3d computer model processing apparatus

Abstract

In a computer processing apparatusa 3D computer model comprising a polygon meshrepresenting the visual hull of an objectis generated by processing images of the object recorded at different positions and orientations to back-project the silhouette of the object in each image to give a respective cone which constrains the volume of 3D space occupied by the object. To remove concave and convex artefactsin the polygon meshthe polygon mesh is projected into each image to give a respective reference silhouette for each image. A change is made to at least one edge or vertex in the polygon mesh to give a refined polygon mesh, which is then projected into each image. The resulting silhouette in each image is tested against the corresponding reference silhouette. If the silhouette of the refined polygon mesh is the same as each reference silhouette, to within an allowable tolerance, then the changed edge or vertex is allowed in the polygon mesh, otherwise the polygon mesh is returned to its previous state. This processing to change and test the polygon mesh is carried out a number of times. Artefacts are removed from the polygon mesh because their removal does not make the polygon mesh inconsistent with the reference silhouettes. Parts of the polygon mesh representing actual features of the object are not changed because such a change causes the polygon mesh to become inconsistent with at least one reference silhouette and therefore such a change is rejected.