Distance measurement and optimization methods for projectile and target using monocular vision

To solve the problem of measuring the distance between the projectile and the target, a method using monocular vision system for conventional ammunitions to measure the distance is proposed. According to the principle of projection imaging, the mapping relation of the three-dimensional (3-D) position and the 2-D image of the target is derived. The monocular vision measurement mathematical model is established by analyzing the coordinate transformation matrix of the projectile, camera and the reference frame. The affecting factors on the distance measurement accuracy are analyzed. The sequential quadratic programming (SQP) algorithm is used to optimize the focal length of the camera. The nonlinear filter based on linear parameter-varying (LPV) method is adopted to optimize the measurement results. The Semi-physical Simulation measurement experiment is designed on the three-axis turntable. The results show that the monocular vision measurement method can provide the comparatively accurate distance information and the error can be controlled within ±2% by using the LPV optimization method which improves the measurement accurate significantly. Then the feasibility of the measurement method and validity of the optimization method are verified.