Integration to the 
|. 3D Mode 
    
  
in and treatment) 
OMPUTER VISION 
| view with a large angle. 
in painting, drawing and 
of panoramas and several 
sui, 2012), (Hugin, 2012) 
es of panoramas, the data 
are created, manually or 
sive several examples of 
d explain a few basics to 
ware. 
ction depends on the way 
n the software used, or on 
yecific application, the use 
stance, it is possible to use 
nerated thanks to six cube 
ons: the stereographic one, 
round in the middle of the 
' them, extracted from the 
d the most cited in the 
;o main spherical formats: 
able to display the whole 
» the horizon, 90° up and 
needed to view spherical 
do it. 
y used by à couple of 
PTViewer and SPi-V. It 
ct ratio of 2:1 (that is, the 
. 
be faces to fill the whole 
c is remapped to the cube 
faces which fit seamlessly. One very wide spread cubic format is 
QuickTime VR. It consists in one file containing the 6 faces as 
JPEG compressed images together with a header giving basic 
information how the panorama should be displayed. 
Another cubic format is used by SPi-V. It consists in the 6 cube 
faces in a single row or column. SPi-V treats any image with an 
aspect ratio of exactly 6:1 as a cubic spherical panorama. 
This format is the one we finally used to create panoramas from 
the 3D model thanks to 6 exports. This part will be described 
later in this paper. 
  
  
  
  
  
Figure 2. Cubic format: panorama made of 6 square pictures 
There are a number of possibilities to display partial panoramas - 
these are panoramas that don't fill the whole sphere in one or the 
other way. Partial panoramas can be displayed directly if they 
don't cover more than approximately 120° along the shorter side 
(that is they can be 360° in one direction but must be 120° or 
less in the other direction). The main formats are Cylindrical and 
Rectilinear, but partial spherical panoramas are possible too. 
Cylindrical panoramas can show a full circle along the horizon 
ora part of it. They are very popular for landscape panoramas. If 
they are used for architectural subjects it might be of bother that 
horizontal lines, except the horizon itself are bent. 
Rectilinear panoramas display the subject just like an ordinary 
(non-fisheye) lens would do. The horizontal and vertical field of 
view are limited to about 120°. Straight lines stay straight; hence 
they are good for architectural subjects. But if either field of view 
is too large they suffer from unnatural looking distortions in the 
corners. 
4 MATERIALS AND METHODS: CREATION OF THE 
VIRTUAL TOUR 
41 Panorama creation 
Kolor AutoPano Giga , PTGui and Hugin. PTGui and Hugin are 
really closed to each other to assemble a mosaic of photographs 
mo a complete immersive panorama or to stitch any series of 
overlapping pictures. Before using a corner detector, the images 
have to be acquired. Those images must have a sufficient 
recovery to allow the software to find tic points. It has to cover 
the whole view. 
After that, there are settings to pay attention to: 
* Quality of detection 
Number of tic points 
Type of point of view (single or multiple) 
Corrections 
Type of algorithm 
     
   
    
     
    
   
   
   
  
  
  
  
  
  
  
  
   
  
    
  
    
   
    
   
    
    
     
    
    
    
   
     
    
   
  
      
  
      
   
    
  
   
     
  
    
  
* Projection 
It is possible to create a panorama of a virtual model in the same 
way as with real pictures. In this case, there are still a few 
problems remaining, but we can assume that it would be easier 
with the real model which would present more characteristic 
points. However, there are many steps to create one single 
perfect panorama (detailed in the following scheme, Figure 3). 
The issue at stake here is to find a more efficient way to create 
panoramas from the 3D model in order to be able to recreate 
them easily if necessary. One option was to export the model to 
3DS format. This software proposes an application dedicated to 
the creation of panorama from a 3D model from a given point of 
view, with parameters you enter. Because of the size of the model 
the export was still difficult. By size, we mean complexity, which 
implied a huge time to export the data even with a professional 
device. One single change on the 3D model would have implied 
another export of the model which was also not efficient enough. 
The next part will deal with a second option using a Google 
Sketchup plug-in called CubicPanoOUT which will give a 
solution to this problem of efficiency. 
4.2 CubicPanoOUT: creation of panorama from 3D model 
After researches we figured out that there were no way and no 
plug-in to create panoramas directly from Google Sketchup. 
However, there is a script proposed by J. Wehby which was 
supposed to export JPG cube images for the creation of 
panoramas. This plug-in you can use after copying it into 
Sketchup roots file will allow you to export six square images 
from a given point of view. Those pictures have no “common 
area”. It is then not possible to build panoramas thanks to corner 
detector as we described before because no tie points are 
available. However, it is possible to apply a mathematical 
transformation to the six pictures to create a cubic panorama. 
The following six pictures we extracted from the test model 
thanks to CubicPanoOUT (Figure 2). The Figure 3 sums up the 
two ways to extract panoramas from a 3D virtual model. 
3D Model 3D Model 
    
Positioning, Height, Shadows : : 
Positioning, Height, Shadows 
     
ue 
  
EXPORT of several images with ; 
common areas Cubic Pano Out 
Exportation of 6 pictures 
{cube Faces} 
Importation into AutoPano or 
Ptgui 
  
  
importation into Panotour Pro 
corner detector: automatic 
detection of tie points 
  
  
Creation of the panorma 
; S Spheric Projection 
Creation of a first panorama : i 
      
ue 
; ; integration to the tour 
corrections if necessary 
integration to the tour 
Figure 3a. Figure 3b. 
Classic method for panorama Panorama creation from 3D 
creation from 3D model model with CubicPanoOUT