| 摘要 |
PROBLEM TO BE SOLVED: To provide an image reading apparatus capable of removing a show-through image generated due to the reading of a document independently of the thickness and sort of the document. SOLUTION: An image reading unit 15 corresponding to both-side simultaneous reading of a document 20 is provided with an A-face reading part 15A for reading out the A-face (surface) of the document 20 and a B-face reading part 15B for reading out the B-face (rear) of the document 20. The A-face reading part 15A is configured so that the A-face of the document 20 which is backed by reflectors 22a<SB>1</SB>, 22a<SB>2</SB>having respectively different reflection factors and illuminated by light sources 21a<SB>1</SB>, 21a<SB>2</SB>is read out by respective sensors 23a<SB>1</SB>, 23a<SB>2</SB>. The B-face reading part 15B is configured so that the B-face of the document 20 which is backed by reflectors 22b<SB>1</SB>, 22b<SB>2</SB>having respectively different reflection factors and illuminated by light sources 21b<SB>1</SB>, 21b<SB>2</SB>is read out by respective sensors 23b<SB>1</SB>, 23b<SB>2</SB>. By using these four read images, a show-through coefficient indicating a degree of show-through effects including the transmissivity of the document and a rear reflection factor is calculated to remove a show-through image component. COPYRIGHT: (C)2009,JPO&INPIT |
