跪求快速中值滤波算法matlab源代码

function b = medfilt2(varargin)
%MEDFILT2 Perform 2-D median filtering.
% B = MEDFILT2(A,[M N]) performs median filtering of the matrix
% A in two dimensions. Each output pixel contains the median
% value in the M-by-N neighborhood around the corresponding
% pixel in the input image. MEDFILT2 pads the image with zeros
% on the edges, so the median values for the points within
% [M N]/2 of the edges may appear distorted.
%
% B = MEDFILT2(A) performs median filtering of the matrix A
% using the default 3-by-3 neighborhood.
%
% B = MEDFILT2(...,PADOPT) controls how the matrix boundaries
% are padded. PADOPT may be 'zeros' (the default),
% 'symmetric', or 'indexed'. If PADOPT is 'zeros', A is padded
% with zeros at the boundaries. If PADOPT is 'symmetric', A is
% symmetrically extended at the boundaries. If PADOPT is
% 'indexed', A is padded with ones if it is double; otherwise
% it is padded with zeros.
%
% Class Support
% -------------
% The input image A can be logical or numeric (unless the
% 'indexed' syntax is used, in which case A cannot be of class
% uint16). The output image B is of the same class as A.
%
% Remarks
% -------
% If the input image A is of integer class, all of the output
% values are returned as integers. If the number of
% pixels in the neighborhood (i.e., M*N) is even, some of the
% median values may not be integers. In these cases, the
% fractional parts are discarded. Logical input is treated
% similarly.
%
% Example
% -------
% I = imread('eight.tif');
% J = imnoise(I,'salt & pepper',0.02);
% K = medfilt2(J);
% imview(J), imview(K)
%
% See also FILTER2, ORDFILT2, WIENER2.
% Copyright 1993-2003 The MathWorks, Inc.
% $Revision: 5.18.4.6 $ $Date: 2003/08/23 05:53:02 $
[a, mn, padopt] = parse_inputs(varargin{:});
domain = ones(mn);
if (rem(prod(mn), 2) == 1)
order = (prod(mn)+1)/2;
b = ordfilt2(a, order, domain, padopt);
else
order1 = prod(mn)/2;
order2 = order1+1;
b = ordfilt2(a, order1, domain, padopt);
b2 = ordfilt2(a, order2, domain, padopt);
if islogical(b)
b = b | b2;
else
b = imlincomb(0.5, b, 0.5, b2);
end
end

%%%
%%% Function parse_inputs
%%%
function [a, mn, padopt] = parse_inputs(varargin)
checknargin(1,4,nargin,mfilename);
% There are several grandfathered syntaxes we have to catch
% and parse successfully, so we're going to use a strategy
% that's a little different that usual.
%
% First, scan the input argument list for strings. The
% string 'indexed', 'zeros', or 'symmetric' can appear basically
% anywhere after the first argument.
%
% Second, delete the strings from the argument list.
%
% The remaining argument list can be one of the following:
% MEDFILT2(A)
% MEDFILT2(A,[M N])
% MEDFILT2(A,[M N],[Mb Nb])
%
% Any syntax in which 'indexed' is followed by other arguments
% is grandfathered. Any syntax in which [Mb Nb] appears is
% grandfathered.
%
% -sle, March 1998
a = varargin{1};
charLocation = [];
for k = 2:nargin
if (ischar(varargin{k}))
charLocation = [charLocation k];
end
end
if (length(charLocation) > 1)
% More than one string in input list
eid = 'Images:medfilt2:tooManyStringInputs';
error(eid,'%s','Too many input string arguments.');
elseif isempty(charLocation)
% No string specified
padopt = 'zeros';
else
options = {'indexed', 'zeros', 'symmetric'};
padopt = checkstrs(varargin{charLocation}, options, mfilename, ...
'PADOPT', charLocation);

varargin(charLocation) = [];
end
if (strcmp(padopt, 'indexed'))
if (isa(a,'double'))
padopt = 'ones';
else
padopt = 'zeros';
end
end
if length(varargin) == 1,
mn = [3 3];% default
elseif length(varargin) >= 2,
mn = varargin{2}(:).';
if size(mn,2)~=2,
msg = 'MEDFILT2(A,[M N]): Second argument must consist of two integers.';
eid = 'Images:medfilt2:secondArgMustConsistOfTwoInts';
error(eid, msg);
elseif length(varargin) > 2,
msg = ['MEDFILT2(A,[M N],[Mb Nb],...) is an obsolete syntax. [Mb Nb]' ...
' argument is ignored.'];
wid = 'Images:medfilt2:obsoleteSyntax';
warning(wid, msg);
end
end
% The grandfathered [Mb Nb] argument, if present, is ignored.

自己看medfilt2的帮助

M = mean(A) %均值
M = median(A) %中值

查一下Matlab的Help就可以了。