Visual system is an important part of autonomous unmanned system. The raindrops attached to the surface of the camera lens will produce artifacts in the image, resulting in the degradation of image quality, which will significantly affect the performance of the visual system. The detection and removal methods of attached raindrops in recent years were comprehensively and deeply researched. The essence of the problem was condensed, and the existing raindrop imaging models were summarized. Different technical methods were sorted out from three directions: model-based, data-driven and camera system-based, then the development of deep network model was summarized from two aspects of network architecture and loss function. The existing datasets of attached raindrops were summarized, and the performance of some algorithms was compared through the experimental results. The main problems in the task of raindrop detection and removal were discussed, and the possible development direction in this field was prospected.

To study the influence of dynamic characteristics of the arresting hook of carrier-based aircraft on arresting results, the rigid body dynamics model of the plane motion carrier-based aircraft was established. The rigid body dynamics model of the spatial motion arresting hook was established considering the effect of longitudinal cushioning of the arresting hook. Lagrange′s equation of first kind was employed to establish the revolute joint model of the carrier-based aircraft and the arresting hook, and then the dynamics models of the system consists of the carrier-based aircraft and its arresting hook were established. The models were united with dynamics model of arresting gear to form the complete blocking dynamic simulation model. The experiment of the arresting process of aircraft was carried out. The experiment results and simulation results of the arresting process were compared and analyzed. The results demonstrate the effectiveness and accuracy of the dynamics model of the carrier-based aircraft and arresting hook, and reveal the significant influence of characteristics of the arresting hook on arresting overload.