Pose-Space Image-based Rendering
One principal intention of computer graphics is the achievement of photorealism. Although modeling, animation and simulation tools for rendering of complex objects (e.g. human bodies, faces, or clothes) have been developed in the past decades, achieving real photorealism by physically simulating material properties and illumination is still computationally demanding and extremely difficult. Instead of relying on physical simulation, we follow a different approach for photo-realistic animation of complex objects, which we call Pose-Space Image-Based Rendering (PS-IBR). Our approach uses images as appearance examples to guide complex animation processes, thereby combining the photorealism of images with the ability to animate or modify an object. The main idea of PS-IBR is to define a suitable space (the pose-space) that captures characteristic appearance dependencies of the object, and is used as domain to interpolate and merge images of the object in different configurations. For articulated objects, such a space can be e.g. parameterized by a skeletal pose representation.
For articulated objects, we assume that appearance depends on the configuration of bones and joints, such that the pose-space is spanned by a skeletal representation of pose.
Spatio-intensity image warps on top of a low-resolution purely geometric animation implicitly extract pose-dependent appearance and shading from the images. The images and warps are parameterized in pose- space, i.e. the space of body poses, and interpolated using scattered data interpolation to synthesize images for new pose configurations. This allows a photorealistic animation and rendering without the need to physically simulate the underlying scene and object properties.
Visualization of geometric and photometric image warps extracting characteristic appearance changes on a face during expression changes.
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A. Hilsmann
Image-based Approaches for Photo-Realistic Rendering of Complex Objects, Dissertation , , Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, March 2014.
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A. Hilsmann, P. Fechteler and P. Eisert:
Pose Space Image Based Rendering, Computer Graphics Forum 32(2) (Proc. of Eurographics 2013), pp. 265-274, May 2013.
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A. Hilsmann and P. Eisert:
Image-based Animation of Clothes, Eurographics 2012 Short Paper, Cagliari, Italy, May 2012.
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