log_datumadj.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 ylogout=log_datumadj(ylog,xlog,xd,yd,xdold,ydold)

% ylogout=log_datumadj(ylog,xlog,xd,yd,xdold,ydold)
% ylogout=log_datumadj(ylog,xlog,xd,yd)
%
% LOG_DATUMADJ performs datum adjustment on a log's vertical coordinates.
% The datum shift is accomplished
% by removing the old datum and installing the new one. The
% installation of a datum is done
% by subtracting the y coordinate of the datum at the logs x coordinate
% from the log's y coordinate vector.
% Datum removal is the opposite of datum installation.
% Datum shifts are rounded to the nearest whole sample (sample rate is 
%	taken to be ylog(2)-ylog(1) )
%
% ylog ... vector of y (vertical) coordinates for log
% xlog ... scalar giving the logs x coordinate
% (xd,yd) ... piecewise linear specification of the new datum
% (xdold,ydold) ... piecewise linear specification of the old
%		datum
%
% Default for the old datum is all zeros
% 
% 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.
%
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if(nargin< 5 )
	xdold=xd;
	ydold=zeros(size(xd));
end

	%compute the shifts
	%first the shifts to remove the old datum
	dy=ylog(2)-ylog(1);
	delyold=interpextrap(xdold,ydold,xlog,0);
	delyold=dy*round(delyold/dy);
	%now to install the new one
	dely=interpextrap(xd,yd,xlog,0);
	dely= dy*round( dely/dy );

	%combine the shifts
	dely=dely-delyold;

	ylogout=ylog-dely;