====== Input Data  ======

<fc #ff0000>Important:</fc> The informations on this page will probably be subject of change. This will be communicated during labs sessions.

===== Images of the Scene =====

The goal of the work during the whole term is to reconstruct a 3D object (scene) from its images. In order to make the task manageable, we have chosen such a scene, that is relatively uncomplicated considering 3D computer vision methods: a decorative portal. The simplicity of such a scene lies in the fact, that the scene is almost planar and small number of views is enough for reconstruction.

We have prepared data captured at several places, see [[http://cmp.felk.cvut.cz/cmp/courses/TDV/data|Data]]. The capturing scheme consists of three levels of height, four pictures in each. The capturing scheme is in <imgref fig_scheme>. All images are captured with the same zoom setting, i.e. the same internal camera calibration matrix **K**. The matrix is provided in each data set.

|<imgcaption fig_scheme|Capturing scheme>{{:courses:tdv:labs:portal_capture.png|}}</imgcaption>|<imgcaption fig_images|Example input images>{{:courses:tdv:labs:images_captured_all.png|}}</imgcaption>|

Since the 3D reconstruction algorithms use the (linear) perspective camera model, the radial distortion of input images has been removed.

===== Sparse Correspondences =====

The sparse correspondences for provided scenes has been computed and they are available. Note, that the correspondences are tentative, so they contain also mismatches.

The correspondences are stored in several files:

  * coordinates of detected points are stored in the files ''u_<id>.txt'', one row per coordinate pair ''x y'', where ''<id>'' is the image identifier (two digit number)

  * 0-based indices of corresponding points are stored in the files ''m_<i1>_<i2>.txt'', one row per pair of indices, where ''<i1>'' and ''<i2>'' are identifiers of two images, ''i1'' < ''i2''

Example:

The file ''m_05_06.txt'' begins with,
   4 7
   5 18285
  11 27631
  ...
    
the file ''u_05.txt'' begins with
   5.3 1613.4
   7.0  364.8
   9.5 1522.3
   9.9  585.1
  10.9  571.7  <---
  11.2  578.6
  11.3  666.1
  ...

and the file ''u_06.txt'' begins with
   6.3 1749.0
   8.4 1753.3
   8.9  497.9
  10.4  540.9
  11.0  683.2
  11.0  687.8
  11.1  589.8
  11.3  583.4  <---
  12.1 1212.6
  12.2  949.3
  ...
   
The first row in ''m_05_06.txt'' means, that the point 4 from the image ''05'' and the point 7 from the image ''06'' corresponds. I.e., the point with coordinates ''x=10.9, y=571.7'' in the image ''05'' corresponds to the point ''x=11.3, y=583.4'' in the image ''06''.