X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/canny.git/blobdiff_plain/8290657e61738a93b7b6eb60966c49efbc4f0af8..f919ede766f1129e330f7d12d04ed3e8ca8111b0:/stc.tex?ds=inline diff --git a/stc.tex b/stc.tex index 6570c73..16fbfb3 100644 --- a/stc.tex +++ b/stc.tex @@ -58,15 +58,12 @@ $2^n-1$ pixels needs $1-1/2^n$ average changes. -Unfortunately, - - -for any given $H$, finding $y$ that solves $Hy=m$ and that +Unfortunately, for any given $H$, finding $y$ that solves $Hy=m$ and that that minimizes $D_X(x,y)$ has exponential complexity with respect to $n$. The Syndrome-Trellis Codes (STC) presented by Filler et al. in~\cite{DBLP:conf/mediaforensics/FillerJF10} is a practical solution to this complexity. Thanks to this contribution, -the solving algorithm has a linear complexity with resspect to $n$. +the solving algorithm has a linear complexity with respect to $n$. First of all, Filler et al. compute the matrix $H$ by placing a small sub-matrix $\hat{H}$ of size $h × w$ next @@ -80,6 +77,6 @@ Next, the process of finding $y$ consists of a forward and a backward part: \item Backward determinization of $y$ which minimizes $D$ starting with the complete path with minimal weight \end{enumerate} -Let us now give some details about these two parts. +