1. A simultaneous localization and map building method of a mobile robot including an omni-directional camera, comprising: acquiring an omni-directional image from the omni-directional camera; dividing the acquired omni-directional image according to a preset reference to generate a lower image and an upper image; extracting feature points from the lower image and calculating visual odometry information to track locations of the extracted feature points based on a location of the omni-directional camera; and performing localization and map building of the mobile robot using the calculated visual odometry information and the upper image as an input of an extended Kalman filter.