Optical character reading apparatus which can reduce reading errors as regards a character image if the character image is in contact with an unnecessary image.

• US 5,391,889 A
• Filed: 08/02/1993
• Issued: 02/21/1995
• Est. Priority Date: 08/05/1992
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Bashomatsu, Takeshi, Nishijima, Yasuo
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): LE, QUE TAN
• Application Number:
  US08/100,754
• Time in Patent Office: 568 Days
• Field of Search: 250/555, 250/556, 250/563, 250/566, 235/462, 235/472, 235/463, 382/9, 382/18
• US Class Current: 250/555
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/155 Removing patterns interfering with the pattern to be recognised, such as ruled lines or underlines

Abstract

In an optical character reading apparatus for optically reading a character image to produce a character signal representative of the character image, a collation and judgement circuit (22) compares a modified image with each of predetermined reference images memorized in a dictionary (21). A character detecting arrangement (11, 12) detects the character image to produce a detected image. A deleting arrangement (15, 16) partially deletes the detected image to produce a partially deleted image. A modifying arrangement (17, 18) modifies the partially deleted image into the modified image by the use of a reference signal produced in a reference signal producing arrangement (13, 14). It is preferable that the reference signal producing arrangement produces the reference signal in accordance with the detected image.

Claims

1. An optical character reading apparatus for optically reading a character image to produce a character signal representative of said character image, said apparatus including character detecting means for detecting said character image to produce a detected image, image processing means for processing said detected image into a processed image, memory means for memorizing a plurality of predetermined reference images, and comparison carrying out means for carrying out predetermined comparison between said processed image and each of said predetermined reference images to produce said character signal, wherein said image processing means comprises:

reference signal producing means for producing a reference signal;

deleting means connected to said character detecting means for partially deleting said detected image to produce a partially deleted image; and

modifying means connected to said reference signal producing, said deleting, and said comparison carrying out means for modifying said partially deleted image into a modified image by the use of said reference signal to supply said modified image as said processed image to said comparison carrying out means.

2. An optical character reading apparatus as claimed in claim 1, wherein said reference signal producing means is connected to said character detecting means and is for producing said reference signal in accordance with said detected image.

3. An optical character reading apparatus as claimed in claim 2, wherein said reference signal producing means comprises:

a first segmenting circuit connected to said character detecting means for segmenting said detected image to produce a first segmented image having a reference size; and

a size detecting circuit connected to said modifying means and said first segmenting circuit for detecting said reference size to produce a size signal representative of said reference size, said size detecting circuit supplying said size signal as said reference signal to said modifying means.

4. An optical character reading apparatus as claimed in claim 1, said detected image having an information part and a noise part which are partially overlapped each other, wherein said deleting means comprises:

a difference detecting circuit connected to said character detecting means for detecting difference between said information part and said noise part to produce a difference signal representative of said noise part; and

a noise deleting circuit connected to said modifying means and to said difference detecting circuit for deleting said noise part from said detected image with reference to said difference signal to produce said partially deleted image.

5. An optical character reading apparatus as claimed in claim 1, wherein said modifying means comprises:

a second segmenting circuit connected to said deleting means for segmenting said partially deleted image to produce a second segmented image; and

a local modifying circuit connected to said comparison carrying out and said reference signal producing means and to said second segmenting circuit for modifying said second segmented image into said modified image with reference to said reference signal.

6. An optical character reading apparatus as claimed in claim 1, wherein said modified image has a main part representative of a greater part of said character image and a supplementary part added to said main part, said comparison carrying out means comprises:

a part detecting circuit connected to said modifying means for detecting said supplementary part to produce a supplementary part signal; and

a local comparing circuit connected to said modifying and said memory means and to said part detecting circuit for carrying out said predetermined comparison with reference to said supplementary part signal so that said main part is compared with each of said predetermined reference images and that said supplementary part is not compared with each of said predetermined reference images, said local comparing circuit producing said character signal as a result of said comparison.