Image forming apparatus capable of recognizing top and bottom of document image

• US 6,266,441 B1
• Filed: 03/26/1999
• Issued: 07/24/2001
• Est. Priority Date: 05/23/1995
• Status: Expired due to Fees

• Current Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Original Assignee: Minolta Corporation Limited (Konica Minolta Inc.)
• Inventors: Imaizumi, Shoji, Sakatani, Kazuomi, Nabeshima, Takayuki, Hashimoto, Hideyuki
• Primary Examiner(s): Boudreau, Leo
• Assistant Examiner(s): Mariam, Daniel G.
• Application Number:
  US09/276,750
• Time in Patent Office: 851 Days
• Field of Search: 382/170, 382/168, 382/289, 382/290, 382/291, 382/151, 358/486, 358/487, 358/522, 358/488
• US Class Current: 382/170
• CPC Class Codes: G06V 10/242 by image rotation, e.g. by 90 degrees

Abstract

An image forming apparatus automatically identifying top and bottom of document image based on characteristics with regard to shapes or positions of data, etc. recorded on document. Distribution states of pixel cumulative values in main scanning direction and sub scanning direction of image signals provided by scanning the document, are analyzed and top and bottom of the document image is identified from the result of analysis. Further, it is possible to identify the top and bottom of the document image by analyzing the distribution states the pixel cumulative values in the main scanning direction and the sub scanning direction of the image signals and identifying letter series regions and line segment regions displaced therefrom. In addition thereto, it is possible to automatically identify the top and bottom of the document image based on distribution states in the main scanning direction and the sub scanning direction of specific signs included in the image signals provided by scanning the document or distribution states of pixel cumulative values of specific image regions including the specific signs.

Claims

1. An image forming apparatus comprising:

an image data memory for storing pixel image data of a document;

detecting means for detecting a specific pattern included in the document;

investigating means for investigating the locations and the frequency of occurrence of the specific pattern detected by said detecting means;

determining means for determining a direction of the document based on a result of investigation by said investigating means; and

controlling means for processing the pixel image data in accordance with a result of determination by the determining means.

2. An image forming apparatus according to claim 1, wherein the investigating means comprises a first histogram forming means for forming a first histogram indicating the distribution state of the specific pattern in a first direction and a second histogram forming means for forming a second histogram indicating the distribution state of the specific pattern in a second direction.

3. An image forming apparatus according to claim 1, further comprising a specific pattern memory for prestoring a specific pattern, and a specific pattern designating means for designating the specific pattern.

4. An image forming apparatus according to claim 1, wherein the determining means determines that the determination of the direction of the document cannot be performed when the specific pattern is not detected in the document.

5. An image forming apparatus according to claim 1, wherein the specific pattern is a pattern having no characteristics in either of a first direction and a second direction.

6. The method according to claim 1, wherein the step of investigating comprises forming a first histogram indicating the distribution state of the specific pattern in a first direction and forming a second histogram indicating the distribution state of the specific pattern in a second direction.

7. A method of processing pixel image data of a document, comprising:

storing the pixel image data of the document;

detecting a specific pattern included in the document;

investigating the locations and the frequency of occurrence of the detected specific pattern;

determining a direction of the document based on a result of investigation by said investigating step; and

processing the pixel image data in accordance with a result of the determining step.