Abstract:
A system provides a more robust measurement of scanned items at a self-checkout station. The system comprises an item verifier for verifying placement of an item on a scale of a self-checkout station and a measurement adjuster operatively coupled to the item verifier for adjusting the item verifier operation in response to an error signal from the item verifier. In one embodiment, the measurement adjuster increases the number of samples for determining the weight of an item. By increasing the number of samples collected before determining item weight, the probability that temporary vibrations will not disturb weight measurement is increased. An exemplary method to implement the system includes verifying placement of an item on a scale and adjusting the weighing of the item in response to a failure to sense a weight that corresponds to the item placed on the scale. The adjustment may include increasing the number of samples collected or the time between samples.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to methods and systems for facilitating transactions at a self-checkout terminal and, more particularly, to methods and systems for facilitating transaction at self-checkout terminals with scales. 
     BACKGROUND OF THE INVENTION 
     Self-checkout terminals at grocery stores and other retail stores are well known. The terminals permit a consumer to present items for purchase to sensors at the terminal so the terminal can identify the items and a corresponding price. When the consumer indicates all items for purchase have been presented to the terminal, a sub-total is accumulated, any taxes and discounts are computed, and a total amount due is displayed for the consumer. The terminal then allows the consumer to select a payment method. The terminal presents menu selections to the consumer so funds are transferred to the retailer&#39;s account. Upon confirmation of payment, the items are released to the consumer. 
     A self-checkout terminal typically includes a display, a scanner for reading unit price codes (UPC), and a checkout area for holding items once they have been scanned. The checkout area may include a motor driven belt to carry items for which a purchase has been verified to a collection area. The terminal also includes a processor, memory, programmed instructions, and data peripherals to control the operations of the terminal. The programmed instructions may contain modules for querying for item prices, computing totals and performing other functions related to the purchase of items through a self-checkout terminal. Some checkout terminals may also include a security application program that operates to reduce the likelihood that the consumer leaves without scanning all of the items or exchanges scanned items with more expensive items that have not been scanned. In many self-checkout terminals, the surface area of the checkout area or belt has a scale underneath it to help track items during checkout. By monitoring the weight of items placed on the checkout area, the security application is able to determine some actions of the consumer for purposes of detecting fraud or operator error by a consumer. For example, the change in weight detected by the scales of the checkout area may be used to determine the weight of an item just placed on the checkout area. This item weight may then be compared to the weight of the item last scanned that is stored in a database or other memory. If the weights are different, the security application program notifies the consumer and prompts the consumer to remove the item and scan the item again to rectify the discrepancy. Thus, the application program is capable of tracking the scanning of items and their placement on the checkout area through its monitoring of the scales associated with the checkout area. 
     While this type of item monitoring is useful for security tracking purposes it does have some drawbacks. For one, activities in the vicinity of the scales may affect the accuracy of the weighing operations. For example, vibrations caused by carts or other objects impacting a self-checkout station may oscillate one or more items on the scale and displace the items with respect to the weighing transducers. Other activities that may affect weighing operations include pressure from a consumer&#39;s hand on an item, the serial placement of items on the scale that were purchased at the same time, or air pressure from air ducts located near the checkout station. For example, a consumer may scan a group of three oranges having a single unit price (3 oranges/$1) and then place them one at time on the scales. 
     Activities like the ones described cause measurements of the weight of items placed on the scales to fluctuate. These fluctuations result in measured weights that do not correspond to the weight stored in association with an item&#39;s bar code or other identifier. In previously known self-checkout stations, the scale control software requires N weight readings within a tolerance T of a weight value stored in association with an item identifier such as its bar code. Fluctuations in weight readings may prevent the accumulation of N readings within a weight sampling period and cause the terminal control software to determine that an item placed on the scales does not correspond to a scanned item. The checkout process is then delayed until the weight of the scanned item is verified. Verification may require rescanning by the consumer after the last item is removed from the items scanned list or it may require the intervention of a cashier or other self-checkout station attendant. Both verification procedures are time-consuming and adversely impact the efficiency of the self-checkout process. 
     What is needed is a system and method of weighing scanned items that compensates for weighing irregularities caused by activities in the vicinity of the self-checkout station. 
     What is needed is a system and method for measuring the weight of scanned items at a self-checkout station that reduces the necessity of rescanning items or attendant intervention to verify the weight of an item. 
     SUMMARY OF THE INVENTION 
     The above-noted limitations of previously known systems and methods for tracking items in the checkout area of a self-checkout terminal have been overcome by a system and method that operate in accordance with the principles of the present invention. The system of the present invention comprises an item verifier for verifying placement of an item on a scale of a self-checkout station and a measurement adjuster operatively coupled to the item verifier for adjusting the item verifier operation in response to an erroneous reading signal from the item verifier. 
     In one embodiment of the present invention, the measurement adjuster increases the number of samples required by the item verifier for determining the weight of an item. By increasing the number of samples collected before determining the weight of the item, the probability that temporary vibrations will not disturb an accurate weight measurement is increased. For example, if N weight measurements with tolerance T are required to verify the placement of an item on scale then an increase in the number of samples collected provides more time for vibrations to dampen or a consumer&#39;s hand to be removed from the item. In another embodiment of the present invention, the period between samples is increased so an accurate weight measurement may be obtained without interference from vibrations, a consumer&#39;s hand, or the like. 
     The system of the present invention may be implemented with a self-checkout terminal that includes a display, a bar code scanner, and a checkout scale, all of which are coupled to the processor for the terminal. The checkout scale may include a processor operated by programmed instructions with memory for collecting and analyzing weight data or it may provide the weight data to data peripheral interfaces for the terminal processor. The program memory of the terminal processor may include one or more program modules for determining whether the checkout scale processor requires adjustment. The program memory may also include a security application that uses the item weight data to track items in the checkout area. The display may be used to communicate with the consumer regarding movement of items in the checkout area. 
     The method of the present invention includes verifying placement of an item on a scale of a self-checkout station and adjusting the weighing of the item in response to a failure to sense a weight corresponding to the identification of the item placed on the scale. The adjustment may be an increase in the number of weight samples collected for verification so the likelihood of collecting a prerequisite number of samples within the toleration range for verification is increased. Alternatively, the adjustment may be an increase in the time between weight measurement samples. These adjustments increase the time required for measuring the weight of an item placed on a scale, however, they reduce the likelihood that the weight measured by the scale is erroneous because of temporary activities in the vicinity of the checkout station. Erroneous weight readings necessitate a consumer rescanning an item or a self-checkout attendant intervening in the checkout procedure. Thus, the method of the present invention reduces the occurrence of problems with self-checkout that are associated with erroneous weight measurements caused by temporary perturbations in the sensing of the weight on the scale of the self-checkout station. 
     It is an object of the present invention to provide a more robust scheme for measuring the weight of items placed on the scale of a self checkout station. 
     It is an object of the present invention to provide an adjustment to the process of determining the weight of an item placed on the scale of a self-checkout station so fluctuations are less likely to prevent the verification of a scanned item. 
     It is an object of the present invention to increase the time for determining the weight of a scanned item placed on the scale of a self-checkout station so that an accurate measurement of the item&#39;s weight is not disturbed by temporary vibrations or additional weight. 
     These and other advantages and features of the present invention may be discerned from reviewing the accompanying drawings and the detailed description of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention may take form in various system and method components and arrangement of system and method components. The drawings are only for purposes of illustrating an exemplary embodiment and are not to be construed as limiting the invention. 
     FIG. 1 depicts a block diagram of a self-checkout station in which the present invention may be used; 
     FIG. 2 is a block diagram of an exemplary embodiment of the components for adjusting the weight measurement of items scanned by the station shown in FIG. 1; and 
     FIG. 3 is a flowchart of an exemplary method for adjusting the verification of items scanned by the station shown in FIG.  1 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A self-checkout station used with the system and method of the present invention is shown in FIG.  1 . Checkout station  10  may include a feeder unit  14  and a checkstand  18 . Feeder unit  14  includes a feeder belt  20  and housing  22  for the motor and control circuitry that operates feeder belt  20 . Feeder unit  14  is movably coupled to checkstand  18  so the feeder belt may be aligned with scanner/scale unit  26 . Checkstand  18  includes scanner/scale unit  26 , consumer terminal  34 , a payment terminal  38  for entry of payment data, and receipt printer  44 . Scanner/scale unit  26  uses a laser shining on a glass or other transparent platen to input data from bar codes applied to products or packages. Unit  26  may also include a scale for measuring the weight of items that are sold on a price/unit of weight basis. Consumer terminal  34  displays item data as it is entered through scanner/scale unit  26 . Payment terminal  38  may be any known POS terminal that incorporates a keypad and card reader to support credit card, debit card, and other payment methods. Receipt printer  44  provides a consumer with a receipt itemizing the items purchased and the method of payment. 
     Separating receipt printer  44  and scanner/scale unit  26  is a bagwell  46 , which has a floor that is adjoined to three upright walls. The floor of bagwell  46  may rest on scale  48 . Consumers place scanned items in bags hanging from rails  50  in bagwell  46  so the items rest on the floor of bagwell  46  and scale  48 . Security scale  48  uses item weight data derived from scanner/scale  26  or a database using a scanned unit product code (UPC) to verify that only the items scanned are placed on the security scale. Security application programs operating within terminal  34  monitor security scale  48  to determine whether items not scanned have been added to the security scale area. An anomalous condition that requires investigation may be signaled by lighting a warning or alert light color within the tri-color indicator  54  mounted at the terminal end of indicator pole  52  of checkstand  18 . Indicator pole  52  may also have mounted thereon a security camera  56  for providing a video signal to a security officer surveillance area or to some storage media. A database, disk drive, or other computer peripheral required for station operation may be housed within peripheral tray  60  located within checkstand  18 . Checkstand  18  also includes currency acceptor  40  for receiving units of paper currency and coins from a consumer as payment for a transaction while cash dispenser  42  returns change to a consumer or funds requested from a debit account or the like. 
     As shown in FIG. 1, a consumer may place items on feeder belt  20  and belt  20  is driven to bring items to the end of belt  20  where a shut-off mechanism stops belt  20 . The consumer may commence a transaction by removing items from belt  20  and moving them, one at a time, over scanner/scale  26  for item product data retrieval and/or weighing. The scanned items may then be placed in bags on security scale  48 . Once all of the items are scanned, a consumer may provide payment through payment terminal  38  or currency acceptor  40 , receive change from dispenser  42 , and a receipt from printer  44 . The consumer may then remove the bags from security scale  48  and leave station  10  to complete a transaction. 
     In one embodiment of the present invention, an item weighing adjustment system may reside in the computer that controls terminal operation for the checkout stand or in the computer that controls operation of scale  48 . The item weighing adjustment system includes the components shown in the block diagram of FIG.  2 . System  68  includes an item verifier  70  and a measurement adjuster  74 . Item verifier  70  receives weight data sensed by scale  48  as well as weight data stored in association with an identifier for the last item scanned. Verifier  70  compares the sensed weight data to the stored weight data to determine whether the sensed data is within a tolerance range about the stored weight data for the scanned item. Verifier  70  generates a signal indicative of whether the sensed weight data is in the tolerance range about the stored weight data and transmits the weight reading signal to measurement adjuster  74 . In response to the signal, measurement adjuster  74  determines whether to adjust the verification process of verifier  70 . After the verifier  70  completes the verification process, it generates a verification signal and the state of that signal indicates to the program controlling terminal  34  whether the last scanned item was placed on scale  48  or not. The security program of terminal  34  may then determine the appropriate response for reducing the likelihood of fraudulent activity in the ongoing transaction. 
     An exemplary process that may be implemented by verifier  70  and adjuster  74  in accordance with the principles of the present invention is shown in FIG.  3 . The process retrieves the stored weight for the last scanned item (block  100 ) and also receives the latest weight reading from scale  48  (block  104 ). The sensed weight reading is compared to the retrieved weight data to determine whether it is within a tolerance range about the retrieved weight data (block  108 ). This may be performed by a number of methods. One method is to read the total weight of the scale and subtract the last verified reading to determine a differential weight that corresponds to the weight of the last scanned item. A tolerance weight T may then be added to and subtracted from the retrieved weight for the item. This tolerance weight range may then be compared to the differential weight. Alternatively, the retrieved weight may be added to the last verified reading and the tolerance weight T may then be added to and subtracted from this value to determine the tolerance range for comparison with the weight readings. 
     If a weight reading is within the computed tolerance range, the sample counter for weight readings is reduced (block  110 ) and verifier  70  may generate an in-range weight reading signal for adjuster  74  that is indicative of a weight reading within the tolerance range. The sample counter is initialized at the beginning of an item verification to a number of samples that have been determined adequate for establishing a stable reading from scale  48 . The number of samples N 1  is set at a number that provides a reliably accurate weight reading within a minimum time for item verification when scale  48  is not subject to activities that affect the accuracy of weight measurement. The number of samples for this minimum time may determined by empirical data before placing system  68  into operation or it may be determined from an analysis of historical weight data by verifier  70 , adjuster  74 , or terminal  34 . The samples may be read at a periodic rate so that the N 1  samples define a weight sampling period for an item verification performed by verifier  70 . Alternatively, the samples may be acquired at a rate that is not periodic. While the number of samples N 1  may be used to initialize the sample counter for an item verification and then decremented, the number of samples may alternatively be used as a threshold to compare to a count accumulated in the sample counter as weight readings are obtained for item verification. 
     A determination is made as to whether all of the samples required for verifying that the weight of the item placed on the scale is within the tolerance range have been received (block  114 ). If not, the process continues until the reading stabilizes and the reading is verified as being within the tolerance range for the last scanned item. If a sensed weight is not within the tolerance range, verifier  70  generates an erroneous reading signal that is sent to adjuster  74 . Adjuster  74  may then determine what, if any, adjustment is made to the verification process (block  118 ). In response to the error signal, adjuster  74  may count the number of erroneous readings and only adjust the verification process when the number of erroneous signals exceeds a threshold. Alternatively, adjuster  74  may adjust the verification process upon receipt of a single error signal. 
     Adjustment of the verification process may be made in a number of ways. For one, adjuster  74  may provide a new value for the sample counter that increases the number of samples required for item verification. Alternatively, adjuster  74  may alter the rate at which verifier  70  receives sensed weight data from scale  48 . Both of these adjustments increase the time for measuring the weight increase caused by placement of the last scanned item on scale  48 . This increase in weight sampling time improves the chances of obtaining an accurate measurement that is not erroneously altered by vibrations, a lingering hand on the item, or serial placement of items in a single transaction unit. However, the adjustment does not adversely impact the ability of verifier  70  to detect the substitution of items on scale  48  that do not conform to the tolerance range about the weight stored for a last scanned item. Once the number of samples for determining the weight of a scanned item have been obtained, verifier  70  generates a signal for terminal  34  that indicates whether the weight of the item placed on the scale corresponds with the weight data stored for the last scanned item ( 120 ). 
     The system and method of the present invention may be implemented by adding functionality to an existing self-checkout terminal. That is, hardware and software may be added to existing checkout station processors, such as the processor terminal  34 , scale  48 , or a combination thereof. The system and method of the present invention provide a security application of terminal  34  with more robust data as the item verification analysis based on item weight becomes more resilient against false or erroneous readings arising from temporary activities in the vicinity of station  10 . 
     While the present invention has been illustrated by the description of exemplary processes and system components, and while the various processes and components have been described in considerable detail, it is not the intention of the applicant to restrict or in any limit the scope of the appended claims to such detail. Additional advantages and modifications will also readily appear to those skilled in the art. The invention in its broadest aspects is therefore not limited to the specific details, implementations, or illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant&#39;s general inventive concept.