EG2016

Permanent URI for this community

https://diglib.eg.org/handle/10.2312/15062

Browse

Browsing EG2016 by Subject "Applications"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    A 3D Morphable Model of the Eye Region
    (The Eurographics Association, 2016) Wood, Erroll; Baltrušaitis, Tadas; Morency, Louis-Philippe; Robinson, Peter; Bulling, Andreas; Luis Gonzaga Magalhaes and Rafal Mantiuk
    We present the first 3D morphable model that includes the eyes, enabling gaze estimation and gaze re-targetting from a single image. Morphable face models are a powerful tool and are used for a range of tasks including avatar animation and facial expression transfer. However, previous work has avoided the eyes, even though they play an important role in human communication. We built a new morphable model of the facial eye-region from high-quality head scan data, and combined this with a parametric eyeball model constructed from anatomical measurements and iris photos. We fit our models to an input RGB image, solving for shape, texture, pose, and scene illumination simultaneously. This provides us with an estimate of where a person is looking in a 3D scene without per-user calibration - a still unsolved problem in computer vision. It also allows us to re-render a person's eyes with different parameters, thus redirecting their perceived attention.
  • Thumbnail Image
    Item
    Generalized As-Similar-As-Possible Warping with Applications in Digital Photography
    (The Eurographics Association and John Wiley & Sons Ltd., 2016) Chen, Renjie; Gotsman, Craig; Joaquim Jorge and Ming Lin
    Discrete conformal mappings of planar triangle meshes, also known as the As-Similar-As-Possible (ASAP) mapping, involve the minimization of a quadratic energy function, thus are very easy to generate and are popular in image warping scenarios. We generalize this classical mapping to the case of quad meshes, taking into account the mapping of the interior of the quad, and analyze in detail the most common case - the unit grid mesh. We show that the generalization, when combined with barycentric coordinate mappings between the source and target polygons, spawns an entire family of new mappings governed by quadratic energy functions, which allow to control quite precisely various effects of the mapping. This approach is quite general and applies also to arbitrary planar polygon meshes. As an application of generalized ASAP mappings of the unit grid mesh, we demonstrate how they can be used to warp digital photographs to achieve a variety of effects. One such effect is modifying the perspective of the camera that took a given photograph (without moving the camera). A related, but more challenging, effect is re-photography - warping a contemporary photograph in order to reproduce the camera view present in a vintage photograph of the same scene - taken many years before with a different camera from a different viewpoint. We apply the generalized ASAP mapping to these images, discretized to a unit grid. Using a quad mesh (as opposed to a triangle mesh) permits biasing towards affine maps of the unit squares. This allows the introduction of an As-Affine-As-Possible (AAAP) mapping for a good approximation of the homographies present in these warps, achieving quite accurate results. We demonstrate the advantages of the AAAP mapping on a variety of synthetic and real-world examples.
  • Thumbnail Image
    Item
    A Generic Physically-based Approach to the Opening Design Problem
    (The Eurographics Association, 2016) Κalampokis, Konstantinos; Papaioannou, Georgios; Gkaravelis, Anastasios; T. Bashford-Rogers and L. P. Santos
    Today architectural design harnesses photorealistic rendering to accurately assess energy transport for the design of energyefficient buildings. In this context, we present an automatic physically-based solution to the opening design problem, i.e. the goal-driven process of defining openings on the input geometry given a set of lighting constraints, to better exploit natural daylight. Based on a hierarchical approach that combines a linear optimization strategy and a genetic algorithm, our method computes the optimal number, position, size and shape of openings, using a path tracing-based estimator to precisely model the light transport for arbitrary materials and geometry. The method quickly converges to an opening configuration that optimally approximates the desired illumination, with no special geometry editing requirements and the ability to trade quality for performance for interactive applications. We validate our results against ground truth experiments for various scenes and time-of-day intervals.
  • Thumbnail Image
    Item
    Interactive Deformation of Structurally Complex Heart Models Constructed from Medical Images
    (The Eurographics Association, 2016) Nakashima, Kazutaka; Koyama, Yuki; Igarashi, Takeo; Ijiri, Takashi; Inada, Shin; Nakazawa, Kazuo; T. Bashford-Rogers and L. P. Santos
    We present a data structure for interactive deformation of complicated organ models, such as hearts, and a technique for automatically constructing the data structure from given medical images. The data structure is a dual model comprising of a graph structure for elastic simulation and a surface mesh for visualization. The system maps the simulation results to the mesh using a skinning technique. First, the system generates a dense graph and mesh from input medical images; then, it independently reduces them. Finally, the system establishes correspondence between the reduced graph and mesh by backtracking the reduction process. We also present an interactive browser for exploring heart shapes, and report initial feedback from target users.