function H = act_H(h,k); if nargin==2 if strcmp(k,'all') H={}; for k=1:length(h) H{k} = act_H(h,k); end else im = h(k).im; H = h(k).H(im,1:h(k).ra); end else H=[]; for k=1:length(h) Hk = act_H(h,k); if k>1 & (size(H,2)