www.gusucode.com > datafun 工具箱matlab源码程序 > datafun/movmedian.m
%MOVMEDIAN Moving median value. % Y = MOVMEDIAN(X,K) for a vector X and positive integer scalar K % computes a centered moving median by sliding a window of length K along % X. Each element of Y is the local median of the corresponding values of % X inside the window, with Y the same size as X. When K is even, the % window is centered about the current and previous elements of X. The % sliding window is truncated at the endpoints where there are fewer than % K elements from X to fill the window. % % For N-D arrays, MOVMEDIAN operates along the first array dimension % whose size does not equal 1. % % Y = MOVMEDIAN(X,[NB NF]) for a vector X and nonnegative integers NB and % NF computes a moving median along the length of X, returning the local % median of the previous NB elements, the current element, and the next % NF elements of X. % % Y = MOVMEDIAN(...,DIM) operates along dimension DIM of X. % % MOVMEDIAN(...,MISSING) specifies how NaN (Not-a-Number) values are % treated and can be one of the following: % % 'includenan' - (default) the median of any window containing NaN % values is also NaN. % 'omitnan' - the median of any window containing NaN values is % the median of all its non-NaN elements. If all % elements are NaN, the result is NaN. % % MOVMEDIAN(...,'Endpoints',ENDPT) controls how the median is calculated % at the endpoints of X, where there are not enough elements to fill the % window. ENDPT can be either a scalar numeric or logical value or one of % the following: % % 'shrink' - (default) compute the median over the number of % elements of X that are inside the window, effectively % reducing the window size to fit X at the endpoints. % 'fill' - compute the median over the full window size, filling % missing values from X with NaN. This is equivalent to % padding X with NaN at the endpoints. % 'discard' - compute the median only when the window is filled % with elements of X, discarding partial endpoint % calculations and their corresponding elements in Y. % This truncates the output; for a vector X and window % length K, Y has length LENGTH(X)-K+1. % % When ENDPT is a scalar numeric or logical value, the missing elements % of X inside the window are replaced with that value and Y remains the % same size as X. % % Example: Compute a 5-point centered moving median. % t = 1:10; % x = [4 8 6 -1 -2 -3 -1 3 4 5]; % yc = movmedian(x,5); % plot(t,x,t,yc); % % Example: Compute a 5-point trailing moving median. % t = 1:10; % x = [4 8 6 -1 -2 -3 -1 3 4 5]; % yt = movmedian(x,[4 0]); % plot(t,x,t,yt); % % Example: Compute a 5-point centered moving median, padding the ends of % the input with NaN. % t = 1:10; % x = [4 8 6 -1 -2 -3 -1 3 4 5]; % yp = movmedian(x,5,'Endpoints','fill'); % plot(t,x,t,yp); % % Example: Compute a 5-point trailing moving median, ignoring the first 4 % window shifts that do not contain 5 input elements. % x = [4 8 6 -1 -2 -3 -1 3 4 5]; % yd = movmedian(x,[4 0],'Endpoints','discard'); % % See also MEDIAN, MOVMEAN, MOVSTD, MOVVAR % % Copyright 2015 The MathWorks, Inc. % Built-in function.