Abstract:
A method and imaging assembly ( 10 ) are disclosed adapted for reading a target object comprising a scan engine ( 48 ) having a sensor ( 46 ), focusing optics ( 44 ), and an imager ( 48 ). The scan engine includes a field-of-view defining an area to be imaged by the imaging assembly ( 10 ). A housing ( 80 ) internally lodges the scan engine ( 48 ) and an illumination source ( 36 ). The illumination source ( 36 ) is adapted to project illumination from the housing ( 80 ). A boot ( 30 ) extends from the housing ( 80 ) for shaping the illumination as it passes through the boot to form an illumination pattern from the illumination. The illumination pattern substantially conforms to a geometrical shape of the boot ( 30 ) and is adapted to envelope the scan engine field-of-view.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an illumination system for an imaging reader and, more particularly, to an illumination system for an imaging reader including smart illumination that provides a visually defined and prescribed field-of-view in a direction toward a target object for imaging. 
       BACKGROUND 
       [0002]    Various electro-optical systems have been developed for reading optical indicia, such as bar codes. A bar code is a coded pattern of graphical indicia comprised of a series of bars and spaces of varying widths, the bars and spaces having differing light reflecting characteristics. Some of the more popular bar code symbologies include: Uniform Product Code (UPC), typically used in retail stores sales; Code 39, primarily used in inventory tracking; and Postnet, which is used for encoding zip codes for U.S. mail. Systems that read and decode bar codes employing charged coupled device (CCD) or complementary metal oxide semiconductor (CMOS) based imaging systems are typically referred to hereinafter as imaging systems, imaging-based bar code readers, imaging readers, or bar code scanners. 
         [0003]    Imaging systems electro-optically transform the graphic indicia into electrical signals, which are decoded into alphanumerical characters that are intended to be descriptive of the article or some characteristic thereof. The characters are then typically represented in digital form and utilized as an input to a data processing system for various end-user applications such as point-of-sale processing, inventory control, and the like. 
         [0004]    Imaging-based bar code reader systems that include CCD, CMOS, or other imaging configurations comprise a plurality of photosensitive elements (photosensors) or pixels typically aligned in an array pattern that could include a number of arrays. The imaging-based bar code reader systems employ light emitting diodes (LEDs) or other light sources for illuminating a target object, e.g., a target bar code. Light reflected from the target bar code is focused through a lens of the imaging system onto the pixel array. As a result, the focusing lens generates an image from its field-of-view (FOV) that is projected onto the pixel array. Periodically, the pixels of the array are sequentially read out, creating an analog signal representative of a captured image frame. The analog signal is amplified by a gain factor, by for example an operational amplifier or microprocessor. The amplified analog signal is digitized by an analog-to-digital converter. Decoding circuitry of the imaging system processes the digitized signals representative of the captured image frame and attempts to decode the imaged bar code. 
       SUMMARY 
       [0005]    One example embodiment of the present disclosure includes an imaging assembly capable of reading a target object comprising a scan engine having a sensor, focusing optics, and an imager. The scan engine includes a field-of-view that defines an area to be imaged by the imaging assembly. A housing internally lodges the scan engine and an illumination source. The illumination source is adapted to project illumination from the housing. A boot extends from the housing for shaping the illumination as it passes through the boot to form an illumination pattern from the illumination. The illumination pattern substantially conforms to a geometrical shape of the boot and is adapted to envelope the scan engine field-of-view. 
         [0006]    Another example embodiment of the present disclosure includes a method of imaging a target object comprising projecting a field-of-view from a scan engine located in a housing of an imaging assembly and projecting illumination from an illumination source located within the housing to a location outside of the housing by passing the illumination through a boot extending from the housing. The method further comprises shaping the illumination from the illumination source to form an illumination pattern as it passes through the boot. The illumination pattern has a substantially similar shape as the boot. The illumination pattern further envelops the field-of-view such that the illumination pattern is at a fixed offset location relative to the field-of-view. 
         [0007]    A further example embodiment of the present disclosure includes a method of imaging a target object comprising projecting an imaging field-of-view from a scan engine located in a housing of an imaging assembly and projecting illumination from an illumination means located within the housing to a location outside of the housing by passing the illumination through a baffling means extending from the housing. The method further comprises shaping the illumination from the illumination means by redirecting and diffusing at least a portion of the light projected from the illumination means to form an illumination pattern as it passes through the baffling means. The illumination pattern has a substantially similar shape as the baffling means. The illumination pattern further envelops the field-of-view such that the illumination pattern is at a fixed offset location relative to the field-of-view. 
         [0008]    Yet a further example embodiment of the present disclosure includes a hand-held image scanner used for reading target objects comprising a scan engine having a sensor and imager. The scan engine has a field-of-view defining an area to be imaged by the image scanner. The hand-held image scanner further comprises a housing internally lodging the scan engine and an illumination source. The illumination source is adapted to project illumination from the housing. A boot extends from the housing for shaping an illumination pattern from the illumination as it passes through the boot. The illumination pattern forms a fixed envelop distance about at least a portion of the perimeter of the scan engine field-of-view. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The foregoing and other features and advantages of the present invention will become apparent to one skilled in the art to which the present invention relates upon consideration of the following description of the invention with reference to the accompanying drawings, in which: 
           [0010]      FIG. 1  is a perspective view of an imaging reader constructed in accordance with one embodiment of the disclosure; 
           [0011]      FIG. 2  is a top view of the imaging reader of  FIG. 1 ; 
           [0012]      FIG. 3  is a side view of the imaging reader of  FIG. 1 ; 
           [0013]      FIG. 4  is an elevated front view of the imaging reader of  FIG. 1 ; 
           [0014]      FIG. 5A  is a side view of the imaging reader of  FIG. 1  reading a target object located on a package; 
           [0015]      FIG. 5B  is a partial-sectional view of an imaging reader and boot, illustrating an imaging field-of-view and smart illumination projected on a target object; 
           [0016]      FIG. 6  is an image of a smart illumination pattern projected by the imaging reader in  FIG. 5A ; 
           [0017]      FIG. 7  is a perspective view of an imaging reader constructed in accordance with one embodiment of the disclosure; 
           [0018]      FIG. 8  is a perspective view of an object being scanned by the imaging reader of  FIG. 7 ; 
           [0019]      FIG. 9  is a perspective view of an imaging reader constructed in accordance with one embodiment of the disclosure; 
           [0020]      FIG. 10  is an image of a smart illumination pattern projected by the imaging reader in  FIG. 9 ; 
           [0021]      FIG. 11  is a perspective view of an imaging reader constructed in accordance with one embodiment of the disclosure; 
           [0022]      FIG. 12  is an image of a smart illumination pattern projected by the imaging reader in  FIG. 11 ; 
           [0023]      FIG. 13  is a perspective view of an imaging reader constructed in accordance with one embodiment of the disclosure; 
           [0024]      FIG. 14  is an image of a smart illumination pattern projected by the imaging reader in  FIG. 13 ; 
           [0025]      FIG. 15  is a perspective view of one example embodiment of a boot attached to an imaging reader; 
           [0026]      FIG. 16  is a perspective view of one example embodiment of a boot attached to an imaging reader; 
           [0027]      FIG. 17  is a perspective view of one example embodiment of a boot attached to an imaging reader; 
           [0028]      FIG. 18  is a sectional view of the imaging reader of  FIG. 3  along section lines  18 - 18 ; 
           [0029]      FIG. 19  is a sectional view of the imaging reader of  FIG. 2  along section lines  19 - 19 ; and 
           [0030]      FIG. 20  is block diagram illustrating an imaging process using smart illumination in an imaging reader. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    An elevated perspective view of an imaging reader  10  is depicted in  FIG. 1 . The imaging reader  10  is a portable scanner in the illustrated embodiment of  FIG. 1 , employing an internal power source such as a battery, but could just as easily be a reader having a wire connection from which power is supplied, or remotely powered through an induction system without departing from the spirit and scope of the claimed invention. In addition to imaging and decoding 1D and 2D bar codes, including for example postal codes, and Code 39 bar codes, the reader  10  is also capable of capturing images and signatures. In one example embodiment, the imaging reader  10  is a hand held portable scanner that can be carried and used by a user walking or riding through a store, warehouse, or plant, while reading various symbology codes for stocking and inventory control purposes. However, it should be recognized that the imaging reader  10  of the present invention, to be explained below, may be advantageously used in connection with any type of imaging-based automatic identification system including, but not limited to, bar code scanners, signature imaging acquisition and identification systems, optical character recognition systems, fingerprint identification systems, and the like. It is the intent of the present invention to encompass all such imaging-based automatic identification systems. 
         [0032]    Referring now to  FIGS. 1-4 , the imaging reader  10  includes a handle  12 , which is located between an upper end  14  and lower end  16  of the reader  10 . The reader  10  further includes a head  18  situated between first and second ends  20  and  22 , respectively. Extending from and connected to the reader head  18  is a boot  30 . The boot  30 , as discussed further in detail below, provides visually defined fixed and prescribed illumination pattern in a direction toward a target object  32 , such as a bar code for imaging, as illustrated in  FIG. 5A . The target object  32  in  FIG. 5A  is located on a package  34  and in addition to being any indicia form of symbology, the target object could also be located on any type of product or packaging. 
         [0033]    An imager field-of-view FOV is projected from the imaging reader  10  as best seen in  FIG. 5A  and in the partial sectional view of the imaging reader in  FIG. 5B . The imager FOV is the extent of the area imaged by the reader  10  and identified as area A in  FIGS. 5A and 5B . In the illustrated embodiment of  FIGS. 5A and 5B , the imager FOV extends beyond the outer limits Z 1  and Z 2  of the target object  32 , however it could also reside within the outer limits Z 1  and Z 2  for certain symbology types and still successfully image the target object  32 . 
         [0034]    An illumination source  36  is located in the imaging reader  10  and in combination with the boot  30 , projects smart illumination illustrated as an illumination pattern  38  identified by the area B in  FIGS. 5A and 5B . In the illustrated embodiment, the imaging process is manually initiated by a trigger  40  located on the handle  12  of the imaging reader  10 . When the trigger  40  is engaged, it enables the illumination from the illumination source  36  that is shaped by the boot  30  to form the illumination pattern  38 . An operator when using the imaging reader  10 , projects the illumination pattern  38  upon the target object  32 . Automated image reader systems can also be used without departing from the spirit and scope of the claimed invention, which are initiated by an instruction internal to the reading system&#39;s software or circuitry. Alternatively, the initiation of the automatic reading system may be continuous once power is supplied to the reader. For either the manual or automatic reading systems, the illumination source  36  is energized, projecting the illumination through the boot  30  that shapes the illumination pattern  38  projected from the imaging reader  10 . 
         [0035]    The illumination pattern  38  is a prescribed pattern defined by the geometry of the boot  30 . The illumination pattern  38  comprises an envelop distance           located just beyond the imager FOV. In the illustrated example of  FIG. 5B , the imager FOV is at an angle θ A  about an optical axis OA of the imaging reader  10 . The illumination pattern  38  defined by the boot  30  provides a fixed angle θ B  about the optical axis OA. The boot  30  truncates light that would normally pass from the reader absent the boot and reallocates light into the illumination pattern  38  such that 
         [0000]                =θ B −θ A    
         [0000]    for all illumination patterns  38  relative to the imager FOV about the optical axis OA. 
         [0036]    The illumination source  36  can be a single light emitting diode (LED), bank of LEDs, LEDs projecting light through a lens, a cold cathode lamp (CFL), or an LED projecting light through one or more light pipes  42  as illustrated in  FIGS. 18 and 19 .  FIGS. 18 and 19  are sectional views of the imaging reader  10  for  FIGS. 3 and 2 , respectively. 
         [0037]    Once the illumination pattern  38  is defined by the boot  30  and projected from the imaging reader  10 , an image from the target object  32  is reflected back toward the imager into focusing optics  44  that includes a single or plurality of lenses. The focusing optics  44  then focuses the reflected image onto an imaging sensor  46 , such as a multi-dimensional pixel array, filling the pixel array with data. The imaging sensor  46  is coupled to an imager positioned on a printed circuit board  48  (PCB). The imaging sensor produces a data grid corresponding to the reflected image from the target object  32 . It should be appreciated by those skilled in the art that the imaging sensor  46  such as a pixel array and imager could be either a charged coupled device (CCD) or complementary metal oxide semiconductor (CMOS) based imaging type array, both having multi-dimensional array of sensors that sense the reflected image and form pixel data corresponding to the image of the target object  32 . 
         [0038]    An analog to digital (“A/D”) converter is located on the PCB  48  receives the stored analog image from the imager. The A/D converter then sends a digital signal to a decoder located either on the PCB  48  or remotely from the imaging reader  10 . The signal is then synthesized by the decoder&#39;s internal circuitry. The PCB  48  may further include a microprocessor that assists in processing and decoding the image into a data stream through software or firmware. The firmware and/or software includes computer readable media embedded within the microprocessor onto for example, flash Read Only Memory (ROMs) or as a binary image file that can be programmed by a user. Alternatively, the PCB could include an application specific integrated circuit (ASIC). 
         [0039]    If the decode process executed within the decoder is successful, the decode session may be terminated with the decoded information being transmitted to an output of the PCB  48 , which could be tied to a number of reader peripherals. The periperherals include for example, visual display devices such as a monitor or LED, a speaker, or the like. The imaging reader  10  could further include a laser diode  50  that assists by projecting an aiming pattern onto the target object  32 . Further, a bezel diffuser  52  is illustrated in  FIGS. 18 and 19  that assists in scattering the light from the illumination source  36 . 
         [0040]    The sectional views of  FIGS. 18 and 19  further illustrate the truncating and reallocating of the illumination in the illumination pattern  38  shaped by the boot  30 . In particular, it can be seen that the boot  30  clips or truncates the light beams  60  emitted from the light pipes  42  and instead, redirects the beams to be concentrated within the illumination pattern  38 . For example, redirected light beams  62  are diffused within the boot  30  and projected upon the target object  32  within the illumination pattern  38 . Accordingly, the illumination pattern  38  can assist the user in directing the gun toward the target object  32 . 
         [0041]    The boot  30  is made from any type of reflective or diffuse material. In the illustrated embodiments, the boot  30  is made from diffuse white plastic, such as thermoplastic TEXAN® 950 manufactured by Bayer MaterialScience LLC, of Pittsburg, Pa. The geometry of the boot  30  is reflected in the shape of the illumination pattern  38 , producing a sharp light intensity boundary in which illumination is significantly reduced outside the boundary of the illumination pattern. Stated another way, the illumination pattern  38  can be shaped to reflect a desired geometry based on the configuration of the boot  30 . For example, the oval-shaped boot  30  in  FIG. 5A  provides an oval-shaped illumination pattern  38  illustrated in  FIG. 6 , the round-shaped boot  30  in  FIG. 9  provides round-shaped illumination pattern  38  illustrated in  FIG. 10 , the rectangular-shaped boot  30  in  FIG. 11  provides a rectangular-shaped illumination pattern  38  illustrated in  FIG. 12 , and the boot  30  in  FIG. 13  comprising left and right sides projects a sharp left and right contrast in the illumination pattern  38  of  FIG. 14 . 
         [0042]    In addition to shaping the illumination pattern  38 , the boot  30  can be used to position a package or object during imaging, as illustrated in  FIGS. 7 and 8 . The boot  30  in the illustrated embodiment of  FIGS. 7 and 8  includes a plurality of slots  70  for guiding and supporting an object  72  during imaging, such as a tube. Further, the boot  30  could include an upper recess  74  illustrated in  FIGS. 1-4  to allow the user of a handheld image reader  10  in close proximity scans to see over the reader and view the target object  32  and/or illumination pattern  38 . A corresponding lower recess  74 ′ is provided symmetrically about the OA so that the illumination pattern  38  is uniform along its upper and lower profiles. The illustrated embodiment of  FIG. 13  provides additional viewing clearance for the user by constructing the boot  30  to have only left and right sides. 
         [0043]    Referring again to  FIGS. 18 and 19 , the imaging reader  10  includes a housing  80  surrounded by overmolded rubber  82 . The boot  30  can be integrally connected to the housing  80 , or be detachably connected so that different sizes can be used to accommodate different imager FOVs and imaging applications. For example,  FIGS. 15-17  illustrate three different example embodiments of a detachable boot  30 . In  FIG. 15 , the boot  30  comprises a plurality of slots  84  about its perimeters that engage a corresponding boss (not shown) located in the housing  80  of the imaging reader  10 . The slots allow for the amount of extension of the boot  30  beyond the head  18 . 
         [0044]    In an alternative example embodiment illustrated in  FIG. 16 , the boot  30  includes a plurality of apertures  86  that can be selected for adjusting the depth by engaging at least one aperture with a corresponding boss (not shown) located within the housing  80  of the imaging reader  10 . Further, the multiple apertures  86  can be used to engage more than one corresponding boss to facilitate additional support and an anti-rotation connection. In yet another alternative example embodiment illustrated in  FIG. 17 , the boot  30  includes a number of bosses  88  where at least one is selectively received by a corresponding recess (not shown) in the housing  80 , allowing adjustment to the amount of extension of the boot beyond the head  18 . 
         [0045]      FIG. 20  illustrates a process  100  for using and adjusting an imaging reader  10  having a boot  30  for projecting an illumination pattern  38 . The amount of adjustment of the boot is along the distance X illustrated in  FIG. 5B . At  102 , the imager FOV is determined. At  104 , the imaging reader is enabled. At  106 , a determination is made on whether the illumination pattern enveloped the imager FOV. If the determination at  106  is an affirmative, the process ends at  108 . If the determination at  106  is negative, a determination is made at  110 . The determination at  110  is whether the illumination pattern extends outside the imager FOV. If the determination at  110  is an affirmative, a determination is made at  112 . The determination at  112  is whether the illumination pattern extends too far outside the imager FOV. If the determination at  112  is an affirmative, the length of the boot should be increased at  114  and the process is repeated at step  106 . If the determination at  112  is negative, the process is repeated as at step  106 . If the determination at  110  is negative, the length of the boot should be decreased at  116  and the process is repeated at step  106 . 
         [0046]    What have been described above are examples of the present invention. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the present invention, but one of ordinary skill in the art will recognize that many further combinations and permutations of the present invention are possible. Accordingly, the present invention is intended to embrace all such alterations, modifications, and variations that fall within the spirit and scope of the appended claims.