pad.m

基于matlab的反演程序,用于地球物理勘探中射线追踪及偏移成像程序.

function trout=pad(trin,trdsign,flag)

% trout=pad(trin,trdsign,flag)
%
% PAD pads (or truncates) trin to the same length as trdsign
%
% trin= input trace to be padded (truncated)
% trdsign= design trace to give desired length
%   if trdsign is a scalar, then it is assumed to give the desired
%   length.
% flag=0 the pad is added to the end of trin
%     =1 the pad is added such that the central sample of trin
%        stays in the middle.
% ***********default=0 *************
% trout= output trace
%
% by G.F. Margrave, June 1991
%
% NOTE: It is illegal for you to use this software for a purpose other
% than non-profit education or research UNLESS you are employed by a CREWES
% Project sponsor. By using this software, you are agreeing to the terms
% detailed in this software's Matlab source file.
 
% BEGIN TERMS OF USE LICENSE
%
% This SOFTWARE is maintained by the CREWES Project at the Department
% of Geology and Geophysics of the University of Calgary, Calgary,
% Alberta, Canada.  The copyright and ownership is jointly held by 
% its author (identified above) and the CREWES Project.  The CREWES 
% project may be contacted via email at:  [e-mail]
% 
% The term 'SOFTWARE' refers to the Matlab source code, translations to
% any other computer language, or object code
%
% Terms of use of this SOFTWARE
%
% 1) Use of this SOFTWARE by any for-profit commercial organization is
%    expressly forbidden unless said organization is a CREWES Project
%    Sponsor.
%
% 2) A CREWES Project sponsor may use this SOFTWARE under the terms of the 
%    CREWES Project Sponsorship agreement.
%
% 3) A student or employee of a non-profit educational institution may 
%    use this SOFTWARE subject to the following terms and conditions:
%    - this SOFTWARE is for teaching or research purposes only.
%    - this SOFTWARE may be distributed to other students or researchers 
%      provided that these license terms are included.
%    - reselling the SOFTWARE, or including it or any portion of it, in any
%      software that will be resold is expressly forbidden.
%    - transfering the SOFTWARE in any form to a commercial firm or any 
%      other for-profit organization is expressly forbidden.
%
% END TERMS OF USE LICENSE

 if nargin<3, flag=0; end
 [m,n]=size(trin);
 nout=length(trdsign);
 if(nout==1) nout = trdsign; end
if flag==0
 if n>m
   if nout>=n
     trout=[trin zeros(1,nout-n)];
   else
     trout=trin(1:nout);
   end
 else
   if nout>=m
     trout=[trin;zeros(nout-m,1)];
   else
     trout=trin(1:nout);
   end
 end
else
 if n>m
   if nout>=n
     npad=nout-n;
     nh=fix(npad/2);
     trout=[zeros(1,nh) trin zeros(1,npad-nh)];
   else
     ncut=n-nout;
     trout=trin(fix(ncut/2):fix(ncut/2)+nout-1);
   end
 else
   if nout>=m
     npad=nout-m;
     nh=fix(npad/2);
     trout=[zeros(nh,1);trin;zeros(npad-nh,1)];
   else
     ncut=nout-m;
     trout=trin(fix(ncut/2):fix(ncut/2)+nout-1);
   end
 end
end