The edge detection returns 18,641 and 18,455 pixels when $b$ is
respectively 7 and 6. These edges are represented in Figure~\ref{fig:edge}.
When $b$ is 7, it remains one bit per pixel to build the cover vector.
-in this configuration, this leads to a cover vector of size 18,641 and
-36,910 if $b$ is 6.
+in this configuration, this leads to a cover vector of size 18,641 if b is 7
+and 36,910 if $b$ is 6.
\begin{figure}[t]
\begin{center}
The STC algorithm is optimized when the rate between message length and
cover vector length is less than 1/2.
-So, only 9,320 bits (resp. 18,455 bits) are available for embedding
-in the former configuration where $b$ is 7 (resp. where $b$ is 6).
-In the first cases, about the third part of the poem is hidden into the cover
-whereas the latter allows to embed more than the half part of it.
+So, only 9,320 bits are available for embedding
+in the configuration where $b$ is 7.
+
+When $b$ is 6, we could have considered 18,455 bits for the message.
+However, first experiments have shown that modifying this number of bits is too
+easily detectable.
+So, we choose to modify the same amount of bits (9,320) and keep STC optimizing
+which bits to change among the 36,910 bits.
+
+In the two cases, about the third part of the poem is hidden into the cover.
Results with \emph{adaptive+STC} strategy are presented in
Fig.~\ref{fig:lenastego}.
