一种低复杂度的HEVC帧内快速编码算法

为了降低高效视频编码(HEVC)帧内编码复杂度,提出一种HEVC帧内快速编码算法。根据视频图像的纹理复杂性,提前跳过或者中止部分尺寸的编码单元(CU)的划分,减少CU深度遍历区间;同时,根据粗选过程后预测模式和代价值的统计特性采用阈值法或者梯度模式直方图法进一步筛选掉粗选后可能性较小的预测模式,从而减少最后进行率失真(RD)代价计算的帧内预测模式数量,进一步降低编码复杂度。实验结果表明,本文算法与HEVC原始平台相比,在全I帧编码模式下编码时间平均减少42.20%,码率(BR)上升约1.75%,峰值信噪比(PSNR)降低了0.108dB,有利于实时应用。     

x265的低复杂度帧内编码快速算法

为了降低x265的帧内编码复杂度,减少编码所需时间,本文针对新一 代高效视频编码标准(HEVC)帧内编码单元(CU)划分以 及预测单元(PU)模式选择的快速算法进行研究。采用经典的差分矩阵计算纹理复杂度,提出 了一种根据当前编码单元子块的纹理复杂 相似度与其编码所需要的总比特数以及量化参数之间的关系作为提前终止CU划分的判决 条件,通过增加SATD的计算进一 步减少PU模式选择的RDO候选列表的个数从而减少率失真代价计算的快速算法。实验结果 表明,与x265的标准算法相比, 该算法在平均峰值信噪比(PSNR)仅减少0.028dB和码率平均增加1.27%的情况下,能够平均减少32.34%的帧内编 码时间。     

一种快速有效的自适应算术编码

介绍了算术编码的原理和基于模型的自适应算术编码算法，并利用二进制索引树这样一个高效率的数据结构对传统的0阶自适应算术编码进行了改进。实验表明，无论对于高度集中的数据集还是对于分布较为均匀的数据集，在运行时间上新算法都有较大的改进。     

确定周期为P n的二元序列k-错复杂度曲线的快速算法

设计了一个确定周期为P^n的二元序列k-错复杂度曲线的算法,这里p为素数,并且2是模P^2的一个本原根。该算法分别推广了魏-白-肖和魏-董-肖计算二元P^n周期序列线性复杂度与k-错复杂度的算法。     

A fast algorithm for the performance index of a telecommunicationnetwork

A performance index for a telecommunication network is defined as a composite index integrating the important measures of both reliability and capacity. In this index the network states that permit a flow capability less than the maximum, are not totally ignored but are assigned a normalized weight less than one. A fast method is proposed for deriving the symbolic expression of the performance index in a compact form. Because the capacity of several subnetworks must be computed, an efficient procedure for capacity determination is also suggested. An example illustrates the procedure and points out the simplicity of the resulting expression for the performance index     

基于PCNN和BWT的图像融合算法

提出了一种新型图像融合算法.首先,对待融合的两幅图像进行双正交小波分解得到两组多尺度图像;接着,取其中任意一组作为主PCNN的输入、另一组相应的图像作为从PCNN的输入,在每次迭代时,经并行PCNN点火后,得到一系列多尺度融合图像;然后,对它们进行双正交小波重构得到每次迭代的融合结果,并计算每次迭代结果的信息熵,取信息熵值最大的融合图像作为最终结果.大量的实验以及与其他融合算法的比较分析,表明了本文算法的有效性和优越性.     

A fast algorithm for reduced complexity sequence estimationachieving the optimum error exponent

A reduced complexity sequence estimator is presented which discards certain trellis paths based on their path metric and the minimum Euclidean distance in the trellis. An upper bound for the average number of retained paths is derived and the receiver is shown to achieve the optimum error exponent of the maximum likelihood sequence estimator. A fast implementation is proposed and simulation results are presented     

周期为N=n2v的序列线性复杂度的快速算法

文中利用广义离散傅里叶变换对GF（2）上周期为N＝n2^v（gcd(n,2）＝1）序列进行了研究，给出了求周期为N＝n2^v的序列线性复杂度的快速算法，并得到了关于GF（2）上多项式的Hasse导数的一些新结果。     

一种快速有效的帧级码率控制算法

基于对码率控制算法的研究，取H．263 的TMN8码率控制算法和DivX的平均码率控制算法之长，提出了一种新型帧级码率控制算法，给出了实现算法的步骤和软件流程，实验表明该码率控制算法快速、简便、有效，并可将它应用于视频监控系统中。     

A fast algorithm for determining the complexity of a binary sequence with period2^n(Corresp.)

The complexity of a periodic sequence(s)is defined to be the least number of stages in a linear feedback shift register that generates(s).     

Error performance of preamplified optical PPM systems with finite extinction ratios

In this paper, we present an analytical study of the error performance in optically preamplified, M-ary pulse position modulation, in free-space optical communication systems with finite extinction ratios. We derive a theoretical expression for the probability of bit error and compute it numerically for different symbol sizes and extinction ratios. We also provide the power penalty due to a finite extinction ratio for both coded and uncoded systems. The study shows that, in certain cases and for a given extinction ratio, lower symbol sizes may yield an error performance similar to that achieved by higher symbol sizes.     

A recursive least M-estimate algorithm for robust adaptive filtering in impulsive noise: fast algorithm and convergence performance analysis

This paper studies the problem of robust adaptive filtering in impulsive noise environment using a recursive least M-estimate algorithm (RLM). The RLM algorithm minimizes a robust M-estimator-based cost function instead of the conventional mean square error function (MSE). Previous work has showed that the RLM algorithm offers improved robustness to impulses over conventional recursive least squares (RLS) algorithm. In this paper, the mean and mean square convergence behaviors of the RLM algorithm under the contaminated Gaussian impulsive noise model is analyzed. A lattice structure-based fast RLM algorithm, called the Huber Prior Error Feedback-Least Squares Lattice (H-PEF-LSL) algorithm is derived. Part of the H-PEF-LSL algorithm was presented in ICASSP 2001. It has an order O(N) arithmetic complexity, where N is the length of the adaptive filter, and can be viewed as a fast implementation of the RLM algorithm based on the modified Huber M-estimate function and the conventional PEF-LSL adaptive filtering algorithm. Simulation results show that the transversal RLM and the H-PEF-LSL algorithms have better performance than the conventional RLS and other RLS-like robust adaptive algorithms tested when the desired and input signals are corrupted by impulsive noise. Furthermore, the theoretical and simulation results on the convergence behaviors agree very well with each other.     

Product accumulate codes: a class of codes with near-capacity performance and low decoding complexity

We propose a novel class of provably good codes which are a serial concatenation of a single-parity-check (SPC)-based product code, an interleaver, and a rate-1 recursive convolutional code. The proposed codes, termed product accumulate (PA) codes, are linear time encodable and linear time decodable. We show that the product code by itself does not have a positive threshold, but a PA code can provide arbitrarily low bit-error rate (BER) under both maximum-likelihood (ML) decoding and iterative decoding. Two message-passing decoding algorithms are proposed and it is shown that a particular update schedule for these message-passing algorithms is equivalent to conventional turbo decoding of the serial concatenated code, but with significantly lower complexity. Tight upper bounds on the ML performance using Divsalar's (1999) simple bound and thresholds under density evolution (DE) show that these codes are capable of performance within a few tenths of a decibel away from the Shannon limit. Simulation results confirm these claims and show that these codes provide performance similar to turbo codes but with significantly less decoding complexity and with a lower error floor. Hence, we propose PA codes as a class of prospective codes with good performance, low decoding complexity, regular structure, and flexible rate adaptivity for all rates above 1/2.     

OLRIV: a new fast adaptive algorithm for rectangular-block Toeplitzsystems

In this paper, we propose a new algorithm for solving overdetermined systems when they are rectangular-block Toeplitz (the blocks can have more rows than columns). It is based on the expression of the matrix of the system to solve as the intercorrelation between two vectorial processes, namely, the original and the instrumental processes. The instrumental process has generally more components than the original one; therefore, it takes the overdetermined character of the system into consideration. The proposed algorithm known as the overdetermined lattice recursive instrumental variable (OLRIV) belongs to the fast-RLS family and lies on a double lattice structure, where one lattice performs the prediction of the original process and the other one the prediction of the instrumental process. The geometric complete derivation of the proposed algorithm is given in the paper. Afterwards, we show how OLRIV can be applied to perform blind adaptive identification of AR channels using high order statistics, where the systems to solve are often overdetermined to ensure identifiability. Both the scalar and the vectorial cases are investigated. Simulation results are finally given to show the performances of OLRIV     

EFBLA: a two-phase matching algorithm for fast motion estimation

A novel motion estimation algorithm that contains edge matching and block matching is presented. The edge matching reduces candidates for the block matching that performs accurate searching. Thus, the two-phase procedure speeds up motion estimation. As a result, edge-matching first block-matching last algorithm (EFBLA) may significantly save the computation load by 93.9%.     

Motion estimation algorithm with low complexity for videocompression

The author presents a new motion estimation method which reduces the computational complexity in video compression. This is achieved by skipping the motion estimation operation for macro-blocks, where it is determined that this operation does not need to be carried out     

On the estimation of the order of a Markov chain and universal datacompression

The authors estimate the order of a finite Markov source based on empirically observed statistics. The performance criterion adopted is to minimize the probability of underestimating the model order while keeping the overestimation probability exponent at a prescribed level. A universal asymptotically optimal test, in the sense just defined, is proposed for the case where a given integer is known to be the upper bound of the true order. For the case where such a bound is unavailable, an alternative rule based on the Lempel-Ziv data compression algorithm is shown to be asymptotically optimal also and computationally more efficient     

The Lempel-Ziv algorithm and message complexity

Data compression has been suggested as a nonparametric way of discriminating between message sources. Compressions obtained from a Lempel-Ziv algorithm for relatively short messages, such as those encountered in practice, are examined. The intuitive notion of message complexity has less connection with compression than one might expect from known asymptotic results about infinite messages. Nevertheless, discrimination by compression remains an interesting possibility     

A fast algorithm for determining the linear complexity of asequence with period pn over GF(q)

A fast algorithm is presented for determining the linear complexity of a sequence with period pⁿ over GF (q), where p is an odd prime, and where q is a prime and a primitive root (mod p²)     

脉压波形畸变校正及其快速算法设计

针对雷达信号实时处理中数字正交插值滤波器引起脉压波形畸变的现象,提出了一种新的波形优化方法,采用精确设计的匹配滤波器,消除了数字正交插值滤波器对脉压波形的失配影响,改进了脉压输出的幅度特性和相位特性,提高了检测性能.基于对任意长度序列进行优化的添零-分解FFT方法,提出了利用频域滤波实现大脉压比脉压的一种新的快速算法,当对非连续信号进行脉压时,显著减轻了运算负荷.