# HG changeset patch # User Yoshua Bengio # Date 1275421726 14400 # Node ID 13816dbef6ed39f6de4253922f07b3c7747098ce # Parent 18a6379999fdbbd375508ce5b0b077f811b921de des choses ont disparu diff -r 18a6379999fd -r 13816dbef6ed writeup/images/denoising_autoencoder_small.pdf Binary file writeup/images/denoising_autoencoder_small.pdf has changed diff -r 18a6379999fd -r 13816dbef6ed writeup/nips2010_submission.tex --- a/writeup/nips2010_submission.tex Tue Jun 01 11:58:14 2010 -0700 +++ b/writeup/nips2010_submission.tex Tue Jun 01 15:48:46 2010 -0400 @@ -206,7 +206,7 @@ {\bf Pinch.} This is a GIMP filter called ``Whirl and pinch'', but whirl was set to 0. A pinch is ``similar to projecting the image onto an elastic -surface and pressing or pulling on the center of the surface''~\citep{GIMP-manual}. +surface and pressing or pulling on the center of the surface'' (GIMP documentation manual). For a square input image, this is akin to drawing a circle of radius $r$ around a center point $C$. Any point (pixel) $P$ belonging to that disk (region inside circle) will have its value recalculated by taking @@ -454,6 +454,18 @@ through preliminary experiments (measuring performance on a validation set), and $0.1$ was then selected. +\begin{figure}[h] +\resizebox{0.8\textwidth}{!}{\includegraphics{images/denoising_autoencoder_small.pdf}} +\caption{Illustration of the computations and training criterion for the denoising +auto-encoder used to pre-train each layer of the deep architecture. Input $x$ +is corrupted into $\tilde{x}$ and encoded into code $y$ by the encoder $f_\theta(\cdot)$. +The decoder $g_{\theta'}(\cdot)$ maps $y$ to reconstruction $z$, which +is compared to the uncorrupted input $x$ through the loss function +$L_H(x,z)$, whose expected value is approximately minimized during training +by tuning $\theta$ and $\theta'$.} +\label{fig:da} +\end{figure} + {\bf Stacked Denoising Auto-Encoders (SDA).} Various auto-encoder variants and Restricted Boltzmann Machines (RBMs) can be used to initialize the weights of each layer of a deep MLP (with many hidden @@ -470,9 +482,9 @@ compositions of simpler ones through a deep hierarchy). Here we chose to use the Denoising Auto-Encoder~\citep{VincentPLarochelleH2008} as the building block for -% AJOUTER UNE IMAGE? these deep hierarchies of features, as it is very simple to train and -teach (see tutorial and code there: {\tt http://deeplearning.net/tutorial}), +teach (see Figure~\ref{fig:da}, as well as +tutorial and code there: {\tt http://deeplearning.net/tutorial}), provides immediate and efficient inference, and yielded results comparable or better than RBMs in series of experiments \citep{VincentPLarochelleH2008}. During training, a Denoising