Document image processing apparatus, document image processing method, and computer-readable recording medium having recorded document image processing program

A document image processing method executed by a document image processing apparatus comprising a memory storing a document image, to extract an index region from said document image stored in said memory, and comprising the steps of:

• classifying a plurality of character string element regions constituting said document image into small regions and large regions;
• determining each small region positioned just before said large region according to a reading order as a first candidate;
• determining at least one part of said first candidates as a first index, by performing an evaluating process to evaluate whether or not each said first candidate is an index, based on a difference in feature from the related large region, with respect to each said first candidate;
• determining each small region positioned just before said first index according to the reading order as a second candidate;
• determining at least one part of said second candidates as a second index, by performing an evaluating process to evaluate whether or not said second candidate is the index, based on a difference in feature from the related first index, with respect to each said second candidate;
• and
• extracting the small regions determined as said first index and said second index, as said index region.

A computer-readable recording medium having a recorded document image processing program comprising the steps of:

• classifying a plurality of character string element regions constituting a document image into small regions and large regions;
• determining each small region positioned just before said large region according to a reading order as a first candidate;
• determining at least one part of said first candidates as a first index, by performing an evaluating process to evaluate whether or not each said first candidate is an index, based on a difference in feature from the related large region, with respect to each said first candidate;
• determining each small region positioned just before said first index according to the reading order as a second candidate;
• determining at least one part of said second candidates as a second index, by performing an evaluating process to evaluate whether or not said second candidate is the index, based on a difference in feature from the related first index, with respect to each said second candidate;
• and
• extracting the small regions determined as said first index and said second index, as said index region.