Single arch portal scanner and method of scanning

A scanning system for data reading, and related methods of use, the scanning system including a portal scanner and a conveyor for transporting items. The scanner includes a generally U-shaped scanner housing and a plurality of data readers arranged within the scanner housing for reading data on various surfaces of an item being transported through the portal scanner. The scanning system may also include a bottom scanner positioned beneath the conveyor, the bottom scanner having a view volume directed through a gap in the conveyor for reading a bottom surface of the item through the gap as the item passes over the gap. In some embodiments, the scanning system may further include one or more light curtains configured for determining a height dimension of the item and/or a position of the item.

BACKGROUND

The field of this disclosure relates generally to data reading systems, and more particularly to automated data reading systems where items are transported through a read region of one or more data readers at which the items are identified by reading optical codes, RFID (radio frequency identification) tags, other identifiers carried on the items, or by capturing and processing images of the items.

Data reading systems are used to read optical codes, acquire data, and/or capture images to identify an item. Data reading devices are well known for reading UPC and other types of optical codes on packages, particularly in retail stores. One common data reader in such systems is an imaging reader that employs an imaging device or sensor array, such as a CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor) device. Imaging readers can be configured to read both 1-D and 2-D optical codes, as well as other types of optical codes or symbols and capture images of other items. When an imaging reader is used to read an optical code, an image of the optical code or portion thereof is focused onto a detector array. Though some imaging readers are capable of using ambient light illumination, an imaging reader typically utilizes a light source to illuminate the item being read to provide the required signal response in the imaging device.

An imager-based reader utilizes a camera or imager to generate electronic image data, typically in digital form, of an optical code. The image data is then processed to find and decode the optical code. For example, virtual scan line techniques are known techniques for digitally processing an image containing an optical code by looking across an image along a plurality of lines, typically spaced apart and at various angles, somewhat similar to the scan pattern of a laser beam in a laser-based scanner. It should be noted that a camera is typically a combination of a lens and an imaging device/sensor array, but the terms imager and camera may be used interchangeably herein.

Imager-based readers often can only form images from one perspective—usually that of a normal vector out of the face of the imager. Such imager-based readers therefore provide only a single point of view, which may limit the ability of the reader to recognize an optical code in certain circumstances. For instance, because the scan or view volume of an imager in an imager-based reader is typically conical in shape, attempting to read a barcode or other image in close proximity to the scanning window (reading “on the window”) may be less effective than with a basket-type laser scanner. Also, when labels are oriented such that the illumination source is reflected directly into the imager, the imager may fail to read properly due to uniform reflection washing out the desired image entirely, or the imager may fail to read properly due to reflection from a textured specular surface washing out one or more elements of the barcode. This effect may cause reading of shiny labels to be problematic at particular reflective angles. In addition, labels oriented at extreme acute angles relative to the imager may not be readable. Lastly, the label may be oriented on the opposite side of the package with respect to the camera view, causing the package to obstruct the camera from viewing the barcode.

Thus, better performance could result from taking images from multiple perspectives. Imager-based readers that generate multiple perspectives are known. For example, one such reader is disclosed in U.S. Pat. No. 7,398,927 which describes an embodiment having two cameras to collect two images from two different perspectives for the purpose of mitigating specular reflection. In addition, U.S. Pat. No. 6,899,272 discloses a data reader that utilizes two independent sensor arrays pointed in different orthogonal directions to collect image data from different sides of a package.

However, in some multiple-camera imager-based readers that employ spatially separated cameras, the system may require multiple circuit boards and/or mounting hardware and space for associated optical components. Such features and components may increase the expense of the data reading system, complicate the physical design, and increase the size and bulk of the data reading system. The present inventors have, therefore, determined that it would be desirable to provide a data reading system with improved performance features, while maintaining a lean profile to minimize cost and size (e.g., bulk) of the data reading system.

Additional aspects and advantages will be apparent from the following detailed description of preferred embodiments, which proceeds with reference to the accompanying drawings. Understanding that the drawings depict only certain embodiments and are not, therefore, to be considered limiting in nature, these embodiments will be described and explained with additional specificity and detail with reference to the drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to the drawings, this section describes particular embodiments and their detailed construction and operation. The embodiments described herein are set forth by way of illustration only and not limitation. The described features, structures, characteristics, and methods of operation may be combined in any suitable manner in one or more embodiments. In view of the disclosure herein, those skilled in the art will recognize that the various embodiments can be practiced without one or more of the specific details or with other methods, components, materials, or the like. In other instances, well-known structures, materials, or methods of operation are not shown or not described in detail to avoid obscuring more pertinent aspects of the embodiments.

In the following description of the figures and any example embodiments, it should be understood that an automated checkout system in a retail establishment is merely one use for such a system and should not be considered as limiting. An automated checkout system with the characteristics and features described herein can alternatively be used, for example, in an industrial location such as a parcel distribution center (e.g., postal), warehouse, or luggage distribution center. In addition, though the portal scanner100and the bottom scanner50may be described in greater detail as an optical code reader or data reader, the portal scanner100and/or bottom scanner50may alternately comprise an RFID reader, an image or object recognition reader, an optical code reader, or combinations thereof.

In addition, it should be understood that reference to a “data reader” in the specification is used in an expansive sense to describe a data reader that may include a camera or other imaging system, a microprocessor, a decoding unit, and a controller for communicating data to other data readers or external systems. However, the term “data reader” is not intended to be limited to require each of these components. In some embodiments, a data reader may include a camera or other imaging system, and may not include a processor, decoding unit, and the controller. These components may be entirely external to the data reader itself, such as being a part an external system with which the data reader communicates. For example, the data reader may be a camera that obtains images of the item and communicates or transmits those images to an external database for decoding and processing. While it is generally understood that a camera is typically a combination of a lens and an imaging device or sensor array, the terms imager (or imaging system) and camera may be used interchangeably herein.

FIGS. 1-2illustrate an automated checkout system10that may be used to read and process an optical code (e.g., a barcode label) or capture other target data (RFID tags, images, etc.) from various surfaces of an item20during a checkout process, such as in a retail establishment or supermarket. The automated checkout system10includes a portal scanner100attached to a chassis132. The chassis132is installed at a checkstand5that may be used at a high-volume retail establishment, such as a grocery store or big-box store. The automated checkout system10also includes a conveyor system14having a front conveyor section (or leading/input conveyor)15and a rear conveyor section (or trailing/exit conveyor)16for transporting items20through a read region of the portal scanner100. The checkstand5includes a base or stand7having a front end section11for supporting the input conveyor15and a rear end section12for supporting the exit conveyor16. The front end section11has a feed-in shelf13on which items20may be laid prior to and in preparation for placing on the input conveyor15. The lower section of the stand7is shown with a bottom of basket/cart detector9that detects and possibly identifies items20on the bottom shelf of a grocery basket or cart. Such detection may be used to alert the customer and/or store personnel that potentially forgotten items20remain in the basket, or to otherwise process items20that are either large or bulky and left on the bottom shelf of the grocery basket/cart.

In some embodiments, the input conveyor15and the exit conveyor16are spaced apart by a gap18. In such embodiments, the automated checkout stand10further includes a bottom scanner50attached to or otherwise supported by the chassis132, and positioned to read a bottom side28of the item20through the gap18(seeFIG. 3). In some embodiments, the input conveyor15may be slightly raised in relation to the exit conveyor16(i.e., the input conveyor terminates at a slightly raised elevation proximate and relative to the exit conveyor) such that when the item20transitions from the input conveyor15to the exit conveyor16, the item20crosses the gap18and tilts or drops slightly onto the exit conveyor16. In other embodiments, the bottom scanner50and the gap18may be omitted, and a single, continuous conveyor14(instead of separated conveyor sections15,16) may be employed.

It should be understood that although the transport systems are generally described with respect to belt-type conveyors, other conveyor/transport systems may be employed such as: inclined slides, vibratory conveyors, roller conveyors, turntables, blower systems (the items driven along a surface via a blower), combinations thereof, or other suitable transport systems.

In an example operation, a checkout clerk38or customer40(sometimes, separately or collectively referred to as a “user”) places the item20onto the input conveyor15, which transports the item20in a substantially linear direction of motion22toward the portal scanner100. The item20moves through a read volume or read region150(seeFIG. 3) of the portal scanner100. With reference toFIG. 3, the read volume or region150may be defined by the collective views of the data readers140,145of the portal scanner100and the bottom scanner50. As the item20moves across the gap18and through the read region150of the portal scanner100, the data readers140,145(seeFIG. 13) of the portal scanner100and the bottom scanner50capture an image of the item20. The image is then processed to decode the barcode label (or other data) captured in the image. After passing through the portal scanner100, the item20is transported on the exit conveyor16to a bagging area17where the user or other person can bag or box the item20for removal by the customer40. Other embodiments and additional details of an example portal scanner, including a bottom scanner, are disclosed in U.S. App. Pub. No. 2013/0020392, filed Jan. 24, 2011, hereby incorporated by reference.

For general purposes of discussion, the item20is represented as a six-sided, box-shaped package. In some instances, the item20may be described with respect to its direction of motion22on the conveyors15,16. In addition, any description regarding the position of a checkout clerk38and a customer40is meant to facilitate description and establish a frame of reference related to a typical position of the checkout clerk38and the customer40, as illustrated inFIG. 1, and is not intended to be limiting. For instance, the item20may be described as having a top side26, a bottom side28, and four lateral sides30,32,34, and36. The lateral sides may be referred to as the leading (or front lateral) side30(the side leading the object as it is passed through the read region), the trailing (or rear lateral) side32(the trailing side of the object as it is passed through the read region), the checker (or left lateral) side34(due to its proximity to a checkout clerk38), and the customer (or right lateral) side36(due to its proximity to a customer40).

It should be understood that the automated checkout stand10may be used without a checkout clerk38, and/or the customer40(or clerk38) may be positioned at any side of the automated checkout stand10. In addition, the item20is described as a box-shaped package for convenience, but it should be understood that the item20may encompass other shapes, including, for example, round fruits or vegetables, cylindrical cans, irregularly shaped packages, such as a bag of potatoes, potato chips, or the like.

With reference toFIG. 2, the portal scanner100includes a generally inverted U-shaped arch having a top section110connected to left and right lateral leg sections120,130, respectively. The top section110, and leg sections120,130house a plurality of data readers140,145each of which includes one or more cameras/imagers or other imaging systems and corresponding optics and other components (seeFIG. 6for example). As is discussed in further detail below, the data readers140,145collectively form a read region150generally defined to include the inner space or enclosed area within the boundaries of the portal scanner100(seeFIG. 3). In some embodiments, the read region150may extend outside (e.g., in front of and/or behind) the footprint of the portal scanner100depending on the angular orientation of the view volumes of the data readers140,145. Preferably, the left and right leg sections120,130have identical configurations and are interchangeable to simplify manufacturing and assembly. Identical configurations also allow for the scanner sections110,120,130to be disassembled and stacked in a more compact package thus saving on shipping, staging, and storage costs.

As mentioned previously, when assembled, the left and right leg sections120,130extend generally downwardly (or in some embodiments, orthogonally) from opposite ends of the top section110to create an inverted U-shaped arch. With reference toFIG. 1, the portal scanner100is preferably attached to a chassis or structure132which is mounted on the checkstand5between the front end section11and the rear end section12. In such embodiments, the top section110extends across a width of the conveyors15,16and the leg sections120,130are mounted to the chassis132with a small clearance to avoid interfering with the conveyors15,16. Preferably, the portal scanner100is mounted on the chassis132such that the top section110is aligned with and overlaps the gap18. In some embodiments, the top section110is centered over the gap18when the portal scanner100is installed on the checkstand5.

As shown inFIGS. 1-2, the portal scanner100embodies a streamlined design with an open and airy architecture that is less bulky than a large enclosed tunnel structure. The minimal structure or configuration also provides sight lines for the customer40to see the items20passing through the read region150. However, the portal scanner100nonetheless maintains sufficient structure to limit access to items20passing through the read region150(e.g., by the lateral leg sections120,130) to help avoid inaccurate readings and/or to enhance security of items20being processed.

In some embodiments, to further enhance security, a security camera160may be positioned within the top section110and/or within each of the leg sections120,130. For instance, in one embodiment (seeFIG. 6), the security camera160may be positioned near the scan window254and the illumination modules256to avoid interfering with the view volume225of the data readers140(or data reader145) of the top section110. The security camera160preferably has a wide field of view to capture both the entry point of the item20(e.g. as the item20is transported on the entry conveyor15toward the portal scanner100) and the exit point of the item20(e.g., as the item20is transported on the exit conveyor16toward the bagging area17). In other embodiments, such as illustrated inFIG. 3, two individual security cameras165(rear camera not shown) may be used and positioned on an exterior surface of the top section110, with one camera165facing the entry side (e.g., toward the input conveyor15) and the other camera (not shown) facing the exit side (e.g., toward the exit conveyor16). The security cameras may also be used to track and identify items20that pass through the portal scanner100without having their respective identifying information (e.g., barcode labels) read by the portal scanner100or bottom scanner50. These items20may be referred to as exception items, which are items that need to be reprocessed through the portal scanner100to obtain the barcode labels or other information.

Internal read optics will now be described in more detail. As previously mentioned, internal read optics are disposed within (1) the leg sections120,130of the portal scanner100; (2) the top section110of the portal scanner100; and (3) the bottom data reader60(seeFIG. 13). Though the detailed example configuration of the portal scanner will be described as comprising of twelve cameras or imagers with each having multiple views, other reading system combinations may be employed including other imaging configurations with more or fewer cameras, laser reading systems, combinations thereof, or even including RFID readers.

FIG. 3illustrates a simplified perspective view of the automated checkout system10illustrating view volumes of a plurality of data readers140,145,60(seeFIG. 13). As further described in detail below, the data readers140,145are housed within the leg sections120,130and the top section110, respectively, of the portal scanner100(seeFIG. 13). The automated checkout system10also includes a bottom scanner50separate from the portal scanner100that may be housed within the chassis132, the bottom scanner50housing a plurality of data readers60therein (seeFIG. 13). The data readers140,145,60each include one or more cameras or imaging system, each camera directing an individual view volume generally within the outer confines or footprint of the portal scanner100. Collectively, the view volumes overlap or cross one another and define a read region150of the automated checkout system10. When the item20travels through the read region150, one or more of the data readers140,145,60capture the optical code label (or other target data) from the item20for processing.

For purposes of description, the read region150and the view volumes (e.g.,225,230described below) illustrated in dashed lines in the figures are a 3D volume of space in which there is a high probability of a successful read of an optical code placed within that volume of space. It should be noted that the read region150and the view volumes shown in the figures are not an exact representation but merely an illustration of the volumetric region in which the portal scanner100may be capable of reading optical codes placed therein. Other factors may affect the volumetric region for a successful read, such as the depth of field of the readers.

In some embodiments, the read region150may be substantially confined within the enclosed area of the portal scanner100. In other embodiments, the read region150may extend outside or beyond the footprint of the portal scanner100. For example, the data readers145in the top arch section110may have view volumes that partially extend beyond the portal scanner100to obtain an image of the item20prior to it entering the physical boundary of the portal scanner100, or after it leaves the portal scanner100on the exit conveyor16. Further details relating to the view volumes of the data readers140,145,60are described below.

The reading function from the leg sections120,130will be described first with respect toFIGS. 4-6. In the following description, the reading function will be described with respect to leg section130for convenience with the understanding that leg section120may include identical or substantially similar components arranged in an identical or substantially similar configuration. Preferably, the leg sections120,130have identical camera and optics configurations for each of the data readers, but it should be understood that adjustments may be made to one or both leg sections120,130to alter the reading functions as desired.

In the following description, the specific details of the data readers140,145,60, including optics arrangements and image views generated therefrom, are described for the leg sections120,130, the top section110, and the bottom data reader60. Although the optics and image views are described for a single data reader positioned in each of these sections, it should be understood that each of the leg sections,120,130, the top section110, and the bottom scanner50may include multiple data readers that collectively generate a number of individual views as further discussed with respect toFIG. 14.

FIGS. 4-5illustrates view volumes225,230of the data readers140housed in the leg section130.FIG. 6illustrates further details of the data reader140and an optics set220, including an imager (or camera)232. The optics set220is disposed within the leg section130of the portal scanner100as described previously. With particular reference toFIGS. 4-5, the optics set220produces a pair of view volumes225,230facing sidewardly (e.g., transversely across the conveyors15,16) from the leg section130in a crisscrossing configuration so that the view volumes225,230intersect or cross one another. The point of intersection between the view volumes225,230may depend on various factors, such as the spacing or separation between the respective cameras and the angle of the view volume, for example. The view volumes225,230, together with the view volumes from the opposite leg section120, span across the conveyor sections15,16to collectively capture a view of the checker and customer sides34,36of the item20(and in some cases the leading and trailing views30,32).

In some embodiments, the first view volume225is aimed rearwardly relative to the direction of motion22of the item20(i.e., aimed toward the front end section11of the checkstand5) for obtaining images of the leading side30, and the checker side34(and in some instances the top side26) of the item20as it passes through the portal scanner100traveling in the direction of motion22(seeFIG. 1). The second view volume230is aimed forwardly relative to the direction of motion22(i.e., aimed toward the rear end section12of the checkstand5) for obtaining images of the checker side34, the trailing side32(and in some instance the top side26). As briefly mentioned above, the other leg section120includes a similar arrangement of data readers with view volumes to capture the customer side36, the leading side30, and the trailing side32(and in some instances, the top side26).

With particular reference toFIG. 6, details of the optic set220and view volumes225,230for the leg section130will now be described.FIG. 6illustrates both the first and second view volumes225,230produced from the optics set220. Optic set220includes the camera along with the mirror sets. The camera comprises an imager232mounted on an image board (PCB)234and the focusing lens236for focusing the incoming image from the view volumes225,230onto the imager232. Preferably, the images from each of the view volumes225,230are focused onto a common imager232. For instance, images from the first view volume225are focused on one region of the imager232and images from the second view volume230are focused on a different region of the imager232.

FIG. 6is a diagrammatic top view of the optics set and mirror configuration for reflecting view volumes225,230along respective image paths to the imager232. When an item20travels on the automated checkout system10, an image of the item20is captured as the item20passes through the view volumes225,230. The captured image is propagated by the mirrors252,250,244,242,240and ultimately focused on the imager232as further described in detail below. The view volumes225,230may be illuminated by one or more illumination sources256(e.g., LED arrays) positioned near the scan window254to improve image capture capabilities.

With respect to the first view volume225, the image of the item20is captured in the view volume225and is propagated through a scan window254along a first image path segment225a. First image path segment225ais reflected sidewardly by a first mirror252along a second image path segment225bto a second mirror250, which reflects the image forwardly (i.e., toward the scan window254) along a third image path segment225ctoward a first mirror portion246of a third or split mirror244. The first mirror portion246reflects a fourth image path segment225drearwardly (i.e., toward the imager232) to a fourth mirror242, which reflects a fifth image path segment225eforwardly to a fifth mirror240, which reflects the image along a sixth image path segment225fto the imager232supported on the PCB234. The image may be focused by a suitable focusing lens236positioned in front of the imager232.

Similarly, with respect to the second view volume230, an image of the item20is captured in the view volume230and is propagated through the scan window254along a first image path segment230a. First image path segment230ais reflected sidewardly by the second mirror250along a second image path segment230bto the first mirror252, which reflects the image forwardly along a third image path segment230ctoward a second mirror portion248of the split mirror244. The second mirror portion248reflects a fourth image path segment230drearwardly to the fourth mirror242, which reflects a fifth image path segment230eforwardly to the fifth mirror240, which reflects the image along a sixth image path segment230fto the imager232supported on the PCB234. The image may be focused by a suitable focusing lens236positioned in front of the imager232.

FIG. 7illustrates a view volume of the data readers145housed in the top section110of the portal scanner100. Preferably, the data readers145have an identical or substantially similar optics arrangement as described with respect to the data readers140ofFIGS. 4-6. To avoid repetition, the description regarding the optics set of the data readers145will not be further described in detail. As with the optics set220, the optics set for the data readers145includes an imager and a lens. With particular reference toFIG. 7, the optics set for the data readers145produces a pair of view volumes260,265facing downwardly from the top section110in a similar crisscrossing configuration as the view volumes230,235described inFIG. 6so that the view volumes260,265intersect or cross one another. As described previously with respect toFIG. 4, the point of intersection between the view volumes260,265may depend on various factors, such as the spacing or separation between the respective cameras and the angle of the view volume, for example.

The data reader145in the top section110has a rear view volume260(i.e., facing toward the input conveyor15) and a forward volume265(facing toward the exit conveyor16) directed generally downward from the top section110toward the conveyors15,16. The rear view volume260is aimed downwardly and slanted rearwardly from the top section110and upstream of the gap18(i.e., aimed toward the front end section11of the checkstand5) for obtaining images of the top side26and the leading side30of the item20as it enters and passes through the portal scanner100traveling in the direction of motion22(seeFIG. 1). The forward view volume265is aimed downwardly and slanted forwardly from the top section110and downstream of the gap18(i.e., aimed toward the rear end section12of the checkstand5) for obtaining images of the top side26and the trailing side32of the item20as it passes through and exits the portal scanner100.

Preferably, to avoid any blind spots in the collective read region150of the data readers145,150, the view volumes225,230,260,265are arranged to overlap with each other, thereby collectively capturing a complete view of all sides30,32,34,36and the top26of the item20. In addition, the view volumes225,230,260,265allow the portal scanner100to obtain images or capture other data from the items20when the items20are outside (i.e., either in front or behind) the arch structure of the portal scanner100.

FIG. 8illustrates a read region of the bottom scanner50. In one embodiment, the bottom data readers60housed within the bottom scanner50each has an identical or substantially similar optical arrangement as the data readers145,150on the leg and top sections110,120,130of the portal scanner100. With reference toFIG. 8, the bottom data readers60include an optics set that produces view volumes270,275facing upwardly through the gap18in a similar crisscrossing configuration as the view volumes225,230,260,265previously described for the data readers140,145. The view volumes270,275are directed through the gap18for reading a bottom side28of the item20as the item20transitions between the conveyors15,16.

In some embodiments, the rear view volume270is aimed upwardly and slanted rearwardly from the bottom scanner50and upstream of the gap18(i.e., aimed toward the input conveyor15) for obtaining views of the bottom side28and sometimes the leading side30of the item20as it enters the portal scanner100and crosses the gap18traveling in the direction of motion22(seeFIG. 1). The forward view volume275is aimed upwardly and slanted forwardly from the bottom scanner50and downstream of the gap18(i.e., aimed toward the exit conveyor16) for obtaining images of the bottom side28and the trailing side32of the item20as it crosses the gap18and exits the portal scanner100. Preferably, to avoid any blind spots in the read region150, the view volumes270,275are arranged to overlap with the view volumes225,230,260,265of the data readers140,145so that the data readers140,145,60may collectively capture an image from all sides30,32,34,36, the top side26, and the bottom side28of the item20.

In some embodiments, the bottom data reader60may be a linear imager and the view volumes270,275may be single line/planar views directed up through the gap18. With particular reference toFIG. 9, the bottom data reader60in this arrangement may have a similar optics arrangement as the data reader140. In particular, an optic set300includes the camera along with the mirror sets as illustrated inFIG. 9. The camera comprises an imager302mounted on an image board (PCB)304and a focusing lens306for focusing the incoming image onto the imager302. The view volumes270,275may be illuminated by one or more illumination sources322(e.g., LED arrays) positioned near the scan window320to improve data reading capabilities.

With respect to the first view volume270, the image of the item20is captured in the view volume270and is propagated through a scan window320along a first image path segment270a. First image path segment270ais reflected sidewardly by a first mirror318along a second image path segment270bto a second mirror316, which reflects the image forwardly (i.e., toward the scan window320) along a third image path segment270ctoward a first mirror portion312of a third or split mirror324. The first mirror portion312reflects a fourth image path segment270drearwardly (i.e., toward the imager302) to a fourth mirror310, which reflects a fifth image path segment270eforwardly to a fifth mirror308, which reflects the image along a sixth image path segment270fto the imager302supported on the PCB304. The image may be focused by a suitable focusing lens306positioned in front of the imager302.

Similarly, with respect to the second view volume275, an image of the item20is captured in the view volume275and is propagated through the scan window320along a first image path segment275a. First image path segment275ais reflected by the second mirror316along a second image path segment275bto the first mirror318, which reflects the image forwardly along a third image path segment275ctoward a second mirror portion314of the split mirror324. The second mirror portion314reflects a fourth image path segment275drearwardly to the fourth mirror310, which reflects a fifth image path segment275eforwardly to the fifth mirror308, which reflects the image along a sixth image path segment275fto the imager302supported on the PCB304. The image may be focused by a suitable focusing lens310positioned in front of the imager302.

FIGS. 10-12illustrate another embodiment of an optics arrangement for the data readers350of the portal scanner100, where the data readers350incorporate a dual-camera configuration. One of the cameras has a wide field-of-view (i.e., short focal length) with a pair of crisscrossing, near-field view volumes360,365, while the other of the cameras has a narrow field-of-view (i.e., long focal length) with a pair of crisscrossing far-field view volumes460,465. For instance, in one embodiment, the wide field-of-view camera may use a 25 mm lens and the narrow field-of-view camera may use a 35 mm lens.

The view volumes360,365,460,465, are arranged in a similar configuration as described in previous embodiments to read the sides30,32,34,36and the top26of the item20(e.g., the view volumes are aimed downwardly from the top section110or transversely from the leg sections120,130depending on whether the cameras are on the top section110or leg sections120,130of the portal scanner100). In some embodiments, the bottom scanner50may or may not have a dual-camera configuration.

This dual camera configuration of the data reader350may be used in the top section110and/or the leg sections120,130of the portal scanner100(e.g., in place of the data readers140,145). This configuration provides one camera with a long depth of field to optimize the reading of large, low density optical code (e.g., barcode) labels or labels at longer distances from the camera, and the other camera with a shorter depth of field to optimize the reading of smaller, higher density labels or labels at shorter distances from the camera.

As is further described in detail below, the two cameras may share a common set of mirrors and may have optical paths propagated by the mirrors in a collinear configuration relative to one another (e.g., the optical path of the near-field camera may be slightly offset above or below the optical path of the far-field camera). Accordingly, in the following description, similar components and features are described concurrently to avoid repetition and confusion. When describing identical components between the two cameras, the description uses reference numerals in the 300-series to refer to the components of the near-field camera and uses reference numerals in the 400-series (in parenthesis) to refer to the components of the far-field camera.

The details of the optics set370,470and view volumes360,365,460,465will now be described. In some embodiments, the optics and mirror configurations for the dual-camera configuration may be substantially similar to the optics and mirror configuration described with respect to the previous embodiments. The optics set370(or470) comprises an imager372(or472) mounted on a shared image board (PCB)332and a focusing lens374(or474) for focusing the incoming image onto the imager372(or472). Since the view volumes360,365of the near-field camera and the view volumes460,465of the far-field camera may be collinear and exit the scan window330in the same general region, the view volumes may be illuminated by a common illumination source348(e.g., LED arrays) positioned near the scan window330to improve image capture capabilities.

For ease of illustration, the collective view volumes for the dual-camera configuration were separated into two halves inFIGS. 11 and 12. With particular reference toFIG. 11, an image of the item20captured in the view volume365(or465) is propagated through a scan window330along a first image path segment365a(or465a). First image path segment365a(or465a) is reflected sidewardly by a first mirror344along a second image path segment365b(or465b) to a second mirror346, which reflects the image forwardly (i.e., toward the scan window330) along a third image path segment365c(or465c) toward a first mirror portion342of a third or split mirror338. The first mirror portion342reflects a fourth image path segment365d(or465d) rearwardly (i.e., toward the PCB332) to a fourth mirror336, which reflects a fifth image path segment365e(or465e) forwardly to a fifth mirror334, which reflects the image along a sixth image path segment365f(or465f) to the imager372(or472) supported on the PCB332. The image may be focused by a suitable focusing lens374(or474) positioned in front of the imager372(or472).

Similarly, with particular reference toFIG. 12, an image of the item20captured in the view volume360(or460) is propagated through the scan window330along a first image path segment360a(or460a). First image path segment360a(or460a) is reflected sidewardly by the second mirror346along a second image path segment360b(or460b) to the first mirror344, which reflects the image forwardly (i.e., toward the scan window330) along a third image path segment360c(or460c) toward a second mirror portion340of the split mirror338. The second mirror portion340reflects a fourth image path segment360d(or460d) rearwardly (i.e., toward the PCB332) to the fourth mirror336, which reflects a fifth image path segment360e(or460e) forwardly to the fifth mirror334, which reflects the image along a sixth image path segment360f(or460f) to the imager372(or472) supported on the PCB332. The image may be focused by a suitable focusing lens374(or474) positioned in front of the imager372(or472).

FIG. 13is a partially exploded view of the portal scanner100and bottom scanner50ofFIG. 3illustrating an object measurement system500that uses dead reckoning to track a position of items20as they pass through the read region150. The object measurement system500includes a height light curtain505(for determining a height and length of the item20passing therethrough) and a lateral light curtain510(for determining the lateral position and width of the item20on the conveyor14). In some embodiments, the height light curtain505is formed by sensor elements515positioned vertically on each of the leg sections120,130, preferably in an aligned configuration (e.g., with pairs of sensors facing one another from the leg sections120,130). Similarly, lateral light curtain510is formed by sensor elements520positioned horizontally across the top section110and the bottom scanner50. The portal scanner100may be positioned on the checkstand5so that the top section110is centered above the gap18and the sensor elements520on the top section110are aligned with corresponding sensor elements520on the bottom scanner50to form the lateral light curtain510without interruption by the conveyors15,16.

When an item passes through the light curtains505,510certain ones of the sensor elements515,520are blocked depending on the height of the item20, the length of the item20, the lateral position of the item20, and the width of the item20on the conveyor15. Multiple reads of the light curtains505,510provide light curtain data corresponding to a vertical object sensor (VOS) profile that represents the height and longitudinal length of the item20and a lateral object sensor (LOS) profile that represents the width and lateral position on the conveyor14of the item20. The VOS and LOS profiles may be combined by the object measurement system to produce model data representing a three-dimensional model of the item.

When an item20is scanned and decoded, the model data (produced as described above) is combined with the timing and trajectory of the detected barcode to correlate barcode data with the three-dimensional model of the item at an estimated item position. This correlation between the combination of the timing and trajectory as detected allows the portal scanner to differentiate between multiple reads of the same item, and distinguish identical labels on multiple items. Dead reckoning may also allow the software to determine the presence of multiple distinct labels on individual items (such as an overpack label for a multi-pack of items). Additional details of an example object measurement system with timing and trajectory, three dimensional model creation, and related software are further described in U.S. App. Pub. No. 2013/0020391, hereby incorporated by reference.

As illustrated inFIG. 13, in some embodiments, the portal scanner100provides an arrangement of eight data readers, with four data readers145in the top section110and two data readers140in each of the leg sections120,130. Each of the data readers140,145may include one or more cameras for capturing images of the item20. In one embodiment, the data readers145in the top section110are arranged side-by-side in a single row to capture images in both the forward and rearward directions as the item20passes through the portal scanner100. Similarly, the data readers140in the leg sections120,130are arranged in a stacked configuration or column with one data reader stacked on top of the other. In such embodiments, the compact arrangement of data readers140,145provides for a lean design, with the top section110, and the leg sections120,130each having a width that may range between 25 cm to 30 cm. The optional bottom scanner50may further include four data readers for a combined total of twelve data readers in the automated checkout system10.

In other embodiments, the leg sections120,130may each only include one data reader for a combined total of 10 data readers in the automated checkout system10. In still other embodiments, the portal scanner100and bottom reader50may provide an arrangement for a different number of data readers depending on the size of the portal scanner100and the automated checkout system5. For example, with reference toFIG. 14, the automated checkstand10may include a portal scanner100with a small profile to fit a conveyor (e.g. conveyors15,16ofFIG. 1) having a 12-inch width. In such embodiments, the portal scanner100may include six total data readers, with two data readers each on the top section110and bottom scanner50, and one data reader on each of the leg sections120,130. In other embodiments, the portal scanner100can accommodate any number and arrangement of data readers as desired.

FIG. 15illustrates an exemplary system architecture600for processing captured data. Images from the cameras are decoded and the decoded information are sent to an interconnect processor610. Light curtain information from the height and lateral light curtains505,510is processed and the corresponding information (light curtain state packets) is also sent to the interconnect processor610. The interconnect processor610applies time stamps to the packets and sends the time stamped packet data to the correlation processor612. The correlation processor612generates object models (e.g., three-dimensional models of objects) from the light curtain and lateral sensor packets and correlates object data with the decode packets to determine which objects correspond to the decoded data. Successfully correlated barcode information as well as exception data is then transmitted to the POS host. Exception data corresponds to any number of events when the object models and decode packets indicate that an error may have occurred. Examples of exceptions include, but are not limited to: (a) more than one barcode is correlated with an object; and (2) no barcode is correlated with an object model; (3) a barcode is read but is not correlated with an object model. Additional details of exceptions and exception handling methods are further described in U.S. App. Pub. No. 2013/0020391.

It is intended that subject matter disclosed in portion herein can be combined with the subject matter of one or more of other portions herein as long as such combinations are not mutually exclusive or inoperable. In addition, many variations, enhancements and modifications of the imager-based optical code reader concepts described herein are possible.

The terms and descriptions used above are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that many variations can be made to the details of the above-described embodiments without departing from the underlying principles of the invention.