matlab图像专题;64 小波变换实现图像的方向性和边缘检测.zip

function [varargout] = wavefilter(wname,type) %wavefilter函数创建分解和重建滤波器 % [varargout] = wavefilter(wname,type)返回用于计算快速小波变 % 换和反变换的分解和\或重建滤波器 % % 例如： % [ld,hd,lr,hr] = wavefilter('haar') 获取‘Haar’小波的分解 % 高通和低通滤波器(ld,hd) % 及其重构高通和低通滤波器 % (lr,hr) % [ld,hd] = wavefilter('Haar','d') 获取分解滤波器(ld,hd) % [lr,hr] = wavefilter('Haar','r') 获取重构滤波器(ld,hd) % % INPUTS: % WNAME WAVELET NAME % -------------------------------------------------------- % 'Haar'or 'db1' Haar % 'db4' 4th order Daubechies % 'sym4' 4th order symlets % 'bior6.8' Cohen-Daubechies-Feauveau biorhogonal % 'jpeg9.7' Antonini-Barlaud-Mathieu-Daubechies % % TYPE FILTER TYPE % -------------------------------------------------------- % 'd' Decomposition filters % 'r' Reconstruction filters % % See also WAVEFAST and WAVEBACK. % Check the input and output arguments. error(nargchk(1,2,nargin)); if(nargin == 1 & nargout ~= 4)|(nargin == 2 & nargout ~= 2) error('输出变量的数量错误。') end if nargin == 1 & ~ischar(wname) error('WNAME必须是字符串') end if nargin == 2 & ~ischar(type) error('TYPE必须是字符串') end % 创建所需小波的滤波器 switch lower(wname) case{'haar','db1'} ld = [1 1]/sqrt(2); hd = [-1 1]/sqrt(2); lr = ld; hr = -hd; case 'db2' ld = [-0.1294 0.2241 0.8365 0.4830]; hd = [-0.4830 0.8365 -0.2241 -0.1294]; lr = [0.4830 0.8365 0.2241 -0.1294]; hr = [-0.1294 -0.2241 0.8365 -0.4830]; case 'db3' ld = [0.0352 -0.0854 -0.1350 0.4599 0.8069 0.3327]; hd = [-0.3327 0.8069 -0.4599 -0.1350 0.0854 0.0352]; lr = [0.3327 0.8069 0.4599 -0.1350 -0.0854 0.0352]; hr = [0.0352 0.0854 -0.1350 -0.4599 0.8069 -0.3327]; case'db4' ld = [-1.059740178499728e-002 3.288301166698295e-002 ... 3.084138183598697e-002 -1.870348117188811e-001 ... -2.798376941698385e-002 6.308807679295904e-001 ... 7.148465705525415e-001 2.303778133088552e-001]; t = (0:7); hd = ld; hd(end:-1:1) = cos(pi*t).*ld; lr = ld; lr(end:-1:1) = ld; hr = cos(pi*t).*ld; case 'coif1' ld = [-0.0157 -0.0727 0.3849 0.8526 0.3379 -0.0727]; hd = [0.0727 0.3379 -0.8526 0.3849 0.0727 -0.0157]; lr = [-0.0727 0.3379 0.8526 0.3849 -0.0727 -0.0157]; hr = [-0.0157 0.0727 0.3849 -0.8526 0.3379 0.0727]; case 'coif2' ld = [-0.0007 -0.0018 0.0056 0.0237 -0.0594 -0.0765... 0.4170 0.8127 0.3861 -0.0674 -0.0415 0.0164]; hd = [-0.0164 -0.0415 0.0674 0.3861 -0.8127 0.4170... 0.0765 -0.0594 -0.0237 0.0056 0.0018 -0.0007]; lr = [0.0164 -0.0415 -0.0674 0.3861 0.8127 0.4170... -0.0765 -0.0594 0.0237 0.0056 -0.0018 -0.0007]; hr = [-0.0007 0.0018 0.0056 -0.0237 -0.0594 0.0765 ... 0.4170 -0.8127 0.3861 0.0674 -0.0415 -0.0164 ]; case 'coif3' ld = [-0.0000 -0.0001 0.0005 0.0011 -0.0026 -0.0090... 0.0159 0.0346 -0.0823 -0.0718 0.4285 0.7938... 0.4052 -0.0611 -0.0658 0.0235 0.0078 -0.0038]; hd = [0.0038 0.0078 -0.0235 -0.0658 0.0611 0.4052... -0.7938 0.4285 0.0718 -0.0823 -0.0346 0.0159... 0.0090 -0.0026 -0.0011 0.0005 0.0001-0.0000]; lr = [-0.0038 0.0078 0.0235 -0.0658 -0.0611 0.4052... 0.7938 0.4285 -0.0718 -0.0823 0.0346 0.0159... -0.0090 -0.0026 0.0011 0.0005 -0.0001 -0.0000]; hr = [-0.0000 0.0001 0.0005 -0.0011 -0.0026 0.0090... 0.0159 -0.0346 -0.0823 0.0718 0.4285 -0.7938... 0.4052 0.0611 -0.0658 -0.0235 0.0078 0.0038]; case 'sym4' ld = [-7.576571478927333e-002 -2.963552764599851e-002 ... 4.976186676320155e-001 8.037387518059161e-001 ... 2.978577956052774e-001 -9.921954357684722e-002 ... -1.260396726203783e-002 3.222310060404270e-002]; t = (0:7); hd = ld; hd(end:-1:1) = cos(pi*t).*ld; lr = ld; lr(end:-1:1) = ld; hr = cos(pi*t).*ld; case'bior6.8' ld = [0 1.908831736481291e-003 -1.914286129088767e-003 ... -1.699063986760234e-002 1.193456527972926e-002 ... 4.973290349094079e-002 -7.726317316720414e-002 ... -9.405920349573646e-002 4.207962846098268e-001 ... 8.259229974584023e-001 4.207962846098268e-001 ... -9.405920349573646e-002 -7.7263173167204143e-002 ... 4.973290349094079e-002 1.193456527972926e-002 ... -1.699063986760234e-002 -1.914286129088767e-003 ... 1.908831736481291e-003]; hd = [0 0 0 1.442628250562444e-002 -1.446750489679015e-002 ... -7.872200106262882e-002 4.036797903033992e-002 ... 4.178491091502746e-001 -7.589077294536542e-001 ... 4.178491091502746e-001 4.036797903033992e-002 ... -7.872200106262882e-002 -1.446750489679015e-002 ... 1.442628250562444e-002 0 0 0]; t = (0:17); lr = cos(pi*(t+1)).*hd; hr = cos(pi*t).*ld; case'jpeg9.7' ld = [0 0.02674875741080976 -0.01686411844287495 ... -0.07822326652898785 0.2668641184428723 ... 0.6029490182363579 0.2668641184428723 ... -0.07822326652898785 -0.01686411844287495 ... 0.02674875741080976]; hd = [0 -0.09127176311424948 ... 0.05754352622849957 0.5912717631142470... -1.115087052456994 0.5912717631142470 ... 0.05754352622849957 -0.09127176311424948... 0 0]; t = (0:9); lr = cos(pi*(t+1)).*hd; hr = cos(pi*t).*ld; otherwise error('不能识别的小波名称（WNAME）。'); end % 输出所需滤波器 if(nargin == 1) varagout(1:4) = {ld,hd,lr,hr}; else switch lower(type(1)) case 'd' varargout = {ld,hd}; case 'r' varargout = {lr,hr}; otherwise error('不能识别的滤波器类型TYPE。'); end end