Re: About BIJ PCA usage

Posted by Xin ZHOU on Mar 15, 2009; 11:07am
URL: http://imagej.273.s1.nabble.com/About-BIJ-PCA-usage-tp3693307p3693309.html

Gabriel Landini a écrit :

> On Saturday 14 March 2009, Xin ZHOU wrote:
>  
>> I would like to use the PCA transformation to reduce the dimension of
>> the features.
>> However, even it exist PCA components in BIJ plugins, no documents are
>> gieven.
>> Can some one give an example of how to use it?
>>    
>
> You submit a stack of images. Each slice represents a different variable. So
> for pixel (x,y) across the stack, the z value are the variables associated to
> it.
> The result should be another stack in which each slice is a component. You
> also get a Eigenvalue spectrum plot which shows the amount of the total
> variance explained by each component.
>
> I hope it helps
>
> G.
>
>  

Hello,
 
First of all, I didn't represent a image as a vector, but a feature.
Secondly, I'm not looking for the theory, but an implementation, like :

a is the set of vector and c is the result,
the function is c=new PCA(a) ......

Because in the javadoc I didn't find the entry point for this class at
all, so I'm looking for how to use it.

Yes, by the way, I'm programming with ImageJ, so not just look for a
button to click on :-)

cheers, Xin