1. A method for localizing a mobile robot using arbitrarily shaped (AS) ceiling features, comprising: a device providing step of providing a mobile robot device which is localized using the arbitrarily shaped ceiling features and includes an image input unit, an encoder sensing unit, an arithmetic unit, a control unit, a storage unit, and a driving unit; a feature extraction step of extracting features which include an arbitrarily shaped feature from a contour extracted from image information inputted through the image input unit; and a localization step of localizing the mobile robot device using the extracted features, wherein a descriptor indicating the characteristics of the arbitrarily shaped feature is assigned in the feature extraction step.