非合作航天器的立体视觉位姿测量

针对在轨服务中非合作航天器相对位姿测量的关键任务,提出了一种双目立体视觉方法。该方法利用两台大视场可见光相机获取高分辨率图像,用双边滤波方法对图像进行预处理,接着利用弧线段拟合法提取目标表面的对接环椭圆,用Hough变换法提取目标的矩形边框特征,并引入极线约束准则、对接环尺寸约束和光流跟踪的方法,提高算法的提取精度和效率。利用立体视觉构建非合作目标的对接环平面和边框角点,建立目标坐标系,解算与世界坐标系之间的位姿关系。暗室环境下的实验结果表明,双目相机系统逼近(12.0~2.0 m)实验中,相对位置精度优于1.0 cm,相对姿态精度优于0.41°;目标姿态转动实验中,相对位置精度优于1.3 cm,相对姿态精度优于0.88°,位姿解算精度较高,可以为追踪航天器提供连续的位姿导航信息。

Stereo measurement of position and attitude of non-cooperative spacecraft

For in-orbit servicing,a binocular stereo vision measurement method was proposed to precisely determine the relative position and attitude of non-cooperative spacecraft.First,two wide-field visible light cameras were used to capture high-resolution images;the images were then preprocessed via bilateral filtering.Next,the docking ring from the target surface was extracted using arc line segments.The rectan?gular border features of the target were extracted by Hough transform.Polar line constraints,the size constraint of the docking ring,and the optical flow method were introduced to improve the extraction accuracy and efficiency of the algorithm.The docking ring plane and the corner of the frame of the non-cooperative target were determined using stereo vision.Further,the target's coordinate system was established and its relative position was calculated using the world coordinate system.Accordingly,a binocular-camera sys?tem approximation(12.0-2.0 m)experiment performed in a dark room reveals that the accuracy of rela?tive position exceeds 1.0 cm,whereas that of relative attitude exceeds 0.41°;the relative position accura?cy exceeds 1.3 cm,whereas relative attitude accuracy exceeds 0.88°in the target attitude rotation experi?ment,which can provide continuous position and attitude navigation information for tracking spacecraft.