3D Face Recognition based on Local Conformal Parameterization and Iso-Geodesic Stripes Analysis

3D face recognition is an important topic in the field of pattern recognition and computer graphic. We propose a novel approach for 3D face recognition using local conformal parameterization and iso-geodesic stripes. In our framework, the 3D facial surface is considered as a Riemannian 2-manifold. The surface is mapped into the 2D circle parameter domain using local conformal parameterization. In the parameter domain, the geometric features are extracted from the iso-geodesic stripes. Combining the relative position measure, Chain 2D Weighted Walkthroughs (C2DWW), the 3D face matching results can be obtained. The geometric features from iso-geodesic stripes in parameter domain are robust in terms of head poses, facial expressions, and some occlusions. In the experiments, our method achieves a high recognition accuracy of 3D facial data from the Texas3D and Bosphorus3D face database.

Trends in socioeconomic inequalities in the prevalence of functional dentition among older people in Brazil

The objective of this research was to evaluate trends in socioeconomic inequalities in the prevalence of functional dentition among community-dwelling older adults in Brazil. This was a cross-sectional study with data from the last two SBBrasil Project surveys conducted in 2003 and 2010. Functional dentition was defined as the presence of 20 or more natural teeth and was assessed during the clinical examination of dentition status. Schooling was used as the socioeconomic position measure. Socioeconomic inequality was measured using two complex measures; the slope index of inequality (SII) and the relative index of inequality (RII). The prevalence of functional dentition was 10.8% (95%CI: 8.1-14.2) in 2003 and 13.6% (95%CI: 11.1-16.5) in 2010. The prevalence of functional dentition increased significantly over the educational rank in both years. Absolute inequalities were significant for both years and remained unaltered between 2003 and 2010. Significant relative inequality in the prevalence of functional dentition was found in both years of the survey. Socioeconomic inequalities in the prevalence of functional dentition among older adults in Brazil persisted significantly between both national oral health surveys.

Measuring Wear in a Fretting Test with a Confocal Microscope

Wear has been analyzed in several fretting fatigue tests with spherical contact performed on Al 7075 T651. The contact zone leaves a circular scar on the surface, which is easily detected because of the damage. Inside the contact zone, and almost concentric, another circular region called the stick zone can be distinguished. The annulus around it is called the sliding zone. The latter appears clearly damaged by wear and oxidation. The objective of this paper is to measure the size of these zones and their position, measure the wear in the sliding zone and establish a relation with the stresses at the contact. This has been done using a confocal microscope which gives a map of the surface: depth at each position. Given that the scar does not appear as an ideal circumference, the images have gone through a process of digital processing in order to obtain the geometric characteristics. Finally, the experimental data is combined with the analytical calculations through Archard wear model where a material parameter is calculated at each point in the sliding zone. It can be observed that despite the very different pressures and sliding distances in this zone, the material wear parameter is almost constant and similar to the ones in standard tests.

A new hybrid force-position measure approach on the stability for a camera robot

In order to evaluate the stability of a camera robot, a new stability performance index with combination of force and position based on the determinations of the cable tensions is proposed in this paper. First, two position factors based on the kinematic model of the camera robot are presented to show how far the specified position is away from the center of the horizontal plane at which the specified position locates within the workspace and how far the specified position is away from the top of the workspace, respectively. Then, two force factors are also developed to show the distributions of the minimum cable tensions in the specified region of the workspace. Furthermore, the stability performance index is described using the weighted method. And subsequently, the stability workspace is designed with the stability performance index. Finally, a robustness workspace with the external wrench is selected to demonstrate the effectiveness of the stability performance index above for the camera robot. Simulation results show that it is suitable to employ stability performance index to evaluate the stability of the camera robot.