Research On Monocular Vision Localization Algorithm Of Light Rotor UAV Based On Improved ORB

Light rotor UAV is not suitable for positioning with large or heavy equipment,such as laser.GPS positioning accuracy is insufficient,and differential GPS cost is too high.However,monocular positioning is very suitable for light rotor UAV.Aiming at the precise positioning requirements of light rotorcraft UAV,a series of research works based on monocular vision positioning algorithm have been carried out.On the basis of introducing each link and process of monocular vision positioning algorithm and analyzing the key practices and significance.Aiming at the problem that ORB feature point matching effect is reduced due to illumination change,an improved illumination homogenization algorithm is proposed.The algorithm selects the affected feature points and uses deformed histogram homogenization to change the distribution of pixel value in the pixel block where the feature points are located.To solve the problem that ORB feature point matching effect is still low,BEBLID descriptor extraction algorithm is used to improve the ORB feature extraction process,and the effectiveness and excellence of the new method are verified by experiments.By analyzing the processing flow of IMU information,an improved tight coupling optimization scheme of GPS and visual inertial navigation system is proposed,which enables the GPS information to optimize the position and pose information of the image frame at the previous time and the next time simultaneously,so that the latest image frame can also be optimized.The error source and coordinate transformation of GPS are analyzed,and the initialization scheme of the necessary parameters is proposed when GPS participates in the tight coupling optimization.By adding the optimization of the necessary parameters of GPS in the joint initialization of the visual inertial navigation system,these necessary parameters can be calculated online.Finally,the data from Euroc dataset and the data collected by the UAV platform are used to conduct experiments.The experimental results verify the effectiveness of the proposed algorithm.In general,the proposed monocular vision positioning algorithm integrating IMU information and GPS information has excellent positioning effect,which is suitable for the precise positioning requirements of light rotor UAV,and provides certain theoretical and practical value for the precise positioning of light rotor UAV.