38 Abstract— Compression is a technology for reducing the quantity of data used to represent any content without excessively reducing the quality of the picture. The need for an efficient technique for compression of images ever increasing because the raw images need large amounts of disk space seems to be a big disadvantage during transmission & storage. Compression is a technique that makes s...

It is shown that the techniques of source coding (or "data compression") can be usefully applied in cryptography. Five source coding schemes (ShannonFano coding, Huffman coding, Lynch-Davisson coding, Elias-Willems coding, and Lempel-Ziv coding) are reviewed and their characteristics delineated. It is then shown how the last three of these schemes, which are of the universal source coding type,...

We provide a framework for registering automatic methods to derive class instances of datatypes, as it is possible using Haskell’s “deriving Ord, Show, . . . ” feature. We further implemented such automatic methods to derive (linear) orders or hash-functions which are required in the Isabelle Collection Framework [1] and the Container Framework [2]. Moreover, for the tactic of Huffman and Kraus...

In this paper, the comparative studies of Adaptive Region Based Huffman compression techniques are done. All these techniques use a region formation algorithm that is also discussed. This algorithm is used to form regions whose size is adjusted depending on the ASCII value difference of elements in the file. One of the techniques is Size Adaptive Region Based Huffman Compression (SARBH) where H...

In this article, the authors consider the following question about Huffman coding, which is an important technique for compressing data from a discrete source. If p is the smallest source probability, how long, in terms of p, can the longest Huffman codeword be? It is shown that if p is in the range 0 < p _< I/2, and if K is the unique index such that I/FI<+3 < p _< 1/FK+2, where FK denotes the...

Wedescribe Phrasal Rank-Encoding (PR-Enc), a novel method for the compression of wordaligned target language data in phrase tables as used in phrase-based SMT. This method reduces the redundancy in phrase tables which is a direct effect of the phrase-based approach. A combination of PR-Enc with Huffman coding allows to reduce the size of an aggressively compressed phrase table by another 39 per...

Data hiding, which embeds secret data into cover media, is one type of technology used to achieve the multimedia security. A reversible data hiding method has the characteristic that the cover media can be completely reconstructed after secret data are extracted. Recently, some reversible data hiding schemes have focused on the vector quantization (VQ)-compressed format. Using the modified fast...

The image data compression has been an active research area for image processing over the last decade [1] and has been used in a variety of applications. This paper investigates the implementation of Low Power VLSI architecture for image compression, which uses Variable Length Coding method to compress JPEG signals [1]. The architecture is proposed for the quantized DCT output [5]. The proposed...

Compression helps in reducing the redundancy in the data representation so as to reduce the storage requirement of it. Compression is an important technique used to improve web retrieval latency Compression is an important technique used to improve web retrieval latency. Plethora of algorithms is available for compressing the data. Some of the algorithms helps in achieving lossless compression ...

In this paper we present a statistical modeling for DCT events frequency distribution for three images classes: landscape, portrait and document. We show that it is possible to fit a mathematical model capturing the underlying statistical distribution. This modeling allows us to automatically generate optimized Huffman tables for each quality factor involved in the compression engine.