Method of processing a document in an image-based document processing system and an apparatus therefor

An image-based document processing system includes an imaging camera which is disposed along one side of a document transport path. The imaging camera has an acquisition rate associated therewith. A selective illumination array is disposed along the document transport path and generates selective illumination data which is synchronized to the acquisition rate of the imaging camera. A controller is provided for (i) controlling the imaging camera to capture an image of the document as the document is being transported past the imaging camera, and (ii) controlling the imaging camera to capture an image of selective illumination data. The imaging camera may include a charge-coupled device (CCD) having a linear array of sensors. The imaging camera may capture the image of selective illumination data either after the image of the document is captured or before the image of the document is captured. Alternatively, the imaging camera may capture the image of selective illumination data while the image of the document is being captured to provide a composite image of the document and selective illumination data. The selective illumination array may provide light which is transmitted directly towards the imaging camera. Alternatively, the selective illumination array may provide light which is reflected and then transmitted towards the imaging camera.

BACKGROUND OF THE INVENTION
 The present invention relates to image-based document processing systems,
 and is particularly directed to a method of processing a document in an
 image-based document processing system, such as an electronic image-based
 bank check processing system, and an apparatus therefor.
 A typical electronic image-based bank check processing system includes an
 electronic imaging camera having a scan rate which is controlled to
 capture images of documents, such as bank checks, moving past the imaging
 camera along a document feed path. In an image-based bank check processing
 system, it is often desirable to establish quality and/or validity of each
 captured document image before processing the captured document image
 further downstream along the document feed path or archiving the captured
 document image. A known way to establish quality and/or validity of each
 captured document image is to visually inspect each image. However, since
 the number of documents is most often relatively large, visual inspection
 is usually impractical. Another known way to establish quality and/or
 validity of each captured document image is to apply real-time techniques
 in which general illumination parameters or pixel characteristics, for
 examples, are analyzed. However, since these real-time techniques are
 typically based upon statistical methods, many forms of system failure may
 not be immediately identifiable.
 SUMMARY OF THE INVENTION
 In accordance with one aspect of the present invention, an apparatus is
 provided for processing a document transported along a document transport
 path. The apparatus comprises illumination means for generating selective
 illumination data. The apparatus further comprises an imaging camera for
 (i) capturing an image of a document while the document is being
 transported along the document transport path, and (ii) capturing an image
 of selective illumination data. The imaging camera may capture the image
 of the selective illumination data either after the image of the document
 is captured or before the image of the document is captured.
 Alternatively, the imaging camera may capture the image of the
 illumination data while the image of the document is being captured to
 provide a composite image of the document and selective illumination data.
 In accordance with another aspect of the present invention, a method of
 processing a document transported along a document transport path in an
 image-based document processing system including an imaging camera having
 an acquisition rate comprises the steps of (a) capturing an image of a
 document while the document is being transported along the document
 transport path, and (b) capturing an image of selective illumination data
 which is synchronized to the acquisition rate of the camera.
 In accordance with another aspect of the present invention, an apparatus is
 provided for processing a document transported along a document transport
 path. The apparatus comprises an imaging camera having an acquisition rate
 and disposed along the document transport path. Illumination means is
 disposed along the document transport path and is provided for generating
 selective illumination data which is synchronized to the acquisition rate
 of the imaging camera. Control means is provided for controlling the
 illumination means to generate selective illumination data while the
 document is being transported along the document transport path so that
 the imaging camera can capture a composite image of the document and the
 selective illumination data as the document is being transported along the
 document transport path past the imaging camera. The illumination means
 may provide light which is transmitted directly towards the imaging
 camera. Alternatively, the illumination means may provide light which is
 reflected and then transmitted towards the imaging camera.
 In accordance with yet another aspect of the present invention, a method of
 processing a document transported along a document transport path in an
 image-based document processing system including an imaging camera having
 an acquisition rate comprises the steps of (a) generating selective
 illumination data which is synchronized to the acquisition rate of the
 imaging camera, and (b) capturing a composite image of the document and
 the selective illumination data generated in step (a) while the document
 is being transported along the document transport path.
 In accordance with still another aspect of the present invention, an
 image-based document processing system comprises means defining a document
 transport path along which a document can be transported. An imaging
 camera is disposed along one side of the document transport path and has
 an acquisition rate associated therewith. Illumination means is disposed
 along the document transport path and is provided for generating selective
 illumination data which is synchronized to the acquisition rate of the
 imaging camera. Control means is provided for (i) controlling the imaging
 camera to capture an image of the document as the document is being
 transported past the imaging camera, and (ii) controlling the imaging
 camera to capture an image of selective illumination data. The imaging
 camera may capture the image of selective illumination data either after
 the image of the document is captured or before the image of the document
 is captured. Alternatively, the imaging camera may capture the image of
 selective illumination data while the image of the document is being
 captured to provide a composite image of the document and selective
 illumination data.
 In accordance with still another aspect of the present invention, an
 image-based document processing system comprises means defining a document
 transport path along which a document can be transported. An imaging
 camera is disposed along one side of the document transport path and has
 an acquisition rate associated therewith. A selective illumination array
 is disposed along the document transport path and is provided for
 generating selective illumination data which is synchronized to the
 acquisition rate of the imaging camera. A controller is provided for
 controlling the selective illumination array to generate selective
 illumination data such that the imaging camera can capture a composite
 image of the document and the selective illumination data as the document
 is being transported past the imaging camera along the document transport
 path. The imaging camera may be disposed on one side of the document
 transport path and the selective illumination array may be disposed along
 the opposite side of the document transport path facing the imaging
 camera.

DETAILS OF THE INVENTION
 The present invention is directed to a method of processing a document in
 an image-based document processing system and an apparatus therefor. The
 specific construction and use of the image-based document processing
 system may vary. By way of example, an image-based document processing
 system in the form of an electronic image-based bank check processing
 system 10 is illustrated in FIG. 1. The bank check processing system 10
 may be, for example, a sorting machine or a proof machine wherein
 documents such as bank checks are processed in a data processing
 operation.
 As shown in FIG. 1, the bank check processing system 10 has a document
 track which defines a document transport path 11 along which documents,
 such as bank checks, can move. The document transport path 11 has an
 upstream end and a downstream end. The bank check processing system 10
 includes a hopper 12 into which a stack of bank checks (not shown) are
 placed. A document feeder 13 adjacent the hopper 12 selectively feeds or
 drives each check from the stack of bank checks in the hopper to transport
 the check from the upstream end to the downstream end along the document
 transport path 11 to sorting bins 26 located at the end of the document
 transport path.
 The bank check processing system 10 further includes a MICR reader 16 which
 reads a MICR codeline from each bank check being processed in a known
 manner. An OCR reader may be used in place of the MICR reader 16 depending
 upon on the particular application. An encoder 18 encodes any missing
 fields on each check. An endorser 20 applies an endorsement in a known
 manner to the checks. A bank stamp 22 stamps each check to identify the
 bank institution processing the check. The structure and operation of MICR
 readers, OCR readers, encoders, endorsers, and bank stamps are well known
 and, therefore, will not be described.
 Referring to FIGS. 1 and 2, the bank check processing system 10 further
 includes an image capture subsystem 50 located along the document
 transport path 11. The image capture subsystem 50 captures an image of
 each check for the purpose of establishing quality and/or validating data
 associated with the check and/or to archive the image of the check.
 As shown in FIG. 2, the image capture subsystem 50 includes a number of
 lamps 40 located on one side of the document transport path 11. The lamps
 40 provide light which illuminates a bank check 30 which is being
 transported from the upstream end of the document transport path 11
 towards the downstream end of the document transport path. Light from the
 lamps 40 is reflected from the check 30 to provide an image of the check.
 The image capture subsystem 50 further includes an electronic imaging
 camera 52 which is located along the same side of the document transport
 path 11 as the lamps 40. The camera 52 includes an optical system 53
 having a number of lenses through which the image of the check 30 is
 magnified to provide a magnified image of the check. The magnified image
 may be either a reduction or an enlargement of the check 30. The camera 52
 may include a charge-coupled device (CCD) or other suitable element having
 a linear array of sensors which scan the magnified image of the check 30.
 A trigger sensor 14 is located along the document transport path 11
 upstream of the camera 52. The trigger sensor 14 provides a trigger signal
 when the leading edge of the check 30 moving along the document transport
 path 11 moves past the trigger sensor. Accordingly, the trigger sensor 14
 provides a trigger signal when the leading edge of the check 30 moving
 along the document transport path 11 is about to move in front of the
 camera 52.
 As the check 30 moves in front of the camera 52 and continues to move past
 the camera towards the downstream end of the document transport path 11,
 the camera captures the image of the check 30. More specifically, as the
 check 30 moves past the camera 52, the camera may generate successive scan
 lines of pixels to produce a matrix of pixels associated with the check.
 Each pixel is usually represented by gray scale image data in which a
 particular gray level is associated with the pixel. For example, each
 pixel may have any one of 256 gray levels associated therewith, ranging
 from completely black (level zero) to completely white (level 255).
 Alternatively, the camera 52 may be of the type which captures color image
 data associated with the check 30.
 In accordance with the present invention, the image capture subsystem 50
 further includes a selective illumination array 64 which is located along
 one side of the document transport path 11 facing opposite the optical
 system 53 of the camera 52, as shown in FIG. 1. As shown in FIG. 3, the
 illumination array 30 includes a number of light emitting diodes (LEDs) 66
 which are aligned vertically to form a vertical array. The actual size of
 each of the LEDs 66 is smaller than as shown in FIG. 3. However, for
 purposes of illustration, the size of each of the LEDs 66 is shown
 exaggerated (i.e., larger) in FIG. 3. It is contemplated that the
 illumination array 64 may include any number of LEDs which are vertically
 aligned.
 The image capture subsystem 50 further includes an illumination controller
 56 which communicates via line 61 with a program memory 60. The controller
 56 also monitors the trigger sensor 14 for the presence of a trigger
 signal. The camera 52 provides image data on line 55 which is stored in an
 image data memory 58 to provide a stored digitized image of the check 30.
 The camera 52 also provides a scan rate signal on line 65 which is
 monitored by the controller 56. The controller 56 reads image data on line
 59 from the image data memory 58 and compares this image data with
 predetermined image data which is stored in the program memory 60 to
 provide a basis upon which image system integrity may be analyzed. For
 example, proper magnification of the optical system 53 of the camera 52,
 unobstructed clarity of the optical system of the camera, or focus of the
 optical system of the camera, may be analyzed.
 In particular, the controller 56 may include a microcomputer which
 communicates with the program memory 60. Suitable microcomputers and
 memories are readily available in the marketplace. Their structure and
 operation are well known and, therefore, will not be described.
 Alternatively, the controller 56 may include dedicated hardware circuitry
 for the particular application desired.
 The controller 56 may also monitor output signals from certain components,
 such as the MICR reader 16, the encoder 18, the endorser 20, and/or the
 bank stamp 22, disposed along the document transport path 11. Information
 from these components is utilized in accordance with a number of control
 programs stored in the program memory 60.
 As already mentioned hereinabove, the trigger sensor 14 provides a trigger
 signal when the leading edge of the check 30 moves past the trigger
 sensor, as shown in FIGS. 2 and 3. The controller 56 monitors the trigger
 sensor 14 for presence of a trigger signal, and provides a control signal
 on line 63 to control operation of the illumination array 64. The
 controller 56 precisely synchronizes the control signal on line 63 to the
 acquisition rate of the camera 52 as monitored on line 65. The camera 52
 captures an image of the check 30 as the check continues moving downstream
 along the document transport path 11 past the camera 52, such as shown in
 FIG. 4. The camera 52 continues capturing the image of the check 30 until
 the trailing edge of the check has moved past the camera, such as shown in
 FIG. 5. A complete captured image of the check 30 is shown in FIG. 6.
 After the trailing edge of the check 30 has moved past the camera 52, as
 shown in FIG. 5, the controller 56 controls the selective illumination
 array 64 to sequence the array of LEDs 66 in synchronization with the
 acquisition rate of the camera 52, so as to provide a precise optical test
 pattern/sequence which is also captured as an image by the camera 52. The
 precise optical test pattern/sequence may be one of a number of known
 expected patterns/sequences which is distinct from the ambient
 illumination from the lamps 40. The particular optical test
 pattern/sequence provided depends upon the particular control program
 stored in the program memory 60 which the controller 56 executes.
 Examples of optical test patterns provided by the LEDs 66 are illustrated
 in FIGS. 7A and 7B. The optical test pattern of FIG. 7A may be used to
 verify that all pixels associated with the camera 52 have responded
 correctly to ON and OFF states. Any grease, ink, or other translucent
 contaminants on the optical system 53 of the camera 52 would tend to
 refract illumination from adjacent pixels. Such a condition of the optical
 system 53 of the camera 52 may be detected by comparing the test pattern
 of FIG. 7A as captured in the image data memory 58, with predetermined
 image data or parameters stored in program memory 60, for example.
 The optical test pattern of FIG. 7B may be used to verify that the
 magnification factor associated with the optical system 53 of the camera
 52 is correct. This verification is accomplished by counting relative
 pixel positions of illuminated areas as captured in the image data memory
 58, and comparing this count to predetermined target values stored in the
 program memory 60, for example. The pattern of FIG. 7B may also be used to
 determine vertical position of the camera 52 relative to a known position
 of the selective illumination array 64 so that vertical height adjustment
 of the camera can be made. The vertical height adjustment of the camera 52
 may be made either in real-time or during initial set-up. The pattern of
 FIG. 7B may also be used to verify proper focus of the optical system 53
 of the camera 52.
 The optical test sequence of FIG. 7C may be used to determine the extent of
 usable field of view for a particular magnification factor of the camera
 52. The optical test sequence of FIG. 7C may also be used to determine
 magnification linearity across the entire field of view of the camera 52
 by comparing apparent changes in adjacent pixel positions. Further, the
 optical test sequence of FIG. 7C may be used to determine sensitivity
 response of the camera 52 to single and/or multiple illumination points.
 It should be apparent that an optical test pattern/sequence, such as shown
 in FIGS. 7A, 7B, or 7C, is generated and captured as an image by the
 camera 52 between adjacent checks moving along the document transport path
 11. The image of the optical test pattern/sequence is generated and
 captured for a number of different purposes as already described
 hereinabove.
 It is contemplated that the LEDs 66 of the illumination array 64 may also
 be controlled to provide typical embedded information in a captured image
 of a check as the check is moving past the camera 52 to provide a
 composite image of the check and the embedded information. Such a
 composite image of a check and embedded information is shown in FIG. 8.
 When the composite image such as shown in FIG. 8 is generated, the
 controller 56 obtains information from other sources, such as the MICR
 reader 16, to control operation of the illumination array 64. In this
 case, the controller 56 need not analyze the captured image data from the
 image data memory 58, but only control operation of the illumination array
 64. The composite image may contain information along a leading edge, a
 top edge, a bottom edge, and a trailing edge of the image.
 For example, the leading edge of the composite image may contain an item
 batch and consecutive document identification number, as shown in FIG. 8.
 The top edge of the composite image may contain date and time of item
 capture, as shown in FIG. 8. Alternatively, the top edge of the composite
 image may contain information associated with name and location of the
 processing center, or information associated with identification of the
 image capture subsystem 50. The bottom edge of the composite image may
 contain codeline information associated with the check 30, such as shown
 in FIG. 8. The trailing edge of the composite image may contain security
 information in machine-readable format, for example. The machine-readable
 format may be in either dot or barcode, for examples. Alternatively, the
 trailing edge of the composite image may contain an image authentication
 code, codeline data associated with the check, an image file name, and/or
 parameters associated with the ambient illumination provided for the
 camera 52 by the lamps 40. For example, these parameters may indicate
 whether ultraviolet, infrared, or visible light is being used to
 illuminate items moving before the camera 52 along the document transport
 path 11.
 Although the above describes the selective illumination array 64 as being
 located directly across the document transport path 11 from the camera 52
 to transmit light directly into the optical system 53 of the camera, it is
 contemplated that a selective illumination array may be located on the
 same side of the document transport path 11 with the camera such that
 light is initially directed towards the item and then reflected from the
 item towards the optical system of the camera.
 It is contemplated that the camera 52 may be of a type which is different
 from the type described hereinabove. For example, the camera 52 may
 include a CCD or other suitable element having an area array of sensors
 instead of a linear array of sensors. If an area array of sensors is used,
 then a frame rate would be associated therewith instead of a scan rate
 which is more particularly associated with a linear array of sensors. The
 scan rate of a camera or the frame rate of a camera may be referred to as
 an acquisition rate associated with the particular type of camera. Also,
 if an area array of sensors is used, then a two-dimensional illumination
 array may be used in place of the previously described selective
 illumination array 64 which is vertically aligned in one dimension.
 It is also contemplated that selective illumination data may be generated
 using other sources. For example, a remotely mounted assembly having
 suitable fiber optical conduits which direct selective illumination data
 to the camera 52 may be used. Alternatively, a remotely mounted assembly
 having a scanning laser source which directs selective illumination data
 to the camera 52 may be used.
 A number of advantages result by processing documents such as bank checks
 in accordance with the present invention as just described hereinabove.
 One advantage is that process diagnostics for the camera 52 and related
 optical components is enhanced and simplified. Another advantage is that a
 significantly greater level of confidence is provided about the quality
 and/or validity of captured item images. Still another advantage is that
 data integrity and image security are maintained when parametric
 information associated with the particular check is embedded in a
 composite image, such as the composite image of the check 30 and embedded
 information shown in FIG. 8.
 From the above description of the invention, those skilled in the art to
 which the present invention relates will perceive improvements, changes
 and modifications. Numerous substitutions and modifications can be
 undertaken without departing from the true spirit and scope of the
 invention. Such improvements, changes and modifications within the skill
 of the art to which the present invention relates are intended to be
 covered by the appended claims.