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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004 
  
4. CONCLUSION 
The mathematical model for the SFS is established based on 
the fact that the pixel's gray level variations in image space are 
proportional to the shading intensity variations of the terrain 
morphology. The terrain shades in its turn is the function of the 
illumination intensity and the direction of the incident light 
with respect to the local surface orientation as well as the 
incident light direction and the terrain albedo. In this project the 
Lambertian model is utilized for modeling the terrain 
reflectivity property. 
The result for the real image shows that the lambertian 
reflection does not sufficiently describe surface reflectance 
properties. Surfaces with unknown and varying albedo must be 
considered. 
There are several possible directions for future research. As we 
noted, reflectance models used in SFS methods are too 
simplistic; recently, more sophisticated models have been 
proposed. This not only includes more accurate models for 
Lambertian, specular, and hybrid reflectance, but also includes 
replacing the assumption of orthographic projection with 
perspective projection, which is a more realistic model of 
cameras in the real world. 
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