remspike.m

王小平《遗传算法——理论、应用与软件实现》随书光盘

function a_filt=remspike(a,x)
%
%	REMSPIKE
%
%	Function to remove spikes in data sequence
%	held in an array x. The first and last points
%	of the sequence are unaltered.
%
%	Called: a_filt = remspike(tol,a)
%
%	a	=	array to be processed
%	tol	=	tolerance for spike removal
%	a_filt	=	array containing 'cleaned' values
%	x	=	multiple for tolerance setting
%
%	Calls: deltax
%
%	M.T. Tham (March 1996)
%

%	Set default tolerance to average absolute change in
%	signal

if nargin==1
	tol=mean(abs(deltax(a)));
else
	tol=x*(mean(abs(deltax(a))));
end;

novals=length(a);
delx=zeros([novals,1]);
a_filt=zeros([novals,1]);

%	Set up array of differenced values

delx=deltax(a);

%	First and last points in sequence are not
%	altered

a_filt(1)=a(1);a_filt(novals)=a(novals);

%	Now scan array of differenced values

for i=2:novals-1
	if abs(delx(i)+delx(i+1))<tol;
		a_filt(i)=(a(i-1)+a(i+1))*0.5;
	else
		a_filt(i)=a(i);
	end;
end;
a_filt=a_filt';
return