lp_lift.m

来自「基于MATLAB的图像压缩 能处理10:1的压缩功能 直接就能使用」· M 代码 · 共 20 行

function a = lp_lift(a,b,c)
% a(z) = a(z) + b(z) c(z^2)

d = zeros(1,length(c{1})*2-1);
d(1:2:end) = c{1};
d = conv(b{1},d);
z = b{2}+c{2}*2;
zmax = max(a{2},z);
f = [zeros(1,zmax-a{2}),a{1},zeros(1,a{2} - length(a{1}) - z + length(d))];
i = zmax-z + (1:length(d));
f(i) = f(i) + d;

if all(abs(f) < 1e-12)
   a = {0,0};
else
   i = find(abs(f)/max(abs(f)) > 1e-10);
   i1 = min(i);
   a = {f(i1:max(i)),zmax-i1+1};
end
return;