Fast Shading and Shadowing of Virtual Objects Using Shadowing Planes in Mixed Reality

We have developed a fast shading and shadowing method that uses the shadowing planes and the basis images in mixed reality (MR). The method is model-based and computable in real time by using a standard graphics processing unit (GPU) making it particularly effective when used with an outdoor MR application. To express the shadows of objects, we map the shadow images that are synthesized from the basis images rendered offline with the basis lights onto the shadowing planes, and we compute alpha blending with the objects. The shadowing planes are generated from convex hulls of objects. We obtain the radiance parameters of the real scene from an omnidirectional image and compute the linear sum of the radiance parameters and the basis images on the GPU. We applied this shadowing method to both an indoor and outdoor MR application and found it to be effective.

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