1. An image processing system adapted to recognize an object disposed on a predetermined world surface, the system comprising: means for calibrating a visual environment by defining a world coordinate system relative to a world surface and determining a transformation between coordinates in an image coordinate system and coordinates in said world coordinate system, in order to define the predetermined world surface; means for acquiring an image of the object disposed on the predetermined world surface in a calibrated visual environment, the image comprising a distorted projection of the world surface; means for analyzing the acquired image to locate one or more local features of the image, with respect to the image coordinate system of the image; means for mapping the local features into said world coordinate system of the world surface according to said transformation; and means for matching the mapped local features to a model defined in the world coordinate system.