An algorithm is presented for identifying the visual events of solids of revolution from a perspective point of view. The object representation model comprises of these different visual events (or aspects) which can be applied for object identification. Algorithms have been developed to handle general polyhedral objects from either orthographic or perspective views, or to compute the aspect graph of solids of revolution using the orthographic projection. The orthographic view aims to find the aspects of the solid of revolution which are purely object-oriented, the theory of differential geometry can be applied sufficiently to find the aspects without referring to the distance of the viewer. In the real case, the distance effect, that may influence the aspect dramatically when the viewer is close to the object, has to be considered. For instance, to generate the same aspect, the viewer may have to change his viewing directions when he is at a different distance from the object. Firstly, this paper uses the constraint of contour generator to identify the aspects of solids of revolution under perspective projection. The difference between our approach and the others is the distance effect. The present method combines the object-oriented and viewer-oriented aspect finding. Secondly, a method is developed to find the limb termination point of the non-transparent object from a certain perspective viewpoint. Many aspect finding methods are developed for transparent objects (i.e. objects made of glass) of which the projection contour (limb) is continuous. For non-transparent objects, the self-occlusion may induce the limb termination phenomena.
