US20140168732A1 - Verifying accuracy of a scanned document - Google Patents

Abstract

A document scanner (10) includes an input tray (30) for holding documents (20) and an input image capture device (40) for capturing images of the documents (20)in the input tray (30) prior to transporting the document for imaging; an output tray (150) for holding documents (20) after the documents (20) exit the scanner; an output image capture device (140) for capturing images of the output tray; an image processor for determining characteristics of the output tray or characteristic of the documents (20) before imaging and after the documents (20) exit the scanner; and scanner functions are modified based on the output tray characteristics or the document characteristics.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• Reference is made to commonly-assigned copending U.S. patent application Ser. No. ______ (Attorney Docket No. K001409US01NAB), filed herewith, entitled METHOD OF CAPTURING AN IMAGE OF A DOCUMENT, by Schaertel et al.; U.S. patent application Ser. No. ______ (Attorney Docket No. K001410US01NAB), filed herewith, entitled SYSTEM FOR VERIFYING ACCURACY OF A RASTER SCANNED IMAGE OF A DOCUMENT, by Schaertel et al.; U.S. patent application Ser. No. ______ (Attorney Docket No. K001411USO1NAB), filed herewith, entitled SYSTEM FOR CAPTURING AN IMAGE OF A DOCUMENT, by Schaertel et al.; U.S. patent application Ser. No. 12/858,488 (now U.S. Publication No. 2012/0044547), filed Aug. 18, 2010, entitled A DOCUMENT SCANNER, by Schaertel et al.; U.S. Patent Application Serial No. 12/839,476, filed July 20, 2010, entitled METHOD FOR DOCUMENT SCANNING, by Schaertel et al.; U.S. patent application Ser. No. 12/839,471, filed Jul. 20, 2010, entitled A DOCUMENT SCANNER, by Schaertel et al.; and U.S. patent application Ser. No. 12/276,641 (now U.S. Publication No. 2010/0127447), filed Nov. 24, 2008, entitled DOCUMENT TRANSPORT APPARTUS, by Hammen; the disclosures of which are incorporated herein. Docket 96504.
FIELD OF THE INVENTION
• This invention relates to scanners in general, and in particular to verifying the accuracy of a scanned document.
BACKGROUND OF THE INVENTION
• A document scanner moves a document through a transport path and creates a digital image of the document as it moves. The processor for the document scanner has preset document characteristics and the operator must select functions and features to accommodate the specific requirements for a particular type of document. Alternately, the scanner may default to less efficient settings that will process all documents since scanners are not typically programmed with specific requirements on a document-by-document basis.
• The preset characteristics include document characteristics such as size, weight, texture; and specific application requirements such as resolution and imaging mode, color, simplex, or duplex. In a document scanner, the documents to be scanned may vary by size, weight, color content, physical condition, or other characteristics, which may require different scanner features to be enabled or operator actions to be employed for the most optimal and efficient mode of operation. Prior knowledge of these many different document attributes can enable the proper selection of scanner features to improve the efficiency of the scanning process or enable other features which may provide specific applications required by a particular type, style, or size of document. Prior knowledge of the documents physical condition can also prompt immediate action from the operator to protect the document or scanner or allow other features within the scanner to perform more reliably.
• The exit area of the scanner is used for collecting the scanned documents as they exit the transport. A document must also exit the scanner, once it has been imaged, in an orderly fashion. By discerning document characteristics in the input area as well as the exit area, characteristics such as, but not limited to, number of documents, the exit area features which control stacking and tracking can be managed.
• During the scanning process there are a number of ways in which the information extracted from a scanned document may be inaccurate. The scanned document may be deformed or wrinkled by the document transport system, there may be dust or foreign matter on the image capture optics, the document may be skewed or misaligned, or incorrect scanning features may have been selected, but not limited to, all of which may result in capture of inaccurate information during the scanning process. There exists a need to verify captured image data, especially in high speed document scanners.
• There have been attempts in the document printing industry to verify information on printed images, but the requirements for printing a document are different than the requirements for accurate scanning of a document. For example, U.S. Publication No. 2008/0013848, discloses a line-by-line scan of a printed document to check for defects such as streaks or banding in the printed document. U.S. Publication No. 2003/0076518, discloses a printer which incorporates a CCD raster capture device which images the output tray. The captured output image is compared to data used to print the document.
SUMMARY OF THE INVENTION
• Briefly, according to one aspect of the present invention a document scanner includes verifying accuracy of a raster scanned image of a document by providing an input tray for holding documents prior to imaging; capturing an image of a document in the input tray with an input imaging device; transmitting the captured input tray image to an image processor; transporting the document through a document scanner; capturing a scanned image of the document with a raster capture device; transmitting the raster scanned image to the image processor; and verifying the accuracy of the raster scanned image by comparing the raster scanned image of the document to the input tray image of the document.
• The invention and its objects and advantages will become more apparent in the detailed description of the preferred embodiment presented below.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a cross-sectional view from the side of a transport for a document scanner according to the present invention.
• FIG. 2 is a perspective view of a scanner output tray according to the present invention.
• FIG. 3 is a cross-sectional view from the side of a straight through transport of a document scanner according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
• The present invention will be directed in particular to elements forming part of, or in cooperation more directly with the apparatus in accordance with the present invention. It is to be understood that elements not specifically shown or described may take various forms well known to those skilled in the art.
• FIG. 1 is a side cross-sectional view of adocument scanner10. As shown inFIG. 1,documents20 are first placed in theinput tray30 of thescanner10. The document is moved forward into thescanner10 by theurging roller45, then thefeed roller50 whileadditional documents20 are held back by theseparation roller60. Thedocument20 continues through thedocument transport70, is imaged by the front and rearraster capture devices80 and90 respectively, and then moves out of thetransport exit130 into theoutput tray150.
• As, or after, thedocument20 exits thetransport70 at thetransport exit130, thedocument20 and theoutput tray150 are imaged by theoutput imaging device140. The images are sent to theimage processor100 to discerndocument20 andoutput tray150 characteristics.
• One output tray150 characteristic is whether or not there aredocuments20 present in theoutput tray150. If theoutput tray150 is determined to be empty theprocessor110 will determine howmany documents20 can be scanned before theoutput tray150 becomes full. Also determining theoutput tray150 level of documents will be used by theprocessor110 to stop scanning if theoutput tray150 becomes full. This may happen if the operator continues to placedocuments20 in theinput tray30 while scanning without removing documents (20) from theoutput tray150.
• Another important characteristic is the stacking of thedocuments20 in theoutput tray150. If thedocuments20 are not laying flat, one on top of another, theprocessor110 will stop the scanning process and preventadditional documents20 from stacking improperly. Improper stacking may be an indication of the controlled output stacking120 feature not operating properly or being inadvertently turned off. Based on theoutput tray150 characteristics, proper adjustment of the outputtray side guides160 orend stop170 will be determined. The scanning may be stopped for the operator to adjust theside guides160 orend stop170, or an auto adjust feature can be employed to make the correction while scanning is continued.
• Based on document information from aninput imaging device40 the condition of thedocument20 exiting thescanner10 will be compared to condition ofdocuments20 entering thescanner10 to determine if damage to thedocument20, such as bent or torn corners, is occurring within thedocument transport70, as is shown inFIG. 2. Theprocessor110 will then stop the scanning process and alert the operator.
• Using the information from theinput imaging device40 the number ofdocuments20 entering thedocument scanner10 can be compared to the number ofdocuments20 exiting thescanner10. If the number ofdocuments20 exiting thedocument scanner10 does not match the number ofdocuments20 entering thedocument scanner10 the operator will be alerted to the lostdocument20.
• In a C-shape document transport70 thedocument20 order can be tracked usingdocument20 content captured by theoutput imaging device140 in conjunction with the rearraster capture device90. Indocument scanner11, shown inFIG. 3, having a straight throughdocument transport70, thedocument20 order can be tracked using thedocument20 content captured by theoutput imaging device140 in conjunction with the frontraster capture device80.
• In one embodiment of the invention, an image of adocument20 in aninput tray30 is captured with aninput imaging device40 such as a raster capture device, CCD sensor, or CMOS sensor. The capturedinput tray image190 is transmitted to animage processor100 such as a microprocessor or a computer. The document is then transported through adocument scanner10 which captures a raster scannedimage180 of thedocument20 and the raster scannedimage180 is transmitted to theimage processor100. Theimage processor100 verifies the accuracy of the raster scannedimage180 by comparing the raster scannedimage180 of thedocument20 to theinput tray image190 of thedocument20. If the raster scannedimage180 of thedocument20 does not match theinput tray image190 of thedocument20,scanner10 functions may be modified or other corrective actions taken. Corrective actions may include rotation of the raster capture device, changing a color capture mode, or cleaning image optics.
• Theinput tray image190 of thedocument20 is captured as anarea image210 rather than raster by raster as is typically used to capture the raster scannedimage180 of thedocument20. Theinput tray image190 of thedocument20 may be low resolution or high resolution.
• In another embodiment of the invention, thedocument20 is moved to anoutput tray150 for holdingdocuments20 after it exits thescanner10 and an image of thedocument20 in theoutput tray150 is captured with anoutput imaging device140. The capturedoutput tray150 image is transmitted to theimage processor100 which verifies the accuracy of the raster scannedimage180 by comparing the raster scannedimage180 of thedocument20 to theinput tray image190 of thedocument20 and theoutput tray image200 of thedocument20.
• In yet another embodiment of the invention, an image of adocument20 in aninput tray30 for holdingdocuments20 is captured as anarea image210 rather than raster by raster with aninput imaging device40. Capturing the image as anarea image210 means that an image of theentire document20 is taken rather than imaging thedocument20 raster by raster, which is the usual way of scanning adocument20. The capturedinput tray image190 is transmitted to animage processor100 and thedocument20 is transported to anoutput tray150. After thefirst document20 has been transported out of theinput tray30, an image of asecond document20 in theinput tray30 is captured and transmitted to theimage processor100.
• In a further embodiment, an image of thedocument20 in theoutput tray150 is captured with anoutput imaging device140 and transmitted to theimage processor100. The accuracy of theinput tray30 image is verified by comparing theinput tray image190 of the document to theoutput tray image200 of thedocument20.
• The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the scope of the invention.
PARTS LIST
• 10 document scanner
• 11 document scanner
• 20 documents
• 30 input tray
• 40 input imaging device
• 45 urging roller
• 50 feed roller
• 60 separation roller
• 70 document transport
• 80 front raster capture device
• 90 rear raster capture device
• 100 image processor
• 110 processor
• 120 controlled output stacking
• 130 transport exit
• 140 output imaging device
• 150 output tray
• 160 output tray side guides
• 170 end stop
• 180 raster scanned image
• 190 input tray image
• 200 output tray image
• 210 area image

Claims (8)

1. A method of verifying accuracy of a raster scanned image of a document comprising:

providing an input tray for holding documents prior to imaging;

capturing an image of a document in the input tray with an input imaging device;

transmitting the captured input tray image to an image processor;

transporting the document through a document scanner;

capturing a raster scanned image of the document with a raster capture device;

transmitting the raster scanned image to the image processor; and

verifying the accuracy of the raster scanned image by comparing the raster scanned image of the document to the input tray image of the document.

2. The method as inclaim 1 comprising:

modifying scanner functions if the raster scanned image of the document does not match the input tray image of the document.

3. The method as inclaim 2 wherein the scanner functions are selected from a group consisting of rotation of the raster capture device, changing a color capture mode, or cleaning image optics.

4. The method as inclaim 1 wherein the input tray image of the document is captured as an area image rather than as a raster scanned image.

5. The method as inclaim 1 wherein the input tray image of the document is low resolution.

6. The method as inclaim 1 wherein the input tray image of the document is high resolution.

7. The method as inclaim 1 comprising:

alerting a document scanner operator if the raster scanned image of the document does not match the input tray image of the document.

8. The method as inclaim 1 comprising:

providing an output tray for holding documents after the documents exit the scanner;

capturing an output tray image of the document in the output tray with an output imaging device;

transmitting the captured output tray image to the imaging processor; and

verifying the accuracy of the raster scanned image by comparing the raster scanned image of the document to the input tray image of the document or the output tray image of the document or both.

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