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Item Restoration of Color in Noh Masks Based on Retinex Algorithm(The Eurographics Association, 2006) Yin, Xin; Miichi, Yasuo; Tanaka, Hiromi T.; Marinos Ioannides and David Arnold and Franco Niccolucci and Katerina ManiaNoh is a famous traditional Japanese dramatic art. The restoration of ancient Noh masks is an important aspect of the preservation of cultural heritage. In this paper, we developed a technique based on Retinex algorithm and it can be applied to restore the color of 3D objects such as the Noh mask. The Retinex algorithm simulates the ability of human eye and can adjust the color of the 2D image. To apply the Retinex algorithm on the 3D surface, the shape of the object is taken into account. The original color of the target points can be got by reference to the color of the surrounding points sampled according to a uniform route. The effectiveness of this technique is demonstrated by the implementation results. This technique can be used to infer the color of other 3D objects also.Item Reconstruction of Volumetric Surface Textures for Real-Time Rendering(The Eurographics Association, 2006) Magda, Sebastian; Kriegman, David; Tomas Akenine-Moeller and Wolfgang HeidrichVolumetric texturing is a popular technique for rendering rich 3-D detail when a polygonal surface representation would be ineffective. Although efficient algorithms for rendering volumetric textures have been known for years, capturing the richness of a real-life volumetric materials remains a challenging problem. In this paper we propose a technique for generating a volumetric representation of a complex 3-D texture with unknown reflectance and structure. From acquired reflectance data in the form of a 6-D Bidirectional Texture Function (BTF), the proposed algorithm creates an efficient volumetric representation in the form of a stack of semi-transparent layers each representing a slice through the texture s volume. In addition to negligible storage requirements, this representation is ideally suited for hardware-accelerated real-time rendering.Item A Spectral BSSRDF for Shading Human Skin(The Eurographics Association, 2006) Donner, Craig; Jensen, Henrik Wann; Tomas Akenine-Moeller and Wolfgang HeidrichWe present a novel spectral shading model for human skin. Our model accounts for both subsurface and surface scattering, and uses only four parameters to simulate the interaction of light with human skin. The four parameters control the amount of oil, melanin and hemoglobin in the skin, which makes it possible to match specific skin types. Using these parameters we generate custom wavelength dependent diffusion profiles for a two-layer skin model that account for subsurface scattering within the skin. These diffusion profiles are computed using convolved diffusion multipoles, enabling an accurate and rapid simulation of the subsurface scattering of light within skin. We combine the subsurface scattering simulation with a Torrance-Sparrow BRDF model to simulate the interaction of light with an oily layer at the surface of the skin. Our results demonstrate that this four parameter model makes it possible to simulate the range of natural appearance of human skin including African, Asian, and Caucasian skin types.Item Artist-Directable Real-Time Rain Rendering in City Environments(The Eurographics Association, 2006) Tatarchuk, Natalya; Isidoro, John; Norishige Chiba and Eric GalinPhotorealistic rain greatly enhances the scenes of outdoor reality, with applications including computer games and motion pictures. Rain is a complex atmospheric natural phenomenon. It consists of numerous interacting visual effects. We present a comprehensive real-time system for the realistic rendering of rain effects in complex environments in real-time. Our system is intuitive, flexible and provides a high degree of artistic control for achieving the desired look. We describe a number of novel GPU-based algorithms for rendering the individual components of rain effects, such as a hybrid system of an image-space approach for rainfall and the particle-based effects for dripping raindrops and splashes; water surface simulation for ripples; animation and rendering of water droplets trickling down on transparent glass panes; view-dependent warped reflections and a number of additional effects. All our techniques respond dynamically and correctly to the environment lighting and viewpoint changes as well as the atmospheric illumination due to lightning. Our effects can be rendered at interactive rates on consumer graphics hardware and can be easily integrated into existing game and interactive application pipelines or offline rendering.