Dong F.,Instrumentation |
Ieng S.-H.,University Pierre and Marie Curie |
Savatier X.,Instrumentation |
Etienne-Cummings R.,University of Baltimore |
Benosman R.,University Pierre and Marie Curie
International Journal of Robotics Research | Year: 2013
Real-time vision-based navigation is a difficult task largely due to the limited optical properties of single cameras that are usually mounted on robots. Multiple camera systems such as polydioptric sensors provide more efficient and precise solutions for autonomous navigation. They are particularly suitable for motion estimation because they allow one to formulate a linear optimization. These sensors capture the visual information in a more complete form called the plenoptic function that encodes the spatial and temporal light radiance of the scene. The polydioptric sensors are rarely used in robotics because they are usually thought to increase the amount of data produced and require more computational power. This paper shows that these cameras provide more accurate estimation results in mobile robotics navigation if designed properly. It also shows that a plenoptic vision sensor with a resolution ranging from 3 × 3 to 40 × 30 pixels camera, provides higher accuracy than a mono-SLAM running on a 320 × 240 pixels camera. The paper also gives a complete scheme to design usable real-time plenoptic cameras for mobile robotics applications by establishing the link between velocity, resolution and motion estimation accuracy. Finally, experiments on a mobile robot are shown allowing for a comparison between optimal plenoptic visual sensors and single high-resolution cameras. The estimation with the plenoptic sensor is more accurate than a monocular high-definition camera with a processing time 100 times lower. © The Author(s) 2013.
Kasraoui M.,Instrumentation |
Cabani A.,Instrumentation |
International Journal of Distributed Sensor Networks | Year: 2015
IPv6 over Low Power Wireless Personal Area Networks (6LoWPANs), in the next generation of wireless sensor networks, represent an emerging field which can be integrated with Internet technology. Security is one of the most important issues in 6LoWPANs given the vulnerability to security threats from Internet and the inherent constraints such as bandwidth, processing power, memory, and energy. Despite limited resources, data security for nodes adds an additional heavy cost by using various security schemes. Moreover, there is no standard approach to provide the end-to-end security in 6LoWPANs. In this work, we first axed our research to propose a new end-to-end security scheme for IP enabled sensor networks to optimize battery energy consumption and then we adapted the Internet Key Exchange version 2 (IKEv2) to wireless sensor networks while taking into consideration the scarce resources. Hence a novel Cooperative Key Exchange System (CKES) has been proposed in this paper based on Chinese Remainder Theorem (CRT) which has also been implemented in NS2 to analyze energy consumption compared to IKEv2. © 2015 Mohamed Kasraoui et al.