This invention relates to an apparatus and method for recognizing entered characters.
A conventional apparatus for recognizing handwritten characters compares the stroke pattern of an entered handwritten character with the stroke patterns of a recognition dictionary storing the strike patterns of standard characters, finds the character code that corresponds to the best matching stroke pattern based upon the results of comparison and outputs this character code as the result of recognition. When similar handwritten characters whose stroke patterns are not very different from each other, such as the characters "3" and "" (the latter of which is a hiragana character), have been entered, the portions of these similar characters that differ from each other are extracted as feature quantities. An extracted feature quantity is compared with a predetermined threshold value (calculated based upon the stroke patterns of standard characters) that is for identifying similar characters, thereby making it possible to identify similar characters.
Depending upon the user, there are occasions where the entered stroke pattern of a handwritten character differs greatly from the stroke patterns of standard characters. Depending upon the user, therefore, instances arise in which an entered character cannot be recognized. Accordingly, a user dictionary is created by registering the stroke patterns of handwritten characters entered by the user, the features of these stroke patterns and the corresponding character codes. Comparing the stroke patterns registered in the user dictionary and the stroke patterns of entered handwritten patterns makes feasible the recognition of stroke patterns of handwritten characters that differ greatly from the stroke patterns of standard characters.
With the conventional handwritten character recognition apparatus of the kind described above, however, the identification of similar characters is carried out by comparing feature quantities obtained from the similar characters and predetermined threshold values (feature quantities) established in advance. Consequently, if the feature quantities obtained from similar characters entered by a user are not of a uniform nature, the identification of similar characters cannot be performed accurately.
Further, in case of character recognition employing a user dictionary, only the stroke patterns of entered handwritten characters and their features are registered in the dictionary. Even if similar characters are present among the characters registered, extraction of features that takes into account the identification of one similar character from another is not carried out. Consequently, not only is there no improvement in the precision of recognition of similar handwritten characters but there are also cases in which similar characters cannot be recognized at all.