Thread Subject: registration of two point clouds

Hello, I don't know where to start. The Problem: I have two different point clouds (x,y,z Coordinates of the head surface; one modell and one real data from a real head). I need to align these two. The real head data have to be rotated, streched, compressed or moved to fit in the modell. It is like a nonrigid registration for volumes - but it is no volume...

Has anyone ideas how to start? I calculated hulls (with crust algorithm) for both but don't know what to do with them. Thanks in advance!

"Christina " <christina.habermehl@gmx.de> wrote in message <h4kahu$qks$1@fred.mathworks.com>...
> Hello, I don't know where to start. The Problem: I have two different point clouds (x,y,z Coordinates of the head surface; one modell and one real data from a real head). I need to align these two. The real head data have to be rotated, streched, compressed or moved to fit in the modell. It is like a nonrigid registration for volumes - but it is no volume...
>
> Has anyone ideas how to start? I calculated hulls (with crust algorithm) for both but don't know what to do with them. Thanks in advance!

You could start with Horn's method:

http://mesh.caltech.edu/ee148/refs/Horn-etal-mitXX.pdf

It's a very old, but effective method. If you Google "absolute orientation", you will also be able to find a lot of follow up work and similar algorithms.

>
> You could start with Horn's method:
>
> http://mesh.caltech.edu/ee148/refs/Horn-etal-mitXX.pdf
>
> It's a very old, but effective method. If you Google "absolute orientation", you will also be able to find a lot of follow up work and similar algorithms.



Thank you, that looks like a good idea!