Unfortunately, this gadget has been used mainly for personal purposes such as entertain- ment (e.g., recording picnic without worrying of carrying cameras by hands) or even criminal actions (e.g., secretly recording in private or prohibited areas), not much for public security. Recently, there is an interesting application used for US police force as an on-officer cameras. This system aims to ”catch you in the act, right to remain silent imperative”, as announced in 2.