Can PCA be applied directly on an image?

Can PCA be applied directly on an image, in contrast to a matrix(in which rows correspond to observations & columns to variables)?

When i try to apply PCA using SVD/Covariance directly on an image i get the following error:

"Error using minus

 Integers can only be combined with integers of same class or scalar doubles.

 Error in pca2 at 14
 data=data-repmat(mn,1,N);"

Thanking you in advance

[Algorithms Analyst]

Check ur image type should be double date try.

[sidra]

Algorithms Analyst ,the image type is double.

Answer 1

[Walter Roberson]

Apply it to im2double() of the image.

Answer 2

[sidra]

Walter, it works fine for a single image but when i try the same on array of images i get the error :

"Array dimensions must match for binary array op.

error in pca2 at 14

data=data-repmat(mn,1,N);

error in db.pca at 18

pc=pca2(imagearray);"

[sidra]

Any suggestions?