The present disclosure relates to the display of interactive television applications, in particular although not exclusively on a television display device such as a television set.

BACKGROUND Interactive television applications can be displayed on a wide variety of display devices, for example television sets, computer screens, portable devices such as mobile phones, tablets, laptops, etc. It is known in general to adapt interactive displays as a function of the display device, for example serving a different version of a website to a mobile device then to a desktop computer. It is also known to adapt the logical resolution (number of pixels in each dimension) of a video signal as a function of the resolution available on the display device, using sub-sampling or interpolation as required, so as to be able to display the same video on different display devices.

A number of quantities can describe the display of a display device, for example the following quantities. A display device has a physical resolution (number of pixels in each dimension) and hence a physical pixel density given by the resolution relative to the physical size of the display device, as illustrated in Figure 1. For example pixel density may be calculated as the ratio of the square root of the sum of the respective squares of the number of pixels in each dimension divided by the screen diagonal lengths; the number of pixels in one dimension divided by the length of that dimension; the average of the number of pixels in one dimension divided by the length of that dimension and the number of pixels in the other dimension divided by the length of that dimension, etc.

SUMMARY

While some degree of adaptation to the display device for the display of web sites or video signals is known, a more fine-grained approach would enable better use of screen real estate to better exploit the capabilities of the display device to convey information to a user of an interactive television application.

In a first aspect of the disclosure, there is provided a method of generating a display of an interactive television application for display on a display device. The method comprises determining display size information for the display device. Pixel density information for the display device is determined using resolution information for the interactive application and display size information. One or more display layout parameters of the interactive application are set in dependence on the pixel density information and the interactive application is displayed on the display device in accordance with the layout parameters.

Advantageously, by adjusting layout parameters based on pixel density information, the amount of information that can be displayed to a user of the interactive application can be adjusted by adjusting layout parameters to increase or decrease the amount of information based on the available pixel density. Layout parameters that can be adjusted may comprise one or more of: font size; rows in a list; rows and/or columns in a grid; timescale of a grid guide; size of a PIP (picture in picture) window; etc.

For example, more rows of a television grid guide and a higher resolution time axis using smaller fonts can be displayed on a high resolution large screen television set than on a television set of the same size having a lower resolution. Likewise, on screens having the same resolution (number of pixels in each dimension) more information can be displayed per unit of length on a smaller screen than on a larger screen. Thus, by considering pixel density and adjusting layout parameters accordingly, better use can be made of the capacity of a given screen to display information than by, for example, merely adjusting video resolution based on the physical resolution of the display device.

In some embodiments, the resolution information comprises logical resolution information and the pixel density comprises a logical pixel density. The logical resolution is the resolution of a display screen as generated by the interactive application, based on the number of pixels generated for the display screens of the interactive application. An interactive application may generate display screens at a logical resolution, which may correspond to the physical resolution of the display device for which the display screens are generated (in which case the logical resolution is the same as the physical resolution of the display device) or not (in which case the display device will have to sub-sample or interpolate the display screens). For example, an interactive television application may generate a SD screen resolution display, while the display device may have a HD screen resolution. Corresponding to the logical resolution is a logical pixel density, that is the logical resolution relative to the physical size of the display device, calculated analogous to the physical pixel density discussed above, for example using one of the various measures described above for the calculation of physical pixel density mutatis mutandis. It will be understood that the logical pixel density may or may not be the same as the physical pixel density.

In some embodiments, the resolution information comprises logical resolution information and physical resolution information (i.e. information about the resolution of the physical display screen, based on the number of physical pixels of the display screen). The physical resolution may be obtained in the same way as display size information.

Determining the logical pixel density may comprise using the lower of the logical and physical resolution to determine the logical pixel density, for example using one of the various measures described above for the calculation of physical pixel density mutatis mutandis. Additionally or alternatively, generating displays of the interactive application may comprise setting the logical resolution to be the same, or to be the same or less than, the physical resolution. In some embodiments, the display size information is determined using information obtained from the display device, for example in Extended Display Identification Data (EDID) format. Where the display device is separate from the device generating the display screens for the interactive application, this information may be obtained, for example, over a cable connecting the two devices, for example a HDMI cable. Where the display device is sufficiently EDID compliant to provide the display size as part of the EDID, the display size information can be obtained directly from for example, the EDID information (or other information directly received from the display device).

In some embodiments, the display size information is derived from type or model information about the display device. For example, type or model information can be derived from manufacturer name and serial number and/or product type information included in the EDID information or EDID information can be used directly as type or model information. Information identifying the model or type may be used to look up the display size in a database, for example over a communication network such as the Internet. The database may be the entire World Wide Web and look up may comprise a web search.

In addition to setting the display layout parameters of the interactive application in dependence on the pixel density information, the layout parameters may be set in additional dependence on information related to a viewing distance from a user of the interactive application to the display screen. The viewing distance may be a parameter that is stored for use in setting the layout parameters, for example subsequent to a setup procedure in which the user specifies a value for the viewing distance. Alternatively or additionally, viewing distance information may be determined using a sensor.

For example, a camera such as a web camera, for example built into the display device, the device generating the screens for the interactive application or a separate device, can be used to capture a scene in front of the display screen. The scene is processed to detect a face and the distance from the display screen to the face is inferred based on an average face size. Alternatively or additionally, a microphone and loudspeaker of one or more of these devices may be used to determine viewing distance using an echolocation technique. A dedicated sensor may also be used instead or in addition to the above, for example an ultrasound sensor.

Viewing distance information may or may not be directly representative of viewing distance, as long as there is a sufficient correlation between the viewing distance information and actual viewing distance to enable layout parameters to be set.

The interactive application may, for example, be an interactive television guide or electronic program guide (EPG), a social media application, a video on demand access application or an application combining one or more of these functions. The application may run on a device separate from the display device, for example on a set-top box connected to a television set as a display device, or the two devices may be integrated, for example in a smart TV set.

In a second aspect of the disclosure, there is provided a method of generating a display of an interactive television application for display on a display device. The method comprises determining viewing distance information related to a viewing distance of a user of the interactive application from the display device. One or more display layout parameters of the interactive application are set in dependence on the viewing distance information and the interactive application is displayed on the display device in accordance with the layout parameters. Viewing distance information may be determined, for example, as described above.

In a third aspect, there is provided a device for generating a display of an interactive television application. The device comprisesa memory for storing an interactive application and one or more display layout parameters of the interactive application and a processor configured to implement one or more methods as described above. The device may, for example, be a set-top box for connection to television set as a display, or other devices as described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Specific embodiments are now described by way of example, with reference to the accompanying drawings, in which:

Figure 1 illustrates calculation of pixel density in pixel per inch (ppi);

Figure 2 illustrates a system for displaying an interactive television application; Figure 3 illustrates a method of displaying an interactive television application;

Figure 4 illustrates a method of obtaining display size information; and

Figure 5 illustrates a system for displaying an interactive television application comprising viewing distance sensors. SPECIFIC DESCRIPTION

With reference to Figure 2, a set-top box 100 comprises a receiver 102 for receiving a broadcast signal, for example a terrestrial television signal, a satellite signal or a cable signal. A communications interface 104 is connected to a communication network, for example via a router. The communication network may be a local area network connecting a number of devices and/or the Internet. A processor 106 comprises processing circuitry 108 and memory 1 10 and is connected to the communications interface 104 and the receiver 102 to process signals therefrom. The processing circuitry 108 comprises a number of modules, including modules for processing broadcast signals (demultiplexing, decoding, etc) to generate a video signals corresponding to broadcast channels for display, for receiving and sending signals via the communications interface 104 and for running interactive applications, including generating display screens for the interactive applications. A display interface 1 12 is connected to the processor 106 to interface between the set-top box 100 and the television set 200 and to generate control signals for controlling the display of the television set 200 to display the video and display screens generated by the processor 106. The modules of the processing circuitry 108 may correspond to different hardware devices or may correspond to logical modules of software (e.g. firmware) running on a general purpose or specialised processor. The processing circuitry thus can comprise any number of one or more processors and devices and the modules may be distributed among these processors or devices in any convenient way ranging from all modules being implemented in a single processor or hardware device, for example a System on Chip (SoC), to each module being implemented in a separate processor or hardware device. All described functionality can be implemented in any combination of dedicated hardware, general purpose hardware and suitable software. The television set 200 comprises a display 202 for displaying video and display screens received from the set-top box 100, specifically from the display interface 1 12. The television set 200 further sends device information, for example in the EDID format, to the set-top box 100, which is received by the display interface 1 12 and passed to the processor 106 for processing.

The processor 106, as mentioned above, is configured for running an interactive application, for example a television program guide, and to generate display screens 204 of the interactive application for display on the television set 200. A method of generating such display screens and causing their display is now described with reference to Figure 3.

With reference to Figures 3, the processor 106 determines display size information, for example vertical and horizontal measurements of the display 202 at step 302. Display size information may be obtained directly, for example from an EDID signal received from the television set 200 or indirectly, for example by querying the memory 1 10, in which display size information has been stored during a setup procedure, for example entered by a user. In some embodiments, the display size is derived from the EDID signal and then stored in the memory 1 10 for later use as described above. An alternative method for determining display size information, either on the fly when required or for storage of the display size information in the memory 1 10 for later use is described below with reference to Figure 4.

At step 304, a logical pixel density is determined, that is a pixel density calculated for the logical resolution of the display screens generated by the interactive application relative to the physical display size, as described above for the physical pixel density with reference to Figure 1. At step 306 layout parameters of the interactive application are set based on the determined logical pixel density. The parameters are set so that the amount of information displayed is commensurate with the logical pixel density. For example, a high logical pixel density means that a smaller font size will be legible to a user of the interactive application, allowing smaller font sizes to be used and as a result to include more information in lists, etc in the display screens of the interactive application. In some embodiments, the processor 106 also derives physical display resolution (the physical pixel resolution of the display device) in analogous manner as display size information. The physical display resolution may be used to adjust the logical resolution, for example to be less or equal to the physical display resolution. Alternatively or additionally, the physical resolution may be used in determining the logical pixel density. For example, the logical pixel density may be calculated using the lower of the physical and logical resolution relative to the physical display size.

For example, the interactive application may be a television program guide having one or more display screens in a grid guide format as depicted in Figure 2. The layout parameters of these display screens may be adjusted based on the logical pixel density so that more rows and columns are displayed for higher logical pixel densities. More generally, one or more of the following parameters of the interactive application are adjusted as a function of logical pixel density: font size; rows in a list; rows and/or columns in the grid; timescale of a grid guide; size of a picture in picture (PIP) window.

Using the layout parameters set at step 306, the display screens of the interactive television application are generated based on these layout parameters and display of the interactive application on the display 202 is caused at step 308. The layout parameters are used, in some embodiments, as inputs into CSS stylesheets to adjust the appearance of a browser based user interface dynamically. More generally, user interfaces coded to lay out the display against a set of rules rather than rigid pre-defined sizes and positions, in some embodiments, use the layout parameters to increase or decrease the amount of information or detail shown. For example there is approximately a 25% difference in pixel density / height between a 32" and 42" television screen. If a row of an electronic program guide (EPG) is 200 pixel in height, it could be compacted by 40 pixels to 160 pixels in height through reduction of font size, spacing, etc. and yet will appear the same size on a 42" television at 160 pixels in height as on a 32" television at 200 pixels in height for the same viewing distance. The saving in vertical space would, for example, allow for a fifth row of EPG to be displayed on the 42" television if 800 pixels of height were reserved for EPG row display.

With reference to Figure 4 an alternative method of determining display size information from information received from the television set 200, when that information does not include display size information itself, can be used in some embodiments. At step 402, information received from the television set 200, for example in EDID format, is analysed to identify the model or identity of the television set, for example using manufacturer, model and/or serial number information contained in the EDID signal. Using one or more of manufacturer, model and serial number information, or type model information derived therefrom, a device databases is accessed at step 404 to look up display size information for the television in question.

The database may be local to the set-top box 100 or may be accessed using the communication interface 104, for example over the Internet. In some embodiments, the database access may involve accessing a web search engine and searching for display size information in webpages on the World Wide Web. Once information about the television set 200 in question has been located, display size information is determined for the television set 200 at step 406. That information may be used on the fly or stored for later use, as described above.

Returning to Figure 3, in some embodiments, the viewing distance (or information relating to it), that is the distance at which a user of the interactive application views the display 202 of the television set 200, is determined at step 310 and step 306 of setting layout parameter(s) of the interactive application sets these parameters as a function of both determined logical pixel density and the determined viewing distance or viewing distance information. While the amount of information that can be displayed on the display screens of the interactive application increases with the logical pixel density as discussed above, it will decrease with the viewing distance. Therefore, the parameters may be adjusted such that the amount of information displayed increases with logical pixel density and decreases with viewing distance. For example, the parameters may be set such that font size increases with viewing distance and decreases with the determined logical pixel density. Some or all of the same parameters discussed above in relation to step 306 may be adjusted based on both logical pixel density and viewing distance. In some embodiments some parameters are adjusted based on both logical pixel density and viewing distance and some are adjusted based on one of these. In some embodiments, some of the parameters are adjusted based on viewing distance and others based on logical pixel density.

The display layout parameters of the interactive application may be adjusted in numerous ways in line with the above considerations but the following table provides an example of how the distance and/or logical pixel density may be taken into account in adjusting display parameters, with a "+" indicating a direct relationship, that is the parameter increases with increasing logical pixel density or viewing distance and a "-" indicates an inverse relationship, that is the parameter decreases with increasing logical pixel density or viewing distance.

Layout Parameter Logical Pixel Density Viewing Distance

Font Size - +

Rows In List + -

Rows/Columns In Grid + -

Time Scale in Grid Guide - +

PIP Window Size - + Some of these parameters are particularly relevant to EPG interactive applications but it will be appreciated that they are applicable to any interactive application displaying relevant elements.

Viewing distance (or viewing distance information) may be determined at step 310 in a number of ways. In some embodiments, the viewing distance is a parameter a user can set, for example during a setup procedure after set-top box. In some embodiments, the user can set the viewing distance on the fly, for example using a remote control, for example by entering a value for the viewing distance or by increasing or decreasing viewing distance using directional keys on the remote control as and when needed. In other embodiments, viewing distance (information) is derived from sensor signals. With reference to Figure 4, a number of possible sensor configurations are described.

In some embodiments, the set-top box 100 comprises a viewing distance sensor 1 14, dedicated to sensing viewing distance. The viewing distance sensor 1 14 may for example be an ultrasound sensor for sensing the distance to any nearest object in front of the set- top box 100 using the travel time of ultrasound reflections. The viewing distance sensor 1 14 is connected to the processor 106 provide the processor 106 with a viewing distance signal or a signal from which viewing distance can be derived for use at step 310. In some embodiments, alternatively or additionally, viewing distance is determined using sensors on the television set 200. In some embodiments, a microphone 206 on the television set 200 is used to receive sound reflections of sounds generated by television set speakers under control of the processor 106. The sound reflections signals received by the microphone 206 are communicated to the processor 106, which is configured to determine viewing distance information based on echolocation techniques, for example based on reflection travel times or a frequency space analysis of the reflected sounds. In some embodiments, a camera, for example a web cam 208 on the television set 200 is used to derive the distance information.

In such embodiments, the processor 106 receives images from the web cam 208 and applies a face detection algorithm to detect faces in the images. Based on the image size of the detected faces, optical characteristics of the web cam and typical face sizes, the processor 106 determines viewing distance as a quantity inversely proportional to the detected face size. For example, in some embodiments, the web cam 208 (or other integrated camera) has a fixed (e.g. in the bezel of the television set 200) or known position and the lens and sensor parameters of the camera are fixed or known. The face detection algorithm, in some embodiments, determines a bounding box for faces in the captured image and from the position of the camera, the lens and sensor parameters and the size of the bounding box a distance of the detected face from the camera is estimated using optical geometry, as is well known.

It will, of course, be understood that the processing described above in connection with the processor 106 to derive viewing distance information may also be carried out elsewhere, for example the television 200 may have a viewing distance determination module for determining viewing distance from the microphone 206 or web cam 208 and the television 200 may provide pre-computed viewing distance signals to the set-top box 100. Further, while a number of embodiments using different sources of information and signals for determining viewing distance has been described above, it will be appreciated that these sources and signals can be combined to determine viewing distance. Further, it will be appreciated that any viewing distance signal or information used in the methods described above need not actually be a viewing distance in terms of an actual distance of a viewer from the display screen as long as the signal or information is sufficiently related to viewing distance to enable the layout parameters to be set.

The following embodiments are also disclosed:

1. A device for generating a display of an interactive television application, the device comprising:

a memory for storing an interactive application and one or more display layout parameters of the interactive application;

a processor configured to:

determine display size information for a display device; determine pixel density information for the display of the interactive application on the display device using resolution information for the interactive application and the display size information;

set the one or more display layout parameters of the interactive application in dependence on the pixel density information;

cause the display of the interactive application on the display device.

2. A device according to item 1 , wherein the resolution information comprises logical resolution information and determining the pixel density comprises determining a logical pixel density.

3. A device according to item 2, wherein the resolution information comprises logical resolution information and physical resolution information and determining the pixel density comprises determining the logical pixel density based on the logical and physical resolution information and the display size information, preferably using the lower resolution one of the logical and physical resolution information and the display size information.

4. A device according to any one of items 1 to 3, the processor being configured to set the one or more display layout parameters of the interactive application in dependence upon the pixel density information and viewing distance information related to viewing distance of a user from the display device.

5. A device according to item 4, the process or being configured to determine viewing distance information using information received from a sensor.

6. A device according to any one of items 1 to 5, wherein the layout parameters comprise one or more of: font size; rows in a list; rows and/or columns in a grid; time scale of a grid guide; size of a PIP window.

7. A device according to any one of items 1 to 6, wherein in the interactive television application is an interactive television guide.

8. A device according to anyone of items 1 to 7, wherein the device is a set-top box and the display device is a television set. 9. A device according to any one of items 1 to 8, the processor being configured to determine display size information using information obtained from the display device

10. A device according to item 9, wherein the information obtained from the display device identifies a type, make and/or model of the display device and determining display size information includes looking up the type, make and/or model in a database.

Having read the above specific description of some embodiments, it will be apparent to the person skilled in the art that many variations, modifications and juxtapositions of the embodiments and features described above are possible and will fall within the scope of the appended claims. In particular, while the above description has been made in terms of a set-top box connected to a television set, it will be appreciated that other devices, such as computers, portable or otherwise, mobile phones, tablets, etc may be used to implement the respective functions of the set-top box and television set. Further, the disclosure is not limited to implementations using separate devices but the functions of the set-top box and television set described above may equally be implemented in an integrated device, for example a smart TV set. In embodiments where separate devices are used, connection between the devices may be by cable, for example a HDMI cable, or a coaxial cable for frequency modulated signals, or by a wireless connection, for example by a wireless router or wireless dongle of a smart TV. Other connections between devices, such as USB, ethernet or any other type of connection are equally envisaged.