3 corresponds to the plate characters 2 7 z see fig4 a the pm alphabet symbol u03b8 8 corresponds to the plate characters 8 b e f see fig4 a the pm alphabet u03b8 13 corresponds the plate characters k v y x see fig4 a and so on the new alphabet created on the base of empirical observations summarizes and synthesizes the alphanumeric characters of the plate as previously said and as also recognized by the ep1276086 the main problem in the process of plate recognition is the noise present in real world images the source of this noise can be due to illumination changes dust on the plates rain sudden movements noise of the camera acquisition means and so on experimental results have shown that this noise causes miss classification of the original symbols for example o letter o 0 zero d and q can be easily miss classified among them another case of ambiguity is represented by the b letter and the number 8 see fig7 this miss classification due to unavoidable noise presence obviously renders a plate recognition system not reliable the solution to this problem and the central essence of this invention is that it is not important to correctly identify the elements of the plate but to correctly categorize them therefore the elements o 0 d q are grouped together in the same category the pm alphabet element u03b8 1 in fact for what the application is concerned it is.