On a method of binary-picture representation and its application to data compression

A method of representing a binary pictorial pattern is developed. Its original idea comes from a sequence of terminal symbols of a context-free grammar. It is a promising technique of data compression for ordinary binary-valued pictures such as texts, documents, charts, etc. Fundamental notions like complexity, primitives, simplifications, and other items about binary-valued pictures are introduced at the beginning. A simple context-free grammar G is also introduced. It is shown that every binary-valued picture is interpretable as a terminal sequence of that G. The DF-expression is defined as the reduced terminal sequence of G. It represents the original picture in every detail and contains no surplus data for reproducing it. A quantitative discussion about the total data of a DF-expression leads to the conclusion that any binary-valued picture with complexity less than 0.47 is expressed by the DF-expression with fewer data than the original ones. The coding algorithm of original data into the DF-expression is developed. It is very simple and recursively executable. Experiments were carried out using a PDS (photo digitizing system), where test pictures were texts, charts, diagrams, etc. with 20 cm × 20 cm size. Data compression techniques in facsimile were also simulated on the same test pictures. Throughout these studies it was made clear that the DF-expression is a very effective technique as a data compression for binary pictorial patterns not only because it yields high data compression but also because its coding and decoding algorithms are very feasible.     

VB中用数据库存储图片的方法研究

在VB编程中很多情况下会涉及到利用数据库对图像进行存取的问题,这对于初学者而言是个难点。总结了在VB编程基础上利用Access数据库直接存储图片,利用Access数据库存储图片路径、调用图片,以及将图片转换为二进制编码存入Access数据库三种较为简单的图片存储方法供初学者参考。三种方法各有利弊,若在VB编程中遇到此类问题,读者可以根据自己的需要选择合适的方法。     

On regular drawn symbolic picture languages

Drawn symbolic pictures are an extension of drawn pictures obtained by associating a symbol from an alphabet to each point of the picture. In the paper we will address some new interesting issues derived from the introduction of the symbols and we will identify the conditions, which ensure the preservation of properties holding for drawn pictures in the setting of the proposed extension.     

FANUC系统进给倍率PLC程序设计

主要介绍了格雷码与二进制码的不同、FANUC-0i MATE D进给倍率信号、CODB指令转换原理,介绍了用格雷码输出的编码开关配合CODB指令实现FANUC系统标准面板倍率开关修调的PLC程序设计方法。通过实例具体说明了CODB指令中数据表设置方法,同时用这种方法设计的倍率修调PLC程序在切削加工过程中当倍率变换时进给轴速度不会窜动,使运行保证平稳,不会影响到零件的加工精度。     

基于多帧灰度差异的视频对象分割

在新一代MPEG-4视频编码标准中,为了支持面向视频对象的编码和实现基于内容的应用,自动、快速地从视频场景中提取视频对象已成为一项关键技术,为此文章提出了一种基于多帧灰度差异的视频对象分割新算法。该算法首先采用多帧序列图像灰度差异的4次高阶统计量假设检验(HigherOrderStatistics,HOS),自动提取运动对象模板;然后利用数学形态学对模板作平滑和内部填充处理;最后将模板投影到原始灰度图,得到运动对象。实验结果表明,该方法能比较有效地分割视频对象。     

On generalized distance transformation of digitized pictures

In this paper, we present a generalization of the distance transformation of a digitized picture in two different aspects. First, we define the generalized distance transformation of a binary picture (GDTB). A subclass of GDTB, called a local minimum filter family of GDTB (LMF-GDTB), characterized by a series of local minimum filters with varying neighborhoods, is discussed in detail. A skeleton is defined for LMF-GDTB, and it is proved that any binary picture can be reconstructed exactly from its skeleton with the distance value on it. Second, the gray weighted distance transformation (GWDT) is extended to a generalized GWDT (GGWDT) by introducing an arbitrary initial picture. After the fundamental equation of GGWDT and its solution are derived, it is proved that an arbitrary gray picture is generated by iterative application of GGWDT from a uniquely determined elementary picture and a sequence of initial value pictures.     

A min-max medial axis transformation

Blum's medial axis transformation (MAT) of the set S of 1's in a binary picture can be defined by an iterative shrinking and reexpanding process which detects ``corners' on the contours of constant distance from S?, and thereby yields a ``skeleton' of S. For unsegmented (gray level) pictures, one can use an analogous definition, in which local MIN and MAX operations play the roles of shrinking and expanding, to compute a ``MMMAT value' at each point of the picture. The set of points having high values defines a good ``skeleton' for the set of high-gray level points in the given picture.     

Performance consequences of two types of stereo picture compression

Two algorithms for stereo picture compression were evaluated. According to one algorithm, consistent with the fusion theory of depth perception, the reduction of information in the two pictures was about equal. The other algorithm, consistent with the suppression theory of depth perception, was based on very deep compression of one picture and minimal reduction of information in the second picture. Subjects performed depth decisions and object decisions on the compressed picture. They were able to perform both tasks on the compressed pictures, though performance generally was worse than in the un-compressed control conditions. In both tasks performance was better for an uneven division of information between the two pictures. These results are consistent with the suppression theory of depth perception.     

On the use of binary and gray code schemes for continuous-tone picture representation

The paper discusses the idea of iterating the conversion of a continuous-tone picture from binary to Gray code representation. A simple recursive function is defined by means of which the value of the ith bit representing a picture point's grey level after the mth iteration is determined. The resulting rearrangement of grey levels as well as that of the bits throughout the planes is discussed next. The iteration is shown to repeat after 2″ steps, where n is the number of bit planes representing the picture. A data compression scheme is developed on the basis that prior to exact repetition, approximate repetitions take place during the iterations, and the resulting picture is almost the same as the original.     

Image segmentation using a local extrema texture measure

An image segmentation technique is proposed which uses a texture measure that counts the number of local extrema in a window centered at each picture point. Four gray level pictures are derived, each of which represents a texture or gray level property of the original image. These intermediate pictures are used to derive the number of segments in which to divide the original image. The segmentation is then performed by assigning each pixel in the original image to a region by using a four-dimensional distance measure on the intermediate pictures, comparing each location to each selected segment. This process is then repeated in a hierarchical structure using decreasing window sizes so that smaller regions within the larger ones are defined. The computations required are amenable to real-time video implementation using state-of-the-art devices.     

Data reduction of picture signals: Review on the studies in Japan

Studies in Japan on data reduction of picture signals for a recent quater century are reviewed, which cover redundancy reduction coding in digital area and bandwidth compression in analogue area. Main issues are in the basic studies in early 70's and practical ones for new communication use in 80's.     

基于颜色特征和聚类的马氏距离图像分割法

给出了一种基于颜色特征和聚类的复杂彩图中进行目标图像分割的马氏距离算法.该方法利用目标的颜色进行图像分割.通过对彩图中的物体进行采样和分类,经过对每个像素点进行马氏距离计算和最小值寻找,将图像内的所有像素点进行归类,对目标图像与背景图像进行二值化分割,并对分类后含噪声的目标图像进行自适应滤波.设计了达到以上目的的人机交互式可视化计算机图像处理程序,对在水稻田中试验点上拍摄的水稻照片进行了分析处理,分离出了复杂背景下的水稻植株图像.实验结果表明,该算法能较好地解决复杂彩图中目标图像的分割问题.     

BMP图像的防伪数字水印

近年来,随着数字媒体的大量出现,数字水印作为一种信息安全技术越来越受到人们的关注。目前已经有许多BMP图像的数字水印算法,但是这些算法生成的数字水印图像很容易受到拷贝攻击,所谓拷贝攻击是指敌手将水印从一个作品拷贝到另一个作品的攻击方法。BMP图像的防伪数字水印算法把密码技术和数字水印技术结合起来,其生成的数字水印图像可以克服拷贝攻击。     

Tile rewriting grammars and picture languages

Tile rewriting grammars (TRG) are a new model for defining picture languages. A rewriting rule changes a homogeneous rectangular subpicture into an isometric one tiled with specified tiles. Derivation and language generation with TRG rules are similar to context-free grammars. A normal form and some closure properties are presented. We prove this model has greater generative capacity than the tiling systems of Giammarresi and Restivo and the grammars of Matz, another generalization of context-free string grammars to 2D. Examples are shown for pictures made by nested frames and spirals.     

H2+中波函数和电子云图形的绘制

在绘制势箱和氢原子体系波函数、电子云图形的基础上,进一步提出双原子分子一氢分子离子(H_2~ )波函数和电子云图形的绘制方法,结合图形从能量、波函数、电子云分布的角度,直观地说明了H_2~ 能够稳定成键的原因。     

A picture is worth a thousand words: A content analysis of Facebook profile photographs

This research examines identity construction and gender roles in social networking sites by studying and comparing the profile photographs of male and female Facebook users. Specifically, the number of photos in the profile album and the content of the main profile picture are studied by coding specific pictures, and determining if the content and amount of profile pictures differ significantly by gender. Participants include male and female Facebook users between the ages of 18 and 23 who are currently enrolled in a college or university. Profile pictures tended to be inactive, posed, appropriate, and only including the subject. The content and amount of Facebook profile photographs also did not significantly vary by gender. Implications of these findings, as well as suggestions for future research, are discussed.     

一种新的XML数据编码方案

如何对XML文档进行高效的查询,特别是包含查询处理,越来越受到研究界的关注。一种好的XML文档树编码方案可以很好地支持在XML文档上进行包含查询。为了加快XML数据的处理,利用完全二叉树的特性,提出了一种新的编码方案BTC。与区间编码和前缀编码相比,该编码具有简单和长度短的优点,实践证明该编码是有效的。     

一种低成本的视频数字图象获取方法在微计算机系统中的实现

本文阐述一种用二值影象组合装配获取视频数字图象的方法.按照这一方法,用标准电 视摄象机和八位微处理器实现了一个价廉而灵活的微计算机图象处理系统.文中给出了系统 视频图象输入接口结构框图及软件操作命令.该系统获取图象的最大能力为256×256,十六 灰度级;具有两种可以灵活选择的程序控制方式;以每灰度级40ms的速度输入局部图象,或 以每灰度级1800ms的速度(采用2MHz的8080A MPU)获取整幅图象.     

An effective method for still image compression/decompression for transmission on PSTN lines based on modifications of Huffman coding

This paper presents an effective compression method suitable for transmission the still images on public switching telephone networks (PSTN). Since compression algorithm reduce the number of pixels or the gray levels of a source picture, therefore this will lead to the reduction of the amount of memory needed to store the source information or the time necessary for transmitting by a channel with a limited bandwidth. First, we introduced some current standards and finally the lossy DCT-based JPEG compression method is chosen. According to our studies, this method is one of the suitable methods. However, it is not directly applicable for image transmission on usual telephone lines (PSTN). Therefore, it must be modified considerably to be suitable for our purposes. From Shannon’s Information Theory, we know that for a given information source like an image there is a coding technique which permits a source to be coded with an average code length as close as to the entropy of the source as desired. So, we have modified the Huffman coding technique and obtained a new optimized version of this coding, which has a high speed and is easily implemented. Then, we have applied the DCT¹ and the FDCT² for compression of the data. We have analyzed and written the programs in C++ for image compression/decompression, which give a very high compression ratio (50:1 or more) with an excellent SNR.³In this paper, we present the necessary modifications on Huffman coding algorithms and the results of simulations on typical images.