Patent ID: 7191177

Claim:
A computer implemented keyword extracting device comprising: a text data input part for inputting a text, a pattern storage part storing at least a pattern to generate keyword candidates, said pattern is represented by character strings in regular expression or its equivalent, an extracting part for extracting character strings from the text through pattern matching using said pattern stored in said pattern storage part, a keyword candidate generating part generating keyword candidates, the keyword candidates including at least portions of the character strings being extracted at the extracting part, and an output part outputting the keyword candidates as keywords, wherein the pattern to generate keyword candidates is an unnecessary pattern representing unnecessary head or end character strings, the keyword candidate generating part includes an unnecessary character string removing part, and said unnecessary character string removing part extracts keyword candidates including character strings matched with the unnecessary pattern from the keyword candidates so that (i) if the extracted keyword candidates are same as character strings matched with the unnecessary pattern, removes the extracted keyword candidates, and (ii) if the extracted keyword candidates are not same as character strings matched with the unnecessary pattern, takes the keyword candidates, in which said matched character string is removed, as a keyword candidates.