replenishment)进行帧间编码,以减少算法运算量,增加实时性。实验结果 相似文献
6.
基于运动补偿的编码算法在运动图象压缩中得到非常广泛的研究和应用。该文提出一种基于数学形态学形态变换的运动补偿编码方法,通过形态变换确定对宏块中的不规则小块是否进行分割,以运动矢量比特数的增加换取帧间位移误差场(DFD)能量的大大降低,从而达到了提高压缩比(或相同压缩比下提高图象质量)的目的。 相似文献
7.
We address the problem of joint source-channel coding when variable-length codes are used for information transmission over a discrete memoryless channel. Data transmitted over the channel are interpreted as pairs (m
k
,t
k
), where m
k
is a message generated by the source and t
k
is a time instant when the transmission of the kth codeword begins. The decoder constructs an estimate of the transmitted sequence of pairs, and the kth decoding error is introduced as the event that the pair (m
k
,t
k
) does not belong to this sequence. We describe the maximum likelihood decoding algorithm and prove a lower bound on the exponent of the decoding error probability. For a subclass of discrete memoryless sources and discrete memoryless channels, this bound is asymptotically tight. 相似文献
8.
《Multimedia, IEEE Transactions on》2008,10(8):1648-1656
9.
为了在高信噪比条件下获得对彩色视频的高倍压缩 ,提出了 4维矩阵及 4维矩阵离散余弦变换理论 ,并将该理论应用于彩色视频编码 .基于 4维矩阵离散余弦变换的彩色视频编码方法将彩色视频的多个帧放在一个统一的数学模型 (即 ,4维矩阵 )中考虑 ,利用 4维矩阵离散余弦变换去除其间的各种相关性 ,并通过矢量量化对变换系数进行压缩编码 .其方法可以同时全面利用彩色视频图象相邻像素间、彩色空间 Y、U、V 3分量间 ,以及视频图象相邻帧之间的相关性 .实验结果证明 ,对可视电话和视频会议等应用中的彩色视频序列图象 ,利用该方法可在高信噪比条件下获得较高压缩比的编码效果 相似文献
10.
We present methods to generate rendering sequences for triangle meshes which preserve mesh locality as much as possible. This is useful for maximizing vertex reuse when rendering the mesh using a FIFO vertex buffer, such as those available in modern 3D graphics hardware. The sequences are universal in the sense that they perform well for all sizes of vertex buffers, and generalize to progressive meshes. This has been verified experimentally. 相似文献
11.
谢亮 《小型微型计算机系统》2006,27(8):1588-1591
针对多媒体无线通信的特点,提出了结合了自适应纠错技术与联合优化技术所提出的一种新策略.充分考虑了联合编码的自适应纠错特性和联合优化特性,在联合优化特性下分析了优化的信源编码算法和优化的信道编码算法.实验仿真的结果表明,该方法能够使图像数据在高码率下达到较好的抗噪性能. 相似文献
12.
本文提出了一种将概率神经网络进行改进井使其用于信源一信道联合编码的方法。改进后的网络可以利用信源中的相关性,对噪声有更好的鲁棒性。它的复杂度低,结构设计简单,并可以灵活地改变以适应不同的信源模型。 相似文献
13.
网络编码是一种新的网络传输技术,能够充分利用网络的理论组播速率上限.讨论了在网络编码下综合考虑编码开销和网络链路开销的网络总开销优化问题,将由网络编码引起的编码开销同样纳入优化问题的考虑范围.给出了2种各有优劣的网络信息流模型描述这一问题,并在不同模型下定义了2种开销的一般形式.由于这一优化问题属于NP难问题,目前一般采用启发式算法获得近似的优化解.随后的实验中,在不同规模的拓扑下对比了基于2种不同信息流模型的启发式算法的性能.由于考虑了编码开销使得联合优化问题远比链路开销优化问题复杂,模拟实验显示,只有当编码开销与链路开销价值系数之比达到1000以上时,才能获得比单纯链路优化更小的总开销.在提出基于遗传算法的方案之前,还简单地讨论了联合优化问题的复杂度. 相似文献
14.
Cernea D.C. Munteanu A. Alecu A. Cornelis J. Schelkens P. 《Multimedia, IEEE Transactions on》2008,10(3):503-513
This paper proposes a new approach for joint source and channel coding (JSCC) of meshes, simultaneously providing scalability and optimized resilience against transmission errors. An unequal error protection approach is followed, to cope with the different error-sensitivity levels characterizing the various resolution and quality layers produced by the input scalable source codec. The number of layers and the protection levels to be employed for each layer are determined by solving a joint source and channel coding problem. In this context, a novel fast algorithm for solving the optimization problem is conceived, enabling a real-time implementation of the JSCC rate-allocation. An instantiation of the proposed JSCC approach is demonstrated for MeshGrid, which is a scalable 3-D object representation method, part of MPEG-4 AFX. In this context, the L-inflnite distortion metric is employed, which is to our knowledge a unique feature in mesh coding. Numerical results show the superiority of the L-inflnite norm over the classical L-2 norm in a JSCC setting. One concludes that the proposed joint source and channel coding approach offers resilience against transmission errors, provides graceful degradation, enables a fast real-time implementation, and preserves all the scalability features and animation capabilities of the employed scalable mesh codec. 相似文献
15.
《Information Forensics and Security, IEEE Transactions on》2009,4(3):428-440
16.
We suggest a method for computing the number of dklr-sequences with given number of ones. Based on these results and the well-known method of Babkin and Cover, enumerative encoding and decoding for constant-weight dklr-sequences is obtained. 相似文献
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从概念格的概念矩阵出发,提出一种运用全1概念矩阵来生成概念格的算法(Algorithm of Generating Concept Lattice Using Universal Matrix,GCL1).对整体概念格的形式背景采用0-1矩阵来表达,扫描形式背景的行和列找出全部的全1矩阵,定义了最大秩全1矩阵的概念,并且证明了最大秩全1矩阵对应的结点一定是概念格中的概念;然后按全1矩阵的秩从大到小排序,并对非最大秩的全1矩阵进行扩充,从而得到概念结点,再对概念结点连接,分别建立子概念格;最后把这些子概念格合并生成整体概念格,并同时生成哈斯图.本文对所提出的GCL1算法进行了理论论证,并且通过实例运行,结果表明该算法的时间复杂度明显优于其它许多算法. 相似文献