-------- Original Message --------
Subject: RE: TPS 3D negative bending energy
Date: Mon, 7 Feb 2011 23:07:33 -0500
From: F. James Rohlf <[email protected]>
Reply-To: [email protected]
Organization: Stony Brook University
To: [email protected]
It is the same minus sign whether put inside (as in Bookstein (1991) or
placed outside (as in Gunz et al. (2005)) the expression for bending
energy. Neither publication gives a derivation. Perhaps Bookstein will
join this thread and supply one.
----------------------
F. James Rohlf, John S. Toll Professor
Dept. Ecology and Evolution, Stony Brook University, NY 11794-5245
Please consider the environment before printing this email
-----Original Message-----
From: morphmet [mailto:[email protected]]
Sent: Monday, February 07, 2011 8:03 AM
To: morphmet
Subject: Re: TPS 3D negative bending energy
-------- Original Message --------
Subject: Re: TPS 3D negative bending energy
Date: Mon, 7 Feb 2011 05:56:43 -0500
From: Stefan Schlager <[email protected]>
To: [email protected]
but hen again, in the article /Gunz, P.; Mitteroecker, P. & Bookstein, F. 2005.
Semilandmarks in three dimensions. In: Slice, D. (Ed.), Modern
Morphometrics in Physical Anthropology/, where Booksteinis co-author,
U=|r| is used, and as in most papers.
But as said before, the only difference seems to be the "negative"
bending energy. In the article stated above the bending energy is
calculated: t(-H)(L^-1)H - instead of t(H)(L^-1)H as usually - in order to make
up for the negative semidefinite bending energy matrix.
BTW:/ "FYI Bookstein (1991) - the "orange book" gives -|r| "/ - if
the orange book is: /Bookstein F, 1991. Morphometric tools for landmark
data/ - I couldn't find it there
greetings
stefan
Stefan Schlager M.A.
Anthropologie
Medizinische Fakultät der der Albert Ludwigs- Universität Freiburg Hebelstr.
29
79104 Freiburg
Anthropology
Faculty of Medicine, Albert-Ludwigs-University Freiburg Hebelstr. 29
D- 79104 Freiburg
phone +49 (0)761 203-5522
fax +49 (0)761 203-6898
On 06/02/11 17:10, morphmet wrote:
>
>
> -------- Original Message --------
> Subject: Re: TPS 3D negative bending energy
> Date: Fri, 4 Feb 2011 21:13:03 -0500
> From: F. James Rohlf <[email protected]>
> Reply-To: [email protected]
> To: Morphmet <[email protected]>
>
> FYI Bookstein (1991) - the "orange book" gives -|r|
> -------
> Sent remotely by F. James Rohlf,
> John S. Toll Professor
>
> -----Original Message-----
> From: morphmet <[email protected]>
> Date: Fri, 04 Feb 2011 16:42:51
> To: morphmet<[email protected]>
> Reply-To: [email protected]
> Subject: Re: TPS 3D negative bending energy
>
>
>
> -------- Original Message --------
> Subject: Re: TPS 3D negative bending energy
> Date: Fri, 4 Feb 2011 15:25:49 -0500
> From: Stefan Schlager <[email protected]>
> To: [email protected]
>
>
>
> I found the kernel U=|r| in most computer journals - e.g. in /Claes et
> al., Statistically deformable face models for craniofacial
> reconstruction. Journal of Computing and Information Technology - CIT,
> 14(1):21–30, 2006.
> /
> But as it was working excellent (the non-affine part of the spline is
> t(w)*(r) instead of t(-w)*(-r) - with (w) being my "old" coefficients
> and (r) the vector of ri=||(x,y,z)-(xi,yi,zi)||) , I never questioned
> the choice of the kernel (who am to do such a thing as I am quite a
> novice to this field). Up to this week I never noticed a difference,
> as the result of the spline is exactly the same. I used TPS only for
> actual deformation of 3d-meshes.
>
> thanks for answering
> greetings stefan
>
