A brewing apparatus, in particular for brewed beverage vending machines, the brewing apparatus having a fixed axis; a fixed frame; a reversible drive; and a number of movable driven members all connected directly or indirectly to the drive to only oscillate about the fixed axis andor move radially with respect to the fixed axis. The head protection device further includes an inflator for spouting gas into the pipe along a side rail of a vehicle body. The carbon dioxide gas releasing solid material releases carbon dioxide when heated by the heating element. This method includes: a first step of merging the initial tracks which correspond substantially to identical observation directions ; and a second step of frequency analysis of the tracks resulting from merging the initial tracks and of characterizing the merged tracks whose spectrum takes the form of a harmonic comb characteristic of a single real object.