GB2606754A

GB2606754A - Detection of under-scanning at a point-of-sale

Info

Publication number: GB2606754A
Application number: GB2107208.7A
Authority: GB
Inventors: Morris Joseph
Original assignee: Tj Morris Ltd
Current assignee: Tj Morris Ltd
Priority date: 2021-05-20
Filing date: 2021-05-20
Publication date: 2022-11-23
Also published as: GB202107208D0

Abstract

A point-of-sales (POS or EPOS) system comprises a reader (26) for reading product codes from goods (14), and a database of goods (42) referenceable using the product codes. At least one sensor (44) is used to measure goods presented for purchase at the POS. A processing system determines the volume of the goods from measurements output by the sensor to provide a measured goods volume; receives the product codes of the goods presented to the reader; retrieves, from the database of goods based on the received product code(s), product data comprising a record of the volume of the goods, or data from which the volume of the goods is able to be determined; determines a scanned goods volume from the product data; and carries out a comparison of the measured goods volume with the expected scanned goods volume, to detect possible under-scanning, sweet-hearting or other illegitimate scanning actions. The sensor 44 may be an optical sensor, a depth sensor or a time of flight camera. A depth-sensing sensor responsive only to items in a planar field of view may be installed on the conveyor with the movement of the conveyor also being used to determine the volume of goods.

Description

DETECTION OF UNDER-SCANNING AT A POINT-OF-SALE

The present invention concerns measures for detection of under-scanning at the point-of-sale in a retail outlet.

The term "retail outlet" refers herein to any premises where retail sale of goods is carried out and includes any form of shop (or in US English, store) including supermarkets and department stores.

In a retail outlet, the customer selects goods for purchase and takes them to a point-of-sale terminal where the charge is calculated and payment is made. In a modern retail outlet each item of goods for sale typically carries a machine-readable code to be read by a reader at the point-of-sale to identify the product, and in this way the point-of-sale device is able to retrieve the cost of the item from a database and add it to the charge to be made to the customer, and to facilitate other functions such as obtaining product information for the customer receipt, enabling updating of the store's stock inventory, and so on. The machine-readable code typically comprises a visible marking to be optically read at the point-of-sale. Universal Product Codes ("UPCs") based on bar codes have been very widely used in this respect but OR ("Quick Response") codes are also used, and there have over the years been many proposals for use of other types of machine-readable codes or tags.

At the point-of-sale, each item for purchase typically needs to be scanned -that is, it needs to be individually presented to a reader so that its code can be read. Where the machine-readable code takes the form of a barcode or OR code, the items need to be moved through the field of view of a suitable optical scanner with the code presented to the scanner. This scanning process may be carried out by a till operative or (in the case of "self-checkout") by the customer themselves. The reader may take the form of a laser scanner, or it may use an imaging device such as a digital camera.

Supermarkets and many other retail outlets often provide a conveyor at the point-of-sale for conveying the goods to a till operative. The goods are placed on the conveyor, typically by the customer. A simple automatic control system is provided to control movement of the conveyor, using a "magic eye" arrangement arranged close to the till operative. This may comprise a light emitter directed across the conveyor onto a light detector, with associated electronics which provide that while the light detector is exposed to the light from the emitter, the conveyor runs, but when an item on the conveyor blocks the light from the emitter the resultant change in the output of the light detector leads to the conveyor being stopped. In this way, the conveyor is arranged to deliver an item to the till operative, and then to stop until that item is removed from the conveyor.

The till operative takes the items one-by-one from the conveyor and passes them through a scanning area (the field of view of the reader) to enable the code to be read. Known codes in the form of UPCs include a check digit to enable misreads to be detected. After the code has been read, a lookup is made in a database to identify the product and retrieve its cost. If the check digit matches the remainder of the code and the code read from the product matches an item in the database then a signal is given to the till operative, typically in the form of an audible "beep", that the product has been scanned and recognised and can be passed to a downstream area which will be referred to herein as the "collection zone", from which the customer can collect the item.

The system can be defrauded by the till operative, in a manner that enables items to be received into the possession of the customer without being paid for. In under-scanning, the till operative passes an item from the conveyor to the collection zone without scanning it. Hence the cost of the un-scanned item is not added to the customer's bill. Deliberate under-scanning is sometimes referred to as "sweethearting" because typically the perpetrator is the till operative but the direct beneficiary is the customer. Under-scanning can also happen accidentally, e.g. due to a simple lack of care on the part of the till operative.

To move the item from the conveyor to the collection zone without it being scanned, the till operative may for example orient the item such that the code is not presented to the reader, or may move the item along a path that does not include the field of view of the reader, or may wholly or partly cover the code. For example, a fingertip may be placed over part of a barcode or OR code, making a full read impossible.

Some measures are known for detection of under-scanning. Refer in this regard to W02012/170551, Stoplift, Inc. The section of this document referring to prior art explains one known technique based on analysis of "scan gaps" -the intervals of time between one scan and the next. This is explained to be an unreliable method of detection, given the natural variability in scan gaps. The main part of the description of W02012/170551 deals with a process involving an "analysis engine" which monitors data generated in the retail environment and detects "trigger events" as a basis for providing alerts, which may be security related. Embodiments are described in which the analysis engine analyses video feeds to monitor the activity of the cashier and customer and tracks items and a "cart" (shopping trolley, in the UK) before, during and after a transaction, in order to determine when an item present in the video stream is not properly recorded in the transaction log generated at the point-of-sale. Another example of a system for detecting sweethearting by analysis of video footage and comparison against point-of-sale transaction data is provided by US8448858 (Kundu eta!) But the analysis of video footage needed in order to detect sweethearting is challenging in itself, not only because of the complex visual environment in which the video analysis must be carried out, but also because of the volume of video data involved. Most retail outlets of any size have multiple tills operating for hours each day. The processing capacity needed for worthwhile monitoring is potentially large and hence expensive.

A different, simpler and/or superior means of detection of under-scanning is therefore desirable.

The present invention provides a sales system, a method of detecting under-scanning, and a computer program product according to the appended claims.

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an overhead view of a point-of-sale installation forming part of a sales system embodying the present invention; and Figure 2 is a stylised view of part of the same point-of-sale installation The illustrated point-of-sale installation 10 comprises a conveyor 12 onto which goods 14 to be purchased are typically loaded by a customer 16. The conveyor 12 is controllable by a sensor arrangement having a light source 18 arranged to project a light beam, whose path is not normally visible but is represented by a line 20 in the drawings, across the conveyor 12 onto a light sensor 22.

The till operative takes the goods 14 one item after another from the conveyor 12 and offers them to a reader 26. In the present example the reader 26 is an optical device for reading bar codes and/or OR codes, although as explained above other forms of reader technology may be used for reading product codes and these may be adopted in other embodiments of the present invention. The reader 26 is arranged between the conveyor 12 and a collection zone 28 (also referred to commonly as the "bagging area") to which the till operative passed the goods 14 after they have been read, and from which the customer can collect the goods for bagging and removal.

In the normal course of events each item of goods removed from the conveyor 12 is presented to the reader 26 and, as described above with reference to the prior art, is scanned. Its product code is read and validated (e.g. based on a checksum in the product code, and on a comparison of the product code against a product database to ensure that the code read by the reader 26 is valid). A signal (usually an audible signal) is provided to the till operative that a valid read has been carried out and the item of goods is placed in the collection zone. If there is an invalid code read for some reason then a different signal is given to the till operative to direct him/her to present the item once more to the reader 26. In the event of repeated failure to read the product code, the till operative 24 may manually input the product code using a keypad, or may seek assistance. Certain goods (e.g. loose fruit and vegetables) may carry no product code, but for those the point-of-sale device provides some other means of identification, e.g. using symbols on a bank of switches, often in conjunction with a scale for weighing the goods and so enabling them to be priced.

Each instance of valid reading of a product code, or of input of a product identification by another means, will be referred to herein as a "product read". Product reads are of course routinely timed and logged, and are used in compiling the total billed to the customer. Data relating to product reads will be referred to as "product read data", and this data is routinely collected by the point-of-sale system. The electronics at the point-of-sale installation 10 are networked to a computer system 40 which receives the product-read data from the points of sale, and which implements a variety of functions for the retail outlet, typically including recordal of stock levels. The computer system 40 typically stores a range of data about stocked goods in a database 42.

In embodiments of the present invention to be described below, goods 14 presented for purchase at the point-of-sale 10 are optically measured to provide a determination of their cubic volume. Records of the goods' volumes are also retrieved from the database 42 by reference to the product codes of the goods read by the scanner 26. If there is a discrepancy between the volumes determined by these two methods, it may have arisen because goods have passed through the point-of-sale installation without being scanned. So in response to such a discrepancy, an alert is provided which may for example be used to prompt a human operative to make enquiries, perhaps including review of video footage of the point-of-sale installation 10, to try to determine whether intentional under-scanning is taking place.

In the present embodiment, measurements of the goods 14 used in calculation of their volume are made using a sensor 44, which is omitted from Figure 1 but seen in Figure 2. This is an optical sensor, in the present example, although the term "optical" as used in this context does not exclude sensing of electromagnetic wavelengths outside the range of sensitivity of the human eye, and the sensor 44 may for example be responsive to infra-red light.

Figure 2 shows the sensor 44 arranged to image goods 14 on the conveyor 12, being mounted above the conveyor 12. Additionally or alternatively, within the scope of the present invention, the sensor 44 may be arranged to image goods 14 at or downstream of the reader 26, e.g. in the collection zone 28. Some point-of-sale installations have a second conveyor in the collection zone 28, and a sensor 44 may be provided to image goods on that conveyor.

Goods 14 need to be measured in three dimensions to enable their volume to be calculated. In the present embodiment, the sensor 44 is a depth-sensing sensor, which is to say that it is capable of determining the distance between a surface in its field of view and itself. A time-of-flight type of camera is well-suited to this purpose and is used in the present embodiment, but other suitable technologies at the time of writing include structured light-type systems, Lidar, stereoscopic imaging systems, etc. The sensor 44 may, in certain embodiments of the invention, be a 3D imaging device, arranged and configured to have a field of view covering an area of the path taken by the goods 14. For example, the field of view may take in all or part of the length of the conveyor. However, there would be a processing burden involved in analysing 3D images of this type. Also even with a 3D imaging device, a single viewpoint of the goods is not necessarily sufficient to enable their volume to be determined.

In the present embodiment, the depth-sensing sensor 44 is of a different type: it has an essentially planar field of view 46 extending across the path taken by the goods 14, and more specifically across the width of the conveyor 12. Thus the depth-sensing sensor 44 can be thought of as a "Y-Z" sensor, where the Z axis runs along the direction from the sensor 44 to the conveyor 12 and the "Y" axis runs across the width of the conveyor 12. The depth-sensing sensor 44 may be a pixel-type sensor capable of imaging the whole field of view simultaneously, such as a time of flight camera, or it may for example be configured to scan across the Y axis. Laser depth-sensing devices of this scanning type are known to the skilled person.

At any point in time, the depth-sensing sensor 44 provides a profile of the 2-dimensional shape formed by the goods 14 upon the conveyor 12, in the Y-Z plane 46. From this, the cross-sectional area of the goods 14 in the Y-Z plane is determined by the present system. In itself, this does not provide a basis for determining the goods' volume. But over time, each of the goods 14 moves through the field of view of the sensor 44, as the conveyor 12 advances, making it possible to calculate the goods' volume. For this purpose, the system needs not only the Z-Y data from the sensor 44, but also X-axis data -a measure of the advancement of the conveyor 12/goods 14 over time. This may for example be obtained by determining the movement of the conveyor from its drive mechanism (e.g. by counting revolutions in a rotary drive mechanism, or from an encoder connected to the conveyor's motor or drive by the conveyor belt), or it may be obtained using an imaging sensor responsive to conveyor movement, such as an overhead camera from whose output conveyor advancement can be calculated.

The cubic volume of the goods 14 is thus calculated from a sequence of measurements of the cross-sectional area of the goods 14 in the Y-Z plane, obtained from the depth-sensing sensor 44, in combination with a determination of the advancement of the conveyor between each such measurement. The term "measurement" as used here and in the appended claims, does not of course imply that the goods are compared against a scale such as a ruler. Rather, it refers to the process by which the shape and size of the goods are determined using the sensor 44.

As explained above, a further determination of the volume of the goods 14 is made by reference to the goods' product codes, as read by the reader 26. The product code uniquely identifies each product that is properly scanned by the reader 26. The volume of each item of scanned goods is retrieved from the database 42 by reference to the product code. An EPOS system typically stores dimensions of each item of goods, in which case it may be these dimensions that are retrieved, with goods volume being calculated from the stored dimensions. Alternatively goods may be measured when they are added to the database, in order that their volume is known. It is also possible for s system of the present type to learn the volumes of goods itself, based on the data provided by numerous tills.

The processing needed to make the two determinations of volume may be carried out in the computer 40 networked to the point-of-sale installation and/or it may be carried out in whole or in part by a computer situated at the point-of-sale 10. In either case, the system uses the two determinations of the goods' volume to obtain an indication of whether under-scanning may be taking place. This determination may be made by using a total volume of goods purchased by the customer. In such an embodiment, the system may sum the volumes of all the customer's goods as obtained by reference to the scanned product codes to obtain a scanned goods volume, and calculate the total volume of the goods passed through the field of view of the depth-sensitive sensor 44 during the transaction, to obtain a measured goods volume. If the measured goods volume exceeds the scanned goods volume by more than a chosen margin then an indication may be provided by the system of possible under-scanning.

An alternative is to make more frequent comparisons between scanned and measured goods volumes, possibly item-by-item.

An exact match between measured and scanned goods volumes is not expected, for a variety of reasons. Some items, such as unpackaged produce, those sold in non-rigid containers such as bags and so on, may have a volume that is variable or hard to accurately determine. Some items may be wrongly measured, perhaps because they topple whilst moving through the field of view of the depth-sensing sensor 44. So the system may be configured to provide an indication of possible under-scanning only in response to a large discrepancy in the two goods volumes.

But sweethearting by till operatives is often a repeated behaviour by the individual concerned. The objective for the management of the retailer is typically to identify the individuals involved. The present system may be configured to seek patterns in the volume discrepancies, in order to find those individuals. For instance, if data for a certain till operative shows significant discrepancies more often than expected, that may be a reason for investigating further whether that individual is engaged in sweethearting.

Typically, the present system will not be intended to, nor capable of, making a positive determination that deliberate under-scanning is taking place. Rather, it will provide an indication of possible under-scanning which may be used as a basis for further enquiry. For example, the response to such an indication may be for a human operative to review video footage of the relevant transaction, to look for suggestions of deliberate under-scanning.

Claims

CLAIMS1. A sales system for use in a retail outlet, the system comprising a reader for reading product codes from goods presented to the reader, a database of goods referenceable using the product codes, at least one sensor configured to measure goods presented for purchase at the point-of-sale, and a processing system configured to: make a determination of the volume of the goods from measurements output by the sensor to provide a measured goods volume; receive the product codes of the goods presented to the reader; retrieve, from the database of goods and by reference to the received product code(s), product data comprising a record of the volume of the goods, or comprising data from which the volume of the goods is able to be determined; determine a scanned goods volume from the product data; and carry out a comparison of the measured goods volume with the scanned goods volume, as a basis for recognition of possible under-scanning.
2. A sales system as claimed in claim 1 in which the sensor is an optical sensor.
3. A sales system as claimed in claim 1 or in claim 2 in which the sensor is depth-sensing.
4. A sales system as claimed in any preceding claim in which the sensor is a time-of-flight camera.
5. A sales system as claimed in any preceding claim in which the sensor is a depth-sensing sensor responsive only to items in a planar field of view which contains the sensor.
6. A sales system as claimed in any preceding claim in which the sensor is arranged to sense goods on a conveyor at the point-of-sale.
7. A sales system as claimed in any of claims 1 to 4 in which the sensor is arranged to sense goods on a conveyor at the point-of-sale, the sensor is a depth-sensing sensor responsive only to items in a planar field of view which contains the sensor and which extends across the conveyor, and in which the processing system is configured to receive a signal indicative of movement of the conveyor, and to make the determination of the measured goods volume based on both the measurements output by the sensor and the movement of the conveyor.
8. A method of detecting under-scanning at a retail outlet, implemented in a system that comprises a reader at a point-of-sale for reading product codes from goods presented to the reader, and a database of goods referenceable using the product codes, the method comprising: measuring goods presented for purchase at the point-of-sale in the course of a retail transaction using a sensor and making a determination of the volume of the goods from the measurements to provide a measured goods volume; presentation of one, some, or all of the goods to the reader in the course of the retail transaction and reading of the presented goods' product code(s) by the reader; retrieving, from the database of goods and by reference to the product code(s) read from the goods by the reader, product data comprising a record of the volume of the goods, or a record of data from which the volume of the goods is able to be determined; determining a scanned goods volume from the product data; and carrying out a comparison of the measured goods volume with the scanned goods volume, as a basis for recognition of possible under-scanning.
9. A method in which the sensor is as claimed in claim 8 in which the sensor is an optical sensor.
10. A method as claimed in claim 8 or claim 9 in which the sensor is depth-sensing.
11. A method as claimed in any of claims 8 to 10 in which the sensor is a time-of-flight camera.
12. A sales system as claimed in any preceding claim in which the sensor is a depth-sensing sensor responsive only to items in a planar field of view which contains the sensor.
13. A method as claimed in any of claims 8 to 12, comprising sensing the goods on a conveyor at the point-of-sale using a depth-sensing sensor responsive only to items in a planar field of view which contains the sensor and which extends across the conveyor, detecting movement of the conveyor, and making the determination of the measured goods volume based on both the measurements output by the sensor and the movement of the conveyor.
14. A computer program product for running on a processing system of a sales system in a retail outlet, the system comprising a reader for reading product codes from goods presented to the reader, a database of goods referenceable using the product codes, at least one sensor configured to measure goods presented for purchase at the point-of-sale, and the computer program comprising instructions to cause the processing system to: make a determination of the volume of the goods from measurements output by the sensor to provide a measured goods volume; receive the product codes of the goods presented to the reader; retrieve, from the database of goods and by reference to the received product code(s), product data comprising a record of the volume of the goods, or comprising data from which the volume of the goods is able to be determined; determine a scanned goods volume from the product data; and carry out a comparison of the measured goods volume with the scanned goods volume, as a basis for recognition of possible under-scanning.