1. A method of operating a surveillance system having a display unit configured to display a surveillance image of a surveillance location, the method comprising: acquiring the surveillance image of the surveillance location; receiving a first text input by a user; analyzing the received first text and the acquired surveillance image; extracting, by at least one processor, a part of the acquired surveillance image corresponding to a part of the surveillance location, wherein the part of the surveillance location corresponds to a meaning of the received first text that is obtained based on a result of analyzing the received first text; setting the part of the surveillance image as a surveillance region; displaying a surveillance object corresponding to the received first text such that the surveillance object is overlapped with the surveillance region; receiving a second text input by the user, the second text input corresponding to the displayed surveillance object; displaying the surveillance object together with the received second text; setting a surveillance event that occurs with respect to the surveillance object based on at least one of the meaning of the received first text or a meaning of the second text that is obtained based on a result of analyzing the received second text; analyzing, by at least one processor, the surveillance region corresponding to the surveillance object and determining whether the set surveillance event has occurred based on a result of analyzing the surveillance region; and responsive to a determination that the set surveillance event has occurred, performing an indicating operation in the surveillance system.