System and method of verifying display of visual information

Abstract

A method of verifying display of primary visual information on a screen of an electronic visual display device. Primary visual information is combined with visual verification information to create combined primary and verification visual information in a computer-usable format. The combined primary and verification visual information is rendered on the screen of the visual display device. The screen is monitored using an optical detector to detect display of the visual verification information on the screen thereby verifying display of the primary visual information.

Description

[0001] System and Method of Verifying Display of Visual Information

[0002] Field of the Invention

[0003] This invention relates to the display of visual information by an electronic visual display device, and more particularly to verifying display of visual information by the electronic visual display device.

[0004] Background to the Invention

[0005] In the field of advertising and promotion it is well known for organisations to create promotional videos or the like for display by electronic visual display devices. These videos may be displayed at a large number of locations and it can be difficult for the organisations, or for a service provider whose responsibility it is to organise the display of the videos, to verify that all of the scheduled plays of the video have been made and / or that they have been made with acceptable levels of quality.

[0006] One problem in this regard is that, even if the video file is sent to the display device, the display device may have its screen switch off, or may be tuned to the wrong channel or switched to the wrong input, in which case the video is not actually displayed.

[0007] Another problem with some existing verification systems is that they require specialized media players, which is inconvenient and costly. A further problem is the variation in display characteristics (e.g. colour definition, colour tone, brightness, contrast and so on), which can vary from model to model or over time (e.g. as a result of degradation or adjustment of settings) and which can result in failure of the verification system.

[0008] A further problem is that depending on the resolution, speed or rendering requirements of particular visual content to be displayed, some media players may have difficulty rendering the video or presentation in an acceptably smooth manner, e.g. without perceptible buffering or jitter, which adversely affects the quality of the rendered video or presentation. This problem may result from multiple factors including but not limited to the performance of the media player, its age, the resources available on it and the software that it is running.

[0009] Yet another problem is that some media players may render the video or presentation with unsatisfactory visual characteristics, e.g. in terms of illuminance, luminance, brightness and / or colour, which also adversely affects the quality of the rendered video or presentation.

[0010] A still further problem is assessing how many people view any given video each time it is displayed. It would be desirable to mitigate one or more of the problems outlined above.

[0011] Summary of the Invention

[0012] From a first aspect the invention provides a method of verifying display of primary visual information on a screen of at least one electronic visual display device, the method comprising: combining said primary visual information with visual verification information to create combined primary and verification visual information in a computer-usable format; causing said combined primary and verification visual information to be rendered on the screen of said at least one visual display device; monitoring said screen using at least one optical detector to detect display of said visual verification information on said screen.

[0013] Preferably, said combining involves creating a computer file containing data representing said combined primary and verification visual information.

[0014] Preferably, said causing involves causing said combined primary and verification visual information to be rendered on the screen of said at least one visual display device by at least one media player, and wherein said combining involves creating a computer file containing data representing said combined primary and verification visual information, said computer file being of a format that is suitable for playing by said at least one media player.

[0015] Preferably, said combining involves obtaining said primary visual information in a computer-usable format, rendering said primary visual information, combining said visual verification information with said primary visual information during said rendering, preferably by overlaying said primary visual information with said visual verification information.

[0016] Preferably, said rendering involves rendering said primary visual information using a visual media editor.

[0017] Preferably, said combining said visual verification information with said primary visual information during said rendering is performed by or using a visual media editor.

[0018] Preferably, said creating combined primary and verification visual information in a computer-usable format involves recording the combined primary and verification visual information during said rendering.

[0019] Preferably, said combining is performed at or by a first computing system, preferably being a cloud computing system, said at least one visual display device being located at at least one site, and wherein typically one or more media player is located at said at least one site for rendering said combined primary and verification visual information on the screen, said method including communicating said combined primary and verification visual information in said computer-usable format to said at least one site, typically to said one or more media player, via a telecommunications network.

[0020] Typically the method includes displaying said visual verification information at at least one verification location on a display area of said screen, and monitoring said at least one location using said at least one optical detector, and wherein, preferably, said at least one verification location is located at a peripheral part of said display area, preferably at a corner or side of said display area.

[0021] Preferably, said primary visual information comprises a visual presentation, and wherein said combined primary and verification visual information comprises said visual presentation modified to include said visual verification information.

[0022] Preferably, said visual verification information comprises a sequence of visual elements for displaying on the screen and that are detectable by said at least one optical detector, and wherein said method preferably includes combining said visual verification information with said primary visual information such that said visual elements are displayed one at a time according to the sequence.

[0023] Preferably, each visual element is set to, or otherwise configured to represent, any one of a plurality of colours and / or a plurality of tones, and / or optionally a plurality of patterns.

[0024] Preferably, said sequence of visual elements comprises at least one visual element, preferably a plurality of said visual elements, configured to provide an identifier, and wherein said identifier identifies, preferably uniquely identifies, said combined primary and verification visual information.

[0025] Optionally, said sequence of visual elements comprises an initial part, said initial part comprising one or more of said visual elements configured to provide synchronisation information and / or one or more of said visual elements configured to provide ancillary information, wherein said ancillary information may comprise the duration for which each visual element will be displayed.

[0026] Typically said initial part precedes said identifier and wherein said ancillary information may comprise any one or more of: the number of visual elements in the identifier; the duration for which each visual element of the identifier will be displayed; the duration for which the identifier will be displayed.

[0027] Optionally, said sequence of visual elements comprises an end part, said end part comprising one or more of said visual elements configured to provide synchronisation information and / or one or more of said visual elements configured to provide error checking information.

[0028] In preferred embodiments, said sequence of visual elements comprises a sequence of visual elements configured to provide calibration information. Said calibration information preferably comprises at least one visual element representing each of the different variations that the visual elements can take arranged in a known sequence, or a known sequence of visual elements set to a respective different colour and / or tone to allow calibration of the screen. Preferably, said calibration information comprises at least one visual element representing each of the different colours and / or tones and / or patterns that the visual elements can take arranged in a known sequence, or a known sequence of visual elements set to a respective different colour and / or tone to allow calibration of the screen.

[0029] Optionally, said calibration information comprises or is included in said initial part.

[0030] Preferably, said visual verification information comprises at least one visual element configured to provide an identifier, and wherein said identifier identifies, preferably uniquely identifies, said combined primary and verification visual information, and wherein, optionally, said identifier comprises a visual element in the form of a visual code, for example a QR code.

[0031] Typically, the method further includes analysing output signals generated by the optical detector in order to detect the visual verification information.

[0032] In preferred embodiments, said analysing involves recognising colours and / or tones and / or patterns and / or images represented by the information contained in the output signal in order to detect the visual verification information.

[0033] Preferably, said analysing involves detecting the visual verification information by detecting each visual element.

[0034] Preferably, said analysing involves detecting said identifier.

[0035] Preferably, said analysing involves detecting said initial part and synchronising detection of the visual verification using said synchronisation information and / or extracting said ancillary information.

[0036] Preferably, said analysing involves detecting said end part and synchronising detection of the visual verification using said synchronisation information and / or extracting said error checking information and performing an error checking process on said visual verification information using said error checking information.

[0037] Preferably, said analysing involves detecting said calibration information and using said calibration information to calibrate detection of said visual verification information.

[0038] Typically the method includes verifying display of said primary visual information by determining that said visual verification information is detected on said screen by said at least one optical detector.

[0039] The method may further include associating ancillary information with the detected identifier, wherein the ancillary information may comprise any one or more of: the time and / or date at which the identifier is detected; the duration for which the respective visual presentation was played; the geographical location at which the identifier is detected; and a unique ID of a reader that detected the identifier. Preferably, the method includes communicating said identifier, preferably with said associated ancillary information, to said first computing system, and, preferably, verifying at said first computing system the display of said primary visual information using said identifier and, optionally, said associated ancillary information.

[0040] Preferably, the method includes determining one or more characteristics, for example relating to quality, of how said visual information is displayed by the respective display device using said calibration information, preferably using multiple instances of said calibration information detected over time, optionally based on variations in said calibration information over time.

[0041] The preferred method further includes communicating said calibration information to said first computing system and, preferably, performing said determining of one or more characteristics at said first computing system.

[0042] In preferred embodiments, the method includes measuring at least one visual characteristic of how the visual verification information is rendered, comparing the, or each, measured visual characteristic with a respective corresponding desired visual characteristic, and providing an assessment of the quality of the rendered primary visual information based on the comparison, wherein, optionally, said at least one visual characteristic comprises any one or more of: illuminance, luminance, brightness and / or colour, in particular how one or more colours are rendered.

[0043] In preferred embodiments, the method includes measuring one or more visual characteristics of how the visual verification information (and therefore the presentation comprising the primary visual information) is rendered, preferably in respect of any one or more of: illuminance, luminance, brightness and / or colour (e.g. how colours are rendered). The method may involve using the measurement(s) to provide an assessment or indication of the quality of the rendered visual presentation and / or to assess the performance of the display device. The method may involve, if the measured visual characteristic(s) exceed an upper threshold, or fall below a lower threshold, or vary by more than a threshold amount over time, or exhibits a trend such as increasing, decreasing or otherwise changing over time, providing an indication of unsatisfactory rendering quality and / or of unsatisfactory performance of the display device, and / or may involve generating one or more corresponding report or other output(s) for the user. The assessment(s) may involve comparing the measured visual characteristic(s) with a respective corresponding desired, or reference, visual characteristic(s) and / or detecting variations in the measured visual characteristic(s) over time, or otherwise monitoring the measured visual characteristic(s).

[0044] In preferred embodiments, the method includes determining a duration for which at least one visual element of the visual verification information is displayed, and comparing the determined duration with an expected duration, and preferably providing an assessment of the quality of the rendered primary visual information based on the comparison and / or providing a report indicating the results of the comparison or otherwise being based on the comparison. Preferably, said comparing involves determining if the determined duration differs from the expected duration, preferably by more than a threshold amount, and, preferably, upon determining that the determined duration differs from the expected duration, preferably by more than the threshold amount, providing an indication that the rendering of the visual verification information and / or of the primary visual information is unsatisfactory. The method may include, upon determining that the determined duration exceeds the expected duration, preferably by more than the threshold amount, providing an indication that buffering or jitter has adversely affected the rendering. Said determining a duration for which at least one visual element of the visual verification information is displayed may involve sampling the visual verification at a sampling rate and determining the number of samples taken for the, or each, visual element.

[0045] In preferred embodiments, the method involves detecting, conveniently using one or more wireless receiver, wirelessly enabled electronic devices in the vicinity of the display device during the, or each, rendering of the primary visual information, and to record the number of detected devices in association with the primary visual information and / or with the respective rendering of the primary visual information.

[0046] From a second aspect the invention provides a system for verifying display of primary visual information on a screen of at least one electronic visual display device, the system comprising: means for combining said primary visual information with visual verification information to create combined primary and verification visual information in a computer-usable format; means for causing said combined primary and verification visual information to be rendered on the screen of said at least one visual display device; and means for monitoring said screen using at least one optical detector to detect display of said visual verification information on said screen.

[0047] Said at least one optical detector may comprise one or more photodetector or other optoelectronic device. Said at least one optical detector may be a colour sensor, a greyscale sensor, or a binary (e.g. black and white) sensor. Said at least one optical detector may comprise an image sensor or a digital camera.

[0048] The system may comprise means for performing any one or more of the above-identified method steps of the first aspect of the invention.

[0049] From a third aspect the invention provides a method of verifying display of primary visual information on a screen of at least one electronic visual display device, the method comprising: causing said primary visual information and verification visual information to be rendered together on the screen of said at least one visual display device; monitoring said screen using at least one optical detector to detect display of said visual verification information on said screen; including providing calibration information in said visual verification information. The method of the third aspect may include any one or more of the above-identified method steps of the first aspect of the invention. A fourth aspect of the invention provides a system including means for performing the method of the third aspect of the invention.

[0050] From a fifth aspect the invention provides a method of verifying display of primary visual information on a screen of at least one electronic visual display device, the method comprising: causing said primary visual information and verification visual information to be rendered together on the screen of said at least one visual display device; monitoring said screen using at least one optical detector to detect display of said visual verification information on said screen; measuring at least one visual characteristic of how the visual verification information is rendered; comparing the, or each, measured visual characteristic with a respective corresponding desired visual characteristic, and providing an assessment of the quality of the rendered primary visual information based on the comparison, wherein, optionally, said at least one visual characteristic comprises any one or more of: illuminance, luminance, brightness and / or colour, in particular how one or more colours are rendered. The method of the fifth aspect may include any one or more of the above-identified method steps of the first aspect of the invention.

[0051] A sixth aspect of the invention provides a system including means for performing the method of the fifth aspect of the invention.

[0052] From a seventh aspect the invention provides a method of verifying display of primary visual information on a screen of at least one electronic visual display device, the method comprising: causing said primary visual information and verification visual information to be rendered together on the screen of said at least one visual display device; monitoring said screen using at least one optical detector to detect display of said visual verification information on said screen; measuring one or more visual characteristics of how the visual verification information (and therefore the presentation) is rendered, preferably in respect of any one or more of: illuminance, luminance, brightness and / or colour (e.g. how colours are rendered). The method may involve using the measurement(s) to provide an assessment or indication of the quality of the rendered visual presentation and / or to assess the performance of the display device. The method may involve, if the measured visual characteristic(s) exceed an upper threshold, or fall below a lower threshold, or vary by more than a threshold amount over time, or exhibits a trend such as increasing, decreasing or otherwise changing over time, providing an indication of unsatisfactory rendering quality and / or of unsatisfactory performance of the display device, and / or may involve generating one or more corresponding report or other output(s) for the user. The assessment(s) may involve comparing the measured visual characteristic(s) with a respective corresponding desired, or reference, visual characteristic(s) and / or detecting variations in the measured visual characteristic(s) over time, or otherwise monitoring the measured visual characteristic(s). The method of the seventh aspect may include any one or more of the above-identified method steps of the first aspect of the invention. An eighth aspect of the invention provides a system including means for performing the method of the seventh aspect of the invention.

[0053] From a ninth aspect the invention provides a method of verifying display of primary visual information on a screen of at least one electronic visual display device, the method comprising: causing said primary visual information and verification visual information to be rendered together on the screen of said at least one visual display device; monitoring said screen using at least one optical detector to detect display of said visual verification information on said screen; determining a duration for which at least one visual element of the visual verification information is displayed; and comparing the determined duration with an expected duration, and preferably providing an assessment of the quality of the rendered primary visual information based on the comparison and / or providing a report indicating the results of the comparison or otherwise being based on the comparison. Preferably, said comparing involves determining if the determined duration differs from the expected duration, preferably by more than a threshold amount, and, preferably, upon determining that the determined duration differs from the expected duration, preferably by more than the threshold amount, providing an indication that the rendering of the visual verification information and / or of the primary visual information is unsatisfactory. The method may include, upon determining that the determined duration exceeds the expected duration, preferably by more than the threshold amount, providing an indication that buffering or jitter has adversely affected the rendering. Said determining a duration for which at least one visual element of the visual verification information is displayed may involve sampling the visual verification at a sampling rate and determining the number of samples taken for the, or each, visual element. The method of the ninth aspect may include any one or more of the above-identified method steps of the first aspect of the invention.

[0054] A tenth aspect of the invention provides a system including means for performing the method of the ninth aspect of the invention.

[0055] From an eleventh aspect the invention provides a method of verifying display of primary visual information on a screen of at least one electronic visual display device, the method comprising: causing said primary visual information and verification visual information to be rendered together on the screen of said at least one visual display device; monitoring said screen using at least one optical detector to detect display of said visual verification information on said screen; detecting, conveniently using one or more wireless receiver, wirelessly enabled electronic devices in the vicinity of the display device during the, or each, rendering of the primary visual information, and recording the number of detected devices in association with the primary visual information and / or with the respective rendering of the primary visual information.

[0056] A twelfth aspect of the invention provides a system including means for performing the method of the eleventh aspect of the invention. Further advantageous aspects of the invention will be apparent to those ordinarily skilled in the art upon review of the following description of a specific embodiment and with reference to the accompanying drawings.

[0057] Brief Description of the Drawings

[0058] An embodiment of the invention is now described by way of example and with reference to the accompanying drawings in which:

[0059] Figure 1 is a schematic diagram of a system for verifying display of visual information on a screen of an electronic visual display device;

[0060] Figure 2 is a schematic perspective view of part of the screen;

[0061] Figure 3 is an end view of part of the screen;

[0062] Figure 4A is a plan view of an optical detection assembly suitable for use in embodiments of the invention;

[0063] Figure 4B is a plan view of an alternative embodiment of the optical detection assembly;

[0064] Figure 5A is a schematic illustration of visual verification information suitable for use with embodiments of the invention;

[0065] Figure 5B is a schematic illustration of calibration information that may be included in the visual verification information; and

[0066] Figure 6 is a table illustrating an exemplary assignment of colours to codes.

[0067] Detailed Description of the Drawings

[0068] Referring now to the drawings, there is shown, generally indicated as 10, a system for verifying display of visual information on a screen of an electronic visual display device, the system embodying an aspect of the present invention.

[0069] The system 10 comprises at least one electronic visual display device 12 having a display screen 14, which may also be referred to as a display or screen. In the illustrated embodiment only one display device 12 is shown, although in typical embodiments the system 10 comprises a plurality of display devices 12 (e.g. a plurality of display devices 12 at the same site, or a respective one or more display device 12 at each of a plurality of sites, where each site may for example be a bar, restaurant, shop or other premises or venue). The display device 12 may be of any known type, for example a computer or other computing device, a computer monitor, a display monitor, a television, or a projector system. The display screen 14 may be of any known type, for example cathode ray tube, LED, OLED, LCD, plasma display panel, or other video display or projector screen. The display screen 14 is typically an integral part of the display device 12, but may be separate, e.g. in cases where the display device 12 comprises a projector and the display screen 14 comprises a screen onto which a video or other visual presentation is projected.

[0070] The system 10 includes means for monitoring the screen 14 to detect display of visual verification information on the screen 14. In preferred embodiments, to this end the system 10 includes at least one optical detector 30 for each screen 14. The, or each, optical detector 30 produces an output signal that is indicative of the optical information that it detects on the screen 14 during use. The optical detector 30 may comprise one or more optical sensor (preferably one or more colour sensor), typically incorporated into optical detection circuitry for producing the output signal. Each optical detector 30 is mounted on, or otherwise supported with respect to, the display device 12 and is arranged to monitor the screen 14. In particular, each optical detector 30 is positioned to monitor a specific location 32 on the display area 15 of the screen 14, which is referred to hereinafter as the verification location 32. The verification location 32 occupies only a portion of the display area 15 of the screen 14. The size of the verification location may vary depending on the size of the screen and / or the size of the screen pixels. Preferably, the verification location occupies less than 10% of the display area of the screen 14, more preferably less than 5% of the display area, and typically less than 1% of the display area. For example, the verification location may comprise an area corresponding to 1 pixel, up to 10 pixels, or 10s of pixels or 100s of pixels, as suits the application. In preferred embodiments, the verification location 32 is located at the periphery of the display area 15, for example at a corner (as illustrated) or along a side of the display area 15. The primary visual information may be displayed using the entire display area 15 or any other desired region of the display area 15. The, or each, verification location 32 occupies a portion of the display area 15 that is smaller than is used to display the primary visual information.

[0071] In typical embodiments, only one optical detector 30 is provided for each screen 14. However, optionally more than one detector 30 may be provided for each screen 14, in which case they may each monitor a respective separate verification location, or an overlapping verification location, or the same verification location as desired.

[0072] The system 10 comprises means for sending input signals to the electronic visual display device 12. In preferred embodiments, to this end the system 10 includes at least one media player 16 for playing digital media (in particular digital visual media, e.g. images, videos and / or animations) on the display device 12. The media player 16 may take any known form, comprising software and / or hardware as convenient. For example, the media player 16 may comprise a dedicated electronic device such as a digital media player, or may comprise media player software running on a computer. The media player 16 may be a stand-alone device (as illustrated) or may be integrated with the display device 12. The media player 16 may be connected to the display device 12 by any conventional means, for example a wired and / or wireless connection, which may be direct (as illustrated by connection 13) or across a telecommunications network 11 (which may for example comprise one or more computer network (e.g. a LAN, WAN and / or the internet) and / or a telephone network), and the media player 16 includes wired and / or wireless communication means (e.g. WiFi or Bluetooth) as required. Typically, the media player 16 comprises a microprocessor, microcontroller or other processor that is programmed or otherwise configured control the operation of the media player 15, including implementing the functionality described herein. The media player 16 typically includes a display driver (not shown) for sending signals to the display device 12 to cause the display device 12 to display corresponding video(s), visual media or other visual information carried by the signals. The media player 16 may be configured in any conventional manner to store data representing video(s), visual media or other visual information to be sent to the display device 12 and / or to receive such data received from a remote source via wired and / or wireless link, and may include wired and / or wireless communication means (e.g. WiFi or Bluetooth) and / or data storage means as required. The media player 16 may be configured to play media (e.g. video(s), visual media or other visual information) from its data storage means and / or to stream the media from the remote source.

[0073] In the illustrated embodiment, there is one media player 16 although in alternative embodiments there may be a plurality of media players 16. Each media player 16 may service a respective display device 12 or multiple display devices 12, as desired, and / or each display device 12 may be serviced by more than one media player 16.

[0074] The preferred system 10 comprises a central control system 20, conveniently implemented as a cloud computing platform or cloud server system or other server, which may comprise one or more computers, which may be distributed or co-located as is convenient, and which run computer program(s) for implementing the functionality described herein. The control server 20 may provide server functionality to the media player(s) 16, for example in the form of a hosted cloud server or a dedicated web server. Each media player 16 is in communication with the control server 20 across the telecommunications network 11 and the media player(s) 16 and control server 20 include corresponding wired and / or wireless communication means as required. Typically, each media player and display device are remote from the control system 20, i.e. not located at the same site.

[0075] In preferred embodiments, the system 10 comprises, or is capable of communication with, at least one client computing device 18. Each client device 18 is in communication with the control server 20 across the telecommunications network 11 . The control server 20 may provide server functionality to the client(s) 18, for example in the form of a hosted cloud server or a dedicated web server. It will be understood that the media player(s) 16, client(s) 18 and server 20 may communicate with each other, as applicable, using the same communications network, or a different communications network or different parts of the same communications network, all of which are represented by the telecommunications network 11 .

[0076] The media player 16 is configured to provide one or more input signal to the, or each, display device

[0077] 12 with which it is associated. The input signal carries data representing the primary visual information that it is desired to display on the screen 14. The primary visual information typically comprises any one or more of: text, image(s), animation(s), video(s) and / or any visual digital medium or visual digital media as desired, and may be provided in any suitable digital data format(s) or digital media format(s) as required. Audio data may also be included if desired. Typically, the primary visual information comprises an advertisement, promotional video or other single-medium or multimedia visual still or sequence. More generally, the primary visual information comprises a visual presentation, e.g. a video or animation, for displaying on one or more display device 12. Usually, the primary visual information is intended for display using the entire of the display area 15.

[0078] The input signal(s) also carries data representing visual verification information for displaying on the screen 14 simultaneously with the primary visual information. In preferred embodiments, the visual verification information is displayed, in use, at one or more verification location 32 on the screen 14. In embodiments where there is more than one verification location on the screen 14, respective verification information may be provided for display at each respective verification location. In preferred embodiments data representing the visual verification information and the primary visual information are contained in the same computer-usable file, in particular a computer file that can be played by the media player 16 such that the visual verification information and primary visual information are rendered on the screen. The computer file may conform with one or more digital file formats, in particular one or more file format for video and / or animation, but which may alternatively or in addition comprise one or more digital file format for image(s), text and / or any or any visual digital medium or visual digital media. For example, the computer file may be an MPEG file, an AVI file, a Windows Media Video file, a QuickTime file, a GIF file, a flash video file, a Lottie file and so on. In typical embodiments the computer file may be said to comprise a video file, in particular a digital video file, wherein the term video is intended to embrace any moving visual media or images including animation. The preferred arrangement is such that the visual verification information and the primary visual information are combined in the computer file such that, when the computer file is played by the media player 16, the visual verification information and the primary visual information are displayed together on the screen 14 as single visual presentation, and in particular such that the visual verification information is displayed at the or each verification location 32 during display of the primary visual information. The visual verification information is an integral part of the visual presentation and is not, for example, rendered as an overlay to the primary visual information or is not otherwise separate or separable from the primary visual information. In preferred embodiments, the visual verification information can uniquely identify the primary visual information into which it is incorporated. As such, display of the primary visual information on the display 14 can be detected by detecting display of the respective visual verification information.

[0079] In preferred embodiments, the computer file with the combined visual verification information and primary visual information is created at the control server 20. To this end, the control server 20 may include a visual media editor 21 , e.g. a video editor. The editor 21 may be of any conventional type, comprising computer hardware and / or software as applicable. Typically the editor 21 comprises one or more computer program running on a computer processor. The editor 21 is configured to, or is operable to, edit or otherwise modify a video or visual presentation, and to save a corresponding computer file containing the modified video or visual presentation. In preferred embodiments, the video editor 21 is configured to receive a computer file 23, typically a video file, that contains the primary visual information (PVI), and to create a computer file 27 that contains the primary visual information combined with the visual verification information (combined visual information (CVI)). The PVI file 23 and the CVI file 27 may conform to any suitable conventional digital format(s), in particular video and / or animation file formats, as outlined above. It is noted that the PVI file 23 and the CVI file 27 may conform to the same file format(s) or different file format(s). The CVI file 27 is created in a format(s) that is supported by the media player 16. The PVI file 23 may be provided in the same format(s) or other format(s) including format(s) not supported by the media player 16.

[0080] In typical embodiments, the PVI file 23 is provided to the control server 20 by the client 18 (or any one of the clients 18), typically via the communications network 11 . The control server 20 may store the, or each, PVI file 23 in any convenient data storage means (not shown). A user (not shown) may create all or part of the primary visual information using the client device 18, for example using suitable digital media software supported by the client device 18 and / or using digital media software service(s) provided by the server 20. The resulting primary visual information data is available to the control server 20. The control server 20 may create the primary visual information data or receive all or part of it from the client device 18 depending on the embodiment. The control server 20 incorporates the visual verification information data with the primary visual information data in the CVI file 27.

[0081] The visual verification information (VVI) may be provided in any convenient manner. For example, the VVI may be provided in a computer file 25 in a file format suitable for use by the video editor 21 . The VVI file 25 need not be a video file and may, for example, be a text file containing data representing the VVI. The VVI file 25 may be created by the video editor 21 , e.g. automatically generated or by a user via the video editor 21 . Alternatively, the VVI file 25 may be created by another computer program that may be provided at the control server 20, or provided elsewhere in which case it may be communicated to the server 20 via the communications network 11 . The control server 20 may store the, or each, VVI file 25 in any convenient data storage means (not shown). Alternatively, the visual verification information may be created by the video editor 21 as part of the process for creating the CVI file 27, e.g. created by a user using the video editor 21 when creating the CVI file 27. In preferred embodiments, a unique VVI is provided for each instance of the primary visual information such that playing of the primary visual information can be detected by detection of the respective VVI.

[0082] The visual verification information may be incorporated with the primary visual information and stored as the CVI file 27 by any convenient means. In preferred embodiments, the video editor 21 may render the primary visual information, overlay or otherwise add the visual verification information to the primary visual information during the rendering of the primary visual information, and record the rendered combination of the primary visual information and visual verification information in order to create the CVI file 27. The creation of the CVI file 27 may be performed automatically by the video editor 21 , for example using the respective PVI and VVI files 23, 25, or may be performed by a user of the video editor 21 . The creation of the CVI file 27 involves incorporating the visual verification information with the primary visual information such that when the CVI file 27 is played by the media player 16, the visual verification information is displayed at the or each verification location 32. For example, creating the CVI file 27 may involve rendering the primary visual information, overlaying or otherwise adding the visual verification information to the primary visual information during the render the primary visual information such that the visual verification information is located at the or each verification location 32, and recording the rendered combination of the primary visual information and visual verification information in order to create the CVI file 27.

[0083] The CVI file 27 is provided to the, or each, media player 16, typically via network 11 , for rendering via the display device 12. Advantageously, because the CVI file 27 conforms to a format supported by the media player 16, the media player 16 only needs to play the CVI file 27 in order to render, on the screen 14, the primary visual information and the visual verification information. As such there is no need for the media player 16 to separately receive, create or store the visual verification information, or to overlay the visual verification information on the primary visual information during rendering, or otherwise to be modified to support the verification process, thereby allowing standard or conventional media players 16 to be used.

[0084] The visual verification information may take any desired form. In particular, the visual verification information may comprise any visual information that may be displayed on the screen 14 and which can be detected by the optical detector 30. The visual verification information typically comprises or more visual elements, preferably a sequence of visual elements. For example, the visual verification information may comprise a colour and / or tone (e.g. binary (black or white), grayscale or RGB), a sequence of colours and / or tones (e.g. binary (black or white), grayscale or RGB), a code (e.g. an alphanumeric code or a QR code), an image or sequence of images, a character or sequence or characters, a pattern or a sequence of patterns, a symbol or a sequence of symbols. In preferred embodiments, the visual verification information comprises a plurality of visual elements that are, in use, displayed one at a time in sequence at the respective verification location 32. Alternatively, the visual verification information may comprise a single visual element, e.g. a QR code or other visual code element that is capable of uniquely identifying the respective visual presentation into which it is incorporated, or a sequence of multiple such code elements. In some embodiments, the visual verification information may comprise a mix of different types of visual element. For example, the visual verification information may comprise a visual code element, e.g. a QR code, as a unique identifier for the respective visual presentation and a sequence of colour(s) and / or tone(s) for use in calibrating the display device, as is described in more detail hereinafter. The arrangement may be such that the different types of visual element appear at the same visual verification location(s) or at different visual verification location(s). Advantageously, the visual verification information comprises visual element(s) of a type that can be detected by a simple optical detector such as a colour sensor, a greyscale sensor, or a binary (e.g. black and white) sensor. For example, in the case where the optical detector 30 comprises an RGB colour sensor, the visual verification information may comprise an RGB colour, or sequence of RGB colours and / or colour tones. Alternatively, in cases where the optical detector 30 comprises a digital camera, the visual verification information may comprise an image or sequence of images, or a visual code element, e.g. a QR code, or sequence of visual code elements. Typically, the visual verification information is displayed using the, or each, pixel that is allocated to the verification location 32.

[0085] Figure 5A illustrates an example of visual verification information suitable for use with preferred embodiments of the invention. The visual verification information comprises an identifier 60 comprising a sequence of visual elements 62. Preferably, the identifier 60 is a unique identifier that is capable of uniquely identifying the primary visual information (or CVI file 27) in which it is included, in which case the sequence of visual elements 62 may be a unique sequence of visual elements 62.

[0086] As illustrated in the example of Figure 5A, each visual element 62 is a colour and / or tone (e.g. binary (black or white), grayscale or RGB). As such, each visual element 62 is particularly suitable for rendering by one or more pixel of the screen 14, typically as a block (which may take any convenient shape, e.g. rectangular or circular) of the relevant colour and / or tone. Each visual element 62 may be any one of a plurality of different colour(s) and / or tone(s). In the example of Figure 5A, each visual element 62 may be any one of six different colours and tones, namely red (R), blue (B), yellow (Y), black (BK), white (W) or green (G), although in alternative embodiments there may be more or fewer colours and / or tones for each visual element to take. In other embodiments, each visual element 62 may be any one of a plurality of different variations of other visual element types such as symbols, characters, patterns, images and so on. In the embodiment of Figure 5A, the identifier 60 comprises 12 visual elements 62, although in alternative embodiments the identifier 60 may comprise more or fewer visual elements 62.

[0087] Preferably, each colour or tone (or other visual element type in other embodiments) is associated with a respective code, for example a respective numeral as is illustrated in Figure 6 or any other convenient code (typically comprising numeral(s) and / or letter(s)).

[0088] In preferred embodiments, the visual verification information includes an initial part 64, comprising one or more visual element 62, that precedes the identifier 60. The initial part 64 may comprise synchronisation information typically in the form of an indicator of the start of the identifier 60. The start indicator typically comprises a specific visual element 62 (e.g. a specific colour or tone or pattern) or a specific sequence of visual elements 62 that precede the sequence of visual elements 62 that make up the identifier 60 and which can be used to detect the start of the identifier 60 (e.g. such that the first visual element 62 of the identifier 60 occurs immediately after, or a known number of visual elements 62 after, the occurrence of the last visual element 62 of the start indicator). In the example of Figure 5A, the start indicator comprises a sequence of four blue visual elements 62, although any other uniquely identifiable sequence may be used as is convenient.

[0089] The initial part 64 may comprise one or more visual element 62 that carries ancillary information identifying one or more characteristic of the identifier 60, for example any one or more of: the number of visual elements 62 in the identifier 60; the duration for which each visual element 62 will be displayed; the duration for which the identifier 60 will be displayed; the number of times the identifier 60 will be repeated; the type of the visual elements 62. This information may be encoded in or otherwise provided by one or more visual elements 62, typically a sequence of visual elements 62, included in the initial part 64, typically preceding the start indicator.

[0090] In preferred embodiments, the visual verification information includes an end part 66, comprising one or more visual element 62, that succeeds the identifier 60. The end part 66 may comprise synchronisation information typically in the form of an indicator of the end of the respective instance of visual verification information. The end indicator typically comprises a specific visual element 62 (e.g. a specific colour or tone or pattern) or a specific sequence of visual elements 62 that succeed the sequence of visual elements 62 that make up the identifier 60 and which can be used to detect the end of the respective instance of visual verification information. In the example of Figure 5A, the end indicator comprises a sequence of two yellow visual elements 62, although any other uniquely identifiable sequence may be used as is convenient.

[0091] Optionally, the visual verification information includes an error checking part 68 comprising one or more visual element 62. The error checking part 68 may be configured to support a parity check or other error checking scheme for at least the indicator 60 part of the visual verification information. In the illustrated embodiment, the error checking part 68 comprises a single visual element 62 located after the last visual element 62 of the indicator 60 and before the end part 66.

[0092] Optionally, the visual verification information includes calibration information for calibrating detection of the visual elements 62 with how the visual elements 62 are rendered by the display 12. The calibration information may comprise a known sequence of visual elements 62 that includes at least one visual element 62 representing each of the different variations that the visual elements 62 can take. In preferred embodiments in which the visual elements 62 can take any one of a plurality of tone(s) and / or colour(s), the calibration information includes a respective visual element 62 set to or otherwise representing each of the possible tone(s) and / or colour(s). Figure 5B shows by way of example calibration information 70 comprising a respective visual element 62 set to each of the possible tone(s) and / or colour(s) (red, blue, yellow, black, white and green in this example) and arranged in a known sequence. Alternatively, the calibration information may comprise a respective visual element 62 set to each of a plurality of colour(s) and / or tone(s) that allow calibration, or other assessment, of how colour(s) and / or tone(s) are displayed on the screen 15, e.g. black, white, red, green and blue, arranged in a known sequence. As illustrated in Figure 5B, the calibration information optionally has an initial part 72, comprising one or more visual element 62, that precedes the calibration sequence 70. The initial part 72 may comprise synchronisation information typically in the form of an indicator of the start of the calibration information 70. The calibration start indicator typically comprises a specific visual element 62 (e.g. a specific colour or tone or pattern) or a specific sequence of visual elements 62 that precede the sequence of visual elements 62 that make up the calibration information 70 and which can be used to detect the start of the calibration information 70 (e.g. such that the first visual element 62 of the calibration sequence 70 occurs immediately after, or a known number of visual elements 62 after, the occurrence of the last visual element 62 of the start indicator). In the example of Figure 5B, the calibration start indicator comprises a sequence of three blue visual elements 62 followed by a red visual element 62, although any other uniquely identifiable sequence may be used as is convenient.

[0093] The initial part 72 may comprise one or more visual element 62 that carries information identifying one or more characteristic of the calibration information 70, for example any one or more of: the number of visual elements 62 in the calibration information; the duration for which each visual element 62 will be displayed; the duration for which the calibration information will be displayed; the number of times the calibration information 70 will be repeated; the type of the visual elements 62; the sequence in which each colour / tone or other variation will occur. This information may be encoded in or otherwise provided by one or more visual elements 62, typically a sequence of visual elements 62, included in the initial part 72, typically preceding the calibration start indicator.

[0094] The calibration information optionally includes an end part 74, comprising one or more visual element 62, that succeeds the calibration information 70. The end part 74 may comprise synchronisation information typically in the form of an indicator of the end of the respective instance of calibration information. The end indicator typically comprises a specific visual element 62 (e.g. a specific colour or tone or pattern) or a specific sequence of visual elements 62 that succeed the sequence of visual elements 62 that make up the calibration information 70 and which can be used to detect the end of the respective instance of calibration information. In the example of Figure 5B, the end indicator comprises a sequence of two green visual elements 62, although any other uniquely identifiable sequence may be used as is convenient.

[0095] Optionally, the calibration information includes an error checking part 76 comprising one or more visual element 62. The error checking part 76 may be configured to support a parity check or other error checking scheme for the calibration information. In the illustrated embodiment, the error checking part 76 comprises a single visual element 62 located after the last visual element 62 of the calibration sequence 70 and before the end part 74.

[0096] Optionally, the calibration information 70 (and optionally any one or more of the initial part 72, end part 74 and error checking part 76 as applicable) is included in, or serves as, the initial part 64 of the visual verification information. The calibration information 70 may precede the start indicator for the identifier 60 or may serve as the start indicator for the identifier 60. More generally, the preferred arrangement is such that the calibration information is displayed before the identifier 60.

[0097] In alternative embodiments, the visual verification information may comprise the calibration information 70 and a different type of identifier 60, i.e. an identifier 60 that is not comprised of a sequence of colour(s) and / or tone(s). For example the identifier 60 may comprise a visual code element, e.g. a QR code, or sequence of visual code elements. In such embodiments, the optical detector 30 may comprise a camera (which is able to detect colours, tones and images) for detecting both the calibration information 70 and the identifier 60, or more than one detector 30 may be provided, e.g. a colour sensor for detecting the calibration information and a camera for detecting the identifier 60, especially if the calibration information 70 and identifier are provided at respective different verification locations 32.

[0098] In preferred embodiments, the visual verification information (including the calibration information as applicable) is incorporated into the primary visual information such that as the primary visual information is rendered on the screen 14, the visual elements 62 are rendered, one at a time according to the relevant sequence, at the respective verification location 32. In preferred embodiments, as the CVI file 27 is played by the media player 16, the visual elements 62 are rendered, one at a time according to the relevant sequence, at the respective verification location 32 as an integral part of the visual presentation displayed on the screen 14. Alternatively, in embodiments where the visual verification information comprises a single visual element, e.g. a QR code or other unique visual code element, the visual verification information is incorporated into the primary visual information such that as the primary visual information is rendered on the screen 14, the visual element is rendered at the verification location(s) 32, the preferred arrangement being such that as the CVI file 27 is played by the media player 16, the visual element 62 is rendered at the verification location(s) 32 as an integral part of the visual presentation displayed on the screen 14.

[0099] The visual verification information may have an associated run time that determines how long it is displayed. The run time may be the same as or less than the run time of the primary visual information. For example, the visual verification information may be displayed on the screen 14 for the whole duration of the primary visual information, or for part of the duration, e.g. during one or more periods during the display of the primary visual information. The visual verification information may be displayed once during display of the primary visual information, or multiple times, as desired. The calibration information may be displayed once during display of the primary visual information, or multiple times, as desired, preferably before the, or each, instance of the identifier 60, or at least before the first instance of the identifier 60.

[0100] Referring in particular to Figures 3, 4A and 4B, the optical detector 30 may be mounted on the screen 14, or elsewhere on the display device 12, by any convenient means. In Figure 3, the optical detector 30 is mounted on the display device 12 by a support structure such as a bracket 34. The optical detector 30 and support structure 34 may comprise part of an embodiment of an optical detection assembly 40, which in preferred embodiments is configured for mounting on the screen 14, or more generally on the display device 12. The optical detection assembly 40 may include electrical and / or electronic circuity, as required, for supporting the operation of the optical detector 30 and / or communicating output signals from the detector 30, e.g. by wired or wireless connection. For example, the circuitry may comprise an RF transmitter, or means for supporting Bluetooth or WiFi communication, and / or signal processing circuitry and / or signal conditioning circuitry as required, and / or any other conventional optical detection circuitry that may be required. Alternatively, the optical detector 30 may be mounted on any other convenient support structure (for example a wall or ceiling). In other embodiments, the optical detector 30 is mounted directly on the screen 14, preferably on the display area 15 of the screen, so that its detection zone covers the verification location 32. To this end, the optical detector 30 may be mounted on the screen 14 by one or more adhesive fixing (in which case the support structure 34 may be omitted). For example, the optical detector 30 may be incorporated into, or placed under, a patch that is fixed to the display area 15 by one or more adhesive fixing. The optical detector 30 may comprise an electronic optical detection circuit provided on a flexible substrate. In any event, the detector 30 is positioned so that it is able to monitor the verification location 32. Typically this involves positioning the detector 30 such that its detection zone coincides with the verification location 32. It will be understood that exact coincidence of the detection zone and verification location is not essential.

[0101] Figures 4A and 4B show respective embodiments of the optical detection assembly 40 comprising a first portion 42 on which the optical detector 30 is provided and a second portion 44 on which at least some and optionally all of the other electrical and / or electronic circuitry 46 of the assembly 40 is provided. The first and second portions 42, 44 are spaced apart from one another and are joined, mechanically and electrically, by a flexible intermediate portion 48. The length of the intermediate portion 48 is such that the first portion 42 may be mounted on the display area 15 of the screen 14 while the second portion 44 is located off the display area 15, preferably at the rear of the screen 14, or optionally at a side, top or bottom of the screen 14. To this end, the flexibility of the intermediate portion 48 is such that it is able to fold around the screen 14. The intermediate portion 48 is preferably non-resiliently flexible. The intermediate portion 48 includes electrical connections between the first and second portions 42, 44 as required, in particular between the detector 30 and the circuitry 46. In some embodiments, the optical detector 30 may be the only electrical / electronic component on the first portion 42, although it will be understood that one or more other electrical / electronic components may be provided on the first portion 42 in addition to the optical detector 30.

[0102] Preferably, an adhesive patch 50, or other adhesive fixing(s) is provided at the first portion 42 for fixing, preferably releasably, the first portion 42 to the display area 15. In preferred embodiments, the first portion 42 is covered by the patch 50 and is located under the patch 50 when adhered to the display surface. Optionally, an adhesive patch, or other adhesive fixing(s) may similarly be provided at the second portion 44 for adhering the second portion 44 to another part, e.g. a rear surface, of the screen 14. Alternatively, no fixing for the second portion 44 may be provided in which case the second portion 44 may hang freely in use. This is convenient in cases where the intermediate portion 48 extends over the top of the screen 14 and the second portion 44 hangs at the rear of the screen 14.

[0103] In the embodiment of Figure 4A, the first portion 42 comprises a rigid circuit substrate, typically a printed circuit board (PCB), on which the optical detector 30 is mounted. The second portion 42 may also comprise a PCB on which the circuitry 46 is provided. The intermediate portion 48 may comprise a flexible cable (e.g. a flat cable) or a flexible circuit. In the embodiment of Figure 4B the first portion 42, second portion 44 and intermediate portion 48 are provided by a flexible circuit and are preferably integrally formed with each other. Preferably, the first portion 42 is one end of the flexible circuit and the second portion 44 is the other end of the flexible circuit. Any conventional flexible circuit may be used, for example of types commonly known as flex circuits, flexible printed circuit boards, flex print or flexi-circuits. In preferred embodiments, therefore, the optical detection assembly 40 is a flexible electronic assembly.

[0104] The preferred configuration of the optical detection assembly 40 described above is advantageous in that the first portion 42 is relatively unobtrusive when mounted on the display area 15 and the second portion 44 may be out of sight, e.g. behind the screen 14, or at least not obscuring the screen. Moreover, the flexibility and the adhesive fixing(s) each facilitate fast and straightforward installation of the assembly 40 on screens of different sizes and shapes. Advantageously, the optical detector 30 can be easily and unobtrusively mounted on the screen, and is well suited to being installed on different types of display device.

[0105] The optical detector 30 may take any suitable conventional form. For example, the optical detector 30 may comprise one or more photodetector, photodiode or other optoelectronic sensor or device. In preferred embodiments, the optical detector 30 comprises a colour sensor such as an RGB colour sensor or other digital colour sensor. Alternatively, the optical detector 30 may comprise an image sensor or a digital camera. Typically, a single optical detector 30 is provided for the, or each, verification location 32. Alternatively, more than one optical detector 30 may be provided for the, or each, verification location 32, e.g. a camera and a simple optical sensor such as a colour sensor. Where there is more than one verification location 32, the same or different types of detector 30 may be used in each location. In preferred embodiments however the optical detector 30 is a simple optical detector (e.g. not an image sensor) comprising a small number, e.g. between 1 , 2, 3 or 4, of photodetectors or photodiodes. Typically, the or each optoelectronic sensor device is incorporated into the circuitry 46, or other suitable electrical and / or electronic circuitry. The circuitry may include any other conventional components that are required to enable the optical detector 30 and / or optical detection circuitry to perform the functions described herein.

[0106] The system 10 includes means for detecting visual verification information from the output signal produced by the optical detector 30, which in the illustrated embodiment is embodied by a reader 80. The reader 80 is configured to analyse output signals generated by the optical detector 30 in order to detect the visual verification information, in particular the identifier 60. The reader 80 is configured to interpret the information contained in the output signal from the detector 30 in order to detect the visual verification information, and in particular to detect the identifier 60. In preferred embodiments, the reader 80 is configured to recognise type of visual element(s) 62, e.g. colours and / or tones and / or visual code elements such as QR codes, represented by the information contained in the output signal in order to detect the visual verification information and in particular to detect the identifier 60 and / or calibration information 70 as applicable. In preferred embodiments, the reader 80 is configured to recognise each visual element 62 individually, for example using the ancillary information (in particular the duration of each visual element 62) or by being pre-programmed with a known duration of each element 62.

[0107] In preferred embodiments, the reader 80 is configured to detect the beginning of the identifier 60 by detecting the synchronisation information in the initial part 64 of the visual verification information. The reader 80 may also obtain other information about the identifier 60 from the initial part 64, for example any one or more of: the number of visual elements 62 in the identifier 60; the duration for which each visual element 62 will be displayed; the duration for which the identifier 60 will be displayed; the number of times the identifier 60 will be repeated; the type of the visual elements 62, all as applicable. Such other information, as applicable, facilitates detection of the identifier 60 by the reader 80 and may be encoded in the initial part 64 in any convenient manner. The reader 80 may be configured to decode any information encoded in the initial part 64 in any convenient manner, e.g. by use of one or more look-up table (LUT). The reader 80 may be configured to detect the end of the identifier 60 by detecting the synchronisation information in the end part 66 of the visual verification information.

[0108] In preferred embodiments, the reader 80 is configured to calibrate its colour and / or tone detection using the calibration information 70 included in the visual verification information. In particular, the reader 80 may use the known sequence of colours contained in the calibration information 70 to calibrate how it recognises colours / tones during analysis of the visual verification information and in particular when detecting the identifier 60. The calibration process allows the reader 80 to accommodate differences in how different display devices 12 may render colours and / or tones, and variations that may arise as a result of how the detector 30 is installed on the screen and on the ambient light.

[0109] The reader 80 may be configured to detect the beginning of the calibration information by detecting the synchronisation information in the initial part 72 of the visual verification information. The reader 80 may also obtain other information about the calibration information 70 from the initial part 72, for example any one or more of: the number of visual elements 62 in the calibration information; the duration for which each visual element 62 will be displayed; the duration for which the calibration information will be displayed; the number of times the calibration information 70 will be repeated; the type of the visual elements 62; the sequence in which each colour / tone or other variation will occur, all as applicable. Such other information, as applicable, facilitates detection of the calibration information by the reader 80 and may be encoded in the initial part 72 in any convenient manner. The reader 80 may be configured to decode any information encoded in the initial part 72 in any convenient manner, e.g. by use of one or more look-up table (LUT). The reader 80 may be configured to detect the end of the calibration information 70 by detecting the synchronisation information in the end part 74.

[0110] In preferred embodiments, the reader 80 is configured to measure one or more visual characteristics of how the visual verification information (and therefore the presentation) is rendered, preferably in respect of any one or more of: illuminance, luminance, brightness and / or colour (e.g. how colours are rendered), in order to facilitate assessment of the quality of the rendered visual presentation and / or to assess the performance of the display device 12. For example, if the measured visual characteristic(s) exceed an upper threshold, or fall below a lower threshold, or vary by more than a threshold amount over time, or exhibits a trend such as increasing, decreasing or otherwise changing over time, this may be taken as an indication of unsatisfactory rendering quality and / or of unsatisfactory performance of the display device 12, and the system 10 may be configured to generate one or more corresponding report or other output(s) for the user. The assessment(s) may involve comparing the measured visual characteristic(s) with a respective corresponding desired, or reference, visual characteristic(s) and / or detecting variations in the measured visual characteristic(s) over time, or otherwise monitoring the measured visual characteristic(s). Conveniently, the reader 80 may be configured to perform the measurement using the detected visual elements 62 of the calibration information 70. Alternatively, for example in embodiments where the calibration sequence 72, 70, 76, 74 is not present, the visual verification information may comprise a sequence of visual elements 62 on which measurement of the relevant visual characteristic(s) may be performed, the sequence conveniently being the same as or similar to the calibration sequence 72, 70, 76, 74, and in respect of which the same or similar description applies. Alternatively, or in addition, the measurement may be performed using any detected visual element(s) 62 of the visual verification information, e.g. visual element(s) of any one or more of: the identifier 60; the calibration information 70; the overhead elements 64, 66, 68, 72, 74, 76. The reader 80, or more particularly the analyser 82, may be configured to perform the relevant assessment(s), or they may be performed by any other convenient component of the system 10, e.g. a component of the control server 20.

[0111] The measuring may be performed using output signal(s) produced by the optical detector 30 in response to detecting one or more visual element 62 in any suitable manner. For example, the output signal(s), or data derived therefrom, may be compared to reference data in order to assess the quality of the rendered visual presentation and / or to monitor how one or more visual presentation is rendered over time, which may involve detecting variations in how the, or each, visual presentation is rendered over time. The output signal(s) may be indicative of any one or more of the detected illuminance, luminance, brightness and / or colour, and so the respective reference data may correspondingly be indicative of any one or more of the detected illuminance, luminance, brightness and / or colour as applicable. The reference data may be external data, e.g. representing one or more industry standard. Alternatively, or in addition, the reference data may be generated by the system 10, e.g. by the reader 80, at one or more designated reference time, e.g. during the calibration process described above, and / or at a first rendering of a given presentation, and / or upon first use of a given display device 12 by the system 10, and / or any other designation reference time(s). Using reference data in respect of one or more designated reference time facilitates monitoring, e.g. detecting variations in, rendered illuminance, luminance, brightness, colour and / or other visual characteristic(s) as applicable over time (e.g. during the rendering of a given presentation and / or over longer periods, e.g. days, weeks, months or years), which may be used to assess the quality of the rendered presentation and / or the performance of the display device 12. Alternatively, the visual characteristic(s) of interest may be monitored over time without comparison to reference data, which still allows the quality of the rendered presentation and / or the performance of the display device 12 to be assessed. The system 10 may be configured to issue a report(s) and / or other output(s) for the user indicating the determined quality of the rendered presentation and / or the performance of the display device 12 as applicable. The measuring, monitoring and assessment, as applicable, may be performed in respect of individual rendered presentations and / or in respect of multiple renderings of any given presentation and / or in respect of renderings of multiple presentations (the same presentation and / or different presentations) on a given display device 12 (the latter facilitating assessment of the performance of the display device 12).

[0112] For example, in preferred embodiments, the system 10 is configured to monitor the brightness of rendered presentations. Brightness may be monitored in respect of individual rendered presentations and / or in respect of multiple renderings of any given presentation and / or in respect of renderings of multiple presentations (the same presentation and / or different presentations) on a given display device 12. The monitoring may involve determining if a maximum brightness level is exceeded, and / or if the brightness falls below a minimum level, and / or if the brightness varies by more than a threshold amount, and / or if the brightness increases or decreases over time. For example, reduction of brightness over time may be an indication that the performance of the display device 12 is deteriorating. Brightness may be measured in any convenient manner. For example, the output of some optical detectors, e.g. some RGB sensors, includes a clear light value (typically in addition to RGB values in the case of RGB sensors), or corresponding value, that may be used as an indication of brightness.

[0113] In preferred embodiments, the reader 80 is configured to perform error checking of the detected visual verification information and may use any conventional error checking technique. For example the reader 80 may error check the detected identifier 60 using error checking information contained in the error checking part 68 and / or may error check the detected calibration information 70 using error checking information contained in the error checking part 76.

[0114] Each visual element 62 is displayed on the screen 14 for a desired, or pre-set, length of time, which is preferably the same for each element 62 and is preferably adjustable and may for example be set by the video editor 21 when creating the CVI file 27. By way of non-limiting example, the configuration may be such that each visual element 62 (or at least each element 62 of the identifier 60 and / or of the calibration information 70) is displayed for 0.1 to 1 seconds (0.2 or 0.3 seconds is preferred). Typically, a play time of 1 to 10 seconds is allocated for the identifier 60. Therefore, if for example 5 seconds of play time is assigned to the identifier 60 and the display time for each visual element 62 is 0.2 seconds, then the identifier 60 may contain 25 visual elements 62. Corresponding information is provided in the initial part 64 that enables the reader 80 to detect the identifier 60.

[0115] In preferred embodiments, the reader 80 is configured to check, or monitor, at least part of the visual verification information in order to detect undesirable aspects of the rendering of the respective visual presentation, such as buffering or jitter. The system 10 may be configured to issue a report(s) and / or other output(s) for the user identifying any detected undesirable aspects of the rendering of the respective visual presentation, such as buffering or jitter. The checking, or monitoring, may involve determining the length of time, or at least an indication of the length of time, for which one or more visual element 62 is displayed, and comparing the determined duration with an expected duration (i.e. the desired, or pre-set, duration for displaying the respective visual element(s) 62). If the determined, or measured, duration differs from the expected duration (e.g. by more than a preset threshold amount), then this is an indication that the rendering of the visual verification information (and therefore of the associated presentation) is unsatisfactory. In particular, if it is determined that the determined, or measured, duration exceeds the expected duration (e.g. by more than a threshold amount), then this is an indication that buffering or jitter has adversely affected the rendering. The reader 80 may be configured to record instances of discrepancy between the determined duration and expected duration, and the system may use this information to assess the quality of the rendered visual presentation. Optionally, the reader 80 may record data indicating one or more aspect of the discrepancy such as whether the determined duration exceeds or is less than the expected duration and / or the amount by which the determined duration exceeds or is less than the expected duration; such information may be used by the system to assess the quality of the rendered visual presentation. This checking or monitoring process may be performed using any of the rendered visual element(s) 62, preferably using a known sequence of visual elements 62 (e.g. all or part of the identifier 60 or all or part of the calibration information 70) and / or using any sequence of non-identical visual elements 62 (preferably a sequence in which the same visual element 62 does not appear in immediate succession) included in the visual verification information and / or provided separately from the visual verification information. For example in embodiments in which the visual verification information is rendered during only part of the rendering of the respective visual presentation, an additional sequence of visual elements 62 may be rendered during at least some of, and preferably all of, or substantially all of, the remainder of the visual presentation to facilitate the checking / monitoring process. Advantageously, performing this checking or monitoring process using all or part of the identifier 60, or other part of the visual verification information facilitates associating the corresponding quality assessment with the respective visual presentation.

[0116] The reader 80 may be configured to determine the duration of each rendered visual element 62 in any convenient manner. For example, in typical embodiments, the reader 80 is configured to sample the visual verification information at a sampling rate that causes at least one, and preferably more than one, sample of each rendered visual element 62 to be taken. In preferred embodiments the sampling rate may depend on the desired, or pre-set, duration of each visual element 62, and is preferably determined in accordance with the Nyquist sampling theorem. For example, in embodiments where the desired, or pre-set, duration of each visual element 62 is, say, 0.2 or 0.3 seconds, the reader 80 may be configured to sample the visual verification information every 50ms. In any event, for a given sampling rate, the number of samples of any given visual element 62 that is actually taken is an indication of the display duration of the rendered visual element 62. Similarly, for a known sampling rate and the desired, or pre-set, duration of each visual element 62, there is an expected number of samples per visual element 62. Therefore, for any given visual element(s) 62, if the actual number of samples taken exceeds or is less than the expected number of samples, this is an indication that the duration of the rendered visual element 62 was longer or shorter (respectively) than the expected duration. The number of samples by which the actual number exceeds or is less than the expected number is an indication of by how much the actual duration exceeded or was less than the expected duration. The reader 80 may record the number of samples taken for each visual element 62 (or each visual element 62 in respect of which this analysis is to be performed) for use in the checking or monitoring process described above.

[0117] For example, for any given visual element 62, if the actual number of samples exceeds the expected number of samples, or exceeds the expected number of samples by more than a threshold amount, then this may be an indication that there is an adverse rendering aspect such as buffering or jitter. Alternatively or in addition, if the actual number of samples is less than the expected number of samples, or is less than the expected number of samples by more than a threshold amount, then this may be an indication that there is an adverse rendering aspect such as buffering or jitter (e.g. where a portion of the presentation is skipped after buffering). Alternatively, or in addition, a sequence of actual number of samples exceeding the expected number for a given visual element 62 followed by the actual number of samples being less than the expected number for the next, or a subsequent, visual element 62, may be an indication that there is an adverse rendering aspect such as buffering or jitter (e.g. where a portion of the presentation is skipped after buffering). The reader 80 may record sample counts for subsequent analysis by the system or by the user, and / or may record detected adverse rendering events based on the sample counts. An assessment of the quality of the rendered presentation may be made based on the number of adverse rendering events that are detected for the presentation and / or on the magnitude of those events (i.e. the extent to which the actual number of samples exceeded or was less than the expected number). Alternatively or in addition, for a given presentation, the reader 80 may record the largest detected discrepancy (and optionally only the largest detected discrepancy) between the actual duration of a rendered visual element (e.g. the actual number of samples for that visual element) and the expected duration of the rendered visual element (e.g. the expected number of samples for that visual element), and this information may be used by the system and / or the user as indication of the quality of the rendering of the presentation. The reader 80 may be configured to record instances of visual verification information, or at least the identifier 60, that it detects and / or to record data that is indicative of instances of visual verification information (or at least the identifier 60) that it detects. In preferred embodiments, the reader 80 is configured to generate a computer-usable (typically digital) representation, e.g. a code, representing the detected identifier 60. As is illustrated by way of example in Figure 6, generating the code, or other representation, may involve assigning a respective computer-usable (typically digital) symbol or character, e.g. a respective letter or numeral, to each detected colour and / or tone in the identifier 60. In some embodiments, e.g. where the identifier 60 comprises a QR code or other visual code element, it not necessary to generate another code of the type illustrated in Figure 6. The reader 80 may include memory or other storage means for storing detected identifiers 60, in their detected form or coded form as applicable.

[0118] The reader 80 may be configured to record and / or associate ancillary information with each identifier 60, and therefore each presentation, that it detects. The ancillary information may for example include any one or more of: the time and / or date at which the identifier 60 is detected; the duration for which the respective visual presentation was played; the geographical location at which the identifier 60 is detected; a unique ID of the reader 80; and the number of wirelessly enabled electronic devices detected in the vicinity of the display device 12 during the, or each, rendering of the respective presentation.

[0119] The geographical location may be determined by a GPS receiver 84, which may be included in the reader 80 or in the circuitry 46 as is convenient. The time may be determined by an internal clock (not shown) or an external reference clock (not shown). For example, the time and date may be determined from the GPS clock via the GPS receiver 84.

[0120] In order to detect wirelessly enabled devices (e.g. mobile phones or other computer devices) in the vicinity of the display device 12, the system preferably includes at least one wireless receiver 85. The, or each, wireless receiver 85 may be included in the reader 80 or in the circuitry 46 as is convenient. Conveniently, the wireless receiver 85 is a Bluetooth receiver, but may be a wireless receiver that supports any wireless communication standard(s) that are commonly supported by wirelessly enabled devices, e.g. NFC, Zigbee, Wifi and so on. In preferred embodiments, the reader 80 is configured to detect, using the or each wireless receiver 85, all discoverable wirelessly enabled devices in the vicinity of the display device 12 during the, or each, rendering of a given visual presentation, and to record the number of detected devices. Typically, a device is determined to be in the vicinity of the display device 12 if it is detectable by the receiver 85, i.e. within the detection range of the receiver 85. The receiver 85 may be configured or may be configurable to have a desired detection range, optionally an adjustable detection range. The number of detected devices is recorded in association with the respective visual presentation, and / or with the respective rendering of the respective visual presentation, and may be included in report(s) for the respective presentation to provide an indication of audience size. Detecting the electronic devices may involve detecting the MAC address of the device, but may alternatively, or in addition, involve detecting a device ID, or other signature of the device. Typically, the system does not store each MAC address or other device ID. However, the MAC address (or other device ID) typically indicates the type of device, e.g. phone, tablet computer, vehicle computer etc., and in preferred embodiments, the type of each detected device is recorded. In preferred embodiments, the reader 80 records the duration for which each detected device is determined to be in the vicinity of the display device 12, e.g. by recording an arrival time, a departure time and / or a dwell time.

[0121] In preferred embodiments, the detected visual verification information, in particular the detected identifier 60 and any association information, is provided to the control system 20 and may be stored in any convenient memory or other storage means 88. The control system 20 may include a data manager 86 configured to provide reports to the respective client 18 in relation to the display of primary visual information relating to that client 18 based on the respective detected visual verification information, in particular the detected identifier 60 and any association information. The data manager 86 may be implemented by one or more computer program as is convenient. It is noted that while Figure 1 shows the video editor 21 and data manager 86 as being co-located, e.g. on the same server or cloud platform, they may alternatively be implemented separately and / or remotely of each other, e.g. on respective separate servers or cloud platforms, all being part of the control system 20, which as indicated above may be distributed.

[0122] In preferred embodiments, the reader 80 is configured to record the detected calibration information 70 and / or to record data that is indicative of each colour and / or tone that is present in the detected calibration information 70. The reader 80 may be configured to generate a computer-usable (typically digital) representation, e.g. a code, representing each detected colour and / or tone, which may for example involve assigning a respective computer-usable (typically digital) symbol or character, e.g. a respective letter or numeral, to each detected colour and / or tone in the calibration information 70. The reader 80 may include memory or other storage means for storing the detected calibration information 70. The reader 80 may be configured to associate the detected calibration information 70 with ancillary information such as any one or more of: the time and / or date on which the calibration information 70 is detected; the geographical location at which the calibration information 70 is detected; and a unique ID of the reader 80. Advantageously, the reader 80 is configured to send the detected calibration information 70, together with any ancillary information, to the server 20. The reader 80 or the server 20, for example at the data manager 86, may be configured to associate each instance of detected identifier 60 with corresponding calibration information 70, e.g. based on the respective ancillary information. The data manager 86, or other part of the server 20, may be configured to monitor the detected calibration information 70 in order to, for example, detect changes (e.g. deterioration) in how the respective display 12 rendered colours and / or tones over time, or otherwise to monitor the quality of how the display 12 renders colours and / or tones. The server 20 may be configured to provide reports, e.g. to the clients 18, in relation to the quality of the display based on the detected calibration information 70. The quality information may be associated with one or more rendered visual presentations as determined by which detected identifier(s) 60 are associated with the respective calibration information 70. It is noted that the detected calibration information may be communicated to the server 20 even if the identifier 60 is not a colour / tone based identifier, e.g. of the type shown in Figure 5A, since it still serves as a metric on which the quality of the display can be assessed.

[0123] In the illustrated embodiment, the analysis of the visual verification information is performed by analyser 82, which may be implemented in computer software and / or hardware as is convenient. Typically, the reader 80 comprises at least one microprocessor, microcontroller or other processor that is programmed or otherwise configured to implement the analyser 82 and / or otherwise to implement the functionality described herein. In preferred embodiments, the reader 80, including the analyser 82, is located at the same site as the detector 30 and display device 12, e.g. mounted on the display device 12 or otherwise located beside or close to the display device 12. The reader 80 may be in communication with the optical detector 30, typically via the circuitry 46, by a wired or wireless communication link, and the reader 80 and detector 30 or circuitry 46 may include conventional communication means to support the communication link. Alternatively, the reader 80 may be integrally formed with the circuitry 46.

[0124] In preferred embodiments, the reader 80 is in communication with the control server 20 across the telecommunications network 11 and the reader 80 and control server 20 include corresponding wired and / or wireless communication means as required. As such, the reader 80 may provide the detected visual verification information to the server 20 across the network 11 .

[0125] In alternative embodiments, the reader 80, or at least the analyser 82, may be located remotely from the optical detector 30 and circuitry 46, for example being provided on the control server 20. In such embodiments, the optical detector 30 or circuitry 46 may be provided with means for communicating with the server 20 across the network 11 .

[0126] In use of the preferred embodiment, the primary visual information is displayed on the screen 14, and the visual verification information is simultaneously displayed at the verification location 32. The optical detector 30 monitors the verification location 32 in order to detect the visual verification information, in particular the identifier 60. The display of the primary visual information is verified by detecting the display of the corresponding identifier 60. The playing of the primary visual information is only verifiable if the primary visual information, together with the corresponding visual verification information, is actually displayed on the screen 14. Hence, if the CVI file 27 is sent to the display device 12 but the screen 14 is not switched on, or if it is tuned to another channel, or if the display device 12 is switched to a different input, the playing of the primary visual information is not verifiable.

[0127] In use of the preferred embodiment, one or more CVI file 27 is downloaded from the server 20 and uploaded or otherwise provided to a single digital media player (e.g. signage player), or to multiple digital players, or to a platform from where it can be transmitted to multiple digital players, for display on respective screens according to the relevant scheduling requirements. The respective reader 80, in conjunction with the respective optical detector 30, monitors the relevant area 72 or areas of the screen 15 in order to detect the visual verification information. Using the known synchronising information at the start of the visual verification information to know when the unique identifier 60 begins, the reader 80 collates the unique series of colours / tones which follow and stores it in a database or other convenient storage means for either real-time or later transmission to the server 20 via the network 11 . Additional information may be transmitted to the server 20 including but not limited to any one or more of: geographical location of the reader 80 / detector 30; the time of day and date that the detection took place; the duration of the rendered visual presentation; and encoded security information which identifies the reader 80 that detected the identifier 60. For example, in typical embodiments, the information sent by the reader 80 includes, for each visual presentation detected, the start time of the presentation, the duration of the presentation, and the identifier 60. The detected calibration information 70 may be communicated to the server 30 periodically or otherwise as required. Once the information is received by the server 20 a variety of reports can be produced which may present the details of the verified display content, where and when it was displayed, and with the option of using other information collected by the reader 80, e.g. to provide information of the audience which was present when the content was displayed.

[0128] It will be apparent that preferred embodiments allow the playing of visual presentations or the like to be verified independently of the media player that is playing the presentations. This is in contrast to conventional solutions that require specialised media players that are capable of creating and displaying overlay data that is separate from the visual presentation but which is displayed with the presentation an overlay. In preferred embodiments, this is achieved by pre-embedding (e.g. using a cloud service prior to distribution of the visual presentation to the player network) visual verification information comprising a sequence of different colours (or other elements) into the original version of the presentation. This sequence is essentially a unique and traceable ‘fingerprint’ which will be played on any display on which the fingerprinted presentation is played. The calibration process further facilitates independence from rendering variations between different types of media player, from changes in rendering performance over time and from variations that might arise because of how the optical detector is set up or ambient lighting conditions. The checking process for detecting undesirable aspects of the rendering such as buffering or jitter, and the measuring process for visual characteristic(s) of the rendering, e.g. in terms of illuminance, luminance, brightness and / or colour (in particular how colours are rendered), facilitate assessment of the quality of the rendered visual presentation. It will be understood that the calibration process(es), checking process(es) and measuring process(es) disclosed herein are not limited to use with visual presentations in which the verification information is incorporated into the same computer file as the primary visual information as described herein, and may alternatively be used with other verification systems, e.g. in which the visual verification information is overlayed on the primary visual information during play time. In typical embodiments the visual verification information, or fingerprint, includes one or more sequence of visual elements, e.g. colour blocks, encoding information that enables the system to not only identify the presentation, but also to assess its quality and / or calibrate according to the rendering conditions, and / or to qualify, quantify and assess the quality of the content as it is displayed, advantageously enabling the system to perform further processing at a later time to extract relevant information as required.

[0129] The invention is not limited to the embodiment(s) described herein but can be amended or modified without departing from the scope of the present invention.

Claims

CLAIMS:

1. A method of verifying display of primary visual information on a screen of at least one electronic visual display device, the method comprising: combining said primary visual information with visual verification information to create combined primary and verification visual information in a computer-usable format; causing said combined primary and verification visual information to be rendered on the screen of said at least one visual display device; monitoring said screen using at least one optical detector to detect display of said visual verification information on said screen.

2. The method of claim 1 , wherein said combining involves creating a computer file containing data representing said combined primary and verification visual information.

3. The method of claim 1 or 2, wherein said causing involves causing said combined primary and verification visual information to be rendered on the screen of said at least one visual display device by at least one media player, and wherein said combining involves creating a computer file containing data representing said combined primary and verification visual information, said computer file being of a format that is suitable for playing by said at least one media player.

4. The method of any preceding claim, wherein said combining involves obtaining said primary visual information in a computer-usable format, rendering said primary visual information, combining said visual verification information with said primary visual information during said rendering, preferably by overlaying said primary visual information with said visual verification information, and wherein, preferably, said rendering involves rendering said primary visual information using a visual media editor.

5. The method of claim 4, wherein said combining said visual verification information with said primary visual information during said rendering is performed by or using a visual media editor.

6. The method of any one of claims 4 or 5, wherein said creating combined primary and verification visual information in a computer-usable format involves recording the combined primary and verification visual information during said rendering.

7. The method of any preceding claim, wherein said combining is performed at or by a first computing system, preferably being a cloud computing system, said at least one visual display device being located at at least one site, and wherein typically one or more media player is located at said at least one site for rendering said combined primary and verification visual information on thescreen, said method including communicating said combined primary and verification visual information in said computer-usable format to said at least one site, typically to said one or more media player, via a telecommunications network.

8. The method of any preceding claim, further including displaying said visual verification information at at least one verification location on a display area of said screen, and monitoring said at least one location using said at least one optical detector, and wherein, preferably, said at least one verification location is located at a peripheral part of said display area, preferably at a corner or side of said display area.

9. The method of any preceding claim, wherein said primary visual information comprises a visual presentation, and wherein said combined primary and verification visual information comprises said visual presentation modified to include said visual verification information.

10. The method of any preceding claim, wherein said visual verification information comprises a sequence of visual elements for displaying on the screen and that are detectable by said at least one optical detector, and wherein said method preferably includes combining said visual verification information with said primary visual information such that said visual elements are displayed one at a time according to the sequence, and wherein, preferably, each visual element is set to, or otherwise configured to represent, any one of a plurality of colours and / or a plurality of tones, and / or optionally a plurality of patterns.11 . The method of claim 10, wherein said sequence of visual elements comprises at least one visual element, preferably a plurality of said visual elements, configured to provide an identifier, and wherein said identifier identifies, preferably uniquely identifies, said combined primary and verification visual information.

12. The method of any one of claims 10 or 11 , wherein said sequence of visual elements comprises an initial part, said initial part comprising one or more of said visual elements configured to provide synchronisation information and / or one or more of said visual elements configured to provide ancillary information, wherein said ancillary information may comprise the duration for which each visual element will be displayed.

13. The method of claim 12 when dependent on claim 11 , wherein said initial part precedes said identifier and wherein said ancillary information may comprise any one or more of: the number of visual elements in the identifier; the duration for which each visual element of the identifier will be displayed; the duration for which the identifier will be displayed.

14. The method of any one of claims 10 to 13, wherein said sequence of visual elements comprises an end part, said end part comprising one or more of said visual elements configured to providesynchronisation information and / or one or more of said visual elements configured to provide error checking information.

15. The method of any one of claims 10 to 14, wherein said sequence of visual elements comprises a sequence of visual elements configured to provide calibration information, and wherein in said calibration information optionally comprises at least one visual element representing each of the different variations that the visual elements can take arranged in a known sequence, or a known sequence of visual elements set to a respective different colour and / or tone to allow calibration of the screen.

16. The method of claim 15 when dependent on claim 10, wherein said calibration information comprises at least one visual element representing each of the different colours and / or tones and / or patterns that the visual elements can take arranged in a known sequence, or a known sequence of visual elements set to a respective different colour and / or tone to allow calibration of the screen.

17. The method of any one of claims 15 or 16 when dependent on claim 12, wherein said calibration information comprises or is included in said initial part.

18. The method of any preceding claim, wherein said visual verification information comprises at least one visual element configured to provide an identifier, and wherein said identifier identifies, preferably uniquely identifies, said combined primary and verification visual information, and wherein, optionally, said identifier comprises a visual element in the form of a visual code, for example a QR code.

19. The method of any preceding claim, further including analysing output signals generated by the optical detector in order to detect the visual verification information.

20. The method of claim 19 when dependent on claim 10, wherein said analysing involves recognising colours and / or tones and / or patterns and / or images represented by the information contained in the output signal in order to detect the visual verification information.21 . The method of claim 19 or 20 when dependent on claim 10, wherein said analysing involves detecting the visual verification information by detecting each visual element.

22. The method of any one of claims 19 to 21 when dependent on claim 1 1 , wherein said analysing involves detecting said identifier.

23. The method of any one of claims 19 to 22 when dependent on claim 12, wherein said analysing involves detecting said initial part and synchronising detection of the visual verification using said synchronisation information and / or extracting said ancillary information.

24. The method of any one of claims 19 to 23 when dependent on claim 14, wherein said analysing involves detecting said end part and synchronising detection of the visual verification using said synchronisation information and / or extracting said error checking information and performing an error checking process on said visual verification information using said error checking information.

25. The method of any one of claims 19 to 24 when dependent on claim 15, wherein said analysing involves detecting said calibration information and using said calibration information to calibrate detection of said visual verification information.

26. The method of any preceding claim, further including verifying display of said primary visual information by determining that said visual verification information is detected on said screen by said at least one optical detector, and wherein the method optionally includes associating ancillary information with the detected identifier, wherein the ancillary information may comprise any one or more of: the time and / or date at which the identifier is detected; the duration for which the respective visual presentation was played; the geographical location at which the identifier is detected; and a unique ID of a reader that detected the identifier.

27. The method of claim 22 or 26 when dependent on claim 7, including communicating said identifier, preferably with said associated ancillary information, to said first computing system, and, preferably, verifying at said first computing system the display of said primary visual information using said identifier and, optionally, said associated ancillary information, and wherein the method optionally includes determining one or more characteristics, for example relating to quality, of how said visual information is displayed by the respective display device using said calibration information, preferably using multiple instances of said calibration information detected over time, optionally based on variations in said calibration information over time.

28. The method of claim 27 when dependent on claim 7, including communicating said calibration information to said first computing system and, preferably, performing said determining of one or more characteristics at said first computing system.

29. The method of any preceding claim, including measuring at least one visual characteristic of how the visual verification information is rendered, comparing the, or each, measured visual characteristic with a respective corresponding desired visual characteristic, and providing an assessment of the quality of the rendered primary visual information based on the comparison, wherein, optionally, said at least one visual characteristic comprises any one or more of: illuminance, luminance, brightness and / or colour, in particular how one or more colours are rendered.

30. The method of claim 10 and any one of claims 11 to 29 when dependent on claim 10, further including determining a duration for which at least one visual element of the visual verification information is displayed, and comparing the determined duration with an expected duration, and preferably providing an assessment of the quality of the rendered primary visual information basedon the comparison and / or providing a report indicating the results of the comparison or otherwise being based on the comparison.31 . The method of claim 30, wherein said comparing involves determining if the determined duration differs from the expected duration, preferably by more than a threshold amount, and, preferably, upon determining that the determined duration differs from the expected duration, preferably by more than the threshold amount, providing an indication that the rendering of the visual verification information and / or of the primary visual information is unsatisfactory.

32. The method of claim 31 , further including, upon determining that the determined duration exceeds the expected duration, preferably by more than the threshold amount, providing an indication that buffering or jitter has adversely affected the rendering.

33. The method of any one of claims 30 to 32, wherein said determining a duration for which at least one visual element of the visual verification information is displayed involves sampling the visual verification at a sampling rate and determining the number of samples taken for the, or each, visual element.

34. The method of any preceding claim including measuring one or more visual characteristics of how the visual verification information is rendered, preferably in respect of any one or more of: illuminance, luminance, brightness and / or colour, and preferably providing an assessment or indication of the quality of the rendered visual presentation and / or of the performance of the display device based on the measuring, wherein the method may involve, if the measured visual characteristic(s) exceed an upper threshold, or fall below a lower threshold, or vary by more than a threshold amount over time, or exhibits a trend such as increasing, decreasing or otherwise changing over time, providing an indication of unsatisfactory rendering quality and / or of unsatisfactory performance of the display device, and / or may involve generating one or more corresponding report or other output(s) for the user, and wherein the assessment may involve comparing the measured visual characteristic(s) with a respective corresponding desired, or reference, visual characteristic(s) and / or detecting variations in the measured visual characteristic(s) over time, or otherwise monitoring the measured visual characteristic(s).

35. The method of any preceding claim, further including detecting, conveniently using one or more wireless receiver, wirelessly enabled electronic devices in the vicinity of the display device during the, or each, rendering of the primary visual information, and to record the number of detected devices in association with the primary visual information and / or with the respective rendering of the primary visual information.

36. A system for verifying display of primary visual information on a screen of at least one electronic visual display device, the system comprising:means for combining said primary visual information with visual verification information to create combined primary and verification visual information in a computer-usable format; means for causing said combined primary and verification visual information to be rendered on the screen of said at least one visual display device; and means for monitoring said screen using at least one optical detector to detect display of said visual verification information on said screen.

37. The system of claim 36, wherein said at least one optical detector comprises one or more photodetector or other optoelectronic device, preferably a colour sensor, a greyscale sensor, or a binary (e.g. black and white) sensor, and / or wherein said at least one optical detector comprises an image sensor or a digital camera.

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