1. An information processing apparatus comprising: a background image storage unit configured to store a background image; a periodic event storage unit configured to store conditions for the occurrence of a periodic event and information as to the time of the occurrence of the periodic event; an image input unit configured to input an image; an image comparison unit configured to compare the background image stored in the background image storage unit with an input image input from the image input unit to obtain a difference; a determination unit configured to determine, after change in the difference and time of the occurrence of the change is detected with us of the comparison by the image comparison unit, whether a predetermined time has elapsed or not; a periodic event collation unit configured to collate a change in the difference and time of the change with the conditions for the occurrence of the periodic event and the information as to the time of the occurrence of the periodic event stored in the periodic event storage unit in order to determine whether the change of the input image in state is the periodic or the non-periodic movement of an object when it is determined that the predetermined time has elapsed by the determination unit; and a selection unit configured to select, according to the result of a determination by the periodic event collation unit, any one of operations according to the periodic or the non-periodic movement of an object, and wherein even when the periodic event collation unit determines that the change in state is the non-periodic movement of an object and when the movement of an object is repeated the predetermined number of times or more, the conditions and the information stored in the periodic event storage unit are changed so that the periodic event collation unit can determine that the movement of the object is the periodic movement of the object.