On Eigenfaces: Creating ghost-like images from a set of faces

There was a generalisation of the eigenface technique to 3D published in Siggraph about 15 years ago. <a href="http://gravis.cs.unibas.ch/Sigg99.html" rel="nofollow">http:&#x2F;&#x2F;gravis.cs.unibas.ch&#x2F;Sigg99.html</a><p>One of the authors is still working on refining their approach, by the looks of it: <a href="http://gravis.cs.unibas.ch/projects.html" rel="nofollow">http:&#x2F;&#x2F;gravis.cs.unibas.ch&#x2F;projects.html</a>

(Nomen omen) spectral look is an artifact of using negative values. It&#x27;s nice to see non-negative components - <a href="http://www.quantumblah.org/?p=428" rel="nofollow">http:&#x2F;&#x2F;www.quantumblah.org&#x2F;?p=428</a>. They are both more accurate and more human-interpretable (at the cost of computational efficiency).

Here&#x27;s an animation of an autoencoder learning filter weights. It&#x27;s interesting that they look similar.<p><a href="https://lambdal.com/images/autoencoder-learning-face-filters.gif" rel="nofollow">https:&#x2F;&#x2F;lambdal.com&#x2F;images&#x2F;autoencoder-learning-face-filters...</a>

An interesting post in need of a reference to past work:<p><a href="http://www.mitpressjournals.org/doi/abs/10.1162/jocn.1991.3.1.71#.VMa5OP7F9yM" rel="nofollow">http:&#x2F;&#x2F;www.mitpressjournals.org&#x2F;doi&#x2F;abs&#x2F;10.1162&#x2F;jocn.1991.3....</a><p>nearly 25 years old and 13k references, so it&#x27;s pretty well studied...!

Classic HW problem nicely done. Today they use Viola-Jones.<p>For those wondering why PCA works (self-plug): <a href="http://ilyakava.tumblr.com/post/95691347612/demystifying-pca" rel="nofollow">http:&#x2F;&#x2F;ilyakava.tumblr.com&#x2F;post&#x2F;95691347612&#x2F;demystifying-pca</a>

Very interesting. I&#x27;d like to see something like that for sounds&#x2F;music to see how audio will evolve after several cycles of encoding&#x2F;recovering.

Isn&#x27;t this one of the homework&#x27;s in the stanford&#x2F;coursera ml course? I feel like this is not really original content

Ghost like faces? It&#x27;s as if they are... spectral<p>(•_•) ( •_•)&gt;⌐■-■ (⌐■_■)