modifs avant vacances

diff --git a/biblio.bib b/biblio.bib
index 22bcda23a77bdf4c8fbca773ae1d1af89b1c2f00..3c06dc7406c36a8f1e0b47ba2a17b5a929dce0ed 100644 (file)
--- a/biblio.bib
+++ b/biblio.bib
@@ -25,6 +25,28 @@
   isbn      = {3-540-42733-3},
   bibsource = {DBLP, http://dblp.uni-trier.de}
 }
+
+@article{Chang20101286,
+title = "Hybrid wet paper coding mechanism for steganography employing n-indicator and fuzzy edge detector",
+journal = "Digital Signal Processing",
+volume = "20",
+number = "4",
+pages = "1286 - 1307",
+year = "2010",
+note = "",
+issn = "1051-2004",
+doi = "10.1016/j.dsp.2009.11.005",
+url = "http://www.sciencedirect.com/science/article/pii/S1051200409002413",
+author = "Chin-Chen Chang and Jung-San Lee and T. Hoang Ngan Le",
+keywords = "Security",
+keywords = "Wet paper coding",
+keywords = "Steganography",
+keywords = "Indicator",
+keywords = "Fuzzy edge detector"
+}
+
+
+
 @article{Hu:2007:HPE:1282866.1282944,
  author = {Hu, Liming and Cheng, H. D. and Zhang, Ming},
  title = {A high performance edge detector based on fuzzy inference rules},
@@ -203,7 +225,7 @@ author    = {Jessica J. Fridrich and
   interhash = {bc34a5f04661fee24ee62c39e76361be},
   intrahash = {28889a4ab329da28559f0910469f054b},
   journal = {Expert Syst. Appl.},
-  keywords = {dblp},
+  keywords = {dblp}, 
   number = 4,
   pages = {3292-3301},
   timestamp = {2010-07-21T15:44:10.000+0200},

diff --git a/experiments.tex b/experiments.tex
index 0011cd4ef7e24952f02aa34a4cda99281614e711..45f0b87967d5052182e0ffe4d39255c77edaf16f 100644 (file)
--- a/experiments.tex
+++ b/experiments.tex
@@ -1,14 +1,37 @@
 \subsection{Adaptive Embedding Rate} 
 
-
+Two strategies have been developed in our scheme with respect to the rate of 
+embedding which is either \emph{ adaptive} or \emph{fixed}.
+
+In the former the embedding rate depends on the number of edge pixels.
+The higher it is, the larger is the message length that can be considered.
+Practically, a set of edge pixels is computed according to the 
+Canny algorithm with high threshold.
+The message length is thus defined to be the half of this set cardinality.
+The rate between  available bits  and bit message length is then more than two.This constraint is indeed induced by the fact that the efficiency 
+of the stc algorithm is unsatisfactory under that threshold.
+
+
+In the latter, the embedding rate is defined as a percentage between the 
+number of the modified pixels and the length of the bit message.
+This is the classical approach adopted in steganography.
+Practically, the Canny algorithm generates a 
+a set of edge pixels with threshold that is decreasing until its cardinality
+is sufficient. If the set cardinality is more than twice larger than the 
+bit message length an stc is again applied.
+Otherwise, pixels are randomly chosen from the set of pixels to build the 
+subset with a given size. The BBS PRNG is again applied there.
+ 
+
+ 
 
 \subsection{Image Quality}
 The visual quality of the STABYLO scheme is evaluated in this section.
 Four metrics are computed in these experiments : 
 the Peak Signal to Noise Ratio (PSNR), 
-the PSNR-HVS-M familly~\cite{PSECAL07,psnrhvsm11} , 
+the PSNR-HVS-M family~\cite{PSECAL07,psnrhvsm11} , 
 the BIQI~\cite{MB10,biqi11} and 
-the weigthed PSNR (wPSNR)~\cite{DBLP:conf/ih/PereiraVMMP01}.
+the weighted PSNR (wPSNR)~\cite{DBLP:conf/ih/PereiraVMMP01}.
 The first one is widely used but does not take into
 account Human Visual System (HVS).
 The other last ones have been designed to tackle this problem.
@@ -17,8 +40,7 @@ The other last ones have been designed to tackle this problem.
 \begin{center}
 \begin{tabular}{|c|c|c|}
 \hline
-Embedding rate &  Adaptive 
-10 \% &  \\
+Embedding rate &  Adaptive & 10 \%  \\
 \hline
 PSNR &  66.55    & 61.86     \\
 \hline
@@ -30,14 +52,19 @@ wPSNR & 86.43& 77.47 \\
 \hline
 \end{tabular}
 \end{center}
-\caption{Quality measeures of our steganography approach\label{table:quality}} 
+\caption{Quality measures of our steganography approach\label{table:quality}} 
 \end{table}
 
 
-Compare to the Edge Adpative scheme detailed in~\cite{Luo:2010:EAI:1824719.1824720}, our both wPSNR and PSNR values are always higher than their ones.
-
-\JFC{comparer aux autres approaches}
-
+Let us compare the STABYLO approach with other edge based steganography
+schemes with respect to the image quality.
+Fist off all, wPSNR and PSNR of the Edge Adaptive
+scheme detailed in~\cite{Luo:2010:EAI:1824719.1824720} are lower than ours.
+Next both the approaches~\cite{DBLP:journals/eswa/ChenCL10,Chang20101286}
+focus on increasing the payload while the PSNR is acceptable, bu do not 
+give quality metrics for fixed embedding rate from a large base of images. 
+Our approach outperforms the former thanks to the introduction of the stc 
+algorithm.
 
 
 \subsection{Steganalysis}
@@ -63,7 +90,8 @@ can be a favourably executed thanks to an Ensemble Classifiers.
 \begin{table}
 \begin{center}
 \begin{tabular}{|c|c|c|c|}
-Shemes & \multicolumn{2}{|c|}{STABYLO} & HUGO\\
+\hline
+Schemes & \multicolumn{2}{|c|}{STABYLO} & HUGO\\
 \hline
 Embedding rate &  Adaptive & 10 \% &  10 \%\\
 \hline
@@ -78,3 +106,7 @@ Ensemble Classifier &   &      &      \\
 \end{table}
 
 
+Results show that our approach is more easily detectable than HUGO which is
+is the more secure steganography tool, as far we know. However due to its 
+huge number of features integration, it is not lightweight.   
+