tpsgrid                package:shapes                R Documentation

_T_h_i_n-_p_l_a_t_e _s_p_l_i_n_e _t_r_a_n_s_f_o_r_m_a_t_i_o_n _g_r_i_d_s

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

     Thin-plate spline transformation grids from one planar object to
     another. A square grid on the first object is deformed smoothly
     using a pair of  thin-plate splines to a curved grid on the second
     object.

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

     tpsgrid(TT, YY, xbegin, ybegin, xwidth, opt, ext, ngrid)

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

      TT: First object (source): (k x 2 matrix)

      YY: Second object (target): (k x 2 matrix)

  xbegin: lowest x value for plot

  ybegin: lowest y value for plot

  xwidth: width of plot

     opt: Option 1: (just deformed grid on YY is displayed),  option 2:
          both grids are displayed

     ext: Amount that grid extends over object.

   ngrid: Number of grid points: size is ngrid * (ngrid -1)

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

     Note - only for $m=2$ planar objects

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

     No returned value

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

     Ian Dryden

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

     Bookstein, F.L. (1989). Principal  warps: thin-plate splines and 
     the decomposition  of  deformations, IEEE Transactions on Pattern
     Analysis and Machine Intelligence, 11, 567-585. 

     Dryden, I.L. and Mardia, K.V. (1998) Statistical Shape  Analysis.
     Wiley, Chichester. Chapter 10.

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

     procGPA

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

     data(gorf.dat)
     data(gorm.dat)

     #TPS grid with shape change exaggerated (2x)
     gorf<-procGPA(gorf.dat)
     gorm<-procGPA(gorm.dat)
     mag<-2
     TT<-gorf$mshape
     YY<-gorm$mshape
     par(mfrow=c(1,2))
     YY<-TT+(YY-TT)*mag
     tpsgrid(TT,YY,-0.6,-0.6,1.2,2,0.1,22) 
     title("TPS grid: Female mean (left) to Male mean (right)")   

