[Insight-users] How to compute "PCA shape model"?

[闵小平]

Hi  Zach :
    Thank you for your reply.
    I have read the code in itkImagePCAShapeModelEstimator.txx . It seems that the mean image and principal component outputs are 
generated in this class,and the inputs of this class is TrainingImages. So i wondered what the  "signed distance maps a set of  
training shapes " mean in your reply, and how can i input these images.
    In the quoted code, the shape model defined by CorpusCallosumMeanShape.mha and the first three principal
components CorpusCallosumMode0.mha, CorpusCallosumMode1.mha and CorpusCallosumMode12.mha. How can i generate
these mha files? Can i write the principal component outputs of itkImagePCAShapeModelEstimator class in  mha files
directly?

Thanks
Sunli

----- Original Message ----- 
From: "Zachary Pincus" <zpincus at stanford.edu>
To: "sun" <kacking123 at 163.com>
Cc: "itk" <insight-users at itk.org>
Sent: Sunday, May 28, 2006 3:41 AM
Subject: Re: [Insight-users] How to compute "PCA shape model"?



This is a longstanding gap in the documentation.

In brief, you will need to generate signed distance maps of a set of  
training shapes, and pass them to the PCAShapeModelEstimator class.  
You may then choose to divide the returned "shape mode" images (note  
that output zero from the model estimator is the mean image) by the  
reported standard deviations, as described in the example.

Let me know if more detail is required.

Zach Pincus

Program in Biomedical Informatics and Department of Biochemistry
Stanford University School of Medicine


On May 27, 2006, at 12:06 AM, sun wrote:

> Hi all:
>      I am using the filter "Geodesic Active Contours Segmentation  
> with Shape Guidance" to
> segment my image now.But the quoted  code just reads in a "PCA  
> shape model" that has been pre-computed
> earlier. I want to know how to compute such a shape model in  ITK.
> Who can help me?
>                                       sun li
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