The λ-medial axis was introduced in 2005 by Chazal and Lieutier as a new concept for computing the medial axis of a shape subject to filtering with a single parameter. These authors proved the stability of the λ-medial axis under small shape perturbations. In this paper, we introduce the definition of a discrete λ-medial axis (DLMA). We evaluate its stability and rotation invariance experimenta...

3D-shape description requires the partition of objects in different parts. In this paper, we propose a new approach based on the analysis of a 3D skeleton. The skeleton is a representation of objects by their axis of symmetry. In 3D, it is composed of surfaces associated to plate-like parts of the objet and curves associated to cylindrical parts. Our method is two parts. First, 4 types of skele...

Pal, S.K. and A. Rosenfeld, A fuzzy medial axis transformation based on fuzzy disks, Pattern Recognition Letters 12 (1991) 585-590. A fuzzy disk with cenler P is a fuzzy set in which membership depends only on distance from P. For any fuzzy set 1. there is a maximal fuzzy disk g~ ~j centered al every point P, and j is the sup of the g~'s. (Moreover, if j is fuzzy convex, so is every g~, bUI nOl...

Given a smooth compact codimension one submanifold S of Rk and a compact approximation K of S, we prove that it is possible to reconstruct S and to approximate the medial axis of S with topological guarantees using unions of balls centered on K . We consider two notions of noisy-approximation that generalize sampling conditions introduced by Amenta et al. and Dey et al. The first one generalize...

The Ground-based Radio Navigation System (GRNS) is an alternative/backup navigation system based on time synchronized pseudolites. It has been studied for some years due to the potential vulnerability issue of satellite navigation systems (e.g., GPS or Galileo). In the framework of our study, a periodic pulsed sequence was used instead of the randomized pulse sequence recommended as the RTCM (r...

Axial alignment is one of the main objectives in total knee arthroplasty (TKA). Computer-assisted surgery (CAS) is more accurate regarding limb alignment reconstruction compared to the conventional technique. The aim of this study was to analyse the precision of the innovative navigation system DASH® by Brainlab and to evaluate the reliability of intraoperatively acquired data. A retrospective ...

In this paper, the problem of navigation coordination is studied. New results are given for robustly integrating behavior based control systems. In the studied problem formulation, one behavior (path following) is a priori planned, the other (obstacle avoidance) is reactive. The methods are based on the virtual vehicle approach and a regularized automaton.

According to the application characteristics of the K-Rb-21Ne comagnetometer, a space-stable navigation mechanization is designed and the requirements of the comagnetometer prototype are presented. By analysing the error propagation rule of the space-stable Inertial Navigation System (INS), the three biases, the scale factor of the z-axis, and the misalignment of the x- and y-axis non-orthogona...

The purpose of the study is to develop the guidance system by the sensor fusion integration with a machine vision, an RTKGPS and a geometric direction sensor (GDS). The Extended Kalman Filter (EKF) and a statistical method based on twodimensional Probability Density Function are adopted as a fusion integration methodology in this research. To achieve the navigation planner based on sensor fusio...

Age-related declines in spatial navigation are well-known in human and non-human species. Studies in non-human species suggest that alteration in hippocampal and other neural circuitry may underlie behavioral deficits associated with aging but little is known about the neural mechanisms of human age-related decline in spatial navigation. The purpose of the present study was to examine age diffe...