An Unified Multiscale Framework for Planar, Surface, and Curve Skeletonization

Computing skeletons of 2D shapes, and medial surface and curve skeletons of 3D shapes, is a challenging task. In particular, there is no unified framework that detects all types of skeletons using a single model, and also produces a multiscale representation which allows to progressively simplify, or regularize, all skeleton types. In this paper, we present such a framework. We model skeleton detection and regularization by a conservative mass transport process from a shape's boundary to its surface skeleton, next to its curve skeleton, and finally to the shape center. The resulting density field can be thresholded to obtain a multiscale representation of progressively simplified surface, or curve, skeletons. We detail a numerical implementation of our framework which is demonstrably stable and has high computational efficiency. We demonstrate our framework on several complex 2D and 3D shapes

Geometric Modelling and Deformation for Shape Optimization of Ship Hulls and Appendages

International audienceThe precise control of geometric models plays an important role in many domains such as computer-aided geometric design and numerical simulation. For shape optimization in computational fluid dynamics (CFD), the choice of control parameters and the way to deform a shape are critical.In this article, we describe a skeleton-based representation of shapes adapted for CFD simulation and automatic shape optimization. Instead of using the control points of a classic B-spline representation, we control the geometry in terms of architectural parameters. We assure valid shapeswith a strong shape consistency control. Deformations of the geometry are performed by solving optimization problems on the skeleton. Finally, a surface reconstruction method is proposed to evaluate the shape's performances with CFD solvers. We illustrate the approach on two problems: thefoil of an AC45 racing sail boat and the bulbous bow of a fishing trawler. For each case, we obtained a set of shape deformations and then we evaluated and analyzed the performances of the different shapes with CFD computations

Skeletonization of sparse shapes using dynamic competitive neural networks

La detección de regiones y objetos en imágenes digitales es un tema de suma importancia en la resolución de numerosos problemas correspondientes al área de reconocimiento de patrones. En esta dirección los algoritmos de esqueletización son una herramienta muy utilizada ya que permiten reducir la cantidad de información disponible facilitando la extracción de características para su posterior reconocimiento y clasificación. Además, esta transformación de la información original en sus características esenciales, facilita la eliminación de ruidos locales presentes en la entrada de datos. Este artículo propone una nueva estrategia de esqueletización aplicable a imágenes esparcidas a partir de una red neuronal competitiva dinámica entrenada con el método AVGSOM. La estrategia desarrollada en este trabajo determina los arcos que forman el esqueleto combinando el aprendizaje no supervisado del AVGSOM con un árbol de dispersión mínima (minimun spaning tree). El método propuesto ha sido aplicado en imágenes con diferente forma y grado de dispersión. En particular, los resultados obtenidos han sido comparados con soluciones existentes mostrando resultados satisfactorios. Finalmente se presentan algunas conclusiones así como algunas líneas de trabajo futurasThe detection of regions and objects in digital images is a topic of utmost importance for solving several problems related to the area of pattern recognition. In this direction, skeletonization algorithms are a widely used tool since they allow us to reduce the quantity of available data, easing the detection of characteristics for their recognition and classification. In addition, this transformation of the original data in its essential characteristics eases the elimination of local noise which is present in the data input. This paper proposes a new skeletonization strategy applicable to sparse images from a competitive, dynamic neural network trained with the AVGSOM method. The strategy developed in this paper determines the arc making up the skeleton combining AVGSOM non-supervised learning with a minimum spanning tree. The proposed method has been applied in images with different spanning shape and degree. In particular, the results obtained have been compared to existing solutions, showing successful results. Finally, some conclusions, together with some future lines of work, are presented.VII Workshop de Agentes y Sistemas Inteligentes (WASI)Red de Universidades con Carreras en Informática (RedUNCI

Utilization of Avatar-based Technology in The Area of Sign language... A Review

Information and communication technology (ICT) has progressed rapidly in recent years, and it is becoming necessary for everybody including deafpeople. This paper gives an overview of using a technology called Avatar-based technology in the area of sign language, which is the normal language of the deafworldwide, although it is different from country to another. This paper covers the basic concepts related to the signing avatar and the efforts for applying it indifferent sign language worldwide, especially Arabic Sign Language (ArSL)

Hierarchical representation of 2D polygons based on approximate skeletons

No abstract availabl

Interaction for creative applications with the Kinect v2 device

Human-Computer Interaction (HCI) is a multidisciplinary field of research that designs, evaluates and implements interactive ways of communication between computer systems and people. The evolution of different technologies in the last decades has contributed to the expansion of HCI into other fields of study as computer vision, cognitive science, psychology, industrial design, and also into interactive art. The present document contains a case of HCI in the context of interactive art. In a first step we analyse what kind of interaction can be achieved with the available equipment: a range imaging camera, a computer and a video projector. Then, three range imaging techniques capable of fulfilling our objective are studied and some devices available for purchasing and based on these techniques are compared. Thereafter, we study and compare the two acquired range imaging devices: the Kinect for Windows v1 and the Kinect for Windows v2. In a later step we build our interaction system with the Kinect for Windows v2 and we test it. We use Processing as a programming environment in order to apply creative coding and to try the different types of interaction that this device allows. Finally, with the experience gained in the previous studies and in these test, we present three final interactive programs

Image Warping Among Arbitrary Planar Shapes

Image warping refers to the 2D resampling of a source image onto a target image. Despite the variety of techniques proposed, a large class of image warping problems remains inadequately solved: mapping between two images which are delimited by arbitrary, closed, planar curves, e.g., hand-drawn curves. This paper describes a novel algorithm to perform image warping among arbitrary planar shapes whose boundary correspondences are known. A generalized polar coordinate parameterization is introduced to facilitate an efficient mapping procedure. Images are treated as collections of interior layers, extracted via a thinning process. Mapping these layers between the source and target images generates the 2D resampling grid that defines the warping. The thinning operation extends the standard polar coordinate representation to deal with arbitrary shapes