| 摘要 |
<p>Preferably using frame vectors, a reference memory (13) keeps feature vectors of a set as a tree comprising a root node, leaf nodes farthest from the root node, and intermediate nodes with the frame vectors assigned respectively to the leaf nodes. A calculator (17) calculates cluster distances between each feature vector of an input pattern and a subset assigned among the set to each daughter node of a mother node which is first the root node. From the intermediate nodes with the mother node successively selected along each branch of the tree, a selector (19) selects at least one daughter node that gives a shortest possible cluster distance. Controlling the calculator and the selector to use the cluster distances starting at each node selected nearest to the root node and proceeding along the branches to one of the leaf nodes that are used as daughter nodes of mother nodes selected nearest to the leaf nodes, a pattern distance calculator (15, 23) calculates pattern distances between the input pattern and reference patterns represented by the set. If the branches do not reach such leaf nodes, the cluster distances are used to the mother node last selected. Frame distributions of HMM may be used instead of the frame vectors. <IMAGE></p> |
