1. Field of the Invention
The present invention relates to computer graphics technology, and more particularly, to technology for generating three-dimensional model information for a physical object to be used in rendering a three-dimensional object.
2. Description of the Related Art
Computer graphics (CG) technology is widely used in a variety of fields. In recent years in particular, with advances in three-dimensional CG technology, application to solid object simulation is common.
As an example application of three-dimensional CG technology, mixed reality systems are known. A mixed reality system is a system that represents a virtual object as seen from the viewpoint of an observer in CG and registers and superimposes it on an actual image sensed from the vicinity of the viewpoint of the observer. By observing a superimposed image of the CG and the actual image according to the viewpoint position of the observer, the observer is able to experience a mixed reality in which there appears to be a virtual object in physical space. Compared to a conventional virtual reality system (VR system), a mixed reality system makes possible more realistic observation, with a sense of actual scale.
Using mixed reality systems, attempts have been made to carry out various types of inspections, such as usability, maintainability, and assemblability, of objects designed using three-dimensional CAD. For example, methods have been proposed in which, by representing a prototype as a three-dimensional virtual object using CG and displaying it according to motions of a hand, which is a physical object, manipulation and inspection are carried out with one's own hand as if the prototype were there. In this case, the hand of the operator must also be represented as a three-dimensional virtual object by CG and display in accordance with actual hand and finger motions must be carried out.
When manipulating another virtual object (such as the prototype described above) with a hand (virtual hand) represented by CG, it is necessary to carry out a determination of contact between the virtual hand and the other virtual object. At this time, if the shape of the virtual hand is too real, the determination process becomes complicated. As a result, the virtual hand is often represented by a simplified-shape model without detailed information such as the fingernails and the like and the contact determination carried out.
However, because a virtual hand reflects the motion and the position and orientation of the physical (real) hand, if the shape of the virtual hand differs too greatly from the shape of the real hand the operator experiences a sense of incongruence.
In order to display a virtual hand that matches motions of the real hand it is necessary to detect the state of the real hand, specifically by using methods like the following:
(1) A method that mounts on the real hand sensors that detect amounts of deformation and measures the state of the hand (Japanese Patent Laid-Open No. 10-176919)
(2) A method that senses a real hand and deduces the shape of the three-dimensional hand from the image of the two-dimensional hand.
With method (1), attaching the sensors is difficult and time-consuming, and where the detected deformation amount is not accurate a discrepancy arises between the shape of the virtual hand and that of the real hand. In addition, with method (2), the calculating load to compute the shape of the three-dimensional hand from the image of the two-dimensional hand is very great, and given current computational device capabilities it is not possible to apply this method to mixed reality systems, which require computation in real-time.