[R] How can I represent a shape using 1-D discrete wavelet descriptor s?

[qin.li]

I only concern about the boundary of the shape and I don¡¯t concern gray
level. 
U[m] = x[m] + jy[m] m= 0,1,¡­,N-1 is the N points on the boundary.
It is easy to express U as a discrete Fourier series. 
But it seems like that wd in the wavethresh package cannot deal with complex
values.
And it is not interesting to transfer U to a matrix.
Thanks a lot

Qin