tailieunhanh - Báo cáo hóa học: " Research Article On a Class of Parametric Transforms and Its Application to Image Compression"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article On a Class of Parametric Transforms and Its Application to Image Compression | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2007 Article ID 58416 14 pages doi 2007 58416 Research Article On a Class of Parametric Transforms and Its Application to Image Compression Susanna Minasyan 1 Jaakko Astola 1 and David Guevorkian2 1 Institute of Signal Processing Tampere University of Technology TUT . Box 527 33101 Tampere Finland 2Nokia Research Center . Box 100 33721 Tampere Finland Received 14 July 2006 Revised 29 January 2007 Accepted 27 April 2007 Recommended by Mauro Barni 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 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. Copyright 2007 Susanna Minasyan et al. This is an open access article distributed