GB2515353A

GB2515353A - Head-mountable apparatus and systems

Info

Publication number: GB2515353A
Application number: GB1314980.2A
Authority: GB
Inventors: Simon John Hall; Simon Mark Benson
Original assignee: Sony Computer Entertainment Europe Ltd
Current assignee: Sony Interactive Entertainment Europe Ltd
Priority date: 2013-06-11
Filing date: 2013-08-21
Publication date: 2014-12-24
Also published as: GB201314980D0; GB201310374D0

Abstract

A cohort or group of devices D1, D2, D3, 800 in which at least two devices are operable to detect the position of another device of the group, and at least one base device of the group 800 is arranged to receive detected position data from other devices within the group in order to generate consolidated position data relating to devices in the set. One or more of the devices D1-D3 may be a head mounted display (HMD. The HMD may render and display a virtual version of another device based on the detected position of that device. The devices may be part of a gaming system, which may include a game console 300 as the base device, HMD 20 and hand-held controller 330. The HMD may include a video display (not shown) for displaying game images to the user 10, and a video camera 122 for relaying images to the game console 300. Other devices within the group may include mobile telephones (not shown), loudspeakers (not shown), or gaming peripherals such as steering wheel controllers (not shown) or bats/racquets (not shown).

Description

HEAD-MOUNTABLE APPARATUS AND SYSTEMS

This invention relates to head-mountable apparatus and systems.

A head-mountable display (HMD) is one example of a head-mountable apparatus.

Audio headphones comprising a frame supporting one or more audio transducers are another example of a head-mountable apparatus. A head-mounted torch or light is a further example of a head-mountable apparatus. The following background discussions will relate mainly to HMDs, but the principles are also applicable to other types of head-mountable apparatus.

In an HMD, an image or video display device is provided which may be worn on the head or as part of a helmet. Either one eye or both eyes are provided with small electronic display devices.

Some HMDs allow a displayed image to be superimposed on a real-world view. This type of HMD can be referred to as an optical see-through HMD and generally requires the display devices to be positioned somewhere other than directly in front of the user's eyes.

Some way of deflecting the displayed image so that the user may see it is then required. This might be through the use of a partially reflective mirror placed in front of the user's eyes so as to allow the user to see through the mirror but also to see a reflection of the output of the display devices. In another arrangement, disclosed in EP-A-1 731 943 and US-A-2010/0157433, a waveguide arrangement employing total internal reflection is used to convey a displayed image from a display device disposed to the side of the user's head so that the user may see the displayed image but still see a view of the real world through the waveguide. Once again, in either of these types of arrangement, a virtual image of the display is created (using known techniques) so that the user sees the virtual image at an appropriate size and distance to allow relaxed viewing. For example, even though the physical display device may be tiny (for example, 10 mm x 10 mm) and may be just a few millimetres from the user's eye, the virtual image may be arranged so as to be perceived by the user at a distance of (for example) 20 m from the user, having a perceived size of 5 m x Sm.

Other HMDs, however, allow the user only to see the displayed images, which is to say that they obscure the real world environment surrounding the user. This type of HMD can position the actual display devices in front of the user's eyes, in association with appropriate lenses or other optical components which place a virtual displayed image at a suitable distance for the user to focus in a relaxed manner -for example, at a similar virtual distance and perceived size as the optical see-through HMD described above. This type of device might be used for viewing movies or similar recorded content, or for viewing so-called virtual reality content representing a virtual space surrounding the user. It is of course however possible to display a real-world view on this type of HMD, for example by using a forward-facing camera to generate images for display on the display devices.

Although the original development of HMDs was perhaps driven by the military and professional applications of these devices, HMDs are becoming more popular for use by casual users in, for example, computer game or domestic computing applications.

Various aspects and features of the present invention are defined in the appended claims and within the text of the accompanying description and include at least a head mountable apparatus such as a display and a method of operating a head-mountable apparatus as well as a computer program.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 schematically illustrates an HMD worn by a user; Figure 2 is a schematic plan view of an HMD; Figure 3 schematically illustrates the formation of a virtual image by an HMD; Figure 4 schematically illustrates another type of display for use in an HMD; Figure 5 schematically illustrates a pair of stereoscopic images; Figures 6 and 7 schematically illustrate a user wearing an HMD connected to a Sony® PlayStation 3® games console; Figure 8 schematically illustrates a change of view of user of an HMD; Figures 9a and 9b schematically illustrate HMDs with motion sensing; Figure 10 schematically illustrates a position sensor based on optical flow detection; Figure 11 schematically illustrates the generation of images in response to HMD position or motion detection; Figure 12 schematically illustrates part of the functionality of an HMD for detecting the position of another HMD or a peripheral device; Figure 13 schematically illustrates part of the functionality of a peripheral device for detecting the position of another device; Figure 14 schematically illustrates a cohort of devices; Figure 15 schematically illustrates pad of the operation of a device; Figure 16 schematically illustrates part of the operation of a device; and Figure 17 schematically illustrates the relative positions of a cohort of devices as detected by each device.

Referring now to Figure 1, a user 10 is wearing an HMD 20 (as an example of a generic head-mountable apparatus -other examples including, where the technical context allows, audio headphones or a head-mountable light source) on the user's head 30. The HMD comprises a frame 40, in this example formed of a rear strap and a top strap, and a display portion 50.

Note that the HMD of Figure 1 may comprise further features, to be described below in connection with other drawings, but which are not shown in Figure 1 for clarity of this initial explanation.

The HMD of Figure 1 completely (or at least substantially completely) obscures the user's view of the surrounding environment. All that the user can see is the pair of images displayed within the HMD.

The HMD has associated headphone audio transducers or earpieces 60 which fit into the user's left and right ears 70. The earpieces 60 replay an audio signal provided from an external source, which may be the same as the video signal source which provides the video signal for display to the user's eyes.

The combination of the fact that the user can see only what is displayed by the HMD and, subject to the limitations of the noise blocking or active cancellation properties of the earpieces and associated electronics, can hear only what is provided via the earpieces, mean that this HMD may be considered as a so-called "full immersion" HMD. Note however that in some embodiments the HMD is not a full immersion HMD, and may provide at least some facility for the user to see and/or hear the user's surroundings. This could be by providing some degree of transparency or partial transparency in the display arrangements, and/or by projecting a view of the outside (captured using a camera, for example a camera mounted on the HMD) via the HMD's displays, and/or by allowing the transmission of ambient sound past the earpieces and/or by providing a microphone to generate an input sound signal (for transmission to the earpieces) dependent upon the ambient sound.

A front-facing camera 122 may capture images to the front of the HMD, in use. A Bluetooth® antenna 124 may provide communication facilities or may simply be arranged as a directional antenna to allow a detection of the direction of a nearby Bluetooth transmitter.

In operation, a video signal is provided for display by the HMD. This could be provided by an external video signal source 80 such as a video games machine or data processing apparatus (such as a personal computer), in which case the signals could be transmitted to the HMD by a wired or a wireless connection 82. Examples of suitable wireless connections include Bluetooth® connections. Audio signals for the earpieces 60 can be carried by the same connection. Similarly, any control signals passed from the HMD to the video (audio) signal source may be carried by the same connection. Furthermore, a power supply 83 (including one or more batteries and/or being connectable to a mains power outlet) may be linked by a cable 84 to the HMD. Note that the power supply 83 and the video signal source 80 may be separate units or may be embodied as the same physical unit. There may be separate cables for power and video (and indeed for audio) signal supply, or these may be combined for carriage on a single cable (for example, using separate conductors, as in a USB cable, or in a similar way to a "power over Ethernet" arrangement in which data is carried as a balanced signal and power as direct current, over the same collection of physical wires). The video and/or audio signal may be carried by, for example, an optical fibre cable. In other embodiments, at least part of the functionality associated with generating image and/or audio signals for presentation to the user may be carried out by circuitry and/or processing forming part of the HMD itself A power supply may be provided as part of the HMD itself.

Some embodiments of the invention are applicable to an HMD having at least one electrical and/or optical cable linking the HMD to another device, such as a power supply and/or a video (and/or audio) signal source. So, embodiments of the invention can include, for

example:

(a) an HMD having its own power supply (as part of the HMD arrangement) but a cabled connection to a video and/or audio signal source; (b) an HMD having a cabled connection to a power supply and to a video and/or audio signal source, embodied as a single physical cable or more than one physical cable; (c) an HMD having its own video and/or audio signal source (as pad of the HMD arrangement) and a cabled connection to a power supply; or (d) an HMD having a wireless connection to a video and/or audio signal source and a cabled connection to a power supply.

If one or more cables are used, the physical position at which the cable 82 and/or 84 enters or joins the HMD is not particularly important from a technical point of view. Aesthetically, and to avoid the cable(s) brushing the user's face in operation, it would normally be the case that the cable(s) would enter or join the HMD at the side or back of the HMD (relative to the orientation of the user's head when worn in normal operation). Accordingly, the position of the cables 82, 84 relative to the HMD in Figure 1 should be treated merely as a schematic representation.

Accordingly, the arrangement of Figure 1 provides an example of a head-mountable display system comprising a frame to be mounted onto an observer's head, the frame defining one or two eye display positions which, in use, are positioned in front of a respective eye of the observer and a display element mounted with respect to each of the eye display positions, the display element providing a virtual image of a video display of a video signal from a video signal source to that eye of the observer.

Figure 1 shows just one example of an HMD. Other formats are possible: for example an HMD could use a frame more similar to that associated with conventional eyeglasses, namely a substantially horizontal leg extending back from the display portion to the top rear of the user's ear, possibly curling down behind the ear. In other (not full immersion) examples, the user's view of the external environment may not in fact be entirely obscured; the displayed images could be arranged so as to be superposed (from the user's point of view) over the external environment. An example of such an arrangement will be described below with reference to Figure 4.

In the example of Figure 1, a separate respective display is provided for each of the user's eyes. A schematic plan view of how this is achieved is provided as Figure 2, which illustrates the positions 100 of the user's eyes and the relative position 110 of the user's nose.

The display portion 50, in schematic form, comprises an exterior shield 120 to mask ambient light from the user's eyes and an internal shield 130 which prevents one eye from seeing the display intended for the other eye. The combination of the user's face, the exterior shield 120 and the interior shield 130 form two compartments 140, one for each eye. In each of the compartments there is provided a display element 150 and one or more optical elements 160.

The way in which the display element and the optical element(s) cooperate to provide a display to the user will be described with reference to Figure 3.

Referring to Figure 3, the display element 150 generates a displayed image which is (in this example) refracted by the optical elements 160 (shown schematically as a convex lens but which could include compound lenses or other elements) so as to generate a virtual image 170 which appears to the user to be larger than and significantly further away than the real image generated by the display element 150. As an example, the virtual image may have an apparent image size (image diagonal) of more than 1 m and may be disposed at a distance of more than 1 m from the user's eye (or from the frame of the HMD). In general terms, depending on the purpose of the HMD, it is desirable to have the virtual image disposed a significant distance from the user. For example, if the HMD is for viewing movies or the like, it is desirable that the user's eyes are relaxed during such viewing, which requires a distance (to the virtual image) of at least several metres. In Figure 3, solid lines (such as the line 180) are used to denote real optical rays, whereas broken lines (such as the line 190) are used to denote virtual rays.

An alternative arrangement is shown in Figure 4. This arrangement may be used where it is desired that the user's view of the external environment is not entirely obscured. However, it is also applicable to HMD5 in which the user's external view is wholly obscured. In the arrangement of Figure 4, the display element 150 and optical elements 200 cooperate to provide an image which is projected onto a mirror 210, which deflects the image towards the user's eye position 220. The user perceives a virtual image to be located at a position 230 which is in front of the user and at a suitable distance from the user.

In the case of an HMD in which the user's view of the external surroundings is entirely obscured, the mirror 210 can be a substantially 100% reflective mirror. The arrangement of Figure 4 then has the advantage that the display element and optical elements can be located closer to the centre of gravity of the user's head and to the side of the user's eyes, which can produce a less bulky HMD for the user to wear. Alternatively, if the HMD is designed not to completely obscure the user's view of the external environment, the mirror 210 can be made partially reflective so that the user sees the external environment, through the mirror 210, with the virtual image superposed over the real external environment.

In the case where separate respective displays are provided for each of the user's eyes, it is possible to display stereoscopic images. An example of a pair of stereoscopic images for display to the left and right eyes is shown in Figure 5. The images exhibit a lateral displacement relative to one another, with the displacement of image features depending upon the (real or simulated) lateral separation of the cameras by which the images were captured, the angular convergence of the cameras and the (real or simulated) distance of each image feature from the camera position.

Note that the lateral displacements in Figure 5 could in fact be the other way round, which is to say that the left eye image as drawn could in fact be the right eye image, and the right eye image as drawn could in fact be the left eye image. This is because some stereoscopic displays tend to shift objects to the right in the right eye image and to the left in the left eye image, so as to simulate the idea that the user is looking through a stereoscopic window onto the scene beyond. However, some HMDs use the arrangement shown in Figure 5 because this gives the impression to the user that the user is viewing the scene through a pair of binoculars. The choice between these two arrangements is at the discretion of the system designer.

In some situations, an HMD may be used simply to view movies and the like. In this case, there is no change required to the apparent viewpoint of the displayed images as the user turns the user's head, for example from side to side. In other uses, however, such as those associated with virtual reality (VR) or augmented reality (AR) systems, the user's viewpoint needs to track movements with respect to a real or virtual space in which the user is located.

Figure 6 schematically illustrates a user wearing an HMD connected to a Sony® Playstation 3® games console 300 as an example of a base device. The games console 300 is connected to a mains power supply 310 and (optionally) to a main display screen (not shown).

A cable, acting as the cables 82, 84 discussed above (and so acting as both power supply and signal cables), links the HMD 20 to the games console 300 and is, for example, plugged into a USB socket 320 on the console 300. Note that in the present embodiments, a single physical cable is provided which fulfils the functions of the cables 82, 84. In Figure 6, the user is also shown holding a hand-held controller 330 which may be, for example, a Sony® Move® controller which communicates wirelessly with the games console 300 to control (or to contribute to the control of) game operations relating to a currently executed game program.

The video displays in the HMD 20 are arranged to display images generated by the games console 300, and the earpieces 60 in the HMD 20 are arranged to reproduce audio signals generated by the games console 300. Note that if a USB type cable is used, these signals will be in digital form when they reach the HMD 20, such that the HMD 20 comprises a digital to analogue converter (DAC) to convert at least the audio signals back into an analogue form for reproduction.

Images from the camera 122 mounted on the HMD 20 are passed back to the games console 300 via the cable 82, 84. Similarly, if motion or other sensors are provided at the HMD 20, signals from those sensors may be at least partially processed at the HMD 20 and/or may be at least partially processed at the games console 300. The use and processing of such signals will be described further below.

The USB connection from the games console 300 also provides power to the HMD 20, according to the USB standard.

Figure 7 schematically illustrates a similar arrangement in which the games console is connected (by a wired or wireless link) to a so-called "break out box" acting as a base or intermediate device 350, to which the HMD 20 is connected by a cabled link 82,84. The breakout box has various functions in this regard. One function is to provide a location, near to the user, for some user controls relating to the operation of the HMD, such as (for example) one or more of a power control, a brightness control, an input source selector, a volume control and the like. Another function is to provide a local power supply for the HMD (if one is needed according to the embodiment being discussed). Another function is to provide a local cable anchoring point. In this last function, it is not envisaged that the break-out box 350 is fixed to the ground or to a piece of furniture, but rather than having a very long trailing cable from the games console 300, the break-out box provides a locally weighted point so that the cable 82, 84 linking the HMD 20 to the break-out box will tend to move around the position of the break-out box. This can improve user safety and comfort by avoiding the use of very long trailing cables.

It will be appreciated that the localisation of processing in the various techniques described in this application can be varied without changing the overall effect, given that an HMD may form part of a set, group or (more generally) a cohort of interconnected devices (that is to say, interconnected for the purposes of data or signal transfer, but not necessarily connected by a physical cable). So, processing which is described as taking place "at" one device, such as at the HMD, could be devolved to another device such as the games console (base device) or the break-out box. Processing tasks can be shared amongst devices. Source signals, on which the processing is to take place, could be distributed to another device, or the processing results from the processing of those source signals could be sent to another device, as required. So any references to processing taking place at a particular device should be understood in this context. Similarly, where an interaction between two devices is basically symmetrical, for example where a camera or sensor on one device detects a signal or feature of the other device, it will be understood that unless the context prohibits this, the two devices could be interchanged without any loss of functionality.

As mentioned above, in some uses of the HMD, such as those associated with virtual reality (VR) or augmented reality (AR) systems, the user's viewpoint needs to track movements with respect to a real or virtual space in which the user is located.

This tracking is carried out by detecting motion of the HMD and varying the apparent viewpoint of the displayed images so that the apparent viewpoint tracks the motion.

Figure 8 schematically illustrates the effect of a user head movement in a VS or AR system.

Referring to Figure 8, a virtual environment is represented by a (virtual) spherical shell 250 around a user. Because of the need to represent this arrangement on a two-dimensional paper drawing, the shell is represented by a part of a circle, at a distance from the user equivalent to the separation of the displayed virtual image from the user. A user is initially at a first position 260 and is directed towards a portion 270 of the virtual environment. It is this portion 270 which is represented in the images displayed on the display elements 150 of the user's HMD.

Consider the situation in which the user then moves his head to a new position and/or orientation 280. In order to maintain the correct sense of the virtual reality or augmented reality display, the displayed portion of the virtual environment also moves so that, at the end of the movement, a new portion 290 is displayed by the HMD.

So, in this arrangement, the apparent viewpoint within the virtual environment moves with the head movement. If the head rotates to the right side, for example, as shown in Figure 8, the apparent viewpoint also moves to the right from the user's point of view. If the situation is considered from the aspect of a displayed object, such as a displayed object 300. this will effectively move in the opposite direction to the head movement. So, if the head movement is to the right, the apparent viewpoint moves to the right but an object such as the displayed object 300 which is stationary in the virtual environment will move towards the left of the displayed image and eventually will disappear off the left-hand side of the displayed image, for the simple reason that the displayed portion of the virtual environment has moved to the right whereas the displayed object 300 has not moved in the virtual environment.

Figures 9a and 9b schematically illustrated HMDs with motion sensing. The two drawings are in a similar format to that shown in Figure 2. That is to say, the drawings are schematic plan views of an HMD, in which the display element 150 and optical elements 160 are represented by a simple box shape. Many features of Figure 2 are not shown, for clarity of the diagrams. Both drawings show examples of HMDs with a motion detector for detecting motion of the observer's head.

In Figure 9a, a forward-facing camera 322 is provided on the front of the HMD. This may be the same camera as the camera 122 discussed above, or may be an additional camera.

This does not necessarily provide images for display to the user (although it could do so in an augmented reality arrangement). Instead, its primary purpose in the present embodiments is to allow motion sensing. A technique for using images captured by the camera 322 for motion sensing will be described below in connection with Figure 10. In these arrangements, the motion detector comprises a camera mounted so as to move with the frame; and an image comparator operable to compare successive images captured by the camera so as to detect inter-image motion.

Figure 9b makes use of a hardware motion detector 332. This can be mounted anywhere within or on the HMD. Examples of suitable hardware motion detectors are piezoelectric accelerometers or optical fibre gyroscopes. It will of course be appreciated that both hardware motion detection and camera-based motion detection can be used in the same device, in which case one sensing arrangement could be used as a backup when the other one is unavailable, or one sensing arrangement (such as the camera) could provide data for changing the apparent viewpoint of the displayed images, whereas the other (such as an accelerometer) could provide data for image stabilisation.

Figure 10 schematically illustrates one example of motion detection using the camera 322 of Figure Qa.

The camera 322 is a video camera, capturing images at an image capture rate of, for example, 25 images per second. As each image is captured, it is passed to an image store 400 for storage and is also compared, by an image comparator 410, with a preceding image retrieved from the image store. The comparison uses known block matching techniques (so-called "optical flow" detection) to establish whether substantially the whole image has moved since the time at which the preceding image was captured. Localised motion might indicate moving objects within the field of view of the camera 322, but global motion of substantially the whole image would tend to indicate motion of the camera rather than of individual features in the captured scene, and in the present case because the camera is mounted on the HMD, motion of the camera corresponds to motion of the HMD and in turn to motion of the user's head.

The displacement between one image and the next, as detected by the image comparator 410, is converted to a signal indicative of motion by a motion detector 420. If required, the motion signal is converted by to a position signal by an integrator 430.

As mentioned above, as an alternative to, or in addition to, the detection of motion by detecting inter-image motion between images captured by a video camera associated with the HMD, the HMD can detect head motion using a mechanical or solid state detector 332 such as an accelerometer. This can in fact give a faster response in respect of the indication of motion, given that the response time of the video-based system is at best the reciprocal of the image capture rate. In some instances, therefore, the detector 332 can be better suited for use with higher frequency motion detection. However! in other instances, for example if a high image rate camera is used (such as a 200 Hz capture rate camera), a camera-based system may be more appropriate. In terms of Figure 10, the detector 332 could take the place of the camera 322, the image store 400 and the comparator 410, so as to provide an input directly to the motion detector 420. Or the detector 332 could take the place of the motion detector 420 as well, directly providing an output signal indicative of physical motion.

Other position or motion detecting techniques are of course possible. For example, a mechanical arrangement by which the HMD is linked by a moveable pantograph arm to a fixed point (for example, on a data processing device or on a piece of furniture) may be used, with position and orientation sensors detecting changes in the deflection of the pantograph arm. In other embodiments, a system of one or more transmitters and receivers, mounted on the HMD and on a fixed point, can be used to allow detection of the position and orientation of the HMD by triangulation techniques. For example, the HMD could carry one or more directional transmitters, and an array of receivers associated with known or fixed points could detect the relative signals from the one or more transmitters. Or the transmitters could be fixed and the receivers could be on the HMD. Examples of transmitters and receivers include infra-red transducers, ultrasonic transducers and radio frequency transducers. The radio frequency transducers could have a dual purpose, in that they could also form part ot a radio frequency data link to and/or from the HMD, such as a Bluetooth® link.

Figure 11 schematically illustrates image processing carried out in response to a detected position or change in position of the HMD.

As mentioned above in connection with Figure 10, in some applications such as virtual reality and augmented reality arrangements, the apparent viewpoint of the video being displayed to the user of the HMD is changed in response to a change in actual position or orientation of the user's head.

With reference to Figure 11, this is achieved by a motion sensor 450 (such as the arrangement of Figure 10 and/or the motion detector 332 of Figure 9b) supplying data indicative of motion and/or current position to a required image position detector 460, which translates the actual position of the HMD into data defining the required image for display. An image generator 480 accesses image data stored in an image store 470 if required, and generates the required images from the appropriate viewpoint for display by the HMD. The external video signal source can provide the functionality of the image generator 480 and act as a controller to compensate for the lower frequency component of motion of the observer's head by changing the viewpoint of the displayed image so as to move the displayed image in the opposite direction to that of the detected motion so as to change the apparent viewpoint of the observer in the direction of the detected motion.

The examples to be discussed below relate to interactions of "devices". In this context, a device may be: an HMD, a break-out box, a games console or other base device, a peripheral device or the like. Two or more of the devices are capable (by means of optical, camera based, detection, radio frequency detection, audio detection or other detection techniques) of detecting and/or tracking the position (or at least an aspect of the relative position) of another device. The aspect of the relative position may be the distance, the angle or the like. Together the set of such devices will be referred to as a cohort of devices.

In the case of an HMD as an example of such a device, in some embodiments the HMD may detect at least aspects of the position or relative position of another device by using the forward facing camera 122 or 322.

An example of a peripheral device is a steering wheel for use by the user in playing (for example) a driving game or the like, but many other such devices may be considered, such as a weapon, a bat or racquet, a gearstick, a handlebar and the like. The steering wheel may have electronic sensors to detect its rotational position, with that information being transmitted back to the HMD, the break-out box or the games console as telemetry data. The transmitted rotational position can then be used as part of the controls of the game functionality.

Another aspect of significance to many interactive computing environments, an example being a computer game environment, is a perceived need to detect the spatial (physical) position of each of a cohort of devices. In some examples, this can provide a data on which the progress of the interactive computing activity (for example, the progress of the computer game) may be based. With particular relevance to the present discussion of HMD technology, a detection of the relative position of one device, as considered from the position of the HMD, can allow a virtual version of that device to be rendered at the appropriate image position as presented to the viewer or wearer of the HMD. This relative position can be obtained either by a direct detection of the relative position by the HMD (or indeed by the device), or can be derived from detected information indicative of the absolute positions of the HMD and the device, along with the current orientation of the HMD.

In the discussion which follows, functionality of various devices will be considered. It should be noted that within the cohort of devices forming an interactive computing environment of this type, the processing tasks to be described below may be carried out by various different devices within the cohort. As a particular example, processing tasks associated with a peripheral device or with an HMD may in fact be carried out by a processor which is located at a games console or a break-out box, for example. One reason for doing this is to allow for lighter weight, lower cost and lower power consumption by user-operable or user-wearable devices, while concentrating the processing resources in a device such as a games console, which may use the a mains power supply and which would generally be expected to remain stationary during the gaming experience (so that weight is not an issue for such a device). Accordingly, where particular functions are described below as being carried out by certain devices, it will be understood that those processing tasks may in fact be devolved to other devices or even to remote processing resource such as cloud-based processing resource.

One possibility for detecting the positions of a cohort of devices is to entrust one single device with the detection. An example here would be to provide a games console with one or more cameras by which the games console can detect and track the positions of multiple devices within view of the cameras. A different approach will be described below.

Figure 12 schematically illustrates pad of the functionality of an HMD for detecting the position of another HMD or a peripheral device.

The HMD comprises a forward-facing camera 122/322 as discussed above, and this camera is, in the present arrangement, viewing a peripheral control device 600 disposed in front of the user Images captured by the camera 122/322 are supplied to a detector 610 and an image processor 620. These devices share the functionality of deriving detail from the image in the manner discussed above. In one example, the detector 610 is operable to detect the general location of the peripheral device by shape matching and/or detecting markers or illuminations associated with the device, and the image processor 620 may be operable to detect movements of the device and occlusions of it.

The image processor 620 passes information to a renderer 630 which generates a virtual version of the peripheral for display to the user. Note that although this would normally be a virtual representation of the same type of control device as the physical control, this need not be the case. So, the peripheral could be a simple hand-held structure similar perhaps to the Sony® PlayStation ® Move TM controller, but the rendered image could take on various different shapes such as a bat, racquet, weapon and the like, rendered at the detected position of the peripheral.

The renderer 630 can optionally be operable to render additional features such as a hand and arm at the position of a detected occlusion of the peripheral 600.

The arrangements discussed above assume that the camera is provided as part of the HMD. Figure 13 schematically illustrates part of the functionality of a hand held peripheral device 700 which makes use of a camera 710 associated with the handheld peripheral device.

Note that the peripheral device may be a specific gaming device such as a steering wheel control or a hand-held game controller such as the Sony Six-axis ® controller, or may be, for example, a generic device such as a mobile telephone.

In operation, the camera 710 of the peripheral device captures images of the HMD, assuming the peripheral device is held by the user in front of the HMD, and either processes those images itself or (as shown in Figure 13) passes data relating to those images by telemetry (for example, wireless telemetry) to a processor 720 associated with the HMD. The processor 720 detects the position of the peripheral device 700 with respect to the HMD and passes data to a renderer 730 which renders a virtual version of the peripheral device at the appropriate position according to the data received from the processor 720.

Note that the arrangement shown in Figure 13 can also be used in order for the relative position of the HMD and the break-out box to be established, but in this instance, the camera 710 would be the HMD camera or a camera associated with the break-out box, and the presence in a captured image of the other of the HMD and the break-out box is detected.

Note that if multiple peripheral devices are present, each device could detect the relative position of one or more other devices (including the HMD within the cohort of devices).

Note that many mobile telephones have at least two cameras and are normally held close to a player, so that the position of the mobile telephone gives a useful indication of the position of a player. One camera can provide a view of the player and the other camera can operate according to the position detection algorithms discussed here. Alternatively, both cameras can provide position detection information, looking in both directions with respect to the mobile telephone. A PS Vita ® mobile gaming device also has a camera.

The techniques discussed here can operate in conjunction with other position detection or mapping techniques such as the so-called SLAM technique. One or more of the camera-equipped devices can use SLAM to develop a map of the environment, and send the relative positions of pairs of devices can be used to derive positions of other devices within that map.

Some examples of the SLAM technique rely on translation of the camera capturing the images, and this can be particularly relevant to the usei walking towards, for example, a hazard. In many instances, if the user stay still, the user is not likely to interact with a hazard such as a piece of furniture. But when the user is moving, these dangers are present. However, the movement of the user actually allows a SLAM operation to be carried out by the HMD camera and associated processor which in turn can allow the detection of the 3-D position of each hazard.

Some embodiments use a base stations such as a Sony PlayStation device and associated camera, in which case (in some examples) a portable device can be located by the PlayStation by, for example, the portable device emitting a sound which is detected by a microphone array at the base station. The sound may be an audible sound if the microphone array is arranged only to detect audible inputs. But in other embodiments the position detection is carried out collaboratively by the various portable or peripheral devices in the room environment.

Similar techniques can be used in respect of, for example, audio loudspeakers. In a surround sound system, it is useful for the system to vary the response of each loudspeaker according to the spatial position of that loudspeaker. Using the techniques discussed here, each loudspeaker can be equipped with a camera and/or other position detection systems, and these techniques can be used to derive, collaboratively, the relative positions of all of the loudspeakers.

Figure 14 schematically illustrates a cohort of devices, including a base device 800 and multiple other devices Dl, D2 and D3. An example of the base device 800 is a games console of the type described above. Another example of the base device 800 is a break-out box of the type described above. Examples of the other devices Dl... 03 include one or more HMD devices, one or more peripheral control devices, or one or more hand-held gaming devices (an example of such a hand-held device being a Sony® PS Vita ® device).

Note that an example interactive computer environment such as a gaming environment may include other devices for which the device position is of no interest. Indeed, in some examples, the actual position of the base device 800 may be of no relevance to the interactive computing operations, other than to serve as a base point from which other positions may be derived. The term "cohort" may therefore be considered to include all devices, such that at least two or more are (a) capable of detecting inter-device positions, and (b) interested (from the point of view of the processing carried out at that device) in the result. Alternatively, the term "cohort" may be taken to refer only to the two or more devices which meet these conditions, but noting that other devices may also be present.

Figure 14 illustrates communications between the base device 800 and the other devices by means of solid arrows 810. Direct communication on a peer to peer basis is also possible between the devices themselves, as shown by the dashed arrows 820. Note that the communication between the various devices shown in Figure 14 can be wired or wireless communication.

Figure 15 schematically illustrates part of the operation of a device. Here, the device can be any of the devices shown in Figure 14. The example device comprises a position detector 830 which is operable to detect the position, or at least an aspect of the relative position, of one or more of the other devices of the cohort. As discussed above, the detection can be by optical (such as camera-based) detection, radio4requency detection, audio detection or other detection techniques. The detection may be of the absolute position of the other device or the relative position of the other device. The position detector 830 passes information defining any detected aspects of the position of the other device to a data transmitter 840 which transmits data defining the detected position to one or more other devices in the cohort. As an example, in the case that the device in question is one of the movable devices Dl... D3, the data transmitter 840 may transmit the detected position of another device back to the base device 800. In another example, the data transmitter 840 may transmit the detected position data to all other devices or to a subset of the other devices.

Note that the position detector 830 may, in addition, detect the absolute position of the devices of which the position detector 830 forms a part. This absolute position data can also be transmitted by the data transmitter 840 to one or more other devices.

Figure 16 schematically illustrates part of the operation of a device of the cohort of Figure 14. Here, the operations as illustrated relate to the reception of position data as transmitted by another device.

A data receiver 850 is arranged to receive position data transmitted by one or more other devices in the cohort. A position detector 860 is operable to detect one or both of: the absolute position of that device, and the absolute or relative position (or aspects of it) of one or more other devices. A processor 870 combines the data as received by the data receiver 850 and the data generated by the position detector 860 to form a consolidated map of the positions of multiple ones of the cohort of devices. This process will be discussed in more detail with reference to Figure 17 below.

Note that an individual device may incorporate the functionality shown in both Figure 15 and Figure 16. In this case, the position detector is 830 and 860 may in fact be the same unit.

In some embodiments, the operations carried out by the processor 870 may take place in only one of the devices, such as at the base device 800. In such an arrangement, or indeed in other embodiments, the consolidated map of device positions as generated by the processor 870 can be supplied to a data transmitter (such as the data transmitter 840) for transmission to one or more other devices in the cohort.

In some embodiments, the operations of the processor 870 may be distributed among two or more devices in the cohort, such that an individual one of such devices does not generate a consolidated map of the entire cohort of devices, but rather of a subset of the devices, such that the consolidated maps generated by the two or more processors, 870 together form a consolidated map of the positions of all of the devices of interest.

Figure 17 schematically illustrates the relative positions of a cohort of devices as detected by each device. In Figure 17, the position of each device as drawn on the page is intended to refer to a representation of the actual physical position of that device, rather than (as shown in Figure 14) the logical connections between the devices. Accordingly, the dashed lines 900 in Figure 17 represent directions rather than data connections.

Considering first the base device 800, assume that (using one or more cameras, for example) the base device is able to detect at least the angular position 910, 911, 912 of the three devices Dl... D3. Then assume that each of the other devices Dl... D3 is capable (again, using one or more cameras) of detecting the angular position (not shown for clarity of Figure 17) of a least one of the other devices and of the base device 800. It is then a triangulation task using known translation techniques to derive the absolute position of each of the devices. Note that the absolute position is defined in terms of a coordinate system, for example a coordinate system having the base device 800 at its origin.

A similar arrangement can be achieved if only the inter-device distances are detectable, or if combinations of inter-device distances and inter-device angles are detectable.

Accordingly, embodiments of the invention can provide a cohort of devices in which at least two of the devices are operable to detect the position of another device of the cohort, at least one device within the cohort being arranged to receive the detected positions from other devices and to generate consolidated position data relating to devices in the cohort.

Here, the "position" may be an absolute position or may be at least an aspect (such as an inter-device angle andlor an inter-device separation) of a relative position. An "absolute" position can be expressed with respect to a coordinate system which may in turn be based upon the position of one of the devices such as a base device.

In embodiments of the invention, one or more of the devices of the cohort may be capable of detecting their own position and transmitting data defining that position to one or more other devices of the cohort.

One or more of the devices may be a head-mountable display (HMD). The HMD may be operable to render a virtual version of another device based on the detected position of that other device.

The detected position of one or more devices may be used as part of controlling operation of the cohort of devices, such as in an interactive computer gaming environment.

Examples of the devices of the cohort include an HMD, one or more peripheral or control devices, and optionally a base device such as a games console or break-out box.

Embodiments of the invention can also provide a device operable as one of the devices (such as one of the devices which generates consolidated position data) of a cohort according to any one of the preceding claims. For example, the device may be a loudspeaker or a mobile telephone.

Embodiments of the invention can also provide a method of operation of a cohort of devices in which at least two of the devices are operable to detect the position of another device of the cohort, the method comprising at least one device within the cohort receiving the detected positions from other devices and generating consolidated position data relating to devices in the cohort.

It will be appreciated that embodiments of the present invention may be implemented in hardware, programmable hardware, software-controlled data processing arrangements or combinations of these. It will also be appreciated that computer software or firmware used in such embodiments, and providing media for providing such software or firmware (such as storage media, for example a machine-readable non-transitory storage medium such as a magnetic or optical disc or a flash memory) are considered to represent embodiments of the present invention.

Claims

CLAIMS1. A cohort of devices in which at least two of the devices are operable to detect the position of another device of the cohort, at least one device within the cohort being arranged to receive the detected positions from other devices and to generate consolidated position data relating to devices in the cohort.
2. A cohort of devices according to claim 1, in which the position represents an absolute position.
3. A cohort of devices according to claim 2, in which the position is expressed with respect to a coordinate system which is in turn be based upon the position of one of the devices.
4. A cohort of devices according to claim 1, in which the position represents at least an aspect of a relative position.
5. A cohort of devices according to claim 4, in which the position represents an inter-device angle and/or an inter-device separation.
6. A cohort of devices according to one of the preceding claims, in which one or more of the devices of the cohort is operable to detect its own position and to transmit data defining that position to one or more other devices of the cohort.
7. A cohort of devices according to any one of the preceding claims, in which one or more of the devices is a head-mountable display (HMD).
8. A cohort of devices according to claim 7, in which the HMD is operable to render a virtual version of another device based on the detected position of that other device.
9. A cohort of devices according to any one of the preceding claims, in which the detected position of one or more devices is used as part of controlling operation of the cohort of devices.
10. A device operable as one of the devices of a cohort according to any one of the preceding claims.
11. A device according to claim 10, in which the device is a loudspeaker.
12. A device according to claim 10, in which the device is a mobile telephone.
13. A method of operation of a cohort of devices in which at least two of the devices are operable to detect the position of another device of the cohort, the method comprising at least one device within the cohort receiving the detected positions from other devices and generating consolidated position data relating to devices in the cohort.
14. Computer software which, when executed by a computer, causes the computer to carry out the method of claim 13.
15. A non-transitory machine-readable storage medium which stores computer software according to claim 14.