31,298 research outputs found
Digital design of medical replicas via desktop systems: shape evaluation of colon parts
In this paper, we aim at providing results concerning the application of desktop systems for rapid prototyping of medical replicas
that involve complex shapes, as, for example, folds of a colon. Medical replicas may assist preoperative planning or tutoring in
surgery to better understand the interaction among pathology and organs. Major goals of the paper concern with guiding the
digital design workflow of the replicas and understanding their final performance, according to the requirements asked by the
medics (shape accuracy, capability of seeing both inner and outer details, and support and possible interfacing with other organs).
In particular, after the analysis of these requirements, we apply digital design for colon replicas, adopting two desktop systems. ,e
experimental results confirm that the proposed preprocessing strategy is able to conduct to the manufacturing of colon replicas
divided in self-supporting segments, minimizing the supports during printing. ,is allows also to reach an acceptable level of final
quality, according to the request of having a 3D presurgery overview of the problems. ,ese replicas are compared through reverse
engineering acquisitions made by a structured-light system, to assess the achieved shape and dimensional accuracy. Final results
demonstrate that low-cost desktop systems, coupled with proper strategy of preprocessing, may have shape deviation in the range
of ±1 mm, good for physical manipulations during medical diagnosis and explanation
Geometric Modeling of Cellular Materials for Additive Manufacturing in Biomedical Field: A Review
Advances in additive manufacturing technologies facilitate the fabrication of cellular materials that have tailored functional characteristics. The application of solid freeform fabrication techniques is especially exploited in designing scaffolds for tissue engineering. In this review, firstly, a classification of cellular materials from a geometric point of view is proposed; then, the main approaches on geometric modeling of cellular materials are discussed. Finally, an investigation on porous scaffolds fabricated by additive manufacturing technologies is pointed out. Perspectives in geometric modeling of scaffolds for tissue engineering are also proposed
Impervious surface estimation using remote sensing images and gis : how accurate is the estimate at subdivision level?
Impervious surface has long been accepted as a key environmental indicator linking development to its impacts on water. Many have suggested that there is a direct correlation between degree of imperviousness and both quantity and quality of water. Quantifying the amount of impervious surface, however, remains difficult and tedious especially in urban areas. Lately more efforts have been focused on the application of remote sensing and GIS technologies in assessing the amount of impervious surface and many have reported promising results at various pixel levels. This paper discusses an attempt at estimating the amount of impervious surface at subdivision level using remote sensing images and GIS techniques. Using Landsat ETM+ images and GIS techniques, a regression tree model is first developed for estimating pixel imperviousness. GIS zonal functions are then used to estimate the amount of impervious surface for a sample of subdivisions. The accuracy of the model is evaluated by comparing the model-predicted imperviousness to digitized imperviousness at the subdivision level. The paper then concludes with a discussion on the convenience and accuracy of using the method to estimate imperviousness for large areas
AlSub: Fully Parallel and Modular Subdivision
In recent years, mesh subdivision---the process of forging smooth free-form
surfaces from coarse polygonal meshes---has become an indispensable production
instrument. Although subdivision performance is crucial during simulation,
animation and rendering, state-of-the-art approaches still rely on serial
implementations for complex parts of the subdivision process. Therefore, they
often fail to harness the power of modern parallel devices, like the graphics
processing unit (GPU), for large parts of the algorithm and must resort to
time-consuming serial preprocessing. In this paper, we show that a complete
parallelization of the subdivision process for modern architectures is
possible. Building on sparse matrix linear algebra, we show how to structure
the complete subdivision process into a sequence of algebra operations. By
restructuring and grouping these operations, we adapt the process for different
use cases, such as regular subdivision of dynamic meshes, uniform subdivision
for immutable topology, and feature-adaptive subdivision for efficient
rendering of animated models. As the same machinery is used for all use cases,
identical subdivision results are achieved in all parts of the production
pipeline. As a second contribution, we show how these linear algebra
formulations can effectively be translated into efficient GPU kernels. Applying
our strategies to , Loop and Catmull-Clark subdivision shows
significant speedups of our approach compared to state-of-the-art solutions,
while we completely avoid serial preprocessing.Comment: Changed structure Added content Improved description
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