deconf.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,specinv]= deconf(trin,trdsign,n,stab,phase)

% [trout,specinv]=deconf(trin,trdsign,n,stab,phase)
% [trout,specinv]=deconf(trin,trdsign,n,stab)
% [trout,specinv]=deconf(trin,trdsign,n)
%
% DECONF performs a frequency domain deconvolution of the
% input trace
%
% trin= input trace to be deconvolved
% trdsign= input trace to be used for operator design
% n= number of points in frequency domain boxcar smoother
% stab= stabilization factor expressed as a fraction of the
%       zero lag of the autocorrelation. This is equivalent to being
%		a fraction of the mean power.
%      ********* default= .0001 **********
% phase= 0 ... zero phase whitening is performed
%        1 ... minimum phase deconvolution is performed
% ************** default= 1 ***************
%
% trout= output trace which is the deconvolution of trin
% specinv= output inverse operator spectrum. The time domain 
%          operator can be recovered by real(ifft(fftshift(specinv)))
%
% by: G.F. Margrave, May 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.
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% END TERMS OF USE LICENSE

% set defaults
  if nargin < 5
   phase=1;
  end
  if nargin<4
    stab=.0001;
  end
  
  % switch to row vectors
  [k,j]=size(trin);
  if(k==1) trin=trin.'; trdsign=trdsign.'; end
  
% pad input traces to power of 2
  N=length(trin); Nd=length(trdsign);
  trin=padpow2(trin);
  trdsign=pad(trdsign,trin);
  Npad=length(trin);
  %increase n to account for padding
  n = Npad*n/N;

% generate the power spectrum (pad to length of trin)
  %m=length(trin)-length(trdsign);
  spec= fftshift(fft(trdsign));
  power= real(spec).^2 + imag(spec).^2;
% stabilize the power spectrum
  mean_p= sum(power)/length(power);
  delta_p= stab*mean_p;
  power=power+delta_p;
% create frequency smoother (odd number of points)
  smoother=boxcar(2*fix(n/2)+1);
  power=convz(power,smoother);
% compute the minimum phase spectrum
  if phase==1
     logspec=hilbert(.5*log(power));
     % compute the complex spectrum of the inverse operator
     specinv= exp(-conj(logspec));
  else
     specinv=power.^(-.5);
  end
% deconvolve the input trace
  specin=fftshift(fft(trin));
  specout=specin.*specinv;
  trout=real(ifft(fftshift(specout)));
  trout=balans(trout,trin);
  
  %unpad to length of trin
  trout = pad(trout,N);
  
  if( k==1 ) trout =trout.'; end