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Commit 4dc99b67 authored by even's avatar even
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Article: blurred segments revisited

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......@@ -66,8 +66,8 @@ The search direction is fixed by the support vector of the blurred segment
detected at the former step, and because the set of vectors in a bounded
discrete space is finite, there is necessarily a limit on this direction
accuracy.
It results that more steps would be necessary to process higher resolution
images.
It results that more steps would inevitably be necessary to process higher
resolution images.
\subsection{Main contritions}
......
......@@ -14,10 +14,11 @@ is the set of points $P(x,y)$ of $\mathbb{Z}^2$ that satisfy :
$0 \leq ax + by - c < \nu$.
\end{definition}
$b/a$ is the slope of $\mathcal{L}$, $c$ its intercept and $\nu$
its arithmetic width.
When $\nu = max (|a|, |b|)$, $\mathcal{L}$ is the narrowest 8-connected
line and is called a naive line.
The parameters of the digital line are its slope $b/a$, its height $c$
and its arithmetic width $\nu$. The set of points is organized as a
periodic pattern of length $p = (|a|, |b|)$.
When $\nu = p$, $\mathcal{L}$ is the narrowest 8-connected line
and is called a naive line.
\begin{definition}
A blurred segment $\mathcal{B}$ of assigned width $\varepsilon$ is a set
......@@ -32,8 +33,8 @@ segment when adding each point successively.
The minimal width $\mu$ of the blurred segment $\mathcal{B}$ is the
arithmetical width of the narrowest digital straight line that contains
$\mathcal{B}$.
It is also the minimal width of the convex hull, that is computed by
Melkman's algorithm \cite{Melkman87}.
It is also the minimal width of the convex hull of $\mathcal{B}$,
that can be computed by Melkman's algorithm \cite{Melkman87}.
The extension of the blurred segment $\mathcal{B}_i$ of assigned width
$\varepsilon$ and minimal width $\mu_i$ at step $i$ with a new input point
$P_{i+1}$ is thus controlled by the recognition test $\mu_{i+1} < \varepsilon$.
......@@ -48,11 +49,14 @@ the assigned width $\varepsilon$, then the new input point is rejected.}
\label{fig:bs}
\end{figure}
At the beginning, a large width $\varepsilon$ is assigned to the
The control of the assigned width $\varepsilon$ is ensured on the
following way.
At the beginning, a large width $\varepsilon_0$ is assigned to the
recognition problem to allow the detection of large blurred segments.
Then, when no more aumentation of the minimal width is observed as the segment
grows, the assigned width is fixed to the observed minimal width in order to
avoid the incorporation of spurious outliers in further parts of the segment.
Then, when no more aumentation of the minimal width is observed as the
segment grows ($\mu_{i+\lambda} = \mu_i$), the assigned width is fixed
to the observed minimal width in order to avoid the incorporation of
spurious outliers in further parts of the segment.
\subsection{Directional scan}
......
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