Study On Attitude Auto-Interpretation Of Moving Object In Highspeed Video

A digital high speed video camera system is utilized by an ordnance test center tomeasure attitude of various kinds of missiles or UAVs (Unmanned Aerial Vehicle).Attitude parameters comprise 3D attitude and substation attitude. 3D attitude refers tothe pitch and yaw angles of the axis, with a measure error of no more than 1o. Andsubstation attitude is the line equation of axis in the monocular highspeed video shotfrom substation. The error of the slope is no more than 0.5o and that of the interceptdoes not exceed 0.5 pixel. The intention of our research is to develop a post-flight data processing softwarethat can auto-interpret the substation attitude and compute the 3D attitude accordingto its substation attitude by "axis joint method". The major innovations of this dissertation are as follows: 1. The auto-interpretation of substation attitude is mapped to a framework of theestimation of 2D motion parameters. The intuition behind this idea is that if themotion parameters of a target are computed by the method of motion analysis and theline equation of axis in the first frame is known, the substation attitude in thosesequential frames can be estimated. 2. A robust motion estimation method based on corner tracking is proposed. AKalman-based KLT corner tracker is proposed to match the corners on a targetbetween neighboring frames. A robust estimator, RANSAC is utilized to exclude falsecorrespondences. And according to those correct correspondences, systems of linearequation are constructed and solved by the method of least squares. 3. A Condensation-based motion estimation method is proposed. In theframework of Condensation, motion parameters are taken as the measure vector,while the state vector is composed of current time motion parameters and those of lasttime. Linear system equation and linear measure equation that describe the attackingUAV are modeled. Post density of the state vector is evaluated by shape similaritybetween the contour model and edge points, and distance transformation is introducedto improve calculation efficiency. 4. A motion estimation method based on "Condensation+DE (DifferentialEvolution)" is proposed. The parameter distribution space of Condensation is taken asthe search space of contour registration, while DE is utilized as the global optimizer.From the other view, the estimation of posterior density in Condensation can beregarded as the problem of global optimization solved by DE. With the importation ofglobal optimization, degeneracy problem of Condensation is avoided, demand isreduced on accuracy of system model, and estimation of motion parameters is morerobust and accurate.As a result of our research, the attitude auto-interpretation software has beentested and accepted by the ordnance test center.