symlift.m

此为基于二代提升小波的阈值压缩算法源码

%**************************************************************************
% 函数功能：提供Symlets小波的提升方案
%**************************************************************************
function LS = SymLift(wname)

Num = wstr2num(wname(4:end));
switch Num
    %== sym2 ============================================================%
    case 2
        LS = {...
                'd',[-sqrt(3)],0; ...
                'p',[sqrt(3)-2 sqrt(3)]/4,1; ...
                'd',[1],-1 ...
            };
        LS(end+1,:) = {(sqrt(3)+1)/sqrt(2),(sqrt(3)-1)/sqrt(2),[]};
		
    case 3
		%--------------------  Num LS = 4  ----------------------% 
		LS = {...                                                                
		'd'                     [  0.4122865950085308]                      [0]  
		'p'                     [ -0.3523876576801823  1.5651362801993258]  [0]  
		'd'                     [ -0.4921518447467098 -0.0284590895616518]  [1]  
		'p'                     [  0.3896203901445617]                      [0]  
		[  0.5213212719156450]  [  1.9182029467652528]                      []   
		};                                                                              
  
    %== sym4 ============================================================%
    case 4
		%--------------------  Num LS = 16  ----------------------% 
		LS = {...                                                                
		'd'                     [  0.3911469419700402]                      [0]  
		'p'                     [ -0.1243902829333865 -0.3392439918649451]  [1]  
		'd'                     [ -1.4195148522334731  0.1620314520393038]  [0]  
		'p'                     [  0.4312834159749964  0.1459830772565225]  [0]  
		'd'                     [ -1.0492551980492930]                      [1]  
		[  1.5707000714496564]  [  0.6366587855802818]                      []   
		};                                                                       
   
    %== sym5 ============================================================%
    case 5
		%--------------------  Num LS = 29  ----------------------% 
		LS = {...                                                                
		'd'                     [ -0.9259329171294208]                      [0]  
		'p'                     [  0.4985231842281166  0.1319230270282341]  [0]  
		'd'                     [ -0.4293261204657586 -1.4521189244206130]  [1]  
		'p'                     [ -0.0948300395515551  0.2804023843755281]  [1]  
		'd'                     [  1.9589167118877153  0.7680659387165244]  [0]  
		'p'                     [ -0.1726400850543451]                      [0]  
		[  2.0348614718930915]  [  0.4914339446751972]                      []   
		};
   
    case 6
		%--------------------  Num LS = 1  ----------------------% 
		% Pow MAX = 0 - diff POW = 0
		%---+----+----+----+----+---%
		LS = {...                                                                 
		'd'                     [  0.2266091476053614]                      [0]   
		'p'                     [  1.2670686037583443 -0.2155407618197651]  [1]   
		'd'                     [ -0.5047757263881194  4.2551584226048398]  [-1]  
		'p'                     [ -0.0447459687134724 -0.2331599353469357]  [3]   
		'd'                     [ 18.3890008539693710 -6.6244572505007815]  [-3]  
		'p'                     [ -0.1443950619899142  0.0567684937266291]  [5]   
		'd'                     [  5.5119344180654508]                      [-5]  
		[ -1.6707087396895259]  [ -0.5985483742581210]                      []    
		};                                                                        

    case 7
		%--------------------  Num LS = 1  ----------------------% 
		% Pow MAX = 0 - diff POW = 0
		%---+----+----+----+----+---%
		LS = {...                                                                 
		'p'                     [  0.3905508237124110]                      [0]   
		'd'                     [ -0.3388639272262041  7.1808202373094066]  [0]   
		'p'                     [ -0.0139114610261505 -0.1372559452118446]  [2]   
		'd'                     [ 29.6887047769035310  0.1338899561610895]  [-2]  
		'p'                     [  0.1284625939282921 -0.0001068796412094]  [4]   
		'd'                     [ -7.4252008608107740 -2.3108058612546007]  [-4]  
		'p'                     [  0.0532700919298021  0.2886088139333021]  [6]   
		'd'                     [ -1.1987518309831993]                      [-6]  
		[  2.1423821239872392]  [  0.4667701381576485]                      []    
		};                                                                        

    case 8
		%--------------------  Num LS = 1  ----------------------% 
		% Pow MAX = 0 - diff POW = 0
		%---+----+----+----+----+---%
		LS = {...                                                                 
		'd'                     [  0.1602796165947262]                      [0]   
		'p'                     [  0.7102593464144563 -0.1562652322408773]  [1]   
		'd'                     [ -0.4881496179387070  1.8078532235524318]  [-1]  
		'p'                     [  1.7399180943774144 -0.4863315213006700]  [3]   
		'd'                     [ -0.5686365236759819 -0.2565755576271975]  [-3]  
		'p'                     [ -0.8355308510520870  3.7023086183759020]  [5]   
		'd'                     [  0.5881022226370752 -0.3717452749902822]  [-5]  
		'p'                     [ -2.1580699620177337  0.7491890598341392]  [7]   
		'd'                     [  0.3531271830147090]                      [-7]  
		[  0.4441986800900797]  [  2.2512448704197152]                      []    
		};                                                                        
        
    otherwise
        error('Invalid wavelet number.')
        
end