RULED LINE EXTRACTION PROGRAM, RULED LINE EXTRACTION APPARATUS, AND RULED LINE EXTRACTION METHOD

PROBLEM TO BE SOLVED: To provide a ruled line extraction apparatus which can reextract a ruled line by changing a condition when reliability of a ruled line candidate extracted on the basis of a prescribed condition is low, and to provide a ruled line extraction program and a ruled line extraction method. SOLUTION: A computer is made to execute an extraction step for extracting a ruled line candidate which is the candidate of a ruled line from a document image on the basis of a first condition previously set as a condition which is to be satisfied by the graphic of a ruled line element, a decision step for deciding whether the ruled line candidate is stable or not on the basis of structure stability of the ruled line candidate extracted by the extraction step, a condition decision step for deciding a second condition which is a condition to be satisfied by the graphic of the ruled line element and different from the first condition on the basis of the ruled line candidate decided to be a stable candidate by the decision step and the first condition, and a reextraction step for reextracting the ruled line candidate on the basis of the second condition decided by the condition decision step. COPYRIGHT: (C)2008,JPO&INPIT