Vision-based portuguese sign language recognition system

Vision-based hand gesture recognition is an area of active current research in computer vision and machine learning. Being a natural way of human interaction, it is an area where many researchers are working on, with the goal of making human computer interaction (HCI) easier and natural, without the need for any extra devices. So, the primary goal of gesture recognition research is to create systems, which can identify specific human gestures and use them, for example, to convey information. For that, vision-based hand gesture interfaces require fast and extremely robust hand detection, and gesture recognition in real time. Hand gestures are a powerful human communication modality with lots of potential applications and in this context we have sign language recognition, the communication method of deaf people. Sign lan- guages are not standard and universal and the grammars differ from country to coun- try. In this paper, a real-time system able to interpret the Portuguese Sign Language is presented and described. Experiments showed that the system was able to reliably recognize the vowels in real-time, with an accuracy of 99.4% with one dataset of fea- tures and an accuracy of 99.6% with a second dataset of features. Although the im- plemented solution was only trained to recognize the vowels, it is easily extended to recognize the rest of the alphabet, being a solid foundation for the development of any vision-based sign language recognition user interface system

Sub-surface Oxygen and Surface Oxide Formation at Ag(111): A Density-functional Theory Investigation

To help provide insight into the remarkable catalytic behavior of the oxygen/silver system for heterogeneous oxidation reactions, purely sub-surface oxygen, and structures involving both on-surface and sub-surface oxygen, as well as oxide-like structures at the Ag(111) surface have been studied for a wide range of coverages and adsorption sites using density-functional theory. Adsorption on the surface in fcc sites is energetically favorable for low coverages, while for higher coverage a thin surface-oxide structure is energetically favorable. This structure has been proposed to correspond to the experimentally observed (4x4) phase. With increasing O concentrations, thicker oxide-like structures resembling compressed Ag2O(111) surfaces are energetically favored. Due to the relatively low thermal stability of these structures, and the very low sticking probability of O2 at Ag(111), their formation and observation may require the use of atomic oxygen (or ozone, O3) and low temperatures. We also investigate diffusion of O into the sub-surface region at low coverage (0.11 ML), and the effect of surface Ag vacancies in the adsorption of atomic oxygen and ozone-like species. The present studies, together with our earlier investigations of on-surface and surface-substitutional adsorption, provide a comprehensive picture of the behavior and chemical nature of the interaction of oxygen and Ag(111), as well as of the initial stages of oxide formation.Comment: 17 pages including 14 figures, Related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm

Recognizing Human Postures and Poses in Monocular Still Images

In this paper, person detection with simultaneous or subsequent human body posture recognition is achieved using parts-based models, since the search space for typical poses is much smaller than the kinematics space. Posture recovery is carried out by detecting the human body, its posture and orientation at the same time. Since features of different human postures can be expected to have some shared subspace against the non-person class, detection and classification simultaneously is tenable. Contrary to many related efforts, we focus on postures that cannot be easily distinguished after segmentation by their aspect ratio or silhouette, but rather require a texture-based feature vector. The approaches presented do not rely on explicit models nor on labeling individual body parts. Both the detection and classification are performed in one pass on the image, where the score of the detection is an ensemble of votes from parts patches

Professional Natural Interfaces for Medicine Applications

This article focuses on the problems of development of control systems and medical equipment medical professional interfaces. In our paper we propose a solution to the problem, using gesture language and contact-less motion capture. © Springer International Publishing Switzerland 2014

Culturally Independent Gestures for In-Car Interactions

Abstract. In this paper we report on our ongoing work to introduce freehand gestures in cars as an alternative input modality. Contactless gestures have hardly been successful in cars so far, but have received attention in other contexts recently. We propose a way to achieve a better acceptance by both drivers and car manufacturers. Using a four-step process, we developed a small set of culturally independent and therefore easy-to-learn gestures, which can be used universally across different devices. We built a first prototype using distance sensors to detect the stop gesture in front of several devices. We conducted a user study during actual driving situations, testing the pragmatic and hedonic quality of the approach as well as its attractiveness. The results show a high acceptance of our approach and confirm the potential of freehand gestures as an alternative input modality in the car

Dynamic Interaction Plugins Deployment in Ambient Spaces

Part 1: Research PapersInternational audienceA large-scale dynamic runtime deployment of existing and future interaction techniques remains an enduring challenge for engineering real-world pervasive computing ecosystems (ambient spaces). The need for innovative engineering solutions to tackle this issue increases, due to the ever expanding landscape of novel natural interaction techniques proposed every year to enrich interactive eco-systems with multitouch gestures, motion gestures, full body in motion, etc. In this paper, we discuss the implementation of Interaction Plugins as a possible solution to address this challenge. The discussed approach enables interaction techniques to be constructed as standalone dynamically deployable objects in ambient spaces during runtime