Depth from defocus(DFD),as a typical shape reconstruction method,has been widely researched in most recent years.However,all the existing DFD algorithms require at least two defocused images with different camera para...Depth from defocus(DFD),as a typical shape reconstruction method,has been widely researched in most recent years.However,all the existing DFD algorithms require at least two defocused images with different camera parameters.Unfortunately,in micro/nano manipulation,any change on visual sensor's parameters is absolutely forbidden.Therefore,a novel DFD method to reconstruct the shape of a nano grid on micro/nano scale is researched in this paper.First,the blurring imaging model is constructed with the relative blurring and the diffusion equation.Second,the relationship between depth and blurring is discussed from four aspects.Subsequently,depth measurement problem is transformed into an optimization issue which is solved using the gradient flow algorithm.Finally,experiment results and error analysis are conducted to show the feasibility and effectiveness of the proposed method.展开更多
In order to model the hysteresis behavior of a nano piezoelectric actuator(PA)on nano scale in a real time system,a new hysteresis modeling method based on an improved sub-pixel blocking matching algorithm with an opt...In order to model the hysteresis behavior of a nano piezoelectric actuator(PA)on nano scale in a real time system,a new hysteresis modeling method based on an improved sub-pixel blocking matching algorithm with an optimal block size is proposed in this paper.First,Preisach model is introduced to model the hysteresis behavior of a piezoelectric actuator.Then,a real time block matching algorithm is researched and its block size is optimized with a standard object.Finally,experiments are performed with respect to a nanometer movement platform system,and the results show the feasibility and validity of the sub-pixel estimation based block matching algorithm and its application in modeling the hysteresis behavior of PA.展开更多
Atomic force microscope （AFM）, as an important instrument in micro/nano operation, has been widely used to measure sampie＇s height information. However, the so called compression effect, due to force aroused from t...Atomic force microscope （AFM）, as an important instrument in micro/nano operation, has been widely used to measure sampie＇s height information. However, the so called compression effect, due to force aroused from the contact of AFM tip with a sample surface, would result in imprecision of the surface＇s height measurement, i.e., the measured height is lower than expected. Up to now, there is not any effective and rapid method to attenuate this kind of measurement error. Thus, in this paper, an algorithm to obtain high accurate height measurement is proposed. Firstly, the concept of force curve is used to analyze the basic principle of the compression effect. Secondly, an automatic compensation method by fusing the height signal and the deflection signal is proposed. The proposed algorithm can also be used to obtain a surface elasticity image. Finally, in order to validate the proposed method, two experiments are conducted with respect to mufti-wall nano-carbon tubes on a silicon substrate and graphemes on a mica substrate.展开更多
文摘随着机器人操作系统(robot operating system, ROS)的日益普及,系统也变得更加复杂,这类系统的计算平台正逐渐转变为多核心平台.在ROS中,任务执行的顺序取决于底层任务调度策略和分配给任务的优先级,而最大限度地缩短所有任务的执行时间是并行系统任务调度的一个重要目标.受强化学习在解决各种组合优化问题的最新研究成果的启发,在考虑ROS2多线程执行器的调度机制和执行约束的前提下,提出了一种基于强化学习的任务优先级分配方法,该方法提取了基于有向无环图形式表示的任务集的时间和结构特征,通过策略梯度和蒙特卡洛树搜索(Monte Carlo tree search, MCTS)方法有效地学习ROS2调度策略并给出合理的优先级设置方案,最终达到最小化并行任务的最大完工时间的目的.通过模拟平台环境下随机生成的任务图以评估所提方法,结果表明所提方法明显优于基准方法.作为一种离线分析方法,所提方法可以很容易地扩展到复杂的ROS中,在可接受的时间内找到接近最优的解决方案.
文摘视频合成孔径雷达(video synthetic aperture radar,VideoSAR)的超长相干孔径观测使得区域动态信息的快速浏览极其困难。为以机器视觉方式自动捕捉地物散射消失-瞬态持续-消失-瞬态持续-消失的关键帧变化全过程,提出了一种子孔径能量梯度(subaperture energy gradient,SEG)和低秩与稀疏分解(low-rank plus sparse decomposition,LRSD)相结合的VideoSAR关键帧提取器。提取器为系列性通用架构,适用于任何SEG和LRSD系列方法相结合的形式。所提技术首要针对同时单通道、单波段、单航迹等有限信息条件的解决途径,有助于打破应急响应场景中难以采集多通道、多波段、多航迹或多传感器数据的应用局限性。基于实测数据处理和多种先进LRSD算法进行了对比验证,其代表性散射信息的充分提取可促进未来快速地理解并浓缩区域动态。
基金supported by the CAS FEA international partnership program for creative research teams
文摘Depth from defocus(DFD),as a typical shape reconstruction method,has been widely researched in most recent years.However,all the existing DFD algorithms require at least two defocused images with different camera parameters.Unfortunately,in micro/nano manipulation,any change on visual sensor's parameters is absolutely forbidden.Therefore,a novel DFD method to reconstruct the shape of a nano grid on micro/nano scale is researched in this paper.First,the blurring imaging model is constructed with the relative blurring and the diffusion equation.Second,the relationship between depth and blurring is discussed from four aspects.Subsequently,depth measurement problem is transformed into an optimization issue which is solved using the gradient flow algorithm.Finally,experiment results and error analysis are conducted to show the feasibility and effectiveness of the proposed method.
基金supported by the National Natural Science Foundation of China(Grant No.61305025)
文摘In order to model the hysteresis behavior of a nano piezoelectric actuator(PA)on nano scale in a real time system,a new hysteresis modeling method based on an improved sub-pixel blocking matching algorithm with an optimal block size is proposed in this paper.First,Preisach model is introduced to model the hysteresis behavior of a piezoelectric actuator.Then,a real time block matching algorithm is researched and its block size is optimized with a standard object.Finally,experiments are performed with respect to a nanometer movement platform system,and the results show the feasibility and validity of the sub-pixel estimation based block matching algorithm and its application in modeling the hysteresis behavior of PA.
基金supported by the CAS FEA International Partnership Program for Creative Research Teams
文摘Atomic force microscope （AFM）, as an important instrument in micro/nano operation, has been widely used to measure sampie＇s height information. However, the so called compression effect, due to force aroused from the contact of AFM tip with a sample surface, would result in imprecision of the surface＇s height measurement, i.e., the measured height is lower than expected. Up to now, there is not any effective and rapid method to attenuate this kind of measurement error. Thus, in this paper, an algorithm to obtain high accurate height measurement is proposed. Firstly, the concept of force curve is used to analyze the basic principle of the compression effect. Secondly, an automatic compensation method by fusing the height signal and the deflection signal is proposed. The proposed algorithm can also be used to obtain a surface elasticity image. Finally, in order to validate the proposed method, two experiments are conducted with respect to mufti-wall nano-carbon tubes on a silicon substrate and graphemes on a mica substrate.
