Determining the position of obstacles is crucial for unmanned vehicles, and, to achieve this, cameras and radar sensors are widely utilized. However, establishing correlation between two or more sensors proves challenging in the dynamically changing maritime environment. To solve these issues, we propose the AnytimeFusion algorithm. The key innovation of AnytimeFusion lies in the utilization of a parameter-free method that does not require accurate sensor alignment and calibration. The algorithm consists of the following four stages. First, calibration targets are selected in the maritime environment based on segmentation images. Second, radar and camera data are pre-fused to model the correlation of azimuth information. After completing the auto-calibration stages, Inverse Perspective Mapping (IPM) is employed to integrate the coordinate systems of the two sensors. To determine the parameters for this integration, optimization based on the Particle Swarm Optimization (PSO) method is employed. Finally, an Error Polygon for the positions of the camera and radar is generated, and sensor fusion is carried out based on this information. We validated our method through experiments conducted on real ships in complex maritime environments, achieving an average accuracy of 95.7%.

Recent advances in 3D depth sensors have created many opportunities for security, surveillance, and entertainment. The 3D depth sensors provide more powerful monitoring systems for dangerous situations irrespective of lighting conditions in buildings or production facilities. To robustly recognize emergency actions or hazardous situations of workers at a production facility, we present human joint estimation and behavior recognition algorithms that solely use depth information in this paper. To estimate human joints on a low cost computing platform, we propose a human joint estimation algorithm that integrates a geodesic graph and a support vector machine (SVM). The human feature points are extracted within a range of geodesic distance from a geodesic graph. The geodesic graph is used for optimizing the estimation result. The SVM-based human joint estimator uses randomly selected human features to reduce computation. Body parts that typically involve many motions are then estimated by the geodesic distance value. The proposed algorithm can work for any human without calibration, and thus the system can be used with any subject immediately even with a low cost computing platform. In the case of the behavior recognition algorithm, the algorithm should have a simple behavior registration process, and it also should be robust to environmental changes. To meet these goals, we propose a template matching-based behavior recognition algorithm. Our method creates a behavior template set that consists of weighted human joint data with scale and rotation invariant properties . A single behavior template consists of the joint information that is estimated per frame. Additionally, we propose adaptive template rejection and a sliding window filter to prevent misrecognition between similar behaviors. The human joint estimation and behavior recognition algorithms are evaluated individually through several experiments and the performance is proven through a comparison with other algorithms. The experimental results show that our method performs well and is applicable in real environments.

In this paper, a novel cooperative coevolution (CC)-based model predictive control (MPC) is proposed to deal with formation control problem. While conventional evolutionary algorithm (EA)-based MPC approaches cannot guarantee the stability, the proposed CC-based MPC guarantees the asymptotic stability regardless of the optimality of the solution that the CC-based algorithm generates with a small number of individuals. To guarantee the stability, a terminal state constraint is found, and then a repair algorithm is applied to all candidate solutions to meet the constraint. The cooperatively coevolving particle swarm optimization (CCPSO), most recently developed algorithm among CC-based EAs, is adopted and modified to fit into the formation control problem. Experiments are performed on a group of nonholonomic mobile robots to demonstrate the effectiveness of the CC-based MPC.

Many studies have been conducted to achieve natural interaction between robots and humans, and this area of research is becoming more important. Except for several works, however, most gesture recognition algorithms are designed with an assumption that the sensor does not move. To resolve this problem, we propose an algorithm that can robustly recognize gestures while the sensor is moving.

Most path planning algorithms for a marine surface vehicle in the ocean environment have been developed only for a 2-D (x;y) plane without considering the vehicle heading angle. As a result, the vehicle has a difficulty in following the path correctly. In this paper, we propose a limit-cycle circle set that applies to the Theta* algorithm. The minimum turning radius of a marine surface vehicle is calculated using a limit-cycle circle set, and circles of this radius is used to generate a configuration space of an occupancy grid map. After applying Theta* to this configuration space, the limit-cycle circle set is also applied to the start and end nodes to find the appropriate path with specified heading angles. The benefit of this algorithm is its fast computation time compared to other 3-D (x;y;θ) path planning algorithms, along with the fact that it can be applied to the 3-D kinematic state of the vehicle. We simulate the proposed algorithm and compare it with 3-D A* and 3-D A* with post smoothing algorithms.