System for aligning document images when scanned in duplex mode

• US 6,067,385 A
• Filed: 05/07/1997
• Issued: 05/23/2000
• Est. Priority Date: 05/07/1997
• Status: Expired due to Term

• Current Assignee: Ricoh Company Limited, Ricoh Corporation (Ricoh Company Limited)
• Original Assignee: Ricoh Company Limited, Ricoh Corporation (Ricoh Company Limited)
• Inventors: Hull, Jonathan J., Peairs, Mark, Cullen, John F.
• Primary Examiner(s): ROGERS, SCOTT A
• Application Number:
  US08/852,489
• Time in Patent Office: 1,112 Days
• Field of Search: 382/275, 382/217, 382/218, 382/219, 382/209, 382/254, 382/260, 382/263, 382/264, 358/464, 358/463, 358/448, 358/401, 358/296, 358/487, 358/447, 358/465
• US Class Current: 382/275
• CPC Class Codes: H04N 1/00572 with refeeding for double-sided scanning, e.g. using one scanning head for both sides of a sheet
• CPC Class Codes: H04N 1/00575 Inverting the sheet prior to refeeding
• CPC Class Codes: H04N 1/047 Detection, control or error compensation of scanning velocity or position H04N1/0402 and H04N1/17 take precedence
• CPC Class Codes: H04N 1/12 using the sheet-feed movement or the medium-advance or the drum-rotation movement as the slow scanning component, e.g. arrangements for the main-scanningsheet-feed movement by translatory movement of a flat picture-bearing surface H04N1/1008; main-scanning using oscillating or rotating mirrors H04N1/113; using multi-element arrays H04N1/19
• CPC Class Codes: H04N 1/32609 Fault detection or counter-measures, e.g. original mis-positioned, shortage of paper
• CPC Class Codes: H04N 1/3263 of reading apparatus or transmitter, e.g. original jam
• CPC Class Codes: H04N 1/32657 locally
• CPC Class Codes: H04N 1/40 Picture signal circuits H04N1/387 takes precedence
• CPC Class Codes: H04N 1/4095 Correction of errors due to scanning a two-sided document, i.e. show-through correction
• CPC Class Codes: H04N 2201/04703 using the scanning elements as detectors, e.g. by performing a prescan
• CPC Class Codes: H04N 2201/04743 by detecting the image directly
• CPC Class Codes: H04N 2201/04787 by changing or controlling the addresses or values of pixels, e.g. in an array, in a memory, by interpolation

Abstract

A system and method for handling duplex documents by exploiting bleed-through of the image on the back side of a document. The images of the back sides and front sides of documents are associated with one another to assure correct output in copying, faxing, scanning, etc. This increases reliability, eases recovery from errors including paper jams. Improved document handling capabilities also include avoiding twice duplicated and skipped pages and correcting page orientation errors.

Claims

1. A method for processing a multi-page document comprising:

scanning in front sides of a plurality of pages of said multi-page document to develop front scan image data for each of said front sides;

for each of said front sides, identifying in said front scan image data, regions corresponding to printed matter on said front sides;

developing bleed-through image data for each of said front sides from said front scan image data of said front sides;

scanning in back sides of said plurality of pages of said multi-page document to develop back scan image data for each of said back sides; and

matching said back scan image data for said back sides to said bleed-through image data for the front sides to identify matching front and back sides.

2. The method of claim 1 wherein said bleed-through image data includes printed regions not occluded by said regions corresponding to printed matter of said front sides.

3. The method of claim 1 further comprising:

controlling reproduction of said multi-page document responsive to results of said matching step.

4. The method of claim 1 further comprising:

controlling faxing of said multi-page document responsive to results of said matching step.

5. A document processing system comprising:

a scanner that scans in front sides of a plurality of pages of said multi-page document to develop front scan image data for each of said front side and scans in back sides of said plurality of pages of said multi-page document to develop back scan image data for each of said back sides; and

an image processing system that

a) for each of said front sides, identifies in said front scan image data, regions corresponding to printed matter on said front sides;

b) develops a bleed-through image data for each of said front sides from said front scan image data of said front sides; and

c) matches said back scan image data for said back sides to said bleed-through image data for the front sides to identify matching front and back sides.

6. The document processing system of claim 5 wherein said bleed-through image data includes printed regions not occluded by said regions corresponding to printed matter of said front sides.

7. The document processing system of claim 5 wherein said image processing system further controls document reproduction responsive to said matching front and back sides.

8. The document processing system of claim 5 wherein said image processing system further controls document faxing responsive to said matching front and back sides.

9. A method for processing a plurality of pages, each page of the plurality of pages having a first side and a second side, the method comprising:

providing first scan image data for each page of the plurality of pages, the first scan image data including image information obtained by scanning the first side of the page;

identifying first side image data for each page of the plurality of pages from the first scan image data for the page, the first side image data including images printed on the first side of the page;

identifying bleed-through image data for each page of the plurality of pages from the first scan image data for the page;

providing second scan image data for each page of the plurality of pages, the second scan image data including image information obtained by scanning the second side of the page;

identifying second side image data for each page of the plurality of pages from the second scan image data for the page, the second side image data including images printed on the second side of the page; and

processing the second side image data and the bleed-through image data for the plurality of pages to identify at least one matching first side image data and second side image data, wherein the first side image data and second side image data are matching if the first side image data corresponds to images printed on the first side of a page from the plurality of pages and the second side image data corresponds to images printed on the second side of the page.

10. A method for processing a plurality of pages, each page of the plurality of pages having a first side and a second side, the method comprising:

obtaining first side image data and bleed-through data for each page of the plurality of pages by scanning the first sides of the plurality of pages, wherein the first side image data includes images printed on the first side of each page;

obtaining second side image data for each page of the plurality of pages by scanning the second sides of the plurality of pages; and

processing the second side image data and the bleed-through image data for the plurality of pages to identify at least one matching first side image data and second side image data, wherein the first side image data and second side image data are matching if the first side image data corresponds to images printed on the first side of a page from the plurality of pages and the second side image data corresponds to images printed on the second side of the page.

11. A computer program product for processing a multi-page document comprising:

code for scanning in front sides of a plurality of pages of said multi-page document to develop front scan image data for each of said front sides;

for each of said front sides, code for identifying in said corresponding front scan image data, regions corresponding to printed matter on said front sides;

code for developing bleed-through image data for each of said front sides from said front scan image data for said front sides;

code for scanning in back sides of said plurality of pages of said multi-page document to develop back scan image data for each of said back sides;

code for matching said back scan image data for said back sides to said bleed-through image data for the front sides to identify matching front and back sides; and

a computer-readable medium for storing the codes.

12. A computer program product for processing a plurality of pages, each page of the plurality of pages having a first side and a second side, the program product comprising:

code for providing first scan image data for each page of the plurality of pages, the first scan image data including image information obtained by scanning the first side of the page;

code for identifying first side image data for each page of the plurality of pages from the first scan image data for the page, the first side image data including images printed on the first side of the page;

code for identifying bleed-through image data for each page of the plurality of pages from the first scan image data for the page;

code for providing second scan image data for each page of the plurality of pages, the second scan image data including image information obtained by scanning the second side of the page;

code for identifying second side image data for each page of the plurality of pages from the second scan image data for the page, the second side image data including images printed on the second side of the page;

code for processing the second side image data and the bleed-through image data to identify at least one matching first side image data and second side image data, wherein the first side image data and second side image data are matching if the first side image data corresponds to images printed on the first side of a page from the plurality of pages and the second side image data corresponds to images printed on the second side of the page; and

a computer-readable medium for storing the codes.

13. A computer program product for processing a plurality of pages, each page of the plurality of pages having a first side and a second side, the program product comprising:

code for obtaining first side image data and bleed-through data for each page of the plurality of pages by scanning the first sides of the plurality of pages, wherein the first side image data includes images printed on the first side of each page;

code for obtaining second side image data for each page of the plurality of pages by scanning the second sides of the plurality of pages;

code for processing the second side image data and the bleed-through image data for the plurality of pages to identify at least one matching first side image data and second side image data, wherein the first side image data and second side image data are matching if the first side image data corresponds to images printed on the first side of a page from the plurality of pages and the second side image data corresponds to images printed on the second side of the page; and

a computer-readable medium for storing the codes.