slwt53.m

function coef=slwt53(frame,level)
%slwt53    Lifting 53 wavelet transform
%
%
%  Example:
%
%    coef=slwt53(frame);
%
%    frame(height, width)
%
%  -----------------------------------------------------------------
%  slwt53.m                                Minoru Hiki.     06/06/13

[height width]=size(frame);

for i=1:level
  hb=ceil(height/2^(i-1));
  wb=ceil(width/2^(i-1));
  frame(1:hb,1:wb)=trx(frame(1:hb,1:wb));
end
  coef=frame;		
  
  
function coef=trx(frame)
  [height width]=size(frame);

frame = double(frame);

  % horizontal
  if rem(width,2)==0
    % predict
    frame(:,2:2:width-2)=frame(:,2:2:width-2)-...
      floor((frame(:,1:2:width-3)+frame(:,3:2:width-1))/2);
    frame(:,width)=frame(:,width)-frame(:,width-1);
  
    % update
    frame(:,1)=frame(:,1)+floor((frame(:,2)+1)/2);
    frame(:,3:2:width-1)=frame(:,3:2:width-1)+...
        floor((frame(:,2:2:width-2)+frame(:,4:2:width)+2)/4);
  else
    % predict
    frame(:,2:2:width-1)=frame(:,2:2:width-1)-...
        floor((frame(:,1:2:width-2)+frame(:,3:2:width))/2);
    % update
    frame(:,1)=frame(:,1)+floor((frame(:,2)+1)/2);
    frame(:,3:2:width-2)=frame(:,3:2:width-2)+...
        floor((frame(:,2:2:width-3)+frame(:,4:2:width-1)+2)/4);
    frame(:,width)=frame(:,width)+...
        floor((frame(:,width-1)+1)/2);
end
  
  % vertical
  if(rem(height,2)==0)
    % predict
    frame(2:2:height-2,:)=frame(2:2:height-2,:)-...
        floor((frame(1:2:height-3,:)+frame(3:2:height-1,:))/2);
    frame(height,:)=frame(height,:)-frame(height-1,:);
    % update
    frame(1,:)=frame(1,:)+floor((frame(2,:)+1)/2);
    frame(3:2:height-1,:)=frame(3:2:height-1,:)+...
        floor((frame(2:2:height-2,:)+frame(4:2:height,:)+2)/4);
  else
    % predict
    frame(2:2:height-1,:)=frame(2:2:height-1,:)-...
        floor((frame(1:2:height-2,:)+frame(3:2:height,:))/2);
    % update
    frame(1,:)=frame(1,:)+floor((frame(2,:)+1)/2);
    frame(3:2:height-2,:)=frame(3:2:height-2,:)+...
        floor((frame(2:2:height-3,:)+frame(4:2:height-1,:)+2)/4);
    frame(height,:)=frame(height,:)+...
        floor((frame(height-1,:)+1)/2);
  end
  
  hb=round(height/2);
  wb=round(width/2);
  
  coef(1:hb,1:wb)=frame(1:2:height,1:2:width);
  coef(1:hb,wb+1:width)=frame(1:2:height,2:2:width);
  coef(hb+1:height,1:wb)=frame(2:2:height,1:2:width);
  coef(hb+1:height,wb+1:width)=frame(2:2:height,2:2:width);