{"id":1991,"date":"2014-02-05T17:32:40","date_gmt":"2014-02-05T17:32:40","guid":{"rendered":"https:\/\/www.anagram.at\/en\/diplomarbeit\/epipolar-geometry\/"},"modified":"2014-02-05T17:32:40","modified_gmt":"2014-02-05T17:32:40","slug":"epipolar-geometry","status":"publish","type":"page","link":"https:\/\/www.anagram.at\/en\/diplomarbeit\/epipolar-geometry\/","title":{"rendered":"Epipolar Geometry"},"content":{"rendered":"<p><body><br \/>\n<!--Navigation Panel--><br \/>\n<b> Next:<\/b> <a name=\"tex2html317\" href=\"https:\/\/www.anagram.at\/diplomarbeit\/fundamental-matrix\/\">Fundamental Matrix<\/a><br \/>\n<b> Up:<\/b> <a name=\"tex2html313\" href=\"https:\/\/www.anagram.at\/diplomarbeit\/stereo-geometry\/\">Stereo Geometry<\/a><br \/>\n<b> Previous:<\/b> <a name=\"tex2html307\" href=\"https:\/\/www.anagram.at\/diplomarbeit\/stereo-geometry\/\">Stereo Geometry<\/a><br \/>\n<!--End of Navigation Panel--><\/p>\n<h2><a name=\"SECTION00331000000000000000\"\/> <a name=\"epipolargeometry\"\/><\/p>\n<p>Epipolar Geometry<br \/>\n<\/h2>\n<p>The epipolar geometry is the intrinsic projective geometry between two views. It is independent of scene structure, and only depends on the camera&#8217;s internal parameters and relative pose. The <i>fundamental matrix<\/i> <img loading=\"lazy\" width=\"19\" height=\"16\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img89.png\" alt=\"$ F$\"\/> encapsulates this intrinsic geometry. It is a <img loading=\"lazy\" width=\"34\" height=\"19\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img90.png\" alt=\"$ 3 x 3$\"\/> matrix of rank 2. If a point <img loading=\"lazy\" width=\"22\" height=\"16\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img91.png\" alt=\"$ X$\"\/> in space is mapped to one image as <img loading=\"lazy\" width=\"23\" height=\"33\" align=\"MIDDLE\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img92.png\" alt=\"$ x_1$\"\/>, and to the second image as <img loading=\"lazy\" width=\"23\" height=\"33\" align=\"MIDDLE\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img93.png\" alt=\"$ x_2$\"\/>, then the image points satisfy the relation <!-- MATH\n $x_2^TFx_1=0$\n --><br \/>\n<img loading=\"lazy\" width=\"93\" height=\"40\" align=\"MIDDLE\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img94.png\" alt=\"$ x_2^TFx_1=0$\"\/>. <img loading=\"lazy\" width=\"19\" height=\"16\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img89.png\" alt=\"$ F$\"\/> can be computed if both camera parameters are known. More about this in Section <a href=\"https:\/\/www.anagram.at\/diplomarbeit\/fundamental-matrix\/#fundamentalmatrix\">2.3.2<\/a>. <\/p>\n<p>The relation between a projected point <img loading=\"lazy\" width=\"23\" height=\"33\" align=\"MIDDLE\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img92.png\" alt=\"$ x_1$\"\/> in one&#8217;s view and its corresponding point <img loading=\"lazy\" width=\"23\" height=\"33\" align=\"MIDDLE\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img93.png\" alt=\"$ x_2$\"\/> in the other view can be described geometrically. In Figure <a href=\"#epipolargeometry_img\">2.7<\/a>, we can see that for every point <img loading=\"lazy\" width=\"23\" height=\"33\" align=\"MIDDLE\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img92.png\" alt=\"$ x_1$\"\/> a corresponding line, on which <img loading=\"lazy\" width=\"23\" height=\"33\" align=\"MIDDLE\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img93.png\" alt=\"$ x_2$\"\/> can be found, exists. These lines are called <i>epipolar lines<\/i>. The intersection between the baseline <img loading=\"lazy\" width=\"13\" height=\"20\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img13.png\" alt=\"$ b$\"\/> and the image planes is called <i>epipole<\/i>. All epipolar lines intersect at the epipole. <\/p>\n<div align=\"CENTER\"><a name=\"epipolargeometry_img\"\/><a name=\"465\"\/><\/p>\n<table>\n<caption align=\"BOTTOM\"><strong>Figure 2.7:<\/strong><br \/>\nEpipolar Geometry, <img loading=\"lazy\" width=\"13\" height=\"19\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img5.png\" alt=\"$ e$\"\/> and <img loading=\"lazy\" width=\"18\" height=\"17\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img6.png\" alt=\"$ e'$\"\/> are the epipoles, <img loading=\"lazy\" width=\"11\" height=\"20\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img7.png\" alt=\"$ l$\"\/> and <img loading=\"lazy\" width=\"15\" height=\"17\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img8.png\" alt=\"$ l'$\"\/> are the epipolar lines, <img loading=\"lazy\" width=\"19\" height=\"16\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img9.png\" alt=\"$ O$\"\/> and <img loading=\"lazy\" width=\"24\" height=\"17\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img10.png\" alt=\"$ O'$\"\/> are the projection centers<\/caption>\n<tr>\n<td>\n<div align=\"CENTER\">\n <img loading=\"lazy\" width=\"685\" height=\"284\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/epipolargeometry.jpg\" alt=\"Image epipolargeometry\"\/><\/div>\n<\/td>\n<\/tr>\n<\/table>\n<\/div>\n<p>\nIf a point <img loading=\"lazy\" width=\"19\" height=\"16\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img84.png\" alt=\"$ P$\"\/> in space is known, the corresponding epipolar lines can be found by computing the intersection between the two image planes, and the plane that is formed by the baseline <img loading=\"lazy\" width=\"13\" height=\"20\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img13.png\" alt=\"$ b$\"\/> and the line from the optical center <img loading=\"lazy\" width=\"19\" height=\"16\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img9.png\" alt=\"$ O$\"\/> to the point <img loading=\"lazy\" width=\"19\" height=\"16\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img84.png\" alt=\"$ P$\"\/>. In Figure <a href=\"#epipolargeometry_img\">2.7<\/a> the epipolar lines are denoted by <img loading=\"lazy\" width=\"11\" height=\"20\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img7.png\" alt=\"$ l$\"\/> and <img loading=\"lazy\" width=\"15\" height=\"17\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img8.png\" alt=\"$ l'$\"\/>. Supposing now that we know only <img loading=\"lazy\" width=\"22\" height=\"33\" align=\"MIDDLE\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img95.png\" alt=\"$ p_1$\"\/>, we may ask how the corresponding point <img loading=\"lazy\" width=\"22\" height=\"33\" align=\"MIDDLE\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img96.png\" alt=\"$ p_2$\"\/> can be found. The plane <img loading=\"lazy\" width=\"19\" height=\"16\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img97.png\" alt=\"$ Pi$\"\/> is determined by the baseline and the ray defined by point <img loading=\"lazy\" width=\"22\" height=\"33\" align=\"MIDDLE\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img95.png\" alt=\"$ p_1$\"\/>. From above we know that the point <img loading=\"lazy\" width=\"22\" height=\"33\" align=\"MIDDLE\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img96.png\" alt=\"$ p_2$\"\/> lies inside the line <img loading=\"lazy\" width=\"15\" height=\"17\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img8.png\" alt=\"$ l'$\"\/> which is the intersection of plane <img loading=\"lazy\" width=\"19\" height=\"16\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img97.png\" alt=\"$ Pi$\"\/> with the second image plane. In terms of a stereo correspondence algorithm the benefit is that we do not have to search the entire image for the corresponding point <img loading=\"lazy\" width=\"22\" height=\"33\" align=\"MIDDLE\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img96.png\" alt=\"$ p_2$\"\/> but only along the line <img loading=\"lazy\" width=\"15\" height=\"17\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img8.png\" alt=\"$ l'$\"\/>. The fundamental matrix <img loading=\"lazy\" width=\"19\" height=\"16\" align=\"BOTTOM\" border=\"0\" src=\"https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/https:\/\/www.anagram.at\/app\/uploads\/2014\/02\/img89.png\" alt=\"$ F$\"\/> is the algebraic representation of the epipolar geometry and is discussed in the next section. <\/p>\n<\/p>\n<hr\/>\n<p><!--Navigation Panel--><b> Next:<\/b> <a name=\"tex2html317\" href=\"https:\/\/www.anagram.at\/diplomarbeit\/fundamental-matrix\/\">Fundamental Matrix<\/a><br \/>\n<b> Up:<\/b> <a name=\"tex2html313\" href=\"https:\/\/www.anagram.at\/diplomarbeit\/stereo-geometry\/\">Stereo Geometry<\/a><br \/>\n<!--End of Navigation Panel--><\/p>\n<p><\/body><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Epipolar Geometry<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1946,"menu_order":0,"comment_status":"open","ping_status":"open","template":"","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":""},"categories":[],"featured_image_src":null,"featured_image_src_square":null,"_links":{"self":[{"href":"https:\/\/www.anagram.at\/en\/wp-json\/wp\/v2\/pages\/1991"}],"collection":[{"href":"https:\/\/www.anagram.at\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.anagram.at\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.anagram.at\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.anagram.at\/en\/wp-json\/wp\/v2\/comments?post=1991"}],"version-history":[{"count":0,"href":"https:\/\/www.anagram.at\/en\/wp-json\/wp\/v2\/pages\/1991\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/www.anagram.at\/en\/wp-json\/wp\/v2\/pages\/1946"}],"wp:attachment":[{"href":"https:\/\/www.anagram.at\/en\/wp-json\/wp\/v2\/media?parent=1991"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.anagram.at\/en\/wp-json\/wp\/v2\/categories?post=1991"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}