大型外挂物投放影像测量亚像素定位技术

Sub Pixel Positioning Technology for Large External Store Image Measurement

武器投放特别是大型外挂物投放时的初始姿态对武器的命中精度和飞机飞行安全具有重要影响。在某型飞机武器火控试飞中,需要完成某型导弹发射初始段姿态测量。由于该型导弹弹体大,测量视场分辨率低。为提高测量精度,采用亚像素定位技术,利用Hough变换提取相交直线,以直线元素为基准,提出以垂直于原图像直线方向的窗口,计算每个像素梯度的模,选取对应的坐标数据带入线性误差方程,用最小二乘法解其改正数,迭代求解精确求得直线参数,解算交点实现测量特征点图像坐标的亚像素定位。试验结果表明,经过亚像素定位后,测量精度可以提高约三倍,满足测量要求。

The initial pose of the weapon delivery,especially the large external store,has important influence on the hit preci-sion of weapon and the safety of aircraft flight. In a certain type of aircraft weapon fire control test,it needs to complete a certain type of missile launch initial segment attitude measurement. Because the missile body is large,the measurement field of resolution is low. In order to improve the measurement accuracy,the sub pixel positioning technology is adopted. Using Hough transform to de-tect straight line. Based on the linear elements,a window which is perpendicular to the direction of the line of the original image is proposed. Each pixel gradient mode is calculated,and the coordinate data generation is selected into the linear error equation. Square method is used to solve the correction data,and the iterative method to obtain the accurate linear parameters. The sub pixel location of the image coordinates of the measured feature points is realized by calculating the intersection point. The experiment re-sults show that after sub pixel location,measurement accuracy can be improved about three times,meeting the measurement re-quirement.