gusucode.com > DSISoft是由加拿大地质调查局发布的用于垂直地震剖面(VSP)数据处理的免费软件包 > dsisoftv3/main/seg2mat.m
function [matfile]=seg2mat(filename); %function [matfile]=seg2mat(filename) % %The funcion converts a SEG-2 formatted file into official DSI format %The filename must be specified within sigle quotation marks %The file identified by filename should contain all the SEG-2 to be processed %each on a separate line % %DSI customized VSP processing software %written by G. Perron 18/12/97 %$Id: seg2mat.m,v 3.0 2000/06/13 19:21:21 gilles Exp $ %$Log: seg2mat.m,v $ %Revision 3.0 2000/06/13 19:21:21 gilles %Release 3 % %Revision 2.0 1999/05/21 18:46:29 mah %Release 2 % %Revision 1.2 1999/01/14 20:17:01 perron %mofify lenght of read in string for sampling rate by 1 more character % %Revision 1.1 1999/01/06 19:09:08 kay %Initial revision % % %Copyright (C) 1998 Seismology and Electromagnetic Section/ %Continental Geosciences Division/Geological Survey of Canada % %This library is free software; you can redistribute it and/or %modify it under the terms of the GNU Library General Public %License as published by the Free Software Foundation; either %version 2 of the License, or (at your option) any later version. % %This library is distributed in the hope that it will be useful, %but WITHOUT ANY WARRANTY; without even the implied warranty of %MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU %Library General Public License for more details. % %You should have received a copy of the GNU Library General Public %License along with this library; if not, write to the %Free Software Foundation, Inc., 59 Temple Place - Suite 330, %Boston, MA 02111-1307, USA. % %DSI Consortium %Continental Geosciences Division %Geological Survey of Canada %615 Booth St. %Ottawa, Ontario %K1A 0E9 % %email: dsi@cg.nrcan.gc.ca filestr=readascii(filename); %looping over the list of files %opening the SEG-2 file for j=1:length(filestr) fid=fopen(filestr{j},'r','l'); chkseg2=fread(fid,4,'short'); %checking the file format if (dec2hex(chkseg2(1))~='3A55') disp('This file is not in SEG-2 format!') end size_tpsb=chkseg2(3); ntrc=chkseg2(4); %initializing the matfile trace headers matfile.th{j}=zeros(64,ntrc); %get the pointers to the top of each trace descriptor block fseek(fid,32,-1); tdb_tops=fread(fid,ntrc,'int'); %loop over traces for n=1:length(tdb_tops) fseek(fid,tdb_tops(n),-1); chktdb=fread(fid,2,'short'); if (dec2hex(chktdb(1))~='4422') disp('Unidentified Trace Descriptor Block!') end size_tdb=chktdb(2); %getting the number of samples fseek(fid,tdb_tops(n)+8,-1); nsmp=fread(fid,1,'int'); %getting the data format fseek(fid,tdb_tops(n)+12,-1); dataformat=fread(fid,1,'char'); %getting the channel number string fseek(fid,tdb_tops(n)+32,-1); descstr=fread(fid,size_tdb-32,'char')'; descstr=char(descstr); idxch=findstr(descstr,'CHANNEL_NUMBER'); %getting the sample interval string fseek(fid,tdb_tops(n)+32,-1); descstr=fread(fid,size_tdb-32,'char')'; descstr=char(descstr); idxsmp=findstr(descstr,'SAMPLE_INTERVAL'); %getting the channel number and sample interval values numchan=descstr(idxch+16:idxch+20); smp=descstr(idxsmp+16:idxsmp+22); smp=str2num(smp); %initializing the sequential trace number, ffid, number of traces and number of channels matfile.th{j}(1,n)=n; matfile.th{j}(2,n)=str2num(filestr{j}(5:8)); matfile.th{j}(12,n)=ntrc; matfile.th{j}(13,n)=str2num(numchan); %reading the data block if dataformat==1 fseek(fid,tdb_tops(n)+size_tdb,-1); matfile.dat{j}(:,n)=fread(fid,nsmp,'short'); elseif dataformat==2 fseek(fid,tdb_tops(n)+size_tdb,-1); matfile.dat{j}(:,n)=fread(fid,nsmp,'int'); elseif dataformat==4 fseek(fid,tdb_tops(n)+size_tdb,-1); matfile.dat{j}(:,n)=fread(fid,nsmp,'float'); elseif dataformat==5 fseek(fid,tdb_tops(n)+size_tdb,-1); matfile.dat{j}(:,n)=fread(fid,nsmp,'double'); end end %patching for the missing sample if length(0:smp:smp*nsmp)~=nsmp matfile.dat{j}(nsmp+1,:)=0; nsmp=nsmp+1; matfile.fh{10}=(nsmp-1)*smp; else matfile.fh{10}=nsmp*smp; end %closing the SEG-2 file fclose(fid); end %initializing the matfile file headers matfile.fh{1}=ntrc*length(filestr); matfile.fh{7}=nsmp; matfile.fh{8}=smp; matfile.fh{9}=0.0; matfile.fh{12}=length(filestr); matfile.fh{13}=ntrc;