为了在集中器、专变终端等嵌入式系统中更高效地完成校时任务,文章基于网络时间协议(Network Time Protocol,NTP)的基本工作原理,结合智能用电信息采集系统(Advanced Metering Infrastructure,AMI)的网络延时特点,给出了AMI的终端NTP基...为了在集中器、专变终端等嵌入式系统中更高效地完成校时任务,文章基于网络时间协议(Network Time Protocol,NTP)的基本工作原理,结合智能用电信息采集系统(Advanced Metering Infrastructure,AMI)的网络延时特点,给出了AMI的终端NTP基本校时算法。针对NTP时间同步算法在处理网络延时中的不足,提出了几种改进的校时策略,不仅提高了校时的准确性和稳定性,而且大幅度降低了工程计算量,从而可以更好的应用于嵌入式系统。首先使用最大似然估计法得出了多次NTP校时的时间偏差最优估计,然后分别介绍了去边缘值、均值滚动筛选和样本滤波方法来进一步改进校时策略。经实验验证,使用所提出的校时策略进行校时,校时误差最大仅为525ms,完全能把校时精度控制在1s以内,并有较好的校时准确性和稳定性,能充分适配嵌入式系统并满足了AMI终端的校时要求。展开更多
To solve the problem that the accurate information of hand cannot be obtained by particle filter, a hand tracking algorithm based on particle filter combined with skin-color adaptive gradient vector flow(GVF) snake mo...To solve the problem that the accurate information of hand cannot be obtained by particle filter, a hand tracking algorithm based on particle filter combined with skin-color adaptive gradient vector flow(GVF) snake model is proposed. Adaptive GVF and skin color adaptive external guidance force are introduced to the traditional GVF snake model, guiding the curve to quickly converge to the deep concave region of hand contour and obtaining the complex hand contour accurately. This algorithm realizes a real-time correction of the particle filter parameters, avoiding the particle drift phenomenon. Experimental results show that the proposed algorithm can reduce the root mean square error of the hand tracking by 53%, and improve the accuracy of hand tracking in the case of complex and moving background, even with a large range of occlusion.展开更多
文摘为了在集中器、专变终端等嵌入式系统中更高效地完成校时任务,文章基于网络时间协议(Network Time Protocol,NTP)的基本工作原理,结合智能用电信息采集系统(Advanced Metering Infrastructure,AMI)的网络延时特点,给出了AMI的终端NTP基本校时算法。针对NTP时间同步算法在处理网络延时中的不足,提出了几种改进的校时策略,不仅提高了校时的准确性和稳定性,而且大幅度降低了工程计算量,从而可以更好的应用于嵌入式系统。首先使用最大似然估计法得出了多次NTP校时的时间偏差最优估计,然后分别介绍了去边缘值、均值滚动筛选和样本滤波方法来进一步改进校时策略。经实验验证,使用所提出的校时策略进行校时,校时误差最大仅为525ms,完全能把校时精度控制在1s以内,并有较好的校时准确性和稳定性,能充分适配嵌入式系统并满足了AMI终端的校时要求。
基金supported by the National Natural Sciencal Foundation of China(No.61403274)the Tianjin Technology Project of Intelligent Manufacturing(No.15ZXZNGX00160)
文摘To solve the problem that the accurate information of hand cannot be obtained by particle filter, a hand tracking algorithm based on particle filter combined with skin-color adaptive gradient vector flow(GVF) snake model is proposed. Adaptive GVF and skin color adaptive external guidance force are introduced to the traditional GVF snake model, guiding the curve to quickly converge to the deep concave region of hand contour and obtaining the complex hand contour accurately. This algorithm realizes a real-time correction of the particle filter parameters, avoiding the particle drift phenomenon. Experimental results show that the proposed algorithm can reduce the root mean square error of the hand tracking by 53%, and improve the accuracy of hand tracking in the case of complex and moving background, even with a large range of occlusion.
