Computer Vision on Mars

Increasing the level of spacecraft autonomy is essential for broadening the reach of solar system exploration. Computer vision has and will continue to play an important role in increasing autonomy of both spacecraft and Earth-based robotic vehicles. This article addresses progress on computer vision for planetary rovers and landers and has four main parts. First, we review major milestones in the development of computer vision for robotic vehicles over the last four decades. Since research on applications for Earth and space has often been closely intertwined, the review includes elements of both. Second, we summarize the design and performance of computer vision algorithms used on Mars in the NASA/JPL Mars Exploration Rover (MER) mission, which was a major step forward in the use of computer vision in space. These algorithms did stereo vision and visual odometry for rover navigation and feature tracking for horizontal velocity estimation for the landers. Third, we summarize ongoing research to improve vision systems for planetary rovers, which includes various aspects of noise reduction, FPGA implementation, and vision-based slip perception. Finally, we briefly survey other opportunities for computer vision to impact rovers, landers, and orbiters in future solar system exploration missions.     

基于立体视觉的移动机器人导航算法

移动机器人立体视觉系统不仅提供三维地形图用于障碍规避和路径规划,其结果还可以用于视觉导航。以移动机器人立体视觉系统为基础,研究了基于前后两个位置上立体图对的视觉测量算法用于移动机器人的连续导航,讨论了影响导航精度的因素和改进方法;研究了基于局部和全局三维地形图的地形匹配算法用于定期校正位置误差,算法实现简便,定位精度取决于地形图精度。实验结果证明了两种方法的有效性,可以兼顾近距离和中远距离导航任务。     

动态环境下基于旋转-平移解耦的立体视觉里程计算法

在实际应用中,若图像中的动态特征数量多且运动方向一致,这些特征会对视觉里程计的估计结果产生严重的影响.本文针对这类问题提出一种根据图像特征点位置解耦估计摄像机旋转-平移的立体视觉里程计算法.算法通过立体视觉系统将特征点划分成"远点"和"近点".在随机抽样一致性算法(RANSAC)框架下,采用"远点"估计视觉系统的姿态;进而在姿态已知的条件下,通过"近点"估计摄像机平移,实现旋转-平移解耦计算.这样处理可以通过姿态约束减少近距离运动物体对视觉里程计的影响.实验表明,在实际道路环境中,本文基于旋转-平移解耦估计的算法较之传统的同时估计旋转-平移的算法,能有效剔除动态特征.所提出算法对动态特征的抗干扰能力更好,鲁棒性更强,精度更高.     

面向星球探测的岩石三维表面评估技术

针对星球探测任务中的岩石采样问题,利用双目立体视觉装置采集不同岩石图像,采用立体视觉算法获得岩石表面的三维点云数据。以三角剖分后生成的三角片法向量夹角为基本元素,提出基于C均值聚类的岩石表面评估算法,对岩石平整三维表面进行评估计算,并用不同颜色加以区分。仿真结果证明了该算法的有效性。     

基于视觉的遥操作机器人精密装配系统

针对遥操作精密装配问题,基于视觉伺服,并通过图形图像叠加等方法,加入了有效的人工辅助措施,很好地利用了人类智能,增强了精密作业系统的鲁棒性和可实现性,并最终实现了遥操作精密装配．     

Robots in Space: U.S. Missions and Technology Requirements into the Next Century

The Telerobotics Program of the National Aeronautics and Space Administration (NASA) Office of Space Science is developing innovative telerobotics technologies to enable or support a wide range of space missions over the next decade and beyond. These technologies fall into four core application areas: landers, surface vehicles (rovers), and aerovehicles for solar system exploration and science; rovers for commercially supported lunar activities; free-flying and platform-attached robots for in-orbit servicing and assembly; and robots supporting in-orbit biotechnology and microgravity experiments. Such advanced robots will enable missions to explore Mars, Venus, and Saturn's moon Titan, as well as probes to sample comets and asteroids. They may also play an important role in commercially funded exploration of large regions on Earth's Moon, as well as the eventual development of a human-supporting Lunar Outpost. In addition, in-orbit servicing of satellites and maintenance of large platforms like the International Space Station will require extensive robotics capabilities.     

Outdoor Visual Position Estimation for Planetary Rovers

This paper describes (1) a novel, effective algorithm for outdoor visual position estimation; (2) the implementation of this algorithm in the Viper system; and (3) the extensive tests that have demonstrated the superior accuracy and speed of the algorithm. The Viper system (Visual Position Estimator for Rovers) is geared towards robotic space missions, and the central purpose of the system is to increase the situational awareness of a rover operator by presenting accurate position estimates. The system has been extensively tested with terrestrial and lunar imagery, in terrains ranging from moderate—the rounded hills of Pittsburgh and the high deserts of Chile—to rugged—the dramatic relief of the Apollo 17 landing site—to extreme—the jagged peaks of the Rockies. Results have consistently demonstrated that the visual estimation algorithm estimates position with an accuracy and reliability that greatly surpass previous work.     

双目视觉的匹配算法综述

双目视觉是获取对现实世界立体感知的重要方法,在自动驾驶等领域得到了普遍的应用。立体匹配是实现双目感知的前提,该算法对左右摄像机拍摄的照片进行像素级的匹配,生成稠密视差图,从而获取了三维坐标信息。概述了立体匹配算法近 20 年来的发展过程,围绕基于人工特征和深度学习两个方向进行了综述,对算法实现过程中的代价计算、代价聚合、视差计算和视差求精进行分析讨论,评估了算法的准确性和时间复杂度。最后总结了立体匹配算法面对的挑战和对未来发展的展望。     

月球车巡视探测的双目视觉里程算法与实验研究

月球车在月面巡视的移动距离测量是实现安全有效探测的重要保障.基于视觉里程计的定位方法是解决月面滑移,提高行驶里程推算精度的有效方法,对月球车实现高精度定位具有重要意义.本文对双目视觉里程算法的设计及实现技术进行了深入研究,并对基于不同特征提取算法的视觉里程定位方法进行了实验验证,通过与高精度全站仪数据比较,验证了算法的测量精度和有效性.     

考虑多位姿估计约束的双目视觉里程计

为了提升复杂环境中双目视觉里程计的精度,提出一种考虑多位姿估计约束的双目视觉里程计方法.首先,分别建立匹配深度已知点与深度未知点的数学模型,将深度未知点引入2D-2D位姿估计模型,从而充分利用图像信息;然后,基于关键帧地图点改进3D-2D位姿估计模型,并结合当前帧地图点更新关键帧地图点,从而增加匹配点对数,提高位姿估计精度;最后,根据改进的2D-2D及3D-2D位姿估计模型,建立多位姿估计约束位姿估计模型,结合局部光束平差法对位姿估计进行局部优化,达到定位精度高且累积误差小的效果.数据集实验和实际场景在线实验表明,所提出方法满足实时定位要求,且有效地提高了自主定位精度.     

Scanning electron microscope-based stereo analysis

In this paper we present a novel technique to analyze stereo images generated from a SEM. The two main features of this technique are that it uses a binary linear programming approach to set up and solve the correspondence problem and that it uses constraints based on the physics of SEM image formation. Binary linear programming is a powerful tool with which to tackle constrained optimization problems, especially in cases that involve matching between one data set and another. We have also analyzed the process of SEM image formation, and present constraints that are useful in solving the stereo correspondence problem. This technique has been tested on many images. Results for a few wafers are included here.