Knyaz, Vladimir 
  
4 TEXTURE MAPPING 
The original method is developed for the photorealistic texture generation and accurate mapping. The method deals with 
uniform 3D model obtained by above technique and presented in triangulation form. For texture generating it is 
converted into regular mesh model presentation, which allows using a set of object digital images from different view 
points for uniform photorealistic texture creation. Regular mesh is obtained by following procedure. For every point 
(x pXpj ) its Cartesian coordinates transform into spherical or cylinder coordinate system. Then the number of 
mesh bundles is determined providing accurate model geometry presentation. For each bundle its height in new 
coordinate system is computed by finding the triangle including given points and linear interpolating between the 
triangle tops. 
The next problem to be solved is to perform model mesh segmentation into fragments providing the best texture 
generation from given set of images. For creating accurate orthophoto to select model fragment so that image 
transformation caused by object curvature would be lowest. To find model mesh segmentation satisfying this condition 
the map of normal to the model surface is computed and for each image the model fragment is determined providing 
two conditions: minimum fragment curvature for given image and closed model generation. 
For achieving accurate uniform texture the orthophoto for the object's fragments is created using appropriate image and 
fragment model as regular mesh. Then texture fragments are integrated in united texture model. 
The method is developed for two variants of object images available: (a) image exterior orientation is known or can be 
determined and (b) image exterior orientation is unknown. 
If image exterior orientation is known the texture for each fragment is generated by well-known image 
orthotransformation procedure including the following steps: 
mesh discrete and texture scales computation; 
image coordinate for mesh bundles computation; 
image linear transformation parameter determination 
image transformation 
If image exterior orientation is unknown the parameters of exterior orientation is found using 3D model and original 
software. To determine exterior orientation parameters operator marked the corresponding reference points on 3D 
model and in the image (Knyaz, 1998). This allows to find image EO parameter by technique based on reference points. 
In Fig. 5(a) the object of traditional Russian folk art "Dymkovskaya igrushka" to be reconstructed is presented. The 
results of uniform surface generation using spherical projection are shown in Fig. 5(b). 
       
   
   
    
    
     
    
   
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Figure 5: Results of reconstruction 
Then the described procedure of uniform texture orthphoto has been performed resulting in image shown in Fig. 5(a). 
For texture generation 8 images of object has been used. The image exterior orientation has been known due to special 
  
432 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B5. Amsterdam 2000.