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Thread Subject:
eigenfaces order in matrix

Subject: eigenfaces order in matrix

From: shahnaz fatima

Date: 5 Apr, 2011 18:55:22

Message: 1 of 2

i have a database of 400 faces images .i represent each facial image as a vector of 10304x1.

i subtract the mean from all columns corresponding to each image and merge them to form a matrix 10304x400.

then i find L and eigen vectors and eigen values of L
 L = A'*A; % L is the surrogate of covariance matrix C=A*A'.
[V D] = eig(L)

then i ty to limit the number of eigenvectors using some threshold.

and then find the eigenfaces as , eigenfaces= A*V ;

this eignfces is a 400 column matrix and whn i try to plot it i am gtting good ignfacs but the problem is that i am getting most dull eigen facs as say first 100 and little bit improvd in nxt 100 like that.

but i think thy should be like first ten columns should corrspond to the first person and hence among the first 10 only i should be able to see varioations in clarity. and so on for the rst of the persons.

in what order are the eigenfaces?

i mean how do i get the 10 faces of the first person and so on.

please explain
 

Subject: eigenfaces order in matrix

From: Florin Neacsu

Date: 5 Apr, 2011 21:13:05

Message: 2 of 2

"shahnaz fatima" <shahnaz1981fat@gmail.com> wrote in message <infoiq$jgv$1@fred.mathworks.com>...
> i have a database of 400 faces images .i represent each facial image as a vector of 10304x1.
>
> i subtract the mean from all columns corresponding to each image and merge them to form a matrix 10304x400.
>
> then i find L and eigen vectors and eigen values of L
> L = A'*A; % L is the surrogate of covariance matrix C=A*A'.
> [V D] = eig(L)
>
> then i ty to limit the number of eigenvectors using some threshold.
>
> and then find the eigenfaces as , eigenfaces= A*V ;
>
> this eignfces is a 400 column matrix and whn i try to plot it i am gtting good ignfacs but the problem is that i am getting most dull eigen facs as say first 100 and little bit improvd in nxt 100 like that.
>
> but i think thy should be like first ten columns should corrspond to the first person and hence among the first 10 only i should be able to see varioations in clarity. and so on for the rst of the persons.
>
> in what order are the eigenfaces?
>
> i mean how do i get the 10 faces of the first person and so on.
>
> please explain
>

Hi,

Is this http://www.cs.princeton.edu/~cdecoro/eigenfaces/ what you are trying to do ?

At the bottom of the page you can find all the .m files they used.

Florin

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