Road obstacles cause serious accidents that have a severe impact on driver safety, traffic flow efficiency and damage of the vehicle. Detecting obstacles are important to prevent or to reduce such kind of the accidents and fatalities. However, it is difficult and becomes tricky because of some problems like presence of shadow, environmental changes or a sudden action of any moving things (e.g., car overtaking, animal coming) and many more. Thereby, this paper aims to design an obstacle detection technique based on (i) moving cameras and (ii) moving objects. These methods are applied to obstacle detection phase, in order to identify the different obstacles (e.g., potholes, animals, stop sign, obstacles, bumps, road cracks) by considering road dimensions. A new technique is introduced for detecting obstacles from moving camera and moving objects which overcomes several limitations over stationary cameras and moving/stationary objects. Further, paper reviews recent research trends to detect obstacles for moving cameras and moving objects with discussion of key points and limitations of each approach. Finally, the results show that the proposed method is more robust and reliable than the previous approaches based on the stationary cameras.

One of the important issues related to MANETs is the security. Grayhole attack is one of the most prominent attacks on the network layer of MANET which tends to degrade the network performance by performing selective packet dropping. In this paper, we propose a security mechanism that tends to mitigate the Grayhole attack during the route discovery time as well as during data transmission time. We modify AODV protocol such that it can avoid Grayhole attacker node from participating in the data transmission route, and if the attacker node somehow enters the route, it can be detected through the promiscuous mode monitoring.