US Patent 7131132 Automatic access denial

A method for limiting access to a device to a particular authorized user. The method includes; obtaining visual data related to the appearance of a user of the device; processing the visual data to determine when the particular authorized user is present; allowing initial access to the device when the particular authorized user is present; allowing continued access to the device when the particular authorized user is present; and terminating access to the device when the particular authorized user is not present.