Image reading system and apparatus and method of reading image

An image reading apparatus comprising:

• a reading unit which reads out an original document;
• a document feeding unit which feeds the original document to an image reading position in the reading unit;
• a sheet detecting unit which is arranged upstream of the image reading position on a document feeding path of the document feeding unit and which detects passing of the original document;
• a start-of-reading instructing unit which instructs the reading unit to start reading at a position a predetermined distance before the position where a leading edge of the original document detected by the sheet detecting unit passes the image reading position;
• a termination-of-reading instructing unit which instructs the reading unit to terminate reading at a position a predetermined distance after the position where a trailing edge of the original document detected by the sheet detecting unit passes the image reading position;
• an extracting unit which extracts a rectangular area indicating a document image area of the original document from image data read out by the reading unit;
• an acquiring unit which acquires the number of apices of the rectangular area included in specific areas including a leading end and a trailing end of the image data;
• a determining unit which determines a sheet size of the original document on the basis of the result of the acquisition by the acquiring unit;
• and
• an output unit which outputs a rectangular area resulting from correction of the rectangular area to the sheet size of the original document determined by the determining unit as the document image area.

A method of controlling an image reading system including an image reading apparatus that includes a reading unit reading out an original document, a document feeding unit feeding the original document to an image reading position in the reading unit, and a sheet detecting unit that is arranged upstream of the image reading position on a document feeding path of the document feeding unit and that detects passing of the original document, the method comprising the steps of:

• instructing the reading unit to start reading at a position a predetermined distance before the position where a leading edge of the original document detected by the sheet detecting unit passes the image reading position;
• instructing the reading unit to terminate reading at a position a predetermined distance after the position where a trailing edge of the original document detected by the sheet detecting unit passes the image reading position;
• extracting a rectangular area indicating a document image area of the original document from image data read out by the reading unit;
• acquiring the number of apices of the rectangular area included in specific areas including a leading end and a trailing end of the image data;
• determining a sheet size of the original document on the basis of the result of the acquisition in the acquiring step;
• and
• outputting a rectangular area resulting from correction of the rectangular area to the sheet size of the original document determined in the determining step as the document image area.