Skip to content
Snippets Groups Projects
Commit 0aec1d29 authored by even's avatar even
Browse files

Article blurred segment width

parent 7e1f8b0e
No related branches found
No related tags found
No related merge requests found
\begin{picture}(220,60)
\multiput(0,6)(2,-6){2}{\line(3,1){150}}
\multiput(0,8)(30,6){8}{\line(5,1){10}}
\multiput(0,18)(30,6){8}{\line(5,1){10}}
\put(45,21){\circle*{3}}
\put(55,21){\circle*{3}}
\put(65,21){\circle*{3}}
\put(75,26){\circle*{3}}
\put(82.5,31){\circle*{3}}
\put(90,36){\circle*{3}}
\put(100,36){\circle*{3}}
\put(70,35){$\mathcal{B}$}
\put(110,30){\circle{3}}
\put(112,21){$P'$}
\put(140,36){\vector(0,1){10}}
\put(140,62.66){\vector(0,-1){10}}
\put(130,55){$\mu$}
\put(160,30){\vector(0,1){10}}
\put(160,60){\vector(0,-1){10}}
\put(164,44){$\mu '$}
\end{picture}
......@@ -85,3 +85,20 @@
month="April",
pages="11--12"
}
@InProceedings{NatsumiAl08,
author={Natsumi, Hiroaki and Sugimoto, Akihiro and Kenmochi, Yukiko},
title={Predicting corresponding region in a third view using
discrete epipolar lines.},
bookTitle={14th IAPR International Conference on Discrete Geometry
for Computer Imagery},
editor = {},
optaddress={Lyon, France},
pages={470--481},
month={April 16-18},
year={2008},
volume = {4992},
series = {LNCS},
publisher = {Springer}
}
......@@ -21,5 +21,4 @@ Les filtres en fin de tracking sont l\`a pour soigner, pas pour gu\'erir.
Perspectives : validation sur contextes applicatifs.
\section*{Acknowledgements}
This work was supported by La Cabane au Darou.
%\section*{Acknowledgements}
......@@ -14,13 +14,20 @@ supervided context \cite{EvenMalavaud00}.
Most of works aim at reducing their time complexity. }
These methods rarely provide a direct measure of the quality of the output
edge, such as sharpness, connectivity or scattering. Some information may
often be drawn from their specific context, for example through
an analysis of the peak in a Hough transform accumulator, or ...
edge, such as sharpness, connectivity or scattering.
Some information may often be drawn from their specific context, for example
through an analysis of the peak in a Hough transform accumulator, or
TO COMPLETE.
In particular, the accuracy of the edge orientation may be quite critical
in some application contexts, such as computer vision.
In digital geometry, the notion of blurred segment \cite{Debled05,Buzer07}
In digital geometry, the notion of blurred segment \cite{DebledAl05,Buzer07}
was introduced to cope with the image noise or other sources of
imperfections from the real world.
imperfections from the real world. The pre-image of that geometrical object,
ie the space of geometric entities which numerization matches this
blurred segment, may convey useful information to evaluate possible moves in
the 3D interpretations drawn, as a promising extension of former works
on discrete epipolar geometry \cite{NatsumiAl08}.
Our work aims at designing a flexible tool to detect such blurred segment
in gray-level images for as well supervised as unsupervised contexts.
......
......@@ -15,8 +15,9 @@
\begin{document}
\begin{frontmatter}
\title{Straight edge detection
based on an adaptive directional tracking of blurred segments}
% \title{Straight edge detection
% based on adaptive directional tracking of blurred segments}
\title{Adaptive directional tracking of blurred segments}
\author{Philippe Even\inst{1} \and
Phuc Ngo\inst{1} \and
......
......@@ -16,29 +16,34 @@ When $\nu = max (|a|, |b|)$, $\mathcal{D}$ is the narrowest 8-connected
line and is called a naive line.
\begin{definition}
A blurred segment of assigned width $\epsilon$ is a set $\mathcal{S}_\epsilon$
of points in $\mathbb{Z}^2$ that all belong to a digital line of arithmetical
width $\epsilon$.
A blurred segment $\mathcal{B}$ of assigned width $\varepsilon$ is a set
$\mathcal{S}_\varepsilon$ of points in $\mathbb{Z}^2$ that all belong
to a digital line of arithmetical width $\varepsilon$.
\end{definition}
Linear time algorithms have been developed to recognize a blurred segment
of assigned width $\epsilon$ \cite{DebledAl05,Buzer07}.
of assigned width $\varepsilon$ \cite{DebledAl05,Buzer07}.
They are based on an incremental growth of the convex hull of the blurred
segment when adding each point successively.
The minimal width $\mu$ of the blurred segment is the minimal width of
this convex hull as computed by Melkman's algorithm \cite{Melkman87}.
The extension of the blurred segment with a new input point is controlled
by the recognition test $\mu < \epsilon$.
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}.
The extension of the blurred segment with a new input point is thus
controlled by the recognition test $\mu < \varepsilon$.
\begin{figure}[h]
\center
\begin{picture}(300,40)
\end{picture}
\caption{Example of blurred segment and recognition problem.}
\input{Fig_notions/bswidth}
\caption{A growing blurred segment $\mathcal{B}$ :
when adding the new point $P'$, the blurred segment minimal width augments
from $\mu$ to $\mu '$; if the new width $\mu '$ exceeds the assigned width
$\varepsilon$, then the new input point is rejected.}
\label{fig:bs}
\end{figure}
At the beginning, a large width $\epsilon_{ini}$ is assigned to the
At the beginning, a large width $\varepsilon_{ini}$ is assigned to the
recognition problem to allow the detection of large blurred segments.
Then, when extending the blurred segment, this assigned width is
gradually decremented to reach the detected blurred segment minimal width.
......
0% Loading or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment