一种最优化链码指纹二值细化图像压缩编码

提出了一种适合于对线状结构的条形纹线二值图像进行压缩的最优化Freeman链码压缩算法——Freeman差分链码Huffman编码。与传统的Freeman链码相比,提出的压缩算法是基于Freeman链码、差分编码和Huffman编码的一种混和编码方式。通过理论分析和在指纹二值细化图上的实验结果证明,对于指纹二值细化图像,本算法优于现有的链码压缩二值图像的算法,针对于线状结构的条形纹线二值图像,本算法也优于其他压缩算法。其平均码长为1.7651bits,低于8方向Freeman链码或者Freeman差分链码的3bits的平均码长。     

An efficient chain code with Huffman coding

This paper presents a new chain code based on the eight-direction Freeman code. Each element in the chain is coded as a relative angle difference between it and the previous element. Statistical analysis showed that the probabilities of the Freeman codes differ importantly. Therefore, the Huffman coding was applied. The proposed chain code requires 1.97 bits/code, its chain length is short, it allows the representation of non-closed patterns, and it is rotationally independent.     

基于Freeman链码的圆识别方法

在研究圆的Freeman链码性质并得出圆的Freeman链码与其对称链码的关系后,提出了一种基于Freeman链码性质的圆识别方法,通过圆的Freeman链码与其对称链码的相似度和奇偶码值出现的次数对圆进行识别。实验结果表明,该方法识别准确、效率高。     

矩形点阵上八近邻图像的链码转换算法

给出了矩形点阵上八近邻图像的顶点链码（VCC）、Freeman链码和边界链码之间的转换算法，给出了图像边界的边界链码与顶点链码之间的相互转化算法和顶点链码与Freeman链码之间的相互转换算法，于是可以方便地直接由一种链码得到其他的链码表示，由某种链码获得的图像信息也为其他链码所共享．     

矩形点阵上链码的转换算法

链码是图像处理和图像识别中的一个重要工具.给出了四近邻图像的顶点链码（VCC）、Freeman链码和边界链码之间的转换算法,这样只要获得一种链码就可以得到其它的链码表示,由某种链码获得的图像信息也为其他链码所共享.     

一种新压缩顶点链码

链码是一种以较少的数据存储表示线条、曲线和区域边界的编码技术。为进一步提高链码的压缩效率,提出了一种新的压缩顶点链码：改进的正交3方向顶点链码（IO3DVCC）。IO3DVCC将顶点链码（VCC）的统计特征与正交3方向链码（3OT）的方向特征相结合,共设5个码值。码值1将VCC中的1、3组合和3、1组合归并表示,码值2与VCC的对应码值表达相同,码值3与3OT中的码值2表达相同,码值4和码值5分别对应2个连续的新链码码值1和8个连续的VCC码值2。新链码基于Huffman编码,为不定长编码。针对100幅图像的轮廓边界,统计并计算了IO3DVCC与改进的相对8方向Freeman链码（ERD8FCC）、基于算数编码的变长相对四方向Freeman链码（AVRF4）、基于算数编码的正交3方向链码（Arith_3OT）、压缩VCC （CVCC）和改进的CVCC （ICVCC）6种链码各码值出现的概率、平均码值表达能力、平均码长和链码效率。实验结果表明,IO3DVCC效率最高。针对随机选择的20幅轮廓边界图像,统计并计算了IO3DVCC、Arith_3OT和ICVCC3种链码表达的总码数、二进制总位数,以及相对于8方向Freeman链码的压缩比率。实验结果表明,IO3DVCC的压缩效果最好。     

一种优化的Freeman链码及其在工程图纸绘制中的应用

提出一种适合于线状结构二值图象的最优化Ｆｒｅｅｍａｎ链码,并讨论其在绘图仪图纸绘制中的应用。与传统的Ｆｒｅｅｍａｎ链码相比,本文的方法是基于数字化点阵图象的无失真编码。根据图象中直线段长度的统计特性选择码长,以使编码压缩率为最高。理论分析和实验结果证明,本方法优于已有的方法并易于工程图纸的图象存储和在绘图仪上的输出。     

压缩链码的研究

对图像处理及模式识别中的链码技术进行研究.首先针对具有二位码长的顶点链码只有3个码值的情况,在不增加码长的情况下对其增加了一个码值,大大提高了其表达能力.其次,同样根据顶点链码的上述冗余情况对其进行了不等长编码压缩.然后,在上述两种改进链码的基础上,根据大量的统计数据提出了一种基于Huffman编码的新的压缩链码.文中还提出了一种对链码的评价方法.最后,用该评价方法和对实际图像的实验测试对所提出的链码和4种已有链码进行了理论上和实用方面的比较.比较的结果显示该文提出的压缩链码效率最高.     

An enhanced one-dimensional SPIHT algorithm and its implementation for TV systems

In general, to achieve high compression efficiency, a 2D image or a 2D block is used as the compression unit. However, 2D compression requires a large memory size and long latency when input data are received in a raster scan order that is common in existing TV systems. To address this problem, a 1D compression algorithm that uses a 1D block as the compression unit is proposed. 1D set partitioning in hierarchical trees (SPIHT) is an effective compression algorithm that fits the encoded bit length to the target bit length precisely. However, the 1D SPIHT can have low compression efficiency because 1D discrete wavelet transform (DWT) cannot make use of the redundancy in the vertical direction. This paper proposes two schemes for improving compression efficiency in the 1D SPIHT. First, a hybrid coding scheme that uses different coding algorithms for the low and high frequency bands is proposed. For the low-pass band, a differential pulse code modulation–variable length coding (DPCM–VLC) is adopted, whereas a 1D SPIHT is used for the high-pass band. Second, a scheme that determines the target bit length of each block by using spatial correlation with a minimal increase in complexity is proposed. Experimental results show that the proposed algorithm improves the average peak signal to noise ratio (PSNR) by 2.97 dB compared with the conventional 1D SPIHT algorithm. With the hardware implementation, the throughputs of both encoder and decoder designs are 6.15 Gbps, and gate counts of encoder and decoder designs are 42.8 K and 57.7 K, respectively.     

Compressed vertex chain codes

This paper introduces three new vertex chain codes. Firstly, considering that the vertex chain code uses 2 bits to represent only three code elements, a new code is introduced without increasing the average bits per code. The second case introduces a variable-length vertex chain code. Finally, a new compressed chain code is proposed based on the Huffman method. The continuation introduces a method for quantificationally evaluating the efficiency of chain codes. The efficiencies of the new vertex chain codes are then compared theoretically and practically against the most popular chain codes. The result of the comparison shows that the new compressed chain code is the most efficient.     

基于自适应链码的棉种周长测量

在棉种实时检测系统中,为了识别破损棉种,必须提取棉种的边缘并计算其周长。传统的边缘提取方法有Sobel、Robert等微分算子,以及数学形态学方法和小波变换方法。但是在实时系统中,图像处理速度是影响实时性的关键因素。Freeman链码是图像处理中表示轮廓形状的方法之一,由提取的链码可以得到曲线（包括直线）的曲率、曲线的特征点等,而这些特征是图像压缩、图像重建、图像匹配的依据。由Freeman链码方法提取的图像边缘是单像素的,因此采用这种方法来计算棉种的周长。通过与Sobel、Robert等边缘提取方法进行比较,可以证明运用链码方法求周长,其搜索时间短,计算准确,尤其适用于以快速准确为目标的实时系统。     

Web-based simulating system for modeling earthquake seismic wavefields on the grid

We have developed the SYNSEIS (SYNthetic SEISmogram) tool within the GEON (GEOscience Network) project to enable efficient computations of synthetic seismic waveforms for research and education. SYNSEIS is built as a distributed system to support the calculation of synthetic seismograms in 2D/3D media. The underlying simulation software is a finite difference code, E3D, developed by LLNL (S. Larsen). This code is embedded within the SYNSEIS environment and used by our SYNSEIS tool to simulate seismic waveforms of either earthquakes or explosions at regional distances (<1000 km). The SYNSEIS architecture is based around a Web service model. Especially, the computing Web services seamlessly access Grid computing resources by hiding the complexity of grid technologies. Even though the Grid computing is well-established in many computing communities, its use among domain scientists still is not trivial because of multiple levels of complexities encountered. We have also developed the grid-enabling E3D application code which takes our own dialect XML inputs that include geological models that are accessible through standard Web services. Also, the XML inputs for this application code contain structural geometries, source parameters, seismic velocity, density, attenuation values, number of time steps to compute, and number of stations.In this paper, we emphasize the development of a state-of-the-art web-based scientific computational environment. Our system can be used to promote an efficient and effective modeling environment to help scientists as well as educators in their daily activities and speed up the scientific discovery process.     

A reversible data hiding scheme based on the Sudoku technique

Data hiding, also known as information hiding, plays an important role in information security for various purposes. Reversible data hiding is a technique that allows distortion-free recovery of both the cover image and the secret information. In this paper, we propose a new, reversible data hiding scheme that is based on the Sudoku technique and can achieve higher embedding capacity. The proposed scheme allows embedding more secret bits into a pair of pixels while guaranteeing the good quality of the stego-image. The experimental results showed that the proposed scheme obtained higher embedding capacity than some other previous schemes. In addition, our proposed scheme maintained the good visual quality of the stego-image (i.e., PSNR > 46 dB), which outperforms some existing schemes.     

A route and speed optimization model to find conflict-free routes for automated guided vehicles in large warehouses based on quick response code technology

This paper focuses on exploring conflict-free routes for automated guided vehicles (AGVs) based on quick response (QR) code technology. Intelligent warehousing has become an industrial development trend, with an increasing number of enterprises deploying AGVs based on QR code technology for transportation tasks, especially in large warehouses. Unlike the early single lane path following navigation systems, AGVs using QR code technology can freely switch tracks at any position. And two AGVs can be accommodated side by side. The conditions of conflict-free routes are analyzed firstly when AGVs use QR code navigation system. After that, a route and speed optimization model (RSOM) that aims at minimizing energy consumption and taking conflict-free routes with time windows as the constraint condition is established. Then a branch-and-bound (B&B) algorithm scheme is proposed by altering AGV routes or speed to arrive at schemes with conflict-free routes to complete transportation tasks. Lastly, the effectiveness and validity of our proposed model and algorithm are verified by numerical examples and a case study. The results show that resolving conflicts during route planning for AGVs guided through QR code have advantages over avoiding collision in the running phase by technology and path following techniques in both aspects of solution time and energy. In addition, the established B&B algorithm has better performance than the rapid-exploring random tree (RRT) algorithm in numerical examples. The gaps between them widen as the size of AGVs increases. The research work has potential for application to meet the requirements of AGV development.     

对Freeman链码分析的角点检测算法

针对传统的基于轮廓曲线的角点检测算法需要计算曲率和选取阈值的不足,提出一种对Freeman链码分析的角点检测算法,首先通过图像边缘检测,轮廓提取得到轮廓的Freeman链码,当链码发生变化时分析其连续前后多个点的链码是否符合一定的规则来判定角点,无需经过传统的角点阈值选取,曲率计算等步骤.实验通过与He&Yung、CPDA、Fast-CPDA和ARCSS角点检测器比较,结果表明本文算法在角点检测时准确率（ACU）最高;在变换实验中,本算法的平均重复率（AR）最高,由此可以得出本算法具有良好的角点检测性能.     

基于Freeman链码连通体边界检测及其在坭兴陶图像中的应用

Freeman链码分为八方向和四方向。介绍Freeman链码的原理、记录方式、链码的获取并给出链码的核心代码。对图像采用八方向的链码方法记录图像的边界,实验结果表面采用八方向链码的方式提取图像的边界特征效果较好,并应用到坭兴陶图像中。     

基于二级复合链码的七段数字识别方法

针对动态数字图像的识别问题,提出基于二级复合链码的七段数字识别方法。对细化后的目标图像进行第1级8方向Freeman链码描述,在此基础上,进行第2级4方向Freeman链码描述,得到的复合链码与七段数字具有单一映射关系。在无线瓦斯检测系统中的应用结果表明,该方法具有较高的识别率和执行效率。     

A novel adaptive cuckoo search algorithm for intrinsic discriminant analysis based face recognition

This paper presents a novel adaptive cuckoo search (ACS) algorithm for optimization. The step size is made adaptive from the knowledge of its fitness function value and its current position in the search space. The other important feature of the ACS algorithm is its speed, which is faster than the CS algorithm. Here, an attempt is made to make the cuckoo search (CS) algorithm parameter free, without a Levy step. The proposed algorithm is validated using twenty three standard benchmark test functions. The second part of the paper proposes an efficient face recognition algorithm using ACS, principal component analysis (PCA) and intrinsic discriminant analysis (IDA). The proposed algorithms are named as PCA + IDA and ACS–IDA. Interestingly, PCA + IDA offers us a perturbation free algorithm for dimension reduction while ACS + IDA is used to find the optimal feature vectors for classification of the face images based on the IDA. For the performance analysis, we use three standard face databases—YALE, ORL, and FERET. A comparison of the proposed method with the state-of-the-art methods reveals the effectiveness of our algorithm.     

图象边界的链码表示研究

图象边界表示在模式识别、图象处理以及计算机视觉等领域扮演着十分重要的角色。本文研究了图象边界的链码表示,提出一种改进的链码表示方法。该方法通过二元组代替方向编号逐一编码方法,使用一个字节的高低位存取二元组的两个数值,节省了存储空间。理论分析和实验结果表明,与常用链码相比,该方法有效缩短了链码长度,能提高边界重绘速度,具有较强的实用性。