A method for controlling a mobile terminal, and which includes receiving, via an input unit, a selection signal indicating a selection of a predetermined button among multiple predetermined buttons on the mobile terminal, in which the multiple predetermined buttons corresponding to different preset functions executed on the mobile terminal; capturing, via a camera included on the mobile terminal, a preview image of an object upon receiving the selection signal; recognizing, via a controller included on the mobile terminal, a character string included in the captured preview image; and performing, via the controller, a preset function using the recognized character string and that corresponds to the selection of the predetermined button.