of spatial least significant bits (LSBs) replacement schemes.
Let us recall that, in this LSBR category, a subset of all the LSBs of the cover image is modified
with a secret bit stream depending on: a secret key, the cover, and the message to embed.
-In this well studied steganographic approach,
+In this well-studied steganographic approach,
if we consider that a LSB is the last bit of each pixel value,
pixels with an even value (resp. an odd value)
are never decreased (resp. increased),
thus such schemes may break the
structural symmetry of the host images.
And these structural alterations can be detected by
-well designed statistical investigations, leading to known steganalysis methods~\cite{DBLP:journals/tsp/DumitrescuWW03,DBLP:conf/mmsec/FridrichGD01,Dumitrescu:2005:LSB:1073170.1073176}.
+well-designed statistical investigations, leading to known steganalysis methods~\cite{DBLP:journals/tsp/DumitrescuWW03,DBLP:conf/mmsec/FridrichGD01,Dumitrescu:2005:LSB:1073170.1073176}.
Let us recall too that this drawback
can be corrected considering the LSB matching (LSBM) subcategory, in which
the $+1$ or $-1$ is randomly added to the cover pixel LSB value
only if this one does not correspond to the secret bit.
%TODO : modifier ceci
-Since it is possible to make that probabilities of increasing or decreasing the pixel value, for instance by considering well encrypted hidden messages, usual statistical approaches
+By considering well-encrypted hidden messages, probabilities of increasing or ofdecreasing value of pixels are equal. Then usual statistical approaches
cannot be applied here to discover stego-contents in LSBM.
The most accurate detectors for this matching are universal steganalysers such as~\cite{LHS08,DBLP:conf/ih/Ker05,FK12},
which classify images according to extracted features from neighboring elements of residual noise.
the most interesting
approaches being detailed in~\cite{Luo:2010:EAI:1824719.1824720} and
in~\cite{DBLP:journals/eswa/ChenCL10}.
-In the former, the authors presents the Edge Adaptive
-Image Steganography based on lsb matching revisited further denoted as to
+In the former, the authors present the Edge Adaptive
+Image Steganography based on LSB matching revisited further denoted as to
EAISLSBMR. This approach selects sharper edge
regions with respect
to a given embedding rate: the larger the number of bits to be embedded, the coarser
thanks to extensive experiments.
However, it has been shown that the distinguishing error with LSB embedding is lower than
the one with some binary embedding~\cite{DBLP:journals/tifs/FillerJF11}.
-We thus propose to take benefit of these optimized embedding, provided they are not too time consuming.
+We thus propose to take benefit of these optimized embeddings, provided they are not too time consuming.
In the latter, an hybrid edge detector is presented followed by an ad hoc
embedding.
The Edge detection is computed by combining fuzzy logic~\cite{Tyan1993}
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 signal.
+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.
% Message extraction is achieved by computing the same
will not be able to obtain the original message content.
Doing so makes our steganographic protocol, to a certain extend, an asymmetric one.
-To sum up, in this research work, well studied and experimented
+To sum up, in this research work, well-studied and experimented
techniques of signal processing (adaptive edges detection),
-coding theory (syndrome-treillis codes), and cryptography
+coding theory (syndrome-trellis codes), and cryptography
(Blum-Goldwasser encryption protocol) are combined
to compute an efficient steganographic
scheme, whose principal characteristic is to take into
consideration the cover image and to be compatible with small computation resources.
The remainder of this document is organized as follows.
-Section~\ref{sec:ourapproach} presents the details of the proposed steganographic scheme.
+Section~\ref{sec:ourapproach} presents the details of the proposed steganographic scheme and applies it on a running example.
Section~\ref{sec:experiments} shows experiments on image quality, steganalytic evaluation, complexity of our approach,
-and compares it to the state of the art steganographic schemes.
+and compare them to the state of the art steganographic schemes.
Finally, concluding notes and future work are given in Section~\ref{sec:concl}.
