Research Of Flying Object Nutation Angle Test Based On Linear CCD Image Analysis

Flying objects'posture is an important subject in theoretical research of flying, and nutation angle is one of the main research issues. The status of nutation angel's diversification is a direct factor for judging the stability of the flying object. Therefore, the test of nutation angle is of great significance. The research here focuses on the key technological issues of image analysis and engineering data processing in nutation angle test based on image acquisition by linear CCD.Due to the high speed of the flying objects, a method of using high rate linear CCD intersection to measure nutation angles of two orthogonal directions is proposed, and the space nutation angel is achieved through the measurement. The method of getting nutation data from image and testing system is studied, and technological steps for calculating nutation angle are identified:image's collection, target's separation, center coordinate's calculation of every line and axis fitting. The principle of linear CCD image collection and characteristics of image are studied; background and target are separated by substation; threshold is obtained by OSTU; target's coordinate is got by reading pixel value line by line; center coordinate of every line is calculated by average method and is fit into axis by least squares method; and nutation angle is calculated after scale corresponds.The calculation formula is also derived from the research and analysis of testing principle. The problem on the relation between the flying direction and nutation direction is resolved in engineering testing method of nutation angel based on CCD image analysis, and reliable nutation angel data are acquired. Moreover, research on acquisition method of the key parameters in calculation formula is made, and the effect on testing precision is analyzed.Image analysis and processing algorithms are verified by MATLAB7.1. The test of nutation angle is achieved by VC++6.0 with the help of OPENCV1.0 library. At the same time, a dynamic link library is created, and a visual interface software is developed by the MFC of VC++6.0. The actual gas cartridges nutation angle is measured in laboratory by linear CCD (Dalsa-P2-04k40) produced from DALSA Company with frame rate 68000. After theoretical analysis, the total nutation angle error is 4%.The test result shows that the nutation angel's testing method is feasible and the data is reliable.