Dynamic-range scale

Abstract

A weighing system for use in retail transactions comprises a weighing platform characterized by a weighing-platform weight range corresponding to a first level of precision and extending from a zero weight-value to a weighing-platform maximum value. A controller is configured to open and operate a virtual scale that uses the weighing platform and is characterized by a virtual-scale weight range corresponding to a second level of precision and smaller than the weight-platform weight range. Opening the virtual scale includes setting, at a first time, a respective virtual zero-weight value and a respective virtual-scale maximum value for the virtual-scale weight range. Operating the virtual scale includes calculating, at a second time, a current-item weight for a current item added to the weighing system after the first time.

Description

[0001] DYNAMIC-RANGE SCALE

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to weighing devices and assemblies for use in retail commerce, and in particular to devices and assemblies suitable for use in trade as well as for general weighing purposes.

[0004] BACKGROUND

[0005] Industry standards and regulations require specific levels of precision for scales used in trade. For example, in many jurisdictions, a scale used to weigh products is constrained to having a number of divisions that lies within a specified range, and the range can limit the overall weighing capacity of such a scale to a weight that is less than that of a typical shopping cart or checkout station. Moreover, scales used in trade are often required to have a tare feature which ‘zeroes out’ the scale before each new product is weighed. At the same time, autonomous and semi- autonomous shopping carts and checkout stations have use for a weighing system that performs general weighing outside the limitations of the tare-capable scale that can be approved for use in trade. As an example, such weighing systems are used to provide a kind of security to ensure that products are not added to shopping carts or shopping bags without being recognized or otherwise registered by the retail system. Prior art approaches offer solutions to both needs but in separate devices: there are commercially available scales with tare functions approved for use in trade, and there are commercially available scales for use in shopping carts and checkout stations that are not approved for use in trade. Thus, there is a need for a weighing system that can provide both general weighing functions as well as meeting the requirements of scales that can be approved as legal for trade and for retail use.

[0006] SUMMARY

[0007] Embodiments of the present invention relate to weighing systems operating in multiple ranges in order to perform general weighing and allow regulated ‘legal for trade’ use. Embodiments also relate to mobile and non-mobile implementations of the weighing platform, e.g., in shopping carts and check-out stations.

[0008] According to embodiments of the invention, a weighing system for use in retail transactions comprises: (a) a weighing platform characterized by a weighingplatform weight range corresponding to a first level of precision, the weighingplatform weight range extending from a zero weight-value to a weighing-platform maximum value; and (b) a controller comprising one or more processors and a nontransient storage device having stored thereupon program instructions, wherein said program instructions, when executed by the one or more processors, cause the one or more processors to open and operate a virtual scale that uses the weighing platform and is characterized by a virtual-scale weight range corresponding to a second level of precision, the virtual-scale weight range being smaller than the weight-platform weight range. Opening the virtual scale includes setting, at a first time, a respective virtual zero-weight value and a respective virtual-scale maximum value for the virtual-scale weight range. Operating the virtual scale includes calculating, at a second time, a current-item weight for a current item added to the weighing platform after the first time.

[0009] In some embodiments, the weighing platform or weighing system is certifiable as legal for trade when opening and operating the virtual scale. In some embodiments, the weighing platform or weighing system is certifiable as legal for trade only when opening and operating the virtual scale.

[0010] In some embodiments, the setting of the virtual zero-weight value can include setting the virtual zero-weight value to equal a current gross weight registered by the weighing system at the first time. In some embodiments, the setting of the virtual zero-weight can include setting the virtual zero-weight value to be equal to a gross weight registered by the weighing system before the first time. In some embodiments, the gross weight registered by the weighing system before the first time can be a gross weight registered at the end of a previous opening and operating of the virtual scale.

[0011] In some embodiments, the opening of the virtual scale can be in response to a user input. In some embodiments, the opening of the virtual scale can be in response to a sensor input. In some embodiments, the opening of the virtual scale can be in response to a detected change in a current gross weight.

[0012] In some embodiments, the calculating of the current-item weight at said second time cab include calculating a difference between a current gross weight registered by the weighing system and the virtual zero-weight value for the virtual- scale weight range.

[0013] In some embodiments, the virtual-scale maximum value can be constrained during the setting thereof such that the sum of the current gross weight at the first time and of the set virtual-scale maximum value is not higher than the weighing-platform maximum value.

[0014] In some embodiments, the second level of precision can be greater than or equal to the first level of precision. In some embodiments, the virtual-scale weight range and corresponding second level of precision can define, in combination, at least 500 divisions. In some embodiments, the virtual-scale weight range and corresponding second level of precision can define, in combination, not more than 10,000 divisions. In some embodiments, the weighing-platform weight range and corresponding first level of precision can define, in combination, more than 10,000 divisions.

[0015] In some embodiments, the non-transient storage device can have stored thereupon further program instructions which, when executed by the one or more processors, cause the one or more processors to calculate a current-item price using a current-item identification. In some embodiments, the current-item price can be calculated on a per-weight basis. In some embodiments, the current-item price can be calculated on a per-unit basis. In some embodiments, the weighing system can be configured to send the current-item weight to a retail transaction system for calculating a current-item price.

[0016] In some embodiments, the weighing system can additionally comprise a display device configured to display the current-item weight, and optionally a calculated current-item price. In some embodiments, the controller can be configured to create an alert status in response to a detected change in a current gross weight in the absence of a currentitem identification.

[0017] In some embodiments, it can be that the current gross weight is registered by the weighing system at said second time in accordance with one of a stability rule and a duration rule.

[0018] In some embodiments, a shopping cart comprises a weighing system, or at least a weighing platform, in accordance with any of the foregoing embodiments. In some embodiments, a checkout station comprising a weighing system, or at least a weighing platform, in accordance with any of the foregoing embodiments.

[0019] A method is disclosed, in accordance with embodiments of the invention, for operating a weighing system that comprises a weighing platform characterized by a weighing-platform weight range corresponding to a first level of precision; the weighing-platform weight range extends from a zero weight-value to a weighingplatform maximum value. The method comprises: (a) opening a virtual scale that uses the weighing platform and is characterized by a virtual-scale weight range corresponding to a second level of precision, the virtual-scale weight range being smaller than the weight-platform weight range, wherein the opening includes setting, at a first time, a virtual zero-weight value for the virtual-scale weight range to be equal to a current gross weight registered by the weighing system; and (b) operating the virtual scale to determine a current-item weight, the operating including calculating, at a second time, a current-item weight for a current item added to the weighing platform after the first time, by subtracting the virtual zero-weight value for the virtual-scale weight range from a current gross weight registered by the weighing system.

[0020] According to embodiments of the invention, a shopping cart comprises (a) a base portion comprising a plurality of wheels supporting the base portion, and one or more product-receiving units for receiving products therein or thereon; (b) a weighing platform comprising one or more load cells, the weighing platform disposed and configured to measure a weight of at least one of the one or more product-receiving units and any products contained therein or thereon; and (c) a controller comprising one or more processors and a non-transient storage device having stored thereupon program instructions, wherein said program instructions, when executed by the one or more processors, cause the one or more processors to: (i) monitor weight measurement data registered by the weighing system; (ii) analyze the weight measurement data to detect noise having a mechanical cause; and (iii) creating an alert status in response to the detection.

[0021] In some embodiments, the detecting can include detecting that the noise meets at least one of an amplitude criterion and a pattern criterion.

[0022] In some embodiments, the mechanical cause can include a rolling movement of the shopping cart. In some embodiments, the mechanical cause can include a physical interaction between a person and the shopping cart.

[0023] In some embodiments, creating the alert status can include suspending a function of the weighing platform and / or of the controller. In some embodiments, the suspended function can include a function that is part of a retail transaction.

[0024] In some embodiments, it can be that said program instructions, when executed by the one or more processors, additionally cause the one or more processors to cancel said alert status and / or said suspension upon detection of a reduction in the amplitude of said noise below the amplitude criterion or of a change in the noise to no longer meet the pattern criterion .

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The invention will now be described further, by way of example, with reference to the accompanying drawings, in which the dimensions of components and features shown in the figures are chosen for convenience and clarity of presentation and not necessarily to scale. In the drawings:

[0027] Fig. 1 A is a schematic representation of a weighing system including selected connected devices, according to embodiments of the present invention.

[0028] Fig. IB schematically illustrates components of a weighing platform, according to embodiments of the present invention. Fig. 2 is a schematic comparison between the weight range of a weighing platform and the virtual weight range of a virtual scale using the weighing platform, according to embodiments of the present invention.

[0029] Figs. 3 A and 3B schematically illustrate operation of the weighing platform of Fig. 2 and respective virtual scales, according to embodiments of the present invention.

[0030] Fig. 4 schematically illustrates examples of opening a virtual scale, according to embodiments of the present invention.

[0031] Fig. 5 schematically illustrates an example of constraining the virtual weight range of a virtual scale based on the maximum weight of a weighing platform, according to embodiments of the present invention.

[0032] Fig. 6 shows an exemplary block diagram of electronic circuitry hardware according to embodiments of the present invention.

[0033] Fig. 7 schematically illustrates operation of the weighing platform of Fig. 1A and a respective virtual scale, according to embodiments of the present invention.

[0034] Fig. 8 schematically illustrates the operation of the weighing platform of Fig. 1 A and a respective virtual scale in an alert status, according to embodiments of the present invention.

[0035] Figs. 9A and 9C schematically illustrate sources of mechanical noise causing respective alert statuses, according to embodiments of the present invention.

[0036] Fig. 9B shows an alert status for a weighing platform, according to embodiments of the present invention.

[0037] DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0038] The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. Throughout the drawings, like-referenced characters are generally used to designate like elements. Subscripted reference numbers (e.g., 1 Oi) or letter-modified reference numbers (e.g., 100a) may be used to designate multiple separate appearances of elements in a single drawing, e.g. 10i is a single appearance (out of a plurality of appearances) of element 10, and 100a is a single appearance (out of a plurality of appearances) of element 100.

[0039] Embodiments of the invention relate to weighing systems and weighing platforms, and retail assemblies comprising them such as, for example, shopping carts and checkout stations. Other implementations employing the disclosed weighing systems include, and not exhaustively: autonomous vending machines and displays, and vending carts. In the embodiments, the weighing systems are configured to open and operate virtual scales that use the physical components of the weighing platform while creating virtual weight ranges. The virtual scales are designed to be approved for use in trade in various jurisdictions, which can mean, inter alia, having a number of weight divisions falling within a specified range, and a tare function.

[0040] The weighing systems can also be used to create alert statuses, which may or may not be communicated to a user. For example, when the weight of an unidentified or unregistered item is detected, or when the weighing platform experiences mechanical noise of a specific type or beyond a specified amplitude or duration, a visual or audible alarm can be communicated to the user.

[0041] Referring now to the figures, and in particular to Figs. 1 A and IB, a weighing platform 50 includes a load cell assembly 55. In the non-limiting example of Fig. 1 A, the weighing platform 50 includes a load platform 57 which transfers the load, e.g. of products placed thereupon, to the load cell assembly 55. In some implementations, the load platform 57 comprises an upper frame for attachment to a shopping cart, for example, to a basket and / or shelf portion of a shopping cart. In some implementations, the load platforms comprises a flat surface for placement thereupon of products to be weighed. The weighing platform 50 of Fig. 1 A also includes a support platform 52, which supports the load cell assembly 55. In some implementations, the support platform 52 comprises a lower frame for attachment to a shopping cart, for example to a base of a shopping cart. In some implementations, the support platform 52 can be part of a permanent base, e.g., of a checkout station.

[0042] A weighing system 100 according to embodiments includes the weighing platform 50 and a controller 40. The controller 40 can be integrated with the load cell assembly 55, as shown schematically in Fig. IB. The load cell assembly 55 of Fig. IB includes a flexure arrangement and one or more strain gages for translating the mechanical strain at or downstream of the flexure to an electrical signal which is processed by electronic circuitry, which can optionally be integrated with the controller 401; other examples of load cell assemblies can have different arrangements. While the weighing platform 50 is illustrated as including exactly one load cell assembly 55, this is only for convenience, and in other examples the weighing platform 50 includes multiple load cell assemblies, for example, 2, 3 or 4 load cell assemblies. In one example (not shown), the weighing kit includes two load cell assemblies, and the electronic circuitry is configured, e.g., arranged and / or programmed, to receive inputs from the two load assemblies. In said example, the load cell assemblies may be less robust physically than that used in the singleassembly versions. In some examples, the load cell assemblies can include multiple prismatic load cells. In other examples, multiple weighing platforms 50 can be deployed in a single shopping cart or checkout station, or within a single weighing system 100.

[0043] In some designs, e.g., as shown schematically in Fig. 1 A, the controller 40 is not integrated with the load cell assembly 55 but is in communication with the load cell assembly (or assemblies).

[0044] Fig. 2 shows a block diagram of an exemplary controller 40 of a weighing system 100. The term “controller” is used to mean any hardware, software and / or firmware deployed in connection with, inter alia, data communication, programming, data processing, data storage, measurements, and / or calculations. In the instant example, the controller 40 can include, and not exhaustively, any or all of the components illustrated in Fig. 2: one or more computer processors 45; non-transient program storage 48 for storing therein program instructions for execution by the one or more computer processors 45; transient and / or non-transient data storage 49 for storing therein measurements, calculations, and / or historical data; a weighing module 43 for handling information received from the one or more strain gages (not shown) of respective load cell assemblies 55, e.g., for translating electric signals to weight information; and a communications module 47, e.g., for communicating information about weighing to a display 80 and / or to an external computer 78, e.g., the display 80 and the external computer 78 of Fig. 1 A, which can be located at a retail location, at a central server location, or in the cloud. A power source for the electronics can be provided but is not shown in Fig. 2.

[0045] Referring now to Fig. 3, a weighing platform 50 is characterized by a weight range extending from a zero weight-value ZEROPLATFORM to a weighing-platform maximum value for the weighing platform 50, MAXPLATFORM. In some embodiments, ZEROPLATFORM equals zero, and MAXPLATFORM equals at least 50 kg, e.g., 50-60 kg, or 50-70 kg, or 50-80 kg, or 50-90 kg, or 50-100kg; or at least 60 kg, e.g., 60-70 kg, or 60-80 kg, or 60-90 kg, or 60-100 kg; or at least 70 kg, e.g., 70-80 kg, or 70-90 kg, or 70-100 kg; or at least 80 kg, e.g., 80-90 kg or 80-100 kg; or at least 90 kg, e.g., 90- 100 kg; or more than 100 kg.

[0046] In some embodiments, the weighing platform 50 bears the weight of certain elements, e.g., one or more baskets and / or shelves, of a shopping cart or similar apparatus. In such embodiments, the weighing-platform maximum value for the weighing platform 50, MAXPLATFORM, also includes the weight of the shopping cart elements. In such embodiments, the weighing platform 50 can be provided with weighing devices such as load cells 52 sized for a higher maximum weight such that the effective weight range of the weighing platform 50 is not overly diminished. Thus, in such embodiments, the effective weight range (starting at the gross weight of the supported shopping cart elements and extending to the maximum value MAXPLATFORM, can equal at least 50 kg, e.g., 50-60 kg, or 50-70 kg, or 50-80 kg, or 50-90 kg, or 50- 100kg; or at least 60 kg, e.g., 60-70 kg, or 60-80 kg, or 60-90 kg, or 60-100 kg; or at least 70 kg, e.g., 70-80 kg, or 70-90 kg, or 70-100 kg; or at least 80 kg, e.g., 80-90 kg or 80-100 kg; or at least 90 kg, e.g., 90-100 kg; or more than 100 kg.

[0047] The weighing platform 50 is further characterized by a level of precision that in combination with the weight range can yield any number of divisions, for example at least 10,000 divisions. In a first example, the zero weight-value ZERO PLATFORM is equal to zero and the maximum value for the weighing platform, MAXPLATFORM, is equal to 50 kg. According to the first example, the level of precision is 5 gm, and thus the number of weighing divisions is 10,000. In a second example, the zero weightvalue ZERO PLATFORM is equal to zero, the maximum value for the weighing platform, MAXPLATFORM, is equal to 75 kg, and the weighing platform bears the weight of shopping cart elements weighing 5 kg. According to the second example, the level of precision is 5 gm per division, and thus the number of weighing divisions is 15,000, with the first 1,000 divisions being dedicated to the weight of the shopping cart elements. In jurisdictions in which the weighing platform 50 cannot be approved for use in trade when configured to operate with 15,000 divisions, the weighing platform 50 can nonetheless be used for unregulated purposes. For example, the weighing platform 50 can be used for ‘security’, e.g., for ensuring that each item added to a shopping cart or a customer container at a checkout station is accounted for in terms of identification and pricing of the item. In another example, a weighing platform 50 is characterized by a level of precision that in combination with the weight range yields fewer than 10,000 divisions.

[0048] Still referring to Fig.3, the controller 40 of the weighing system 100 is configured, e.g., programmed, to open and operate a virtual scale. The virtual scale uses the hardware of the weighing platform 50 and is characterized by a virtual-scale weight range that is smaller than the weight range of the weight-platform 50. In some embodiments, data related to the virtual scale is displayed on a display 80 which is in communication with the weighing platform 50. In some implementations, the display 80 comprises a hardware display provided in accordance with a regulatory requirement.

[0049] Opening the virtual scale includes setting not only the zero-value weight ZEROVIRTUAL for a virtual-scale weight range, but also a respective virtual-scale maximum value for the virtual-scale weight range, MAXVIRTUAL. In some embodiments, the virtual-scale maximum value of the virtual-scale weight range, MAXVLRTUAL, is set in accordance with standards and / or regulations related to weighing devices approved for use in trade. In some embodiments, the virtual scale operates at a number of weighing divisions that, in combination with the virtual-scale weight range, corresponds to a level of precision greater than the precision of the weighing platform 50 itself. This can be accomplished, for example, by providing a weighing platform 50 that is technically capable at operating at a higher level of precision than is required and / or implemented for general, i.e., not necessarily legal-for-trade, operation. In embodiments, the virtual scale comprises at least 500 divisions, and no more than 10,000. In an example, the level of precision is 2 gm per division, and the weight range (MAXVIRTUAL - ZEROVIRTUAL) is 15 kg, and thus the number of weighing divisions is 7,500.

[0050] Figs. 4 A and 4B illustrate use of a weighing platform 50 according to embodiments. Fig. 4A shows an example of the application of the virtual scale concept to a first item added by a user to a weighing platform 50, i.e., in a shopping cart or at a checkout station.

[0051] In an illustrative use case, the virtual zero-weight value ZEROVIRTUAL is set to equal a current gross weight registered by the weighing system 100 at the time. In some implementations, before the first item is placed on the weighing platform 50 as is illustrated in the example of Fig. 4A, the current gross weight can be zero, and the initial virtual zero-weight value ZEROVIRTUAL(I) can be set to zero. In some implementations, before the first item is placed on the weighing platform 50, the current gross weight registered by the weighing system 100 is the weight of one or more product-receiving elements of a shopping cart or checkout station, the weight of which is borne by the weighing platform 50, depending on the design of the weighing system 100 and of the shopping cart or checkout station. In such an implementation, the initial virtual zero-weight value ZEROVIRTUAL(I) is not set to zero but to the current gross weight, i.e., the weight of the shopping cart or checkout station elements which are a load on the weighing platform 50. Because the weight of the apparatus of any specific given shopping cart or checkout station is a constant, the weighing system 100 can be set, in some implementations, to automatically subtract out a constant weight. In any case the specific arithmetic calculations used to arrive at a current-item weight depend on software design.

[0052] In embodiments, the respective virtual-scale maximum value MAXVIRTUAL(I) for the first virtual-scale weight range is set when opening the virtual scale. The virtual- scale maximum value MAXVIRTUAL(I), in a non-limiting example, can be based on a ‘standard weight range’ for a virtual scale, one which can be applied to every opening of the virtual scale. In some embodiments, virtual scales can be opened with variable weight ranges; for example, a shopping cart may identify a specific department of a store and open a virtual scale with a smaller or larger weight range. In another example, a shopping cart or checkout station may open a virtual scale with a weight range based on an identification of a product, e.g., by use of a sensor. With the virtual scale open as illustrated in Fig. 4A, a current-item weight WEIGHTCURRENT-ITEM(I) for the first product 70i is registered by the weighing system 100.

[0053] Turning now to Fig. 4B, a second virtual scale window is opened for weighing a second item, product 70z. When the second virtual scale window is opened, the new virtual zero-weight value ZEROVIRTUAL(2) is set to the current gross weight registered by the weighing system 100; the new virtual maximum-weight value MAXVIRTUAL(2) of the second virtual scale window is set by adding the weight range for the weighing system’s virtual scale (a standard weight range or a variable weight range, as described above) to the current gross weight registered by the weighing system 100 - the new zero virtual-scale weight value for the new virtual scale. In practical terms, this is a ‘tare function’ that allows each subsequent item 70 to be weighed from a zero-weight value, i.e., a virtual zero-weight value. In other words, the weighing system 100 and its controller 40 is configurable to make every virtual scale window opening involve invoking a tare function. In some embodiments, the tare (‘zeroing’) function is already invoked after the weighing of an item is concluded and before the opening of a new virtual scale for the next item.

[0054] In the example of Fig. 4B, once the second item 70z is placed on the weighing platform 50, e.g., in a shopping cart comprising the weighing platform 50, the weight of the second current item, WEIGHTCURRENT-ITEM(2), is calculated by the controller 40. In some embodiments, the calculating includes subtracting the first current gross weight that was registered before the addition of the second item 70z from the new second current gross weight registered by the weighing system 100 from. The calculation can be made in other ways, depending on software design, but any method of calculating the difference between the current gross weight registered by the weighing system 100 and the virtual zero-weight value for the virtual-scale weight range results in the same arithmetic result. In some embodiments, the second current gross weight is registered after the conclusion of the weighing of the first item 70i, and in other embodiments the second current gross weight is registered substantially at the time that the second virtual scale window is opened but before the weighing of the second item 70z. The decision of when to register the second current gross weight can be based on software design and / or on what procedure is used for initiating the opening of a new virtual scale window. Regardless of when the current gross weight is registered, the result, after the weighing of any item, is the same second current gross weight.

[0055] In order to improve the accuracy and validity of a current gross weight registered in response to the addition of an item 70 to the weighing platform 50, a stability rule and / or a duration rule can be applied to weighing process of any item. A stability rule, according to embodiments, is a rule that governs when weight measurement data points have adequately reached a ‘steady state’ condition under which a determination of a weight can take place. As an example, it can be desirable to define a stability rule in which respective steady states for streams of weight measurement data-points are defined by respective response-amplitude thresholds. As is known in the art, the dynamic response to a weighing event, after an initial ‘shock,’ can have a long dying ‘tail’ of ever-decreasing oscillation about a mean. The mean (of a reaction force / weight or of a voltage input thereto) can be easily discernible as the amplitude of the oscillation continues to decrease, and at some point in time there is little additional precision to be gained by waiting for the dynamic response to stop oscillating completely. Thus the stability rule can be based on a height of the oscillation, i.e., height above the mean, reaching a threshold. Examples of suitable thresholds include absolute thresholds (e.g., in grams) and relative thresholds (e.g., as a percentage of the mean).

[0056] In some embodiments, applying a stability rule includes estimating bias in the weight measurement data-points and compensating for the estimated bias. The compensation can include cancellation of the bias. As an example, a time-series clustering algorithm can be applied to the received streams of weight measurement data-points in order to identify and quantify bias in the data-points. The results can be compared with historical, i.e., learned and / or stored bias data, and the historical bias data can be updated accordingly so as to create an updated bias estimation. A duration rule is similar to a stability rule but time-based rather than being based on analysis of weight measurement data points. An example of a duration rule is: ‘steady state is reached N seconds after the peak response to a weighing event.’

[0057] In embodiments, a weighing system 100 may inform a user, e.g., via a message on a display 80, that the user may now initiate the weighing of an additional item in a new virtual scale window, and when the user may not, e.g., because the requirements of a stability or duration rule have not yet been fulfilled.

[0058] Fig. 5 schematically illustrates several examples of initiating the opening of a new virtual scale. Two product items 70i, 70z are disposed on the weighing platform 50, and it is desired to open a third virtual scale window for a third product 70s. A first option, shown schematically in example (A) of Fig. 5, is that the weighing system 100 receives a user unput, e.g., by a user 90 tapping on a ‘new item’ button on the display 80. A second option, shown schematically in example (B) of Fig. 5, is that the weighing system 100 receives an input from a sensor; in the non-limiting examples shown, an optical sensor 35 identifies a product 70s on its way to be placed on the weighing platform 50, or identifies a hand gesture by a user 90. Anther example of sensor inputs, not illustrated, includes use of a product scanner, e.g., a barcode scanner, to initiate opening the virtual scale. A third option, shown schematically in example (C) of Fig. 5, is that the virtual scale opens in response to a detected change in a current gross weight by the placing of the product 70s on the weighing platform 50. Using the third option may require that the registering of the current gross weight on the weighing platform 50 takes place at or after the conclusion of the previous weighing event, e.g., after satisfying a stability rule or duration rule if one is applied, and not at the time of opening the virtual scale.

[0059] According to embodiments, a virtual-scale maximum value MAXVIRTUAL cannot exceed a weighing-platform maximum value MAXRLATFORM. When an attempt is made to open a virtual scale for which a virtual-scale maximum value MAXVIRTUAL would exceed the weighing-platform maximum value MAXRLATFORM, the virtual-scale maximum value MAXVIRTUAL can be replaced by a constrained virtual scale maximum value MAXCONSTRAINED, as shown schematically in Fig. 6.

[0060] Reference is now made to Fig. 7. In exemplary embodiments, the display 80 of a weighing system 100 is used, inter alia, to communicate to users real-time information about products 70 placed on the weighing platform 50. In the nonlimiting example of Fig. 7, the display device 80 is configured to display the currentitem weight calculated in the framework of the virtual scale, and optionally a calculated current-item price. In some implementations, the controller 40 is programmed to calculate the current-item price. The calculation of the current-item price can be based on product price data stored in a database accessible by the one or more processors 45 of the controller 40, e.g., the data storage 49 of the controller or the external computer 78 that is in communication with the controller 40. The currentitem price is calculated on a per-weight basis and uses the current-item weight calculated in the framework of the virtual scale, or alternatively is calculated on a per- unit basis. In some examples, calculating the current-item price on a per-unit basis means that the stored unit price becomes the current-item price in the case of a single unit added to the weighing platform 50. In some embodiments, the database accessible by the one or more processors 45 of the controller 40 includes standard item weights or statistical distributions of item weights, such that upon identification of an item, the controller is capable of determining that multiple instances of a single product have been added to the weighing platform 50. In an illustrative example, the item identified is a one-liter bottle of water, the current-item weight is two kilograms, and the current-item price includes the price for two one-liter bottles of water. In some embodiments (not illustrated), the display 80 facilitates an interface for a user to input a quantity of same-barcode items added. In some embodiments (not illustrated), the display 80 facilitates an interface through which the user can perform one or more functions such as, and not exhaustively: correcting a quantity, selecting an item for identification, and / or canceling the addition of an item removed from the weighing platform 50.

[0061] In some implementations, the calculation of a current-item price is performed not by the controller 40 of the weighing system 100 but by an external computer 78, e.g., of a retail transaction system, upon receiving the current-item weight sent from the weighing system 100.

[0062] The display 80 can be used in various circumstances to communicate an alert status to the user. Referring to Fig. 8, an alert status regarding an unidentified product added to the weighing platform 50 is shown. In the non-limiting example of Fig. 8, the controller 40 of the weighing system 100 is configured to create an alert status in response to a detected change in a current gross weight in the absence of a currentitem identification. In other words, whatever procedure is used for identifying a current product, e.g., bar-code scanning, image acquisition and processing, etc., an item placed on the weighing platform 50, e.g., in a shopping cart or other container, is not identified, and the weighing system 100 is unable to assign or calculate a currentitem price. In some implementations, resolution of this alert status is required before the weighing system 100 returns to the normal operation depicted, e.g., in Fig. 7.

[0063] In embodiments, another type of alert status can be created in response to noise detected in a stream of weight-measurement data points, and in particular noise having a mechanical origin. In some embodiments, the alert status is contingent upon the noise meeting or exceeding an amplitude criterion and / or meeting a pattern criterion, i.e., a pattern indicative of noise having a mechanical cause,.

[0064] Referring now to Fig. 9A, an exemplary shopping cart 120 includes a base portion 60 on wheels, and a basket 20 receiving products. In some embodiments, a shopping cart includes multiple product-receiving baskets and / or shelves. The weighing platform 50 in Fig. 9A is disposed to receive the weight of the basket 20 and of any products placed therein. The controller 40 (not shown in Fig. 9A) can be programmed to monitor weight measurement data from the weighing platform 50, and to analyze the weight measurement data to detect noise, including noise having a mechanical cause. When noise meeting specific criteria is detected, the controller 40 creates an alert status in response. For example, it can be desirable, or required in some embodiments, for a shopping cart 120 to be stationary when an item 70 is added and weighed by the weighing platform 50, either for purposes of greater precision or because it may be required by standards or by regulation. Fig. 9B shows an exemplary alert status displayed by the display 80 in the case of noise from a mechanical cause being determined to include a rolling movement of the shopping cart 120. Another source of noise having a mechanical origin that is likely to interfere with accurate weighing of an item is a user 90 directly or indirectly touching the weighing platform 50, as shown schematically in Fig. 9C. In some embodiments, one or more functions of the weighing system 100, such as opening and / or operating a virtual scale, registering a current weight, and / or identifying and / or pricing a current item, may be suspended until the alert is resolved by the cessation of the noise of mechanical origin and / or by the return of the weighing platform 50 to a steady-state condition. Yet another source of noise having a mechanical origin that is likely to interfere with accurate weighing of an item is a collision (not illustrated) between a shopping cart and a shelf or with another cart, or, in the case of a checkout station, of a shopping cart banging into the checkout station.

[0065] Referring now to Fig. 10, a method is disclosed for operating a weighing system 100 that comprises a weighing platform 50 according to any of the embodiments disclosed herein. According to the method, the weighing platform 50 is characterized by a weighing-platform weight range corresponding to a first level of precision and extending from a zero weight-value to a weighing-platform maximum value. As illustrated by the flowchart in Fig. 10, the method comprises at least the two method steps SOI and S02:

[0066] Step SOI includes opening a virtual scale that uses the weighing platform 50 and is characterized by a virtual-scale weight range corresponding to a second level of precision; the virtual-scale weight range is smaller than the weight-platform weight range. The opening of Step SOI includes setting, at a first time, a virtual zero-weight value for the virtual-scale weight range to be equal to a current gross weight registered by the weighing system 100.

[0067] Step S02 includes operating the virtual scale to determine a current-item weight. The operating of Step S02 includes calculating, at a second time, a currentitem weight for a current item added to the weighing platform 50 after the first time, by subtracting the virtual zero-weight value for the virtual-scale weight range from a current gross weight registered by the weighing system 50.

[0068] The present invention has been described using detailed descriptions of embodiments thereof that are provided by way of example and are not intended to limit the scope of the invention. The described embodiments comprise different features, not all of which are required in all embodiments of the invention. Some embodiments of the present invention utilize only some of the features or possible combinations of the features. Variations of embodiments of the present invention that are described and embodiments of the present invention comprising different combinations of features noted in the described embodiments will occur to persons skilled in the art to which the invention pertains.

Claims

CLAIMS1. A weighing system for use in retail transactions, the weighing system comprising: a. a weighing platform characterized by a weighing-platform weight range corresponding to a first level of precision, the weighing-platform weight range extending from a zero weight-value to a weighing-platform maximum value; and b. a controller comprising one or more processors and a non-transient storage device having stored thereupon program instructions, wherein said program instructions, when executed by the one or more processors, cause the one or more processors to open and operate a virtual scale that uses the weighing platform and is characterized by a virtual-scale weight range corresponding to a second level of precision, the virtual-scale weight range being smaller than the weight-platform weight range, wherein: i. opening the virtual scale includes setting, at a first time, a respective virtual zero-weight value and a respective virtual- scale maximum value for the virtual-scale weight range, and ii. operating the virtual scale includes calculating, at a second time, a current-item weight for a current item added to the weighing platform after the first time.

2. The weighing system of claim 1, wherein the setting of the virtual zero-weight value includes setting the virtual zero-weight value to equal a current gross weight registered by the weighing system at the first time.

3. The weighing system of claim 1, wherein the setting of the virtual zero-weight includes setting the virtual zero-weight value to be equal to a gross weight registered by the weighing system before the first time.

4. The weighing system of claim 3, wherein the gross weight registered by the weighing system before the first time is a gross weight registered at the end of a previous opening and operating of the virtual scale.

5. The weighing system of any one of claims 1 to 4, wherein the opening of the virtual scale is in response to a user input.

6. The weighing system of any one of claims 1 to 4, wherein the opening of the virtual scale is in response to a sensor input.

7. The weighing system of any one of claims 1 to 4, wherein the opening of the virtual scale is in response to a detected change in a current gross weight.

8. The weighing system of any one of the preceding claims, wherein the calculating of the current-item weight at said second time includes calculating a difference between a current gross weight registered by the weighing system and the virtual zero-weight value for the virtual-scale weight range.

9. The weighing system of any one of the preceding claims, wherein the virtual-scale maximum value is constrained during the setting thereof such that the sum of the current gross weight at the first time and of the set virtual-scale maximum value is not higher than the weighing-platform maximum value.

10. The weighing system of any one of the preceding claims, wherein the second level of precision is greater than or equal to the first level of precision.

11. The weighing system of any one of the preceding claims, wherein the virtual-scale weight range and corresponding second level of precision define, in combination, at least 500 divisions and not more than 10,000 divisions.

12. The weighing system of any one of the preceding claims, wherein the weighingplatform weight range and corresponding first level of precision define, in combination, more than 10,000 divisions.

13. The weighing system of any one of claims 1 to 13, wherein the non-transient storage device has stored thereupon further program instructions which, when executed by the one or more processors, cause the one or more processors to calculate a current-item price using a current-item identification.

14. The weighing system of claim 13, wherein the program instructions include instructions for both of calculating a current-item price on a per-weight basis and calculating a current-item price on a per-unit basis.

15. The weighing system of any one of claims 1 to 12, wherein the weighing system is configured to send the current-item weight to a retail transaction system for calculating a current-item price.

16. The weighing system of any one of the preceding claims, additionally comprising a display device configured to display the current-item weight, and optionally a calculated current-item price.

17. The weighing system of any one of claims 8 to 16, wherein the current gross weight is registered by the weighing system at said second time in accordance with one of a stability rule and a duration rule.

18. A shopping cart comprising the weighing system of any one of claims 1 to 17.

19. A checkout station comprising the weighing system of any one of claims 1 to 17.

20. A method of operating a weighing system that comprises a weighing platform characterized by a weighing-platform weight range corresponding to a first level of precision, the weighing-platform weight range extending from a zero weightvalue to a weighing-platform maximum value, the method comprising: a. opening a virtual scale that uses the weighing platform and is characterized by a virtual-scale weight range corresponding to a second level of precision, the virtual-scale weight range being smaller than the weightplatform weight range, wherein the opening includes setting, at a first time, a virtual zero-weight value for the virtual-scale weight range to be equal to a current gross weight registered by the weighing system; and b. operating the virtual scale to determine a current-item weight, the operating including calculating, at a second time, a current-item weight for a current item added to the weighing platform after the first time, by subtracting the virtual zero-weight value for the virtual-scale weight range from a current gross weight registered by the weighing system.

21. A shopping cart comprising: a. a base portion comprising a plurality of wheels supporting the base portion, and one or more product-receiving units for receiving products therein or thereon;b. a weighing platform comprising one or more load cells, the weighing platform disposed and configured to register a weight of at least one of the one or more product-receiving units; and c. a controller comprising one or more processors and a non-transient storage device having stored thereupon program instructions, wherein said program instructions, when executed by the one or more processors, cause the one or more processors to: i. monitor weight measurement data registered by the weighing system; ii. analyze the weight measurement data to detect noise having a mechanical cause; and iii. creating an alert status in response to the detection.

22. The shopping cart of claim 21, wherein the detecting includes detecting that the noise meets at least one of an amplitude criterion and a pattern criterion.

23. The shopping cart of either one of claims 21 or 22, wherein the mechanical cause includes a rolling movement of the shopping cart.

24. The shopping cart of either one of claims 21 or 22, wherein the mechanical cause includes a physical interaction between a person and the shopping cart.

25. The shopping cart of any one of claims 21 to 24, wherein creating the alert status includes suspending a function of the weighing platform and / or of the controller, and said program instructions, when executed by the one or more processors, additionally cause the one or more processors to cancel said suspension upon detection of a reduction in the amplitude of said noise below the amplitude criterion or of a change in the noise to no longer meet the pattern criterion.

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