1. A mobile terminal comprising: a display; a user input unit configured to receive inputs; a memory configured to store information; a camera configured to capture images; a controller configured to: cause the display to display a preview image received via the camera, wherein the preview image includes a specific object; determine a real size of the specific object with reference to a preset standard object having an assigned standard size according to a type of the standard object from a plurality of types of the standard object each having a different assigned standard size; determine an actual distance from the mobile terminal to the specific object based on the displayed preview image and the assigned standard size of the type of the standard object; cause the display to display information of the actual distance; cause the display to display a list comprising information of a plurality of related objects located within a predetermined distance from the specific object which is located within the actual distance from the mobile terminal in response to a first selection input to the specific object received via the user input unit; set metadata information of a selected one of the plurality of related objects to metadata information of the specific object in response to a second selection input to the selected one of the plurality of related objects received via the user input unit; acquire current position information of the mobile terminal and direction information of the specific object relative to the mobile terminal; acquire position information of the specific object using the acquired current position information, the actual distance of the specific object from the mobile terminal, and the acquired direction information, wherein the direction information is acquired based on a direction faced by the mobile terminal; set the acquired position information of the specific object to the metadata information for the specific object; cause the memory to store the metadata information of the specific object; search the memory for the stored metadata information of the specific object; and cause the display to display information of the selected one of the plurality of related objects.