j'ai rajouté une figure avec l'erreur, la valeur du milieu est interpolée :-)

[canny.git] / ourapproach.tex

diff --git a/ourapproach.tex b/ourapproach.tex
index 35376405172d6ca2d35c1e93beb8ed3b1839dc62..534fb29fc23e96d7d6925ad413bdb8243aae41a8 100644 (file)
--- a/ourapproach.tex
+++ b/ourapproach.tex
@@ -48,6 +48,8 @@ Let us first focus on the data embedding.
 
 
 \subsection{Security considerations}\label{sub:bbs}
 
 
 \subsection{Security considerations}\label{sub:bbs}

+\JFC{To provide a self-contained article without any bias, we shortly 
+pressent the retained encryption process.}

 Among the methods of  message encryption/decryption 
 (see~\cite{DBLP:journals/ejisec/FontaineG07} for a survey)
 we implement the asymmetric 
 Among the methods of  message encryption/decryption 
 (see~\cite{DBLP:journals/ejisec/FontaineG07} for a survey)
 we implement the asymmetric 


@@ -140,7 +142,7 @@ In the former the embedding rate depends on the number of edge pixels.
 The higher it is, the larger the message length that can be inserted is.
 Practically, a set of edge pixels is computed according to the 
 Canny algorithm with parameters $b=7$ and $T=3$.
 The higher it is, the larger the message length that can be inserted is.
 Practically, a set of edge pixels is computed according to the 
 Canny algorithm with parameters $b=7$ and $T=3$.

-The message length is thus defined to be less than 
+The message length is thus defined to be lesser than 

 half of this set cardinality.
 If $x$ is too short for $m$, the message is split into sufficient parts
 and a new cover image should be used for the remaining part of the message. 
 half of this set cardinality.
 If $x$ is too short for $m$, the message is split into sufficient parts
 and a new cover image should be used for the remaining part of the message. 


@@ -151,13 +153,13 @@ This is the classical approach adopted in steganography.
 Practically, the Canny algorithm generates  
 a set of edge pixels related to increasing values of $T$ and 
 until its cardinality
 Practically, the Canny algorithm generates  
 a set of edge pixels related to increasing values of $T$ and 
 until its cardinality

-is sufficient. Even in this situation, our scheme is adapting 
+is sufficient. Even in this situation, our scheme adapts

 its algorithm to meet all the user's requirements. 
 
 
 Once the map of possibly modified pixels is computed, 
 two methods may further be applied to extract bits that 
 its algorithm to meet all the user's requirements. 
 
 
 Once the map of possibly modified pixels is computed, 
 two methods may further be applied to extract bits that 

-are really modified. 
+are really changed. 

 The first one randomly chooses the subset of pixels to modify by 
 applying the BBS PRNG again. This method is further denoted  as a \emph{sample}.
 Once this set is selected, a classical LSB replacement is applied to embed the 
 The first one randomly chooses the subset of pixels to modify by 
 applying the BBS PRNG again. This method is further denoted  as a \emph{sample}.
 Once this set is selected, a classical LSB replacement is applied to embed the 


@@ -197,7 +199,7 @@ It  is further referred to as \emph{STC} and is detailed in the next section.
 % the fuzzy logic edge detector.   
 
 For a given set of parameters, 
 % the fuzzy logic edge detector.   
 
 For a given set of parameters, 

-the canny algorithm returns a numerical value and
+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 
 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 


@@ -226,7 +228,7 @@ follows the data embedding approach
 since there exists a reverse function for all its steps.
 
 More precisely,  let $b$ be the most significant bits and 
 since there exists a reverse function for all its steps.
 
 More precisely,  let $b$ be the most significant bits and 

-$T$ be the size of the canny mask, both be given as a key.
+$T$ be the size of the Canny mask, both be given as a key.

 Thus, the same edge detection is applied on a stego content $Y$ to 
 produce the sequence $y$ of LSBs. 
 If the STC approach has been selected in embedding, the STC reverse
 Thus, the same edge detection is applied on a stego content $Y$ to 
 produce the sequence $y$ of LSBs. 
 If the STC approach has been selected in embedding, the STC reverse


@@ -358,7 +360,7 @@ V_{ij}= \left\{
 150 & \textrm{if} &  \vert X_{ij} - Y_{ij} \vert = 2 \\
 225 & \textrm{if} &  \vert X_{ij} - Y_{ij} \vert = 3 
 \end{array}
 150 & \textrm{if} &  \vert X_{ij} - Y_{ij} \vert = 2 \\
 225 & \textrm{if} &  \vert X_{ij} - Y_{ij} \vert = 3 
 \end{array}

-\right..
+\right.

 $$
 This function allows to emphasize differences between contents.
 Notice that since $b$ is 7 in Fig.~\ref{fig:diff7}, the embedding is binary 
 $$
 This function allows to emphasize differences between contents.
 Notice that since $b$ is 7 in Fig.~\ref{fig:diff7}, the embedding is binary