针对合作靶标特征点成像在大跨度动态测量中的特征提取精度下降、实时性不足问题,提出了一种融合帧间运动预测与改进亚像素边缘检测的自适应光斑质心提取方法。基于合作靶标测量运动连贯性特性,构建了动态感兴趣区域(Region of Interest...针对合作靶标特征点成像在大跨度动态测量中的特征提取精度下降、实时性不足问题,提出了一种融合帧间运动预测与改进亚像素边缘检测的自适应光斑质心提取方法。基于合作靶标测量运动连贯性特性,构建了动态感兴趣区域(Region of Interest,ROI)特征参数模型,以帧间运动预测实现ROI的快速定位,结合大律法阈值优化策略实现自适应Canny边缘检测,在提升计算效率的同时有效解决了不同测量距离下的降噪问题。然后,采用多方向Sobel算子与强度斜坡改进的Zernike矩相结合改进了边缘点定位算法,并基于高斯牛顿迭代改进鲁棒最小二乘圆拟合法,实现质心坐标计算。实验结果表明:在仿真测试中,本方法在不同噪声水平下的质心定位误差为0.001~0.025像素;实际测试中,ROI预测算法可满足加速度8.75 m/s^(2)以内的测量场景需求,10~30 m测量距离内的光斑重复性定位误差稳定在0.016~0.040像素,优于传统方法;光斑提取速度提升约75.5%,显著增强了系统的实时处理能力。本研究可为合作靶标的测量应用提供有效技术保障。展开更多
Visual navigation is imperative for successful asteroid exploration missions.In this study,an integrated visual navigation system was proposed based on angles-only measurements to robustly and accurately determine the...Visual navigation is imperative for successful asteroid exploration missions.In this study,an integrated visual navigation system was proposed based on angles-only measurements to robustly and accurately determine the pose of the lander during the final landing phase.The system used the lander's global pose information provided by an orbiter,which was deployed in space in advance,and its relative motion information in adjacent images to jointly estimate its optimal state.First,the landmarks on the asteroid surface and markers on the lander were identified from the images acquired by the orbiter.Subsequently,an angles-only measurement model concerning the landmarks and markers was constructed to estimate the orbiter's position and lander's pose.Subsequently,a method based on the epipolar constraint was proposed to estimate the lander's inter-frame motion.Then,the absolute pose and relative motion of the lander were fused using an extended Kalman filter.Additionally,the observability criterion and covariance of the state error were provided.Finally,synthetic image sequences were generated to validate the proposed navigation system,and numerical results demonstrated its advance in terms of robustness and accuracy.展开更多
文摘针对合作靶标特征点成像在大跨度动态测量中的特征提取精度下降、实时性不足问题,提出了一种融合帧间运动预测与改进亚像素边缘检测的自适应光斑质心提取方法。基于合作靶标测量运动连贯性特性,构建了动态感兴趣区域(Region of Interest,ROI)特征参数模型,以帧间运动预测实现ROI的快速定位,结合大律法阈值优化策略实现自适应Canny边缘检测,在提升计算效率的同时有效解决了不同测量距离下的降噪问题。然后,采用多方向Sobel算子与强度斜坡改进的Zernike矩相结合改进了边缘点定位算法,并基于高斯牛顿迭代改进鲁棒最小二乘圆拟合法,实现质心坐标计算。实验结果表明:在仿真测试中,本方法在不同噪声水平下的质心定位误差为0.001~0.025像素;实际测试中,ROI预测算法可满足加速度8.75 m/s^(2)以内的测量场景需求,10~30 m测量距离内的光斑重复性定位误差稳定在0.016~0.040像素,优于传统方法;光斑提取速度提升约75.5%,显著增强了系统的实时处理能力。本研究可为合作靶标的测量应用提供有效技术保障。
基金supported by the National Natural Science Foundation of China(Grant Nos.61673057 and 61803028)。
文摘Visual navigation is imperative for successful asteroid exploration missions.In this study,an integrated visual navigation system was proposed based on angles-only measurements to robustly and accurately determine the pose of the lander during the final landing phase.The system used the lander's global pose information provided by an orbiter,which was deployed in space in advance,and its relative motion information in adjacent images to jointly estimate its optimal state.First,the landmarks on the asteroid surface and markers on the lander were identified from the images acquired by the orbiter.Subsequently,an angles-only measurement model concerning the landmarks and markers was constructed to estimate the orbiter's position and lander's pose.Subsequently,a method based on the epipolar constraint was proposed to estimate the lander's inter-frame motion.Then,the absolute pose and relative motion of the lander were fused using an extended Kalman filter.Additionally,the observability criterion and covariance of the state error were provided.Finally,synthetic image sequences were generated to validate the proposed navigation system,and numerical results demonstrated its advance in terms of robustness and accuracy.
