CN105988220B - Method and control device for operating an autostereoscopic field display for a vehicle - Google Patents

Abstract

The invention relates to a method ( 1500 ) for operating an autostereoscopic field of view display ( 102 ) for a vehicle ( 100 ), wherein the method ( 1500 ) has an adjustment step ( 1502 ). Here, the convergence angle ( 702) to adjust the misalignment (700) between the right image (402) and the left image (404) of the field of view display (102). The images (402, 404) are adjusted without misalignment when the viewing axes (502) intersect in the projection plane (504) of the images (402, 404).

Description

Method and control for operating an autostereoscopic field of view display for a vehicle equipment

technical field

The invention relates to a method for operating an autostereoscopic visual field display for a vehicle, a corresponding control device and a corresponding computer program.

Background technique

WO 1998/035260 A1 describes a holographic screen which can be depicted by means of a laser projector and which can be integrated into a windshield.

The publication "Exploring Design Parameters for a 3D Head-Up Display; Broy; Höckh; Frederksen et al; Pervasive Displays 2014" describes a stereoscopic head-up display.

SUMMARY OF THE INVENTION

Based on this background, a method for operating an autostereoscopic field-of-view display for vehicles is proposed with the solution proposed here, a control device using the method and finally a corresponding Computer program. An advantageous refinement consists in that the method comprises the steps of determining the position of the right and left images in the projection plane using the visual axis and the position of the eyes of the observer, wherein in addition In an adjustment step, the determined position is adjusted; the method has the steps of reading in eye information by an eye detection device of the vehicle, which is designed to detect the right and left eyes of the observer, wherein the eye position is imaged with the right eye position value and the left eye position value of the eye information, and the right visual axis and the left visual axis are imaged with the right and left radial values of the eye information, wherein the adjustment In the step of , the convergence angle is obtained from the viewing direction value and the eye position value; wherein in the adjustment step, the dislocation is adjusted in the comfort zone related to the observer; the method has the function of matching the comfort zone. wherein the comfort zones are matched in response to user input; wherein in the matching step, the comfort zones are matched in relation to the number of depth surfaces to be displayed, wherein when all when the number of said depth planes increases, the comfort zone is reduced; the comfort zone is changed in relation to the user, wherein when the observer is tired, the comfort zone is reduced; wherein in the step of matching, in the process of using eye information Observer fatigue was identified under conditions; where eyelid closure frequency and/or eyelid closure duration were assessed.

In field-of-view displays with the same image for the right and left eye of the observer, parallax errors occur when the image is viewed together with one or more target objects arranged at another distance. This double image is filtered by the observer's brain in such a way that one of the eyes is preferably used for viewing. Considerable brain effort is required to filter here.

In the scheme proposed here, the right image is provided for the observer's right eye and the left image is provided for the left eye in order to rule out parallax errors. A virtual image is formed here, which can be arranged approximately freely in space. The spatial position of the image can here be adjusted as a function of the viewing distance of the observer. In particular, the angle of convergence between the visual axes of the eyes can be assessed.

A method for operating an autostereoscopic field of view display for a vehicle is proposed, wherein the method comprises the steps of:

adjusting the misalignment between the right and left images of the field of view display using the angle of convergence between the right visual axis of the right eye and the left visual axis of the left eye of the observer using the field of view display, Wherein the image is adjusted without misalignment when the viewing axes intersect in the projection plane of the image.

The autostereoscopic field of view display can be understood as a head-up display or a windshield display or a front window display. In this case, the field of view display is designed to display two images on the projection surface, wherein only the right image is visible to the right eye of the observer. The observer's left eye can only see the left image. The right image is only visible in the viewing area on the right. The left image is only visible in the viewing area on the left. For example, a holographic element of a field of view display may have directional reflective properties. The offset can be a stroke in order to offset the image points of the right-hand image and the left-hand image which correspond to one another in the projection plane.

In this case, mutually corresponding image points can be mutually corresponding pixels or image elements of the left and right images, which are projected on the projection surface with the offset. Hence, the misalignment is referred to as a stroke in order to show that the right image moves relative to the left image. A misaligned display of the right image and the left image can be understood as a display in which the right image and the left image overlap (in particular completely), and thus the corresponding image point of the right image is in the left image imaged on the corresponding image point. The observer may be the driver of the vehicle.

The method may comprise the step of determining the position of the image in the projection surface. The determination may be accomplished using the observer's visual axis and eye position. In the adjustment step, the determined position can also be adjusted. The images can be moved together in the projection plane without changing the misalignment. The head movements of the observer can thus be compensated for.

The method may comprise the step of reading in eye information by an eye detection device of the vehicle. The eye detection device is designed to detect the eyes of an observer. The eye position is imaged with the right eye position value and the left eye position value. The boresight is imaged with right and left boresight values. The convergence angle is obtained from the viewing direction value and the eye position value. The eye information can thus be processed in real time. The misalignment can thus be adjusted quickly.

The misalignment can be adjusted within the comfort zone relative to the observer. Within the comfort zone, the observer can combine the two images into a stereoscopic viewing experience without too much effort. As a result, a lower burden on the observer can be achieved.

The method may include the step of matching comfort zones. In this case, the comfort zone can be adapted in a way that it responds to the user's input. The comfort zone can be adjusted in relation to the load state of the observer. The comfort zone can be reduced when the observer is striving. The observer can enter and/or change the desired value for the comfort zone through the user interface.

The comfort zone can be adapted as a function of the number of depth surfaces to be displayed. When the number of the depth planes increases, the comfort zone can be reduced. The target object can be shown at different distances. The target object is assigned a depth surface here. Multiple displayed depth planes may be more laborious to view than a few displayed depth planes. So it is possible to shrink the comfort zone inside which the target object is displayed.

The comfort zone can be changed in relation to the user. When the observer is tired, the comfort zone can be reduced. As a result, the load on the observer can be reduced. Thus the observer can recover.

Observer fatigue can be identified using eye information. In particular, the eyelid closure frequency can be assessed, and alternatively or additionally the eyelid closure duration can be assessed. The eye information can reliably detect whether the user is tired. When the user recovers, the comfort zone can be re-enlarged.

The solution proposed here furthermore enables a control device which is designed to carry out, actuate or carry out the steps of the variants of the method proposed here in a corresponding device. The object of the invention can also be achieved quickly and efficiently by means of an embodiment variant of the invention in the form of a control device.

A control device can be understood here as an electrical device which processes sensor signals and transmits control signals and/or data signals in connection therewith. The control device may have an interface, which may be formed by hardware and/or software. In the case of hardware configuration, the interface can, for example, be part of a so-called system-ASIC, which contains the most different functions of the control device. However, the interface may also be a separate integrated circuit or at least partly consist of discrete components. When formed in software, the interfaces can be software modules, which are present alongside other software modules, for example on a microcontroller.

A computer program product or a computer program having a program code that can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, hard disk memory or optical memory and used for execution, implementation and/or The steps of the method according to one of the preceding embodiments are handled, in particular when the program product or program is executed on a computer or device.

Description of drawings

The solution proposed here is explained in more detail below by way of example with the aid of the drawings. in:

Figure 1 shows an illustration of a vehicle with a field of view display;

Figure 2 shows an illustration of a traffic scene from a driver's perspective focused on a vehicle traveling in front;

Figure 3 shows an illustration of a traffic scene from a driver's perspective focused on a field of view display;

Figure 4 shows an illustration of a field of view display with a control device for operating a field of view display according to an embodiment of the invention;

Figure 5 shows an illustration of an autostereoscopic field of view display with a combiner according to an embodiment of the present invention;

Figure 6 shows an illustration of an autostereoscopic windshield display according to an embodiment of the present invention;

7 shows a schematic diagram of the relationship between image misalignment and convergence angle in an autostereoscopic field of view display according to an embodiment of the present invention;

8 shows a schematic diagram of the relationship between image misalignment and virtual image distance in an autostereoscopic field of view display according to an embodiment of the present invention;

FIG. 9 shows an illustration of a vehicle having a field of view display according to an embodiment of the present invention;

Figure 10 shows an illustration of a traffic scene from a driver's perspective in a field of view display according to an embodiment of the present invention;

Figure 11 shows a graphical representation of the comfort zone in the relationship between virtual image distance and projection distance in a field of view display according to an embodiment of the present invention;

12 shows a graphical representation of a reduced comfort zone in the relationship between virtual image distance and projection distance in a field of view display according to an embodiment of the present invention;

Figure 13 shows a flow chart of a method for operating an autostereoscopic field of view display according to one embodiment of the present invention; and

Figure 14 shows an illustration of the working principle of a method for operating an autostereoscopic field of view display according to an embodiment of the present invention.

Detailed ways

In the following description of advantageous embodiments of the invention, the same or similar reference numerals are used for elements that are shown in the different figures and function similarly, wherein a repeated description of these elements is omitted.

FIG. 1 shows an illustration of a vehicle 100 having a field of view display 102 . The field of view display 102 is designed as a front window display 102 . Here, the actual image 104 of the information to be displayed is produced in the region of the windshield 106 of the vehicle 100 . The image 104 is generated in the field of view of the observer 108 of the vehicle 100 , in this case the field of view of the driver 108 .

In the windshield display 102 or a transparent display 102 integrated separately in the vehicle that overlaps the driving scene, the image 104 displayed on the display 102 appears as a real image 102 on the windshield 106 or the separate glass - or in the area of the plastic windshield and not appearing as a virtual image at large distances (greater than 1.8 m) as in the HUD. As a result, when reading the image content on the windshield display 102 , the eyes of the driver 108 need to focus (accommodate) and rotate (convergence) from the driving scene to the windshield display 102 with greater effort than the HUD. . When the driver 108 observes the driving scene, the various optical axes of his eyes are nearly parallel, so that the target object in the vicinity (within 10 meters) is doubly displayed. If a nearby target object now consists of the image content 104 shown on the transparent display 102 , it may be doubly present and may have a disturbing effect.

FIG. 2 shows an illustration of a traffic scene 202 from a driver's perspective focused on a vehicle 200 traveling ahead. The traffic scene 202 is shown from the driver's perspective in FIG. 1 . The driver sees the traffic scene 202 forward through the windshield 106 . Here, the driver's right and left eyes are focused on the vehicle 200 traveling in front. However, not only the right eye but also the left eye collects the image 104 in the windshield 106 . Thus, the image 104 appears doubly as the right virtual image 204 and the left virtual image 206 .

FIG. 3 shows an illustration of a traffic scene 202 focused onto the field of view display 102 from a driver's perspective. The traffic scene 202 corresponds to the traffic scene in FIG. 2 . In contrast to this, the right and left eyes are here focused on the image 104 . However, not only the right eye but also the left eye picks up the vehicle 200 traveling in front. The preceding vehicle 200 thus appears doubly.

A windshield display 102 is shown in FIG. 1 with exemplary graphic content 104 , in this case a digital speed display 104 . If the driver 108 observes the driving scene, ie a distance in the range of approximately 10 m to 500 m, the image content 104 appears doubly, as shown in FIG. 2 . Conversely, if the driver observes the image content 104 of the windscreen display 102 , the driving scene 200 behind it appears doubly, as shown in FIG. 3 . This effect causes the eye in the windshield display 102 to frequently switch between hyperopia and myopia, which can be tiresome for extended periods of time.

If the image content 104 is displayed on the windscreen display 102 , it typically appears doubly when the driver 108 observes the target object 200 of the driving scene 202 , in this case the one driving ahead Vehicle 200. The image content 104 of the windshield display 102 is thus difficult to recognize in the peripheral field of view. Conversely, if the driver observes the image content on the windshield 106 (shown microscopically), the driver sees the driving scene 202 doubly.

In a transparent display 102 arranged near the main field of view, due to the small image distance, the following problem arises: when the driver 108 sees, for example, a vehicle 200 driving ahead on the display 102, he sees the transparent display doubly Image content 104 of 102 . Due to the convergence, the images 104 are laterally offset from each other. This is very disturbing when the image content 104 on the transparent display 102 is close to the driving situation 202 and also cannot be read out properly in the peripheral field of view - to some extent without direct viewing - because the image content 104 Flatly doubly manifest.

FIG. 4 shows an illustration of a field of view display 102 with a control device 400 for operating the field of view display 102 according to an embodiment of the invention. As in FIG. 1 , the field of view display 102 is installed in the vehicle 100 . In contrast to this, the field of view display 102 is designed here as an autostereoscopic head-up display 102 . The heads-up display 102 projects a right image 402 for the right eye of the observer 108 and a left image 404 for the left eye of the observer 108 . The projected images 402 , 404 are generated on the image sensor 406 of the head-up display 102 and reflected into the windshield 106 by a lens system 408 . The images 402, 404 are turned by the windshield 106 within the viewing area 410 where the eyes of the observer 108 are located. The images 402 , 404 are organized by the control device 400 so that the image content 412 appears stereoscopically at a predetermined distance to the observer 108 . For this purpose, the observer detects and in particular knows the position and the viewing direction of the eyes by means of the detection device 414 . Based on the position of the eye and the viewing direction or viewing axis, the misalignment between the right image 402 and the left image 404 is determined in order to obtain a stereoscopic effect.

An autostereoscopic head-up display 102 (HUD) is proposed here, which has an adapted display area which takes into account the current comfort zone of the driver 108 in terms of depth perception.

In the proposed solution, a special usage scenario of the autostereoscopic head-up display 102 (HUD) is discussed. As an important aspect it can be mentioned in this case that the (virtual) projection distances in the LCD screen and in the autostereoscopic HUD differ significantly from each other. Herein, the HUD 102 may be referred to as a see-through display (also referred to as a see-through display) or a field of view display. This display (unit) 412 is adjusted according to the user's fatigue state. In this case, the direction and internal rotation of the user's eyes are detected by means of the user's eye tracking device 414 , and the temporal changes in the viewing accommodation and its duration are known and taken into account in order to assess whether there is or is likely to be exploited by the driver 108 . Problems with display symbols on display unit 412 .

A head-up display 102 (HUD) is used to display driving-related information 412 (eg, speed indications, navigation information, warning indications, or more) in a viewing area 410 of the driver 108 . The virtual image 412 in which the information is shown is overlaid with the real environment.

In principle, the HUD 102 includes a light source, an image sensor unit 406 and a lens system 408 for imaging. Light exiting the system falls on the windshield 106 or a combiner-window mounted behind it, is partially reflected by the windshield or combiner-window and enters the driver's 108 eye 410, The driver perceives the virtual image 412 in front of him at a distance defined by the lens system 408 and a magnification also determined by the lens system.

As light sources, for example, LEDs or laser diodes can be used, which illuminate the LCD 406 from behind which provides the image content. Alternatively, different projectors can be used. Here, small projectors based on DMD technology, LCoS technology or laser technology can be used more in the future. In addition, efforts are made to realize the display of contact simulation. This contact-simulated display occupies a very large volume of construction space in binocular embodiments where both eyes view the same image. The binocular variant, in which the two eyes view slightly different images 402, 404 in each case, except for the stereoscopic depth perception (Tiefenempfindung) (“3-D effect”) In addition to the additional functions, outstanding advantages in terms of robustness, construction space and cost are also to be expected.

With the aid of an autostereoscopic HUD 102 (asHUD), driving-related information 412 can be shown in 3D without the driver 108 needing additional aids, such as blinded glasses or polarized glasses. Therefore, the driver 108 can always observe a perfect image 412 even when the head is in motion, the asHUD 102 requires: a head tracking system 414 that can analyze the driver's 108 head position and eye position 410; and corresponding tracker. A system overview of the principle structure of the asHUD system 102 is shown in FIG. 4 .

Figure 5 shows an illustration of an autostereoscopic field of view display 102 with a combiner 500 in accordance with one embodiment of the present invention. The field of view display 102 is installed in the vehicle as in FIGS. 1 to 4 . The image sensor 406 is illuminated by a light source. Right and left images are produced on the image sensor 406 . The combiner 500 reflects the reflected waves of the image sensor 406 towards the eyes of the observer 108 . The combiner 500 is arranged here at the lower edge of the windshield 106 . Thus, the combiner 500 is below the viewing axis 502 of the eyes of the observer 108 when the driver is looking into the distance. In other words, the combiner 500 is arranged in the peripheral field of view of the observer 108 . A virtual image 504 is formed in the projection plane 504 for the observer 108 in the region of the windshield 106 .

An embodiment is shown in FIG. 5 in which the image is imaged through a flat glazing 500 (or combiner-window) by means of a holographic projection glazing 406 that sinks in the instrument panel, directing radiation. Such an embodiment has the advantage that the system 102 can be used independently of the windshield 106 and the image is seen as a virtual image 504 behind the windshield 106, for example, due to the enlarged image The distance is comfortably perceived by the user.

In another embodiment, not shown, the image is projected directly onto a separate combiner-glass window, which then has, for example, a photopolymer layer with holographic scattering. In this case, the advantage of a widened image distance compared to windscreen displays is eliminated, for which reason the system is more space-saving and relatively uncomplicated, since the system consists of fewer components.

A variant of the “reflective display 102 ” shown in FIG. 5 is also conceivable, in which the image is not reflected through a separate window pane, but directly through the windshield 106 . The advantage of such an embodiment is that no additional components need to be installed in the instrument panel, and therefore the possibly interfering edges of the individual combiner 500 cannot be seen. In such an embodiment, an image that is evaluated as acceptable by the user is also formed when the smaller windshield is bent.

The stereoscopic display 102 may also be implemented as a combiner-display 102, as shown in this figure. A stereoscopic display 102 , which is also based on a holographic projection display 406 in this feature, can likewise be realized by such a combiner-display 102 . In this case, the holographic projection display 406 is opaque and is imaged by the planar combiner 500 . The image of the stereoscopic display 406 appears as a virtual image 504 . This has the advantage that there is a slightly larger image distance with respect to the driver's eyes than in the embodiment described below.

FIG. 6 shows an illustration of an autostereoscopic windshield display 102 in accordance with one embodiment of the present invention. The windshield display 102 may also be referred to as a field of view display 102 . In contrast to the field of view display in FIG. 5 , the right-hand and left-hand images are produced here in a projection area 600 or projection surface integrated into the windshield 106 . For this purpose, the two projectors 602 each project one of the images into the projection area 600 from below. In the projection area 600 , a holographic film 604 is arranged in or on the front window glass 106 . The membrane 604 forms a right viewing area 606 for the right eye of the observer 108 and a left viewing area 608 for the left eye. The right image is visible in the right viewing area 606 and the left image is visible in the left viewing area 608 . By lateral movement of the projector 602, the viewing areas 606, 608 can move laterally with the viewer 108.

In other words, a stereoscopic windshield display 102 with dynamic convergence matching means is proposed.

A preferred embodiment of the transparent display 102 is the windshield display 102 shown in FIG. 6 . Here, a photopolymer film 604 that implements a holographic scattering function is laminated into or onto the windshield 106 . By suitable combination with two separate image projectors 602, autostereoscopic image content can be produced as shown.

One embodiment of an autostereoscopic windshield display 102 is shown. The area 600 shown in dashed lines is a usable display surface 600 , which is illuminated by two projectors 602 . The holographically implemented transparent display 600 diffracts the image displayed by the first projector 602 into the first eye frame 606 and the image displayed by the second projector 602 into the second eye frame 608 . By lateral movement of the projector 602, the lateral position of the eye frames 606, 608 can be changed so as to follow the lateral head movement.

7 shows a schematic diagram of the relationship between image misalignment 700 and convergence angle 702 in an autostereoscopic field of view display 102 according to one embodiment of the invention. Here, the field of view display 102 is installed in the vehicle 100 , and the driver of the vehicle 100 sees the vehicle 200 traveling ahead via the field of view display 102 . Because the driver's right eye 704 is separated from the left eye 708 by an interocular distance 706, the visual axes 502 of the eyes 704, 708 have an angle of convergence 702 with respect to each other when both eyes 704, 708 are aligned at the same point 710. When the right image 402 and the left image 404 should appear stereoscopically at the point 710, the image misalignment 700 between the right image 402 and the left image 404 is the same as that between the eyes 704, 708 and the images 402, 404 The viewing distance 712, the distance 714 between the eyes 704, 706 and the point being viewed 710, and the eye separation 706 are related.

The angle of convergence 702 θ(Theta) may be the angle 702 between the visual axis 502 of the left eye 708 and the right eye 704, s may be the distance 712 from the driver's eyes 704, 708 to the windshield 106, and d may be The disparity 700 , ie the misalignment 700 of the images 402 , 404 shown stereoscopically on the windshield 106 , is shown so that the target 710 appears at a distance 714 z.

8 shows a schematic diagram of the relationship between image misalignment 700 and virtual image distance 714 in an autostereoscopic field of view display 102 according to one embodiment of the invention. The field of view display 102 here corresponds substantially to one of the field of view displays in FIGS. 4 to 6 . The images 402 , 404 are arranged in the same projection plane 504 . As shown, in both instances, as with the same offset 700 , the same viewing distance 712 , but with different reference numbers each, a different virtual image distance 714 results.

In the first example, the right image 402 is arranged to the right of the left image. The right eye 704 observes the right image 402 . Left eye 708 observes left image 404 . This creates the impression to the observer that the virtual image 412 will be farther away than the actual images 402 , 404 .

In the second example, the right image 402 is arranged to the left of the left image. Here, the right eye 704 also observes the right image 402 . The left eye 708 further observes the left image 404 . This creates the impression to the observer that the virtual image 412 would be arranged between the observer and the images 402 , 404 .

In other words, the principle of stereoscopic 3-D-viewing is shown in Fig. 8, which illustrates the virtual image distance 714 (VID for crossed (right) and non-crossed (left) viewing situations ) and the size of the virtual screen distance 712 (VSD).

The imaging lens system determines the virtual screen distance 712 (VSD) of the system 102 . The distance 714 (virtual image distance VID) in which the driver sees the image 412 can be selected by the horizontal offset 700 d of the two single images 402 , 404 on the display or at the virtual screen distance 712 VSD. The parameters - virtual screen distance 712 VSD and virtual image distance 714 VID - are shown in FIG. 8 for crossed and non-crossed viewing situations. The virtual image distance 714 VID is determined by the following formula,

where a represents the interocular distance 706 between the driver's pupils. The sign in the denominator determines whether the image 412 is located before or after the virtual screen distance 712 VSD. The system 102 can be matched to the eye separation 706 so that the driver can perceive the image information 412 at the desired distance 714 .

Because the driver's eye separation 706 is the indispensable information, which the system 102 needs in order to implement the image view 412 in such a way that it appears at the intended distance 714 for each driver, the system 102 is immediately able to measure The driver's eye distance 706 and the views 402, 404 are matched accordingly. With regard to the lower viewing angle, for example, the size of the driver is also taken into consideration. The cameras used for head tracking are then also used to acquire this information and to individually adapt the image views 402 , 404 to the driver. In addition, the driver can save his own priorities in terms of brightness, color, contrast or comfort zone.

FIG. 9 shows an illustration of a vehicle 100 having a field of view display 102 according to one embodiment of the present invention. The field of view display 102 substantially corresponds to the image display as shown in FIGS. 5 and 6 . The field of view display 102 is then a windscreen display 102 or a front window display 102 here. For the driver 108 , the right image 402 for the right eye 704 and the left image 404 for the left eye 708 are gradually revealed into the windshield 106 or the windshield 106 . The images 402 , 404 have an offset 700 with respect to each other because the driver 108 sees the driving scene in front of his vehicle 100 and therefore the viewing axes of the eyes 704 , 708 intersect behind the projection plane of the images 402 , 404 . The images 402 , 404 gradually appear distorted in perspective in order to obtain an undistorted image from the perspective of the driver 108 .

The transparent display device 102 can be realized by means of a volume hologram. The vehicle 100 may have a system for driver viewing that may detect the direction of the driver's 108 gaze.

In order to avoid double images, it is proposed to use a stereoscopic windscreen display 102 or to install it separately on the basis of the real-time knowledge of the convergence angles of the eyes 704 , 706 of the driver 108 in combination with a system for dynamic gap matching (Disparitätsanpassung) The stereoscopic transparent display 102 .

This requires a system for detecting the viewing direction that can reliably and in real time distinguish between at least two situations: "the driver 108 is watching the driving scene" and "the driver 108 is watching the image content 402, 404 of the transparent display 102" . If the driver 108 is viewing a driving scene, the gap 700 between the image content 402 , 404 shown on the windshield display 102 for each of the left eye 708 and the right eye 704 is adjusted such that double images are minimized. This corresponds to the stereoscopic movement of the image contents 402 , 404 into the viewing plane of the driver 108 . Conversely, if the driver 108 turns his gaze to the image content 402 of the windscreen display 102 , the image content is not shown stereoscopically, so that the driver 108 can also read the display, for example, as usual. each other vehicle display.

Additional eye position tracking is necessary in order to maintain the effect of autostereoscopic vision even when the driver's 108 head is moved sideways.

The image content 402 , 404 shown stereoscopically on the windshield 106 can be read out without a double image. The readout can be achieved without the convergence matching of the eyes 704 , 708 required when reading out conventional vehicle displays (eg instrument cluster). This results in time and comfort advantages when reading out the image content 402 , 404 , thereby ultimately improving driving safety. When the image content 402, 404 of the windshield display 102 is dimensioned accordingly, the image content can also be perceived and read in the peripheral field of view, so to speak without direct viewing. The size of the content 402, 404 shown may then be matched according to the smaller eye resolution in the peripheral field of view.

An autostereoscopic windshield display 102 is shown in FIG. 9 , however it shows the same image content 402 , 404 as in FIG. 1 in a stereoscopic manner. Here, the left eye 708 and the right eye 704 of the driver 108 each see one of the two target objects 402 , 404 shown offset from one another. When the driver 108 views the driving scene, the view by autostereoscopic does not form a double image.

Figure 10 shows an illustration of a traffic scene 202 from a driver's perspective in a field of view display 102 in accordance with one embodiment of the present invention. The traffic scene 202 corresponds substantially to the traffic scene in FIGS. 2 and 3 . Here it is shown that the driver as in FIG. 9 , although he observes the right image with his right eye and collects the left image with his left eye, sees a common undistorted virtual image 412 , which is in front of The moving vehicle 200 and its vehicle 100 appear floating.

If the image contents 402 , 404 are shown stereoscopically on the windscreen display 102 , the image contents 402 , 404 do not appear doubly when the driver looks at the target object 200 of the driving scene 202 . - in this case the vehicle 200 driving in front. Thus, the image content 402 , 404 can be read out in the peripheral field of view and presented undisturbed in this representation.

A solution to this problem is to display autostereoscopic image content 402, 404, which as long as the driver 108 is not viewing the transparent display 102, in such a way that the image content can be at least peripherally field of view to be read. When the driver is viewing the image content or the display directly, the autostereoscopic display is then switched off, since the display is uncomfortable for the eyes due to the small image distance.

11 and 12 show diagrams of comfort zone 1200 in a relationship between virtual image distance 714 and projection distance 712 or viewing distance 712 in a field of view display according to one embodiment of the invention. A comfort zone 1200 for each of the virtual images shown is described here in FIG. 11 . A comfort zone 1200 for a plurality of virtual images is shown in FIG. 12 , where the virtual images are shown at different distances 714 . In the comfort zone 1200, 75% of the observers perceive the viewing of the image content as comfortable. The comfort zone 1200 begins with a minimum distance 1202 from the viewer and ends with a maximum distance 1204 . Such a study is described in the publication "Exploring Design Parameters for a 3D Head-Up Display" mentioned at the outset, in which the limits of the comfort zone, described here only by way of example, are studied in detail.

The comfort zone 1200 here increases with increasing viewing distance 712 . In images shown at multiple distances simultaneously, the comfort zone 1200 is smaller than in the individual images. Additionally, the minimum spacing 1202 moves to a larger image distance 714 relative to each image in the case of multiple viewed images, while the maximum spacing 1204 becomes smaller.

Comfort zone 1200 is shown in FIG. 11 in relation to virtual image distance 714 VID and virtual screen distance 712 VSD for representing a virtual 3-D-target object. The comfort zone 1200 represents 75% of the subjects. In the area adjacent to comfort zone 1200, another 50% of the subjects are within their comfort zone.

Comfort zone 1200 is shown in FIG. 12 in relation to virtual image distance 714 VID and virtual screen distance 712 VSD for representing three virtual 3-D-target objects (front, middle, back). The middle area 1200 represents the comfort zone for 75% of the subjects. In the adjacent area, another 50% of the subjects were in their comfort zone.

In particular in the publication "Exploring Design Parameters for a 3D Head-UpDisplay" mentioned at the outset, it is described with the aid of an example value of the correlation consisting of the virtual image distance VID 714 and the virtual screen distance VSD 712 for HUD-applications Comfort Zone 1200. In addition, the front limit 1202 and the rear limit 1204 of the comfort zone 1200 are elaborated. A system with multiple (virtual) projection distances 714 is also the subject here.

Apart from the relationship reproduced by the formula presented in Figure 8, each person's 3-D-perception is individually different. Thus, each individual also has an individualized area in which the virtual image distance 714 VID can be moved at a certain virtual screen distance 712 VSD, for which comfortable 3-D viewing can be achieved. This area may be referred to as comfort zone 1200 . The comfort zone 1200 is decisively defined by the criteria of accommodation-convergence-conflict. If the comfort zone 1200 is exceeded, the driver may experience discomfort and discomfort (eg, eye pain, headache). The desired 3-D-perception may no longer be achieved.

Every type of physical discomfort, also a perceived loss of driving-related information, as shown by the asHUD, can create risks in road traffic and endanger not only the safety of the driver but also the safety of all other traffic participants.

An autostereoscopic HUD with an automatically adapted display area 1200 is proposed in the solution presented here. In this case, the display area is not only adapted to the respective driver, but also to his current physical and/or psychological situation. It is thereby avoided that the 3-D-display is outside the (current) comfort zone 1200 of the driver, thereby ensuring a comfortable perception for the driver and avoiding eye pain, headache or discomfort, This leads to an increase in the driving safety and pleasure factor.

The asHUD uses head-tracking data and other information captured by the head-tracking camera in order to adaptively match the size of the display area 1200 in which the image content is shown and the number of depth planes to the driver's current comfort Area 1200. This achieves a negative effect on the reduction of 3-D-displays, which may cause symptoms such as headache, eye pain, discomfort. Furthermore, the risk of image information not being merged is reduced. As a result, an extended service life can be achieved, since the comfort zone 1200 is limited, for example, when fatigued, for which the system must be switched off without an adaptive adaptation of the driver, since the perception in the display depends on it. say uncomfortable.

Furthermore, the driver is less fatigued, since the display is adapted to the driver in such a way that the driver is minimally fatigued. The display area 1200 can be individually adjusted in different ways for intersecting and non-intersecting viewing situations, ie the front bounds 1202 and the rear bounds 1204 of the display area 1200 can be changed independently. Drivers with a particularly large comfort zone 1200 can also use this comfort zone. The system can be adapted to different drivers/situations. It leads to the improvement of the experience factor, the improvement of safety and the improvement of comfort.

The comfort zone 1200 is closely related to the selected virtual screen distance 712 VSD. From the virtual screen distance 712 VSD a defined area 1200 of the virtual image distance 714 VID results in which information can be displayed so that the driver can perceive them comfortably. The area 1200 is examined in relation to the virtual screen distance 712 VSD. The results are qualitatively shown in FIGS. 12 and 13 . More precise values are described in "Exploring Design Parameters for a 3DHead-Up Display; Broy; Höckh; Frederksen et al; Pervasive Displays 2014". The comfort zone 1200 represents a zone that is perceived as comfortable by 75% of the subjects. Therefore, according to the virtual screen distance 712 VSD applied in the asHUD, a correspondingly adapted area 1200 should be selected within the lower limit 1202 VIDmin and the upper limit 1204 VIDmax of the virtual image distance 714 VID for displaying information. In systems that work with multiple virtual screen distances 712 VSD or even a variable virtual screen distance 712 VSD, care can also be taken when transforming or changing the virtual screen distance 712 VSD to match the virtual image distance 714 VID accordingly. Area 1200 displayed.

The comfort zone 1200 is of course not only related to the virtual screen distance 712 VSD, but also to the number of virtual image planes with different virtual image distances 714 VID for the display. The asHUD proposed here also includes the adaptation of the comfort zone 1200 in relation to the image content, in particular the number of virtual image surfaces applied.

Figures 11 and 12 only show the order of magnitude and general distribution of the comfort zone in relation to the VSD. Specific values are case-by-case, and details on basic research can be found in the aforementioned publications.

Furthermore, the empirically known values shown in Figures 11 and 12 are not valid for each driver, where there are large individual differences. Additionally, the driver's comfort zone 1200 may vary. Here, the following factors play a greater role: fatigue, contrast, age, visual defects, etc. Thus in another embodiment of the system, not only the virtual screen distance 712 VSD and the number of virtual faces are considered as described above, but also the driver's individualized, time-varying state.

In a simple embodiment, the driver can give feedback to the system as long as his comfort zone 1200 is compromised, that is to say as long as he is uncomfortable perceiving the current display. In this case, the input device can include, for example, rotary knobs, operating elements, steering wheel buttons, touch-screen displays or also voice- or gesture control devices. The input device here can be a simple input device, in which the driver can only reduce or expand the size of the comfort zone 1200 used, or a more complex input device, which enables the driver to use input The device directly adjusts the virtual image distance 714 the VID's front limit 1202 and back limit 1204 and/or the maximum number of depth planes.

In another embodiment the system is more complex. The system automatically recognizes when the driver's comfort zone 1200 is exceeded and automatically adjusts the comfort zone.

The driver's observations allow the display area 714 to be matched to the driver's current comfort zone 1200 . Information is obtained for this from the camera image of the head tracking system.

General fatigue can be detected by means of altered steering behavior or from camera images of the driver's face. Here, for example, gaze, eyelid closure frequency, eyelid closure duration, eye closure or yawning in percentage are taken into consideration. Therefore, the driver's fatigue state can be detected from this information of the steering angle sensor and by means of the head tracking camera. If fatigue is present, it is assumed in this case that the simplified diagram is displayed with a reduced display area 714 and fewer depth planes.

The reduction of the display area can be adjusted here, for example, in 20% steps (Schritt) with respect to the front limit 1202 (VIDmin is increased by 20%) and with respect to the rear limit 1204 in 10% steps (VIDmax is reduced by 10%) to adjust. The number of depth planes used at the same time can be reduced by one each. Reassess the driver behavior after each step and take another step if necessary. If a state is achieved in which the driver can again handle the HUD display without problems, this state is first maintained. The system can expand its display area 1200 again in various other directions with the same steps, if successive observations by the driver lead to the conclusion that it is becoming easier and easier for the driver to read the display.

The proposed system can not only learn the driver's viewing direction by means of the human eye tracking device, but also infer the convergence plane of the driver's viewing axis from the degree of rotation inside the two eyes. The duration of the observed image content and its change over time can thus be identified. In order to be able to detect the image content, it is necessary that not only the viewing direction but also the converging surfaces of the viewing axes also be suitable for the shown target object. If the duration is gradually increased until the driver achieves this persistent observation state, then the combined difficulty can be increased as a starting point. The system stores how long it takes for the driver until the direction of view and the convergence plane match, and how long it takes for the driver to see the displayed target object. If the time is atypically long for the individual driver or exceeds the previously defined absolute value or increases significantly with the age of use, the system reduces the comfort zone 1200 and the depth surface used as described above number of responses.

If the driver is not yet able to combine the images, the 3-D-mode is turned off. The system then works as a 2-D-HUD and can use see-through displays. The 3-D mode is switched on again after the next driving interruption or according to the driver's wishes. For this purpose, the driver may use the aforementioned input device if necessary.

The system uses the image content shown at each time to correct the data obtained by the driver's observations. This comparison informs which information is most interesting to the driver at that time. The information can then be arranged, for example, in the center of the field of view and in the center of the display area as long as it is not displayed in a touch-simulation manner, in each case being observed, for example, for one minute and then being able to react to this.

From the above, it can be found that the system proposed here is capable of matching the depth position (Tiefenposition) 714 of the image content and narrowly arranging the depth planes used and reducing their number in the following cases: all the above information is provided to the The system shows that the image content is currently outside the comfort zone 1200 for the driver. The goal here is to use only the driver's personalised momentary comfort zone 1200 . Then if the driver has been on the road for a long time, for example, and additionally or alternatively it gets dark and the driver becomes tired, his comfort zone 1200 becomes smaller. It may then become increasingly difficult for the driver to recognize the information shown at the smaller virtual image distance 714 VID. In this case, the driver needs more time to read out the information. The system reacts to this and zooms in on the minimum used virtual image distance 1202 VID until the system can determine that the driver no longer has difficulty using the asHUD with the automatically adapted display area.

Figure 13 shows a flowchart of a method 1500 for operating an autostereoscopic field of view display according to one embodiment of the present invention. The method 1500 has step 1500: adjusting the misalignment between the right image and the left image of the field of view display. Here, the misalignment is adjusted with the convergence angle between the right visual axis of the right eye and the left visual axis of the left eye of the observer using the visual field display. When the viewing axes intersect in the projection plane of the image, the image is adjusted without misalignment in sub-step 1502 .

In one embodiment, the method 1500 has a determining step 1504 . The step 1504 has a number of sub-steps 1504. In a first sub-step 1504 the viewing direction of the observer is determined. In a second sub-step 1504 the angle of convergence is determined. In a third sub-step 1504 the eye position is determined.

A distinction is made when determining the viewing direction: whether the observer is looking into the distance or whether the observer is looking at the field of view display. When determining the angle of convergence, the visual axes of the right eye and the left eye are evaluated taking into account the interocular distance of the eyes. In determining the position of the eyes, the distance between the eyes and the relative position of the eyes with respect to the field of view display are determined. When the observer looks into the distance, the misalignment is calculated using the convergence angle in calculation step 1506 , and the image is stereoscopically adjusted in adjustment step 1502 . When the viewer looks at the field of view display, the image is shown in an adjustment step 1502 without misalignment or microscopically.

Also in another calculation sub-step 1506, the position of the image on the field of view display is calculated in order to compensate for the observer's head movement.

In addition, in the adjustment step 1502, the image content is organized for the field of view display.

通过对差距进行匹配而移动到行驶场景中，以便清除另外出现的双重图像。此外获知驾驶员的眼睛位置，以便在驾驶员的头部侧向移动时在其位置方面根据深度指示、运动视差相应动态地匹配在行驶场景中以立体观测的方式移动的图像内容。The flowchart shows exemplary features of a display system according to the present invention. The driver viewing system, which is not described in detail, detects the viewing direction, the aforementioned convergence angle θ, and the driver's eye position. If the driver has set his eyes on the transparent display, its content is shown microscopically. If the driver watches the driving scene, the content of the transparent display is based on the given formula

Move to the driving scene by matching the gaps in order to clear up the additional double image. Furthermore, the position of the driver's eyes is known in order to dynamically adapt the image content moving stereoscopically in the driving scene with respect to its position as a function of the depth indication, the motion parallax, when the driver's head is moved laterally.

Figure 14 shows an illustration of the working principle of a method for operating an autostereoscopic field of view display 102 according to one embodiment of the present invention. In this case, the field of view display provides the observer 108 or the driver 108 with a right image 402 for the right eye and a left image 404 for the left eye. The observer 108 is recorded by the camera 414 of the driver monitoring system. The camera 414 provides camera images 1600 or video information 1600 . The camera image 1600 is evaluated in the control device 400 . In this case, the camera image 1600 is evaluated in a first evaluation device 1602 in order to match the image content to the field of view display 102 . Here, in particular the eye position 1604 and the eye's visual axis 1606 are evaluated and provided for further processing.

The camera image 1600 is evaluated in a second evaluation device 1608 in order to identify a comfort zone 1610 of the observer 108 . Here, the load state of the observer 108 is known by means of the bodily response. The comfort zone 1610 is related to the loading state.

Using the eye position 1604 and the visual axis 1606, a misalignment 700 between the right image 402 and the left image 404 is determined in the means 1612 for determining. The dislocation 700 between the images is adjusted in the means 1614 for adjustment by moving the displayed image content to the position determined by the dislocation. Image information 1616 on the right and image information 1618 on the left are provided here.

In the means for matching 1620, the right and left image information 1616, 1618 are matched using the comfort zone 1610. A misalignment 700 is defined if it is outside the comfort zone. The apparatus 1620 provides matched right image information 1622 and matched left image information 1624 for the field of view display 102 .

An adjustment loop is thus obtained, in which the reaction of the observer 108 can be decisively used to adjust the comfort zone 1610 .

In other words, FIG. 14 shows that the solution proposed here is incorporated into the working principle of the autostereoscopic head-up display 102 .

Here, relatively simple embodiments can be combined into relatively complex embodiments. The system 400 works automatically, but the driver can not only switch off the system, but also manually adapt it to his wishes, as in a simpler embodiment.

In another embodiment, the automated system is designed as a learning system so that the system learns and stores individual drivers and their typical adjustments and fatigue performance. Therefore, the ideal match can always be performed faster and more smoothly.

A schematic diagram showing the working principle of the asHUD 102 with comfort zone-matching.

The exemplary embodiments described and shown in the figures were chosen only by way of example. The different embodiments can be combined with each other in whole or with respect to individual features. An embodiment may also be supplemented by features of another embodiment.

Furthermore, the method steps presented herein may be performed repeatedly and in another order than that described.

If an example includes an "and/or" connection between a first feature and a second feature, this will be understood to mean that the example, according to one embodiment, has not only the first but also the second feature , and according to another embodiment either only the first feature or only the second feature.

Claims (11)

1. Method (1500) for operating an autostereoscopic field display (102) for a vehicle (100), wherein the method (1500) comprises the following steps:

adjusting (1502) a misalignment (700) between a right image (402) and a left image (404) of the heads-up display (102) using a convergence angle (702) between a right visual axis of a right eye (704) and a left visual axis of a left eye (708) of an observer (108) of the heads-up display (102), wherein the right image (402) and the left image (404) are adjusted without misalignment when the right and left visual axes intersect in a projection plane (504) of the right image (402) and the left image (404).

2. The method (1500) of claim 1, having the step (506) of: the positions of the right image (402) and the left image (404) in the projection surface (504) are determined using the visual axis and the eye position of the observer (108), wherein the determined positions are also adjusted in an adjustment (1502).

3. The method (1500) according to any of the preceding claims, having the steps of: the eye information is read in by an eye detection device (414) of the vehicle (100), which is designed to detect a right eye (704) and a left eye (708) of the observer (108), wherein the eye positions are imaged with right eye position values and left eye position values of the eye information, and the right visual axis and the left visual axis are imaged with right visual direction values and left visual direction values of the eye information, wherein the convergence angle (702) is determined from the visual direction values and the eye position values in the step of adjusting (1502).

4. The method (1500) according to claim 1 or 2, wherein in the step of adjusting (1502) the misalignment (700) is adjusted within a comfort zone (1200) associated with the observer.

5. The method (1500) of claim 4, having the step of matching the comfort region (1200), wherein the comfort region (1200) is matched in a manner that is responsive to an input by a user (108).

6. The method (1500) of claim 5, wherein in the step of matching, the comfort region (1200) is matched in relation to a number of depth planes to be displayed, wherein the comfort region (1200) is reduced when the number of depth planes increases.

7. The method (1500) according to claim 5, wherein in the step of matching the comfort region (1200) is changed in relation to the user, wherein the comfort region (1200) is reduced when the observer (108) is tired.

8. The method (1500) according to claim 7, wherein in the step of matching fatigue of the observer (108) is identified using eye information.

9. The method (1500) according to claim 8, wherein eyelid closure frequency and/or eyelid closure duration are evaluated.

10. Control device (400) designed to perform all the steps of the method (1500) according to any one of the preceding claims.

11. A machine-readable storage medium having stored thereon a computer program arranged to perform all the steps of the method according to any of the preceding claims 1 to 9.

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