QQ客服 官方微博 反馈留言

浏览/检索结果: 共4条，第1-4条 帮助 已选(0)清除 条数/页：5101520253035404550556065707580859095100   排序方式：请选择作者升序作者降序题名升序题名降序发表日期升序发表日期降序提交时间升序提交时间降序 An improved two-dimensional entropy method for star trail tracing in deep sky (EI CONFERENCE) 会议论文 ICO20: Optical Information Processing, August 21, 2005 - August 26, 2005, Changchun, China Yao Z.-J.; Wang Y.-J.; Han Q.-L. 收藏  |  浏览/下载：16/0  |  提交时间：2013/03/25 The trace of star trail is an important component of deep sky detection. The stars are low contrast targets  and their self-rotation will make their brightness change in cycle. Above all  the trail trace is vulnerable to the block and disturbance of other stars. Traditional one-dimensional maximum entropy thresholding algorithm is vulnerable to the noise  and the calculation of two-dimensional entropy methods is too large and takes too much time. This paper proposes an improved two-dimensional entropy threshold algorithm. We use recursion iteration method to eliminate the redundancy calculation  and reduce the size of two-dimensional histogram based on the deep sky stars characteristic  such as low contrast  fuzziness and the centralized histogram. We also combine our algorithm with the space trail trace model to forecast the star trace. Experiments results show  when the star are blocked or they turn dark  the method still can well extrapolate the star trace. Our method improves the capability of trailing the ebb and small star  and increases the precision of tracing. It is also robust to the noise  so there is a good application foreground for the method.   Stability of implicit one-block methods for delay differential equations 期刊论文 APPLIED NUMERICAL MATHEMATICS, 2001, 卷号: 36, 期号: 2-3, 页码: 275-279 作者:  Zhang, GF 收藏  |  浏览/下载：2/0  |  提交时间：2015/12/16 delay differential equations  one-block methods  numerical solution  linear stability analysis   The convergence of two Newton-like methods for solving block nonlinear equations and a class of r-point (r+1)st-order A-stable one-block methods 期刊论文 APPLIED NUMERICAL MATHEMATICS, 1997, 卷号: 25, 期号: 1, 页码: 117-133 作者:  Zhao, SS;  Zhang, GF;  Wang, CY 收藏  |  浏览/下载：2/0  |  提交时间：2015/12/16 one-block methods  stiff ODEs  A-stability  Newton-like method  parallel computation   The convergence of two Newton-like methods for solving block nonlinear equations and a class of r-point (r+1)st-order A-stable one-block methods 期刊论文 APPLIED NUMERICAL MATHEMATICS, 1997, 卷号: 25, 期号: 1, 页码: 117-133 作者:  Zhao, SS;  Zhang, GF;  Wang, CY 收藏  |  浏览/下载：7/0  |  提交时间：2019/11/15 one-block methods  stiff ODEs  A-stability  Newton-like method  parallel computation