Patent Publication Number: US-9415935-B1

Title: Automated inventory quality control

Description:
BACKGROUND 
     Modern inventory systems face increasing demands to efficiently fulfill orders despite increasing complexity and diversity of inventories and orders. Inventory systems, however, often suffer from misplaced, missing, or otherwise incorrect inventory that may lower system throughput, cause unfinished or delayed tasks, and result in unacceptable response times. For example, a certain inventory item may be placed in a wrong location and thus may not be located in order to fulfill an order. As another example, a worker may remove an incorrect inventory item from a location when attempting to fulfill an order. Accordingly, inventory systems face the challenge of effectively controlling inventory in order to meet rising demands. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and its features and advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  illustrates an example system for providing automated inventory quality control, according to certain embodiments of the present disclosure; 
         FIG. 2  illustrates capturing an image of the inventory of an inventory holder of the example system of  FIG. 1 , according to certain embodiments of the present disclosure; 
         FIGS. 3A and 3B  illustrate a physical inventory and a virtual inventory of an inventory holder of the example system of  FIG. 1 , according to certain embodiments of the present disclosure; 
         FIG. 4  illustrates an example method for providing automated inventory quality control, which may be performed by the example system of  FIG. 1  according to certain embodiments of a present disclosure; 
         FIG. 5  illustrates another example method for providing automated inventory quality control, which may be performed by the example system of  FIG. 1  according to certain embodiments of a present disclosure; 
         FIG. 6  illustrates another example method for providing automated inventory quality control, which may be performed by the example system of  FIG. 1  according to certain embodiments of a present disclosure; and 
         FIG. 7  illustrates an example computer system that may be used for one or more portions of the example system of  FIG. 1 , according to certain embodiments of the present disclosure. 
     
    
    
     DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Inventory systems are utilized by many entities for storing and managing inventory. For example, some retailers may utilize a warehouse of racks that store inventory items in various bins. When an order for a specific inventory item needs to be filled by the retailer, a worker typically retrieves the inventory item from the bin where the inventory item is stored. 
     Typical inventory systems face many quality control challenges due to human interaction with the inventory. For example, an inventory item may be placed in an incorrect bin by a worker when it is being stocked or after it has been returned by a customer. As another example, a worker may remove an incorrect inventory item from a rack of bins when an order is being filled. As yet another example, a retailer may be the victim of theft in which inventory items are removed from bins without the retailer&#39;s knowledge. These and other inventory quality control issues are undesirable because they may reduce system throughput, increase costs, and result in unacceptable response times. 
     Certain embodiments of the present disclosure provide automated inventory quality control by utilizing robotics and imaging to detect the inventory of an inventory holder. In certain embodiments, one or more images of the inventory of an inventory holder are utilized to detect discrepancies between a physical inventory and a virtual inventory. In other embodiments, one or more images of the inventory of an inventory holder are utilized to detect whether a worker has picked the correct inventory items according to an order. Thus, the disclosed embodiments are able to detect and flag inventory quality control issues so they may be remedied.  FIGS. 1 through 7  below illustrate systems and methods for providing automated inventory quality control according to certain embodiments of the present disclosure. 
       FIG. 1  illustrates an inventory system  100  for automated inventory quality control using robotics and imaging. System  100  includes a workspace  105 , one or more image capture devices  110 , one or more mobile drive units  120 , one or more inventory holders  130 , and a picking station  150 . Mobile drive units  120  are communicatively coupled to a management module  160 . Inventory holders  130  are stored in an array of inventory holders  135 . Image capture devices  110  are located in or in close proximity to image capture zones  125 . 
     In general, mobile drive units  120  deliver inventory holders  130  to various locations within workspace  105 . For example, mobile drive unit  120  may retrieve an inventory holder  130  and deliver the inventory holder  130  to a picking station  150 . At picking station  150 , a worker  170  may remove inventory items from inventory holder  130  according to an electronic order  145 . The picked inventory items from inventory holder  130  may constitute a picked order  140 . Picked order  140  may be placed in order holder  144  where it may ultimately be shipped or otherwise provided to a customer. 
     Mobile drive unit  120  may also deliver inventory holders  130  to one or more image capture zones  125  within workspace  105  where imaging may be utilized for automated inventory quality control. For example, mobile drive unit  120  may deliver inventory holder  130  to an image capture zone  125  where an image capture device  110  utilizes an image capture process  115  to capture one or more images  118  of the inventory stored in inventory holder  130 . The one or more images  118  captured while inventory holder  130  is located within image capture zone  125  may be utilized to determine whether the inventory in inventory holder  130  is correct. In one example, the one or more images  118  captured from inventory holder  130  while it is located within image capture zone  125  may be utilized to determine any discrepancies between the physical inventory of inventory holder  130  and a virtual inventory associated with inventory holder  130 . In another example, the one or more images  118  captured from inventory holder  130  while it is located within image capture zone  125  may be utilized to determine whether the correct inventory items for electronic order  145  were removed from inventory holder  130 . 
     Workspace  105  represents an area associated with inventory system  100  in which mobile drive units  120  can move and/or inventory holders  130  can be stored. For example, workspace  105  may represent all or part of the floor of a mail-order warehouse in which inventory system  100  operates. Although  FIG. 1  shows, for the purposes of illustration, an embodiment of inventory system  100  in which workspace  105  includes a fixed, predetermined, and finite physical space, particular embodiments of inventory system  100  may include mobile drive units  120  and inventory holders  130  that are configured to operate within a workspace  105  that is of variable dimensions and/or an arbitrary geometry. While  FIG. 1  illustrates a particular embodiment of inventory system  100  in which workspace  105  is entirely enclosed in a building, alternative embodiments may utilize workspaces  105  in which some or all of the workspace  105  is located outdoors, within a vehicle (such as a cargo ship), or otherwise unconstrained by any fixed structure. 
     Moreover, in particular embodiments, workspace  105  may include multiple portions that are physically separated from one another, including but not limited to separate floors, rooms, buildings, and/or portions divided in any other suitable manner. Mobile drive units  120  may be configured to utilize alternative conveyance equipment such as vertical or horizontal conveyors, trucks, ferries, gondolas, escalators, and/or other appropriate equipment suitable to convey mobile drive units  120  between separate portions of workspace  105 . 
     Image capture device  110  may be any appropriate device for capturing images  118  of the inventory of inventory holder  130 . In one embodiment, image capture device  110  is a video camera. For example, image capture device  110  may be a high-definition video camera that captures images  118  in the form of a high-definition video data stream of inventory holder  130  while it is located in or while it passes through image capture zone  125 . In another embodiment, image capture device  110  may be any appropriate camera that captures still images. For example, image capture device  110  may be a high-definition camera that captures one or more still images  118  of inventory holder  130  while it is located in or while it passes through image capture zone  125 . While particular examples of image capture device  110  have been discussed, the disclosure is not limited to any particular type or form of image capture device. 
     Image capture device  110  utilizes an image capture process  115  for capturing one or more images  118  of inventory holder  130 . In certain embodiments, image capture process  115  may refer to capturing a single still image  118  of inventory holder  130  while it is stationary inside image capture zone  125  or as inventory holder  130  is passing through image capture zone  125 . In another embodiment, image capture process  115  may refer to capturing multiple images  118  of inventory holder  130  while it is stationary inside image capture zone  125  or as inventory holder  130  is passing through image capture zone  125 . For example, multiple still images  118  or multiple images in the form of video data may be captured of inventory holder  130  while it is stationary inside image capture zone  125  or as inventory holder  130  is passing through image capture zone  125 . 
     Image capture zone  125  is any location within workspace  105  where image capture device  110  captures one or more images  118  of the inventory stored in inventory holder  130 . For example, workspace  105  may include three image capture zones  125   a - 125   c . Image capture zone  125   a  may be a location that inventory holder  130  passes through after departing array  135  but before arriving at picking station  150 . Image capture zone  125   b  may be a location that is proximate to or inside picking station  150 . Image capture zone  125   c  may be a location that inventory holder  130  passes through after departing from picking station  150  but before being returned to array  135 . In some embodiments, image capture zones  125   a  and  125   b  may be the same image capture zone  125 . That is, mobile drive unit  120  may deliver inventory holder  130  through a particular image capture zone  125  such as image capture zone  125   a  both before arriving at picking station  150  and after departing picking station  150 . While the illustrated embodiment of  FIG. 1  includes three image capture zones  125 , the disclosure anticipates workspace  105  including only a single image capture zone  125  or any appropriate number of image capture zones  125 . 
     Mobile drive units  120  represent any suitable combination of devices and components operable to move inventory holders  130  and/or order holders  144  within workspace  105 . Mobile drive units  120  may be designed to couple, interface, dock or otherwise connect with inventory holders  130  and/or order holders  144 . For example, mobile drive units  120  may be configured to move beneath a given inventory holder  130  and/or order holder  144  and lift the holder using a docking head  122  or other appropriate coupling structure. Mobile drive units  120  include one or more wheels  124  and may be capable of moving to any appropriate location within workspace  105 . 
     Mobile drive units  120  may include appropriate communication devices to communicate information to and from management module  160 , other mobile drive units  120 , and/or picking stations  150 . In some embodiments, mobile drive units  120  may communicate with management module  160  and/or other mobile drive units  120  using Wi-Fi (IEEE 802.11), Bluetooth (IEEE 802.15), Infrared Data Association standards, or any other appropriate wireless communications protocol. Mobile drive units  120  may include appropriate sensors to detect fixed locations and/or other mobile drive units  120  within workspace  105 . Mobile drive units  120  may thereby facilitate movement and/or avoid collisions. Mobile drive units  120  may communicate information to management module  160  to assist management module  160  in the management of inventory system  100 . For example, mobile drive unit  120  may transmit its location relative to a fixed location within workspace  105  to management module  160 . In some embodiments, mobile drive units  120  represent independent self-powered robotic devices. Alternatively or in addition, mobile drive units  120  may represent multiple types of mobile drive units. Mobile drive units  120  in various embodiments may refer to any appropriate means of transporting inventory items  130  to locations within workspace  105 . For example, mobile drive units  120  may refer to conveyance systems that make use of conveyor belts, cranes, or other apparatus to move inventory items and/or inventory holders  130  within workspace  105 . 
     Inventory holders  130  store inventory items. In some embodiments, inventory holders  130  include multiple storage bins each capable of holding one or more inventory items. Alternatively or in addition, inventory holders  130  may include a rack of shelves, each shelf capable of carrying one or more inventory items. Inventory holders  130  are capable of coupling and/or docking with mobile drive units  120  and being carried, rolled, or otherwise moved by mobile drive units  120 . Inventory holder  130  may include a plurality of faces. Each bin of inventory holder  130  may be accessible through one or more faces of the inventory holder  130 . For example, in some embodiments, inventory holder  130  may include four faces, and mobile drive unit  120  may be operable to rotate inventory holder  130  at appropriate times within workspace  105  to present a particular face containing the inventory items needed at picking station  150 . A particular embodiment of inventory holder  130  is discussed further below in reference to  FIG. 2 . 
       FIG. 2  illustrates an example of image capture device  110  capturing one or more images  118  of inventory holder  130  while it is located in an image capture zone  125 . Image capture device  110  is communicatively coupled to a computing system  210 . Computing system  210  is communicatively coupled to picking station  150  and one or more storage devices  230 . Image capture device  110  utilizes image capture process  115  as described above to capture one or more images  118  of the inventory of inventory holder  130 . A particular embodiment of computing system  210  is described further below in reference to  FIG. 7 . 
       FIG. 2  also illustrates in greater detail the components of a particular embodiment of inventory holder  130 . In particular,  FIG. 2  illustrates the structure and contents of one side of an example inventory holder  130 . In a particular embodiment, inventory holder  130  may comprise any number of faces with similar or different structure. As illustrated, inventory holder  130  includes a frame  132 , a plurality of legs  133 , and a docking surface  123 . 
     Frame  132  holds inventory items  250 . Frame  132  provides storage space for storing inventory items  250  external or internal to frame  132 . The storage space provided by frame  132  may be divided into a plurality of inventory bins  134 , each capable of holding inventory items  250 . Inventory bins  134  may include any appropriate storage elements, such as bins, compartments, or hooks. 
     In a particular embodiment, frame  132  is composed of a plurality of trays  136  stacked upon one another and attached to or stacked on a base. In such an embodiment, inventory bins  134  may be formed by a plurality of adjustable dividers  138  that may be moved to resize one or more inventory bins  134 . In alternative embodiments, frame  132  may represent a single inventory bin  134  that includes a single tray  136  and no adjustable dividers  138 . Inventory items  250  may be stored on such an inventory holder  130  by being placed on frame  132 . In general, frame  132  may include storage internal and/or external storage space divided into any appropriate number of inventory bins  134  in any appropriate manner. 
     Additionally, in a particular embodiment, frame  132  may include a plurality of device openings that allow mobile drive unit  120  to position docking head  122  adjacent to docking surface  123 . The size, shape, and placement of the device openings of inventory holder  130  may be determined based on the size, the shape, and other characteristics of the particular embodiment of mobile drive unit  120  and/or inventory holder  130  utilized by inventory system  100 . For example, in the illustrated embodiment, frame  132  includes four legs  133  that form a device opening and allow mobile drive unit  120  to position itself under frame  132  and adjacent to docking surface  123 . The length of legs  133  may be determined based on a height of mobile drive unit  120 . 
     Docking surface  123  comprises a portion of inventory holder  130  that couples to, abuts, and/or rests upon a portion of docking head  122 , when mobile drive unit  120  is docked to inventory holder  130 . Additionally, docking surface  123  supports a portion or all of the weight of inventory holder  130  while inventory holder  130  is docked with mobile drive unit  120 . The composition, shape, and/or texture of docking surface  123  may be designed to facilitate maneuvering of inventory holder  130  by mobile drive unit  120 . For example, as noted above, in particular embodiments, docking surface  123  may comprise a high-friction portion. When mobile drive unit  120  and inventory holder  130  are docked, frictional forces induced between docking head  122  and this high-friction portion may allow mobile drive unit  120  to maneuver inventory holder  130 . Additionally, in particular embodiments, docking surface  123  may include appropriate components suitable to receive a portion of docking head  122 , couple inventory holder  130  to mobile drive unit  120 , and/or facilitate control of inventory holder  130  by mobile drive unit  120 . 
     Inventory items  250  may be any item of any form that may be stored in inventory holder  130 . As examples for illustrative purposes only, inventory items  250  may be any form of electronics, household goods, grocery items, any form of media such as books, movies, or music, or any other appropriate item. Some embodiments of inventory items  250  may include a barcode  255  that is located on the outside of inventory item  250  or packaging of inventory item  250 . Barcode  255  may be any type of transaction code. For example, barcode  255  may be in the form of a linear bar code (or a one-dimensional bar code), such as a code  93 , a code  128 , or a universal product code (UPC); a matrix bar code (or a two dimensional bar code), such as a quick response (QR) code, a MaxiCode, or a ShotCode; an RFID code; a sequence of numbers and/or symbols; any other transaction code; or any combination of the preceding. Barcode  255  may include any information that allows inventory item  250  to be identified. 
     Returning to  FIG. 1 , picking station  150  represents one or more locations designated for the completion of particular tasks involving inventory items  250 . Such tasks may include the removal of inventory items  250  from inventory holders  130 , the introduction of inventory items  250  into inventory holders  130 , the counting of inventory items  250  in inventory holders  130 , the decomposition of inventory items  250  (e.g. from pallet- or case-sized groups to individual inventory items), and/or the processing or handling of inventory items  250  in any other suitable manner. In particular embodiments, picking station  150  may just represent the physical locations where a particular task involving inventory items  250  can be completed within workspace  105 . In alternative embodiments, picking station  150  may represent both the physical location and also any appropriate equipment for processing or handling inventory items, such as scanners for monitoring the flow of inventory items in and out of inventory system  100 , communication interfaces for communicating with management module  160  and/or computing system  210 , and/or any other suitable components. Picking station  150  may be controlled, entirely or in part, by human operators or may be fully automated. Moreover, the human or automated operators of picking station  150  may be capable of performing certain tasks to inventory items, such as packing or counting inventory items  250 , as part of the operation of inventory system  100 . 
     Order holders  144  store picked order  140 . For example, order holders  144  may represent various pallets, bins, receptacles, tables, conveyors, and/or other structures capable of holding and/or storing picked order  140 . In some embodiments, order holders  144  may be an inventory holder  130  that is designated to store picked order  140 . Order holders  144  may store picked order  140  until those orders are ready to be shipped. In some embodiments, order holders  144  may themselves be loaded for shipment. For example, order holders  144  may be shipping containers, pallets, or other receptacles suitable for shipment. Order holders  144  may simply hold picked order  140  until those orders are ready to be removed from order holders  144  for shipment. Alternatively or in addition, order holders  144  may store orders received by inventory system  100  that may be filled from inventory holders  130  at picking station  150 . 
     In some embodiments, order holders  144  are substantially similar to inventory holders  130 . For example, in some embodiments, inventory holders  130  may be designated as order holders  144  by management module  160 . Moreover, a particular component may at different times serve as an inventory holder  130 . In some embodiments, a component may serve simultaneously as both an inventory holder  130  and an order holder  144  by storing both inventory items  250  and picked order  140 . In some embodiments, order holders  144  may be capable of storing, holding and/or enclosing shipping containers such as boxes, pallets, or other shipping containers in which orders can be delivered to a given destination. In some embodiments, order holders  144  may not include bins or partitions and may instead hold only a single picked order  140  or group of picked orders  140  that are stored in mass. For example, order holder  144  may support, include or represent a pallet in which one or more orders are stored. Moreover, in particular embodiments, order holder  144  may represent a shipping container on or in which stored picked orders  140  may be shipped. 
     Management module  160  represents any suitable combination of hardware, software, and controlling logic operable to coordinate the operation of various components within system  100 . In some embodiments, management module  160  may include one or more processors, one or more memory modules, and one or more communication interfaces. Logic may be encoded on one or more non-transitory computer-readable media and may be executed by the one or more processors. Management module  160  may include logic to schedule and execute various tasks involving the movement and processing of inventory items within system  100 . For example, management module  160  may assign tasks to mobile drive units  120  and/or picking station  150 . Management module  160  may include logic to facilitate coordination of the movement of mobile drive units  20  within workspace  105  in order to complete the assigned tasks. Management module  160  may include one or more communication interfaces to send information to and receive information from mobile drive units  120  and/or computing system  210 . For example, management module  160  may transmit, to one or more mobile drive units  120 , task assignment information, destination information, path planning information, reservation information, and/or any other appropriate information. It should be noted that while management module  160  is depicted as a separate component within inventory system  100 , the functionality performed by management module  160  may be distributed over several devices. For example, the operations of management module  160  may be performed by mobile drive units  120  and/or other appropriate components of inventory management system  100  such as computing system  210 . As a result, any or all of the interaction between a particular mobile drive unit  120  and management module  160  that is described herein may, in particular embodiments, represent peer-to-peer communication between mobile drive units  120 . 
     Management module  160  may determine one or more inventory items responsive to electronic order  145  for one or more inventory items  250 . Management module  160  may determine which inventory holders  130  store those inventory items  250 . Management module  160  may then assign tasks to transport those inventory holders  130  to one or more image capture zone  125  and/or picking station  150 . Inventory holders  130  may transport inventory items needed to complete electronic order  145 . Based on their respective task assignments, mobile drive units  120  may transport the inventory holders  130  with inventory items  250  responsive to electronic order  145  to picking station  150 . 
     Referring to  FIG. 1  in conjunction with  FIG. 2 , in operation of example embodiments, mobile drive unit  120  delivers inventory holder  130  from array  135  first to image capture zone  125   a  and then to picking station  150  where inventory item  250  may be removed according to electronic order  145 . While inventory holder  130  is located in (e.g., either stationary or passing through) image capture zone  125   a , image capture device  110   a  captures one or more images  118   a  of inventory items  250  located in inventory holder  130 . The captured images  118   a  may be transmitted to computing system  210  where an application  220  may analyze the captured one or more images  118   a  in order to determine any quality control issues with inventory holder  130 . For example, application  220  may analyze captured images  118   a  to determine a physical inventory of inventory holder  130 . Application  220  may also access a virtual inventory  240  associated with inventory holder  130  and compare the virtual inventory  240  with the determined physical inventory. As a result, application  220  may detect discrepancies between virtual inventory  240  and the determined physical inventory of inventory holder  130 . Particular embodiments of the determined physical inventory of inventory holder  130  and virtual inventory  240  are illustrated further below in reference to  FIGS. 3A-3B . 
     Mobile drive unit  120  may also deliver inventory holder  130  to image capture zone  125   b  that is proximate to or inside picking station  150 . In some embodiments, mobile drive unit  120  delivers inventory holder  130  to image capture zone  125   b  after passing through image capture zone  125   a . In other embodiments, mobile drive unit  120  delivers inventory holder  130  to image capture zone  125   b  directly from array  135 . While located in (e.g., while stationary in or passing through) image capture zone  125   b , image capture device  110   b  captures one or more images  118   b  of inventory items  250  located in inventory holder  130 . 
     The captured images  118   b  may be transmitted to computing system  210  where an application  220  may analyze the captured one or more images  118   b  in order to determine any quality control issues with inventory holder  130 . For example, application  220  may analyze captured images  118   b  to determine whether the correct inventory item(s)  250  have been removed from inventory holder  130  according to electronic order  145 . This may be accomplished in any appropriate manner. In one example, application  220  may analyze an image  118   a  associated with each inventory item  250  that is removed from inventory holder  130  and compare it with electronic order  145 . If the removed inventory item  250  is not included in electronic order  145 , an indication (e.g., visual, audible, etc.) may be presented to worker  170  in picking station  150 . 
     In another example, application  220  may analyze a first image  118   a  taken when inventory holder  130  first arrived at image capture zone  125   b  and a second image  118   a  taken after worker  170  completes his/her interaction with inventory holder  130 . Application  220  may then determine from the analyzed images a physical inventory of inventory holder  130  before worker  170  interacts with inventory holder  130  and a physical inventory of inventory holder  130  after worker  170  interacts with inventory holder  130 . Application  220  may determine, by comparing these two determined physical inventories and electronic order  145 , whether correct inventory item(s)  250  have been removed from inventory holder  130 . Example embodiments of determining inventory of inventory holder  130  from images  118  are discussed further below. 
     Mobile drive unit  120  may also deliver inventory holder  130  to image capture zone  125   c  after departing from picking station  150  but before arriving at array  135 . As mentioned above, image capture zone  125   c  may be image capture zone  125   b  in some embodiments. While inventory holder  130  is located in (e.g., either stationary or passing through) image capture zone  125   c , image capture device  110   c  captures one or more images  118   c  of inventory items  250  located in inventory holder  130 . The captured images  118   c  may be transmitted to computing system  210  where application  220  may analyze the captured one or more images  118   c  in order to determine any quality control issues with inventory holder  130 . In one embodiment, a physical inventory of inventory holder  130  is determined from images  118   c  and compared to a physical inventory of inventory holder  130  determined from images  118   b  captured in image capture zone  125   a . As such, discrepancies in the inventory of inventory holder  130  due to mistakes by worker  170  in picking station  150  may be discovered. Determining discrepancies in the inventory of inventory holder  130  are discussed further below in reference to  FIGS. 3A and 3B . 
     Some embodiments may additionally determine a cause and/or time associated with discrepancies in the inventory of inventory holder  130 . As one example, if discrepancies are determined in an image capture zone  125   a  that is before picking station  150 , it may be determined that the discrepancies are not associated with interactions with inventory holder  130  by worker  170 . As another example, if discrepancies are determined in an image capture zone  125   c  that is after picking station  150 , it may be determined that the discrepancies are due to interactions with inventory holder  130  by worker  170 . For example, worker  170  may have incorrectly removed inventory items  250  from or incorrectly placed inventory items  250  into inventory holder  130 . 
     In some embodiments, application  220  may determine whether theft was the cause of discrepancies in the inventory of inventory holder  130 . For example, application  220  may access images  118   c  captured before inventory holder  130  was delivered to array  135  and images  118   a  captured after inventory holder  130  was removed from array  135 . Application  220  may then determine physical inventories from images  118   c  and  118   a  and determine whether any discrepancies exist. If discrepancies exist, application  220  may determine that inventory items  250  were removed from inventory holder  130  while is was at a storage location within array  135 . In some embodiments, application  220  may determine the previous storage location of inventory holder  130  and access surveillance video of the storage location. In some embodiments, application  220  may analyze the surveillance video in order to determine a time when the theft occurred. For example, application  220  may utilize motion detection on the surveillance video of the storage location to determine a time when a person was in the vicinity of the storage location. 
     In certain embodiments, various actions may be taken in response to determining that discrepancies exist between the physical inventory and virtual inventory of inventory holder  130 . In some embodiments, application  220  may transmit a message indicating the discrepancies. For example, an email message may be transmitted to a loss prevention department. In some embodiments, a visual or audible indication may be presented. For example, a visual indication of inventory discrepancies may be displayed to worker  170  in picking station  150 . 
     In certain embodiments, inventory holder  130  may be placed in quarantine in response to a determination that discrepancies in inventory exist. For example, inventory holder  130  may be delivered via mobile drive unit  120  to a troubleshooting station. In some embodiments, the troubleshooting station may be another picking station  150 . At the troubleshooting station, the discrepancies may be highlighted and/or displayed so that worker  170  may analyze and/or remediate the discrepancies. In embodiments where an inventory holder  130  is delivered to a troubleshooting station, another inventory holder  130  may be retrieved from array  135  and delivered to picking station  150  instead of the original inventory holder  130 . In other embodiments, the inventory holder  130  with inventory discrepancies may be delivered first to picking station  150  where worker  170  may be permitted to proceed with picking inventory items  250  to fulfill electronic order  145 . Then, after order  145  is fulfilled, the inventory holder  130  may then be delivered to the troubleshooting station for inventory analysis. 
       FIGS. 3A and 3B  illustrate example embodiments of a physical inventory  310  and a virtual inventory  240  of inventory holder  130 . Physical inventory  310  may be determined, for example, by application  220  analyzing one or more images  118 . Examples of how application  220  may determine physical inventory  310  using one or more images  118  are discussed further below. Virtual inventory  240  may be stored, for example, in one or more storage devices  230  accessible to computing system  210 . In some embodiments, virtual inventory  240  may be associated with a single inventory holder  130  and may be a portion of a master inventory list of multiple inventory holders  130 . 
     As discussed above, image capture device  110  utilizes image capture process  115  to capture one or more images  118  of inventory holder  130  while it is in image capture zone  125 . Using the captured one or more images  118 , application  220  may determine physical inventory  310  of inventory holder  130  using any appropriate method. While three example methods of determining physical inventory  310  of inventory holder  130  from image(s)  118  are discussed below, any appropriate method may be utilized. The disclosure is not limited to the three example methods below. In addition, any combination of the three example methods below may be utilized to determine physical inventory  310  of inventory holder  130 . 
     In a first embodiment, application  220  may determine physical inventory  310  of inventory holder  130  from image(s)  118  by analyzing exposed barcodes  255  of inventory items  250  located in inventory holder  130 . For example, application  220  may analyze image(s)  118  in order to isolate and possibly enhance images of the captured exposed barcodes  255 . Application  220  may then utilize any appropriate scanning technique to analyze each barcode  255  and determine from the barcode  255  information about the specific inventory item  250  associated with the barcode  255 . For example, application  220  may determine a product code from barcode  255  and consult a database of known products. From this, application  220  may determine, for example, a product name associated with the specific inventory item  250 . In addition, application  220  may determine a quantity of each type of inventory item  250  using barcodes  255 . As a result, application  220  may determine physical inventory  310  of inventory holder  130  from barcode(s)  255  found in image(s)  118 . 
     In a second embodiment, application  220  may determine physical inventory  310  of inventory holder  130  from image(s)  118  by utilizing optical character recognition. For example, application  220  may analyze image(s)  118  in order to isolate and possibly enhance images of individual inventory item(s)  250 . Application  220  may then utilize any appropriate optical character recognition technique to determine information about the specific inventory item  250 . For example, application  220  may isolate an image of a book that is stored in inventory holder  130 . From this, application  220  may utilize optical character recognition to determine, for example, a title of the book, an International Standard Book Number (ISBN) of the book, and the like. In some embodiments, application  220  may utilize any determined characters to consult a database of known products and determine a product name associated with the specific inventory item  250 . In addition, application  220  may determine a quantity of each type of inventory item  250  using the determined characters. As a result, application  220  may determine physical inventory  310  of inventory holder  130  using optical character recognition of image(s)  118 . 
     In a third embodiment, application  220  may determine physical inventory  310  of inventory holder  130  from image(s)  118  by comparing image(s)  118  to known product images. For example, application  220  may analyze image(s)  118  in order to isolate and possibly enhance images of individual inventory item(s)  250 . Application  220  may then compare image(s)  118  to a database of known product images. From this, application  220  may determine a product name associated with the specific inventory item  250 . In addition, application  220  may determine a quantity of each type of inventory item  250  using the comparison of images. As a result, application  220  may determine physical inventory  310  of inventory holder  130  by comparing image(s)  118  to known product images. 
     As an example for illustrative purposes only, consider the illustrated physical inventory  310  of  FIG. 3A . In this embodiment, application  220  determined physical inventory  310  using any one or combination of the methods described above. As illustrated in  FIG. 3A , physical inventory  310  of an inventory holder  130  designated “INVENTORY HOLDER #1” includes three inventory bins  134 : “INVENTORY BIN #1,” “INVENTORY BIN #2,” and “INVENTORY BIN #3.” “INVENTORY BIN #1” was found to include two units of “ITEM A” and three units of “ITEM 3.” “INVENTORY BIN #2” was found to include ten units of “ITEM A.” “INVENTORY BIN #3” was found to include five units of “ITEM C.” 
     Virtual inventory  240  of  FIG. 3A  likewise is associated with “INVENTORY HOLDER #1” and includes three inventory bins  134 : “INVENTORY BIN #1,” “INVENTORY BIN #2,” and “INVENTORY BIN #3.” According to virtual inventory  240 , “INVENTORY BIN #1” should include two units of “ITEM A” and three units of “ITEM 3,” “INVENTORY BIN #2” should include ten units of “ITEM A,” and “INVENTORY BIN #3” should include five units of “ITEM C.” 
     As illustrated in  FIG. 3A , physical inventory  310  of “INVENTORY HOLDER #1” is identical to virtual inventory  240  of “INVENTORY HOLDER #1.” Thus, application  220  determines that there are no discrepancies between physical inventory  310  and virtual inventory  240 . On the other hand,  FIG. 3B  illustrates an embodiment where application  220  determines that there are discrepancies between physical inventory  310  and virtual inventory  240 . As illustrated in  FIG. 3B , physical inventory  310  of an inventory holder  130  designated “INVENTORY HOLDER #1” includes three inventory bins  134 : “INVENTORY BIN #1,” “INVENTORY BIN #2,” and “INVENTORY BIN #3.” “INVENTORY BIN #1” was found to include two units of “ITEM A” and three units of “ITEM 3.” “INVENTORY BIN #2” was found to include nine units of “ITEM A.” “INVENTORY BIN #3” was found to include five units of “ITEM C.” 
     Virtual inventory  240  of  FIG. 3A  likewise is associated with “INVENTORY HOLDER #1” and includes three inventory bins  134 : “INVENTORY BIN #1,” “INVENTORY BIN #2,” and “INVENTORY BIN #3.” According to virtual inventory  240 , “INVENTORY BIN #1” should include two units of “ITEM A” and three units of “ITEM 3,” “INVENTORY BIN #2” should include ten units of “ITEM A,” and “INVENTORY BIN #3” should include five units of “ITEM C.” 
     As illustrated in  FIG. 3B , physical inventory  310  of “INVENTORY HOLDER #1” is not identical to virtual inventory  240  of “INVENTORY HOLDER #1” because “INVENTORY BIN #2” was found to include nine units of “ITEM A” when virtual inventory  240  indicates it should include ten units. Thus, application  220  determines that there are discrepancies between physical inventory  310  and virtual inventory  240 . By catching discrepancies such as this in the inventory of inventory holder  130 , system  100  is able to improve quality control and thus improve throughput, response times, and customer satisfaction.  FIG. 4 through 6  below illustrate other embodiments of methods for automated inventory quality control. 
       FIG. 4  illustrates a method  400  for performing automated inventory quality control according to certain embodiments. Method  400  begins in step  410  where a mobile drive unit delivers an inventory holder to an image capture zone. For example, the mobile drive unit may refer to mobile drive unit  120  and the inventory holder may refer to inventory holder  130  discussed above. The image capture zone may refer to image capture zone  125  discussed above. In some embodiments, the inventory holder temporarily stops in the image capture zone. In some embodiments, the inventory holder merely passes through the image capture zone without stopping. 
     In step  420  an image is captured of the inventory in the inventory holder of step  410 . In some embodiments, an image capture device  110 , as discussed above, captures one or more images  118  of the inventory holder, as discussed above. In some embodiments, the captured image indicates some or all of the inventory located in the inventory holder. In some embodiments, the captured image includes more than one image such video data. In certain embodiments, the captured image includes one or more barcodes of the inventory located in the inventory holder. 
     In step  430  the images captured in step  420  are analyzed in order to determine the physical inventory of the inventory holder of step  410 . In one example, computing system  210 , utilizes one or more captured barcodes in the images captured in step  420  in order to determine the inventory of inventory holder  130 . In another example, optical character recognition may be utilized to determine the physical inventory of the inventory holder of step  410 . In yet another example, images of the inventory captured in step  420  may be compared to a database of known product images to determine the physical inventory of the inventory holder. 
     In step  440  a virtual inventory associated with the inventory holder of step  410  is accessed. In one embodiment, a master inventory is accessed in order to determine a virtual inventory for the inventory holder. For example, a master inventory of multiple inventory holders may be accessed from a storage device such as a database. In certain embodiments, the master inventory database may be analyzed in order to determine the virtual inventory associated with the inventory holder of step  410 . 
     In step  450  discrepancies are determined between the physical inventory of step  430  and the virtual inventory of step  440 . For example, the inventory items determined in step  430  may be compared to inventory items in step  440  in order to determine any discrepancies. In certain embodiments, any method described above may be utilized to determine the discrepancies in step  450 . If any discrepancies are determined in step  450 , method  400  may proceed to step  460 . Otherwise, method  400  may end. In step  460 , any discrepancies determined in step  450  may be reported. For example, a visual or audible indication of the discrepancies may be presented to worker  170  at picking station  150 . After step  460 , method  400  ends. 
       FIG. 5  illustrates one embodiment of a method  500  for automated inventory quality control. In this embodiment, images of an inventory holder are captured before and after a worker interacts with the inventory holder at a picking station. These images may be utilized, for example, to determine whether the worker in the picking station picks the correct inventory from and/or places the correct inventory in inventory holder  130 . 
     Method  500  begins in step  510  when an inventory holder is delivered to an image capture zone before the inventory holder is delivered to a picking station and/or before a worker begins interacting with the inventory holder. For example, a mobile drive unit  120  may deliver an inventory holder  130  to image capture zone  125   a  described above. As another example, a mobile drive unit  120  may deliver an inventory holder  130  to image capture zone  125   b  described above. 
     In step  520 , a first image is captured in the inventory holder while it is located in the image capture zone of  510 . In certain embodiments, the image is captured by an image capture device  110  described above. The first image captured in step  520  may indicate an inventory of the inventory holder before a worker interacts with the inventory holder at a picking station. 
     At step  530 , the first image captured in step  520  is analyzed in order to determine a physical inventory of the inventory holder before a worker interacts with the inventory holder. For example, methods such as analyzing exposed barcodes, utilizing optical character recognition, comparing the first image to a database of known product images, and/or any other suitable method may be used to determine the physical inventory of the inventory holder before a worker interacts with the inventory holder. 
     In step  540 , the inventory holder may be delivered to a picking station where a worker may interact with the inventory holder. For example, the worker may pick one or more items of inventory from the inventory holder according to an electronic order. In certain embodiments, the worker may place one or more items of inventory into the inventory holder. 
     In step  550 , the inventory holder is delivered to an image capture zone after the worker has interacted with the inventory holder at the picking station. In some embodiments, the image capture zone of  550  is the same image capture zone of step  510 . In other embodiments, the image capture zone of step  550  is different from the image capture zone of step  510 . 
     In step  560 , a second image is captured of the inventory in inventory holder while it is located in the image capture zone of step  550 . In certain embodiments, the image is captured by an image capture device  110  described above. The second image captured in step  560  may indicate an inventory of the inventory holder after a worker interacts with the inventory holder at a picking station. 
     In step  570 , the second image captured in step  560  is analyzed in order to determine a physical inventory of the inventory holder after the worker interacted with the inventory holder while it was located at the picking station. For example, methods such as analyzing exposed barcodes, utilizing optical character recognition, comparing the first image to a database of known product images, and/or any other suitable method may be used to determine the physical inventory of the inventory holder before a worker interacts with the inventory holder. 
     In step  580 , any discrepancies of the physical inventory of the inventory holder are determined. In one example, step  580  may include determining whether the worker at the picking station picked the correct inventory from the inventory holder. In one embodiment, items in an order may be subtracted from the physical inventory determined in step  530 . Once the items from an order have been subtracted from the physical inventory determined in step  530 , it may be compared to the physical inventory determined in step  570 . This may indicate whether the worker at the picking station picked the correct inventory from inventory holder. In another embodiment, step  580  may include determining inventory that was to be added to the inventory holder (e.g., for stocking purposes). Once the items that were to be stocked are added to the physical inventory determined in step  530 , a comparison may be made to the physical inventory determined in step  570 . This may indicate whether the worker at the picking station added the correct inventory to inventory holder. 
     If any discrepancies are determined in step  580 , method  500  may proceed to step  590 . Otherwise, method  500  may end. In step  590 , any discrepancies determined in step  580  may be reported. For example, a visual or audible indication of the discrepancies may be presented to worker  170  at picking station  150 . After step  590 , method  500  ends. 
       FIG. 6  illustrates one embodiment of a method  600  for automated inventory quality control. In this embodiment, images are captured while an inventory holder is located at a picking station. These images are utilized to determine whether a worker has picked the correct inventory from the inventory holder according to an order. Method  600  begins in step  610  where an inventory holder is delivered to a picking station. For example, a mobile drive unit  120  may deliver an inventory holder  130  to a picking station  150  as described above. 
     In step  620 , images are captured of the inventory in inventory holder while the inventory holder is at the picking station. In one example, images from video data may be analyzed to determine which inventory items are picked from and/or placed into the inventory holder. In another example, a first image is captured when the inventory holder is first delivered to the picking station and a second image is captured of the inventory of the inventory holder immediately before the inventory holder departs from the picking station. Differences between the first and second images may be compared below in step  630  to an order in order to determine whether a worker has picked the correct inventory from the inventory holder. In certain embodiments, differences between the first and second images may be compared in order to determine whether a worker has placed the correct inventory into the inventory holder 
     In step  630 , the images captured in step  620  of the inventory of the inventory holder are analyzed in order to determine which inventory items were picked from the inventory holder. Alternatively, the images captured of the inventory of the inventory holder are analyzed in order to determine which inventory items were placed into the inventory holder. Any appropriate method described above may be utilized in step  630  to determine the inventory picked from and/or placed into the inventory holder. 
     In step  640  an order is accessed. For example, electronic order  145  described above may be accessed. In step  650 , any discrepancies are determined between the order accessed in step  640  and the inventory picked from the inventory holder. In certain embodiments, if any discrepancies are determined, a visual or audible indication may be presented to the worker at the picking station. 
     If any discrepancies are determined in step  650 , method  600  may proceed to step  660 . Otherwise, method  600  may end. In step  660 , any discrepancies determined in step  650  may be reported. For example, a visual or audible indication of the discrepancies may be presented to worker  170  at picking station  150 . After step  660 , method  600  ends. 
       FIG. 7  illustrates an example computer system  700  that may be used for one or more portions of the systems and method disclosed herein. In particular embodiments, one or more computer systems  700  perform one or more steps of one or more methods described or illustrated herein. In particular embodiments, one or more computer systems  700  provide functionality described or illustrated herein, such as, for example, computing system  210 . In particular embodiments, software running on one or more computer systems  700  performs one or more steps of one or more methods described or illustrated herein or provides functionality described or illustrated herein. Particular embodiments include one or more portions of one or more computer systems  700 . 
     This disclosure contemplates any suitable number of computer systems  700 . This disclosure contemplates computer system  700  taking any suitable physical form. As example and not by way of limitation, computer system  700  may be an embedded computer system, a system-on-chip (SOC), a single-board computer system (SBC) (such as, for example, a computer-on-module (COM) or system-on-module (SOM)), a desktop computer system, a laptop or notebook computer system, an interactive kiosk, a mainframe, a mesh of computer systems, a mobile telephone, a personal digital assistant (PDA), a server, a tablet computer system, or a combination of two or more of these. Where appropriate, computer system  700  may include one or more computer systems  700 ; be unitary or distributed; span multiple locations; span multiple machines; span multiple datacenters; or reside in a cloud, which may include one or more cloud components in one or more networks. Where appropriate, one or more computer systems  700  may perform without substantial spatial or temporal limitation one or more steps of one or more methods described or illustrated herein. As an example and not by way of limitation, one or more computer systems  700  may perform in real time or in batch mode one or more steps of one or more methods described or illustrated herein. One or more computer systems  700  may perform at different times or at different locations one or more steps of one or more methods described or illustrated herein, where appropriate. 
     In particular embodiments, computer system  700  includes a processor  702 , memory  704 , storage  706 , an input/output (I/O) interface  708 , a communication interface  710 , and a bus  712 . Although this disclosure describes and illustrates a particular computer system having a particular number of particular components in a particular arrangement, this disclosure contemplates any suitable computer system having any suitable number of any suitable components in any suitable arrangement. 
     In particular embodiments, processor  702  includes hardware for executing instructions, such as those making up a computer program. As an example and not by way of limitation, to execute instructions, processor  702  may retrieve (or fetch) the instructions from an internal register, an internal cache, memory  704 , or storage  706 ; decode and execute them; and then write one or more results to an internal register, an internal cache, memory  704 , or storage  706 . In particular embodiments, processor  702  may include one or more internal caches for data, instructions, or addresses. Although this disclosure describes and illustrates a particular processor, this disclosure contemplates any suitable processor. 
     In particular embodiments, memory  704  includes main memory for storing instructions for processor  702  to execute or data for processor  702  to operate on. In certain embodiments, memory  704  may be memory  214  above. As an example and not by way of limitation, computer system  700  may load instructions from storage  706  or another source (such as, for example, another computer system  700 ) to memory  704 . Processor  702  may then load the instructions from memory  704  to an internal register or internal cache. To execute the instructions, processor  702  may retrieve the instructions from the internal register or internal cache and decode them. During or after execution of the instructions, processor  702  may write one or more results (which may be intermediate or final results) to the internal register or internal cache. Processor  702  may then write one or more of those results to memory  704 . In particular embodiments, processor  702  executes only instructions in one or more internal registers or internal caches or in memory  704  (as opposed to storage  706  or elsewhere) and operates only on data in one or more internal registers or internal caches or in memory  704  (as opposed to storage  706  or elsewhere). One or more memory buses (which may each include an address bus and a data bus) may couple processor  02  to memory  704 . Bus  712  may include one or more memory buses, as described below. In particular embodiments, one or more memory management units (MMUs) reside between processor  702  and memory  704  and facilitate accesses to memory  704  requested by processor  702 . Although this disclosure describes and illustrates particular memory, this disclosure contemplates any suitable memory. 
     In particular embodiments, storage  706  includes mass storage for data or instructions. In certain embodiments, storage  706  may be storage  230  above. 
     Storage  706  may include removable or non-removable (i.e., fixed) media, where appropriate. Storage  706  may be internal or external to computer system  700 , where appropriate. In particular embodiments, storage  706  is non-volatile, solid-state memory. Where appropriate, storage  706  may include one or more storages  706 . Although this disclosure describes and illustrates particular storage, this disclosure contemplates any suitable storage. 
     In particular embodiments, I/O interface  708  includes hardware, software, or both providing one or more interfaces for communication between computer system  700  and one or more I/O devices. Computer system  700  may include one or more of these I/O devices, where appropriate. One or more of these I/O devices may enable communication between a person and computer system  700 . As an example and not by way of limitation, an I/O device may include a keyboard, keypad, microphone, monitor, mouse, printer, scanner, speaker, still camera, stylus, tablet, touchscreen, trackball, video camera, another suitable I/O device or a combination of two or more of these. An I/O device may include one or more sensors. This disclosure contemplates any suitable I/O devices and any suitable I/O interfaces  708  for them. Where appropriate, I/O interface  708  may include one or more device or software drivers enabling processor  702  to drive one or more of these I/O devices. I/O interface  708  may include one or more I/O interfaces  708 , where appropriate. Although this disclosure describes and illustrates a particular I/O interface, this disclosure contemplates any suitable I/O interface. 
     In particular embodiments, communication interface  710  includes hardware, software, or both providing one or more interfaces for communication (such as, for example, packet-based communication) between computer system  700  and one or more other computer systems  700  or one or more networks. As an example and not by way of limitation, communication interface  710  may include a network interface controller (NIC) or network adapter for communicating with an Ethernet or other wire-based network or a wireless NIC (WNIC) or wireless adapter for communicating with a wireless network, such as a Wi-Fi network. This disclosure contemplates any suitable network and any suitable communication interface  710  for it. Although this disclosure describes and illustrates a particular communication interface, this disclosure contemplates any suitable communication interface. 
     In particular embodiments, bus  712  includes hardware, software, or both coupling components of computer system  700  to each other. Although this disclosure describes and illustrates a particular bus, this disclosure contemplates any suitable bus or interconnect. 
     Herein, reference to a computer-readable storage medium encompasses one or more non-transitory, tangible, computer-readable storage media possessing structure. As an example and not by way of limitation, a computer-readable storage medium may include a semiconductor-based or other integrated circuit (IC) (such, as for example, a field-programmable gate array (FPGA) or an application-specific IC (ASIC)), a hard disk, an HDD, a hybrid hard drive (HHD), an optical disc, an optical disc drive (ODD), a magneto-optical disc, a magneto-optical drive, a floppy disk, a floppy disk drive (FDD), magnetic tape, a holographic storage medium, a solid-state drive (SSD), a RAM-drive, a SECURE DIGITAL card, a SECURE DIGITAL drive, or another suitable computer-readable storage medium or a combination of two or more of these, where appropriate. A computer-readable non-transitory storage medium may be volatile, non-volatile, or a combination of volatile and non-volatile, where appropriate. 
     This disclosure contemplates one or more computer-readable storage media implementing any suitable storage. In particular embodiments, a computer-readable storage medium implements one or more portions of processor  702  (such as, for example, one or more internal registers or caches), one or more portions of memory  704 , one or more portions of storage  706 , or a combination of these, where appropriate. In particular embodiments, a computer-readable storage medium implements RAM or ROM. In particular embodiments, a computer-readable storage medium implements volatile or persistent memory. In particular embodiments, one or more computer-readable storage media embody software. Herein, reference to software may encompass one or more applications, bytecode, one or more computer programs, one or more executables, one or more instructions, logic, machine code, one or more scripts, or source code, and vice versa, where appropriate. In particular embodiments, software includes one or more application programming interfaces (APIs). This disclosure contemplates any suitable software written or otherwise expressed in any suitable programming language or combination of programming languages. In particular embodiments, software is expressed as source code or object code. 
     Herein, “or” is inclusive and not exclusive, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A or B” means “A, B, or both,” unless expressly indicated otherwise or indicated otherwise by context. Moreover, “and” is both joint and several, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A and B” means “A and B, jointly or severally,” unless expressly indicated otherwise or indicated otherwise by context. 
     This disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Similarly, where appropriate, the appended claims encompass all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Moreover, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. 
     Any of the steps, operations, or processes described herein may be performed or implemented with one or more hardware or software modules, alone or in combination with other devices. In one embodiment, a software module is implemented with a computer program product comprising a computer-readable medium containing computer program code, which can be executed by a computer processor for performing any or all of the steps, operations, or processes described. 
     Embodiments of the invention may also relate to an apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes, and/or it may comprise a general-purpose computing device selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a tangible computer readable storage medium or any type of media suitable for storing electronic instructions, and coupled to a computer system bus. Furthermore, any computing systems referred to in the specification may include a single processor or may be architectures employing multiple processor designs for increased computing capability. 
     While particular embodiments of inventory system  100  are illustrated, it should be appreciated that the teaching of the present disclosure may be applied to any type and number of inventory systems. For example, inventory system  100  may represent a merchandise return facility. In such embodiments, inventory items may represent merchandise returned by customers. Such merchandise may be stored in inventory holders  130  when received at the facility from individual customers. At appropriate times, large numbers of units may be removed from a particular inventory holder  130  and transferred at picking station  150  to an order holder  144 . For example, certain inventory items may be associated with a product recall, causing those inventory items to be returned in high volume. As another example, system  100  may represent a manufacturing facility, and inventory items may represent individual components of a manufacturing kit. Thus, individual items of the manufacturing kit may be stored in inventory holders  130 . Electronic order  145  for manufactured products may be assembled from the individual items at picking station  150 . Final products may be transported by mobile drive units  120  using order holders  144  and may be shipped to the appropriate destination. Thus, although a number of example embodiments are described in the present disclosure, inventory system  100  may, in general, represent any suitable facility or system for storing or processing inventory items, and inventory items may represent objects of any type suitable for storage, retrieval and/or processing in a particular inventory system  100 . 
     Although the present invention has been described with several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled in the art, and it is intended that the present invention encompass such changes, variations, alterations, transformations, and modifications as fall within the scope of the appended claims. Moreover, while the present disclosure has been described with respect to various embodiments, it is fully expected that the teachings of the present disclosure may be combined in a single embodiment as appropriate.