fx_deconv.m

著名的seismiclab的代码 是地震学研究人员必备的工具

function [DATA_f] = fx_deconv(DATA,lf,mu,flow,fhigh,dt,type);
%FX_DECONV: SNR enhancement using FX-AR modelling, also
%           known as  Canales' FX Deconvolution
%
%  [DATA_f] = fx_deconv(DATA,lf,mu,flow,fhigh,dt,itype)
% 
%  IN   DATA:   the data, columns are traces
%       lf:     lenght of the ar process (lenght of the filter)
%       flow:   min  freq. in the data in Hz
%       fhigh:  max  freq. in the data in Hz
%       dt:     sampling interval in sec
%       mu:     pre-whitening 
%       type:   Forward prediction type=1
%               Backward prediction type=-1
% 
%  OUT  DATA_f: filtered data
%       
%  SeismicLab
%  Version 1
%
%  written by M.D.Sacchi, last modified December 10, 1998.
%  [e-mail]
%
%  Copyright (C) 1998 Seismic Processing and Imaging Group
%                     Department of Physics
%                     The University of Alberta
%

[nt,ntraces] = size(DATA);

nf = 2^nextpow2(nt);
 
DATA_FX_f = zeros(nf,ntraces);

% Lower and Upper samples of the DFT.

ilow  = floor(flow*dt*nf)+1; if ilow<1; ilow=1;end;
ihigh = floor(fhigh*dt*nf)+1;if ihigh>floor(nf/2)+1; ihigh=floor(nf/2)+1;end

% Go into FX

DATA_FX = fft(DATA,nf,1);

for k=ilow:ihigh;
  aux_in  = DATA_FX(k,:)';
  aux_out = ar_f_b(aux_in,lf,mu,type);
  DATA_FX_f(k,:) = aux_out';
end;
  for k=nf/2+2:nf
  DATA_FX_f(k,:) = conj(DATA_FX_f(nf-k+2,:));
end

% Back to TX (the output) 

DATA_f = real(ifft(DATA_FX_f,[],1));
DATA_f = DATA_f(1:nt,:);

return