2010
Journal article
Restricted
Feature-aligned T-meshes
Myles A, Pietroni N, Kovacs D, Zorin D
High-order and regularly sampled surface representations are more efficient and compact than general meshes and considerably simplify many geometric modeling and processing algorithms. A number of recent algorithms for conversion of arbitrary meshes to regularly sampled form (typically quadrangulation) aim to align the resulting mesh with feature lines of the geometry. While resulting in a substantial improvement in mesh quality, feature alignment makes it difficult to obtain coarse regular patch partitions of the mesh. In this paper, we propose an approach to constructing patch layouts consisting of small numbers of quadrilateral patches while maintaining good feature alignment. To achieve this, we use quadrilateral T-meshes, for which the intersection of two faces may not be the whole edge or vertex, but a part of an edge. T-meshes offer more flexibility for reduction of the number of patches and vertices in a base domain while maintaining alignment with geometric features. At the same time, T-meshes retain many desirable features of quadrangulations, allowing construction of high-order representations, easy packing of regularly sampled geometric data into textures, as well as supporting different types of discretizations for physical simulation.Source: ACM TRANSACTIONS ON GRAPHICS, vol. 29 (issue 4)
DOI: 10.1145/1778765.1778854
DOI: 10.1145/1833349.1778854
Metrics:
Myles A, Pietroni N, Kovacs D, Zorin D
High-order and regularly sampled surface representations are more efficient and compact than general meshes and considerably simplify many geometric modeling and processing algorithms. A number of recent algorithms for conversion of arbitrary meshes to regularly sampled form (typically quadrangulation) aim to align the resulting mesh with feature lines of the geometry. While resulting in a substantial improvement in mesh quality, feature alignment makes it difficult to obtain coarse regular patch partitions of the mesh. In this paper, we propose an approach to constructing patch layouts consisting of small numbers of quadrilateral patches while maintaining good feature alignment. To achieve this, we use quadrilateral T-meshes, for which the intersection of two faces may not be the whole edge or vertex, but a part of an edge. T-meshes offer more flexibility for reduction of the number of patches and vertices in a base domain while maintaining alignment with geometric features. At the same time, T-meshes retain many desirable features of quadrangulations, allowing construction of high-order representations, easy packing of regularly sampled geometric data into textures, as well as supporting different types of discretizations for physical simulation.Source: ACM TRANSACTIONS ON GRAPHICS, vol. 29 (issue 4)
DOI: 10.1145/1778765.1778854
DOI: 10.1145/1833349.1778854
Metrics:
See at:
dl.acm.org 
| ACM Digital Library | ACM Transactions on Graphics | doi.org | CNR IRIS | CNR IRIS
2007
Conference article
Open Access
New techniques for computer-based simulation in surgical training
Turini G, Pietroni N, Megali G, Pietrabissa A
In the recent decades robotics and computer science have been gaining more and more relevance in all aspects of our lives. In surgery, for example, they gave birth to procedures, impossible to perform otherwise, like the tele-surgery or the nano-surgery. On this regard, these applied sciences already play an important role in assisting the surgeon both in the operative room and, as a support, in the education of young surgeons, but much work has still to be done. In fact in these last years we have seen an extreme change in the traditional training in surgery and the computer-based simulation is one of the main reason of this shift. The spread of Minimally Invasive Surgery (MIS) has brought major improvements in the quality of healthcare, but it has also increased the complexity of the surgical procedures requiring advanced and highly specialized training systems. Moreover these training procedures need to be reiterated during the operational life of surgeons. Therefore, considering the limited availability of cadavers and the public concern with the non-ethical treatment of animals, the traditional approaches to surgical training are drastically limited encouraging the use of surgical simulators based on virtual environments. Healthcare industries and the scientific community in medicine agree indicating the disruptive potential of the application of Virtual Reality (VR) to the training in the medical field. Therefore the next step is the development of surgical simulators with an high level of realism in order to practice complex procedures in a safe environment. Moreover it is decisive that this evolution is done integrating advanced medical imaging and processing, allowing surgeons to practice simulated interventions on patient specific dataset. The increasing importance of MIS techniques will cause a drastic change in pre-operation planning and basic surgical training. In fact, the features of this kind of surgical approach (the workspace limitation, the 2D vision through a laparoscopic camera and the indirect physical interaction with the patient body) make it possible to use a surgical simulator to train, plan or simulate an intervention, reproducing the visual and tactile feedback of the real surgical procedure on a real patient. This paper presents some research and applicative results on Computer Assisted Surgery (CAS) achieved in the framework of EndoCAS, a newly founded Center of Excellence in Pisa. The research has involved: the development of segmentation algorithms for volumetric datasets, the simulation of bone drilling procedures, the modeling of deformable object cuts and deformations and the simulation of rope interactions during a suture procedure in MIS. All these projects were been developed using a new open source library to support the implementation of techniques for simulating deformable objects. Our purpose is to enhance the surgical training with new improved techniques applied both to the medical imaging and to the computer-based simulation in order to carry the surgical training to a next level of realism.
Turini G, Pietroni N, Megali G, Pietrabissa A
In the recent decades robotics and computer science have been gaining more and more relevance in all aspects of our lives. In surgery, for example, they gave birth to procedures, impossible to perform otherwise, like the tele-surgery or the nano-surgery. On this regard, these applied sciences already play an important role in assisting the surgeon both in the operative room and, as a support, in the education of young surgeons, but much work has still to be done. In fact in these last years we have seen an extreme change in the traditional training in surgery and the computer-based simulation is one of the main reason of this shift. The spread of Minimally Invasive Surgery (MIS) has brought major improvements in the quality of healthcare, but it has also increased the complexity of the surgical procedures requiring advanced and highly specialized training systems. Moreover these training procedures need to be reiterated during the operational life of surgeons. Therefore, considering the limited availability of cadavers and the public concern with the non-ethical treatment of animals, the traditional approaches to surgical training are drastically limited encouraging the use of surgical simulators based on virtual environments. Healthcare industries and the scientific community in medicine agree indicating the disruptive potential of the application of Virtual Reality (VR) to the training in the medical field. Therefore the next step is the development of surgical simulators with an high level of realism in order to practice complex procedures in a safe environment. Moreover it is decisive that this evolution is done integrating advanced medical imaging and processing, allowing surgeons to practice simulated interventions on patient specific dataset. The increasing importance of MIS techniques will cause a drastic change in pre-operation planning and basic surgical training. In fact, the features of this kind of surgical approach (the workspace limitation, the 2D vision through a laparoscopic camera and the indirect physical interaction with the patient body) make it possible to use a surgical simulator to train, plan or simulate an intervention, reproducing the visual and tactile feedback of the real surgical procedure on a real patient. This paper presents some research and applicative results on Computer Assisted Surgery (CAS) achieved in the framework of EndoCAS, a newly founded Center of Excellence in Pisa. The research has involved: the development of segmentation algorithms for volumetric datasets, the simulation of bone drilling procedures, the modeling of deformable object cuts and deformations and the simulation of rope interactions during a suture procedure in MIS. All these projects were been developed using a new open source library to support the implementation of techniques for simulating deformable objects. Our purpose is to enhance the surgical training with new improved techniques applied both to the medical imaging and to the computer-based simulation in order to carry the surgical training to a next level of realism.
2010
Conference article
Open Access
Adaptive quad-mesh simplification
Bozzo A, Panozzo D, Puppo E, Pietroni N, Rocca L
We present an improved algorithm for the progressive simplification of quad meshes, which adapts the resolution of the mesh to details of the modeled shape. We extend previous work by simplifying the approach and combining it with the concept of Fitmaps. The new algorithm has several advantages: it is simpler and more robust; it does not need a parametrization of the input shape; it is adaptive; and it preserves projectability of the output mesh to the input shape, thus supporting displacement mapping. We present experimentalresults on a variety of datasets, showing relevant improvement over previous results under several aspects.
Bozzo A, Panozzo D, Puppo E, Pietroni N, Rocca L
We present an improved algorithm for the progressive simplification of quad meshes, which adapts the resolution of the mesh to details of the modeled shape. We extend previous work by simplifying the approach and combining it with the concept of Fitmaps. The new algorithm has several advantages: it is simpler and more robust; it does not need a parametrization of the input shape; it is adaptive; and it preserves projectability of the output mesh to the input shape, thus supporting displacement mapping. We present experimentalresults on a variety of datasets, showing relevant improvement over previous results under several aspects.
2013
Journal article
Restricted
Quad-mesh generation and processing: a survey
Bommes D, Levy B, Pietroni N, Puppo E, Silva C, Tarini M, Zorin D
Triangle meshes have been nearly ubiquitous in computer graphics, and a large body of data structures and geometry processing algorithms based on them has been developed in the literature. At the same time, quadrilateral meshes, especially semi-regular ones, have advantages for many applications, and significant progress was made in quadrilateral mesh generation and processing during the last several years. In this survey we discuss the advantages and problems of techniques operating on quadrilateral meshes, including surface analysis and mesh quality, simplification, adaptive refinement, alignment with features, parametrization, and remeshing.Source: COMPUTER GRAPHICS FORUM (PRINT), vol. 32 (issue 6), pp. 51-76
DOI: 10.1111/cgf.12014
Project(s): IRON
, V-MUST.NET , GOODSHAPE
Metrics:
Bommes D, Levy B, Pietroni N, Puppo E, Silva C, Tarini M, Zorin D
Triangle meshes have been nearly ubiquitous in computer graphics, and a large body of data structures and geometry processing algorithms based on them has been developed in the literature. At the same time, quadrilateral meshes, especially semi-regular ones, have advantages for many applications, and significant progress was made in quadrilateral mesh generation and processing during the last several years. In this survey we discuss the advantages and problems of techniques operating on quadrilateral meshes, including surface analysis and mesh quality, simplification, adaptive refinement, alignment with features, parametrization, and remeshing.Source: COMPUTER GRAPHICS FORUM (PRINT), vol. 32 (issue 6), pp. 51-76
DOI: 10.1111/cgf.12014
Project(s): IRON
, V-MUST.NET , GOODSHAPE Metrics:
See at:
Computer Graphics Forum | CNR IRIS | CNR IRIS
2012
Conference article
Restricted
Quad meshing
Bommes D, Levy B, Pietroni N, Puppo E, Silva C, Tarini M, Zorin D
Triangle meshes have been nearly ubiquitous in computer graphics, and a large body of data structures and geometry processing algorithms based on them has been developed in the literature. At the same time, quadrilateral meshes, especially semi-regular ones, have advantages for many applications, and significant progress was made in quadrilateral mesh generation and processing during the last several years. In this State of the Art Report, we discuss the advantages and problems of techniques operating on quadrilateral meshes, including surface analysis and mesh quality, simplification, adaptive refinement, alignment with features, parametrization, and remeshing.Project(s): V-MUST.NET
Bommes D, Levy B, Pietroni N, Puppo E, Silva C, Tarini M, Zorin D
Triangle meshes have been nearly ubiquitous in computer graphics, and a large body of data structures and geometry processing algorithms based on them has been developed in the literature. At the same time, quadrilateral meshes, especially semi-regular ones, have advantages for many applications, and significant progress was made in quadrilateral mesh generation and processing during the last several years. In this State of the Art Report, we discuss the advantages and problems of techniques operating on quadrilateral meshes, including surface analysis and mesh quality, simplification, adaptive refinement, alignment with features, parametrization, and remeshing.Project(s): V-MUST.NET
2014
Journal article
Open Access
Robust field-aligned global parametrization
Myles A, Pietroni N, Zorin D
We present a robust method for computing locally bijective global parametrizations aligned with a given cross-field. The singularities of the parametrization in general agree with singularities of the field, except in a small number of cases when several additional cones need to be added in a controlled way. Parametric lines can be constrained to follow an arbitrary set of feature lines on the surface. Our method is based on constructing an initial quad patch partition using robust cross-field integral line tracing. This process is followed by an algorithm modifying the quad layout structure to ensure that consistent parametric lengths can be assigned to the edges. For most meshes, the layout modification algorithm does not add new singularities; a small number of singularities may be added to resolve an explicitly described set of layouts. We demonstrate that our algorithm succeeds on a test data set of over a hundred meshes. Copyright © ACM.Source: ACM TRANSACTIONS ON GRAPHICS, vol. 33 (issue 4)
DOI: 10.1145/2601097.2601154
Metrics:
Myles A, Pietroni N, Zorin D
We present a robust method for computing locally bijective global parametrizations aligned with a given cross-field. The singularities of the parametrization in general agree with singularities of the field, except in a small number of cases when several additional cones need to be added in a controlled way. Parametric lines can be constrained to follow an arbitrary set of feature lines on the surface. Our method is based on constructing an initial quad patch partition using robust cross-field integral line tracing. This process is followed by an algorithm modifying the quad layout structure to ensure that consistent parametric lengths can be assigned to the edges. For most meshes, the layout modification algorithm does not add new singularities; a small number of singularities may be added to resolve an explicitly described set of layouts. We demonstrate that our algorithm succeeds on a test data set of over a hundred meshes. Copyright © ACM.Source: ACM TRANSACTIONS ON GRAPHICS, vol. 33 (issue 4)
DOI: 10.1145/2601097.2601154
Metrics:
See at:
ACM Transactions on Graphics 
| ACM Transactions on Graphics | CNR IRIS | www.scopus.com
2007
Journal article
Restricted
Texturing internal surfaces from a few cross sections
Pietroni N, Otaduy M, Bickel B, Ganovelli F, Gross M
We introduce a new appearance-modeling paradigm for synthesizing the internal structure of a 3D model from photographs of a few cross-sections of a real object. When the internal surfaces of the 3D model are revealed as it is cut, carved, or simply clipped, we synthesize their texture from the input photographs. Our texture synthesis algorithm is best classified as a morphing technique, which efficiently outputs the texture attributes of each surface point on demand. For determining source points and their weights in the morphing algorithm, we propose an interpolation domain based on BSP trees that naturally resembles planar splitting of real objects. In the context of the interpolation domain, we define efficient warping and morphing operations that allow for real-time synthesis of textures. Overall, our modeling paradigm, together with its realization through our texture synthesis algorithm, allow users to author 3D models that reveal highly realistic internal surfaces in a variety of artistic flavors.Source: COMPUTER GRAPHICS FORUM (PRINT), vol. 26 (issue 3), pp. 637-644
DOI: 10.1111/j.1467-8659.2007.01087.x
Metrics:
Pietroni N, Otaduy M, Bickel B, Ganovelli F, Gross M
We introduce a new appearance-modeling paradigm for synthesizing the internal structure of a 3D model from photographs of a few cross-sections of a real object. When the internal surfaces of the 3D model are revealed as it is cut, carved, or simply clipped, we synthesize their texture from the input photographs. Our texture synthesis algorithm is best classified as a morphing technique, which efficiently outputs the texture attributes of each surface point on demand. For determining source points and their weights in the morphing algorithm, we propose an interpolation domain based on BSP trees that naturally resembles planar splitting of real objects. In the context of the interpolation domain, we define efficient warping and morphing operations that allow for real-time synthesis of textures. Overall, our modeling paradigm, together with its realization through our texture synthesis algorithm, allow users to author 3D models that reveal highly realistic internal surfaces in a variety of artistic flavors.Source: COMPUTER GRAPHICS FORUM (PRINT), vol. 26 (issue 3), pp. 637-644
DOI: 10.1111/j.1467-8659.2007.01087.x
Metrics:
See at:
diglib.eg.org | Computer Graphics Forum | CNR IRIS | CNR IRIS
2005
Conference article
Restricted
Robust segmentation of anatomical structures with deformable surfaces and marching cubes
Pietroni N, Giachetti A, Ganovelli F
Computer assisted medical applications require often the reconstruction of anatomical structures to compute parameters useful for diagnosis or interventional planning. From CT and MRI datasets it is possible to obtain surface models of the organs of interest with a variety of algorithms, like Marching Cubes, level sets or deformable parametric surfaces. Each technique has advantages but also drawbacks like noise sensitivity (isosurface extraction), risk of leakages (level sets), oversmoothing and impossible handling of topological changes (Deformable models). To obtain a good trade-off between robustness, shape constraints and topological control, we propose a 3D balloon/isosurface method joining the advantages in curvature control, leakage penalization and efficiency of parametric surfaces with a fast re-parametrization handling topological changes. It is based on the control of surface self-intersections, freezing of the intersected nodes and replacement of the final mesh with an isosurface computed on a field representing the signed distance from the true surface.
Pietroni N, Giachetti A, Ganovelli F
Computer assisted medical applications require often the reconstruction of anatomical structures to compute parameters useful for diagnosis or interventional planning. From CT and MRI datasets it is possible to obtain surface models of the organs of interest with a variety of algorithms, like Marching Cubes, level sets or deformable parametric surfaces. Each technique has advantages but also drawbacks like noise sensitivity (isosurface extraction), risk of leakages (level sets), oversmoothing and impossible handling of topological changes (Deformable models). To obtain a good trade-off between robustness, shape constraints and topological control, we propose a 3D balloon/isosurface method joining the advantages in curvature control, leakage penalization and efficiency of parametric surfaces with a fast re-parametrization handling topological changes. It is based on the control of surface self-intersections, freezing of the intersected nodes and replacement of the final mesh with an isosurface computed on a field representing the signed distance from the true surface.
2007
Conference article
Restricted
A robust method for real-time thread simulation
Kubiak B, Pietroni N, Ganovelli F, Fratarcangeli M
We present a physically based model for real-time simulation of thread dynamics. Our model captures all the relevant aspects of the physics of the thread, including quasi-zero elasticit, bending, torsion and self-collision, and it provides output forces for the haptic feedback. The physical properties are modeled in terms of constraints that are iteratively satisfied while the numerical integration is carried out through a Verlet scheme. This approach leads to an unconditionally stable, controllable and computationally light simulation. Our results demonstrate the effectiveness of our model, showing the interaction of the thread with other objects in real time and the creation of complex knots.
Kubiak B, Pietroni N, Ganovelli F, Fratarcangeli M
We present a physically based model for real-time simulation of thread dynamics. Our model captures all the relevant aspects of the physics of the thread, including quasi-zero elasticit, bending, torsion and self-collision, and it provides output forces for the haptic feedback. The physical properties are modeled in terms of constraints that are iteratively satisfied while the numerical integration is carried out through a Verlet scheme. This approach leads to an unconditionally stable, controllable and computationally light simulation. Our results demonstrate the effectiveness of our model, showing the interaction of the thread with other objects in real time and the creation of complex knots.
See at:
dl.acm.org | CNR IRIS | CNR IRIS
2005
Contribution to conference
Restricted
Robust segmentation of anatomical structures with deformable surfaces and marching cubes
Pietroni N, Ganovelli F, Giachetti A
Computer assisted medical applications require often the reconstruction of anatomical structures to compute parameters useful for diagnosis or interventional planning. From CT and MRI datasets it is possible to obtain surface models of the organs of interest with a variety of algorithms, like Marching Cubes, level sets or deformable parametric surfaces. Each technique has advantages but also drawbacks like noise sensitivity (isosurface extraction), risk of leakages (level sets), oversmoothing and impossible handling of topological changes (Deformable models). To obtain a good trade-off between robustness, shape constraints and topological control, we propose a 3D balloon/isosurface method joining the advantages in curvature control, leakage penalization and efficiency of parametric surfaces with a fast re-parametrization handling topological changes. It is based on the control of surface self-intersections, freezing of the intersected nodes and replacement of the final mesh with an isosurface computed on a field representing the signed distance from the true surface.
Pietroni N, Ganovelli F, Giachetti A
Computer assisted medical applications require often the reconstruction of anatomical structures to compute parameters useful for diagnosis or interventional planning. From CT and MRI datasets it is possible to obtain surface models of the organs of interest with a variety of algorithms, like Marching Cubes, level sets or deformable parametric surfaces. Each technique has advantages but also drawbacks like noise sensitivity (isosurface extraction), risk of leakages (level sets), oversmoothing and impossible handling of topological changes (Deformable models). To obtain a good trade-off between robustness, shape constraints and topological control, we propose a 3D balloon/isosurface method joining the advantages in curvature control, leakage penalization and efficiency of parametric surfaces with a fast re-parametrization handling topological changes. It is based on the control of surface self-intersections, freezing of the intersected nodes and replacement of the final mesh with an isosurface computed on a field representing the signed distance from the true surface.
2007
Software
Metadata Only Access
IDOLib: Interactive Deformable Objects Library
Ganovelli F, Turini G, Pietroni N
IDOLib è una libreria scritta in C++ per lo sviluppo di software di modellazione di oggetti deformabili. La libreria offre gli strumenti di base per sviluppare metodi per la modellazione di oggetti deformabili: definizioni geometriche ed operazioni di algebra lineare, metodi di integrazione numerica di equazioni differenziali parziali
Ganovelli F, Turini G, Pietroni N
IDOLib è una libreria scritta in C++ per lo sviluppo di software di modellazione di oggetti deformabili. La libreria offre gli strumenti di base per sviluppare metodi per la modellazione di oggetti deformabili: definizioni geometriche ed operazioni di algebra lineare, metodi di integrazione numerica di equazioni differenziali parziali
See at:
CNR IRIS
2011
Journal article
Open Access
Global parametrization of range image sets
Pietroni N, Tarini M, Sorkine O, Zorin D
We present a method to globally parameterize a surface represented by height maps over a set of planes (range images). In contrast to other parametrization techniques, we do not start with a manifold mesh. The parametrization we compute defines a manifold structure, it is seamless and globally smooth, can be aligned to geometric features and shows good quality in terms of angle and area preservation, comparable to current parametrization techniques for meshes. Computing such global seamless parametrization makes it possible to perform quad remeshing, texture mapping and texture synthesis and many other types of geometry processing operations. Our approach is based on a formulation of the Poisson equation on a manifold structure defined for the surface by the range images. Construction of such global parametrization requires only a way to project surface data onto a set of planes, and can be applied directly to implicit surfaces, nonmanifold surfaces, very large meshes, and collections of range scans. We demonstrate application of our technique to all these geometry types.Source: ACM TRANSACTIONS ON GRAPHICS (ONLINE), vol. 30 (issue 6)
DOI: 10.1145/2070781.2024183
DOI: 10.1145/2024156.2024183
Project(s): HCC: Medium: Robust and Accurate Modeling with Multifield Geometry, V-MUST.NET
Metrics:
Pietroni N, Tarini M, Sorkine O, Zorin D
We present a method to globally parameterize a surface represented by height maps over a set of planes (range images). In contrast to other parametrization techniques, we do not start with a manifold mesh. The parametrization we compute defines a manifold structure, it is seamless and globally smooth, can be aligned to geometric features and shows good quality in terms of angle and area preservation, comparable to current parametrization techniques for meshes. Computing such global seamless parametrization makes it possible to perform quad remeshing, texture mapping and texture synthesis and many other types of geometry processing operations. Our approach is based on a formulation of the Poisson equation on a manifold structure defined for the surface by the range images. Construction of such global parametrization requires only a way to project surface data onto a set of planes, and can be applied directly to implicit surfaces, nonmanifold surfaces, very large meshes, and collections of range scans. We demonstrate application of our technique to all these geometry types.Source: ACM TRANSACTIONS ON GRAPHICS (ONLINE), vol. 30 (issue 6)
DOI: 10.1145/2070781.2024183
DOI: 10.1145/2024156.2024183
Project(s): HCC: Medium: Robust and Accurate Modeling with Multifield Geometry
, V-MUST.NET Metrics:
See at:
Archivio istituzionale della ricerca - Università dell'Insubria | ACM Transactions on Graphics | doi.org | ACM Transactions on Graphics | CNR IRIS | CNR IRIS | www.scopus.com
2011
Journal article
Open Access
Simple quad domains for field aligned mesh parametrization
Tarini M, Puppo E, Panozzi D, Pietroni N, Cignoni P
We present a method for the global parametrization of meshes that preserves alignment to a cross field in input while obtaining a parametric domain made of few coarse axis-aligned rectangular patches,which form an abstract base complex without T-junctions. The method is based on the topological simplification of the cross field in input, followed by global smoothingSource: ACM TRANSACTIONS ON GRAPHICS (ONLINE), vol. 30 (issue 16)
DOI: 10.1145/2024156.2024176
DOI: 10.1145/2070781.2024176
Project(s): V-MUST.NET
Metrics:
Tarini M, Puppo E, Panozzi D, Pietroni N, Cignoni P
We present a method for the global parametrization of meshes that preserves alignment to a cross field in input while obtaining a parametric domain made of few coarse axis-aligned rectangular patches,which form an abstract base complex without T-junctions. The method is based on the topological simplification of the cross field in input, followed by global smoothingSource: ACM TRANSACTIONS ON GRAPHICS (ONLINE), vol. 30 (issue 16)
DOI: 10.1145/2024156.2024176
DOI: 10.1145/2070781.2024176
Project(s): V-MUST.NET
Metrics:
See at:
Archivio istituzionale della ricerca - Università dell'Insubria | ACM Transactions on Graphics | doi.org | ACM Transactions on Graphics | CNR IRIS | CNR IRIS | www.scopus.com
2011
Journal article
Restricted
New techniques for computer-based simulation in surgical training
Turini Giuseppe, Pietroni Nico, Megali Giuseppe, Ganovelli Fabio, Pietrabissa Andrea, Mosca Franco
In the recent decades robotics and computer science have been gaining more and more relevance in all aspects of our lives. In surgery, for example, they gave birth to procedures, impossible to perform otherwise, like the tele-surgery or the nano-surgery. On this regard, these applied sciences already play an important role in assisting the surgeon both in the operative room and, as a support, in the education of young surgeons, but much work has still to be done. In fact in these last years we have seen an extreme change in the traditional training in surgery and the computer-based simulation is one of the main reason of this shift. The spread of Minimally Invasive Surgery (MIS) has brought major improvements in the quality of healthcare, but it has also increased the complexity of the surgical procedures requiring advanced and highly specialized training systems. Moreover these training procedures need to be reiterated during the operational life of surgeons. Therefore, considering the limited availability of cadavers and the public concern with the non-ethical treatment of animals, the traditional approaches to surgical training are drastically limited encouraging the use of surgical simulators based on virtual environments. Healthcare industries and the scientific community in medicine agree indicating the disruptive potential of the application of Virtual Reality (VR) to the training in the medical field. Therefore the next step is the development of surgical simulators with an high level of realism in order to practice complex procedures in a safe environment. Moreover it is decisive that this evolution is done integrating advanced medical imaging and processing, allowing surgeons to practice simulated interventions on patient specific dataset. The increasing importance of MIS techniques will cause a drastic change in pre-operation planning and basic surgical training. In fact, the features of this kind of surgical approach (the workspace limitation, the 2D vision through a laparoscopic camera and the indirect physical interaction with the patient body) make it possible to use a surgical simulator to train, plan or simulate an intervention, reproducing the visual and tactile feedback of the real surgical procedure on a real patient. This paper presents some research and applicative results on Computer Assisted Surgery (CAS) achieved in the framework of EndoCAS, a newly founded Center of Excellence in Pisa. The research has involved: the development of segmentation algorithms for volumetric datasets, the simulation of bone drilling procedures, the modeling of deformable object cuts and deformations and the simulation of rope interactions during a suture procedure in MIS. All these projects were been developed using a new open source library to support the implementation of techniques for simulating deformable objects. Our purpose is to enhance the surgical training with new improved techniques applied both to the medical imaging and to the computer-based simulation in order to carry the surgical training to a next level of realism.Source: INTERNATIONAL JOURNAL OF BIOMEDICAL ENGINEERING AND TECHNOLOGY, vol. 5 (issue 4), pp. 303-316
DOI: 10.1504/ijbet.2011.039923
Metrics:
Turini Giuseppe, Pietroni Nico, Megali Giuseppe, Ganovelli Fabio, Pietrabissa Andrea, Mosca Franco
In the recent decades robotics and computer science have been gaining more and more relevance in all aspects of our lives. In surgery, for example, they gave birth to procedures, impossible to perform otherwise, like the tele-surgery or the nano-surgery. On this regard, these applied sciences already play an important role in assisting the surgeon both in the operative room and, as a support, in the education of young surgeons, but much work has still to be done. In fact in these last years we have seen an extreme change in the traditional training in surgery and the computer-based simulation is one of the main reason of this shift. The spread of Minimally Invasive Surgery (MIS) has brought major improvements in the quality of healthcare, but it has also increased the complexity of the surgical procedures requiring advanced and highly specialized training systems. Moreover these training procedures need to be reiterated during the operational life of surgeons. Therefore, considering the limited availability of cadavers and the public concern with the non-ethical treatment of animals, the traditional approaches to surgical training are drastically limited encouraging the use of surgical simulators based on virtual environments. Healthcare industries and the scientific community in medicine agree indicating the disruptive potential of the application of Virtual Reality (VR) to the training in the medical field. Therefore the next step is the development of surgical simulators with an high level of realism in order to practice complex procedures in a safe environment. Moreover it is decisive that this evolution is done integrating advanced medical imaging and processing, allowing surgeons to practice simulated interventions on patient specific dataset. The increasing importance of MIS techniques will cause a drastic change in pre-operation planning and basic surgical training. In fact, the features of this kind of surgical approach (the workspace limitation, the 2D vision through a laparoscopic camera and the indirect physical interaction with the patient body) make it possible to use a surgical simulator to train, plan or simulate an intervention, reproducing the visual and tactile feedback of the real surgical procedure on a real patient. This paper presents some research and applicative results on Computer Assisted Surgery (CAS) achieved in the framework of EndoCAS, a newly founded Center of Excellence in Pisa. The research has involved: the development of segmentation algorithms for volumetric datasets, the simulation of bone drilling procedures, the modeling of deformable object cuts and deformations and the simulation of rope interactions during a suture procedure in MIS. All these projects were been developed using a new open source library to support the implementation of techniques for simulating deformable objects. Our purpose is to enhance the surgical training with new improved techniques applied both to the medical imaging and to the computer-based simulation in order to carry the surgical training to a next level of realism.Source: INTERNATIONAL JOURNAL OF BIOMEDICAL ENGINEERING AND TECHNOLOGY, vol. 5 (issue 4), pp. 303-316
DOI: 10.1504/ijbet.2011.039923
Metrics:
See at:
International Journal of Biomedical Engineering and Technology | CNR IRIS | CNR IRIS | www.inderscience.com
2011
Journal article
Open Access
Automatic construction of quad-based subdivision surfaces using fitmaps
Daniele Panozzo, Enrico Puppo, Marco Tarini, Nico Pietroni, Paolo Cignoni
We present an automatic method to produce a Catmull-Clark subdivision surface that fits a given input mesh. Its control mesh is coarse and adaptive, and it is obtained by simplifying an initial mesh at high resolution. Simplification occurs progressively via local operators and addresses both quality of surface and faithfulness to the input shape throughout the whole process. The method is robust and performs well on rather complex shapes. Displacement mapping or normal mapping can be applied to approximate the input shape arbitrarily well.Source: IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS, vol. 17 (issue 10), pp. 1510-1520
DOI: 10.1109/tvcg.2011.28
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Daniele Panozzo, Enrico Puppo, Marco Tarini, Nico Pietroni, Paolo Cignoni
We present an automatic method to produce a Catmull-Clark subdivision surface that fits a given input mesh. Its control mesh is coarse and adaptive, and it is obtained by simplifying an initial mesh at high resolution. Simplification occurs progressively via local operators and addresses both quality of surface and faithfulness to the input shape throughout the whole process. The method is robust and performs well on rather complex shapes. Displacement mapping or normal mapping can be applied to approximate the input shape arbitrarily well.Source: IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS, vol. 17 (issue 10), pp. 1510-1520
DOI: 10.1109/tvcg.2011.28
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IEEE Transactions on Visualization and Computer Graphics | IEEE Transactions on Visualization and Computer Graphics | CNR IRIS | ieeexplore.ieee.org | CNR IRIS
2013
Journal article
Restricted
Animation-aware quadrangulation
Marcias G, Pietroni N, Panozzo D, Puppo E, Sorkine O
Geometric meshes that model animated characters must be designed while taking into account the deformations that the shape will undergo during animation. We analyze an input sequence of meshes with point-to-point correspondence, and we automatically produce a quadrangular mesh that fits well the input animation. We first analyze the local deformation that the surface undergoes at each point, and we initialize a cross field that remains as aligned as possible to the principal directions of deformation throughout the sequence. We then smooth this cross field based on an energy that uses a weighted combination of the initial field and the local amount of stretch. Finally, we compute a field-aligned quadrangulation with an off-the-shelf method. Our technique is fast and very simple to implement, and it significantly improves the quality of the output quad mesh and its suitability for character animation, compared to creating the quad mesh based on a single pose. We present experimental results and comparisons with a state-of-the-art quadrangulation method, on both sequences from 3D scanning and synthetic sequences obtained by a rough animation of a triangulated model.Source: COMPUTER GRAPHICS FORUM (ONLINE), vol. 32 (issue 5), pp. 167-175
DOI: 10.1111/cgf.12183
Project(s): IMODEL, V-MUST.NET
Metrics:
Marcias G, Pietroni N, Panozzo D, Puppo E, Sorkine O
Geometric meshes that model animated characters must be designed while taking into account the deformations that the shape will undergo during animation. We analyze an input sequence of meshes with point-to-point correspondence, and we automatically produce a quadrangular mesh that fits well the input animation. We first analyze the local deformation that the surface undergoes at each point, and we initialize a cross field that remains as aligned as possible to the principal directions of deformation throughout the sequence. We then smooth this cross field based on an energy that uses a weighted combination of the initial field and the local amount of stretch. Finally, we compute a field-aligned quadrangulation with an off-the-shelf method. Our technique is fast and very simple to implement, and it significantly improves the quality of the output quad mesh and its suitability for character animation, compared to creating the quad mesh based on a single pose. We present experimental results and comparisons with a state-of-the-art quadrangulation method, on both sequences from 3D scanning and synthetic sequences obtained by a rough animation of a triangulated model.Source: COMPUTER GRAPHICS FORUM (ONLINE), vol. 32 (issue 5), pp. 167-175
DOI: 10.1111/cgf.12183
Project(s): IMODEL
, V-MUST.NET Metrics:
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2011
Conference article
Open Access
Simple quad domains for field aligned mesh parametrization
Tarini M, Puppo E, Panozzi D, Pietroni N, Cignoni P
We present a method for the global parametrization of meshes that preserves alignment to a cross field in input while obtaining a parametric domain made of few coarse axis-aligned rectangular patches, which form an abstract base complex without T-junctions. The method is based on the topological simplification of the cross field in input, followed by global smoothing.DOI: 10.1145/2024156.2024176
DOI: 10.1145/2070781.2024176
Project(s): V-MUST.NET
Metrics:
Tarini M, Puppo E, Panozzi D, Pietroni N, Cignoni P
We present a method for the global parametrization of meshes that preserves alignment to a cross field in input while obtaining a parametric domain made of few coarse axis-aligned rectangular patches, which form an abstract base complex without T-junctions. The method is based on the topological simplification of the cross field in input, followed by global smoothing.DOI: 10.1145/2024156.2024176
DOI: 10.1145/2070781.2024176
Project(s): V-MUST.NET
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Archivio istituzionale della ricerca - Università dell'Insubria | ACM Transactions on Graphics | dl.acm.org | doi.org | ACM Transactions on Graphics | CNR IRIS | CNR IRIS | www.scopus.com
2016
Conference article
Restricted
State of the art on functional fabrication
Medeiros E Sá A, Rodriguezechavarria K, Pietroni N, Cignoni P
Digital fabrication technologies are becoming of importance to a number of knowledge areas and sectors, including medicine, entertainment, design, engineering, education, arts and architecture, due to their accessibility and versatility. These technolo- gies are changing the design of digital models, materials and manufacturing processes which enable to build previously un- achievable physical objects. Since many constraints imposed on the design of objects have changed significantly, a growing research community is working on graphical tools and techniques to enable the conception, automation, production and usage of innovative and complex designs for fabrication. In the present work, we survey the state of the art of computer graphics contributions to functional fabrication design tools and techniques. By functional fabrication we understand the design and manufacture of physical objects which functionalities exploit the capabilities of digital fabrication technologies. These func- tionalities include improving the mechanics of a workpiece, producing articulated models, capturing aerodynamics, planning deformable workpieces and controlling the object's appearance and acoustics. The resulting design tools are clearly taking advantage of relevant computer graphics techniques. Furthermore, they are extending these techniques to realise new physical forms as well as bringing innovation to feed into the design space.DOI: 10.2312/gdf.20161073
Metrics:
Medeiros E Sá A, Rodriguezechavarria K, Pietroni N, Cignoni P
Digital fabrication technologies are becoming of importance to a number of knowledge areas and sectors, including medicine, entertainment, design, engineering, education, arts and architecture, due to their accessibility and versatility. These technolo- gies are changing the design of digital models, materials and manufacturing processes which enable to build previously un- achievable physical objects. Since many constraints imposed on the design of objects have changed significantly, a growing research community is working on graphical tools and techniques to enable the conception, automation, production and usage of innovative and complex designs for fabrication. In the present work, we survey the state of the art of computer graphics contributions to functional fabrication design tools and techniques. By functional fabrication we understand the design and manufacture of physical objects which functionalities exploit the capabilities of digital fabrication technologies. These func- tionalities include improving the mechanics of a workpiece, producing articulated models, capturing aerodynamics, planning deformable workpieces and controlling the object's appearance and acoustics. The resulting design tools are clearly taking advantage of relevant computer graphics techniques. Furthermore, they are extending these techniques to realise new physical forms as well as bringing innovation to feed into the design space.DOI: 10.2312/gdf.20161073
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diglib.eg.org | CNR IRIS | CNR IRIS
2019
Journal article
Open Access
QuadMixer: layout preserving blending of quadrilateral meshes
Nuvoli S, Hernandez A, Esperança C, Scateni R, Cignoni P, Pietroni N
We propose QuadMixer, a novel interactive technique to compose quad mesh components preserving the majority of the original layouts. Quad Layout is a crucial property for many applications since it conveys important information that would otherwise be destroyed by techniques that aim only at preserving shape. Our technique keeps untouched all the quads in the patches which are not involved in the blending. We first perform robust boolean operations on the corresponding triangle meshes. Then we use this result to identify and build new surface patches for small regions neighboring the intersection curves. These blending patches are carefully quadrangulated respecting boundary constraints and stitched back to the untouched parts of the original models. The resulting mesh preserves the designed edge flow that, by construction, is captured and incorporated to the new quads as much as possible. We present our technique in an interactive tool to show its usability and robustness.Source: ACM TRANSACTIONS ON GRAPHICS, vol. 38 (issue 6), pp. 180:1-180:13
DOI: 10.1145/3355089.3356542
Metrics:
Nuvoli S, Hernandez A, Esperança C, Scateni R, Cignoni P, Pietroni N
We propose QuadMixer, a novel interactive technique to compose quad mesh components preserving the majority of the original layouts. Quad Layout is a crucial property for many applications since it conveys important information that would otherwise be destroyed by techniques that aim only at preserving shape. Our technique keeps untouched all the quads in the patches which are not involved in the blending. We first perform robust boolean operations on the corresponding triangle meshes. Then we use this result to identify and build new surface patches for small regions neighboring the intersection curves. These blending patches are carefully quadrangulated respecting boundary constraints and stitched back to the untouched parts of the original models. The resulting mesh preserves the designed edge flow that, by construction, is captured and incorporated to the new quads as much as possible. We present our technique in an interactive tool to show its usability and robustness.Source: ACM TRANSACTIONS ON GRAPHICS, vol. 38 (issue 6), pp. 180:1-180:13
DOI: 10.1145/3355089.3356542
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ISTI Repository | ACM Transactions on Graphics | doi.acm.org | ACM Transactions on Graphics | CNR IRIS | CNR IRIS | CNR IRIS
2019
Patent
Restricted
System and method of performing operations on quadrilateral mesh objects
Pietroni N., Nuvoli S., Cignoni P., Scateni R.
A system and method of performing an operation on a pair of quadrilateral mesh objects. The method comprises dividing quadrilateral elements of the pair of quadrilateral meshes into triangles and performing the operation using the triangles, the operation generating a triangular mesh object (205); and determining a new patch partition of the generated triangulated mesh object for a region of triangles of the generated triangular mesh object affected by the operation, the new patch partition determined based on determining a cross field of the region and polyline tracing using the cross field (210). The method also comprises performing quadrangulation (220) to generate a new quadrilateral mesh object based on the patch partition.
Pietroni N., Nuvoli S., Cignoni P., Scateni R.
A system and method of performing an operation on a pair of quadrilateral mesh objects. The method comprises dividing quadrilateral elements of the pair of quadrilateral meshes into triangles and performing the operation using the triangles, the operation generating a triangular mesh object (205); and determining a new patch partition of the generated triangulated mesh object for a region of triangles of the generated triangular mesh object affected by the operation, the new patch partition determined based on determining a cross field of the region and polyline tracing using the cross field (210). The method also comprises performing quadrangulation (220) to generate a new quadrilateral mesh object based on the patch partition.
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CNR IRIS | ipsearch.ipaustralia.gov.au | CNR IRIS