Depth-first picture expression viewed from digital picture processing

A picture coding strategy titled DF-expression (Depth-First picture expression) is now studied from another point of view. The basic idea of DF-expression is briefly reviewed at first. Its capability in data compression is demonstrated using 1024 × 1024 binary pictures. Then the new aspects of DF-expression are studied in reference to picture processing algorithm on the coded form. They include circular shiftings, spectrum of primitives, logical operations, etc. Application of DF-expression to gray images (or multivalued pictures) is the next topics of the paper. DF-expression is applicable to bit-plane coding of any binary image data. Our conclusion with this point is that the gray code is the best binary code system for DF-expression in information preserving sense. Information-lossy type data reduction is another topics in this paper. The authors propose a new data reduction technique in terms of uniformalization of excessively complicated regions in bit-planes. Experimental study follows using a 256 × 256 sized fourbit test picture. Finally, conclusions and other possibility of the applications are remarked.     

模M多维差分变换和数据压缩

本文提出了模M多维差分变换的图象表示和压缩方法.变换是在对N维图象数组的2~N元分割所产生的2~N元树上进行,其效果是利用了图象的N维数据相关性,使得图象灰度值分布得到了显著的改善,它既适合于二值图象,也适合于多值图象,对于线图、文本以及具有块状或体状的图象或数组尤为有效,变换算法的复杂度非常简单,并且是递归可执行的。     

可交换上下文无关文法

本文提出了可交换上下文无关文法及其该文法产生的语言——可交换上下文无关语言，证明了正规语言类是可交换上下文无关语言类的一个子集，而可交换上下文无关语言类是上下文无关语言类的一个子集；讨论了可交换上下文无关语言的结构特点，并给出了可交换上下文无关语言的Pumping引理。     

A hybrid (visual/natural) controlled language

We define the notion of controlled hybrid language that allows information share and interaction between a controlled natural language (specified by a context-free grammar) and a controlled visual language (specified by a Symbol-Relation grammar). We present the controlled hybrid language INAUT, used to represent nautical charts of the French Naval and Hydrographic Service (SHOM) and their companion texts (Instructions nautiques).     

A CKY parser for picture grammars

We study the complexity of the membership or parsing problem for pictures generated by a family of picture grammars: Siromoney's Context-Free Kolam Array grammars (coincident with Matz's context-free picture grammars). We describe a new parsing algorithm, which extends the Cocke, Kasami and Younger's classical parsing technique for string languages and preserves the polynomial time complexity.     

基于二代小波视频编码算法的实现

传统的图像序列压缩算法采用的是基于DCT变换的变长编码算法,但传统的DCT算法以及量化过程带来不可避免的边缘效应和块效应.文中提出了基于第二代小波视频编码算法的完整模型,并且对此模型的可行性进行了分析和验证.文中的实验基于的是H.263的编码协议采用了二代小波(提升结构)变换,零型树编码,零数量化的方法.由PC机上的仿真实验结果显示此方法确实解决了前述的方块效应和边缘效应,同时满足了图像压缩率的问题和实时性要求.为将来在嵌入式平台上实现高质量的视频序列的实时传输提供了理论依据.     

On grammar forms with terminal context

Summary A context-free grammar form G defines a family of context-free grammars {ie397-01}(G). In this paper {ie397-02}(G) is extended to give the family of terminal context grammars {ie397-03}(G), which were introduced by Book [4]. It is shown that the families of languages defined by {ie397-04}(G) and {ie397-05}(G) are equal when G is an -free context-free grammar form. This generalizes the result of Book [4] for context-free grammars and underlines the usefulness of the notion of grammar forms in formal language theory.The work of the second author was carried out partially under a National Research Council of Canada Grant. No. A-7700 and partially under the auspices of the University of Karlsruhe     

一种基于二值化和亚采样的文本图像压缩方法

文中研究了彩色文本图像的高倍压缩方法。首先利用灰度窗口变换和整体阈值将原图二值化;然后进行亚采样处理并编码;在编码过程中,以经典的哈夫曼及游程编码为基础,设计了一种特殊的码流传输方式;最后用不同的插值方法近似的恢复了图像。实验结果证明,利用该方法当压缩比达到100倍以上时,恢复图像仍然具有高度的保真性。     

Data compression of digital color pictures

Reversible data compression of computer-generated digital color pictures is studied. The pictures are composed of three bilevel colors: magenta, yellow and cyan. False halftones are provided by a set of fixed raster matrices. The information content and upper limits on the compression ratio are obtained by calculating the picture entropy. Several compression algorithms of various complexity are investigated. A simple algorithm called “skip-on-equal” is shown to result in a compression ratio around six. More elaborate schemes, such as predictive coding and arithmetic coding, yield ratios around eleven. The compression methods studied depend on the size of the raster matrices, but are independent of the particular patterns used.     

H．264帧内编码与JPEG2000的性能比较与分析

为了给P帧和B帧作参考帧．保证编码序列在解码时能正确地开始和进行，H．264中的I帧编码是一种独立消除空间冗余度的适度图像压缩算法，没有使用帧间预测和补偿。在某种程度上，I帧编码可以被认为是一种静态图像编码。JPEG2000是ISO推出的新一代静态图像压缩标准。通过对目前这两种最先进的图像压缩标准的分析和比较，得出在较低的码率下，针对小尺度图像，H．264的帧内压缩有着比JPEG2000更好的性能，而在其他条件下JPEG2000的算法占优。     

一种黑白数字签名的水印技术研究

本文提出了基于小波变换实现黑白数字签名水印的一种方法。黑白的签名水印的应用范围很广泛,在对数字图像的认证中,简单的黑白二值水印就可以高效的达到鉴定的作用。在对黑白二值水印进行水印嵌入时,利用小波变换对原始宿主图像进行处理,对黑白签名水印进行二进制处理,同时对逼近子图做高斯滤波,与原逼近子图对比来确定水印嵌入位置。实验结果表明水印是不可见的,对JPEG有损压缩、中值滤波、噪声干扰等有较强的鲁棒性。     

Direction controlled programmed grammars

Summary A generalization of the notion of a context-free grammar is presented here. It is based on the notion of a programmed grammar. When the underlying context-free rules do not contain erasing, the class of languages obtained is identical with the class of context-sensitive languages. With underlying context-free rules containing erasing one obtains the class of recursively enumerable languages.The author is indebted to Drs. T. A. Zoethout for very useful discussions concerning this paper.     

Syntactic complexity of context-free grammars over word monoids

 The syntactic complexity of context-free grammars defined over word monoids is investigated. It is demonstrated that every recursively enumerable language can be defined by a ten-nonterminal context-free grammar over a word monoid generated by an alphabet and six words of length two. Open problems are formulated. Received October 10, 1994/February 23, 1995     

A Picture Archive Browser

We describe an implementation of a networked picture browser. The system offers a pictorial interface to pictorial data, relieves the users of thinking about the underlying filing system, provides managerial tools for installing, moving and deleting pictures, offers graded access and picture sharing and supports a number of picture formats, including hierarchical encodings.     

Symbolic Picture Languages and their Decidability and Complexity Properties

In this paper, some subclasses of Positional Grammars have been formalized as an extension of thepicture grammars which were introduced by Maurer, Rozenberg and Welzl. This allows us to exploit the theoretical background established for picture languages and context-free languages to get insight into the features of the Positional grammar model. In particular, we have focused on several decidability and complexity issues for the (drawn) symbolic picture languages and their striped versions.     

GPS数据的纯数字化协同压缩算法

对需实时传输的GPS(Global Position System)定位数据进行数据压缩,降低其数据传输量并最大限度地保留原GPS数据的完整性。依据GPS定位数据特性对其进行纯数字化无损预处理,引入Golomb-Rice算法并提出算法协同压缩思想。实验表明半字节编码与实时二进制算术编码协同压缩GPS数据最佳,该协同算法不仅满足GPS数据传输实时性,而且其压缩率在85%以上。本算法减少了GPS数据传输量,降低了流量成本;能适应多种类型的GPS定位数据压缩;无区域使用局限性,能够在全球任意国家中使用。     

A microprocessor-based still frame capturing system

This paper describes the design and implementation of a low cost image capturing system. The basic feature of the design is the massive reduction of the storage requirement in comparison with a fully buffered system. This has been accomplished by effecting a compromise between the amount of high speed storage and the time required to store all or part of a digitized frame, defined as 512 scan lines, each containing 512 picture elements in the format of eight-bit words. The system can be used for the transmission of pictures, texts or documents, where the need for storing pictorial data before transmission can be totally eliminated. It can also be employed as a low cost input technique for a digital image processing system where the required image can be stored in a computer memory and undergo various image processing operations.     

推导可交换上下文无关语言

提出了推导可交换上下文无关语言及其文法,证明了正规语言类和有界上下文无关语言类都是推导可交换上下文无关语言类的子集,而推导可交换上下文无关语言类是上下文无关语言类的一个子集;定义了该类语言的α闭包等有关运算,给出了推导可交换上下文无关语言表达式,证明了推导可交换上下文无关文法、推导可交换上下文无关语言表达式之间的等价转换.