Design of One-dimensional and Two-dimensional Wavelet Filter Banks
Date Issued
2010
Date
2010
Author(s)
Shieh, Yi-Lin
Abstract
Traditionally, we use linear-phase FIR filter to design the one-dimensional or two-dimensional Quadrature Mirror filter banks(QMF). Although the phase distortion is completely eliminated; this structure has at least two disadvantages: first, it can’t eliminate the amplitude distortion completely, and second, it is hard to obtain a design with sharp band edges. To solve this problem, several papers propose to use the IIR allpass filters to construct an QMF. In this thesis, we will discuss the advantages of QMF constructed by the IIR allpass filters.
Filter design problems become a highly non-linear optimization problem in such a structure with IIR filters. Recently, several methods were proposed to design an QMF, and they consider the phase approximation for each allpass filter. However, this design scheme causes larger phase response error in the transition band. As a result, phase compensation is usually used to reduce the phase error with the price of the system delay increased.
In this paper, we mainly :
I. investigate the cause of phase error in transition band
II. solve it by proposing a new design method
III. show the advantage of using the method in simulation examples.
Besides, we propose a method to design two-dimensional QMF by using one-dimensional allpass filter. This method provides better results with less filter coefficients.
Subjects
multirate system
non-linear optimization problem
allpass filter
Quadrature Mirror Filter bank
orthonormal wavelet transform
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-99-R97942105-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):3b98c5c94791f8accd2bb3233eade930