An efficient approximation-elimination algorithm for fast nearest-neighbour search based on a spherical distance coordinate formulation

Ramasubramanian, V. and K.K. Paliwal, An efficient approximation-elimination algorithm for fast nearest-neighbour search based on a spherical distance coordinate formulation, Pattern Recognition Letters 13 (1992) 471-480. An efficient approximation-elimination search algorithm for fast nearest-neighbour search is proposed based on a spherical distance coordinate formuTation, where a vector in K-dimensional space is represented uniquely by its distances from K + I fixed points. The proposed algorithm uses triangle-inequality based elimination rules which is applicable for search using metric distances measures, it is a more efficient fixed point equivalent of the Approximation Elimination Search AIgoritlun (AESA) proposed earlier by Vidal [2]. in comparison to AESA which has a very high O(N 2) storage complexity, the proposed algorithm uses only O(N) storage with very low approximation-elimination computational overheads while achieving complexity reductions closely comparable to AESA, The algorithm is used for fast vector quantization of :;i',,xd, waw:i'u,m~; a~d is observed to have O(K + 1) average complexity.