Image processing, virtual anatomy-editing tools, and computational solvers (CFD) offer unique opportunities for pre-operatively modeling and evaluating surgical repairs of congenital heart disease, such as single ventricle defects. In a recent case, three patient-specific Fontan models were evaluated using CFD. To better understand their impact on entire circulation, we extend this work by performing lumped parameter simulations with a circuit analog of the cardiovascular system. For the relatively small range of resting Fontan resistances evaluated (0.66–1.30 WU), large decreases in cardiac output (12%) and systemic arterial pressure (9%), and a slight increase in mean systemic venous pressure (2%) were observed. In summary, the inclusion of 1D lumped parameter modeling to existing surgical planning methodologies may allow researchers and clinicians to better understand the impact of Fontan hemodynamics on the rest of the body.
Abstract We present ‘Smart Scribbles’—a new scribble‐based interface for user‐guided segmentation of digital sketchy drawings. In contrast to previous approaches based on simple selection strategies, Smart Scribbles exploits richer geometric and temporal information, resulting in a more intuitive segmentation interface. We introduce a novel energy minimization formulation in which both geometric and temporal information from digital input devices is used to define stroke‐to‐stroke and scribble‐to‐stroke relationships. Although the minimization of this energy is, in general, an NP‐hard problem, we use a simple heuristic that leads to a good approximation and permits an interactive system able to produce accurate labellings even for cluttered sketchy drawings. We demonstrate the power of our technique in several practical scenarios such as sketch editing, as‐rigid‐as‐possible deformation and registration, and on‐the‐fly labelling based on pre‐classified guidelines.
Single ventricle congenital heart defects, which are characterized by cyanotic mixing between the oxygenated and de-oxygenated blood, afflict 2 per every 1000 live births. These defects are surgically treated by connecting the superior and inferior vena cava to the pulmonary arteries. However, such a configuration (also known as the total cavopulmonary connection), results in high energy losses and therefore the optimization of this connection prior to the surgery could significantly improve post-operative performance. In this paper, a surgical planning framework is proposed. It is exemplified on a patient with pre and post surgical MRI data. A pediatric surgeon performed a ";virtual surgery"; on the reconstruction of the patient's anatomy prior to the actual surgery. Post-operative hemodynamics in the virtually designed post-surgical anatomy and in the actual one are computed using computational fluid dynamics and compared to each other. This framework provides the surgeon to envision numerous scenarios of possible surgical options, and accordingly predict the post operative hemodynamics.
We define b-compatibility for planar curves and propose three ball morphing techniques between pairs of b-compatible curves. Ball-morphs use the automatic ball-map correspondence, proposed by Chazal et al. [1], from which we derive different vertex trajectories (linear, circular, and parabolic). All three morphs are symmetric, meeting both curves with the same angle, which is a right angle for the circular and parabolic. We provide simple constructions for these ball-morphs and compare them to each other and other simple morphs (linear-interpolation, closest-projection, curvature-interpolation, Laplace-blending, and heat-propagation) using six cost measures (travel-distance, distortion, stretch, local acceleration, average squared mean curvature, and maximum squared mean curvature). The results depend heavily on the input curves. Nevertheless, we found that the linear ball-morph has consistently the shortest travel-distance and the circular ball-morph has the least amount of distortion.
We propose a technique to control the temporal noise present in sketchy animations. Given an input animation drawn digitally, our approach works by combining motion extraction and inbetweening techniques to generate a reduced-noise sketchy animation registered to the input animation. The amount of noise is then controlled by a continuous parameter value. Our method can be applied to effectively reduce the temporal noise present in sequences of sketches to a desired rate, while preserving the geometric richness of the sketchy style in each frame. This provides the manipulation of temporal noise as an additional artistic parameter, e.g. to emphasize character emotions and scene atmosphere, and enables the display of sketchy content to broader audiences by producing animations with comfortable noise levels. We demonstrate the effectiveness of our approach on a series of rough hand-drawn animations.
We define b-compatibility for planar curves and propose three ball morphing techniques (b-morphs) between pairs of b-compatible curves. B-morphs use the automatic ball-map correspondence, proposed by Chazal et al. [12], from which they derive vertex trajectories (Linear, Circular, Parabolic). All are symmetric, meeting both curves with the same angle, which is a right angle for the Circular and Parabolic. We provide simple constructions for these b-morphs using the maximal disks in the finite region bounded by the two curves. We compare the b-morphs to each other and to other simple morphs (Linear Interpolation (LI), Closest Projection (CP), Curvature Interpolation (CI), Laplace Blending (LB), Heat Propagation (HP)) using seven measures of quality deficiency (travel distance, distortion, stretch, local acceleration, surface area, average curvature, maximal curvature). We conclude that the ratios of these measures depends heavily on the test case, especially for LI, CI, and LB, which compute correspondence from a uniform geodesic parameterization. Nevertheless, we found that the Linear b-morph has consistently the shortest travel distance and that the Circular b-morph has the least amount of distortion.
Creating appealing shapes and silhouettes of a character's hair while maintaining the organic motion produced by physical simulation is a challenge in Disney's very stylized animated worlds. This talk describes the introduction of hierarchical sculpting controls into our hair pipeline and presents a set of tools for creating and manipulating this consistent structure to achieve art-directed hair motion. From grooming through animation, simulation and technical animation, hierarchy is leveraged both for efficiency and for preservation of the hairstyle's structure. To date this hierarchical workflow has been used on two feature productions, allowing for the efficient art-direction of a wide variety of hair types and styles.
