摘要
现代宽视场光学瞬变源巡天的大数据量特性和数据处理的高实时性要求,对利用星表交叉证认寻找瞬变源的方法提出了挑战。提出了一种基于等经纬分区建立空间索引的快速星表交叉证认算法。该算法通过对参考星表按相同经度和纬度间隔将视场所覆盖的天区划分为一个二维空间网格,并将二维网格直接与二维数组相对应,建立起星表的快速分区索引,从而实现处理速度的极大提升。算法的代码化测试结果为:对于天区覆盖为15°×15°记录条数为22万条的星表,在Intel Core i7 2600k CPU上的运行时间为0.3 s,比多级三角划分算法(Hierarchical Triangular Mesh,HTM)快34倍。测试结果表明该算法能很好地满足,如地面广角相机阵这样的大型宽场瞬变源巡天项目的数据处理实时性需求。同时详细地分析了算法中各个参数的意义和优化方法,并对算法的特点和适用范围进行了深入的讨论。
With the development of modem wide-field optical transient （OT） surveys, the traditional methods of cross identification are facing a great challenge in real-time search of OT sources from data of large volumes. To overcome the difficulties encountered by the traditional methods, we propose a novel algorithm to speed up the search. This algorithm divides the sky coverage of the object catalog into a grid of regions with a constant size in both Right-Ascension （RA） and Declination （Dec） directions. It uses a fast approach to index the grid regions, and maps them into a two-dimensional array in the computer memory. Our tests show that it takes the algorithm 0.3 seconds to perform cross identification in a catalog of 220 000 records if run on a computer of an Intel Core i7 2600k CPU. This is about 34 times faster than the HTM algorithm. This indicates that our algorithm can meet the requirements on fast real-time OT-source search in a modem wide- field OT survey project, such as the Chinese Ground Wide-Angle Camera （GWAC） project. We also explain in detail the parameters of the functions of the algorithm and specify the optimal values of the parameters. We finally discuss the scope of applications and certain features of the algorithm.
出处
《天文研究与技术》
CSCD
2013年第3期273-282,共10页
Astronomical Research & Technology
基金
国家自然科学基金(10903010)
国家自然科学天文联合基金(U1231123)
三峡大学启动经费(KJ2011B069)
三峡大学研究生科研创新基金(2011CX050)资助
关键词
天文数据处理
交叉证认
等间隔分区
星表匹配
数组索引
Astronomical data processing
Cross identification
Division with even intervals
Catalog crossidentification
Array indexing
