www.pudn.com > logtools.rar > filttrinan.m, change:2004-08-13,size:3571b


function y = filttrinan(x,n)  % y = filttrinan(x,n) % % THIS IS BASICALLY A WEIGHTED MOVING AVERAGE OPERATOR % x is the input vector; the no.of pts. of the vector %    need not be specified % n is the number of points of the triangle smoother,  % y is the smoothed x, convolved with the %    triangle of n pts.  Because the added edges at %    the beginning and end are truncated, y will have %    the same number of points as x. %  T.N.Bishop, CCR, 4/94 %   %  FILTTRINAN DIFFERS FROM FILTTRI IN THAT IT HANDLES NaN's  %  FILTTRI will cause any trace portions containing NaN's to grow larger  %  by the length of the interpolation function.  %  FILTTRINAN avoids this by breaking the  %  input trace into live segments and interpolating each separately. %  The code is taken from Gary's SINCINAN function. %  % 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:  crewesinfo@crewes.org %  % 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. % % END TERMS OF USE LICENSE  % first find the live and dead zones 	ilive=find(~isnan(x)); 	ind=find(diff(ilive)>1); 	zone_beg=[ilive(1) ilive(ind+1)]; 	zone_end=[ilive(ind) ilive(length(ilive))]; 	nzones=length(zone_beg); %  %  compute the triangle function of n points n1 = fix(n/2)+1; box = ones(1,n1)/n1; f1 = conv(box,box); %  compute the center of the boxcar, assume n is odd nc = fix(n/2) + 1; %  compute other stuff npad = n; onepad = ones(1,npad); % % now initialize the output trace with nans, then loop over the zones % and interpolate traces that fall in them 	y=nan*ones(1,length(x)); 	 	for k=1:nzones 	                 xzone = x(zone_beg(k):zone_end(k));  		% get the input segment in this zone 		%pad input data with end values xpad = [xzone(1)*onepad xzone xzone(length(xzone))*onepad]; %  use Gary's fct from seis.toolbox, to get same no.of %  output points as input ypad = convz(xpad,f1,nc,length(xpad),0); 		% unpad output data with end values ypad = ypad((npad+1):(length(ypad)-npad));                  y(zone_beg(k):zone_end(k))=ypad(1:length(ypad));  	end