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));