restrict_ker.m

来自「采用matlab编写的数字图像恢复程序」· M 代码 · 共 24 行

  function kerH = ker_restrict(kerh,p)
%
%  kerH = ker_restrict(kerh)
%  kerH = ker_restrict(kerh,p)
%
%  Apply 2-D multilevel restriction based on piecewise constant 
%  heirarchical basis functions to the kernel of a 2-D convolution 
%  integral operator.
%
%  kerh is the kernel being restricted.
%  p is the number of levels of restriction.

  n2 = max(size(kerh));
  
  for level = 1:p
    n = n2 / 2;
    kerH = zeros(n,n);
    kerHx = zeros(n,n2);
    kerHx(2:n,:) = (kerh(2:2:n2-2,:)+2*kerh(3:2:n2-1,:)+kerh(4:2:n2,:)) / 4;
    kerH(:,2:n) = (kerHx(:,2:2:n2-2)+2*kerHx(:,3:2:n2-1)+kerHx(:,4:2:n2)) / 4;

    kerh = kerH;
    n2 = n;
  end