Sketch-based character prototyping by deformation

Master'sMASTER OF SCIENC

Medialness and the Perception of Visual Art

In this article we explore the practical use of medialness informed by perception studies as a representation and processing layer for describing a class of works of visual art. Our focus is towards the description of 2D objects in visual art, such as found in drawings, paintings, calligraphy, graffiti writing, where approximate boundaries or lines delimit regions associated to recognizable objects or their constitutive parts. We motivate this exploration on the one hand by considering how ideas emerging from the visual arts, cartoon animation and general drawing practice point towards the likely importance of medialness in guiding the interaction of the traditionally trained artist with the artifact. On the other hand, we also consider recent studies and results in cognitive science which point in similar directions in emphasizing the likely importance of medialness, an extension of the abstract mathematical representation known as ‘medial axis’ or ‘Voronoi graphs’, as a core feature used by humans in perceiving shapes in static or dynamic scenarios.We illustrate the use of medialness in computations performed with finished artworks as well as artworks in the process of being created, modified, or evolved through iterations. Such computations may be used to guide an artificial arm in duplicating the human creative performance or used to study in greater depth the finished artworks. Our implementations represent a prototyping of such applications of computing to art analysis and creation and remain exploratory. Our method also provides a possible framework to compare similar artworks or to study iterations in the process of producing a final preferred depiction, as selected by the artist

Geometric representation of neuroanatomical data observed in mouse brain at cellular and gross levels

This dissertation studies two problems related to geometric representation of neuroanatomical data: (i) spatial representation and organization of individual neurons, and (ii) reconstruction of three-dimensional neuroanatomical regions from sparse two-dimensional drawings. This work has been motivated by nearby development of new technology, Knife-Edge Scanning Microscopy (KESM), that images a whole mouse brain at cellular level in less than a month. A method is introduced to represent neuronal data observed in the mammalian brain at the cellular level using geometric primitives and spatial indexing. A data representation scheme is defined that captures the geometry of individual neurons using traditional geometric primitives, points and cross-sectional areas along a trajectory. This representation captures inferred synapses as directed links between primitives and spatially indexes observed neurons based on the locations of their cell bodies. This method provides a set of rules for acquisition, representation, and indexing of KESMgenerated data. Neuroanatomical data observed at the gross level provides the underlying regional framework for neuronal circuits. Accumulated expert knowledge on neuroanatomical organization is usually given as a series of sparse two-dimensional contours. A data structure and an algorithm are described to reconstruct separating surfaces among multiple regions from these sparse cross-sectional contours. A topology graph is defined for each region that describes the topological skeleton of the region’s boundary surface and that shows between which contours the surface patches should be generated. A graph-directed triangulation algorithm is provided to reconstruct surface patches between contours. This graph-directed triangulation algorithm combined together with a piecewise parametric curve fitting technique ensures that abutting or shared surface patches are precisely coincident. This method overcomes limitations in i) traditional surfaces-from-contours algorithms that assume binary, not multiple, regionalization of space, and in ii) few existing separating surfaces algorithms that assume conversion of input into a regular volumetric grid, which is not possible with sparse inter-planar resolution

HBIM parametric modelling from clouds to perform structural analyses based on finite elements: a case study on a parabolic concrete vault

3noThe paper investigates the issue of finite element model development for the structural assessment of existing structures on the basis of detailed (terrestrial laser scanning and image-based) point clouds to parametric models generated using HBIM (Heritage Building Information Modelling) technology. Different procedures and software combinations are investigated in order to provide useful hints trying to solve some of the criticalities which are still unsolved albeit the subject has been under investigation since some years now. It is worth noting that, when assets belonging to the cultural heritage domain (CH) are considered, the difficulties increase because of the peculiarity of the structural behaviour and often the singularity of the geometrical shape. The proposed methodology is presented considering the case of the “Paraboloide” of Casale (Italy), a construction from the early reinforced concrete age, which is now a relevant example of Italian concrete industrial heritage mainly due to the thin parabolic vault and the construction methodology that was so innovative for its time.openopenAbbate E.; Invernizzi S.; Spanò AntoniaAbbate, E.; Invernizzi, S.; Spanò, Antoni