Survey of Hybrid Image Compression Techniques

A compression process is to reduce or compress the size of data while maintaining the quality of information contained therein. This paper presents a survey of research papers discussing improvement of various hybrid compression techniques during the last decade. A hybrid compression technique is a technique combining excellent properties of each group of methods as is performed in JPEG compression method. This technique combines lossy and lossless compression method to obtain a high-quality compression ratio while maintaining the quality of the reconstructed image. Lossy compression technique produces a relatively high compression ratio, whereas lossless compression brings about high-quality data reconstruction as the data can later be decompressed with the same results as before the compression. Discussions of the knowledge of and issues about the ongoing hybrid compression technique development indicate the possibility of conducting further researches to improve the performance of image compression method

Compression Technique Using DCT & Fractal Compression: A Survey

Steganography differs from digital watermarking because both the information and the very existence of the information are hidden. In the beginning, the fractal image compression method is used to compress the secret image, and then we encrypt this compressed data by DES.The Existing Steganographic approaches are unable to handle the Subterfuge attack i.e, they cannot deal with the opponents not only detects a message ,but also render it useless, or even worse, modify it to opponent favor. The advantage of BCBS is the decoding can be operated without access to the cover image and it also detects if the message has been tampered without using any extra error correction. To improve the imperceptibility of the BCBS, DCT is used in combination to transfer stego-image from spatial domain to the frequency domain. The hiding capacity of the information is improved by introducing Fractal Compression and the security is enhanced using by encrypting stego-image using DES.  Copyright © www.iiste.org Keywords: Steganography, data hiding, fractal image compression, DCT

Enhanced SVD Based Image Compression Technique

With the growth of technology and entrance into the Digital World, it has found itself surrounded by a massive quantity of data. Dealing with such huge data/information will often creates difficulties while transmission of data or storage of data. One feasible solution to overcome such difficulties is to use a data compression technique. Image compression is a method in which the storage space or processing space of image is reduced without degrading the image standard or quality. It conjointly reduces the time needed for images to be uploaded over the Internet or downloaded from Internet. JPEG is a necessary technique used for image compression. So, in order to improve the quality of the image, compression is done using different techniques. In this research work, SVD algorithm is used for compression which is giving better result for image compression without any reduction in quality. The modeling of optimized Singular Value Decomposition (SVD) implemented for JPEG Image compression in MATLAB is implemented. SVD is the core part of the JPEG image compression. In JPEG Image Compression, a quantizer follows the SVD. Such structural channel is beneficial for reducing difficulty in the whole JPEG compression/encoding. To overcome the problem of  lossy compression implemented algorithm is designed in order to enhance the performance of compression algorithm with respect to performance evaluation parameters such as, Compression ratio , Bits per pixel , Peak signal to noise ratio, Mean squared error  and Signal to noise ratio