www.pudn.com > logtools.rar > hmask.m, change:2004-08-13,size:2765b


function [mask,htrin]=hmask(trin,thresh) 
 
% [mask,htrin]=hmask(trin,thresh) 
% [mask,htrin]=hmask(trin) 
% 
% Compute the Hilbert Reflectivity Mask of trin. 
% HMASK returns a trace which is zero everywhere except at the 
% samples corresponding to peaks of abs(hilbert(trin)) where it 
% is 1.0 
% 
% trin= input trace 
% mask= output hilbert mask trace 
% htrin= complex hilbert transform of trin. (e.g. hilbert(trin)) 
% thresh = threshold significance for peaks. Peaks on the Hilbert 
%	envelope are ignored if they are smaller than thresh times 
%	the maximum peak. 
%	********** default = .05 ********* 
%  
% by G.F. Margrave, July 1991 
% 
% 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 
 
% $Id: hmask.m,v 1.4 2004/07/30 22:03:45 kwhall Exp $ 
 
if(nargin<2) 
		thresh=.05; 
end 
 
% compute hilbert transform and envelope 
htrin=hilbert(trin).'; 
env=abs(htrin); 
% build hilbert mask 
iex=findex(env); 
 mask=zeros(size(env)); 
 if length(iex)>=1, 
  mask(iex)=ones(size(iex)); 
 end 
 mm=max(env); 
 iz=find(env<mm*thresh); 
 mask(iz)=zeros(size(iz));