1. A robot cleaner, comprising: a detection unit to detect structures within a cleaning region; a storage unit to store information regarding the detected structures; and a control unit to compare information regarding the structures detected by the detection unit after a stopped cleaning operation is restarted with structure information stored in the storage unit before the cleaning operation was stopped, and to initiate a cleaning operation with respect to the cleaning region by recognizing an absolute position of the robot cleaner based on the comparison.