-------- Original Message --------
Subject: Re: PCA with VERY large number of landmarks?
Date: Tue, 4 Oct 2011 21:16:06 -0400
From: Carlos Fabian Morantes Ariza <[email protected]>
To: [email protected]
Sorry, landmarks should not be more than N/2 for 2D and N/3 for 3D.
Carlos Fabian Morantes Ariza
Department of Biology
Universidad Nacional de Colombia
2011/10/4 Carlos Fabian Morantes Ariza <[email protected]
<mailto:[email protected]>>
Hi,
I think you should not use this huge amount of landmarks since
you're going to lose sensitivity and you also can't ensure
positional homology feasibility. I think you could find useful to
treat your structure as a contour or (if they are 3D data) several
soft patches. This will avoid the digitizing error. Another thing,
you're not suppose to use more than N/2 landmarks (with N being
sour sample size).
Hope this work
Carlos Fabian Morantes Ariza
Department of biology
Universidad Nacional de Colombia
2011/10/4 morphmet <[email protected]
<mailto:[email protected]>>
-------- Original Message --------
Subject: PCA with VERY large number of landmarks?
Date: Mon, 3 Oct 2011 21:48:03 -0400
From: Adam Douglas Yock <[email protected]>
<mailto:[email protected]>
To: [email protected] <mailto:[email protected]>
Hello,
I am new to the field of morphometrics and have a (potentially
very ignorant) question.
I have images that contain a deformable body and a rigid body.
The images are rigidly registered to align the rigid bodies. The
deformable bodies are described by ~5,000 points which are
matched across each image. I believe my data is then comprised
of the 3D coordinates of the ~5,000 points of the deformable
body depicted in each image.
Can I treat these points as landmarks and perform a very
high-dimensional (~15,000-D) PCA? Is there any "curse of
dimensionality" with this method?
I appreciate your help.
Adam
[email protected] <mailto:[email protected]>
