median_filter.m

各种滤波器

function y=median_filter(x,L)
%% median filter
% x : 输入数据,长度为N
% L : 中值滤波器的长度,必须为奇数 2K+1

%% Argument check
if mod(L,2)~=1
    error('Median Filter Length must be odd!');
end
N=length(x);
if L>=N
    error('Input data too short!');
end
K=(L-1)/2;

%% Filtering
y=zeros(size(x));
buffer=zeros(1,L);
for kk=1:K
    buffer=[zeros(1,K-kk+1),x(1:kk+K)];
    y(kk)=median(buffer);
end
for kk=K+1:N-K
    buffer=x(kk-K:kk+K);
    y(kk)=median(buffer);
end
for kk=N-K+1:N
    buffer=[x(kk-K:N),zeros(1,kk-N+K)];
    y(kk)=median(buffer);
end