Abstract:
A method and system for verifying a two dimensional mark without the need to transfer an image between a verification system having a data collector and host software connected to a display, the method comprising the steps of displaying a blank background image corresponding to the data collector field of view on the display, using the data collector to scan for a code at least in part within the field of view, identifying an item that may correspond to a code, graphically representing the identified item on the display in a location corresponding to the actual location within the field of view, monitoring the position of the identified item, attempting to verify the code when the identified item is at an aligned position, and indicating that the code has been verified. In one embodiment, an image of the code only may be displayed and/or transferred to the host software.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Not applicable. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       BACKGROUND OF THE INVENTION 
       [0003]    The present invention relates to mark verification systems in secure environments and more specifically to a method of correctly positioning an item marked with a two dimensional code, e.g., a Data Matrix code, or arranging a code reader associated with the verification system without showing or acquiring an image from the field of view of the code reader. 
         [0004]    Many different industries require that some form of identification mark be applied to manufactured components so that the components may be tracked during distribution, when installed or assembled, during maintenance processes, during use, and after use. For instance, in the jet engine industry, jet engines include, among other components, turbines that include turbine blades that are manufactured in various size lots. Each turbine blade is marked when manufactured so that the blade may be tracked. If a defect is ever detected in the blade, the defect can be traced back to a specific lot and manufacturing process associated therewith so that possible defects in other blades from the same lot can be identified. Furthermore, the maintenance history of specific components can be tracked to identify positive or negative characteristics of specific materials and/or processes used to produce the components. Marks that are applied directly to components or parts are generally referred to as direct part marks (DPMs). 
         [0005]    To directly mark components, known marking systems have been developed that include a marking station to apply a mark to each component. For instance, in at least some known cases, a marking station will apply a Data Matrix barcode symbol, i.e., a two-dimensional barcode that stores from 1 to 2,335 alphanumeric characters, to each manufactured component. An exemplary Data Matrix symbol is typically square and can range from 0.001 inch per side up to 14 inches per side. 
         [0006]    Despite attempts to apply marks that can be read consistently thereafter, mark application errors occur such that the mark cannot be subsequently consistently read and decoded properly. To verify that applied marks are of sufficient quality to be read by code readers, marking systems often include, in addition to the aforementioned marking station, a verification station and at least a portion of a transfer line to transfer components from the marking station to the verification station. After a mark is applied to a component, the component is transferred to the verification station where the mark must be precisely aligned with a light source and a camera/mark reader. The verification station may be stationary, wherein the station is juxtaposed such that the camera, or reader, field of view is aligned with a location through which the component will pass. 
         [0007]    The verification station may include stationary mechanisms (e.g., mechanical locking devices, sensors, etc.) for aligning the component with the light source and camera such that the mark is optimally presented. Upon proper positioning, the camera or reader can capture an image of the mark and a host system processor can analyze mark verifying information from the mark. Alternatively, the verification station may include a handheld code reader or other portable camera device for obtaining the mark images to be analyzed. 
         [0008]    While marking and verification systems of the above kind work well to verify component mark quality, such systems have a number of shortcomings. A number of these shortcomings result from the potentially unregulated use of cameras and image capture devices in secure facilities. Standard verification systems contain a camera that takes and stores pictures of an entire camera or verifier field of view. The field of view is not limited to just a code but typically includes a signification portion of a marked component. Even worse, in the case of verification station with a handheld reader or a handheld reader generally, the reader can be moved such that the available field of view includes anything within a secure facility. Furthermore, due to its portable nature, a handheld reader can be moved to other remote areas away from intended usage areas. 
         [0009]    This creates the potential for unauthorized data acquisition, i.e., industrial espionage, by permitting the taking and storing of pictures for later retrieval. This in turn has kept standard verification systems and handheld code readers with image acquisition capabilities from being used in certain applications. Unauthorized images could be strategically used by competitors to anticipate future developments, acquire trade secrets including specific equipment used, manufacturing specifics, or even record the identities of specific personnel. 
         [0010]    This potential is even more of an issue in secure and/or classified production environments such as are found in government research and testing facilities, military bases, military contractor production facilities, and the like. Many of these facilities could benefit by using DPMs, but due to the restrictions on cameras, cannot use standard verification systems. 
         [0011]    One known solution to this problem is to never shown an image of the field of view, and thus the code, nor let any images be recorded in the memory of the verification system. This solution is less than ideal because users generally prefer to be able to see an image of a code immediately after a successful verification or read attempt. Furthermore, the ability to see the reader field of view facilitates setting up a verification or reader station and improves the scan speed when using a handheld reader. The lack of real-time images results in a lack of information presented to the user and may cause unneeded re-work or waste due to the inability to read an otherwise acceptable mark. 
         [0012]    These and other objects and advantages of the invention will be apparent from the description that follows and from the drawings which illustrate embodiments of the invention, and which are incorporated herein by reference. 
       BRIEF SUMMARY OF THE INVENTION 
       [0013]    An illustrative embodiment of the present invention provides a method for aligning a code reader with a code to be read or imaged, without displaying an image of items within the field of view of the reader. The method includes the steps of providing a blank background image on a display corresponding to a data collector field of view, scanning for a code at least partially contained within the field of view, identifying an item that may correspond to a code, and graphically representing the identified item in the blank background image in a location corresponding to the actual location of the identified item within the field of view. Further steps of this method may include defining at least one desired code position, graphically presenting the desired position on the blank background corresponding to the actual location of the desired position, monitoring the position of the identified item to ascertain when the identified item is in the desired position, providing an indication when the item is at the desired position and/or has been verified. 
         [0014]    In some cases the step of graphically representing the identified item on the blank background includes presenting a colored rectilinear boundary line, i.e., box, that circumscribes the outline of the identified item without showing an image of the identified item. Also, the step of graphically presenting the desired position on the blank background may include presenting a rectilinear shape in a second color corresponding to the desired code location. 
         [0015]    In a further embodiment, the box representing the code changes position and/or size in response to either movement of the reader or movement of the code. The box representing the code may also change color in response to the code: being properly aligned within the field of view, being at an acceptable angle in relation to the reader, and having acceptable perspective distortion. 
         [0016]    In a further embodiment, when the field of view of the data collector is aligned along a central axis and the code to be scanned is formed on a substrate surface, the method further includes the steps of identifying the angle of the central axis to the substrate surface and providing an indication of the angle between the central axis and the substrate surface. The method may further include providing an indication when the angle is within an acceptable range. 
         [0017]    In a further embodiment, further steps include obtaining data corresponding to the identified item and attempting to decode the identified item. If the identified item is successfully decoded and verified, the box representing the identified item is replaced with an image of the code. The code image may be a generated image corresponding to the code wherein the presented code image includes substantially no data from other portions of the field of view. The code image may include cropping the image corresponding to the field of view down to a size substantially corresponding to the code. 
         [0018]    In a further embodiment, the reader is a hand held reader and the display is on the hand held reader wherein the blank background and generated code image is presented via the hand held reader display. 
         [0019]    In a still further embodiment, an apparatus for obtaining an image limited to a code within an environment comprises: a code reader having a display and a data collector that obtains an image of a field of view, a processor that receives and examines the image of the field of view to identify an item that may correspond to a code; and a display driver that controls information presented via the display. A blank background image is initially shown on the display corresponding to the data collector field of view. A graphical representation of the identified item is also displayed on the blank background corresponding to the actual location of the identified item. At least one desired, or aligned, position for a code within the data collector field of view is defined. The processor monitors the position of the identified item within the field of view to ascertain when the identified item is in the aligned position and indicates via the display when the identified item is in the aligned position. 
         [0020]    In an alternative embodiment, an apparatus for generating an image of a code without generating images of other objects within an environment comprises: a code reader having a display and a data collector that obtains an image of a field of view, and a processor that receives and examines the image to identify an item that is at least in part within the field of view and may correspond to a code. The portion of the field of view corresponding to the identified item is a considered a possible code portion of the field of view while the other portions of the field of view are considered background portions of the field of view. After the processor verifies that the identified item is a code, a code image corresponding to the verified code is generated wherein the code image includes substantially no data from the background portions of the field of view. The apparatus further includes a display driver presenting the code image via the display. 
         [0021]    In some cases, the processor may verify that the identified item is a code by successfully decoding the identified item. Thereafter, the processor generates a code image corresponding to the verified code by cropping the image corresponding to the field of view down to a size substantially corresponding to the verified code. 
         [0022]    To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described. The following description and the annexed drawings set forth in detail certain illustrative aspects of the invention. However, these aspects are indicative of but a few of the various ways in which the principles of the invention can be employed. Other aspects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0023]      FIG. 1  is a schematic view illustrating exemplary hand held reader including a display that is consistent with at least some aspects of the invention; 
           [0024]      FIG. 2  is a schematic illustrating components of the reader of  FIG. 1 ; 
           [0025]      FIG. 3  is a flowchart illustrating at least one method that may be performed by the processor of  FIG. 1  to identify and locate a mark; 
           [0026]      FIGS. 4A-E  are illustrations simulating a potential sequence of displays generated by the reader of  FIG. 1 ; 
           [0027]      FIG. 5  is a subprocess that may be added to the process of  FIG. 3 ; and 
           [0028]      FIG. 6  is a schematic similar to  FIG. 1 , albeit illustrating a second system configuration. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0029]    Referring now to the drawings wherein like reference numerals correspond to similar elements throughout the several views and, more specifically, referring to  FIG. 1 , one inventive embodiment will be described in a context of an exemplary handheld code reader  15  that can be used to obtain images of a mark/code  28  that appears on a surface  24  of a marked item  22 . In  FIG. 1 , reader  15  includes a camera  13  (see also  FIG. 2 ) (e.g., a CCD area or other type) mounted within a generally pistol shaped device housing  17  that includes a handle portion  19  and a barrel portion  21 . The camera  13  is arranged in barrel portion  21  so that a field of view (FOV)  30  fans out over an area adjacent a distal edge of the barrel portion  21 . A display  40  is mounted at the top end of handle position  19 . 
         [0030]    Referring also to  FIG. 2 , reader components inside housing  17  include a processor  23 , a memory  25 , and a light source  27 , where processor  23  is linked to camera  13 , light source  27 , memory  25  and display  40 . Processor  23  runs software programs stored in memory  25  to perform various inventive functions. In addition, processor  23  controls light source  27  to illuminate surfaces on which marks  28  are applied as well as camera  13 . 
         [0031]    In one embodiment, the image of the mark  28  is processed to verify that the mark  28  is of sufficient quality to be used by subsequent mark readers, e.g., at a customer&#39;s facility. To perform the verification process, reader  15  is linked to a host system (not shown) running a verification application. The verification application may be a commercially available software-based direct part mark verification program. Preferred features of such an application include the ability to log, report and communicate verification results, images and information about system set-up, record the overall score and quality metrics for each mark that is verified, time and date-stamp each verification, and store bitmaps of each mark image. A preferred verification application further provides a simple and intuitive graphical user interface (GUI) via a display, or monitor,  106  (see  FIG. 6 ) enabling a user to enter set-up information and see the verification results (e.g., whether or not the quality of the imaged mark meets or exceeds a baseline quality assessment value). 
         [0032]    Referring now to  FIG. 3 , an exemplary method  60  that is consistent with at least some inventive embodiments is illustrated. Referring also to  FIGS. 1 and 4 , at process block  62  after reader  15  has been enabled by a user, a blank background image or screen  42  is presented on the display  40 . The blank screen  42  represents and corresponds to the field of view  26  of camera  13 . 
         [0033]    To prevent unauthorized image acquisition, screen  42  does not, at least initially, display any actual images from the field of view  26  acquired by camera  13 . Instead, display  40  presents blank screen  42  wherein any identified items of interest (e.g., unverified codes  28 ), are presented as graphical illustrations on the blank background. 
         [0034]    At step  64 , reader  15  continuously scans for codes or marks  28  at least in part within the field of view  26 . As shown in step  66 , when reader  15  identifies an item that may correspond with a code  28  at least partially within the field of view  26 , the size and location (i.e., the boundary coordinates of the item) relative to the field of view  26  are determined. At block  68 , processor  23  graphically presents the identified item at a location within the screen  42  that corresponds to the physical location of the identified item within the field of view  26 . To this end, see exemplary box  46  (hereafter “the code representation”) in  FIG. 4B  that is a graphical representation of an item in the field of view that has characteristics indicative of a code of mark to be read. 
         [0035]    In addition to arranging the camera  13  and/or mark  28  such that the mark  28  is at least in part in the aligned position of the field of view  26 , a user may also need to satisfy other pre-determined parameters, such as suitably arranging the mark  28  in order to enable the reader  15  to obtain an image of sufficient quality to perform a decoding process. Other than code position, parameters required for obtaining a suitable image may include an angle of the reader  15  relative to the code  28 , the amount of perspective distortion of the mark  28 , reader focus, etc. In an embodiment not shown, when the field of view  26  of the camera  15  is aligned along a central axis and the mark  28  to be scanned is formed on a substrate surface, the angle between the central axis and the surface is identified and indicated to a user, including when the angle is within an acceptable range. 
         [0036]    Referring still to  FIG. 3 , code-field of view alignment is monitored by processor  23  at decision block  82 . Here, alignment is determined by obtaining images of the code, identifying code characteristics and comparing those characteristics to known suitable code characteristics at block  83 , when a code is suitably aligned within the reader field of view, suitable alignment is indicated. In at least some embodiments suitable alignment may be indicated by changing the color of the code representation  46  (see again  FIG. 4B ) from, for instance, red (indicating misalignment) to green (indicating alignment). In other cases, alignment may be indicated by flashing the representation  46  on and off or by illuminating an LED (see  29  in  FIG. 1 ) or the like as activating an audible speaker (see  31  in  FIG. 1 ) mounted to the reader housing  17 . 
         [0037]    In step  84 , after the code  28  and reader  15  are correctly positioned, data or an image corresponding to the identified item is obtained. Reader  15  attempts to de-code the identified item using known decoding software. Where decoding is successful, processor  23  may indicate a successful image capture and decoding process via display  40  or in any other suitable manner (e.g., an LED  29 , an audible indication via speaker  31 , etc.). In other cases, processor  23  may be programmed to crop the image of the code and present only the image of the code via display  40  in a large format  48  as shown in  FIG. 4E . In some embodiments the cropped image may include a small quiet zone around the code/mark. In other embodiments processor  23  may be programmed to present just the image of the code  48  on the blank background  42  instead of the box type and code representation  46  as in  FIG. 4F . In still other embodiments, instead of presenting an actual image of the de-coded code, processor  23  may be programmed to synthesize a rendition of the decoded code using the decoded information and the synthesized rendition may be presented via display  40  to indicate successful decoding. 
         [0038]    Reader  15  may send the de-coded results and metrics to the host system. The reader  15  may also send an image  48  of the verified code  28 , as shown in  FIG. 4E . However, the image  48  is limited to the code  28  and a narrow quiet zone  50  therearound only. Additional data captured in the initial image is cropped out by the processor  23  before sending the image  48  to the host system  38 . The image  48  of the code  28  may momentarily be shown on the display  40 , replacing either the background screen  42  or just the graphical representation  46  of the code  28 . 
         [0039]    Upon completion of the decoding process, processor  23  may again present a blank background screen  42  on the display  40  until another item that may correspond to a code  28  is identified. 
         [0040]    In some embodiments, in addition to providing a code representation box or icon  46  on a blank background as in  FIG. 4B , a center of field of view box or icon may also be presented to indicate an ideal or at least suitable location for the code representation  46  that can be used by a reader user to facilitate alignment. To this end see  FIG. 4A  that shows an exemplary center FOV box/shape  44  on otherwise blank screen  42 . Referring also to  FIG. 4B , when an item that may correspond to a code is identified in the camera&#39;s FOV, box  46  is provided at a location corresponding to the location of the item in the field of view. In  FIG. 4B , it should be appreciated that box  46  is misaligned with the center FOV box  44  and therefore the reader  15  or item  22  must be reoriented. Referring to  FIG. 4C , as the reader is reoriented, box  46  moves about on display  40  accordingly until, as in  FIG. 4D , box  46  is aligned with center FOV box  44  and the reader obtains an image and attempts to decode. 
         [0041]    Referring now to  FIG. 5 , a subprocess that may be included in the process of  FIG. 2  for presenting and using a center FOV box  44  is illustrated. Referring also to  FIGS. 1 and 2 , after block  68 , control passes to block  74  where the center FOV box  44  is presented via display  40 . At block  76 , processor  23  monitors to identify when the code representation box  46  is becoming relatively more aligned with box  44 . At block  77  processor  23  provides positive visual or audio feedback as the reader  15  becomes relatively more aligned with the code. Positive visual feedback may include changing the color or box  46  from red to yellow with suitable final alignment being indicated via a green box  46 . 
         [0042]    Referring to  FIG. 6 , a second hand held system  100  that is consistent with at least some inventive embodiments is illustrated. The primary difference between system  100  and reader  15  described above is that the reader  102  in system  100  does not include a display and instead information from reader  102  is transmitted e.g., wirelessly or through a cable (not illustrated) to a computer  104  including a display  106 . Images generated on the hand held display  40  above are generated via display  106  in system  100 . Although the embodiments described above are in the context of a hand held reader, other embodiments are contemplated where a reader is mounted to a stationery structure and items are moved along a transfer line or the line adjacent thereto. In this case the inventive system may be useable during a commissioning process to align a camera FOV with a repeatable location and orientation of codes/marks to be read. Here again, no images other than sub-images of codes would be stored or presented via a display. Moreover, although not illustrated, the inventive code representation system could be used in a mark verification application. 
         [0043]    One or more specific embodiments of the present invention have been described above. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure. For example, in some cases where a reader is to be used with a specific code type, processor  23  may be programmed with a synthetic rendition of a generic instance of the specific code type and that image or a permutation thereof (e.g., squished or skewed depending upon reader orientation with respect to the mark being imaged) may be presented instead of the representation box  46 . Here, the generic instance would, for practical purposes, have the appearance of the mark actually being imaged and decoded. 
         [0044]    Thus, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims. For example: