1. A method to build a 3-dimensional grid map, comprising: acquiring a peripheral omni-directional image using a stereo omni-directional camera; confirming a current 2-dimensional location using the omni-directional image; performing 3-dimensional restoration of the omni-directional image; and building the 3-dimensional grid map of the periphery of the stereo omni-directional camera by combining a result of the 2-dimensional localization and a result of the 3-dimensional restoration.