A first light detector and a second light detector, in each of which a plurality of light-receiving elements are arranged in an adjoining manner, are respectively provided anterior to an image-forming point of first reflected light and posterior to an image-forming point of second reflected light. The method includes obtaining, by the terminal, at least one BCAST service from a visiting network when the terminal roams in the visiting network. The lateral edges of the panels are cut off so that the panels are no longer interconnected. The outer tube and inner structure are located so as to define at least one auxiliary lumen.