PERFORMANCE OF SIMPLE-ENCODING IRREGULAR LDPC CODES BASED ON SPARSE GENERATOR MATRIX

A new method for the construction of the high performance systematic irregular low-density paritycheck （LDPC） codes based on the sparse generator matrix （G-LDPC） is introduced. The code can greatly reduce the encoding complexity while maintaining the same decoding complexity as traditional regular LDPC （H-LDPC） codes defined by the sparse parity check matrix. Simulation results show that the performance of the proposed irregular LDPC codes can offer significant gains over traditional LDPC codes in low SNRs with a few decoding iterations over an additive white Gaussian noise （AWGN） channel.

MATRIX PRODUCT CODES WITH ROSENBLOOM-TSFASMAN METRIC

In this article, the Rosenbloom-Tsfasman metric of matrix product codes over finite commutative rings is studied and the lower bounds for the minimal Rosenbloom- Tsfasman distances of the matrix product codes axe obtained. The lower bounds of the dual codes of matrix product codes over finite commutative Frobenius rings are also given.

A Construction of Multi-Sender Authentication Codes from Eigenvalues and Eigenvectors of the Matrix Over Finite Fields

We construct one multi-sender authentication code by algebraic combination method from eigenvalues and eigenvectors of the matrix over nite elds. Some parameters and the probabilities of three kinds of successful attack of this code are also computed. For multi-sender authentication code,it allows a group of senders to construct an authenticated message for a receiver such that the receiver can verify authenticity of the received message.

On the Construction of the Kernel Matrix by Primitive BCH Codes for Polar Codes

The polar codes defined by the kernel matrix are a class of codes with low coding-decoding complexity and can achieve the Shannon limit. In this paper, a novel method to construct the 2n-dimensional kernel matrix is proposed, that is based on primitive BCH codes that make use of the interception, the direct sum and adding a row and a column. For ensuring polarization of the kernel matrix, a solution is also put forward when the partial distances of the constructed kernel matrix exceed their upper bound. And the lower bound of exponent of the 2n-dimensional kernel matrix is obtained. The lower bound of exponent of our constructed kernel matrix is tighter than Gilbert-Varshamov (G-V) type, and the scaling exponent is better in the case of 16-dimensional.

Data Matrix码识别技术研究

二维条码本身具有高容量、高密度、纠错能力强、安全强度高等特点,使得二维条码作为信息的载体在信息自动化领域发挥着越来越重要的作用。该文提出了一种基于手机应用平台的DM码识别方案,并对图像识别过程进行了优化。

刀具柱面Data Matrix码几何畸变的仿真分析

分析了刀具柱面Data Matrix(DM)码几何畸变的原理与过程,利用透视投影的方法建立了柱面DM码的几何畸变模型并对其进行仿真.结果表明,该模型较好地模拟了DM码在刀具柱面的几何畸变状况.通过仿真分析,获得了在一定曲率柱面上标刻DM码的合适尺寸以及采集过程中相机的合适几何参数.

基于Reed-Solomon算法的DataMatrix条码纠错码的研究

DataMatrix是一种矩阵二维条码,具有信息密度大、容量高、面积小等优点,同时,其译码时受噪声干扰也较大,因此,DataMatrix二维条码采用了ReedSolomon算法作为纠错码,可以有效地排除干扰进行纠错。首先介绍DataMatrix条码的特点,然后详细介绍了ReedSolomon算法的原理和伽罗华域的基本运算规则和构造规则,重点分析研究他在DataMatrix二维条码中的应用,构造了他的实现算法和其纠错编码的实现电路并通过实例进行了具体的说明,同时讨论了RS的译码步骤。

基于手机平台的Data Matrix 2维条码识别

传统的条码图像采集和识别是通过工业扫描枪。近年来,随着移动增值业务和3G技术的发展,2维条码在手机设备的应用中得到飞速发展。以Data Matrix为例,研究了基于嵌入式手机设备的2维条码识别技术。首先根据Data Matrix条码的特点,给出了一种基于链码跟踪和线段检测的快速Data Matrix检测算法。接着分析了条码信号经过点扩展函数卷积后的降质模型,并利用维纳滤波对条码信号进行反模糊滤波。最后,针对透视畸变的现象,设计了一种适合于嵌入式手机设备的快速反透视算法。实验结果表明,提出的识别算法具有优秀的性能,显著提高了条码的识别率,满足了实际使用的要求。

P-code位矩阵方法与扩展研究

以磁盘冗余阵列(Redundant Array of Inexpensive Disks,RAID)技术中新出现的P-code编码为主要对象,进行了其构造方法、编码及译码算法的详细分析,并首次运用位矩阵(Binary Distribution Matrix,BDM)的方法分析和研究了P-code码。在此基础上,对当前主要RAID-6编码的扩展即更多磁盘数量的容错问题进行了总结与探讨,提出了P-code等垂直最大距离可分码(Maximum Distance Separable,MDS)的扩展将是该领域未来研究的新方向和难点。

基于Reed-Solomon码的Data Matrix条码纠错研究

为了研究Data Matrix条码的纠错能力,首先介绍了Data Matrix条码的特点和Reed-Solomon码的基本概念;接着研究了Reed-Solomon码在Data Matrix二维条码中的应用,重点分析了Data Matrix二维条码中Reed-Solomon编、解码的基本原理与步骤,并用C语言实现它的编、解码算法;最后对Reed-Solomon码的纠错能力进行了测试。实验结果表明,Data Matrix二维条码采用Reed-Solomon码作为纠错码,可以有效地排除干扰并进行纠错。

基于Data Matrix码的煤矿设备信息管理

为提高煤矿设备管理效率,提出了一种基于Data Matrix码的煤矿设备信息管理方法。该方法分为煤矿设备信息Data Matrix码生成和识别2个部分:将存储设备运行信息的服务器地址同设备固有信息进行编码,生成煤矿设备信息Data Matrix码;通过智能移动终端采集煤矿设备上的Data Matrix码图像,对图像进行灰度化、中值滤波、二值化、Canny边缘检测等预处理后,采用改进的Hough变换检测Data Matrix码的L型直线,并进行倾斜校正操作,从而准确定位图像中Data Matrix码的坐标位置,再通过解码识别Data Matrix码包含的设备信息。该方法能准确记录和识别设备信息,提高设备管理效率。

畸变Data Matrix码图像的倾斜校正算法研究

针对Data Matrix码倾斜校正中需要多次旋转的问题,本文提出了一种畸变二维码倾斜校正方法。首先使用LoG算子对二值化后的图像进行边缘检测,再基于Data Matrix码的结构特征,通过Hough变换有效快速地确定定位符"L"所在的位置,并将"L"型交点用两条向量表示。然后通过向量叉乘计算出Data Matrix码的旋转角度、确定旋转方向,只需一次旋转即可实现倾斜校正。本文算法节省了Data Matrix码在图像恢复过程中所需的时间和工作量。

基于稀疏表示的Data Matrix码图像修复算法

稀疏表示理论凭借其建模简单、鲁棒性高与抗干扰能力强等优势成为研究热点,将稀疏理论应用于图像修复已成为图像处理领域新的研究方向。针对工业现场中常出现的被遮挡而不能识别的二维码图像,提出一种基于稀疏表示模型的块聚类图像修复算法。依据待修复图像内的有效信息,以固定重叠像素的方式将图像分块,分别对图像块使用欧几里得距离进行训练匹配,将得到的具有相似结构的图像块聚类为结构组作为图像稀疏表示的基本单位,利用每个结构组的估计来快速学习字典。通过使用分离迭代与优化梯度算法对组稀疏表示模型的L1范数最小化问题进行求解,提高了修复算法的鲁棒性。实验结果表明,该算法能够很好地修复被遮挡、划痕或像素丢失等受损的Data Matrix码图像,较大地提高了条码的识别率。

刀具标识中Data Matrix的编码和解码技术研究

为了提高数控车间刀具库存管理和生产过程追踪中信息采集的准确性和实时性,提出了一种刀具信息自动采集方案并加以实现。基于Data Matrix编码原理将刀具信息转换成机读二维码,使用激光标刻技术在刀具表面实现该二维码的直接标刻,然后对其进行扫描并对图像进行倾斜校正,最后通过Reed-Solomon算法对识读结果进行纠错,实现了刀具信息自动采集的准确性和实时性。

基于链码跟踪的Data Matrix二维条码快速识别

为实现工业现场中Data Matrix二维条码的快速识别,提出一种基于链码跟踪、直线段提取的条码快速识别方法。首先采用Sobel算子提取图像边缘;然后基于链码跟踪方法,跟踪图像的边缘点,记录链码;接着根据快速直线段提取方法,将直线相似度低于阈值的线段剔除,结合线形连接方法合并断裂线段,并使用长度判别剔除不可靠的线段;最后结合Data Matrix二维条码的特征,定位Data Matrix二维条码。实际测试表明,该识别方法能够快速、准确地定位二维条码区域,识别正确率可达99.39%以上,具有实时性强、可靠性好等特点,满足工业现场要求。

High Quality Audio Object Coding Framework Based on Non-Negative Matrix Factorization

Object-based audio coding is the main technique of audio scene coding. It can effectively reconstruct each object trajectory, besides provide sufficient flexibility for personalized audio scene reconstruction. So more and more attentions have been paid to the object-based audio coding. However, existing object-based techniques have poor sound quality because of low parameter frequency domain resolution. In order to achieve high quality audio object coding, we propose a new coding framework with introducing the non-negative matrix factorization(NMF) method. We extract object parameters with high resolution to improve sound quality, and apply NMF method to parameter coding to reduce the high bitrate caused by high resolution. And the experimental results have shown that the proposed framework can improve the coding quality by 25%, so it can provide a better solution to encode audio scene in a more flexible and higher quality way.

Construction of deterministic sensing matrix and its application to DOA estimation

Compressive sensing（CS） has emerged as a novel sampling framework which enables sparse signal acquisition and reconstruction with fewer measurements below the Nyquist rate.An important issue for CS is the construction of measurement matrix or sensing matrix.A new deterministic sensing matrix,named as OOC-B,is proposed by exploiting optical orthogonal codes（OOCs）,Bernoulli matrix and Singer structure,which has the entries of 0,＋1 and-1 before normalization.We have proven that the designed deterministic matrix is asymptotically optimal.In addition,the proposed deterministic sensing matrix is applied to direction of arrival（DOA） estimation of narrowband signals by CS arrays（CSA）processing and CS recovery.Theoretical analysis and simulation results show that the proposed sensing matrix has good performance for DOA estimation.It is very effective for simplifying hardware structure and decreasing computational complexity in DOA estimation by CSA processing.Besides,lower root mean square error（RMSE） and bias are obtained in DOA estimation by CS recovery.

Quantum quasi-cyclic low-density parity-check error-correcting codes

In this paper, we propose the approach of employing circulant permutation matrices to construct quantum quasicyclic （QC） low-density parity-check （LDPC） codes. Using the proposed approach one may construct some new quantum codes with various lengths and rates of no cycles-length 4 in their Tanner graphs. In addition, these constructed codes have the advantages of simple implementation and low-complexity encoding. Finally, the decoding approach for the proposed quantum QC LDPC is investigated.

PCB板复杂背景下的Data Matrix码定位与识别

工业二维码的应用环境通常比较恶劣,二维码识别通常伴随着噪声、过曝等问题.对工业二维码进行粗定位时,采用基于亮度、对比度和伽玛变换提高了图像整体的对比度,为阈值分割提供良好的图像基础.再对预处理后的图像采用大律法分割使得背景和前景分离并计算连通域面积和个数,定位可能存在二维码的图像区域.根据DataMatrix码的特征,提出了一种基于Shi-Tomasi角点密度的DataMatrix码快速定位算法.识别时针对二维码过曝的问题,提出了一种改进的伽玛变换算法有效地增强了图像的对比度,为识别提供良好的图像基础.

Half Rate Quasi Cyclic Low Density Parity Check Codes Based on Combinatorial Designs

This paper presents new half rate Quasi Cyclic Low Density Parity Check (QC- LDPC) codes formed on the basis of combinatorial designs. In these codes, circulant matrices of the parity check matrix are formed on the basis of subsets in which the difference between any two elements of a subset is unique with all differences obtained from the same or different subsets. This structure of circulant matrices guarantees non-existence of cycle-4 in the Tanner graph of QC-LDPC codes. First, an irregular code with girth 6 constituted by two rows of circulant matrices is proposed. Then, more criteria will be considered on the structure of subsets with the mentioned feature aiming to represent a new scheme of regular QC-LPDC codes with girth at least 8. From simulations, it is confirmed that codes have similar to or better performance than other well-known half rate codes, while require lower complexity in their design.