reprise intro

diff --git a/experiments.tex b/experiments.tex
index 5ba43dfa16ae206dcee8557c46adc9ef457b7645..498e47285d12a7f5ae95b3f3c2304f0d86375d56 100644 (file)
--- a/experiments.tex
+++ b/experiments.tex
@@ -1,5 +1,5 @@
 First of all, the whole code of STABYLO can be downloaded
 First of all, the whole code of STABYLO can be downloaded

-\footnote{\url{http://members.femto-st.fr/raphael-couturier/stabylo/}}.
+\footnote{\url{http://http://members.femto-st.fr/jf-couchot/en/stabylo}}.

 For all the experiments, the whole set of 10,000 images 
 of the BOSS contest~\cite{Boss10} database is taken. 
 In this set, each cover is a $512\times 512$
 For all the experiments, the whole set of 10,000 images 
 of the BOSS contest~\cite{Boss10} database is taken. 
 In this set, each cover is a $512\times 512$

diff --git a/intro.tex b/intro.tex
index 4c995485716a5bc6b9d0b6babe006ab7178f5350..cd2aeea16a1ed0cf355eb5ece703a5a1668ddf0e 100644 (file)
--- a/intro.tex
+++ b/intro.tex
@@ -57,7 +57,7 @@ Thus a distortion measure for each
 pixel is individually determined as the sum of the differences between
 the features of the SPAM computed from the cover and from the stego images.
 The features embedded in WOW and UNIWARD are based on Wavelet-based 
 pixel is individually determined as the sum of the differences between
 the features of the SPAM computed from the cover and from the stego images.
 The features embedded in WOW and UNIWARD are based on Wavelet-based 

-directional filter. Thus, similarelly, the distortion function is 
+directional filter. Thus, similarly, the distortion function is 

 the sum  of the differences between these wavelet coefficients  
 computed from the cover and from the stego images.
 
 the sum  of the differences between these wavelet coefficients  
 computed from the cover and from the stego images.
 


@@ -108,10 +108,27 @@ One can notice that all the previously referenced
 sche\-mes~\cite{Luo:2010:EAI:1824719.1824720,DBLP:journals/eswa/ChenCL10,DBLP:conf/ih/PevnyFB10}
 produce stego contents 
 by only considering the payload, not the type of image signal: the higher the payload is, 
 sche\-mes~\cite{Luo:2010:EAI:1824719.1824720,DBLP:journals/eswa/ChenCL10,DBLP:conf/ih/PevnyFB10}
 produce stego contents 
 by only considering the payload, not the type of image signal: the higher the payload is, 

-the better the approach is said to be. 
-Contrarily, we argue that some images should not be taken as a cover because of the nature of their signals.
-Consider for instance a uniformly black image: a very tiny modification of its pixels can be easily detectable.  
-The approach we propose is thus to provide a self adaptive algorithm with a high payload, which depends on the  cover signal. 
+the better the approach is said to be.
+For instance, studied payloads range from 0.04 to 0.4 modified bits per pixel.
+Contrarily, we argue that some images should not be taken 
+as a cover because of the nature of their signals.
+Consider for instance a uniformly black image: a very tiny modification of its 
+pixels can be easily detectable.
+Practically speaking, if Alice would send
+a hidden message to Bob, she would never consider
+such kind of image and a high embedding rate.   
+The approach we propose here is thus to provide a small complexity 
+self adaptive algorithm
+with an acceptable payload, which 
+depends on the  cover signal. 
+The payload is further said to  
+ be acceptable if it  allows to embed a sufficiently 
+long message in the cover signal. 
+Practically speaking, our approach is efficient enough for
+payloads close to 0.06 bit per pixel which allows to embed 
+messages of length larger than 16000 bits in an 
+image of size $512\times 512$ pixels. 
+

 % Message extraction is achieved by computing the same
 % edge detection pixels set for the cover and the stego image. 
 % The edge detection algorithm is thus not applied  on all the bits of the image,
 % Message extraction is achieved by computing the same
 % edge detection pixels set for the cover and the stego image. 
 % The edge detection algorithm is thus not applied  on all the bits of the image,

diff --git a/main.tex b/main.tex
index e6405e611c0e4388f9ba299e0841d39335c8533b..e82040e955deb0b1364bd47b6607b3847aef4539 100755 (executable)
--- a/main.tex
+++ b/main.tex
@@ -147,8 +147,15 @@ to face steganalysers.
 
 
 For future work, the authors' intention is to investigate systematically 
 
 
 For future work, the authors' intention is to investigate systematically 

-all the existing edge detection methods, to see if the STABYLO evaluation scores can
-be improved by replacing Canny with another edge filter. 
+all the existing edge detection methods, 
+to see if the STABYLO evaluation scores can
+be improved by replacing Canny with another edge filter.
+Moreover, we plan to improve the distortion function by integrating 
+into a numerical cost the gradient value of this kind of
+algorithm. We could thus transmit this value to STC contrary to the current 
+version where the distortion that is transmited is either 1 in 
+the adaptive strategy or 1,10, 100 in the fixed strategy.
+

 Other steganalysers than the ones used in this document will be
 examined for the sake of completeness. Finally, the
 systematic replacement of all the LSBs of edges by binary digits provided
 Other steganalysers than the ones used in this document will be
 examined for the sake of completeness. Finally, the
 systematic replacement of all the LSBs of edges by binary digits provided

diff --git a/ourapproach.tex b/ourapproach.tex
index 12b3a32e57196247fac6bfca83e750c98f9d444c..35376405172d6ca2d35c1e93beb8ed3b1839dc62 100644 (file)
--- a/ourapproach.tex
+++ b/ourapproach.tex
@@ -196,14 +196,26 @@ It  is further referred to as \emph{STC} and is detailed in the next section.
 % but the whole approach can be updated to consider 
 % the fuzzy logic edge detector.   
 
 % but the whole approach can be updated to consider 
 % the fuzzy logic edge detector.   
 

-% Next, following~\cite{Luo:2010:EAI:1824719.1824720}, our scheme automatically
-% modifies Canny parameters to get a sufficiently large set of edge bits: this 
-% one is practically enlarged untill its size is at least twice as many larger 
-% than the size of embedded message.
-
-
-
-%%RAPH: paragraphe en double :-)
+For a given set of parameters, 
+the canny algorithm returns a numerical value and
+states whether a given pixel is an edge or not.
+In this article, in the Adaptive strategy 
+we consider that all the edge pixels that 
+have been selected by this algorithm have the same
+distortion cost \textit{i.e.} $\rho_X$ is always 1 for these bits. 
+In the Fixed strategy, since pixels that are detected to be edge
+with small values of $T$ (e.g. when $T=3$) 
+are more accurate than these with higher values of $T$,
+we give to STC the following distortion map of the corresponding bits
+$$  
+\rho_X= \left\{ 
+\begin{array}{l}
+1 \textrm{ if an edge for $T=3$} \\
+10 \textrm{ if an edge for $T=5$} \\
+100 \textrm{ if an edge for $T=7$}
+\end{array}
+\right.
+$$.