在传统的块级持续数据保护(continuous data protection,CDP)系统中,过去某时间点的恢复任务一旦完成,被保护磁盘当前时刻的数据状态就被完全覆盖,必须将被保护磁盘再次恢复到最新数据状态,当前工作才能得以继续进行下去.针对传统CDP系...在传统的块级持续数据保护(continuous data protection,CDP)系统中,过去某时间点的恢复任务一旦完成,被保护磁盘当前时刻的数据状态就被完全覆盖,必须将被保护磁盘再次恢复到最新数据状态,当前工作才能得以继续进行下去.针对传统CDP系统恢复功能"一次查看,两次恢复"的问题,提出了日志盘分区技术及一种元数据层次式多级索引技术.将元数据与变动数据分别存放在日志盘的不同区域,并利用B^+树与改进B^+树将元数据区块和变动数据区块组织起来,形成元数据层次式多级索引,将过去任意时间点的数据挂载到虚拟磁盘供用户检视.经实验证明,该方法在不影响被保护磁盘当前数据状态的前提下向用户提供过去任意时间点的数据,简化了用户操作,减少了时间消耗.展开更多
Camera calibration is critical in computer vision measurement system, affecting the accuracy of the whole system. Many camera calibration methods have been proposed, but they cannot consider precision and operation co...Camera calibration is critical in computer vision measurement system, affecting the accuracy of the whole system. Many camera calibration methods have been proposed, but they cannot consider precision and operation complexity at the same time. In this paper, a new technique is proposed to calibrate camera. Firstly, the global calibration method is described in de-tail. It requires the camera to observe a checkerboard pattern shown at a few different orientations. The checkerboard corners are obtained by Harris algorithm. With direct linear transformation and non-linear optimal algorithm, the global calibration pa-rameters are obtained. Then, a sub-regional method is proposed. Those corners are divided into two groups, middle corners and edge corners, which are used to calibrate the corresponding area to get two sets of calibration parameters. Finally, some experimental images are used to test the proposed method. Experimental results demonstrate that the average projection error of sub-region method is decreased at least 16% compared with the global calibration method. The proposed technique is simple and accurate. It is suitable for the industrial computer vision measurement.展开更多
文摘本文主要介绍如何利用 OS/2第一、二张安装盘来制作单盘简体中文版的 OS/2分区盘,该分区盘可支持4.3GB 以上的大硬盘分区,而原来的 OS/2安装盘则不支持。同时介绍如何利用该分区盘将硬盘分成两个甚至三个 C 盘,并分别采用16位文件分配表来安装 DOS 操作系统和32位文件分配表来安装 WINDOWS98操作系统。
文摘在传统的块级持续数据保护(continuous data protection,CDP)系统中,过去某时间点的恢复任务一旦完成,被保护磁盘当前时刻的数据状态就被完全覆盖,必须将被保护磁盘再次恢复到最新数据状态,当前工作才能得以继续进行下去.针对传统CDP系统恢复功能"一次查看,两次恢复"的问题,提出了日志盘分区技术及一种元数据层次式多级索引技术.将元数据与变动数据分别存放在日志盘的不同区域,并利用B^+树与改进B^+树将元数据区块和变动数据区块组织起来,形成元数据层次式多级索引,将过去任意时间点的数据挂载到虚拟磁盘供用户检视.经实验证明,该方法在不影响被保护磁盘当前数据状态的前提下向用户提供过去任意时间点的数据,简化了用户操作,减少了时间消耗.
基金Tianjin Research Program of Application Foundation and Advanced Technology(No.14JCYBJC18600,No.14JCZDJC39700)the National Key Scientific Instrument and Equipment Development Project(No.2013YQ17053903)
文摘Camera calibration is critical in computer vision measurement system, affecting the accuracy of the whole system. Many camera calibration methods have been proposed, but they cannot consider precision and operation complexity at the same time. In this paper, a new technique is proposed to calibrate camera. Firstly, the global calibration method is described in de-tail. It requires the camera to observe a checkerboard pattern shown at a few different orientations. The checkerboard corners are obtained by Harris algorithm. With direct linear transformation and non-linear optimal algorithm, the global calibration pa-rameters are obtained. Then, a sub-regional method is proposed. Those corners are divided into two groups, middle corners and edge corners, which are used to calibrate the corresponding area to get two sets of calibration parameters. Finally, some experimental images are used to test the proposed method. Experimental results demonstrate that the average projection error of sub-region method is decreased at least 16% compared with the global calibration method. The proposed technique is simple and accurate. It is suitable for the industrial computer vision measurement.
