APPARATUS AND METHOD FOR EXTRACTING CIRCUMSCRIBED RECTANGLES OF CHARACTERS IN TRANSPLANTABLE ELECTRONIC DOCUMENT

• US 20110129157A1
• Filed: 11/23/2010
• Published: 06/02/2011
• Est. Priority Date: 11/27/2009
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Xu, Wenhui, Du, Cheng, Hasegawa, Fumihiro, Inoue, Koichi
• Granted Patent: US 8,452,097 B2
• Time in Patent Office: Days
• US Class Current: 382/203
• CPC Class Codes: G06F 40/109 Font handling; Temporal or kinetic typography
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/15 Cutting or merging image elements, e.g. region growing, watershed or clustering-based techniques

Abstract

Disclosed are an apparatus and a method for extracting circumscribed rectangles of one or more characters in a transplantable electronic document. The apparatus comprises a command and resource extraction device for extracting text-segment-related commands and original font resources; a division device for dividing the original font resources into fonts; a font replacement device for seeking fonts, and obtaining font resources after font replacement; a measurement information extraction device for extracting character shape measurement information of the characters; and a calculation device for calculating the circumscribed rectangles of the characters.

Claims

1. An apparatus for extracting circumscribed rectangles of one or more characters in a transplantable electronic document, comprising:

a command and resource extraction device configured to extract one or more text-segment-related commands and one or more original font resources corresponding to text segments in one or more pages of the transplantable electronic document;

a division device configured to divide the original font resources into one or more fonts that need to be replaced, and one or more fonts that do not need to be replaced, in which the fonts that need to be replaced serve as fonts prepared to be replaced;

a font replacement device configured to seek fonts most similar to the fonts prepared to be replaced based on the aspect of character shape measurement in an outer replacement font table as candidate fonts for replacing the fonts prepared to be replaced, and then let the candidate fonts and the fonts that do not need to be replaced make up font resources after font replacement;

a measurement information extraction device configured to extract character shape measurement information of the characters in the text segments based on the font resources after font replacement; and

a calculation device configured to calculate the circumscribed rectangles of the characters based on the text-segment-related commands and the character shape measurement information of the characters.

2. The apparatus according to claim 1, wherein, the command and resource extraction device comprises:

a content stream extraction unit configured to extract one or more content streams in the transplantable electronic documents, and then decode the content streams;

a command extraction unit configured to extract the text-segment-related commands in the decoded content streams; and

a font resource extraction unit configured to extract the original font resources corresponding to the text-segment-related commands from page resources of the transplantable electronic document.

3. The apparatus according to claim 1, wherein:

the division device lets fonts in the original font resource, lacking character shape measurement information, serve as the fonts prepared to be replaced.

4. The apparatus according to claim 1, wherein:

the font replacement device utilizes a matching approach to calculate similarities between fonts in the outer replacement font table, prepared to be selected and the fonts prepared to be replaced based on the aspect of character shape measurement, and then lets the fonts prepared to be selected having highest similarities serve as the candidate fonts.

5. The apparatus according to claim 1, wherein, the measurement information device comprises:

a character code table extraction unit configured to extract character code tables of the fonts from the font resource after font replacement;

a character shape measurement table extraction unit configured to extract character shape measurement tables of the fonts from font files after font replacement;

a character name obtaining unit configured to obtain character names corresponding to character codes from the character code tables based on the character codes; and

a character measurement information obtaining unit configured to obtain character shape measurement information corresponding to the obtained character names from the character shape measurement tables based on the character names.

6. The apparatus according to claim 1, wherein, the calculation device comprises:

a text segment measurement information extraction unit configured to extract text segment measurement information from the text-segment-related commands of the transplantable electronic document; and

a circumscribed rectangle calculation unit configured to calculate the circumscribed rectangles of the characters according to the text segment measurement information and the character shape measurement information of the characters.

7. The apparatus according to claim 1, wherein:

the transplantable electronic document is a PDF file.

8. A method of extracting circumscribed rectangles of one or more characters in a transplantable electronic document, comprising:

a command and resource extraction step of extracting one or more text-segment-related commands and one or more original font resources corresponding to text segments in one or more pages of the transplantable electronic document;

a division step of dividing the original font resources into one or more fonts that need to be replaced, and one or more fonts that do not need to be replaced, in which the fonts that need to be replaced serve as fonts prepared to be replaced;

a font replacement step of seeking fonts most similar to the fonts prepared to be replaced based on the aspect of character shape measurement in an outer replacement font table as candidate fonts for replacing the fonts prepared to be replaced, and then letting the candidate fonts and the fonts that do not need to be replaced make up font resources after font replacement;

a measurement information extraction step of extracting character shape measurement information of the characters in the text segments based on the font resources after font replacement; and

a calculation step of calculating the circumscribed rectangles of the characters based on the text-segment-related commands and the character shape measurement information of the characters.