초록 ▼

This invention enables easy and fast selection of candidates for an inputted character image among the character categories by search of a tree-structured dictionary. Each ordinary node of the tree structure has three branches, that is two ordinary nodes and one reject node, and compares the multiva

This invention enables easy and fast selection of candidates for an inputted character image among the character categories by search of a tree-structured dictionary. Each ordinary node of the tree structure has three branches, that is two ordinary nodes and one reject node, and compares the multivalued feature extracted from the inputted character image for the node concerned, with a threshold, upper limit and lower limit values. If the feature value is out of the limited range, the search goes down to the reject node at the next level. If not, the search goes down to the right or left node at the next level based on the comparison of the feature value with the threshold value. Reject nodes have no branch. The tree structure has character category information as leaves connected to the bottom ordinary nodes and another character category information for all the reject nodes. Search of the dictionary gives character category information indicating the candidates, which are thereafter tested by detailed matching for outputting recognition results. In particular, this invention can use white pel run length as multivalued features. The white pel run length is defined as the run length of white pels from a point on an edge of the segmentation window to the nearest black pel or edge in a direction. It is easy to construct and optimize the dictionary, since many varieties of white run length are generated from little sampling data.

대표청구항 ▼

A character recognition apparatus wherein one or more character category candidates for an unknown character pattern are automatically determined through a search in a dictionary depending on multivalued features extracted from said pattern, comprising: a tree-structured dictionary further comprisin

A character recognition apparatus wherein one or more character category candidates for an unknown character pattern are automatically determined through a search in a dictionary depending on multivalued features extracted from said pattern, comprising: a tree-structured dictionary further comprising: nonterminal nodes, each having an assigned multivalued feature and a corresponding threshold value, at least one of said nonterminal nodes having a corresponding limit value; character category terminal nodes corresponding to at least one character category; and at least one reject terminal node which causes termination of said search; and means, at each nonterminal node responsive to the value of the assigned multivalued feature extracted from said unknown character pattern and corresponding limit and threshold values, for branching to the corresponding successor node, so that the branch will be made to the successor reject node if a limit value has been assigned to the nonterminal node and the value of the assigned multivalued feature is outside of the limit, and otherwise the branch will be made to the successor node based on the comparison of the value and the threshold value.