Method for orienting content on an autostereoscopic display device

Abstract

The invention relates to a method for orienting stereoscopic content on an autostereoscopic display device, displayed to one or more viewers. In the method of the invention, at a certain moment during the displaying of the stereoscopic content, an instruction is received by the autostereoscopic display device to modify a displaying orientation of the content on the screen by a certain amount of rotation. When a standard content rotation would then performed for the autostereoscopic display device, in a way analogous to content rotation on a monoscopic display device, then a viewer will not experience a correct three-dimensional content. The invention solves this problem by taking account of the rotation already at the stage of weaving the stereoscopic content for the autostereoscopic display screen. An additional issue may arise when there is a rotation of the viewer relative to the autostereoscopic display device to such an extent that the viewer experiences an inverted depth. The invention provides a solution to this by swapping the images of a stereoscopic pair.

Description

[0001] METHOD FOR ORIENTING CONTENT ON AN AUTOSTEREOSCOPIC

[0002] DISPLAY DEVICE

[0003] FIELD OF THE INVENTION

[0004] The invention relates to a method for orienting content on an autostereoscopic display device and to a computer readable medium and software for performing such method. The invention further relates to an autostereoscopic display device.

[0005] BACKGROUND

[0006] Autostereoscopic displays play an increasingly important role in virtual reality and augmented reality applications. One of their most outstanding features is that they allow a viewer to perceive three-dimensional content without a dedicated eyewear device, also when the viewer moves relative to the display.

[0007] Key to this technology is the presence of a screen that comprises a lenticular lens or a parallax barrier placed in front of an array of pixels. Due to the lenticular lens or parallax barrier, light emitted by the pixels can be directed to particular spatial directions, which allows selective illumination of only one eye of a pair of eyes. By accurately controlling the pixels individually, possibly with the aid of real-time obtained eye position data, the screen can direct simultaneously a left eye content to a left eye of the viewer and a right eye content to a right eye of the viewer. The resulting stereoscopic content provides a depth perception to the viewer wherein elements in the content may appear in front of the display or behind the display.

[0008] For each given viewer position relative to the screen, there are alternating columns or bands of pixels that illuminate either a right eye or a left eye. The left eye content and the right eye content therefore need to be divided into columns that are to be assigned to the alternating pixel columns. The process to arrive at this kind of interlacing is called weaving. The device that performs the weaving is called a weaver.

[0009] During use of displays in general (monoscopic or autostereoscopic), there may be occasions where displayed content is rotated on the screen. For example when a viewer gives an instruction to the autostereoscopic display to do so, e.g. when he wants to view the content in a rotated fashion. In another instance, the autostereoscopic display may perform the rotation of displayed content automatically upon rotation of the screen itself around its optical axis, relative to the viewer. Such automatic content rotation is then allowed by a feature commonly known as ‘auto-rotate’. Especially mobile devices have this feature, since these devices are during use often subject to rotation relative to the user or viewer. Such rotation is then compensated for by counter-rotating the screen contents, so that the viewer does effectively not experience a content rotation.

[0010] The rotation of content on monoscopic devices, such as common mobile phones and television screens, is quite straightforward as all pixels can easily be given the same, new instruction, based on the original content that is to be displayed. This is however not the case for autostereoscopic displays that operate with a lenticular lens, a parallax barrier, or any other means for forming a plurality of views where light output for each pixel is modified so that it can only be seen from one or more specific directions or angles. With such autostereoscopic displays, the viewer will not experience a correct three-dimensional content when a standard content rotation is performed.

[0011] Another problem associated with rotation of an autostereoscopic display is that a viewer may perceive an inverted depth.

[0012] SUMMARY OF THE INVENTION

[0013] It is therefore an object of the present invention to provide a method to correctly display a content (e.g. a stereoscopic image or a stereoscopic video) on an autostereoscopic display device when the content is to be rotated on the screen of the device. It is in particular an object of the invention to provide a method for the (automatic) rotation of displayed content on the screen of an autostereoscopic display. It is also an object that with a method of the invention the correct displayed depth is maintained when an autostereoscopic display is rotated in front of the viewer around its optical axis.

[0014] It is also an object to provide an autostereoscopic display device that is capable of rotating displayed content. It is in particular an object that such device does not suffer from displaying a stereoscopic content with an inverted depth. It has now been found that one or more of these objects can be reached by performing a method for orienting content on an autostereoscopic display device to display a first content and a second content to one or more viewers, comprising the steps of

[0015] - providing an autostereoscopic display device comprising o an autostereoscopic display screen comprising an array of display pixel elements for producing a display output and a view-forming arrangement that is provided over the array, capable of directing the display output from different display pixel elements to different spatial positions within a field of view of the autostereoscopic display device to allow a display of a first content and a second content; o a weaver configured to receive content data representing the first content and the second content and to weave the first content and the second content for the autostereoscopic display screen;

[0016] - simultaneously displaying the first content and the second content to the one or more viewers of the autostereoscopic display device, the displayed first and second content having an initial displaying orientation on the autostereoscopic display screen, wherein the displaying of the first content and the second content comprises o receiving content data by the weaver representing the first content and the second content; then o weaving the first content and the second content for the autostereoscopic display screen by determining for each display pixel element in the array whether it provides display output for the first content or for the second content, the array having an initial array orientation as seen from the weaver’s point of view; then o controlling the display pixel elements accordingly, to display the first content and the second content with the initial displaying orientation on the autostereoscopic display screen;

[0017] - wherein, at a certain moment during the displaying of the first and the second content, an instruction is received by the autostereoscopic display device to modify a displaying orientation of the first content and the second content on the autostereoscopic display screen by a known amount of rotation with respect to the initial displaying orientation so that, after execution of the instruction, the displayed first and second content have a modified displaying orientation on the autostereoscopic display screen; wherein, after receipt of the instruction,

[0018] - the weaving for the autostereoscopic display screen is performed with a modified array orientation as seen from the weaver’s point of view, which concerns an array orientation that is modified with respect to the initial array orientation by an amount of rotation that is equal to the known amount of rotation according to the received instruction;

[0019] - the received instruction to modify the displaying orientation of the first and the second content on the autostereoscopic display screen by a known amount of rotation is executed.

[0020] The invention further relates to an autostereoscopic display device configured to display a first content and a second content to one or more viewers, the autostereoscopic display device comprising

[0021] - an autostereoscopic display screen comprising an array of display pixel elements for producing a display output and a view-forming arrangement provided over the array, capable of directing the display output from different display pixel elements to different spatial positions within a field of view of the autostereoscopic display device to allow a display of a first content and a second content;

[0022] - a weaver configured to receive content data representing the first content and the second content and to weave the first content and the second content for the autostereoscopic display screen;

[0023] - a processor and a memory, wherein the memory comprises computerexecutable code that, when executed by the processor, causes the processor to perform the method for orienting content on an autostereoscopic display device as described above.

[0024] 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 orienting content on an autostereoscopic display device as described above. The invention further relates to software arranged to perform the method for orienting content on an autostereoscopic display device as described above, when executed on a computer.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 displays a flowchart representing a conventional process for displaying first and second content on an autostereoscopic display device.

[0027] Figure 2 displays a flowchart representing a process according to the invention for displaying first and second content on an autostereoscopic display device.

[0028] Figure 3 displays two different displaying orientations of a particular stereoscopic content on a mobile autostereoscopic display device.

[0029] Figure 4 is a complete image of the stereoscopic content of which parts are displayed in the two different displaying orientations of Figure 3.

[0030] DETAILED DESCRIPTION OF THE INVENTION

[0031] 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.

[0032] Further, the terms “first”, “second”, and the like in the present description and claims, if any, are generally used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order.

[0033] In the context of the invention, by the term ‘autostereoscopic display device’ is meant a device capable of displaying at least a first content and a second content to different spatial positions. Together, both may form a stereoscopic pair to allow a viewer to view a stereoscopic content. Alternatively, an autostereoscopic display device may also display a first content and a second content to two different persons, allowing each of them to view a monoscopic content. In case the autostereoscopic display device is capable of also displaying a third content and a fourth content, then two different persons may each view a stereoscopic content.

[0034] In the context of the invention, by the term ‘viewer’ is meant a person who can consume, in particular view, content presented by an autostereoscopic display device. Throughout the text, references to the viewer will be made by male words like ‘he’, ‘him’ or ‘his’. This is only for the purpose of clarity and conciseness, and it is understood that female words like ‘she’, and ‘her’ equally apply. The same applies to references in the text to the term ‘user’.

[0035] 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.

[0036] In the context of the invention, by the term ‘optical axis’ of an autostereoscopic display device or a screen thereof is meant a straight line that passes normal to the screen and through the geometrical center of the screen.

[0037] The method according to the present invention is performed for an autostereoscopic display device of which a weaver uses first content data and second content data to allow the autostereoscopic display screen to display these data as a first content and a second content. The autostereoscopic display screen comprises an array of display pixel elements for producing display output and a view-forming arrangement that is associated with the array, in particular provided over the array. The view-forming arrangement typically comprises a lenticular lens or a parallax barrier. Lenticular elements of a lenticular lens and elongated slits of a parallax barrier are capable of directing the display output from different display pixel elements in the array to different spatial positions within a field of view of the autostereoscopic display device. In this way, it is possible to display the first content (e.g. a first image) at a first viewing position and the second content (e.g. a second image) at a second viewing position.

[0038] There may also be other types of view-forming arrangements that are capable of directing the display output from different display pixel elements in the array to different spatial positions within a field of view of the autostereoscopic display device. An alternative display technology for a view-forming arrangement is for example a technology known as ‘directional backlight’.

[0039] When content is displayed on an autostereoscopic display screen with a view-forming arrangement, then there are alternating bands or columns of display pixel elements that illuminate either the first viewing position or the second viewing position. Each content to be viewed (e.g. each image) therefore needs to be divided into bands or columns that are to be assigned to the alternating pixel columns. The process to arrive at this kind of interlacing of content entails a number of calculations and is called ‘weaving’. This process is performed by a device that is called ‘weaver’. The result of the weaving of a content is called a ‘weaved content’. After the weaving, the display pixel elements are instructed to produce display output that is in accordance with the weaved contents.

[0040] The displayed first and second content in a method of the invention have a displaying orientation on the autostereoscopic display screen. This means that such content has an orientation with respect to the autostereoscopic display screen (for completeness’ sake it is noted that a ‘displaying orientation’ does e.g. not refer to an orientation of the autostereoscopic display screen itself). From the start of the method, the displayed contents are considered to have an initial displaying orientation, until, at a certain moment during the displaying of the first and the second content, an instruction is received by the autostereoscopic display device to modify the initial displaying orientation of the first and second content on the autostereoscopic display screen. This modification entails a certain amount of rotation. This means that, after execution of the instruction, the displayed first and second content have a modified displaying orientation on the autostereoscopic display screen, which is different from the initial orientation. This may or may not occur concurrently with a change in orientation of the autostereoscopic display screen itself, relative to the real world (which will be further elaborated below).

[0041] To arrive at a proper display of the first and second contents with such modified orientation is however not straightforward. Simply using the weaver output to control display pixel elements on a rotated array of display pixel elements appeared to yield a hugely impaired display of the first and second contents.

[0042] A flowchart representing such a conventional process is shown in Figure 1 . At a certain moment during the displaying of the first and second content, an instruction is received to modify the display orientation. From that moment on, this modification is constantly performed on the weaved content data; i.e. before the controlling of the pixels and after the weaving of the first and second content data. This does however not result in a properly displayed stereoscopic content.

[0043] The inventors contemplated that calibration parameters of the assembly of the view-forming arrangement with the array of display pixel elements cannot be directly used for other displaying orientations. The problem could surprisingly be solved by taking into account, during the weaving of the first and second contents, the orientation of the array of display pixel elements relative to the contents to be weaved. The autostereoscopic display device was programmed such that the received instruction to modify the initial displaying orientation would trigger a virtual rotation of the array of display pixel elements before the performing of the weaving of the first and second content. To this end, an initial array orientation and a modified array orientation were defined for the purpose of the weaving. From the start of the method, the array is then considered to have the initial array orientation, for the purpose of the weaving (i.e. as seen from the weaver’s point of view). This means that, for the weaving of the first content and the second content before receipt of the instruction to modify a displaying orientation, the weaver determines for each display pixel element in the array with the particular initial array orientation, whether it provides display output for the first content or for the second content, Once the rotation instruction is received, the virtual rotation takes place so that the array has a modified array orientation as seen from the weaver’s point of view. This means that the weaving of the first content and the second content is then performed for the rotated array (i.e. when the array has the particular modified array orientation). When the display pixel elements are thereafter controlled in correspondence with the rotation instruction, then the first and second content are correctly displayed with the modified rotation.

[0044] The wording “as seen from the weaver’s point of view” has to be understood in a more abstract manner rather than as a true physical setting wherein the weaver has a view on the array. The following will explain this. When a weaver starts with determining for each display pixel element whether it provides display output for the first content or for the second content, the weaver normally starts with the pixel in the upper left corner of the array. Let’s designate this pixel as ‘starting pixel’. After a virtual rotation of the array from an initial array orientation to a modified array orientation, the pixel that was designated as ‘starting pixel’ before the virtual rotation took place, is not anymore in the upper left corner, ‘as seen from the weaver’s point of view’. The programming of the weaver now dictates that another pixel is designated as ‘starting pixel’, i.e. the pixel that is now in the upper left corner of the array as seen from the weaver’s point of view.

[0045] A flowchart representing such process according to the invention is shown in Figure 2. At a certain moment during the displaying of the first and second content, an instruction is received to modify the display orientation. From that moment on, the weaving is then constantly performed for a screen with a modified orientation, and only thereafter the actual modification of the display orientation is performed. This does then result in a correct display of stereoscopic content that is rotated with respect to the autostereoscopic display screen.

[0046] The known amount of rotation may in principle be any amount of rotation between 0° and 360°. Usually, however, the amount of rotation is selected from the group of 90°, 180° and 270°.

[0047] Usually, the autostereoscopic display device in a method of the invention comprises an eye tracking system for determining the position of the eyes of the one or more viewers relative to the autostereoscopic display device. Such eye tracking system typically comprises means for tracking the position of the eyes of the one or more viewers relative to the autostereoscopic display device and is operably connected to the autostereoscopic display device. In this way, a left eye of a viewer can accurately be presented with a left eye content and a right eye of a viewer can accurately be presented with a right eye content, allowing the viewer to see a stereoscopic content. Alternatively, a first viewer can accurately be presented with a first monoscopic (or stereoscopic) content and a second viewer can accurately be presented with a second monoscopic (or stereoscopic) content, allowing each of both viewers to see their own monoscopic (or stereoscopic) content.

[0048] Alternatively or in addition to such eye tracking system, the autostereoscopic display device may comprise a head tracking system for determining a position of a head or a head feature of each of one or more viewers, the head or head feature representing an average position of the eyes of each of the one or more viewers, for example a single position, wherein the position of the eyes of a viewer is averaged to yield the single position. In this way, a first viewer can accurately be presented with a first monoscopic (or stereoscopic) content and a second viewer can accurately be presented with a second monoscopic (or stereoscopic) content, allowing each of both viewers to see a different monoscopic (or stereoscopic) content.

[0049] The instruction to the autostereoscopic display device is often an instruction given by a user of the autostereoscopic display device via a user interface, for example via a keyboard shortcut, a mouse, a graphical user inface, a device capable of gesture recognition or a device capable of speech recognition. Usually, the user is a viewer of the autostereoscopic display device.

[0050] The instruction may however also be generated by a dedicated device or component of the autostereoscopic display device rather than by a user or viewer. This is for example the case when the autostereoscopic display device is equipped with a so-called “auto-rotate” feature, which is known in the art as a feature that allows a display device's screen to automatically rotate depending on how a user or viewer holds it. For example, if a viewer turns his phone sideways by rotating it around its optical axis, then the screen will automatically switch to landscape mode by performing a counter-rotation of the displayed content.

[0051] Such display device is then typically capable of measuring or determining its orientation relative to the ground, and is configured to instruct a rotation of the content as displayed on the screen, e.g. when it detects a certain discrepancy between a measured or determined orientation and a displayed orientation. Thus, in a method of the invention, the instruction to the autostereoscopic display device may be an instruction given by a component of the autostereoscopic display device or by a further device associated with the autostereoscopic display device, that is configured to use a measured or inferred orientation of the autostereoscopic display device relative to the ground for deciding to give the instruction.

[0052] For example, such device is configured to compare a measured or inferred orientation of the autostereoscopic display device relative to the ground with a pre-set value for the orientation of the autostereoscopic display device relative to the ground and to decide on giving the instruction based on the comparison made.

[0053] A measured or inferred orientation of such device is usually obtained by a measuring instrument selected from the group of gyroscopes, magnetometers, accelerometers, gravimeters and inclinometers.

[0054] The decision to give the instruction may however also be made based on the orientation of the autostereoscopic display device relative to a viewer of the autostereoscopic display device. This in particular concerns the orientation of the autostereoscopic display device relative to the eyes of a viewer (as derived from a roll inclination of the head of the viewer). Such autostereoscopic display device usually comprises a face-tracker or eye tracker, to constantly monitor the viewer’s roll inclination relative to the autostereoscopic display device.

[0055] In a method of the invention, the first content and the second content may be content that is viewed by different persons, e.g. the first content by a first person and the second content by a second person. Two persons may so see different content when watching one and the same autostereoscopic display device.

[0056] Alternatively, the first content and the second content may be viewed by a single viewer, by directing the first content to his first eye and the second content to his second eye. When the first content and the second content together form a stereoscopic pair of a stereoscopic content, then he can view a stereoscopic content.

[0057] It is also possible to provide two viewers with different stereoscopic contents by directing to each viewer a stereoscopic pair of a stereoscopic content. This would require the display of a third content and a fourth content.

[0058] The lenticular lens elements in a lenticular lens and the elongated slits in a parallax barrier are elongated elements that direct display pixel output in different directions perpendicular to the direction of their elongation (also known as the direction of slant). Stereoscopic viewing can therefore only be accomplished when there is a parallax shift (disparity), or a component thereof, in the direction of an imaginary interpupillary line of the viewer. When, during rotation of an autostereoscopic display screen relative to a viewer, this situation is crossed, then left eye content will be directed at the right eye and vice versa. This will be experienced by the viewer as an inverted depth of the displayed content (which is not necessarily impaired in other aspects). Thus, simply rotating an autostereoscopic display screen around its optical axis in front of a viewer may cause an inverted depth of a viewed stereoscopic content. This may be cured by weaving left eye content to display pixel elements that direct their output to the right eye and vice versa. Thus, in addition to modifying a displaying orientation of content according to a method of the invention, an inverted depth due to screen rotation may be corrected for in a particular embodiment of the invention where a stereoscopic content is viewed.

[0059] Accordingly, in a method of the invention, it may be checked whether there is a rotation of the autostereoscopic display screen relative to the viewer to an extent that has the effect that the left eye content is directed at a right eye of the viewer and that the right eye content is directed at a left eye of the viewer to thereby cause that an inversion of depth is perceived by the viewer if not corrected for. Such check may be performed a plurality of times, for example at regular intervals, such as once per second or five times per second.

[0060] Further, in the event that a rotation is observed that would cause an inversion of depth for the viewer, the left eye content and the right eye content may be swapped so that the left eye content is again directed at a left eye of the viewer and the right eye content is again directed at a right eye of the viewer.

[0061] In certain cases, the autostereoscopic display device in a method of the invention is configured to modify the content to be displayed when it receives an instruction to modify a displaying orientation of the content on the screen. If such modification is performed, then this usually concerns a response to a change of displaying orientation from a landscape mode to a portrait mode or vice versa. The change in aspect ratio that is associated with such change may result in an undesired change in the proportion of the content, for example a stretch in a particular direction. This can be relieved by cropping the content or by shrinking the content (without changing its proportion) together with addition of new areas to the content. Another way to relieve this, is by adapting the lay-out of the content (e.g. rearranging text and / or figures in the content). Thus, in a method of the invention, after receipt of the instruction and before the weaving for the autostereoscopic display screen, the weaver may receive modified content data, representing modified first content and modified second content.

[0062] Herein, the modified first content and the modified second content may be modified in that their aspect ratios are modified so as to correspond to an aspect ratio of the array of display pixel elements. The aspect ratios may for example be modified by one or more actions selected from the group of

[0063] - removing one or more areas from the first content and the second content;

[0064] - resizing one or more areas of the first content and the second content;

[0065] - adding one or more areas to the first content and the second content.

[0066] Any such modification of content data is usually however not necessary when the content to be displayed is a part of a virtual three-dimensional environment or of a ‘digital twin’ of a real environment, as such environment comprises more content data than the content data used for the displaying with the a particular displaying orientation. The required additional data for generating content with the modified displaying orientation can easily be obtained from the data representing the entire virtual three-dimensional environment or the entire digital twin.

[0067] This is visualized in Figure 3, which displays two different displaying orientations of a particular stereoscopic content on a mobile autostereoscopic display device - a virtual beach scene. In the top picture of Figure 3, the beach scene is displayed in a landscape orientation and in the bottom picture of Figure 3 it is displayed in a portrait orientation. In the landscape orientation, different parts of the beach scene are visible than in the portrait orientation; while other parts (e.g. central parts) are present in both orientations. For completeness’ sake, the entire beach scene is displayed in Figure 4.

[0068] One of the most outstanding features of autostereoscopic display devices is that they allow a viewer to perceive a displayed three-dimensional scene without a dedicated eyewear device such as a head set, a head-mounted display, glasses, etc. An attractive capability that may be implemented in such devices is a capability to adapt displayed content to the position and orientation of the device. When this is performed to an extent that the displayed content represents a scene that is fixed to the real world rather than to the screen, then the screen of the device essentially acts as a virtual window. The absence of a dedicated eyewear device then allows 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.

[0069] A method of the invention as visualized in Figure 3 is particularly advantageous for an autostereoscopic display device with a virtual window capability, because a displayed virtual scene is then typically larger than the screen ( / .e. the virtual window) itself.

[0070] The invention further relates to an autostereoscopic display device configured to display a first content and a second content to one or more viewers, the autostereoscopic display device comprising

[0071] - an autostereoscopic display screen comprising an array of display pixel elements for producing a display output and a view-forming arrangement provided over the array, capable of directing the display output from different display pixel elements to different spatial positions within a field of view of the autostereoscopic display device to allow a display of a first content and a second content;

[0072] - a weaver configured to receive content data representing the first content and the second content and to weave the first content and the second content for the autostereoscopic display screen;

[0073] - a processor and a memory, wherein the memory comprises computerexecutable code that, when executed by the processor, causes the processor to perform the method for orienting content on an autostereoscopic display device as described above.

[0074] 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 determining a position of a sub-pixel in a pixel arrangement as described above.

[0075] 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 orienting content on an autostereoscopic display device as described above. The invention further relates to software arranged to perform the method for orienting content on an autostereoscopic display device as described above, when executed on a computer.

Claims

CLAIMS1 . Method for orienting content on an autostereoscopic display device to display a first content and a second content to one or more viewers, comprising the steps of- providing an autostereoscopic display device comprising o an autostereoscopic display screen comprising an array of display pixel elements for producing a display output and a view-forming arrangement that is associated with the array, capable of directing the display output from different display pixel elements to different spatial positions within a field of view of the autostereoscopic display device to allow a display of a first content and a second content; o a weaver configured to receive content data representing the first content and the second content and to weave the first content and the second content for the autostereoscopic display screen;- simultaneously displaying the first content and the second content to the one or more viewers of the autostereoscopic display device, the displayed first and second content having an initial displaying orientation on the autostereoscopic display screen, wherein the displaying of the first content and the second content comprises o receiving content data by the weaver representing the first content and the second content; then o weaving the first content and the second content for the autostereoscopic display screen by determining for each display pixel element in the array whether it provides display output for the first content or for the second content, the array having an initial array orientation as seen from the weaver’s point of view; then o controlling the display pixel elements accordingly, to display the first content and the second content with the initial displaying orientation on the autostereoscopic display screen;- wherein, at a certain moment during the displaying of the first and the second content, an instruction is received by the autostereoscopic display device to modify a displaying orientation of the first content and the secondcontent on the autostereoscopic display screen by a known amount of rotation with respect to the initial displaying orientation so that, after execution of the instruction, the displayed first and second content have a modified displaying orientation on the autostereoscopic display screen; wherein, after receipt of the instruction,- the weaving for the autostereoscopic display screen is performed with a modified array orientation as seen from the weaver’s point of view, which concerns an array orientation that is modified with respect to the initial array orientation by an amount of rotation that is equal to the known amount of rotation according to the received instruction;- the received instruction to modify the displaying orientation of the first and the second content on the autostereoscopic display screen by a known amount of rotation is executed.

2. Method according to claim 1 , wherein the known amount of rotation is between 0° and 360°, in particular it is selected from the group of 90°, 180° and 270°.

3. Method according to claim 1 or 2, wherein the autostereoscopic display device further comprises- an eye tracking system for determining a position of the eyes of the one or more viewers relative to the autostereoscopic display device; and / or- a head tracking system for determining a position of a head or a head feature of the one or more viewers, representing a position of the eyes of each of the one or more viewers relative to the autostereoscopic display device.

4. Method according to any one of claims 1-3, wherein the instruction to the autostereoscopic display device is an instruction given by a user of the autostereoscopic display device via a user interface, for example via a keyboard shortcut, a mouse, a graphical user inface, a device capable of gesture recognition or a device capable of speech recognition.

5. Method according to any one of claims 1-3, wherein the instruction to the autostereoscopic display device is an instruction given by a component of the autostereoscopic display device or by a further device, configured to use a measured or inferred orientation of the autostereoscopic display device relative to the ground or relative to a viewer of the autostereoscopic display device for deciding to give the instruction.

6. Method according to claim 5, wherein the component or the further device is configured to compare the measured or inferred orientation of the autostereoscopic display device relative to the ground or relative to a viewer of the autostereoscopic display device with a pre-set value for the orientation of the autostereoscopic display device relative to the ground or a viewer of the autostereoscopic display device, respectively, and to decide on giving the instruction based on the comparison made.

7. Method according to claim 5 or 6, wherein the measured or inferred orientation is obtained by a measuring instrument selected from the group of gyroscopes, magnetometers, accelerometers, gravimeters and inclinometers.

8. Method according to any one of claims 1-7, wherein the view-forming arrangement comprises a lenticular lens, a parallax barrier or an arrangement that is based on the principle of directional backlight.

9. Method according to any one of claims 1-8, wherein the first and the second content include, independently of one another, 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.

10. Method according to claim 9, wherein the first and the second content are a left eye content intended for viewing by a left eye of a viewer and a right eye content intended for viewing by a right eye of a viewer, which together form astereoscopic pair of a stereoscopic content that is to be viewed by a single viewer.11 . Method according to claim 10, wherein it is checked whether there is a rotation of the autostereoscopic display screen relative to the viewer to an extent that has the effect that left eye content is directed at a right eye of the viewer and that right eye content is directed at a left eye of the viewer to thereby cause that an inversion of depth is perceived by the viewer if not corrected for.

12. Method according to claim 1 1 , wherein, in the event that a rotation is observed that would cause an inversion of depth for the viewer, the left eye content and the right eye content are swapped so that left eye content is again directed at a left eye of the viewer and that right eye content is again directed at a right eye of the viewer.

13. Method according to any one of claims 1-12, wherein, after receipt of the instruction, the weaver receives modified content data, representing modified first content and modified second content.

14. Method according to claim 13, wherein the modified first content and the modified second content are modified in that their aspect ratios are modified so as to correspond to an aspect ratio of the array of display pixel elements.

15. Method according to claim 14, wherein the aspect ratios are modified by one or more actions selected from the group of- removing one or more areas from the first content and the second content;- resizing one or more areas of the first content and the second content;- adding one or more areas to the first content and the second content.

16. Autostereoscopic display device configured to display a first content and a second content to one or more viewers, the autostereoscopic display device comprising- an autostereoscopic display screen comprising an array of display pixel elements for producing a display output and a view-forming arrangement that is associated with the array, capable of directing the display output from different display pixel elements to different spatial positions within a field of view of the autostereoscopic display device to allow a display of a first content and a second content;- a weaver configured to receive content data representing the first content and the second content and to weave the first content and the second content for the autostereoscopic display screen;- a processor and a memory, wherein the memory comprises computerexecutable code that, when executed by the processor, causes the processor to perform the method according to any one of claims 1-15.

17. 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 1-15.

18. Software arranged to perform the method according to any one of claims 1-15 when executed on a computer.

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