Method for displaying a stereoscopic content on an autostereoscopic display screen of which a part is observable by only one eye of a viewer

Abstract

The invention relates to a method for displaying stereoscopic content on an autostereoscopic display device comprising one or more autostereoscopic screens, wherein at least a part of these screens is observable by only one eye. In the method, it is determined which screen areas are out the field of view of the only one eye. The displaying of the stereoscopic content is then modified in such way that the pixels at the area that is out the field of view of the only one eye are instructed to provide the content for the other eye. This relieves the processor from the duty to constantly produce both left eye content and right eye content for the entire screen area. This has the advantage that processor capacity is saved, which may then be used for more important tasks such as achieving that the displayed stereoscopic image that is visible by both eyes is displayed in the desired quality. Another advantage is that crosstalk may be reduced by applying the method of the invention.

Description

[0001] METHOD FOR DISPLAYING A STEREOSCOPIC CONTENT ON AN AUTOSTEREOSCOPIC DISPLAY SCREEN OF WHICH A PART IS OBSERVABLE BY ONLY ONE EYE OF A VIEWER

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a method for displaying a stereoscopic content on an autostereoscopic display device. The invention further relates to an autostereoscopic display device configured to perform such method.

[0004] BACKGROUND

[0005] Autostereoscopic displays allow a viewer to perceive three-dimensional images of a three-dimensional environment without the need for a dedicated eyewear device such as a head set, a head-mounted display, glasses, etc. It is in particular possible to adapt the three-dimensional images to movement of the viewer relative to the display. For example, an object in the background may become invisible to a viewer due to motion parallax when an object on the foreground blocks the line of sight (occlusion).

[0006] Key to this technology is a display screen comprising a view-forming arrangement such as a lenticular lens or a parallax barrier, combined with an array of display pixel elements for producing a display output ( / .e. light). Such viewforming arrangement is capable of directing the display output to particular spatial directions, thereby allowing selective illumination of only one eye of a pair of eyes. By accurately controlling the display pixel elements individually, possibly with the aid of real-time obtained eye position data, the display screen can direct simultaneously a left eye image to a left eye of the viewer and a right eye image to a right eye of the viewer. The resulting stereoscopic image provides a depth perception to the viewer wherein elements in the image may appear in front of the display screen or behind the display screen.

[0007] The absence of any unnatural peripherals such as a head set, a head-mounted display, glasses, etc. allow a viewer to experience that he is physically present in the real world, while the autostereoscopic display forms a virtual window to another world - a truly believable virtual world that is also three- dimensional. Such experience of a viewer is often called an ‘immersive experience’.

[0008] There always exists a desire to improve an immersion in a virtual world. One way to achieve this is by increasing the display screen surface area that is available for the presentation of the stereoscopic images, for example by using autostereoscopic displays with larger screens or by using a plurality of autostereoscopic displays that are positioned around a viewer. A thus increased screen area however requires more processing capacity of a processor that renders the stereoscopic images, a capacity that is not always available. This may result in an impaired image display to the viewer, for example as a result of a bad eye tracking performance, low framerates, a poor input detection, more crosstalk, or a compromised resolution in case a dynamic resolution is implemented. This may make a viewer’s experience less immersive. Further, energy consumption usually increases with enlargement of the display screen area. The resulting local development of heat may be uncomfortable to the viewer and / or may require cooling.

[0009] SUMMARY OF THE INVENTION

[0010] It is therefore an object of the present invention to provide an autostereoscopic display device that achieves an increased immersion for a viewer in a virtual 3D-environment. A particular object is to provide a viewer with an enlarged view on a virtual 3D-environment, but without giving in to the quality of the displayed content and / or the viewer’s immersion in the virtual 3D-environment. It is also a particular object to reduce energy consumption and / or crosstalk of an autostereoscopic display device.

[0011] It has now been found that one or more of these objects can be reached by applying a particular displaying method wherein account is taken of areas of the display screen that are out of the field of view of only one eye of the viewer.

[0012] Accordingly, the present invention relates to a method for displaying a stereoscopic content on an autostereoscopic display device comprising one or more autostereoscopic display screens having a total screen area that is available for the display of stereoscopic content, the method comprising - providing the stereoscopic content, which comprises a left eye content intended for viewing by a left eye of the viewer and a right eye content intended for viewing by a right eye of the viewer;

[0013] - determining a field of view for each of the viewer’s eyes;

[0014] - determining a monocular screen area, which is a part of the total screen area that is outside the field of view for one eye of the viewer and inside the field of view for another eye of the viewer;

[0015] - displaying on the monocular screen area the left eye content without the right eye content or displaying on the monocular screen area the right eye content without the left eye content;

[0016] - displaying the stereoscopic content on a binocular screen area, which is a part of the total screen area that is within the field of view for both of the viewer’s eyes, by directing the left eye content to the left eye of the viewer and the right eye content to the right eye of the viewer.

[0017] The invention further relates to an autostereoscopic display device configured to display stereoscopic content on a total screen area of the autostereoscopic display device, wherein the autostereoscopic display device

[0018] - comprises a means for determining a field of view for each of the viewer’s eyes;

[0019] - comprises a means for determining a monocular screen area, which is a part of the total screen area that is outside the field of view for only one of the viewer’s eyes;

[0020] - is configured to display on the monocular screen area the left eye content without the right eye content or is configured to display on the monocular screen area the right eye content without the left eye content.

[0021] - is configured to display the stereoscopic content on a binocular screen area, which is a part of the total screen area that is within the field of view for both of the viewer’s eyes, by directing the left eye content to the left eye of the viewer and the right eye content to the right eye of the viewer.

[0022] BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 schematically displays a top view of a first setting wherein a first embodiment of the method of the invention is carried out. Figure 2 schematically displays a top view of a second setting wherein a second embodiment of the method of the invention is carried out.

[0024] Figure 3 schematically displays a top view of a third setting wherein a third embodiment of the method of the invention is carried out.

[0025] Figure 4 schematically displays a top view of a fourth setting wherein a fourth embodiment of the method of the invention is carried out.

[0026] Figure 5 schematically displays a top view of a fifth setting wherein a fifth embodiment of the method of the invention is carried out.

[0027] DETAILED DESCRIPTION OF THE INVENTION

[0028] The figures do not limit the present invention to the specific embodiments disclosed therein and described in the present description. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale, emphasis instead being placed upon clearly illustrating the principles of the invention. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various exemplary embodiments of the present invention. In particular, the relative dimensions of a viewer’s head features (in particular a nose), a field of view of an eye, and an autostereoscopic display screen cannot be derived from the figures. Also, the figures provide no quantitative indication of the mutual positioning of different autostereoscopic display screens, or of their positioning relative to a viewer.

[0029] Further, the terms ‘first’, ‘second’, and the like in the present patent application, if any, are generally used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order.

[0030] In the context of the invention, by the term ‘viewer’ is meant a person consuming the content that is presented to him by an autostereoscopic display system according to the present invention. The viewer may in particular view (e.g. watch) an autostereoscopic display device, where he sees a stereoscopic content, such as an image or a movie.

[0031] Further, a viewer is understood to be a real entity existing in the real world, such as a male or female person or animal. Throughout the text, references to the viewer will be made by male words like ‘he’, ‘him’ or ‘his’. This is however only for the purpose of clarity and conciseness, as it is understood that female words like ‘she’, and ‘her’ equally apply.

[0032] In the context of the present invention, by an autostereoscopic display device is meant a device that is configured to display stereoscopic content (such as an image or a movie) having a binocular depth perception by a viewer, without the use of special headgear, glasses, something that affects vision, or anything else that is present on the part of the viewer. This is achieved by directing a left eye content to a left eye of the viewer (and not to a right eye of the viewer) and a right eye content to a right eye of the viewer (and not a left eye of the viewer). When an autostereoscopic display device displays a stereoscopic image of a three-dimensional environment, then this environment is perceived in three dimensions. In this way, the autostereoscopic display device may be perceived as a virtual window to such scene. Autostereoscopic display devices are known in the art, e.g. from WO2013120785A2.

[0033] An autostereoscopic display device typically comprises a processor which is configured to produce left eye content and right eye content and to weave these contents to an array of pixels, thereby determining which pixels are to produce pixel output in correspondence with the respective left eye content and right eye content.

[0034] An autostereoscopic display device further comprises at least one screen for the actual displaying of the stereoscopic content, which is therefore termed ‘autostereoscopic display screen’. An autostereoscopic display device may comprise a single autostereoscopic display screen, but it may also comprise more than one of them. In this latter case, the stereoscopic content to be displayed is typically spread over the more than one autostereoscopic display screens. In this way, the autostereoscopic display device may also provide a plurality of virtual windows to a single three-dimensional scene. Alternatively, instead of displaying one single three-dimensional environment, the different autostereoscopic display screens may also display different three-dimensional environments, for example each autostereoscopic display screen may display a different three-dimensional environment.

[0035] The capability of an autostereoscopic display device to direct left eye content and right eye content to different spatial positions may be realized by different technical means. Two of these technical means that are often used in an autostereoscopic display device are a lenticular lens and a parallax barrier. In the context of the present invention, the term ‘view-forming arrangement' is a generic term for such technical means.

[0036] It is the autostereoscopic display screen in an autostereoscopic display device that actually comprises the view-forming arrangement. When there are a plurality of autostereoscopic display screens in an autostereoscopic display device, they usually all comprise either a lenticular lens or a parallax barrier. It is of course also possible that both technical means are present in one and the same autostereoscopic display device (one screen comprising a lenticular lens and another screen comprising a parallax barrier).

[0037] Irrespective of the number of autostereoscopic display screens belonging to a particular autostereoscopic display device, the autostereoscopic display device comprises a total screen area that is available for the display of stereoscopic content. In case of one autostereoscopic display screen, such total screen area is the screen area of that single screen. In case of a plurality of autostereoscopic display screens, such total screen area is typically the sum of the screen areas of that plurality of screens.

[0038] Thus, in an embodiment, the autostereoscopic display device comprises one or more autostereoscopic display screens, each of which has a screen area that is available for the display of stereoscopic content. Together, the screen areas of each autostereoscopic display screen usually make up the total screen area that is available for the display of stereoscopic content.

[0039] The number of autostereoscopic display screens in an autostereoscopic display device has no particular limit. It may for example be in the range of 1-16 or in the range of 2-8. There may for example be 2, 3, 4, 5, 6 or 7 screens.

[0040] In case there are two or more autostereoscopic display screens, then they may be positioned relative to one another to allow a viewer to become at least partially surrounded by the two or more autostereoscopic display screens.

[0041] For example, such screens may have particular relative orientations. Considering that each of the two or more autostereoscopic display screens defines a screen plane, then the screen planes defined by two of the two or more autostereoscopic display screens may have a particular screen plane angle with one another, for example a screen plane angle that is smaller than 180°, in particular smaller than 150°. For example, the angle is in the range of 60-120°. It may in particular be in the range of 80-100°.

[0042] An autostereoscopic display screen is not necessarily flat in that it defines a particular screen plane. It may also have a curved shape to allow a viewer to become at least partially surrounded by one or more autostereoscopic display screens.

[0043] In case there are two or more autostereoscopic display screens, then they may together form a video wall. This may be a wall wherein the different screens are essentially flat and wherein they together form a wall in essentially one single plane. It is on the other hand also possible that the wall is curved when the (flat) screens are positioned at an angle with respect to one another.

[0044] A method of the invention makes use of one or more autostereoscopic display screens. Such screen may be largely stationary in the real world during its use, such as a desktop screen, a wall-mounted screen or a screen in a simulation environment wherein a cockpit of a car or airplane is simulated. For example, the autostereoscopic display device is a television, a (desktop) computer with a monitor, a laptop, a cinema display system, a driving simulator or a flight simulator. It may however also be a portable device such as a mobile phone, a display in a car, a tablet or a game console, allowing a viewer to (freely) move in the real world together with the autostereoscopic display device.

[0045] In the context of the invention, the term ‘content’ is meant to include videos, pictures, still images, motion pictures, graphical user interfaces, graphical objects, animations, television broadcasts, live feeds, or any other content that is broadcast over the internet or other networks or that is stored on a storage medium for playback. Content may in particular be output of a graphics engine, e.g. for playing or creating games or for creating three-dimensional models.

[0046] Content may be monoscopic content or stereoscopic content. When displayed, monoscopic content is perceived in two dimensions, without a binocular depth perception. When displayed, stereoscopic content is perceived in three dimensions, having a binocular depth perception.

[0047] Stereoscopic content is composed of a left eye content intended for viewing by a left eye of the viewer and a right eye content intended for viewing by a right eye of the viewer. The left eye content and the right eye content together form a stereoscopic pair.

[0048] An important aspect of a method of the invention is that it identifies an area of the total screen area that is observable by only one eye of a viewer, i.e. it is out of a field of view of the other eye of the viewer. This is then an area where display of stereoscopic content essentially does not make sense because one of the eyes cannot see it. In the context of the invention, such area is named a ‘monocular screen area’.

[0049] The inventors realized that knowledge of a monocular screen area may form a useful starting point for reducing the workload demanded from a processor in an autostereoscopic display device; and possibly also for reducing crosstalk. In the method of the present invention, this is achieved by displaying only one of left eye content and right eye content on the monocular screen area (i.e. displaying left eye content without right eye content or displaying right eye content without left eye content). This means that, on the monocular screen area, monoscopic content is displayed rather than stereoscopic content.

[0050] The displaying of left eye content without right eye content or right eye content without left eye content on the monocular screen area may be performed in at least two ways. Two of these ways will now be explained for the situation wherein left eye content is to be displayed and no right eye content (as the right eye has no view on the monocular screen area).

[0051] In the first way, the pixels that were originally assigned to provide the right eye content are switched off or are given a color that resembles that of one or more neighboring pixels that are assigned to provide the left eye content. This may be an averaged color, obtained by averaging the colors of neighboring pixels.

[0052] In the second way, the pixels that were originally assigned to provide the right eye content are instructed to provide the left eye content, too.

[0053] Both ways apply mutatis mutandis to the situation wherein right eye content is to be displayed and no left eye content (as the left eye has no view on the monocular screen area).

[0054] Thus, the second way concerns displaying only right eye content on a monocular screen area when the monocular screen area cannot be observed by a viewer’s left eye; and it concerns displaying only left eye content on a monocular screen area when the monocular screen area cannot be observed by a viewer’s right eye.

[0055] As regards the first way, it is noted that switching off those pixels that provide the content that is out of the field of view of one eye is not preferred since the switching-off makes that the image for other eye looks a bit darker.

[0056] It is preferred that the displaying occurs according to the second way, because displaying one single content essentially kills any chance on crosstalk.

[0057] Any of both ways relieves the processor from the duty to constantly produce both left eye content and right eye content and to weave both contents to an array of pixels (as far as intended for monocular screen areas). Moreover, when pixel output that is intended for the eye that has no view on the monocular screen area is not emitted at all, then there is no risk that it leaks to the other eye (for which it is not intended), thereby reducing crosstalk. Important to note here is that especially at the oblique display angles that typically occur for a monocular screen area, the effective interpupillary distance is small, which on itself already makes the viewer more susceptible to crosstalk.

[0058] Besides the two ways described above, there is another means to display on the monocular screen area only one content (either left eye content or right eye content). This requires the use of a so-called 2D / 3D switchable autostereoscopic display screen that is capable of locally switching from a 2D mode to a 3D mode and vice versa. Such screens usually comprise a lenticular lens as the view-forming arrangement and a liquid crystal medium which can switch between two liquid crystalline orientations under the influence of an electrical field, one orientation corresponding to a 2D view mode and the other to a 3D view mode (in the 2D view mode, the particular liquid crystalline orientation has the effect that the refractive action of the lenticular lens is essentially cancelled and therefore essentially absent). By the feature ‘locally switchable’ is meant that the screen is capable of simultaneously providing 2D display areas and 3D display areas, wherein the size and position of these areas can be chosen freely and independently of one another, which includes that they can be controlled over time. When applied in a method of the present invention, the 2D display area is then generated in accordance with the monocular screen area and the 3D display area is then generated in accordance with the binocular screen area. As stated above, in a method of the invention there is an identification of an area of the total screen area that is observable by only one eye of a viewer (i.e. a monocular screen area). This identification is performed by first determining a field of view for each of the viewer’s eyes ( / .e. a field of view for a viewer’s left eye and a field of view for a viewer’s right eye) and then determining which part of the total screen area is outside the determined field of view for only one of the viewer’s eyes. This typically also requires data on the dimensions of each autostereoscopic display screen that is involved, as well as data on the position and orientation of each autostereoscopic display screen that is involved with respect to the determined field of view for each of the viewer’s eyes.

[0059] Besides the displaying of only left eye content or only right eye content on the monocular screen area, there of course also occurs a displaying of stereoscopic content on another screen area. This occurs on a screen area that is observable by both eyes of the viewer. In the context of the present invention, such area is termed a ‘binocular screen area’.

[0060] The presence of a monocular screen area and a binocular screen area on an autostereoscopic display screen is illustrated in Figure 1 . It schematically displays a first setting wherein a first embodiment of the method of the invention is carried out. In this first setting, a viewer (1 ) is present in front of an autostereoscopic display screen (2). The left eye of the viewer (1 ) has a left eye field of view (3a) and the right eye of the viewer has a right eye field of view (3b). These fields of view (3a, 3b) cover the autostereoscopic display screen (2). Areas of the autostereoscopic display screen (2) that are covered by only one field of view (3a or 3b) are marked as monocular screen area (4) and areas of the autostereoscopic display screen (2) that are covered by the two fields of view (3a, 3b) are marked as binocular screen area (5).

[0061] Figure 2 schematically displays a second setting wherein a second embodiment of the method of the invention is carried out. This second setting is similar to the first setting of Figure 1 , but with the difference that there are three autostereoscopic display screens (2a, 2b, 2c) rather than one. These three autostereoscopic display screens (2a, 2b, 2c) are surrounding the viewer (1 ) to a certain extent, wherein one central autostereoscopic display screen (2b) is in the center front of the viewer, flanked by a differently oriented outer autostereoscopic display screen (2a, 2c) on either side. The binocular screen area (5) stretches over the entire central autostereoscopic display screen (2b) and over a part of each outer autostereoscopic display screen (2a, 2c). The monocular screen area (4) only covers a part of the two outer autostereoscopic display screens (2a, 2c).

[0062] Figure 3 schematically displays a third setting wherein a third embodiment of the method of the invention is carried out. This third setting is similar to the second setting of Figure 2, but with the difference that there is a single autostereoscopic display screen (2) rather than three, which single screen (2) is curved around the viewer (1 ).

[0063] Figure 4 schematically displays a fourth setting wherein a fourth embodiment of the method of the invention is carried out. This fourth setting is similar to the second setting of Figure 2, but with the difference that the viewer (1 ) is positioned differently with respect to the autostereoscopic display screen (2). His head has turned to the left, causing the monocular screen area (4) and the binocular screen area (5) to move accordingly.

[0064] As can be seen in e.g. Figure 2 and Figure 5, the interface between a monocular screen area and a binocular screen area does not necessarily coincide with an interface between two autostereoscopic display screens. It may also run over one and the same autostereoscopic display screen. This means that, at a given moment, the screen area of a particular autostereoscopic display screen may comprise a first portion that represents a monocular screen area and a second portion that represents a binocular screen area.

[0065] As stated above, for the identification of the monocular screen area it is necessary to determine a field of view for each of the viewer’s eyes. Such a field of view may be defined in more than one way. For example, the field of view of an eye may be determined relative to viewer’s head. The field of view may then be represented by a cone that is fixed to the head, in particular to an eye socket such that the eyeball falls within the cone. A field of view for a particular eye is then defined irrespective of the orientation of the eye ball in the eye socket of that particular eye. The position of the field of view relative to the one or more autostereoscopic display screens of the autostereoscopic display device can then only be changed by head movement relative to the one or more autostereoscopic display screens (and not by e.g. eye movement in an eye socket). Such a field of view definition where account is taken of head position and orientation relative to the one or more autostereoscopic display screens requires a head tracking system wherein only the position of a head feature (such as an eye socket) is followed in time, but not an orientation of an eye in such socket.

[0066] In a more refined case, however, a field of view may indeed be determined with respect to an eyeball itself, requiring that the orientation of the eyeball in its eye socket is taken into account. The field of view of an eye may then be represented by a cone that is fixed to the eyeball, typically such that the iris falls within the cone. The position of the field of view relative to the one or more autostereoscopic display screens of the autostereoscopic display device can then be changed by head movement and / or by eyeball movement in the eye socket relative to the one or more autostereoscopic display screens. Translational movement of the field of view will then still mainly be due to movement of the head as a whole as eyeball movement in an eye socket is essentially limited to rotation (since the center of rotation of the eyeball is at a small distance from the pupil, the pupil itself undergoes some translation upon eyeball rotation). Such an eyeballbased field of view may for example be based on the size of the retina, the size of the iris, and the relative positioning of the iris and the retina. In this way, the field of view is of a conical shape, which has limits that are defined by the most oblique rays that can reach a defined border of the retina.

[0067] Such a field of view definition where account is taken of eyeball orientation in an eye socket (and thus of eyeball orientation relative to the one or more autostereoscopic display screens) typically requires an eye tracking system wherein not only the position of an eye (in particular the iris) is followed in time, but also its orientation (e.g. its gaze).

[0068] The fields field of view as described above have an absolute character in that they not depend on items that may be partially blocking the view of an eye, either temporarily or permanently. Any such blocking items may on the one hand be parts that are closely associated with the viewer and that essentially completely adopt all of the viewer’s head movements, for example his facial elements (nose, eyebrows, cheeks, and other areas surrounding an eye) or objects physically connected to the viewer’s head such as glasses and other (head) wearables. On the other hand, blocking items may be physical objects that do not belong to the viewer’s head or any wearables he may have on his head, for example a hand (of a viewer), a microphone, and a loudspeaker.

[0069] Thus, for the purpose of determining an eye’s field of view, one may take into account items that subtract from the field of view. And thus, for determining a monocular screen area one may take into account an occlusion of a part of the total screen area by a physical object such as a microphone; or by a body part of the viewer, such as a nose or an eye socket of the viewer.

[0070] The effect of occlusion by a nose on the monocular screen area and the binocular screen area is illustrated in Figure 5. It schematically displays a fifth setting wherein a fifth embodiment of the method of the invention is carried out. This fifth setting is similar to the second setting of Figure 2, but with the difference that the nose (6) of the viewer narrows the field of view (3a, 3b) of both eyes. This causes that the monocular screen area (4) is increased with respect to that of Figure 2 and that the binocular screen area (5) is reduced with respect to that of Figure 2.

[0071] When a method of the invention is performed, the determined monocular screen area is a reflection of the viewer position at a particular moment in time. The binocular screen area on which the stereoscopic content is displayed is then also a reflection of the viewer position at a particular moment in time. A certain amount of time later, the monocular screen area and the binocular screen area may have changed, typically due to movement of the viewer relative to the autostereoscopic display device, in particular relative to one or more autostereoscopic display screens thereof. This means that a monocular screen area and a binocular screen area may vary in size and position over time.

[0072] Therefore, a method of the invention is usually continuously repeated to account for viewer movement. A method of the invention is for example performed a plurality of times in a sequence, for example at least 10 times, at least 100 times, at least 1 ,000 times, at least 10,000 times, at least 100,000 times or at least 1 ,000,000 times.

[0073] If continuously repeated, a frequency can be defined for performing the method. On the one hand, for a realistic viewing experience, such frequency should not be too low. For example, a sudden viewer movement has to be quickly reflected in the displaying of the content. On the other hand, a too high frequency may ask too much computational power, which may impair the display of content and / or require too much energy. The frequency is for example at least 2 times per second, at least 5 times per second, at least 10 times per second, at least 20 times per second or at least 50 times per second. The frequency may also be the same frequency as a refresh rate of a screen of the autostereoscopic display device, in particular as a refresh rate of a screen of a binocular screen area.

[0074] In a method of the invention, there is the step of displaying left eye content without right eye content on the monocular screen area; or displaying right eye content without left eye content on the monocular screen area.

[0075] It is noted that this does not exclude the display of content other than left eye content or right eye content, respectively. It is for example also possible that the left eye content is substituted by a content that resembles the right eye content, preferably in a way that does not ask a high processing capacity from the processor. This may be realized by allowing pixels that would otherwise provide the left eye content to emit a color that resembles the emitted color of one or more neighboring pixels that provide the right eye content.

[0076] In a preferred embodiment, the type of displayed content (left or right content) is matched with the particular eye that has a view on the monocular screen area. Therefore, a method of the invention may be a method wherein

[0077] - a determined first monocular screen area is a part of the total screen area that is outside the field of view for only a viewer’s left eye; and

[0078] - right eye content is displayed on the first monocular screen area; and / or wherein

[0079] - a determined second monocular screen area is a part of the total screen area that is outside the field of view for only a viewer’s right eye; and

[0080] - left eye content is displayed on the second monocular screen area.

[0081] When, instead of displaying a stereoscopic image on the entire screen area that is available for display, part of the screen is devoted to the display of one of left eye content and right eye content (monocular screen area), then this relieves the processor from the duty to constantly produce both left eye content and right eye content for the entire screen area, and from the duty to weave both contents to one or more arrays of pixels which together represent the total screen area that is available for the display of stereoscopic content. This has the advantage that processor capacity is saved. This may then be used for more important tasks such as achieving that the displayed stereoscopic image quality in the binocular screen area is increased or at least may not become impaired due to a lack of processor capacity.

[0082] Another advantage is that energy consumption of the autostereoscopic display device as a whole may be decreased, which is more environmentally benign and may allow a reduction of a cooling capacity of the autostereoscopic display device or its direct environment, required to accommodate an excess heat that is generated by the autostereoscopic display device.

[0083] Yet another advantage is that the occurrence of crosstalk on at least the monocular screen area can be decreased when two of the same contents are displayed simultaneously (which happens when left content is replaced by right content or right content is replace by left content). When both eyes see the same content, it is inherent that crosstalk is absent.

[0084] In addition to displaying only one of left eye content and right eye content on a monocular screen area, one may also think of reducing the quality of displaying of a left or right eye content on the monocular screen area, preferably to an extent that the viewer does not notify any such reduction, or to an extent that is acceptable to the viewer. Such reduction may comprise the displaying of content on a monocular screen area at a lower refresh rate and / or at a lower resolution.

[0085] In many usual settings wherein a viewer is in front of a display screen, he is able to see essentially the entire screen, for example during watching television or working on a tablet. In many virtual and augmented reality settings, however, there is a desire to present a viewer with as much screen area as possible, because this contributes to the viewer’s immersion in a virtual environment. Screens in such setting are for example extremely large or there is a composition of a plurality of cooperating screens that are positioned around a viewer that so partially or completely surround him. One can even think of one or more curved screens surrounding a viewer.

[0086] In such settings, the present invention finds a particular useful application, because large screens and viewer-surrounding screens easily run the risk of getting out of the field of view of one eye (or even both eyes) of a viewer. The large portion of out-of-view screen area in such settings makes that much more processor capacity and energy can be saved when the method of the invention is applied. Therefore, it is preferred in a method of the invention that the autostereoscopic display device comprises a large autostereoscopic display screen (e.g. one having a diagonal of at least 100 cm such as a diagonal in the range of 120-360 cm) that is possibly even bended; or that it comprises two or more autostereoscopic display screens that surround a viewer. In the latter case, screen planes defined by two of the two or more autostereoscopic display screens have a screen plane angle with one another that is smaller than 180°, in particular smaller than 150°, preferably in the range of 80-130° or in the range of 90-110°.

[0087] Settings wherein a method of the invention can advantageously be applied concern for example games, driving simulators or flight simulators.

[0088] A method of the invention may also be applied in an office environment, where multiple autostereoscopic display devices are placed on a desk or platform. In such setting, a designer or architect may be allowed to make and / or watch his / her creation in a virtual form in three dimensions. In another example, a student, a worker or a researcher can study or modify the three-dimensional structure of an object, for example a molecular model or a virtual copy of a technical installation.

[0089] An autostereoscopic display device according to the invention is configured to perform a method according to the invention as described hereabove.

[0090] All of the above considerations with respect to elements of the method for displaying a stereoscopic content, in particular with respect to the one or more autostereoscopic display screens, the total screen area, the stereoscopic content, the left eye content, the right eye content, the field of view of an eye and the determining thereof, the monocular screen area and the determining thereof, equally apply to corresponding elements in an autostereoscopic display device according to the invention.

[0091] Such an autostereoscopic display device comprises a means configured to determine a field of view for each of the viewer’s eyes. Such means may comprise a device selected from the group of head trackers, eye trackers, and gaze trackers. In addition, a means for capturing a three-dimensional head shape may be present. Such means may specifically be configured to obtain a three- dimensional shape of one or more head features of a viewer, such as a nose, an eyebrow, a cheek, and other areas surrounding an eye. In a specific embodiment, an autostereoscopic display device of the invention comprises a means for determining whether a part of the total screen area is occluded by a head feature of which the three-dimensional shape had been determined.

[0092] An autostereoscopic display device of the invention typically comprises an autostereoscopic display screen, which is the part of the autostereoscopic display device that actually displays a stereoscopic image to a viewer. Such screen usually comprises an array of pixels for producing a display output and a view-forming arrangement, such as a parallax barrier or a lenticular lens, that is associated with the array to be able to direct a left eye image to the viewer’s left eye and a right eye image to the viewer’s right eye. An autostereoscopic display screen is usually driven by a processing unit.

[0093] An autostereoscopic display device of the invention may comprise a single autostereoscopic display screen or a plurality of autostereoscopic display screens, for example 2, 3, 4 or 5 screens, or 3-10 screens. The total screen area as defined for the autostereoscopic display device is then the sum of the screen areas of each of the one or more autostereoscopic display screens that are present. A single autostereoscopic display screen may represent the total screen area on its own. The total screen area may however also be spread over more than one autostereoscopic display screen, for example over 2, 3, 4 or 5 autostereoscopic display screens.

[0094] A plurality of autostereoscopic display screens may together form a video wall. This may be a wall wherein the different autostereoscopic display screens are essentially flat and wherein they together form a wall in essentially one single plane.

[0095] It is on the other hand also possible that the wall is curved, to allow a viewer to become at least partially surrounded by two or more autostereoscopic display screens. This may be achieved by using one or more curved autostereoscopic display screens or by positioning different (flat) autostereoscopic display screens under an angle. In an embodiment, the autostereoscopic display device comprises a processor and a memory, wherein the memory comprises computer-executable code that, when executed by the processor, causes the processor to perform the method for displaying a stereoscopic content on an autostereoscopic display device as described above.

[0096] The invention further relates to a computer readable medium comprising transitory or non-transitory data representing instructions to cause a processor system to perform the method for displaying a stereoscopic content on an autostereoscopic display device as described above. The invention further relates to software arranged to perform the method for displaying a stereoscopic content on an autostereoscopic display device as described above, when executed on a computer.

Claims

CLAIMS1 . Method for displaying a stereoscopic content on an autostereoscopic display device comprising a total screen area that is available for the display of stereoscopic content, the method comprising- providing the stereoscopic content, which comprises a left eye content intended for viewing by a left eye of the viewer and a right eye content intended for viewing by a right eye of the viewer;- determining a field of view for each of the viewer’s eyes;- determining a monocular screen area, which is a part of the total screen area that is outside the field of view of only one of the viewer’s eyes;- displaying on the monocular screen area one content of the left eye content and the right eye content;- displaying the stereoscopic content on a binocular screen area, which is a part of the total screen area that is within the field of view of both of the viewer’s eyes, by directing the left eye content to the left eye of the viewer and the right eye content to the right eye of the viewer.

2. Method according to claim 1 , wherein the autostereoscopic display device comprises a lenticular lens and / or a parallax barrier.

3. Method according to claim 1 or 2, wherein the autostereoscopic display device comprises one or more autostereoscopic display screens having a screen area that is available for the display of stereoscopic content.

4. Method according to claim 3, wherein two or more autostereoscopic display screens together form a video wall.

5. Method according to any one of claims 1-4, wherein the autostereoscopic display device comprises a 2D / 3D switchable autostereoscopic display screen that is locally switchable from a 3D view mode to a 2D view mode and vice versa; and wherein the monocular screen area of the 2D / 3D switchable autostereoscopic display screen is in the 2D view mode and the binocularscreen area of the 2D / 3D switchable autostereoscopic display screen is in the 3D view mode.

6. Method according to any one of claims 1-5, wherein the autostereoscopic display device comprises two or more autostereoscopic display screens, wherein- each of the two or more autostereoscopic display screens defines a screen plane; and- the screen planes defined by two of the two or more autostereoscopic display screens have a screen plane angle with one another that is smaller than 180°, in particular smaller than 150°.

7. Method according to any one of claims 1-6, wherein- a determined first monocular screen area is a part of the total screen area that is outside the field of view of only a viewer’s left eye; and- right eye content is displayed on the first monocular screen area; and / or wherein- a determined second monocular screen area is a part of the total screen area that is outside the field of view of only a viewer’s right eye; and- left eye content is displayed on the second monocular screen area.

8. Method according to any one of claims 1-7, wherein the displaying of content on a monocular screen area is performed at a lower refresh rate and / or at a lower resolution than the displaying of content on a binocular screen area.

9. Method according to any one of claims 1-8, wherein determining a monocular screen area takes into account occlusion of a part of the total screen area by a physical object such as a microphone; or by a body part of the viewer, such as a nose or an eye socket of the viewer.

10. Autostereoscopic display device configured to display stereoscopic content on a total screen area of the autostereoscopic display device, wherein the autostereoscopic display device- comprises a means for determining a field of view for each of the viewer’s eyes;- comprises a means for determining a monocular screen area, which is a part of the total screen area that is outside the field of view of only one of the viewer’s eyes;- is configured to display on the monocular screen area one content of the left eye content and the right eye content;- is configured to display the stereoscopic content on a binocular screen area, which is a part of the total screen area that is within the field of view of both of the viewer’s eyes, by directing the left eye content to the left eye of the viewer and the right eye content to the right eye of the viewer.1 1 .Autostereoscopic display device according to claim 10, comprising- means for obtaining a three-dimensional shape of one or more head features of a viewer;- means for determining which part of the total screen area is occluded by a head feature.

12. Autostereoscopic display device according to claim 10 or 1 1 , comprising a 2D / 3D switchable autostereoscopic display screen that is locally switchable from a 3D view mode to a 2D view mode and vice versa; and wherein the 2D / 3D switchable autostereoscopic display screen is configured to switch a first screen area of the 2D / 3D switchable autostereoscopic display screen to the 2D view mode when such first screen area is a part of the monocular screen area and to switch a second screen area of the 2D / 3D switchable autostereoscopic display screen to the 3D view mode when such screen area is a part of the binocular screen area.13.Autostereoscopic display device according to any one of claims 10-12, comprising a plurality of autostereoscopic display screens, for example 2, 3, 4 or 5 autostereoscopic display screens.

14. Autostereoscopic display device according to any one of claims 10-13, comprising one or more devices selected from the group of head trackers, eye trackers, and gaze trackers.

15. Autostereoscopic display device according to any one of claims 10-14, wherein the autostereoscopic display device comprises a processor and a memory, wherein the memory comprises computer-executable code that, when executed by the processor, causes the processor to perform the method according to any one of claims 1-9.

16. A computer readable medium comprising transitory or non-transitory data representing instructions to cause a processor system to perform the method according to any one of claims 1-9.

17. Software arranged to perform the method according to any one of claims 1-9 when executed on a computer.

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