1. A method of composing a plurality of three-dimensional data obtained by measuring an object from a number of viewpoints, said plurality of three-dimensional data defining a plurality of original meshes representing a plurality of surface images of said object observed from different directions and/or distances, said method comprising the steps of: (a) converting said plurality of original meshes into a first surface mesh through a volumetric method; and (b) correcting a mesh structure of said first surface mesh by comparing said first surface mesh with said plurality of original meshes, to thereby obtain a second surface mesh; and (c) correcting a local position of said second surface mesh by comparing said second surface mesh with said plurality of original meshes, to thereby obtain a third surface mesh, wherein each mesh is defined by a set of polygons, and a composed result of said plurality of three-dimensional data is given by data representing said third surface mesh.