medfilt1               package:signal               R Documentation

_M_e_d_i_a_n _f_i_l_t_e_r

_D_e_s_c_r_i_p_t_i_o_n:

     Performs an n-point running median. For Matlab/Octave
     compatibility.

_U_s_a_g_e:

     medfilt1(x, n = 3, ...)

     MedianFilter(n = 3)

     ## S3 method for class 'MedianFilter':
     filter(filt, x, ...)

_A_r_g_u_m_e_n_t_s:

       x: signal to be filtered. 

       n: size of window on which to perform the median.  

    filt: filter to apply to the signal. 

     ...: additional arguments passed to 'runmed'. 

_D_e_t_a_i_l_s:

     'medfilt1' is a wrapper for 'runmed'.

_V_a_l_u_e:

     For 'medfilt1', the filtered signal of 'length(x)'.

     For 'MedianFilter', a class of "MedianFilter" that can be used
     with 'filter' to apply a median filter to a signal.

_A_u_t_h_o_r(_s):

     Tom Short.

_R_e_f_e_r_e_n_c_e_s:

     <URL: http://en.wikipedia.org/wiki/Median_filter>

     Octave Forge <URL: http://octave.sf.net>

_S_e_e _A_l_s_o:

     'runmed', 'median', 'filter'

_E_x_a_m_p_l_e_s:

     t = seq(0, 1, len=100)                           # 1 second sample
     x = sin(2*pi*t*2.3) + 0.25*rlnorm(length(t),.5)  # 2.3 Hz sinusoid+noise
     plot(t, x, type = "l")
     # 3-point filter
     lines(t, medfilt1(x), col="red", lwd=2) 
     # 7-point filter
     lines(t, filter(MedianFilter(7), x), col = "blue", lwd=2) # another way to call it

