A new secret writing using DES and DEFLATE algorithm is explored by improving the previous attempts in this sense in terms of security and compression. A Matching Pursuit algorithm using redundant basis decomposition technique is used to securely hide a message. The stability and computational complexity problems are solved by introducing new selection and update rules working entirely in the i...

Given a color image that was quantized in some hidden color space (termed compression color space) during previous JPEG compression, we aim to estimate this unknown compression color space from the image. This knowledge is potentially useful for color image enhancement and JPEG re-compression. JPEG quantizes the discrete cosine transform (DCT) coefficients of each color plane independently duri...

The fractal image compression problem put forward three major requirements: speeding up the compression algorithm, improving image quality or increasing compression ratio. Major variants of the standard algorithm were proposed to speed up computation time. But most of them lead to a bad image quality, or a lower compression ratio. In this paper we present an implementation based on genetic algo...

Given a color image that was quantized in some hidden color space (termed compression color space) during previous JPEG compression, we aim to estimate this unknown compression color space from the image. This knowledge is potentially useful for color image enhancement and JPEG re-compression. JPEG quantizes the discrete cosine transform (DCT) coefficients of each color plane independently duri...

It has been demonstrated with recent software implementations of context modeling the capability of PPM (Prediction by Partial Matching) [1] type of algorithms to achieve very high compression rates. However, the cost is high in terms of computational complexity and low speed. Hardware implementations of compression algorithms are capable of increasing compression speed by at least an order of ...

Due to bandwidth constraints on the wireless link in an IP network, it is useful to compress the headers so as to maximize the utilization of the link. Different Header Compression schemes have been proposed. Some make use of the similarity in consecutive headers in a packet flow to compress these headers. These are called here time compression, as they acquire the compression information over ...

The basis for the JPEG algorithm is the Discrete Cosine Transform (DCT) which extracts spatial frequency information from the spatial amplitude samples. These frequency components are then quantized to eliminate the visual data from the image that is least perceptually apparent, thereby reducing the amount of information that must be stored. The redundant properties of the quantized frequency s...

Statistical coding techniques have been used for a long time in lossless data compression, using methods such as Huffmans algorithm, arithmetic coding, Shannon’s method, Fano’s method, etc. Most of these methods can be implemented either statically or adaptively. In this paper, we show that although Fano coding is sub-optimal, it is possible to generate static Fano-based encoding schemes which ...

The medical image processing process is one of the most important areas of research in medical applications in digitized medical information. A medical images have a large sizes. Since the coming of digital medical information, the important challenge is to care for the conduction and requirements of huge data, including medical images. Compression is considered as one of the necessary algorith...