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function [matfile]=bison2mat(filelist);
%function [matfile]=bison2mat(filelist)
%
%This function converts a BISON formatted file into official DSI format.
%
%INPUT
%filelist - Name of an ASCII file containing either a single collumn listing
%the names of the BISON files to be read into DSI format or else two columns
%where the first contains the file names and the second contains an number
%to be added to all of the channel numbers in that file (ex. for a survey
%where two recorders of 24 channels each were used for each shot, the
%channel numbers for one of the recorders could be incremented by 24 so that
%the data can easily be sorted by channel number. The name of the list file
%must be specified within sigle quotation marks. The channel number is
%stored in trace header word 1.
%
%OUTPUT
%matfile - data in DSI format
%
%DSI customized VSP processing software
%written by E.ADAM based on a C program provided by J. McGaughey
%$Id: bison2mat.m,v 3.0 2000/06/13 19:19:53 gilles Exp $
%$Log: bison2mat.m,v $
%Revision 3.0 2000/06/13 19:19:53 gilles
%Release 3
%
%Revision 2.0 1999/05/21 18:45:16 mah
%Release 2
%
%Revision 1.1 1999/01/06 19:09:02 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
disp('[matfile]=bison2mat(filelist)')
filestr=readascii(filelist);
%looping over the list of files
%opening the BISON file
for j=1:length(filestr)
temp=sscanf(filestr{j},'%s %d',[1,inf]);
if strcmp(class(temp),'char')
datafile=filestr{j};
channel_inc=0; %default is no channel increment
else
datafile=char(temp(1:length(temp)-1));
channel_inc=temp(length(temp));
end %if/else
fid=fopen(datafile,'r','l');
% Verify that this is a BISON FORMAT file
fseek(fid,117,-1);
chkbison=fgets(fid,7);
disp(['File format = ',chkbison]);
if (chkbison~='BISON-2');
disp('This file is not in BISON format!');
end
%get the FFID from the filename
ffid = char(filestr(j));
ffid = str2num(ffid(4:8));
% here I calculate the length of the header
fseek(fid,0,-1);
c = 0;
i= 0;
while c ~= 3,
c = fscanf(fid,'%c',1);
i = i+1;
if (c == 3)
c = fscanf(fid,'%c',1);
i = i+1;
end
end
header_length = i;
disp(['Header bytes read = ',num2str(i),' bytes']);
% Here I extract useful information from the header
fseek(fid,145,-1);
data_format=fgets(fid,1);
disp(['Data Format = ',data_format]);
fseek(fid,218,-1);
channels=str2num(fgets(fid,4));
disp(['Number of channels = ',num2str(channels)]);
fseek(fid,238,-1);
samples=str2num(fgets(fid,6));
disp(['Number of samples = ',num2str(samples)]);
fseek(fid,246,-1);
sample_rate=str2num(fgets(fid,4))/1000;
disp(['Sample rate = ',num2str(sample_rate)]);
%Allocate matfile matrices (to speed up code)
matfile.th{j}=zeros(64,channels);
matfile.dat{j}=zeros(samples,channels);
% Extract the data
for c = 1:channels,
offset=((samples/4)*10)*c+header_length;
fseek(fid,offset,-1);
for s = 1:(samples/4),
buff = fread(fid,4,'int16');
m1=buff(1);
m2=buff(2);
m3=buff(3);
m4=buff(4);
exps = fread(fid,1,'uint16');
e1=bitand(bitshift(exps,-12),15);
e2=bitand(bitshift(exps,-8),15);
e3=bitand(bitshift(exps,-4),15);
e4=bitand(exps,15);
f1=m1*2^(15-e1);
f2=m2*2^(15-e2);
f3=m3*2^(15-e3);
f4=m4*2^(15-e4);
signalf((s-1)*4+1)=f1;
signalf((s-1)*4+2)=f2;
signalf((s-1)*4+3)=f3;
signalf((s-1)*4+4)=f4;
end
% disp(['Extracting channel = ',num2str(c)])
%initializing the sequential trace number, ffid, number of traces and number of channels
matfile.th{j}(1,c)=c+channel_inc;
matfile.th{j}(2,c)=ffid;
matfile.th{j}(12,c)=channels;
matfile.th{j}(13,c)=c;
%writing the data block
matfile.dat{j}(:,c)=signalf;
end
%patching for the missing sample
if length(0:sample_rate:sample_rate*samples)~= samples
matfile.dat{j}(samples+1,:)=0;
samples=samples+1;
matfile.fh{10}=(samples-1)*sample_rate;
else
matfile.fh{10}=samples*sample_rate;
end
%closing the BISON file
fclose(fid);
end
%initializing the matfile file headers
matfile.fh{13}=channels;
matfile.fh{1}=channels*length(filestr);
matfile.fh{7}=samples;
matfile.fh{8}=sample_rate;
matfile.fh{9}=0.0;
matfile.fh{10}=sample_rate*(samples-1);
matfile.fh{12}=length(filestr);