Abstract:
A system and method for reliably detecting singulated parcels traveling on a conveyor belt by comparing parcel characteristics before and after parcel agitation. First, parcel characteristics are evaluated. Then parcels are agitated to promote a change in characteristics, for example volume or dimensions, of the unsingulated parcels. Next, parcel characteristics are again evaluated and compared to the previously-evaluated characteristics. If there is no appreciable difference in characteristics, the parcel is deemed singulated.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application is a divisional application of co-pending U.S. patent application Ser. No. 10/215,502 (now U.S. Pat. No. ______), entitled SINGULATION DETECTION SYSTEM FOR OBJECTS USED IN CONJUNCTION WITH A CONVEYOR SYSTEM filed on Aug. 9, 2002 and incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates generally to singulation detection, and, more particularly to a system to reliably detect if parcels are singulated.  
         [0003]     In the past, parcels, such as packages traveling through the U.S. mail, were transported by a single conveyor belt to an automatic sorter. Each parcel could be labeled with a machine-readable bar code sticker, for example, but in the systems of the past, an attendant would have to orient the parcel so that the label could be detected and read by the sorter. To complicate the systems, often parcels were delivered to the sorter in bunches, making them difficult to handle and sometimes creating jams. Manual intervention would be required to perform a process known as singulation, or separation of the parcels from each other, to enable the automatic sorter to operate correctly so that the parcels could be properly distributed. Due to the non-uniform shape and size of parcels, this effort was time-consuming and cumbersome to the operating attendant.  
         [0004]     Automated package delivery systems such as mail processing systems now include automatic parcel singulation systems. These systems usually separate parcels, bundles, and other packages one from another to prepare them for automated distribution. But when the parcels are stacked or lying too close together, an automated system cannot always reliably singulate the parcels for proper sorting because a group of parcels can be seen as one parcel by the automatic system.  
         [0005]     Machines that address the problem of reliable singulation can include a singulator, a side-by-side remover, a flow controller, and a recirculating conveyer. In this type of equipment, parcels enter the singulator through an infeed and are driven to one side by skewed rollers. Successive belts increase in speed and create spaces between the packages. The skewed rollers align the packages to one side of the unit to form a straight line. A typical side-by-side remover transports downstream any packages of the width of the narrowest package while deviating other packages to be recirculated back onto the singulator. In some systems, the side-by-side remover is augmented by an optical recognition system that detects “piggy-back” items. Packages that are transported downstream enter a flow controller that meters the rate of packages that it discharges by inserting gaps between packages. Doubles and overflow packages are pulled off the flow controller belt and recirculated to the infeed of the singulator by the recirculating conveyor. Sometimes these automated systems use dimensioning equipment which automatically measures the external characteristics of parcels as they move along a conveyor.  
         [0006]     The current systems are deficient, however, when it comes to reliably identifying improperly singulated articles. What is needed is a system that decreases the likelihood that parcels are determined to be singulated when in fact they are not.  
       SUMMARY OF THE INVENTION  
       [0007]     The problems set forth above as well as further and other problems are solved by the present invention. The solutions and advantages of the present invention are achieved by the illustrative embodiment of the present invention described hereinbelow.  
         [0008]     The parcel singulation detection system of the present invention subjects at least one parcel group to an agitation device and then tests if the parcels have been separated from one another (singulated). At least one parcel group containing at least one parcel enters the system of the present invention and is identified. Its initial parcel group characteristics are evaluated, and it is subjected to agitation. After the parcel group is subjected to agitation, it is again identified and its current parcel group characteristics are evaluated. A controller compares initial and current characteristics to determine if the at least one parcel has been singulated from the identified at least one parcel group.  
         [0009]     The parcel singulation detection system of the present invention includes a transport subsystem, a parcel order subsystem, an evaluation subsystem, an agitation subsystem, and a controller. The transport subsystem is capable of receiving and moving the parcel group(s). The evaluation subsystem is capable of evaluating initial characteristics and current characteristics of the parcel group(s). The agitation subsystem is capable of subjecting the parcel group(s) to agitation. The agitation subsystem is capable of modifying the initial characteristics of the parcel group(s). The parcel order subsystem is capable of associating a parcel order number with the parcel group(s) and any parcels that are separated from the parcel group(s) as a result of agitation. The controller is capable of receiving the initial characteristics and the current characteristics from the evaluation subsystem for the parcel group(s) or parcel identified by the parcel order subsystem with a parcel order number. Further, the controller is capable of computing an absolute value of the difference between the current characteristics and the initial characteristics, and is capable of computing a comparison value as a function of comparing the absolute value to a predetermined threshold. The controller is capable of setting a “singulation status” as a function of the comparison value.  
         [0010]     The transport subsystem includes, for example, but is not limited to, a transport device having an intake area and an output area. The transport device moves at least one parcel group from the intake area to the output area. The transport device, for example, can be a conveyor belt, motorized rollers, etc., having a pre-selected length dimension and a pre-selected width dimension.  
         [0011]     The evaluation subsystem can include, for example, a first evaluation device that evaluates the initial characteristics of the parcel group(s), possibly at the intake area, and at least one subsequent evaluation device that evaluates the current characteristics of the parcel group(s) temporally after the first evaluation device evaluates the initial characteristics, possibly between the intake area and the output area. The first evaluation device and the subsequent evaluation device(s) may each be, for example, a conventional light curtain, a laser based scanner, or any other type of automated parcel characteristics evaluation equipment. Characteristics can include dimensions of the parcel group as well as its location and position relative to surrounding parcels.  
         [0012]     The agitation subsystem can include at least one agitation device positioned between the intake area and the output area. The agitation device(s) can be, among other things, a conventional fixed paddle or a conventional herringbone roller module.  
         [0013]     The parcel order subsystem can include, among other things, a plurality of conventional photo cells capable of associating the parcel order number with the parcel group(s). Each of the photo cells is capable of associating a “lost” or “found” indicator with the parcel group(s) in the conventional way as follows. The photo cells determine the expected time when the parcel group(s) should pass a next subsequent photo cell. If a parcel group does not arrive at the next subsequent photo cell at expected time, either because there are multiple parcels arriving, no parcels arriving, or parcels arriving early or late, the parcel order subsystem processes the situation accordingly by associating “lost” or “found” indicators with the parcel, and creating a new parcel data block and assigning new parcel order numbers when appropriate.  
         [0014]     The controller includes, but is not limited to, a data collection system and a comparator system. The data collection system is capable of receiving collected data such as initial characteristics, current characteristics, parcel order number, and parcel timing information, and perhaps stores these data for later reference in, for example, a parcel data block. The comparator system can identify a particular parcel by parcel order number and can compute an absolute value of a difference between the initial characteristics and the current characteristics of the particular parcel to determine if the parcel is singulated from a parcel group. If the absolute value of the difference is less than a threshold value, the singulation status associated with the parcel is set to singulated.  
         [0015]     In operation, when the parcel group enters the system, the transport subsystem moves the parcel group past the parcel order subsystem. The parcel order subsystem tracks the parcel group through the system so that the evaluation subsystem can associate any characteristics it evaluates with the proper parcel group. The agitation subsystem is capable of separating the parcels in the parcel group from each other, thus requiring the parcel order subsystem to manage the ordering of parcels after agitation so that the evaluation subsystem can properly associate any subsequent characteristics it evaluates with the proper parcel.  
         [0016]     After the parcel group passes the parcel order subsystem, the transport subsystem moves the parcel past the evaluation subsystem. The evaluation subsystem first computes initial characteristics and then, later, computes current characteristics.  
         [0017]     Next the transport subsystem moves the parcel group(s) past the agitation subsystem. The agitation subsystem subjects the parcel group(s) to agitation to possibly change the characteristics of the parcel group(s). During all these steps, the controller can collect data including initial characteristics, current characteristics, and parcel tracking information. The controller can compute a singulation status for each parcel group as a function of the data collected by the controller. The controller associates the singulation status with each parcel group, and transmits the singulation status to any subsequent parcel processing system, perhaps a subsequent system such as a shoe sorter system (not part of this invention).  
         [0018]     The method of the present invention includes the steps of identifying at least one parcel group and evaluating initial characteristics of the parcel group. The method further includes the steps subjecting at parcel group to agitation and testing for parcel order change. If the parcel order has changed, the method includes the step of associating a new parcel order and lost/found indicators with any lost/found parcels. The method further includes the steps of evaluating current characteristics of the parcel group and any found parcels and testing the absolute value of a threshold value against a difference between the current characteristics and the initial characteristics. If the difference is less than or equal to the threshold, the method includes the step of setting a singulation status to singulated. If the difference is greater than the threshold, the method includes the step of setting the singulation status to not singulated. Optionally, if the system includes more than one subsequent evaluation device (such as a dimensioner), the method can include the step of repeating the identifying, evaluating, agitating, testing, and status setting for each evaluation device in the system.  
         [0019]     The method of the illustrative embodiment of the present invention can optionally include the steps of creating a parcel data block, storing the initial and current characteristics in the parcel data block, and storing the singulation status in the parcel data block. The step of identifying can optionally further include the steps of storing a parcel order number in the parcel data block and tracking the parcel group and the lost/found parcels by the parcel order number.  
         [0020]     The method of the illustrative embodiment of the present invention can optionally include the step of configuring a transport device, such as a conveyor belt, which has a length dimension and a direction of travel and the capability to move the parcel group along the direction of travel. The method can further optionally include the step of configuring a first evaluation device, at least one subsequent evaluation device, a first parcel order device, at least one subsequent parcel order device, and at least one agitation device, all situated along the length dimension of the transport device.  
         [0021]     For a better understanding of the present invention, together with other and further objects thereof, reference is made to the accompanying drawings and detailed description. The scope of the present invention is pointed out in the appended claims. 
     
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING  
       [0022]      FIG. 1  is a schematic representation of the parcel singulation detection system of the illustrative embodiment of the present invention;  
         [0023]      FIG. 2  is a schematic block diagram of the collection system and parcel data block of the illustrative embodiment of the present invention;  
         [0024]      FIGS. 3A, 3B , and  3 C are parcels groups shown in various orientations as examples of various configurations of parcels that could be agitated and tested for singulation status by the present invention;  
         [0025]      FIG. 4  is a flow chart of the method of the illustrative embodiment of the present invention;  
         [0026]      FIG. 5  is a schematic representation of the parcel singulation system of an alternate embodiment of the present invention in which there are multiple evaluation devices;  
         [0027]      FIG. 5A  is a schematic representation of the parcel singulation system of another alternative embodiment of the present invention in which there are multiple evaluation devices and a herringbone roller module; and  
         [0028]      FIG. 6  is a flow chart of the method of the alternate embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]     The present invention is now described more fully hereinafter with reference to the accompanying drawings, in which the illustrative embodiment of the present invention and an example of an alternate embodiment of the present invention are shown.  
         [0030]     The system of the illustrative embodiment of the present invention is generally indicated by numerical designation  10  as shown in  FIG. 1 . System  10  generally includes controller  101 , evaluation or dimensioning subsystem  107 , parcel order subsystem  109 , transport subsystem shown here as conventional conveyor belt  121 , and agitation subsystem shown here as conventional agitators  123 . Dimensioning subsystem  107  includes, but is not limited to, conventional dimensioners  119 , and parcel order subsystem includes, but is not limited to, conventional photo cells  115 . The dimensioners  119 , agitators  123 , and photo cells  115  are operably positioned along length dimension  127  of conveyor belt  121 .  
         [0031]     Parcel groups  124 / 125  enter system  10  of the present invention at intake area  113  having conveyor belt width dimension  129 . As parcel groups  124 / 125  enter system  10 , conveyor belt  121  moves them in a direction of travel past photo cells  115 , dimensioners  119 , and agitators  123 . A first photo cell  115  establishes a parcel group order number of the passing parcel groups  124 / 125  and establishes an expected time at which the next photo cell  115  should expect to see those particular parcel groups. Initial characteristics (referred to herein as “initial measurements”) of passing parcel groups  124 / 125  are evaluated by a first evaluation device or dimensioner  119 .  
         [0032]     Referring now to  FIGS. 1 and 2 , time-lapse positions of passing parcel groups  124 / 125  are shown at two different times (in  FIG. 1 ), a first time before agitation and a second time after agitation. As shown in  FIG. 1 , after parcel group  124 , which includes parcels B and C, is agitated, it is no longer an intact parcel group, but instead parcels B and C are singulated. The first photo cell  115  has set an expected time  213  (see  FIG. 2 ) in parcel data block  103  for the B/C parcel group to pass the next photo cell  115 . Since the parcel group has now been separated, parcels B and C are seen separately. It is possible that neither will pass photo cell  115  at the expected time  213 . In this case, photo cell  115  could, in new parcel data blocks  103  created for parcels B and C, associate “found” indicators  215  and new parcel order numbers  217  with parcels B and C. Photo cell  115  could associate a “lost” indicator  215  with parcel group  124  in the parcel data block  103  for parcel group  124 . If parcels B and C are “found” in this way, their initial measurements  209  are computed by any dimensioner  119  that first evaluates their characteristics as autonomous parcels and stores their physical characteristic data (referred to in  FIG. 2  as “initial measurements”) in the parcel data blocks  103  created for them when they were “found”.  
         [0033]     Continuing to refer to  FIGS. 1 and 2 , the process of agitation should not substantially change the characteristics of parcel A. When its current characteristics or measurements  211  are taken for parcel A by dimensioner  119 , they will not be substantially different from initial measurements  209  taken for parcel A, depending upon the tolerance of the equipment and the choice of threshold  202 . Thus the controller  101 , when comparing initial measurements  209  to current measurements  211  for parcel A, can associate a singulation status  207  of singulated with parcel A because the absolute value of the difference between the two measurements is below a pre-determined threshold  202 . After agitation, the controller  101  will not, depending again upon the equipment, reach the same result with parcels B and C, since these parcels have no current measurements  211  stored in their parcel data blocks  103  with which to compare their initial measurements  209  taken after agitation. Thus, such a comparison will fail. A singulation status  207  of not singulated will probably be associated with parcels B and C. Note that the choice of equipment and threshold  202  can change the orientation of the singulation status  207  for the same parcel group.  
         [0034]     As shown in  FIG. 1 , parcels, singulated or not, pass by shared photo cell  116  in the direction of output area  117 . Parcel data information embodied in parcel data block  103  is distributed through a system such as, for example, network  111  to a subsequent system  105 , which is not part of this invention, but which can share, by design, photo cell  116  and can receive parcel data block  103  through network  111 .  
         [0035]     Referring now to  FIG. 2 , controller  101  includes comparator  201 , data collection system  203 , and photo cell data interface  205 . The controller  101  receives conventional parcel group ordering and timing information from photo cells  115  and  116  through photo cell data interface  205  and parcel group measurements through data collection system  203  from dimensioners  119 . Comparator  201  can compare the evaluated initial and current characteristics (initial and current measurements ( 209 / 211 )), and can determine, through initial and current characteristics comparisons (initial and current measurement comparisons) if parcels are singulated.  
         [0036]     The illustrative embodiment dimensioner  119  is, for example, a conventional light curtain, such as, preferably, a Cargoscan CS5000/CS5000HS Measuring frame, or a conventional laser based scanner such as Mettler Toledo® CS5120 and CS5200, Accusort DM3000, or Adaptive Optics Associates® MSDS, all of which can be used to evaluate characteristics of parcel groups. Of particular interest in certain applications is the evaluation of characteristics such as Cargoscan&#39;s “R-value”. This value indicates the deviation in shape between the parcel being evaluated and an ideal cubic shape. R-value is only one example of a characteristic that would be of value in singulation determination according to the present invention.  
         [0037]     The conventional conveyor belt  121  of the illustrative embodiment of the present invention has a width dimension  129  and a length dimension  127  and a direction of travel from intake area  113  to output area  117 , as indicated by large arrows in  FIG. 1 . Where a light curtain is used, dimensioners  119  are preferably positioned in predetermined gaps along the conveyor belt in order that the vertical portion of the light curtain, which measures width, is operational.  
         [0038]     Agitators  123  of the illustrative embodiment can be conventional passive or active agitators, preferably fixed paddles such as the Pegasus Industrial Specialties Inc. ST  1 / 2  or herringbone roller modules such as those manufactured by Ermanco.  
         [0039]     The system of the illustrative embodiment of the present invention employs two conventional dimensioners  119  in tandem, surrounding two conventional agitators  123 , on conventional conveyor  121  that is at least 5-10 feet long. However, this combination of components and dimensioners is presented for illustrative purposes only and may vary in accordance with the usage of the present invention.  
         [0040]     Non-singulated parcel groups are illustrated in  FIGS. 3A, 3B , and  3 C.  FIG. 3A  shows two parcels  301  and  303  side-by-side. Because there is no gap between the parcels, the dimensioner could consider them a single parcel. However, after proceeding through the agitators, parcels  301  and  303  could likely be separated.  FIG. 3B  illustrates a more complicated parcel group including three parcels,  301 ,  303 , and  305 . Although a single agitation might separate these three parcels from one another, more than one agitation might be required.  FIG. 3C  shows parcel  301  on top of parcel  303 . Multiple agitations could be required in this case as well.  
         [0041]     Referring now to  FIG. 4 , the method of the illustrative embodiment of the present invention includes the steps of identifying a parcel group by establishing a parcel order number and an expected time of arrival at the next parcel ordering station (method step  401 ), evaluating initial characteristics, i.e. taking initial measurements of the identified parcel group (method step  403 ), and subjecting the parcel to agitation (method step  405 ). If the order of the parcels has changed, i.e. if the identified parcel group does not arrive at the next parcel ordering station at the expected time (decision step  407 ), a new parcel ordering is associated with the parcel group or parcel that does arrive at the next parcel ordering station and lost/found indicators are associated appropriately with parcels now known to the system (method step  409 ). In this case, the parcel is considered not singulated, and the process moves on to set the status accordingly (method step  415 ). If the parcel order has not changed, the method next includes the step of evaluating current characteristics, i.e. taking current measurements of the parcel group (method step  411 ). If the absolute difference between the initial measurements and the current measurements is greater than a threshold (decision step  413 ), then the method includes the step of setting the singulation status to not singulated (method step  415 ). Otherwise, the method includes the step of setting the singulation status to singulated (method step  417 ).  
         [0042]      FIG. 5  illustrates an alternate embodiment (system  20 ) in which are shown an additional dimensioner  119  and additional agitators  123  along conveyor belt  121 . The system  20  generally includes at least three conventional dimensioners  119 , and at least two conventional agitator pairs  123 . Though three evaluation devices and two agitation devices are disclosed, any number of each can be used to configure a singulation detection device that achieves the primary objective of the system to jostle and separate objects through the use of agitation and detect separation through characteristic evaluation and parcel ordering. Controller  501  is enhanced to receive data from additional dimensioners. The remaining system components have the same function as the illustrative embodiment depicted in  FIG. 1 .  
         [0043]      FIG. 5A  illustrates the embodiment of  FIG. 5  with the addition of herringbone roller module  123 A which can jostle and separate objects on conveyor belt  121 .  
         [0044]      FIG. 6  is a flowchart of the method of use of the alternate embodiment of the present invention. The method includes the steps of identifying a parcel group and taking initial measurements (method step  601 ). Next the method includes the step of subjecting the parcel group to agitation (method step  603 ). If the parcel ordering has changed (decision step  605 ), the method includes the step of associating a new parcel ordering and lost/found indicators with any lost/found parcels (method step  607 ). In this case, the parcel is considered not singulated and the status is set accordingly (method step  613 ). If the parcel ordering has not changed, the method next includes the step of taking current measurements of parcel groups in the system (method step  609 ). If the absolute value of the difference between the initial measurements and the current measurements is less than or equal to a predetermined threshold (decision step  611 ), the method includes the step of setting a singulation status for the parcel group to singulated (method step  615 ). Otherwise, the method includes the step of setting the singulation status for the parcel group to not singulated (method step  613 ). If there are more evaluation devices in the system (decision step  617 ), method and decision steps  603 - 617  are repeated until there are no more evaluation devices in the system.  
         [0045]     The method of the illustrative embodiment of the present invention may be, in whole or in part, automated through use of a computer program, which may be stored on computer-readable media. Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, a hard disk, magnetic tape, or any other magnetic medium, a CDROM, any other optical medium, punched cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave, or any other medium from which a computer can read.  
         [0046]     Although the invention has been described with respect to various embodiments, it should be realized this invention is also capable of a wide variety of further and other embodiments within the spirit and scope of the appended claims.