EVEN, Philippe 
  
7 CONCLUSION 
CEA/STR has developed Pyramide, an interactive 3-D modelling system to on-line acquire or update an environment 
model during telerobotics missions. Solid primitives are fit to the visible features of images provided by an on-board 
CCD camera. Time is a key requirement to get a benefit from these techniques. Therefore solutions have already been 
proposed to benefit from the operator’s structural and functional knowledge on the remote environment. 
This modelling principle relies mostly on interactive tasks. The operator manipulates solid primitives in the 3-D space. 
In order to make that task easier, the primitives can be aligned on 3-D directions extracted from image features. Several 
extraction methods are implemented. They rely on the specification of some edge segments, a time consuming and visually 
tiring task when performed in manual mode. 
A semi-automatic edge segment specification mode has been designed and integrated into Pyramide. It relies on an 
automatic function to attract a manually specified edge towards the nearest edge contour. Based on a Hough transform, 
this method is quite robust, and its response time is compatible with the semi-automatic mode requirements. 
The semi-automatic assistance combines manual and automatic tasks. The operator first coarsely draws an initial solution. 
This line segment is immediately attracted towards the better edge in the vicinity. In case of failure due to a spurious edge, 
the operator drags the segment towards the correct edge. Repeated failures are overcome by deactivating the automatic 
function and performing an accurate manual specification. 
This semi-automatic assistance performance have been evaluated on realistic images. It was found to be fast, robust, 
intuitive and flexible. The global modelling time is greatly reduced. Moreover the few failure cases do not entail the 
obtained benefits. 
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