On a Class of Parametric Transforms and Its Application to Image Compression

Autor: Guevorkian David, Minasyan Susanna, Astola Jaakko
Jazyk: angličtina
Rok vydání: 2007
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Zdroj: EURASIP Journal on Advances in Signal Processing, Vol 2007, Iss 1, p 058416 (2007)
Druh dokumentu: article
ISSN: 1687-6172
1687-6180
Popis: A class of parametric transforms that are based on unified representation of transform matrices in the form of sparse matrix products is described. Different families of transforms are defined within the introduced class. All transforms of one family can be computed with fast algorithms similar in structure to each other. In particular, the family of Haar-like transforms consists of discrete orthogonal transforms of arbitrary order such that they all may be computed with a fast algorithm that is in structure similar to classical fast Haar transform. A method for parameter selection is proposed that allows synthesizing specific transforms with matrices containing predefined row(s). The potential of the proposed class of Haar-like parametric transforms to improve the performance of fixed block transforms in image compression is investigated. With this purpose, two image compression schemes are proposed where a number of Haar-like transforms are synthesized each adapted to a certain set of blocks within an image.The nature of the proposed schemes is such that their performance (in terms of PSNR versus compression ratio) cannot be worse than a scheme based on classical discrete cosine transform (DCT). Simulations show that a significant performance improvement can be achieved for certain types of images such as medical X-ray images and compound images.
Databáze: Directory of Open Access Journals
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