Full parallax computer generated hologram using GPU-accelerated ray tracing method

Abstract

In Computer Generated Hologram (CGH), the hidden surface removal is needed to display 3D objects. Some methods of the hidden surface removal for a CGH have been proposed. However, these methods are unsuitable to make realistic images that have the complicated reflection, refraction and shadowing. We propose a calculation method of CGH using the ray tracing method. In the ray tracing method, complicated descriptions are expressed with a simple algorithm. The ray tracing method is avoided ever in CGH having a very high resolution because of enormous calculation cost. In order to speed up, we attained improvement of the calculation time using a graphics processing unit (GPU). The ray tracing from one viewpoint is unable to express full parallax CGHs. In this study, a hologram plane is divided into elementary holograms, and the center of each elementary hologram is made the starting point of the ray. Then, sets of point light every elementary hologram are constructed by the ray tracing method. As a result of optical reconstruction, it was confirmed that hidden surface removal was conducted when plural objects were in one scene. Moreover the texture of material and shadows by a front object were expressed.