最近傍探索についてのまとめ
ウィキペディア
http://ja.wikipedia.org/wiki/%E6%9C%80%E8%BF%91%E5%82%8D%E6%8E%A2%E7%B4%A2
ANN(A Library for Approximate Nearest Neighbor Searching)
http://www.cs.umd.edu/~mount/ANN/
FLANN(Fast Library for Approximate Nearest Neighbors)
http://mloss.org/software/view/143/