Mercurial > ift6266
diff writeup/nips2010_submission.tex @ 551:8f365abf171d
separete the transmo image
author | Frederic Bastien <nouiz@nouiz.org> |
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date | Wed, 02 Jun 2010 17:00:11 -0400 |
parents | 662299f265ab |
children | 35c611363291 |
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--- a/writeup/nips2010_submission.tex Wed Jun 02 15:44:46 2010 -0400 +++ b/writeup/nips2010_submission.tex Wed Jun 02 17:00:11 2010 -0400 @@ -133,8 +133,18 @@ \vspace*{-1mm} \section{Perturbation and Transformation of Character Images} \label{s:perturbations} +{\large\bf Transformations} + \vspace*{-1mm} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Original.PNG} +\label{fig:Original} +\vspace{1.2cm} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Original:} This section describes the different transformations we used to stochastically transform source images in order to obtain data from a larger distribution which covers a domain substantially larger than the clean characters distribution from @@ -152,33 +162,32 @@ There are two main parts in the pipeline. The first one, from slant to pinch below, performs transformations. The second part, from blur to contrast, adds different kinds of noise. +\end{minipage} -\begin{figure}[ht] -\vspace*{-2mm} -\centerline{\resizebox{.9\textwidth}{!}{\includegraphics{images/transfo.png}}} -% TODO: METTRE LE NOM DE LA TRANSFO A COTE DE CHAQUE IMAGE -\caption{Illustration of each transformation applied alone to the same image -of an upper-case h (top left). First row (from left to right) : original image, slant, -thickness, affine transformation (translation, rotation, shear), -local elastic deformation; second row (from left to right) : -pinch, motion blur, occlusion, pixel permutation, Gaussian noise; third row (from left to right) : -background image, salt and pepper noise, spatially Gaussian noise, scratches, -grey level and contrast changes.} -\label{fig:transfo} -\vspace*{-2mm} -\end{figure} -{\large\bf Transformations} - -\vspace*{0.5mm} - -{\bf Slant.} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Slant_only.PNG} +\label{fig:Slant} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +%\centering +{\bf Slant:} Each row of the image is shifted proportionally to its height: $shift = round(slant \times height)$. $slant \sim U[-complexity,complexity]$. -\vspace*{-1mm} +\vspace{1.2cm} +\end{minipage} + -{\bf Thickness.} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Thick_only.PNG} +\label{fig:Think} +\vspace{.9cm} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Thinkness:} Morphological operators of dilation and erosion~\citep{Haralick87,Serra82} are applied. The neighborhood of each pixel is multiplied element-wise with a {\em structuring element} matrix. @@ -190,9 +199,18 @@ where $m=10$ for dilation and $m=6$ for erosion (to avoid completely erasing thin characters). A neutral element (no transformation) is always present in the set. is applied. -\vspace*{-1mm} +\vspace{.4cm} +\end{minipage} +\vspace{-.7cm} + -{\bf Affine Transformations.} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Affine_only.png} +\label{fig:Affine} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Affine Transformations:} A $2 \times 3$ affine transform matrix (with 6 parameters $(a,b,c,d,e,f)$) is sampled according to the $complexity$ level. Output pixel $(x,y)$ takes the value of input pixel @@ -204,18 +222,33 @@ complexity,1+3 \times complexity]$, $b$ and $e$ $\sim[-3 \times complexity,3 \times complexity]$ and $c$ and $f$ $\sim U[-4 \times complexity, 4 \times complexity]$. -\vspace*{-1mm} +\end{minipage} -{\bf Local Elastic Deformations.} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Localelasticdistorsions_only.PNG} +\label{fig:Elastic} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Local Elastic Deformations:} This filter induces a ``wiggly'' effect in the image, following~\citet{SimardSP03-short}, which provides more details. The intensity of the displacement fields is given by $\alpha = \sqrt[3]{complexity} \times 10.0$, which are convolved with a Gaussian 2D kernel (resulting in a blur) of standard deviation $\sigma = 10 - 7 \times\sqrt[3]{complexity}$. -\vspace*{-1mm} +\vspace{.4cm} +\end{minipage} +\vspace{-.7cm} -{\bf Pinch.} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Pinch_only.PNG} +\label{fig:Pinch} +\vspace{.6cm} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Pinch:} This is the ``Whirl and pinch'' GIMP filter but with 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'' (GIMP documentation manual). @@ -230,22 +263,38 @@ The actual value is given by bilinear interpolation considering the pixels around the (non-integer) source position thus found. Here $pinch \sim U[-complexity, 0.7 \times complexity]$. +%\vspace{1.5cm} +\end{minipage} -\vspace*{0.5mm} +\vspace{.1cm} {\large\bf Injecting Noise} -\vspace*{0.5mm} - -{\bf Motion Blur.} +\vspace*{-.2cm} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Original.PNG} +\label{fig:Original} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Motion Blur:} This is GIMP's ``linear motion blur'' with parameters $length$ and $angle$. The value of a pixel in the final image is approximately the mean value of the first $length$ pixels found by moving in the $angle$ direction. Here $angle \sim U[0,360]$ degrees, and $length \sim {\rm Normal}(0,(3 \times complexity)^2)$. -\vspace*{-1mm} +\vspace{.7cm} +\end{minipage} + +\vspace*{-5mm} -{\bf Occlusion.} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Original.PNG} +\label{fig:Original} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Occlusion:} Selects a random rectangle from an {\em occluder} character image and places it over the original {\em occluded} image. Pixels are combined by taking the max(occluder,occluded), @@ -254,35 +303,76 @@ The destination position in the occluded image are also sampled according to a normal distribution (more details in~\citet{ift6266-tr-anonymous}). This filter is skipped with probability 60\%. -\vspace*{-1mm} +\vspace{.4cm} +\end{minipage} -{\bf Pixel Permutation.} -This filter permutes neighbouring pixels. It first selects +\vspace*{-5mm} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Original.PNG} +\label{fig:Original} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Pixel Permutation:} +This filter permutes neighbouring pixels. It first selects fraction $\frac{complexity}{3}$ of pixels randomly in the image. Each of them are then sequentially exchanged with one other in as $V4$ neighbourhood. This filter is skipped with probability 80\%. -\vspace*{-1mm} +\vspace{.8cm} +\end{minipage} + -{\bf Gaussian Noise.} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Original.PNG} +\label{fig:Original} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Gaussian Noise:} This filter simply adds, to each pixel of the image independently, a noise $\sim Normal(0,(\frac{complexity}{10})^2)$. This filter is skipped with probability 70\%. -\vspace*{-1mm} +\vspace{1.1cm} +\end{minipage} +\vspace{-.7cm} -{\bf Background Images.} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Original.PNG} +\label{fig:Original} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Background Images:} Following~\citet{Larochelle-jmlr-2009}, this transformation adds a random background behind the letter, from a randomly chosen natural image, with contrast adjustments depending on $complexity$, to preserve more or less of the original character image. -\vspace*{-1mm} +\vspace{.8cm} +\end{minipage} +\vspace{-.7cm} -{\bf Salt and Pepper Noise.} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Original.PNG} +\label{fig:Original} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Salt and Pepper Noise:} This filter adds noise $\sim U[0,1]$ to random subsets of pixels. The number of selected pixels is $0.2 \times complexity$. This filter is skipped with probability 75\%. -\vspace*{-1mm} +\vspace{.9cm} +\end{minipage} +\vspace{-.7cm} -{\bf Spatially Gaussian Noise.} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Original.PNG} +\label{fig:Original} +\vspace{.5cm} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Spatially Gaussian Noise:} Different regions of the image are spatially smoothed by convolving the image is convolved with a symmetric Gaussian kernel of size and variance chosen uniformly in the ranges $[12,12 + 20 \times @@ -296,9 +386,17 @@ computed from the following element-wise operation: $\frac{image + filtered image \times mask}{mask+1}$. This filter is skipped with probability 75\%. -\vspace*{-1mm} +\end{minipage} +\vspace{-.7cm} -{\bf Scratches.} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Original.PNG} +\label{fig:Original} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +\vspace{.4cm} +{\bf Scratches:} The scratches module places line-like white patches on the image. The lines are heavily transformed images of the digit ``1'' (one), chosen at random among 500 such 1 images, @@ -309,13 +407,24 @@ by an amount controlled by $complexity$. This filter is skipped with probability 85\%. The probabilities of applying 1, 2, or 3 patches are (50\%,30\%,20\%). -\vspace*{-1mm} +\end{minipage} +\vspace{-.7cm} -{\bf Grey Level and Contrast Changes.} +\begin{minipage}[b]{0.14\linewidth} +\centering +\includegraphics[scale=.45]{images/Original.PNG} +\label{fig:Original} +\end{minipage}% +\hspace{0.3cm}\begin{minipage}[b]{0.86\linewidth} +{\bf Grey Level and Contrast Changes:} This filter changes the contrast and may invert the image polarity (white to black and black to white). The contrast is $C \sim U[1-0.85 \times complexity,1]$ so the image is normalized into $[\frac{1-C}{2},1-\frac{1-C}{2}]$. The polarity is inverted with probability 50\%. +\vspace{.7cm} +\end{minipage} +\vspace{-.7cm} + \iffalse \begin{figure}[ht]