Statistical sampling security methodology for self-scanning checkout system

• US 5,877,485 A
• Filed: 01/24/1997
• Issued: 03/02/1999
• Est. Priority Date: 01/25/1996
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Swartz, Jerome
• Primary Examiner(s): Gross, Anita Pellman
• Assistant Examiner(s): Dunn, Drew A.
• Application Number:
  US08/787,728
• Time in Patent Office: 767 Days
• Field of Search: 235/383, 235/385, 235/462, 186/61, 186/52, 705/16, 705/17, 705/23
• US Class Current: 235/383
• CPC Class Codes: G06Q 20/208 Input by product or record sensing, e.g. weighing or scanner processing
• CPC Class Codes: G07G 1/0054 with control of supplementary check-parameters, e.g. weight or number of articles
• CPC Class Codes: G07G 3/003 Anti-theft control theft alarms G08B13/00

Abstract

Disclosed is the implementation of a statistical basis for use in a self-scanning checkout system for determining how many items to check in a shopper'"'"'s shopping cart for incorrect or missing scans as well as which particular or types of items to check to determine if they were properly scanned by a shopper who may use a portable scanner or scanning terminal to scan bar codes on selected items. In the present invention, every or nearly every shopper will be checked by a cashier or security guard, but only a limited and select number of items will be checked for each shopper. The present methodology determines how many items to check for a given shopper as well as which particular items to check for that shopper. The following factors may be considered, alone or in varying combinations, in determining the number of items to check for a particular shopping transaction: shopper frequency (the number of times the shopper has visited that store); queue length (the length of the checkout line at that time); prior history (check more items if the shopper has had errors in the past, check less items if the shopper has had no errors in the past); store location (check more items in stores located in areas with a high risk of pilferage); time of day, day of week, date of year (determine if pilferage more likely at certain times of day or year); number of times items are returned to shelf during shopping; and dwell time between scans.

Claims

1. In a self-service shopping checkout system wherein a shopper is provided with a self-scanning terminal for the scanning of the bar code of an item selected for purchase prior to depositing the item into a shopping cart, and wherein a list of items self-scanned by the shopper is compiled and made available to a cashier for surveillance and payment purposes, the improvement comprising a method for performing a security check to determine if the shopper has failed to scan an item prior to depositing the item into the shopping cart, said method comprising the steps of:

a) determining, as a function of a plurality of input criteria, the number of items n to be scanned by the cashier;

b) selecting from the shopper'"'"'s cart of items presented for purchase n items to be scanned by the cashier;

c) scanning a bar code located on each of said n items selected for scanning;

d) allowing the shopping transaction if each item selected for scanning is present on the list of self-scanned items compiled by the shopper; and

e) disallowing the shopping transaction if any item selected for scanning is not present on the list of self-scanned items compiled by the shopper.

2. The method of claim 1 wherein the number of items n to be scanned by the cashier is determined by obtaining said number n from a computer memory.

3. The method of claim 2 further comprising the step of, when the shopping transaction has been allowed, decreasing the number of items n to be scanned and re-storing said decreased number n in said computer memory whereby the shopper will have less items scanned upon the next shopping transaction.

4. The method of claim 2 further comprising the step of, when the shopping transaction has been disallowed, increasing the number of items n to be scanned and re-storing said increased number n in said computer memory whereby the shopper will have more items scanned upon the next shopping transaction.

5. The method of claim 1 wherein the input criteria for determining the number of items n to be scanned comprises predetermined input criteria.

6. The method of claim 5 wherein the predetermined input criteria for determining the number of items n to be scanned comprises the frequency at which the shopper has previously utilized the self-service shopping checkout system.

7. The method of claim 5 wherein the predetermined input criteria for determining the number of items n to be scanned comprises the number of shoppers utilizing the self-service shopping checkout system.

8. The method of claim 5 wherein the predetermined input criteria for determining the number of items n to be scanned comprises the number of shoppers waiting to be checked out.

9. The method of claim 5 wherein the predetermined input criteria for determining the number of items n to be scanned comprises prior checkout history of the shopper utilizing the system at that time.

10. The method of claim 5 wherein the predetermined input criteria for determining the number of items n to be scanned comprises a risk factor associated with the geographic area in which the store is located.

11. The method of claim 5 wherein the predetermined input criteria for determining the number of items n to be scanned comprises a risk factor associated with prior theft history of the store.

12. The method of claim 5 wherein the predetermined input criteria for determining the number of items n to be scanned comprises the time of day.

13. The method of claim 5 wherein the predetermined input criteria for determining the number of items n to be scanned comprises the day of the week.

14. The method of claim 5 wherein the predetermined input criteria for determining the number of items n to be scanned comprises the date of the year.

15. The method of claim 5 wherein the predetermined input criteria for determining the number of items n to be scanned comprises the percentage of self-scans made by the shopper which were allocated to items returned to the shelf during shopping.

16. The method of claim 5 wherein the predetermined input criteria for determining the number of items n to be scanned comprises the measured dwell time between self-scans by the shopper.

17. The method of claim 5 wherein the predetermined input criteria for determining the number of items n to be scanned comprises scans of bar codes of preselected items determined to be associated with high pilferage.

18. In a self-service shopping checkout system wherein a shopper is provided with a self-scanning terminal for the scanning of the bar code of an item selected for purchase prior to depositing the item into a shopping cart, and wherein a list of items self-scanned by the shopper is compiled and made available to a cashier for surveillance and payment purposes, the improvement comprising a system for performing a security check to determine if the shopper has failed to scan an item prior to depositing the item into the shopping cart, said system comprising:

a) means for determining the number of items n to be scanned;

b) means for scanning each of n items selected from the shopper'"'"'s cart of items presented for purchase;

c) means for allowing the shopping transaction if each item selected for scanning is present on the list of self-scanned items compiled by the shopper; and

e) means for disallowing the shopping transaction if any item selected for scanning is not present on the list of self-scanned items compiled by the shopper.

19. A self-service shopping checkout system comprising

a) a plurality of portable self-checkout devices, each of said self-checkout devices to be used by a customer to scan a bar code located on an item to be purchased so as to record therein a list of such items to be purchased, each of said devices comprising bar code scanning means for scanning and decoding a bar code located on an item to be purchased, means for compiling a list of items scanned by said customer, and a data output port for allowing transfer of said scanned item list to an associated data port located external to said portable device;

b) a stationary dispenser unit for the releasable containment of said plurality of portable self-checkout devices, said dispenser unit comprising;

(i) a plurality of device containment slots, each of said slots being configured for releasable containment of a mating self-scanning device, each of said slots having associated therewith a data input port suitable for mating with a data output port located on a portable self-checkout device; and

(ii) a printer for printing a tally list of items scanned for purchase by said shopper, said tally list being supplied by a self-checkout device after said self-checkout device is returned to a device containment slot after being used by a shopper, said tally list further comprising a two-dimensional bar code encoded with said items scanned by said shopper, a unique identification record associated with said shopper, and the number of items scanned by said shopper;

c) a plurality of point of sale terminals, each of said point of sale terminal comprising;

(i) bar code reading means for reading said two-dimensional bar code from a tally list presented to a cashier operating said point of sale terminal, said bar code reading means providing as output data signals representing said items scanned by said shopper, said unique identification record associated with said shopper, and said number of items scanned by said shopper;

said bar code reading means also configured so as to scan select items presented for checking by said cashier;

(ii) means for determining, as a function of said number of items scanned by said customer and an internally stored check number unique to said customer, the number of items n to be scanned by the cashier;

(iii) means for comparing the identity of the items scanned by said cashier with the list of items scanned by said customer;

(iv) means for allowing the shopping transaction if each item selected for scanning by the cashier is present on the list of self-scanned items compiled by the shopper; and

(v) means for disallowing the shopping transaction if any item selected for scanning by the cashier is not present on the list of self-scanned items compiled by the shopper.

20. A method for enhancing the accuracy of a self-check out system wherein a customer selects a plurality of items for purchase and registers the plurality of items with a portable terminal, said method comprising the steps of:

(a) automatically computing the probability that the customer has failed to properly register the plurality of items selected for purchase with the portable terminal, and (b) selectively scanning a number of the customer selected plurality of items less than all the customer selected plurality of items if the probability that the customer has failed to properly register the plurality of selected items exceeds a predetermined acceptance value.

21. The method of claim 20 wherein the step of analyzing the probability that a customer has failed to properly register the plurality of selected items with the portable terminal comprises the steps of:

(a) storing a customer'"'"'s prior purchasing history; and

(b) comparing the plurality of items registered with the portable terminal by the customer to the customer'"'"'s prior purchasing history.

22. The method of claim 21 wherein the predetermined acceptance value is modified to reflect the availability of an attendant to perform the step of selectively scanning the number of selected items within a predetermined time period.

23. The method of claim 22 wherein the step of determining the availability of the attendant comprises the step of determining queue length for the attendant.

24. The method of claim 22 wherein the predetermined acceptance value is modified to reflect a high pilferage rate condition indicative of a time period of historically high pilferage rates for the self-checkout system.

25. The method of claim 20 wherein the portable terminal includes a means for unregistering previously registered items, and the step of analyzing the probability that a customer has failed to properly register the plurality of selected items with the portable terminal comprises the steps of:

(a) determining a registered item dwell time for each of the plurality of selected items registered with the portable scanner;

(b) determining an unregistered item dwell time for items registered with the portable terminal by the customer and subsequently unregistered with the portable terminal; and

(c) comparing the dwell times for registered and unregistered items.

26. The method of claim 20 wherein the step of analyzing the probability that a customer has failed to properly register the plurality of selected items with the portable terminal comprises the step of modifying the predetermined acceptance value to reflect the number of times the customer has previously had items selectively scanned without an incident of error in registering items selected for purchase with the portable terminal.

27. An apparatus for performing the method of claim 20 wherein said apparatus is a computer in communication with a plurality of portable terminals having an integrated bar code reader.

28. A method for selectively checking a plurality of items collected by a customer with a portable scanner used to perform a self-checkout function, said method comprising the step of determining a probability of erroneous registration for the plurality of items collected by the customer with the portable terminal relative to an acceptable risk value in accordance with the following steps:

(i) determining the customer'"'"'s historical erroneous registration rate using a customer'"'"'s prior purchasing history including a record of erroneous registrations detected during a selective scanning check; and

(ii) modifying the acceptable risk value by at least one secondary factor.

29. The method of claim 28 wherein the at least one secondary factor is an evaluation of the availability of an attendant to perform a selective scanning operation.

30. The method of claim 29 wherein the at least one secondary factor further comprises a non-customer specific error history record for the self-checkout system.