1 中国科学院国家空间科学中心, 北京 100190
2 中国科学院大学 计算机科学与技术学院, 北京 100049
3 中国科学院大学 杭州高等研究院基础物理与数学科学学院, 杭州 310024
针对视觉同步定位与建图(SLAM)算法前端漂移误差累积问题, 提出基于光学成像模拟的视觉里程计方法。该方法利用稠密三维点云数据进行目标表面泊松重建及材质物理特性关联, 依据光学物理特性和光线追踪原理构建基于物理模型的成像渲染引擎(PBRT), 生成不同观测条件下的目标特性仿真图像; 将目标特性仿真图像与光学相机拍摄图像进行配准与运动偏差恢复, 并设计扩展卡尔曼滤波器(EKF)输出位姿状态最优估计值。通过原型系统研制与实验评估表明: 该方法有效克服了传统方法漂移误差累积的问题, 相较传统ORB-SLAM2算法前端定位精度提升了56%, 为视觉里程计的设计提供了一种新的技术思路。
光学成像模拟 光线追踪 位姿估计 视觉里程计 扩展卡尔曼滤波 optical imaging simulation ray tracing positional estimation visual odometry extended Kalman filter
1 中国科学院国家空间科学中心复杂航天系统电子信息技术重点实验室，北京 100190
2 中国科学院大学，北京 100049
3 中国科学院大学杭州高等研究院基础物理与数学科学学院，浙江 杭州 310024
星间超远距离传输仿真在精密激光测距任务中发挥着重要的作用。激光在星间的传输距离可达几百至百万公里量级，由于探测过程中的波前像差和衍射效应，无法直接采用经典高斯光束追迹的方法对其进行仿真。本文应用模式分解法对星间超远距离衍射传输进行仿真，通过与解析解和夫琅禾费衍射积分计算结果的对比分析以验证仿真精度，分析分解阶数、初始高斯光束腰半径与圆孔半径之比等参数对仿真精度的影响，从而为空间精密激光测距任务仿真提供一种兼顾计算精度和效率的数值模拟方法。
衍射与光栅 空间精密激光测距 衍射传输 模式分解法 超远距离 激光与光电子学进展
2022, 59(21): 2105002
Author Affiliations
Abstract
1 School for Information and Opto-Electronic Science and Engineering, South China Normal University, Guangzhou 510631
2 Department of Applied Physics, South China University of Technology, Guangzhou 510641
3 College of Applied Physics, Guangdong University of Technology, Guangzhou 510090
Dark-current-voltage curves and photon-current-voltage curves were measured by a passive quenched circuit so that the voltage applied to the avalanche photodiode can be much higher than breakdown voltage in study on the depth of punch through. The photo-current-voltage curve indicated clearly the punch-through voltage while the dark current-voltage curve is insensitive to the punch through. Furthermore, the avalanches initiated by the photo-generated carrier at a voltage lower than that from the thermo-generated carriers and explained based on the different distribution of the carriers.
040.5570 Quantum detectors 040.3060 Infrared 040.3780 Low light level 040.5160 Photodetectors 230.5170 Photodiodes 270.5290 Photon statistics Chinese Optics Letters
2005, 3(0s): 62
Author Affiliations
Abstract
1 School for Information and Opto-Electronic Science and Engineering, South China Normal University, Guangzhou 510631
2 Department of Applied Physics, South China University of Technology, Guangzhou,510641
3 College of Applied Physics, Guangdong University of Technolody, Guangzhou 510090
The passively quenched operation of avalanche photodiode (APD) has been used to characterizing InGaAs/InP APD including punch through voltage, avalanche voltage and break down voltage that are all important in the design of APD for single photon detection. The punch through voltage at certain doping level can be related to the thickness of the InP multiplication layer and the thickness of the un-intentionally doped n-type InP layer can be adjusted in according to the experimental data. The analysis indicates that the punch through voltage should be close to the breakdown voltage that can be realized by adjusting the thickness of InP multiplication layer.
040.3060 Infrared 040.3780 Low light level 040.5570 Quantum detectors 160.1890 Detector materials 230.5160 Photodetectors 270.5570 Quantum detectors Chinese Optics Letters
2005, 3(0s): 31
