Geometrical reconstruction from multiple cameras can now concurrence classical reconstruction. Shape From Silhouette (SFS)[4] is a method that estimates the Visual Hull, in real time from observed silhouette in each view. Despite the fact that SFS is really simple and robust, it produces ghost parts : a set of 3D points that does not belong to real objects. These parts can significantly disturb...

We present an algorithm to build covering polyhedra for digital 3D objects, by iteratively filling local concavities. The resulting covering polyhedron is convex and is a good approximation of the convex hull of the object. The algorithm uses 3 x 3 x 3 operators and requires a few minutes for a 128 x 128 x 128 image, when implemented on a sequential computer. Once the covering polyhedron has be...

LiDAR (Light Detection and Ranging) technology has been used to obtain geometrical attributes of tree crops in small field plots, sometimes using manual steps in data processing. The objective of this study was to develop a method for estimating canopy volume and height based on a mobile terrestrial laser scanner suited for large commercial orange groves. A 2D LiDAR sensor and a GNSS (Global Na...

In this paper a framework for defining scale-spaces, based on the computational geometry concepts of α-shapes, is proposed. In this approach, objects (curves or surfaces) of increasing convexity are computed by selective sub-sampling, from the original shape to its convex hull. The relationships with the Empirical Mode Decomposition (EMD), the curvature motion-based scale-space and some operato...

This paper proposes a solution to the problem of finding the boundary of the gamut of a color printing device or of a color image. A surface triangulation of a set of points in the color space is computed using an alpha-shape, which is a generalization of a convex hull applicable also to nonconvex solids. The desired level of detail can be controlled by means of an alpha parameter. A method for...

Given k finite point sets A1, . . . , Ak in R, we are interested in finding one translation for each point set such that the union of the translated point sets is in convex position. We show that if k is part of the input, then it is NP-hard to determine if such translations exist, even when each point set has at most three points. The original motivation of this problem comes from the question...

We propose a real-time method for simultaneously refining the reconstructed volume of a human body with loose-fitting clothing and identifying body-parts in it. Time-series volumes, which are acquired by a slow but sophisticated 3D reconstruction algorithm, with body-part labels are obtained offline. The time-series sample volumes are represented by trajectories in the eigenspaces using PCA. An...

We present a technique for the dynamic annotation of three-dimensional objects in interactive virtual environments. Annotations represent textual or symbolic descriptions providing explanatory or thematic information associated with scene objects. In contrast to techniques that treat annotations as two-dimensional view-plane elements, our technique models annotations as separate three-dimension...

A methodology is presented to systematically modify the hull shape of a ballast-free container ship, in order manage issue righting lever variation waves. The IMO second generation intact stability criteria have been identified as performance assessment tool, while vertical prismatic coefficient has selected leading parameter modifications carry out sensitivity analysis. revised Lackenby proced...