信息通信技术(information and communications technology,ICT)等的发展使现代地图面临着机遇和挑战:地图趋向数字虚拟空间方向发展,地图学的研究方法、主题与传统地图学大相径庭,地图虚拟空间的理论还有很大的发展空间,同时互联网技术...信息通信技术(information and communications technology,ICT)等的发展使现代地图面临着机遇和挑战:地图趋向数字虚拟空间方向发展,地图学的研究方法、主题与传统地图学大相径庭,地图虚拟空间的理论还有很大的发展空间,同时互联网技术(internet technology,IT)领域的学科跨界迫使地图逐渐发展成为互联网产品的附属物,内忧外患的双重夹击使得地图学亟待完善和更新理论。地图学发展的难题促使学者向其他领域进行探索。计算机游戏通常具有明显的地理意义,"数字+文化"的发展将游戏推向高新技术的前列,游戏地图则是现代ICT技术和地图的合体。以游戏地图的结构为研究对象,以游戏地图的维度、交互性、叙事探索性和文化传播性来探究虚拟空间的特点、本质及对现实物理世界的启示,发掘其对地图理论的扩展,从而完善ICT时代地图学的知识和理论,促进地图学的发展。展开更多
This paper proposes a new Zernike modal gray map reconstruction algorithm used in the nematic liquid crystal adaptive optics system. Firstly, the new modal algorithm is described. Secondly, a single loop correction ex...This paper proposes a new Zernike modal gray map reconstruction algorithm used in the nematic liquid crystal adaptive optics system. Firstly, the new modal algorithm is described. Secondly, a single loop correction experiment was conducted, and it showed that the modal method has a higher precision in gray map reconstruction than the widely used slope method. Finally, the contrast close-loop correction experiment was conducted to correct static aberration in the laboratory. The experimental results showed that the average peak to valley （PV） and root mean square （RMS） of the wavefront corrected by mode method were reduced from 2.501A （λ= 633 nm） and 0.610A to 0.0334λ and 0.00845A, respectively. The corrected PV and RMS were much smaller than those of 0.173A and 0.048A by slope method. The Strehl ratio and modulation transfer function of the system corrected by mode method were much closer to diffraction limit than with slope method. These results indicate that the mode method can take good advantage of the large number of pixels of the liquid crystal corrector to realize high correction precision.展开更多
针对同步定位与建图(Simultaneous Localization and Mapping,SLAM)系统经常因为相机抖动及场景结构单一等问题而导致跟踪失败的情况,以及重建三维地图的任务,提出了一种混合SLAM方法(R-ORB SLAM)。该方法采用一种基于光度误差的位姿粗...针对同步定位与建图(Simultaneous Localization and Mapping,SLAM)系统经常因为相机抖动及场景结构单一等问题而导致跟踪失败的情况,以及重建三维地图的任务,提出了一种混合SLAM方法(R-ORB SLAM)。该方法采用一种基于光度误差的位姿粗略估计作为特征视觉里程计的先验,在ORB-SLAM2跟踪失败的情况下,使用该结果参与位姿估计。同时,在建图模块,对由每个关键帧点云拼接得到的全局点云地图使用VoxelGrid滤波器进行下采样,得到去除冗余点的稠密三维点云地图。通过对三维点云地图使用Poisson算法实现表面重建,得到三维地图模型。在两个流行的公开数据集上的实验结果表明,本文方法能有效解决跟踪失败问题,实现三维地图重建,具有较高的跟踪精度与重建精度。展开更多
文摘信息通信技术(information and communications technology,ICT)等的发展使现代地图面临着机遇和挑战:地图趋向数字虚拟空间方向发展,地图学的研究方法、主题与传统地图学大相径庭,地图虚拟空间的理论还有很大的发展空间,同时互联网技术(internet technology,IT)领域的学科跨界迫使地图逐渐发展成为互联网产品的附属物,内忧外患的双重夹击使得地图学亟待完善和更新理论。地图学发展的难题促使学者向其他领域进行探索。计算机游戏通常具有明显的地理意义,"数字+文化"的发展将游戏推向高新技术的前列,游戏地图则是现代ICT技术和地图的合体。以游戏地图的结构为研究对象,以游戏地图的维度、交互性、叙事探索性和文化传播性来探究虚拟空间的特点、本质及对现实物理世界的启示,发掘其对地图理论的扩展,从而完善ICT时代地图学的知识和理论,促进地图学的发展。
基金Project supported by the National Natural Science Foundation of China (Grants Nos.60736042,60578035 and 50703039)Science and Technology Cooperation Project between Chinese Academy of Sciences and Jilin Province (Grant No.2008SYHZ0005)
文摘This paper proposes a new Zernike modal gray map reconstruction algorithm used in the nematic liquid crystal adaptive optics system. Firstly, the new modal algorithm is described. Secondly, a single loop correction experiment was conducted, and it showed that the modal method has a higher precision in gray map reconstruction than the widely used slope method. Finally, the contrast close-loop correction experiment was conducted to correct static aberration in the laboratory. The experimental results showed that the average peak to valley （PV） and root mean square （RMS） of the wavefront corrected by mode method were reduced from 2.501A （λ= 633 nm） and 0.610A to 0.0334λ and 0.00845A, respectively. The corrected PV and RMS were much smaller than those of 0.173A and 0.048A by slope method. The Strehl ratio and modulation transfer function of the system corrected by mode method were much closer to diffraction limit than with slope method. These results indicate that the mode method can take good advantage of the large number of pixels of the liquid crystal corrector to realize high correction precision.
文摘针对同步定位与建图(Simultaneous Localization and Mapping,SLAM)系统经常因为相机抖动及场景结构单一等问题而导致跟踪失败的情况,以及重建三维地图的任务,提出了一种混合SLAM方法(R-ORB SLAM)。该方法采用一种基于光度误差的位姿粗略估计作为特征视觉里程计的先验,在ORB-SLAM2跟踪失败的情况下,使用该结果参与位姿估计。同时,在建图模块,对由每个关键帧点云拼接得到的全局点云地图使用VoxelGrid滤波器进行下采样,得到去除冗余点的稠密三维点云地图。通过对三维点云地图使用Poisson算法实现表面重建,得到三维地图模型。在两个流行的公开数据集上的实验结果表明,本文方法能有效解决跟踪失败问题,实现三维地图重建,具有较高的跟踪精度与重建精度。
