automatique reference of sub figure

[Omar Cheikhrouhou (ISET)]

Hello,

I use the following preambule 

\AtBeginDocument{\renewcommand{\ref}[1]{\mbox{\autoref{#1}}}}

to add the word < Figure > when referencing figure.

However, the word figure is not added when referencing sub-figure. For
example it write 3a instead of Figure 3a.

Please, what to add in order to get the word Figure before number of fig

Thanks in advance,