peaks                package:PROcess                R Documentation

_P_e_a_k _D_e_t_e_c_t_i_o_n

_D_e_s_c_r_i_p_t_i_o_n:

     Finds the local maxima, local noise and its associated standard 
     deviations in a vector.

_U_s_a_g_e:

     peaks(x, span = 3)
     noise(x, span = 5)
     sigma(x, span = 5)

_A_r_g_u_m_e_n_t_s:

       x: a vector.

    span: a local miximum is defined as an element in a sequence which
          is greater than all other elements within a window of width
          `span' centered at that element. The default value is 3,
          meaning that a peak is bigger than both of its neighbors.
          Local noise is definedas an element minus the mean of all
          elements within a window of width `span' centered at that
          element. Local standard deviation of an element is defined as
          the standard deviation of all elements within a window of
          width `span' centered at that element.

_V_a_l_u_e:

     a logical vector of the same length as `series' indicating where
     the peaks are.

_A_u_t_h_o_r(_s):

     Xiaochun Li

_E_x_a_m_p_l_e_s:

     x <- seq(0, 10*pi, by=0.1)
     y <- sin(x)*x
     plot(x,y, type="l")
     is.max <- peaks(y)
     points(x[is.max],y[is.max], pch=21, bg="red")
     legend(2, 25, legend = "Peaks",pch = 19, col="red", bty = "n")

     # can be used for local minima too:
     # is.min <- peaks(-y)
     # points(x[is.min],y[is.min], pch=21, bg="blue")

