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	<title>Lab Vision3D</title>
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	<link>http://vision3d.iro.umontreal.ca</link>
	<description>Université de Montréal</description>
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		<title>Le cinéma omnistéréo ou l&#8217;art d&#8217;avoir des yeux tout le tour de la tête (thesis)</title>
		<link>http://vision3d.iro.umontreal.ca/en/blog/2012/06/22/le-cinema-omnistereo-ou-lart-davoir-des-yeux-tout-le-tour-de-la-tete-thesis/</link>
		<comments>http://vision3d.iro.umontreal.ca/en/blog/2012/06/22/le-cinema-omnistereo-ou-lart-davoir-des-yeux-tout-le-tour-de-la-tete-thesis/#comments</comments>
		<pubDate>Fri, 22 Jun 2012 13:26:50 +0000</pubDate>
		<dc:creator>Vincent Chapdelaine-Couture</dc:creator>
				<category><![CDATA[Ph.D.]]></category>
		<category><![CDATA[Vincent Couture]]></category>

		<guid isPermaLink="false">http://vision3d.iro.umontreal.ca/?p=3062</guid>
		<description><![CDATA[Vincent Chapdelaine-Couture. Omnistereo cinema: capture, projection and perception, thesis accepted on the 24th of April, 2012. Abstract This thesis deals with aspects of shooting, projection and perception of stereo panoramic cinema, also called omnistereo cinema. It falls largely in the &#8230; <a href="http://vision3d.iro.umontreal.ca/en/blog/2012/06/22/le-cinema-omnistereo-ou-lart-davoir-des-yeux-tout-le-tour-de-la-tete-thesis/">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p><span>Vincent Chapdelaine-Couture. <strong>Omnistereo cinema: capture, projection and perception</strong>, thesis accepted on the 24th of April, 2012.</span><span id="more-3062"></span></p>
<h3>Abstract</h3>
<p>This thesis deals with aspects of shooting, projection and perception of stereo panoramic cinema, also called omnistereo cinema. It falls largely in the field of computer vision, but it also in the areas of computer graphics and human visual perception.</p>
<p>Omnistereo cinema uses immersive screens to project videos that provide depth information of a scene all around the spectators. Many challenges remain in omnistereo cinema, in particular<br />
shooting omnistereo videos for dynamic scenes, polarized projection on highly reflective screens making difficult the process to recover their shape by active reconstruction, and perception of depth distortions introduced by omnistereo images.</p>
<p>Our thesis addressed these challenges by making three major contributions. First, we developed the first mosaicing method of omnistereo videos for stochastic and localized motions. We developed a psychophysical experiment that shows the effectiveness of the method for scenes without isolated structure, such as water flows. We also propose a shooting method that adds to these videos foreground motions that are not as constrained, like a moving actor. Second, we introduced new light patterns that allow a camera and a projector to recover the shape of objects likely to produce interreflections. These patterns are general enough to not only recover the shape of omnistereo screens, but also very complex objects that have depth discontinuities from the viewpoint of the camera. Third, we showed that omnistereo distortions are negligible for a viewer located at the center of a cylindrical screen, as they are in the periphery of the visual field where the human visual system becomes less accurate.</p>
<h3>Document</h3>
<ul>
<li><a href="http://www-etud.iro.umontreal.ca/~chapdelv/pdf/couture-thesis.pdf">couture-thesis.pdf</a></li>
</ul>
]]></content:encoded>
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		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Unstructured Light Scanning to Overcome Interreflections</title>
		<link>http://vision3d.iro.umontreal.ca/en/blog/2011/11/05/unstructured-light-scanning-overcome-interreflections/</link>
		<comments>http://vision3d.iro.umontreal.ca/en/blog/2011/11/05/unstructured-light-scanning-overcome-interreflections/#comments</comments>
		<pubDate>Sat, 05 Nov 2011 15:37:37 +0000</pubDate>
		<dc:creator>Vincent Chapdelaine-Couture</dc:creator>
				<category><![CDATA[ICCV]]></category>
		<category><![CDATA[Nicolas Martin]]></category>
		<category><![CDATA[Sébastien Roy]]></category>
		<category><![CDATA[Uncategorized]]></category>
		<category><![CDATA[Vincent Couture]]></category>
		<category><![CDATA[scan]]></category>
		<category><![CDATA[unstructured light]]></category>

		<guid isPermaLink="false">http://vision3d.iro.umontreal.ca/?p=3033</guid>
		<description><![CDATA[V. Couture, N. Martin, S. Roy. Unstructured Light Scanning to Overcome Interreflections, International Conference on Computer Vision (ICCV), 2011. Abstract Reconstruction from structured light can be greatly affected by interreflections between surfaces in the scene. This paper introduces band-pass white &#8230; <a href="http://vision3d.iro.umontreal.ca/en/blog/2011/11/05/unstructured-light-scanning-overcome-interreflections/">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p><span>V. Couture, N. Martin, S. Roy. <strong>Unstructured Light Scanning to Overcome Interreflections</strong>,  International Conference on Computer Vision (ICCV), 2011.</span><span id="more-3033"></span></p>
<h3>Abstract</h3>
<p>Reconstruction from structured light can be greatly affected by interreflections between surfaces in the scene. This paper introduces band-pass white noise patterns designed specifically to reduce interreflections, and still be robust to standard challenges in scanning systems such as scene depth discontinuities, defocus and low camera-projector pixel ratio. While this approach uses unstructured light patterns that increase the number of required projected images, it is up to our knowledge the first method that is able to recover scene disparities in the presence of both scene discontinuities and interreflections. Furthermore, the method does not require calibration (geometric nor photometric) or post-processing such as dynamic programming or phase unwrapping. We show results for a challenging scene and compare them to correspondences obtained with the well-known Gray code and Phase-shift methods.</p>
<h3>Document</h3>
<ul>
<li><a href="http://www-etud.iro.umontreal.ca/~chapdelv/pdf/couture-iccv2011-omnistereo.pdf">couture-iccv2011-omnistereo.pdf</a></li>
</ul>
]]></content:encoded>
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		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Panoramic Stereo Video Textures</title>
		<link>http://vision3d.iro.umontreal.ca/en/blog/2011/11/04/panoramic-stereo-video-textures/</link>
		<comments>http://vision3d.iro.umontreal.ca/en/blog/2011/11/04/panoramic-stereo-video-textures/#comments</comments>
		<pubDate>Sat, 05 Nov 2011 01:09:37 +0000</pubDate>
		<dc:creator>Vincent Chapdelaine-Couture</dc:creator>
				<category><![CDATA[ICCV]]></category>
		<category><![CDATA[Michael Langer]]></category>
		<category><![CDATA[Sébastien Roy]]></category>
		<category><![CDATA[Vincent Couture]]></category>
		<category><![CDATA[omnistéréo]]></category>

		<guid isPermaLink="false">http://vision3d.iro.umontreal.ca/?p=3005</guid>
		<description><![CDATA[V. Couture, M.S. Langer, S. Roy. Panoramic Stereo Video Textures, International Conference on Computer Vision (ICCV), 2011. Abstract A panoramic stereo (or omnistereo) pair of images provides depth information from stereo up to 360 degrees around a central observer. Because &#8230; <a href="http://vision3d.iro.umontreal.ca/en/blog/2011/11/04/panoramic-stereo-video-textures/">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p><span>V. Couture, M.S. Langer, S. Roy. <strong>Panoramic Stereo Video Textures</strong>,  International Conference on Computer Vision (ICCV), 2011.</span><span id="more-3005"></span></p>
<h3>Abstract</h3>
<p>A panoramic stereo (or omnistereo) pair of images provides depth<br />
information from stereo up to 360 degrees around a central observer.<br />
Because omnistereo lenses or mirrors do not yet exist, synthesizing<br />
omnistereo images requires multiple stereo camera positions and<br />
baseline orientations.  Recent omnistereo methods stitch together<br />
many small field of view images called slits which are captured by<br />
one or two cameras following a circular motion.  However, these<br />
methods produce omnistereo images for static scenes only.  The<br />
situation is much more challenging for dynamic scenes since<br />
stitching needs to occur over both space and time and should<br />
synchronize the motion between left and right views as much as<br />
possible.<br />
This paper presents the first ever method for synthesizing panoramic<br />
stereo video textures.  The method uses full frames rather than<br />
slits and uses blending across seams rather than smoothing or<br />
matching based on   graph cuts.  The method produces loopable panoramic<br />
stereo videos that can be displayed up to 360 degrees around a<br />
viewer.</p>
<h3>Document</h3>
<ul>
<li><a href="http://www-etud.iro.umontreal.ca/~chapdelv/pdf/couture-iccv2011-omnistereo.pdf">couture-iccv2011-omnistereo.pdf</a></li>
</ul>
]]></content:encoded>
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		<slash:comments>0</slash:comments>
		</item>
		<item>
		<title>Experimentation with mobile camera-projector system</title>
		<link>http://vision3d.iro.umontreal.ca/en/blog/2011/06/08/experimentation-with-mobile-camera-projector-system/</link>
		<comments>http://vision3d.iro.umontreal.ca/en/blog/2011/06/08/experimentation-with-mobile-camera-projector-system/#comments</comments>
		<pubDate>Wed, 08 Jun 2011 23:06:37 +0000</pubDate>
		<dc:creator>Nicolas Martin</dc:creator>
				<category><![CDATA[Uncategorized]]></category>

		<guid isPermaLink="false">http://vision3d.iro.umontreal.ca/?p=2824</guid>
		<description><![CDATA[Sorry, this entry is only available in Français.]]></description>
			<content:encoded><![CDATA[<p>Sorry, this entry is only available in <a href="http://vision3d.iro.umontreal.ca/feed/">Français</a>.</p>
]]></content:encoded>
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		<slash:comments>1</slash:comments>
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		</item>
		<item>
		<title>Easy multi-projector desktop</title>
		<link>http://vision3d.iro.umontreal.ca/en/blog/2011/05/11/easy-multi-projector-desktop/</link>
		<comments>http://vision3d.iro.umontreal.ca/en/blog/2011/05/11/easy-multi-projector-desktop/#comments</comments>
		<pubDate>Wed, 11 May 2011 14:10:55 +0000</pubDate>
		<dc:creator>boucl</dc:creator>
				<category><![CDATA[Lighttwist]]></category>
		<category><![CDATA[Linux]]></category>

		<guid isPermaLink="false">http://vision3d.iro.umontreal.ca/?p=2736</guid>
		<description><![CDATA[Introducing a new an easy way to create a single high-resolution Linux desktop using multiple projectors.  Anyone can achieve this with the following easy-to-use tools: lt-align: the LightTwist projector alignment tool is a simple point-and-click interface that lets the user &#8230; <a href="http://vision3d.iro.umontreal.ca/en/blog/2011/05/11/easy-multi-projector-desktop/">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p>Introducing a new an easy way to create a single high-resolution Linux desktop using multiple projectors.  Anyone can achieve this with the following easy-to-use tools:</p>
<p><strong>lt-align</strong>: the LightTwist projector alignment tool is a simple point-and-click interface that lets the user specify a single projection area with multiple overlapping projectors and generate distortion and blending maps.</p>
<p><strong>lt-compiz-plugin</strong>: A plugin for Compiz 0.9x that warps and blends the output of your projectors using the deformation maps produced by lt-align, creating one single seamless high resolution desktop area.</p>
<h2 class="wp-caption-text"><span id="more-2736"></span></h2>
<h2 class="wp-caption-text">Requirements</h2>
<hr />
<p>The LightTwist projector alignment tool and compiz plugin have a few dependencies which must be met.  It has been developed on Ubuntu 11.04 which includes Compiz 0.9 in its distribution.</p>
<p>The plugin cannot be used with Compiz versions prior to 0.9x.</p>
<p>Ubuntu 11.04 users can simply execute the following command:</p>
<pre>sudo apt-get install subversion cmake cmake-curses-gui libpng12-dev\
 libnetpbm10-dev libavcodec-dev libavformat-dev libavutil-dev\
 libswscale-dev libcv-dev libcvaux-dev libhighgui-dev libfftw3-dev\
 libopenscenegraph-dev libboost-dev libboost-serialization-dev\
 compiz-dev compizconfig-settings-manager xsltproc</pre>
<p>For earlier releases of Ubuntu and other distributions, you can get the latest version of Compiz on their website: www.compiz.org</p>
<p>&nbsp;</p>
<p>&nbsp;</p>
<h2>Downloads and installation</h2>
<hr />
<p><span style="text-decoration: underline">IMGU</span></p>
<p>IMGU is our extensive image manipulation library, which is used in both the plugin and the projector alignment tool.</p>
<p>First, checkout the source using subversion:</p>
<pre>svn co https://svn3d.iro.umontreal.ca/svn/imgu/devel imgu</pre>
<p>then go to the newly created directory and build the library:</p>
<pre>cd imgu
cmake .
make
sudo make install</pre>
<p>&nbsp;</p>
<h3><span style="text-decoration: underline">lt-align</span></h3>
<p>Download, compile and install lt-align:</p>
<pre>mkdir ~/svn3d
cd ~/svn3d
svn co https://svn3d.iro.umontreal.ca/svn/vision3d/lt-align
cd lt-align
cmake .
make
sudo make install</pre>
<p>&nbsp;</p>
<p><span style="text-decoration: underline"> </span></p>
<p>&nbsp;</p>
<h3><span style="text-decoration: underline">lt-compiz-plugin</span></h3>
<p>Download, compile and install lt-compiz-plugin (Compiz plugins cannot be built from the base directory.  You must create a &#8216;build&#8217; directory and compile from there):</p>
<pre>mkdir ~/svn3d
cd ~/svn3d
svn co https://svn3d.iro.umontreal.ca/svn/vision3d/lt-compiz-plugin
cd lt-compiz-plugin
mkdir build
cd build
cmake ..
make
make install     ## no sudo!  it will be installed
                 ## in .compiz-1/ in your home directory</pre>
<p>&nbsp;</p>
<h2>How to use lt-align</h2>
<h3>
<hr />
</h3>
<p><object   type="application/x-shockwave-flash"  data="http://www.youtube.com/v/yjxWPenp54w?fs=1&amp;feature=oembed?fs=1"  width="640"  height="360"><param name="movie" value="http://www.youtube.com/v/yjxWPenp54w?fs=1&amp;feature=oembed?fs=1" /><param name="quality" value="high" /><param name="allowFullScreen" value="true" /><param name="allowScriptAccess" value="always" /><param name="pluginspage" value="http://www.macromedia.com/go/getflashplayer" /><param name="autoplay" value="false" /><param name="autostart" value="false" /><param name="wmode" value="transparent" /><param name="flashvars" value="" /><a href="http://www.youtube.com/watch?v=yjxWPenp54w">http://www.youtube.com/watch?v=yjxWPenp54w</a> </object></p>
<h3><span style="text-decoration: underline">command line options</span></h3>
<p><span style="text-decoration: underline"><br />
</span></p>
<pre>$lt-align -h

LightTwist projector alignment tool
Version 0.1

Usage:
-h                                     Displays this help message
-screen&lt;n&gt; &lt;x0&gt; &lt;y0&gt; &lt;width&gt; &lt;height&gt;  Defines a screen and its
                                       dimensions
-o &lt;filename&gt;                          Saves setup to file
-i &lt;filename&gt;                          Loads setup from file
                                       (overrides -screen args)
no arguments                           Uses Xinerama to initialize
                                       all screens</pre>
<h3><span style="text-decoration: underline">Controls</span></h3>
<p>&nbsp;</p>
<p>&lt;PageUp&gt; or &lt;PageDn&gt;  : Cycle through all overlaps.  Pairs of projectors will become blue. When no projector pair is selected, you may define/adjust the four white crosshairs defining your desired projection area.</p>
<p>&lt;space&gt; Deselect current projector pair, so you can edit your desired projection area (white crosshairs).</p>
<p>Keys &lt;1&gt; and &lt;2&gt;:  Select which of the two screens of the current overlap you wish to define/modify points.</p>
<p>Arrow keys: subpixel adjustment.</p>
<p>&lt;s&gt;: Save setup and generate distortion maps.</p>
<p>&lt;ESC&gt;: quit.</p>
<h3><span style="text-decoration: underline">Instructions</span></h3>
<p>&nbsp;</p>
<p>1 &#8211; Define the desired projection area:</p>
<p>Make sure no projector pair is selected (press &lt;space&gt;).<br />
Click on the four full screen corners (left top, right top, right bottom, left bottom)</p>
<p>2 &#8211; Specifiy matching points for each projector overlap</p>
<p>First, press &lt;PageDn&gt; to select the first projector pair.  If they do not overlap on the projection surface, continue cycling with &lt;PageDn&gt;.  When you have selected a pair of projectors that do overlap, click on 4 points in the first screen WITHIN the overlapping zone.</p>
<p>Then press &lt;2&gt; to select the second projector of the overlap pair.  Now, click on the same 4 points, but in the second screen.  Be as precise as you can.  The crosshairs with 2 circles should be together.  Since the crosshairs and lines in the first screen are red, and green in the second screen, the crosshairs and lines will turn yellow if they are well aligned.</p>
<p>You may make sub-pixel adjustments to a crosshair&#8217;s positions with the arrow keys while the mouse points hovers over it.</p>
<p>Do this for every pair of overlapping projectors, until lines appear connecting the 4 white crosshairs defining your desired projection area.</p>
<p>When you are satisfied with your alignment, press &lt;s&gt; to save your setup and generate your distortion maps.</p>
<p>You may now use those maps with the LightTwist Compiz plugin</p>
<p>&nbsp;</p>
<h2>How to use lt-compiz-plugin</h2>
<hr />
<p>First of all you must manually restart compiz un a terminal:</p>
<pre>compiz --replace ccp</pre>
<p>The default Ubuntu installation does not include the &#8216;ccp&#8217; option when launching Compiz at startup.  Without the &#8216;ccp&#8217; option, Compiz will not load the LightTwist plugin at all.  Until that is fixed, you will have to manually restart Compiz every time you want to use th plugin.</p>
<h3><span style="text-decoration: underline">Enabling the plugin</span></h3>
<p>Start the CompizConfig Settings manager from the System&gt;Preference menu, or start it from a terminal by typing &#8216;ccsm&#8217;.</p>
<p>Go to the Utility section, to the Mouse Position Polling and set the Mouse Poll Interval to 1 (default value is 40)</p>
<p><a href="http://vision3d.iro.umontreal.ca/wp-content/uploads/2011/05/Screenshot-CompizConfig-Settings-Manager-2.png"><img class="alignnone size-medium wp-image-2751" src="http://vision3d.iro.umontreal.ca/wp-content/uploads/2011/05/Screenshot-CompizConfig-Settings-Manager-2-300x188.png" alt="" width="300" height="188" /></a></p>
<p>Go to Effects section. Enable the lighttwist plugin</p>
<p>Locate the fragment shader : set it to</p>
<pre>&lt;your home directory&gt;/.compiz-1/lighttwist/data/deform.frag</pre>
<p>Leave the vertex shader field empty.</p>
<p>Now enter the distortion maps and parameters for each screen:</p>
<p>click &#8220;New&#8221;</p>
<p>In the Edit window:<br />
Lut: select the lut_&lt;n&gt;.png file generated for each projector<br />
Blend :  (leave empty)<br />
Blend embeded : checked<br />
Proj num : set it to the projector number &lt;n&gt;<br />
Gamma : set to 1 initially.  You may adjust it to your liking afterwards</p>
<p>Your settings should look something like this:</p>
<p><a href="http://vision3d.iro.umontreal.ca/wp-content/uploads/2011/05/Screenshot-CompizConfig-Settings-Manager-1.png"><img class="alignnone size-medium wp-image-2750" src="http://vision3d.iro.umontreal.ca/wp-content/uploads/2011/05/Screenshot-CompizConfig-Settings-Manager-1-300x188.png" alt="" width="300" height="188" /></a></p>
<p>And now you are ready to activate the LightTwist Compiz plugin!  Simply use the following hot keys:</p>
<p>&lt;shift&gt;F9    : activate/deactivate plugin<br />
&lt;shift&gt;F7    : activate/deactivate deformation</p>
<p>&#8230; and enjoy!</p>
<p>&nbsp;</p>
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		</item>
		<item>
		<title>Connexion VPN Juniper à l&#8217;Université de Montréal (Linux Ubuntu)</title>
		<link>http://vision3d.iro.umontreal.ca/en/blog/2011/05/06/connexion-vpn-juniper-a-luniversite-de-montreal-linux-ubuntu/</link>
		<comments>http://vision3d.iro.umontreal.ca/en/blog/2011/05/06/connexion-vpn-juniper-a-luniversite-de-montreal-linux-ubuntu/#comments</comments>
		<pubDate>Fri, 06 May 2011 14:06:19 +0000</pubDate>
		<dc:creator>Sébastien Roy</dc:creator>
				<category><![CDATA[Linux]]></category>
		<category><![CDATA[Université de Montréal]]></category>
		<category><![CDATA[VPN]]></category>

		<guid isPermaLink="false">http://vision3d.iro.umontreal.ca/?p=2528</guid>
		<description><![CDATA[Sorry, this entry is only available in Français.]]></description>
			<content:encoded><![CDATA[<p>Sorry, this entry is only available in <a href="http://vision3d.iro.umontreal.ca/feed/">Français</a>.</p>
]]></content:encoded>
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		<slash:comments>15</slash:comments>
		</item>
		<item>
		<title>Libre Graphics Meeting (LGM 2011)</title>
		<link>http://vision3d.iro.umontreal.ca/en/blog/2011/05/03/libre-graphics-meeting-lgm-2011/</link>
		<comments>http://vision3d.iro.umontreal.ca/en/blog/2011/05/03/libre-graphics-meeting-lgm-2011/#comments</comments>
		<pubDate>Tue, 03 May 2011 10:41:51 +0000</pubDate>
		<dc:creator>Sébastien Roy</dc:creator>
				<category><![CDATA[Événement]]></category>
		<category><![CDATA[Lighttwist]]></category>
		<category><![CDATA[Linux]]></category>

		<guid isPermaLink="false">http://vision3d.iro.umontreal.ca/?p=2694</guid>
		<description><![CDATA[The next Libre Graphics Meeting 2011 will be held on may 10-13. We will present a démo of a new compiz plugin &#8220;Lighttwist&#8221; which will significantly raise the screen resolution of the Linux desktop by using multiple projectors. The image &#8230; <a href="http://vision3d.iro.umontreal.ca/en/blog/2011/05/03/libre-graphics-meeting-lgm-2011/">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p><a href="http://vision3d.iro.umontreal.ca/wp-content/uploads/2011/05/LGM.png"><img class="alignright size-full wp-image-2696" src="http://vision3d.iro.umontreal.ca/wp-content/uploads/2011/05/LGM.png" alt="" width="250" height="278" /></a>The next <a title="LGM 2011" href="http://www.libregraphicsmeeting.org/2011/">Libre Graphics Meeting 2011</a> will be held on may 10-13.</p>
<p>We will present a démo of a new <a title="Desktop multi-projecteur facile" href="http://vision3d.iro.umontreal.ca/blog/2011/05/11/desktop-multi-projecteur-facile/">compiz plugin &#8220;Lighttwist&#8221;</a> which will significantly raise the screen resolution of the Linux desktop by using multiple projectors. The image alignment is very simple and accurate, and edge-blending is automatic. The code will be GPL and made available on the day of the presentation at LGM.</p>
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		<title>Connexion à Eduroam</title>
		<link>http://vision3d.iro.umontreal.ca/en/blog/2010/07/12/connexion-a-eduroam/</link>
		<comments>http://vision3d.iro.umontreal.ca/en/blog/2010/07/12/connexion-a-eduroam/#comments</comments>
		<pubDate>Mon, 12 Jul 2010 19:02:29 +0000</pubDate>
		<dc:creator>admin</dc:creator>
				<category><![CDATA[Linux]]></category>
		<category><![CDATA[Université de Montréal]]></category>

		<guid isPermaLink="false">http://vision3d.iro.umontreal.ca/?p=2382</guid>
		<description><![CDATA[Sorry, this entry is only available in Français.]]></description>
			<content:encoded><![CDATA[<p>Sorry, this entry is only available in <a href="http://vision3d.iro.umontreal.ca/feed/">Français</a>.</p>
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		<title>Analysis of Disparity Distortions in Omnistereoscopic Displays</title>
		<link>http://vision3d.iro.umontreal.ca/en/blog/2010/07/12/analysis-of-disparity-distortions-in-omnistereoscopic-displays/</link>
		<comments>http://vision3d.iro.umontreal.ca/en/blog/2010/07/12/analysis-of-disparity-distortions-in-omnistereoscopic-displays/#comments</comments>
		<pubDate>Mon, 12 Jul 2010 15:39:24 +0000</pubDate>
		<dc:creator>Vincent Chapdelaine-Couture</dc:creator>
				<category><![CDATA[Omnistéréo]]></category>
		<category><![CDATA[Sébastien Roy]]></category>
		<category><![CDATA[TAP]]></category>
		<category><![CDATA[Vincent Couture]]></category>
		<category><![CDATA[environnement immersif]]></category>
		<category><![CDATA[omnistéréo]]></category>
		<category><![CDATA[perception]]></category>

		<guid isPermaLink="false">http://vision3d.iro.umontreal.ca/?p=2375</guid>
		<description><![CDATA[V. Couture, M.S. Langer, S. Roy. Analysis of Disparity Distortions in Omnistereoscopic Displays, ACM Transactions on Applied Perception, vol. 7 (4), 2010. Abstract An omnistereoscopic image is a pair of panoramic images that enables stereoscopic depth perception all around an &#8230; <a href="http://vision3d.iro.umontreal.ca/en/blog/2010/07/12/analysis-of-disparity-distortions-in-omnistereoscopic-displays/">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<p><span>V. Couture, M.S. Langer, S. Roy. <strong>Analysis of Disparity Distortions in Omnistereoscopic Displays</strong>,  ACM Transactions on Applied Perception, vol. 7 (4), 2010.</span><span id="more-2375"></span></p>
<h3>Abstract</h3>
<p>An omnistereoscopic image is a pair of panoramic images that enables stereoscopic depth perception all around an observer. An omnistereo projection on a cylindrical display does not require tracking of the observer’s viewing direction. However, such a display introduces stereo distortions. In this article, we investigate two projection models for rendering 3D scenes in omnistereo. The first is designed to give zero disparity errors at the center of the visual field. The second is the well-known slit-camera model. For both models, disparity errors are shown to increase gradually in the periphery, as visual stereo acuity decreases. We use available data on human stereoscopic acuity limits to argue that depth distortions caused by these models are so small that they cannot be perceived.</p>
<h3>Document</h3>
<ul>
<li><a href="http://www-etud.iro.umontreal.ca/~chapdelv/pdf/couture-tap2010.pdf">couture-tap2010.pdf</a></li>
</ul>
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		<title>Capturing Non-Periodic Omnistereo Motion</title>
		<link>http://vision3d.iro.umontreal.ca/en/blog/2010/07/01/non-periodic-omnistereo-motion/</link>
		<comments>http://vision3d.iro.umontreal.ca/en/blog/2010/07/01/non-periodic-omnistereo-motion/#comments</comments>
		<pubDate>Thu, 01 Jul 2010 15:30:21 +0000</pubDate>
		<dc:creator>Vincent Chapdelaine-Couture</dc:creator>
				<category><![CDATA[Michael Langer]]></category>
		<category><![CDATA[Omnistéréo]]></category>
		<category><![CDATA[OMNIVIS]]></category>
		<category><![CDATA[Sébastien Roy]]></category>
		<category><![CDATA[Vincent Couture]]></category>
		<category><![CDATA[calibration]]></category>
		<category><![CDATA[omnidirectionnel]]></category>
		<category><![CDATA[omnistéréo]]></category>

		<guid isPermaLink="false">http://vision3d.iro.umontreal.ca/?p=2372</guid>
		<description><![CDATA[Abstract An omnistereo pair of images enables depth perception all around the observer. Because omnistereo lenses or mirrors do not yet exist, capturing an omnistereo video would require using several stereo cameras at different baseline orientations. This paper presents a &#8230; <a href="http://vision3d.iro.umontreal.ca/en/blog/2010/07/01/non-periodic-omnistereo-motion/">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description>
			<content:encoded><![CDATA[<h3><a href="http://vision3d.iro.umontreal.ca/wp-content/uploads/2010/07/omnicalib.png"><img class="alignright size-full wp-image-2664" src="http://vision3d.iro.umontreal.ca/wp-content/uploads/2010/07/omnicalib.png" alt="" width="308" height="276" /></a>Abstract</h3>
<p>An omnistereo pair of images enables depth perception all around the observer. Because omnistereo lenses or mirrors do not yet exist, capturing an omnistereo video would require using several stereo cameras at different baseline orientations. This paper presents a multi-take capture method for creating high-resolution omnistereo videos at an affordable cost: only two standard cameras and a tripod are required. The method combines multiple stereo takes, where each take follows some action within the field of view, an actor for instance. Internal camera parameters are first calibrated by capturing a static omnistereo background. Each frame of each take is then pasted on the background at a position estimated by feature tracking. The paper provides a detailed description of the steps of the method. It also provides an analysis of parallax which results from the off-axis camera rotation. Parameters for the method are chosen to minimize artifacts that arise from this parallax. The method is intended to be applied in a relatively controlled space like a movie set, where the action in each take is within the field of view of the cameras.</p>
<p><span id="more-2372"></span></p>
<h3>Reference</h3>
<p><span>V. Couture, M.S. Langer, S. Roy. <strong>Capturing Non-Periodic Omnistereo Motions</strong>, 10th Workshop on Omnidirectional Vision, Camera Networds and Non-classical Cameras (OMNIVIS), June 2010, Zaragoza, Spain.</span></p>
<h3>Document</h3>
<ul>
<li><a href="http://www-etud.iro.umontreal.ca/~chapdelv/pdf/couture-omnivis2010.pdf">couture-omnivis2010.pdf</a></li>
</ul>
<ul></ul>
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