Dilation operation on vector

[Terry Duell]

Hello All,
I have a vector, the elements of which are equally spaced profile  
elevations, i.e. a longitudinal section.
I wish to roll a rigid wheel (disc) of specified radius along this profile  
and obtain the locus of the centre of the disc, i.e. an attenuated profile  
vector.
As I understand it, this is essentially a dilation operation.
Does any one know of any functions available in Octave, or Octave Forge,  
that could do this?

Cheers,
--
Regards,
Terry Duell