Abstract:
A method of locating a check image region within a document image comprising the steps of locating a MICR region of the check and calculating the top of the check relative to the MICR region.

Description:
PRIORITY CLAIM 
     This application claims benefit of U.S. Provisional Application Ser. No. 61/087,811 filed Aug. 11, 2008 entitled “Automated Check Detection and Imaging Cropping.” 
    
    
     FIELD OF INVENTION 
     This invention relates to document image processing, and specifically, to automatically detecting and cropping a bank check region of an image. 
     BACKGROUND OF THE INVENTION 
     Existing check reader recognition technologies assume that the image being processed is only the image of the check with no extraneous information. These technologies typically work with specialized check scanners and rely heavily upon a mailroom preparation process where the check portion of the paper is removed form the rest of the paper document. Companies that wish to scan the entire paper document, keeping it intact are currently unable to use these recognition technologies. 
     A technology is needed to automatically locate the check image within the entire paper document and use the resulting check image or its coordinates with existing check reader recognition technologies. This will enable companies to keep their paper documents intact, therefore bypassing the mailroom preparation process. 
     SUMMARY OF INVENTION 
     This invention automatically locates the check image within the entire paper document image. The check is located in a two step process. First the bottom of the check (MICR region) is identified. Magnetic Ink Character Recognition (MICR) is a character recognition technology utilized primarily by the banking industry to facilitate the processing of checks. The process was shown to the American Bankers Association in 1956, and employed in the U.S. by 1963 almost universally. On Sep. 12, 1961, Stanford Research Institute (now SRI International) was awarded U.S. Pat. No. 3,000,000 for the invention of MICR, the disclosure of which is incorporated herein by reference. 
     Relative to lower MICR area, the top of the check is then located. Optionally, the resulting area can be used to write out a new image that will contain only the check portion of the document. The resulting check image can subsequently be used with existing check reader recognition technologies keeping the original paper document intact. Alternatively, the coordinates of the check area can be communicated to the check recognition engine. 
     An embodiment of the invention includes a method of resolving a check image region within a document image comprising the steps of processing by optical character recognition (OCR) a full page document image containing rows of text. The OCR is applied using a MICR-specific font so that non-MICR fonts return a higher level of OCR exceptions than MICR fonts in the document image. The level of OCR exceptions for each row of text in the document image is calculated using the presumption that alternate fonts such as Arial or Times New Roman will generate more OCR exceptions since the OCR process is specifically looking for MICR font characters. 
     The location of the row of text most likely to contain the MICR data is resolved based on the level of OCR exceptions. The lower boundary of the check image region is defined by the location of the MICR data. 
     The next step is that of establishing a check top candidate area. The check top candidate area is defined by a collection of variations in height of predefined check dimensions measured from the location of the MICR data. Standard checks typically vary in height between 2.5 and 3.5 inches. A horizontal raster line is detected within the check top candidate area whereby the horizontal raster line defines the top of the check. Line detection by OCR processing is well known as described in U.S. Pat. No. 4,949,392, the specification of which is incorporated herein by reference. An upper boundary of the check image region is thus defined by the location of the horizontal line. Finally, the full page document image is digitally cropped above the upper boundary and below the lower boundary to transform the full page document image to a check-specific image. This check-specific image may be saved to a new image file. 
     There may be instances wherein a plurality of horizontal lines exists within the check top candidate area. In such instances, the upper boundary of the check image region is defined by the location of the horizontal raster line that is closest to a standard check size. In a condition of uncertainty, the line farthest from the lower boundary is selected. This approach may occasionally lead to a larger cropped image but it forgoes the danger of too aggressively cropping out substantive information on the check. 
     There may also be instances wherein an absence of detectable horizontal raster lines exists. In those instances, the tallest check height dimension is selected from the collection to define the upper boundary. 
     An embodiment of the invention is also disclosed in the form of a computer-readable media having computer-executable instructions for performing a method of running a software program on a computer. An example of such software includes that sold under the brand INIFIWORX manufactured by AnyDoc Software based in Tampa, Fla. This embodiment includes one or more computer-readable media having computer-executable instructions for performing a method of running a software program on a computer, the computer operating under an operating system, the method including issuing instructions from the software program comprising the steps of processing by OCR a full page document image containing rows of text using a MICR-specific font wherein non-MICR fonts return a higher level of OCR exceptions than MICR fonts in the document image, calculating the level of OCR exceptions for each row of text in the document image, resolving the location of the row of text most likely to contain the MICR data based on the level of OCR exceptions, defining a lower boundary of the check image region by the location of the MICR data, establishing a check top candidate area, the check top candidate area defined by a collection of variations in height of predefined check dimensions measured from the location of the MICR data, detecting a horizontal raster line within the check top candidate area whereby the horizontal raster line defines the top of the check, defining an upper boundary of the check image region by the location of the horizontal line and digitally cropping the full page document image above the upper boundary and cropping the full page document image below the lower boundary to transform the full page document image to a check-specific image. 
     It should be understood that this invention may be deployed on a wide variety of operating systems and computer platforms ranging from personal computers to mainframe systems. Within the field of document management, it is well known to batch process a large number of images at a time under an automated framework. Full page document images may be scanned prior to implementing this process or may have been computer-generated and never existed as hardcopy. 
     An advantage of the current invention is that MICR data is near-universal for modern checks and therefore originating check locations with a universal constant provides, in turn, a universal solution for check detection that accommodates a wide variety of check format diversity. 
     Another advantage of the current invention is that variable check heights may be accommodating by detecting a horizontal raster line associated with the top of the check. This permits more precise check cropping thus improve framing and accentuate subject matter for subsequent analysis, transmission and/or archiving. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a fuller understanding of the invention, reference should be made to the following detailed description, taken in connection with the accompanying drawings, in which: 
         FIG. 1  shows a payment stub and check separated by a perforated tear line. 
         FIG. 2  shows a computer screen display of a digitally imaged check and payment stub. 
         FIG. 3  shows a computer screen display of a MICR font-specific OCR process applied to the digitally imaged check and payment stub. 
         FIG. 4  shows a computer screen display illustrating an embodiment of the invention to determine the location of the top of the check relative to the MICR region. 
         FIG. 5  shows a computer screen display illustrating an embodiment of the invention whereby non-check areas of the digital document image are cropped out. 
         FIG. 6  shows a computer screen display illustrating an embodiment of the invention showing the extracted check image as a separate, new image file. 
         FIG. 7  is a diagrammatic illustration of an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The fundamental process of the present invention may be encompassed in two steps. The first step in locating the check image involves finding the bottom of the check. For this to be done accurately, the MICR line must be located. To accomplish this, full page OCR is performed on the image using a MICR only font. MICR has been almost universally adopted by the banking industry to facilitate the processing of checks. Almost all checks in the United States and United Kingdom include MICR characters at the bottom of the paper in a font known as E-13B. 
     Most of the OCR data returned is erroneous since the image mostly contains non-MICR information. The resulting OCR results are then analyzed to determine which row of text contains the actual MICR data. A voting algorithm is used that weights the ASCII data row with the most characters and the highest confidence values as returned by the OCR engine. 
     The second step of the process involves locating the top of the check. This is accomplished by using technology that locates horizontal raster lines of the image. As with most check documents, many horizontal lines may be discovered. Since check sizes are standardized (between 2.5 and 3.5 inches) the line that relates closest to these standard sizes is chosen with a bias towards the larger check. In such instances, the upper boundary of the check image region is defined by the location of the horizontal raster line that is closest to a standard check size. In a condition of uncertainty, the line farthest from the lower boundary is selected. The reasoning behind this is to preserve the check image in case the wrong line is chosen. In the case where no lines are located, the invention defaults to the larger check size. 
     Turning to  FIG. 1 , full page document image  10  is either generated electronically or scanned from a hardcopy using an optical scanner. Document image  10  includes check stub  20 , check section  30  having a MICR region  40 , and perforation  50  to detach check section  30  from check stub  20 . In one application of the present invention, thousands of remittance checks such as those paid by distributors to a manufacturer are received and scanned in as a batch process. However, each distributor may use a different check style, font and/or layout. The manufacturer wants to store images of only the check and not the check stub or ancillary data. Additionally, the manufacturer may want to run OCR on the check only in a downstream process to monitor remittances for its billing system. For all these reasons and more, it is desirable to improve framing, accentuate subject matter and/or change aspect ratio of full page document image  10 . 
     In  FIG. 2 , computer display  60  shows a visual representation of document image  10  for illustrative purposes only. OCR execution button  70  is shown, again, for demonstrative purposes as a commercial embodiment of the present invention would include the option to automate the batch processing of a plurality of document images without requiring user interaction. In  FIG. 3 , each row of text in document image  10  is processed by OCR for a MICR font. As shown for illustrative purposes, fourteen (14) rows generated exceptions denoted with an “x.” while the last row detected a valid MICR font denoted with a check box. The Cartesian coordinates of the last row defines the lower boundary of the check. The next step is to determine the upper boundary of the check. 
     In  FIG. 4 , MICR text  80  defines lower boundary  90  of the check image. Check top candidate area  100  is defined by a collection of variations in height of a predefined check dimensions measured from lower boundary  90 . Small check size height  110  establishes the lower edge of check top candidate area  100 . Large check size height  120  establishes the upper edge of check top candidate area  100 . Within check top candidate area  100  exists first horizontal line  130  and second horizontal line  140 . Third horizontal line  150  constitutes the lower portion of the check stub but would be ineligible to define the upper boundary of the check as it is located outside of check top candidate area  100 . 
     In an embodiment of the invention, the horizontal line most distant from lower boundary  90  and existing within check top candidate area  100  defines an upper boundary of the check image region. This helps mitigate the possibility that the check image would be too tightly cropped and thus exclude information later required. In this example, second horizontal line  140  would define the upper boundary of the check image region. In the event that no horizontal line was detected, the upper edge of check top candidate area  100  calculated from large check size height  120  becomes the default upper boundary of the check image region. Horizontal lines are detected by pel pattern techniques as known in the art. 
       FIG. 5  shows check section  30  extracted from the cropped area above and below check section  30 .  FIG. 6  shows computer display  60  displaying check section  30  as a separate image file. 
       FIG. 7  shows the steps to an embodiment of the invention including retrieving a full page document image  160  having a check image continued therein. The document image is OCR processed  170  for MICR fonts. Non-MICR fonts generate exceptions as they are not well-resolved by the OCR settings. MICR fonts, by contrast, are more easily identified to resolve MICR location  180 . Thus, the lower boundary of the check image region is defined by the location of the MICR data. Horizontal line detection  190  is applied to an area above the lower boundary, the area defined by the various possible check heights expected. Horizontal lines within that candidate area are used to resolve the upper boundary of the check image region. When a plurality of horizontal lines are encountered, the line most distant from the lower boundary is selected. When no horizontal lines are detected, the largest anticipated check size is used to define the upper boundary. The check image is digitally cropped  210  from the rest of the document image and a new check image file  220  is generated for transmittal, analysis and/or archiving. 
     It will be seen that the advantages set forth above, and those made apparent from the foregoing description, are efficiently attained and since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matters contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 
     It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween. Now that the invention has been described,