biorlift.m

此为基于二代提升小波的阈值压缩算法源码

%**************************************************************************
% 函数功能：计算双正交样条小波的提升方案
% *************************************************************************
function LS = BiorLift(wname)

kdot = find(wname=='.');
if length(kdot)~=1 , error('*'); end
lw = length(wname);
Nd = wstr2num(wname(kdot+1:lw));
wname = wname(1:kdot-1);
lw = length(wname);
ab = abs(wname);
ii = lw+1;
while (ii>1) & (47<ab(ii-1)) & (ab(ii-1)<58), ii = ii-1; end
Nr = wstr2num(wname(ii:lw));

% 参数检查
if isempty(find(Nr == [1:6])) 
    error('Invalid wavelet number.')
end
errNAME = false;
switch Nr
  case 1 , if isempty(find(Nd == [1:2:5])) , errNAME = true; end
  case 2 , if isempty(find(Nd == [2:2:8])) , errNAME = true; end
  case 3 , if isempty(find(Nd == [1:2:9])) , errNAME = true; end
  case 4 , if Nd ~= 4 , errNAME = true; end
  case 5 , if Nd ~= 5 , errNAME = true; end
  case 6 , if Nd ~= 8 , errNAME = true; end      
end
if errNAME
    error('Invalid wavelet number.')
end

% 对应的提升方案
switch Nr
  case 1
    LS = {'d',[-1],0};
    switch Nd
      case 1 , LS(2,:) = {'p',[1/2],0};
      case 3 , LS(2,:) = {'p',[-1 8 1]/16,1};
      case 5 , LS(2,:) = {'p',[3 -22 128 22 -3]/256,2};
    end
    LS(3,:) = {sqrt(2),sqrt(2)/2,[]};   

  case 2
    LS = {'d',[-1 -1]/2,1};
    switch Nd
      case 2 , LS(2,:) = {'p',[1 1]/4,0};
      case 4 , LS(2,:) = {'p',[-3 19 19 -3]/64,1};
      case 6 , LS(2,:) = {'p',[5 -39 162 162 -39 5]/512,2};
      case 8 , LS(2,:) = {'p',[-35  335  -1563  5359  5359  -1563  335  -35]/16384 ,3}; 
    end
    LS(3,:) = {sqrt(2),sqrt(2)/2,[]};

  case 3
    LS = {'p',[-1/3],-1;'d',[-3 -9]/8,1};
    switch Nd
      case 1 , LS(3,:) = {'p',[4/9],0};
      case 3 , LS(3,:) = {'p',[-3 16 3]/36,1};
      case 5 , LS(3,:) = {'p',[5 -34 128 34 -5]/288,2};
      case 7 , LS(3,:) = {'d'  [-35/9216  25/768  -421/3072  -4/9  421/3072  -25/768  35/9216]  [4]}; 
      case 9 , LS(3,:) = {'d'  [7/8192  -185/20729  547/12288  -938/6295  -4/9  938/6295  -547/12288  185/20729  -7/8192]  [5]};
    end
    LS(4,:) = {3*sqrt(2)/2,sqrt(2)/3,[]};

  case 4
	LS = {...                                                                
	'd'                     [ -1.5861343420693648 -1.5861343420693648]  [1]  
	'p'                     [  1.0796367753628087 -0.0529801185718856]  [0]  
	'd'                     [ -0.8829110755411875 -0.8829110755411875]  [0]  
	'p'                     [  0.4435068520511142  1.5761237461483639]  [2]  
	[ -1.1496043988602418]  [ -0.8698644516247808]                      []   
	};                                                                       

  case 5
	LS = {...                                                                 
	'd'                     [  4.9932745216378791  4.9932745216378791]  [1]   
	'p'                     [ -0.1833932736462213 -0.0043674455906250]  [0]   
	'd'                     [  5.5857862011365809  5.5857862011365809]  [0]   
	'p'                     [ -3.0949380770116637  0.1732056148062267]  [2]   
	'd'                     [  0.2900930732401870  0.2900930732401881]  [-2]  
	'p'                     [ -3.4471695202783086]                      [3]   
	[  0.9249619350590361]  [  1.0811255707902991]                      []    
	};                                                                        
    
   case 6
	LS = {...                                                                                                         
	'p'                     [ -2.6589963611977199  0.9971506910514433]                                          [0]   
	'd'                     [  0.2735119746851613  0.2735119746851613]                                          [0]   
	'p'                     [  3.8778221455598287 -3.2686866117960300]                                          [2]   
	'd'                     [ -0.2865032579680539 -0.2865032579680544]                                          [-2]  
	'p'                     [ -0.5485941682554034  2.9417675368512870]                                          [4]   
	'd'                     [  0.0998232169757517 -0.3438132627628235 -0.3438132627531770  0.0998232170102641]  [-2]  
	[  0.8685786973079247]  [  1.1513061546402219]                                                              []    
	};    
end