基于加权自学习散列的高维数据最近邻查询算法

因为查询和存储具有高效性,学习型散列逐渐被应用于解决最近邻查询问题.学习型散列将高维数据转化成二进制编码,并使得原始高维空间中越相似的数据对应二进制编码的汉明距离越小.在实际应用中,每次查询都会返回许多与查询点汉明距离相同而编码互不相同的数据.如何对这些数据进行排序是一个难题.提出了一种基于加权自学习散列的近邻查找算法.实验结果表明,算法能够高效地对具有相同汉明距离的不同编码进行重排序,加权排序后查询的F1值约是原来的2倍并优于同系算法,时间开销可比直接计算原始距离进行排序降低一个数量级.

Nearest neighbor search algorithm for high dimensional data based on weighted self-taught hashing

Because of efficiency in query and storage,learning hash is applied in solving the nearest neighbor search problem.The learning hash usually converts high-dimensional data into binary codes.In this way,the similarities between binary codes from two objects are conserved as they were in the original high-dimensional space.In practical applications,a lot of data which have the same distance from the query point but with different code will be returned.How to reorder these candidates is a problem.An algorithm named weighted self-taught hashing was proposed.Experimental results show that the proposed algorithm can reorder the different binary codes with the same Hamming distances efficiently.Compared to the naive algorithm,the F1-score of the proposed algorithm is improved by about 2 times and it is better than the homologous algorithms,furthermore,the time cost is reduced by an order of magnitude.