

In this research work, a complete quality study of our 
scheme~\cite{fgb11:ip} has been given, namely robustness, 
completness, and correctness.
This scheme is now ready for practical
use.

To improve again the robustness, notice that the definition of $x$ 
can be changed as follows: at worst, any process wich always returns 
the same set of  bits for a given image would return an amanable vector.
However, the most fine would be the set of bits whose modifications minimize
a distortion function. Following such idea we plan to combine this bit 
selection step with feature extraction function.

