Đang chuẩn bị nút TẢI XUỐNG, xin hãy chờ
Tải xuống
Đề án nâng là một công cụ hiệu quả để xây dựng thế hệ thứ hai sóng. Nó đã được sử dụng để thực hiện Daubechies wavelet biến đổi trong hình ảnh tiêu chuẩn nén JPEG-2000. Daubechies sóng có thể cung cấp hiệu suất tốt hơn hình ảnh mã hóa hơn so với biến đổi cosin rời rạc (DCT) được sử dụng trong JPEG bởi vì các sóng có thể đưa ra tín hiệu hiệu quả hơn so với DCT. | Science Technology Development Vol 11 No.09 - 2008 OPTIMAL LIFTING WAVELET FILTER BANK DESIGN AND IMAGE COMPRESSION APPLICATION Hoang Dinh Chien University of Technolog VNU-HCM Manuscript Received on March 06th 2008 Manuscript Revised May 06th 2008 ABSTRACT The lifting scheme is an efficient tool to construct second-generation wavelets. It has been used to realize Daubechies wavelet transform in image compression standard JPEG-2000. Daubechies wavelets can provide better image coding performance than discrete cosine transform DCT which is used in JPEG because the wavelets can present signal more efficiently than DCT. However for high compression rate the details of the decompressed images in JPEG-2000 are degraded. The reason is that Daubechies filters are maximally flat while their frequency selectivity is very poor. In this paper we present an efficient method for the optimal design of filter banks and wavelets based on the lifting structure. The design problem is expressed as an optimization problem where the frequency selectivity offilters is optimized for a given regularity order. The simulation results show that the filter banks designed by our proposed method can offer the coding performance improvement compared to Daubechies filters in JPEG-2000. Keywords Filter banks wavelets image coding regularity frequency selectivity global optimization. 1.INTRODUCTION The discrete wavelet transform DWT has found in various signal processing applications for example signal compression denoising watermarking and so on due to the fact that DWT can overcome the limitation of the traditional Fourier transform in being able to providing variable time and frequency resolutions 1 - 3 . As a result the DWT has been adopted in international multimedia compression standards such as JPEG-2000 and MPEG4 3 4 . In the DWT based applications proper choice of wavelets is critical to achieve systems with good performance. It is well-known that the wavelets can be generated by .
