Method of reading an optically readable security element

Abstract

There is provided a method of reading an optically readable security element 20 using an image capturing device 10. The method comprises, by the image capturing device, reading the optically readable

Description

TECHNICAL FIELD The present disclosure relates to a method of reading an optically readable security element using an image capturing device, an image capturing device for reading an optically readable security element and a related system. BACKGROUND Security elements or tags are used to label objects in order to provide greater security in respect thereof. However, if an identity provided by a security element used to label an object can be replicated or reproduced, the security of the object is compromised. For example, a counterfeit product may appear genuine if labelled with a reproduction of a security element encoding an identity associated with a genuine version of the product. Hence, there is a desire to improve the security provided by security elements or tags. SUMMARY It is one aim of the present disclosure, amongst others, to provide a method of reading an optically readable security element which at least partially obviates or mitigates at least some of the disadvantages of the prior art, whether identified herein or elsewhere, or to provide an alternative approach. For instance, it is an aim of embodiments of the invention to provide a method of reading an optically readable security element using an image capturing device that improves the security provided in relation to an object. According to the present invention there is provided a method of reading an optically readable security element using an image capturing device, an image capturing device for reading an optically readable security element and a related system, as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims and the description that follows. According to a first aspect, there is provided a method of reading an optically readable security element using an image capturing device. The method comprises, by the image capturing device, reading the optically readable security element, optically determining a physical characteristic proximal to the optically readable security element, the determining being distinct from the reading, comparing the determined physical characteristic to an expected physical characteristic and calculating a correspondence between the determined physical characteristic and the expected physical characteristic. The method may further comprise extracting an identity from the optically readable security element and retrieving the expected physical characteristic based on the identity. Calculating the correspondence may comprise verifying the correspondence only if the determined physical characteristic matches the expected physical characteristic. The method may further comprise authenticating the optically readable security element only if the correspondence is verified. The method may further comprise computing a confidence measure that the determined physical characteristic matches the expected physical characteristic, wherein verifying the correspondence is based on the confidence measure. The method may further comprise optically determining a second physical characteristic proximal to the optically readable security element, comparing the determined second physical characteristic to an expected second physical characteristic, computing a second confidence measure that the determined second physical characteristic matches the expected second physical characteristic, verifying, based on the second confidence measure, the second correspondence only if the determined second physical characteristic matches the expected second physical characteristic, and authenticating the optically readable security element only if the second correspondence is verified. The method may further comprise transmitting an output signal in the event that the correspondence is not verified, wherein the output signal is an alert signal indicative of an inauthentic optically readable security element. The method may further comprise disabling the optically readable security element in response to the alert signal. The physical characteristic is a property of the optically readable security element. The physical characteristic may be at least one of: resolution, colouration, printing type, physical condition and material. The physical characteristic is determined using fingerprint region of interest, ROI, segmentation. The optically readable security element may comprise one or more optical emitters arranged to be read via emission radiation emitted from the one or more optical emitters. The optically readable security element may comprise one or more optical emitters arranged to be excited by excitation radiation, optionally emitted from the image capturing device. According to a second aspect, there is provided an image capturing device for reading an optically readable security element. The image capturing device comprises a reader configured to read the optically readable security element and a processor. The processor is configured to optically determine a physical characteristic proximal to the optically readable security element, wherein the determining is distinct from the reading, compare the determined physical characteristic to an expected physical characteristic, and calculate a correspondence between the determined physical characteristic and the expected physical characteristic. According to a third aspect, there is provided a system comprising an optically readable security element, and a data store. The data store is configured to store a calculated correspondence between an optically determinable physical characteristic of the optically readable security element and expected physical characteristic of the optically readable security element. BRIEF DESCRIPTION OF DRAWINGS For a better understanding of the invention, and to show how embodiments of the same may be brought into effect, reference will be made, by way of example only, to the accompanying Figures, in which: Figure 1 shows a method of reading an optically readable security element using an image capturing device; Figure 2 shows an image capturing device reading an optically readable security element that is attached to an object; Figure 3 shows components of the image capturing device of Figure 2; and Figure 4 shows a system comprising the optically readable security element of Figure 1 and a data storage. DETAILED DESCRIPTION Figure 1 shows a method of reading an optically readable security element using an image capturing device. The method of Figure 1 is best understood in conjunction with Figure 2, which shows an image capturing device 10 and an optically readable security element 20 attached to an object 30. The optically readable security element 20 shown in Figure 2 may comprise a hologram, bar code, QR code or similar, encoding an identity labelling the object 30. In the case of the optically readable security element 20 comprising a hologram, bar code, QR code or similar, such engineered components may be programmable, encoded with, or generally comprise information. For example, the engineered components may, advantageously, comprise information about the object 30 or information relating to the identity. Preferably, the optically readable security element 20 comprises a unique (e.g., randomised) component (e.g., a random deterministic feature), encoding the identity. For example, the optically readable security element 20 may comprise an engineered component and a randomised component, wherein the engineered component is programmed or otherwise encoded with information about the object 30 and the randomised component encodes the identity. The randomised component encoding the identity, compared with the engineered component encoding the identity, advantageously, engenders a more robust barrier to fraudulent reading of the optically readable security element 20. More preferably, the optically readable security element 20 comprises at least one optical emitter arranged to be read via emission radiation emitted therefrom. Relatedly, the at least one optical emitter may be arranged to be excited by excitation radiation. The one or more emitters may serve as the component that provides or serves as the unique identity. Advantageously, the optically readable security element 20 being read via emission emitted therefrom provides a more robust barrier to fraudulent reading, more readily preventing spoofing or copying by, for instance, simply replicating (e.g., by printing) a bar code, QR code or similar. This advantage is particularly prominent when one or more (e.g., hundreds, thousands, millions or more) of emitters are distributed randomly. This effect may be achieved using quantum dots, flakes of 2D materials, (e.g., small) molecules, atomic defects or vacancies, plasmonic structures or similar. In one example, an engineered component comprising encoded information may be located proximal to (e.g., adjacent to) a component that encodes the identity. This location may conveniently allow for easy reading of both components in sequence or parallel. For example, both components may be in, and so readable by, a same field of view 40 of the (e.g., sensor of the) image capturing device 10. The image capturing device 10 shown in Figure 2 may be a terminal device, such as a smartphone. The image capturing device 10 may be configured to emit excitation radiation to excite the at least one optical emitter (e.g., from an electromagnetic radiation source, such as a flash or LED). By being configured to emit excitation radiation, the image capturing device 10, advantageously, facilitates the aforementioned robust security. Further, emitting the excitation radiation from the image capturing device 10, advantageously, allows convenient control of excitation of the at least one optical emitter. A shown in Figure 1, the method comprises reading S1 the optically readable security element 20. Reading may be performed using sensors (not shown), such as image or video sensors (e.g., those typically included in image capturing devices, such as a camera). Reading S1 is performed in order to extract the identity encoded in the optically readable security element 20. The method comprises optically determining S2 a physical characteristic proximal to (e.g., in the same field of view 40 as) the optically readable security element 20. The determining S2 is distinct from the reading S1. In other words, determining S2 the physical characteristic is not necessarily related to any extracting of an identity provided by (e.g., encoded in) the optically readable security element 20 - they are different actions. Advantageously, determining S2 the physical characteristic facilitates authentication of the optically readable security element 20, providing an extra layer of security over determining the identity, as described in more detail below. The physical characteristic being proximal to the optically readable security element 20 means that the physical characteristic may be a physical characteristic of an area of the engineered component or the randomised component. The physical characteristic may also be a physical characteristic of an area immediately surrounding the optically readable security element 20 (e.g., an adhesion layer, backing layer, surrounding support or frame layer used to attach or support the optically readable security element 20 with respect to the object 30). The physical characteristic may be one or more of a resolution, a colouration (e.g., hue, shading, patternation, moire), a printing type, a physical condition and a material. The physical characteristic is generally related to inherent physical properties of the optically readable security element 20 and / or parameters associated with the manufacturing of the optically readable security element 20. For instance, the engineered component may comprise a specific paper with a characteristic texture and / or density or may comprise a particular ink or pigment, resulting a characteristic colouration. The physical characteristic is determined using fingerprint region of interest, ROI, segmentation. ROI segmentation involves, for example, identifying a region in the optically readable security element 20 and, for instance, binarising an intensity map of the region to produce a key. The method comprises comparing S3 the determined physical characteristic to an expected physical characteristic. For instance, returning to the above example of the engineered component comprising a specific paper with a characteristic texture and / or density, the density of the engineered component may be determined and compared with an expected density (e.g., expected grams per square centimetre). The method comprises calculating S4 a correspondence between the determined physical characteristic and the expected physical characteristic. Calculating S4 the correspondence may mean initial setting of the correspondence. Typically, calculating S4 the correspondence means checking an established correspondence. In other words, it is calculated how closely the determined physical characteristic corresponds to the expected physical characteristic. For instance, the method may further comprise computing a confidence measure that the determined physical characteristic matches the expected physical characteristic (e.g., a percentage confidence). Verifying the correspondence may then be based on the confidence measure. For example, the correspondence may be verified only if the confidence measure is greater than 95%. In more detail, computing the confidence measure may comprise normalising the physical characteristic and the expected physical characteristic (e.g., each with respect to a maximum value of a primary colour channel in the case that the physical characteristic is colouration) and determining a standard deviation based on the normalised physical characteristic and the expected physical characteristic. Advantageously, use of a confidence measure reduces the inconvenience that may be caused by false negatives while maintaining security. The expected physical characteristic may be the same for optically readable security element 20 regardless of the identity. However, each of groups of optically readable security elements 20 have different expected physical characteristics, which, advantageously, reduces the effect of a security breach to a single optically readable security element 20. In the latter case, the method may further comprise extracting an identity from the optically readable security element 20 and retrieving the expected physical characteristic based on the identity. Extracting an identity from the optically readable security element 20 may be performed as part of the reading S1. In other words, using the identity, the image capturing device 10 may look up the expected physical characteristic for comparison with the determined physical characteristic (i.e., the correspondence). The expected physical characteristic may be retrieved from a data store. The data store may be part of the image capturing device 10 or the data store may be an external apparatus in communication with the image capturing device 10. The data store being an external apparatus, advantageously, engenders a lightweight and compact image capturing device 10. Alternatively, the expected physical characteristic may be encoded, for example, in the engineered component of the optically readable security element 20, and the expected physical characteristic may be retrieved as part of the reading S1, advantageously, avoiding the expense that may be associated with the use of a data store. The method may further comprise authenticating the optically readable security element only if the correspondence is verified. In other words, once the determined physical characteristic is verified as corresponding to the expected physical characteristic, the optically readable security element 20 may be flagged as authentic. That is, it may be flagged that the optically readable security element 20 is genuine based on the correspondence. Advantageously, a user (e.g., someone purchasing the object 30 to which the optically readable security element 20 is attached) can not only be assured that the object is genuine but, relatedly, that the optically readable security element 20 is genuine, thereby providing an extra layer of security. In other words, security is provided by dual authentication of: (i) the object, by extracting an identity from the optically readable security element 20, and (ii) the optically readable security element 20 itself, by calculating a correspondence between the determined physical characteristic and the expected physical characteristic. The method may further comprise optically determining a second physical characteristic proximal to the optically readable security element 20, comparing the determined second physical characteristic to an expected second physical characteristic, computing a second confidence measure that the determined second physical characteristic matches the expected second physical characteristic, verifying, based on the second confidence measure, the second correspondence only if the determined second physical characteristic matches the expected second physical characteristic, and authenticating the optically readable security element 20 only if the second correspondence is verified. In other words, more than one physical characteristic may be used to authenticate the optically readable security element 20. A confidence level for the second physical characteristic may be the same or different to the confidence level for the first physical characteristic. For instance, returning to the above example of the engineered component comprising a specific paper with a characteristic texture and / or density, if the texture and the density are used as first and second physical characteristics, respectively, a confidence level for the texture may be different than a confidence level for the density. Advantageously, the reliability of measurements of different physical characteristics may be accounted for by having different confidence levels for different physical characteristics, increasing the security provided compared with only using one physical characteristic while still avoiding the inconvenience associated with inaccurate determination of the physical characteristics. The method may further comprise transmitting an output signal in the event that the correspondence is not verified. The output signal may be transmitted internally (e.g., to a component of the image capturing device 10) or externally (e.g., to an external device). The output signal is, advantageously, an alert signal indicative of an inauthentic optically readable security element 20. The output signal may be used to register the optically readable security element 20 as having been targeted in a counterfeiting attempt so that, advantageously, steps can be taken to inhibit counterfeit reproduction of the optically readable security element 20 (e.g., changing manufacturing methods and / or materials). The method may further comprise disabling the optically readable security element 20 in response to the alert signal. By disabling the optically readable security element 20, the optically readable security element 20 may be rendered no longer readable. Figure 3 shows the image capturing device 10 of Figure 2 in more detail. The reading S1 of the optically readable security element 20 is performed by a reader 11, which could include or be a sensor as discussed above. The optically determining S2, comparing S3 and calculating S4 is performed by a processor 12. The processor 12 may be configured to optically determine the physical characteristic, compare the physical characteristic with an expected characteristic and calculate the correspondence locally (i.e., at the image capturing device 10) or externally (e.g., at a server). The processor 12 may be dedicated hardware or existing hardware specifically configured to optically determine the physical characteristic, compare the physical characteristic with an expected characteristic and calculate the correspondence. Figure 4 shows a system comprising the optically readable security element 20, the object 30 and the data store 50, as respectively described above. In Figure 4, the data store 50 is shown as an external device. However, as mentioned, alternatively, the data store 50 may be part of the image capturing device 10. In summary, the present disclosure has described a method, a device and a system that result improved security of an object by enabling authentication of an optically readable security element 20 used to label the object in addition to using an identity encoded in the optically readable security element 20 to check the authenticity of the object. Although preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims and as described above. The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each aspect or exemplary embodiment of the invention, as set out herein are also applicable to all other aspects or exemplary embodiments of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each aspect or exemplary embodiment of the invention as interchangeable and combinable between different aspects and exemplary embodiments.

Claims

1. A method of reading an optically readable security element using an image capturing device, the method comprising, by the image capturing device:reading the optically readable security element to extract an identity from the optically readable security element;optically determining a physical characteristic using fingerprint region of interest, ROI, segmentation, wherein the physical characteristic is an inherent physical property of the optically readable security element and / or a parameter associated with the manufacturing of the optically readable security element, wherein the determining is distinct from the reading;comparing the determined physical characteristic to an expected physical characteristic; andcalculating a correspondence between the determined physical characteristic and the expected physical characteristic.

2. The method of claim 1, further comprising:extracting an identity from the optically readable security element; andretrieving the expected physical characteristic based on the identity.

3. The method of claim 1 or 2, wherein calculating the correspondence comprises:verifying the correspondence only if the determined physical characteristic matches the expected physical characteristic.

4. The method of claim 3, further comprising:authenticating the optically readable security element only if the correspondence is verified.

5. The method of claim 4, further comprising:computing a confidence measure that the determined physical characteristic matches the expected physical characteristic,wherein verifying the correspondence is based on the confidence measure.

6. The method of claim 5, further comprising:optically determining a second physical characteristic of the optically readable security element;comparing the determined second physical characteristic to an expected second physical characteristic;computing a second confidence measure that the determined second physical characteristic matches the expected second physical characteristic;verifying, based on the second confidence measure, the second correspondence only if the determined second physical characteristic matches the expected second physical characteristic; andauthenticating the optically readable security element only if the second correspondence is verified.

7. The method of any one of claims 3 to 6, further comprising:transmitting an output signal in the event that the correspondence is not verified,wherein the output signal is an alert signal indicative of an inauthentic optically readable security element.

8. The method of any preceding claim, wherein the physical characteristic is at least one of: resolution, colouration, printing type, physical condition and material.

9. The method of any preceding claim, wherein the optically readable security element comprises one or more optical emitters arranged to be read via emission radiation emitted from the one or more optical emitters.

10. The method according to any preceding claim, wherein the optically readable security element comprises one or more optical emitters arranged to be excited by excitation radiation, optionally emitted from the image capturing device.5 11. An image capturing device for reading an optically readable security element, theimage capturing device comprising:a reader configured to read the optically readable security element to extract an identity from the optically readable security element; anda processor configured to:10 optically determine a physical characteristic using fingerprint region ofinterest, ROI, segmentation, wherein the physical characteristic is an inherent physical property of the optically readable security element and / or a parameter associated with the manufacturing of the optically readable security element, wherein the determining is distinct from the reading;15 compare the determined physical characteristic to an expected physicalcharacteristic; andcalculate a correspondence between the determined physical characteristic and the expected physical characteristic.

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