DE102021103754A1 - Method and device for checking an augmented reality display on a head-up display device - Google Patents

Abstract

The invention relates to a method for evaluating a visual field display system for the augmented contact-analogous representation of an information object in a vehicle, with the following steps: - providing a contact-analogous display of an information object with respect to an environmental position that is assigned to an environmental object, by the visual field display system; - capturing a camera image by a visual field camera, which is arranged at a possible eye position and is aligned with a display area of the visual field display system;- extracting an environment image and an image of the information object from the camera image;- determining an actual representation of the information object from the image of the information object and specifying a desired representation of the information object - Determining an evaluation measure for the field of view display system depending on a representation accuracy, which results from the actual representation and the desired th representation results.

Description

technical field

The invention relates to field of view display devices and in particular to field of view display devices with devices for contact-analog display of information objects in relation to objects in the environment or positions in the environment. The invention also relates to measures for checking the correctness of the display of information objects to be displayed in a contact-analog manner on a visual field display device.

Technical background

Head-up display devices are used in particular in motor vehicles and are known in particular under the name head-up display (HUD). A desired display content, for example information about a speed limit or other useful navigation and vehicle operating instructions, can thus be superimposed in the form of a virtual display image on the real image of the surroundings in front of the vehicle observed by the driver. For this purpose, a visual field display device comprises a projection unit, which is usually installed in an instrument panel of the motor vehicle and which generates a projection light beam with the desired display content and transmits it by means of the windscreen of the vehicle or by means of an additional transparent combiner screen provided in front of it, from which it is reflected towards the driver projected his field of vision.

The implementation of augmented reality displays of virtual information objects on a visual field display device requires a very accurate and very fast tracking method for the eye pose of the driver or the vehicle occupant. During the display of information objects, compensatory movements must also be provided, which act on the vehicle along the trajectory driven by disruptive influences, in order to display the displayed contact-analog information objects in a stable, stationary manner in relation to a surrounding object or a surrounding position.

The quality of a contact-analog display on a head-up display device depends to a large extent on display fidelity and tracking speed on the display surface. Which display accuracy, i. H. which position deviations, size deviations and/or orientation deviations of the displayed information object compared to the target representation, and which tracking speeds are tolerable and which are not, determines the quality of the field of view display device, which cannot be predicted before implementation or can only be predicted unreliably. The correct evaluation of a representation of a contact-analogous information object on a display surface of a field of vision display device cannot be determined precisely due to a lack of feedback, since the actual eye position can only be determined with a corresponding degree of uncertainty due to numerous influencing factors.

The object of the present invention is to provide a method for evaluating a contact-analog representation of an information object on a display surface of a field of view display device, with which the actual quality of the contact-analog representation can be evaluated regardless of existing inaccuracies and tolerances of the display system.

Disclosure of Invention

This object is achieved by the method for determining a quality of a representation of an information object to be displayed contact-analogously on a display surface of a visual field display device according to claim 1 and by a device and a quality assessment system according to the independent claims.

Further developments are specified in the dependent claims.

• - Bereitstellen einer kontaktanalogen Anzeige eines Informationsobjektes bezüglich einer Umgebungsposition, die einem Umgebungsobjekt zugeordnet ist, durch das Blickfeldanzeigesystem;
• - Erfassen eines Kamerabildes durch eine Blickfeldkamera, die an einer möglichen Augenposition angeordnet und auf einen Anzeigebereich des Blickfeldanzeigesystems ausgerichtet ist;
• - Extrahieren eines Umgebungsbildes und eines Bildes des Informationsobjektes aus dem Kamerabild;
  • - Ermitteln einer tatsächlichen Darstellung des Informationsobjektes aus dem Bild des Informationsobjektes und Vorgeben einer gewünschten Darstellung des Informationsobjektes
• - Ermitteln eines Bewertungsmaßes für das Blickfeldanzeigesystem abhängig von einer Darstellungsgenauigkeit, die sich aus der tatsächlichen Darstellung des Informationsobjekts und der gewünschten Darstellung des Informationsobjekts ergibt.

According to a first aspect, a method for evaluating a visual field display system for the augmented contact-analogous representation of an information object in a vehicle is provided, with the following steps:

• - providing a contact-analogous display of an information object with respect to an environmental position, which is assigned to an environmental object, by the head-up display system;
• - capturing a camera image by a head-up camera placed at a possible eye position and aligned with a display area of the head-up display system;
• - extracting an environment image and an image of the information object from the camera image;
  • - Determining an actual representation of the information object from the image of the information object and specifying a desired representation of the information object
• - Determination of an evaluation measure for the field of view display system depending on a representation accuracy, which results from the actual representation of the information object and the desired representation of the information object.

It can be provided that the specification of the desired representation of the information object takes place depending on a detection of one or more surrounding objects, which are assigned to the information object, from the surrounding image. Alternatively, the desired representation of the information object can also be provided independently of an environment object.

Herein the representation of the information object includes the display position, the display size and/or the display orientation. The representation accuracy can indicate the positional deviations, size deviations and/or orientation deviations of the displayed information object compared to the target representation or in relation to specified positional deviations, size deviations and/or orientation deviations.

An idea of the above method is to arrange a head-up camera such that the field of view of the head-up camera substantially corresponds to the field of view of one or more eyes of a user of the head-up display device. For example, the visual field camera can be arranged on the user's glasses. By means of suitable optical devices, the field of view camera can capture a field of view that extends around the optical line of sight of an eye of the user or corresponds to the field of view of the user.

If the user looks at a display area of a visual field display device on which a contact-analogous information object is displayed, then the visual field camera captures an entire camera image that results from the superimposition of the environment with the displayed virtual information object.

An information object can be a text, a symbol, an object border, an image, a code such as e.g. B. include a QR code, or the like.

Furthermore, the environmental image and the image of the information object can be extracted from the camera image by displaying the information object in a specified display type and determining the image portion that is captured by the visual field camera in the specified display type as an image of the information object.

By providing a specific type of representation of the display of the contact-analog information object, the identification of the information object displayed in the camera image of the visual field camera can be facilitated. The representation type corresponds to a specific display property.

• - eine periodische oder regelmäßige Variation der Anzeigehelligkeit des Informationsobjekts;
• - eine periodische oder regelmäßige Variation einer Farbänderung des Informationsobjekts, insbesondere einer periodischen oder regelmäßigen Anzeige eines Inversbildes des Informationsobjekts oder einer periodischen oder regelmäßigen Anzeige eines farbverfremdeten Bilds des Informationsobjekts,
• - ein periodisches oder regelmäßiges Ausblenden der Anzeige des Informationsobjekts;
• - eine sich periodisch oder regelmäßig verändernde Polarisation des Informationsobjekts,
• - eine sich periodisch ändernde Position, Größe und/oder Orientierung des Informationsobjekts und dergleichen dargestellt werden;
• - eine Anzeige eines vorbestimmten Musters als das Informationsobjekt, das durch Vergleich mit einem Objektkatalog erkannt werden kann und sich von natürlichen Objekten der Fahrzeugumgebung ausreichend unterscheidet, und
• - eine Anzeige des Informationsobjekts mit Licht einer bestimmten Polarisation. (Es ist üblich, Frontscheiben auszubilden, die bevorzugt s-polarisiertes Licht reflektieren.)

The specified display type can include at least one of the following display types or display properties:

• - a periodic or regular variation of the display brightness of the information object;
• - a periodic or regular variation of a color change of the information object, in particular a periodic or regular display of an inverse image of the information object or a periodic or regular display of a color-altered image of the information object,
• - a periodic or regular hiding of the display of the information object;
• - a periodically or regularly changing polarization of the information object,
• - a periodically changing position, size and/or orientation of the information object and the like are displayed;
• - a display of a predetermined pattern as the information object, which can be recognized by comparison with an object catalog and is sufficiently different from natural objects of the vehicle environment, and
• - a display of the information object with light of a certain polarization. (It is common practice to design windscreens that preferentially reflect s-polarized light.)

Furthermore, a chronological sequence of the actual representation of the information object and the desired representation of the information object, in particular in the event of a relative movement between a surrounding object in the vicinity of the vehicle and the vehicle, can be recorded, with a tracking speed being calculated from the corresponding changes in the actual representation of the Information object and the changes in the desired representation of the information object is determined using an autocorrelation function, with the assessment criterion being determined as a function of the tracking speed determined. The time delay between the real-time display time of the target display of the information object and the actual display time of the display of the information object can be determined and evaluated here.

In the manner indicated above, it is possible to separate the image of the environment and the displayed information object from one another. By eval The quality of the contact-analogous display of the information object can now be assessed by processing the image of the environment for detecting and localizing objects in the environment and the position of the information object displayed in the camera image. At least the display accuracy of the displayed information object can be evaluated in relation to a specified target display of the information object with which a surrounding object is to be displayed. In the case of a dynamic observation over a certain period of time, the tracking speed can also be evaluated when the relative positions of the surrounding object, the vehicle and/or the head change. The change in relative positions occurs with movement of the surrounding object and/or movement of the vehicle (going straight, cornering, pitching, tilting and the like), movement of the head (which requires parallax compensation to be performed) and in other cases, in which the display of the information object has to be adjusted. An evaluation measure resulting from the display accuracy and possibly the tracking speed can be used to diagnose the quality of a display system with a visual field display device.

The tracking speed can take into account the delay in a change in position, a change in size and/or a change in orientation of the displayed information object.

• - eine Blickfeldkamera, die an einer möglichen Augenposition eines Benutzers angeordnet ist und auf einen Anzeigebereich des Blickfeldanzeigesystems ausgerichtet ist;
• - eine Steuereinheit, die ausgebildet ist, um:
  • ◯ das Blickfeldanzeigesystem zu veranlassen, eine kontaktanaloge Anzeige eines Informationsobjektes bezüglich einer Umgebungsposition, die einem Umgebungsobjekt zugeordnet ist, bereitzustellen;
  • ◯ ein gesamtes Kamerabild mit der Blickfeldkamera zu erfassen;
  • ◯ ein Umgebungsbild und ein Bild des Informationsobjektes aus dem Kamerabild zu extrahieren;
  • ◯ eine tatsächliche Darstellung des Informationsobjektes aus dem Bild des Informationsobjektes zu ermitteln und eine gewünschte Darstellung des Informationsobjektes vorzugeben;
  • ◯ ein Bewertungsmaß für das Blickfeldanzeigesystem abhängig von einer Darstellungsgenauigkeit, die sich aus der tatsächlichen Darstellung des Informationsobjekts und der gewünschten Darstellung des Informationsobjekts ergibt, zu ermitteln.

According to a further aspect, there is provided an evaluation system for evaluating a head-up display system, comprising:

• - a head-up camera arranged at a possible eye position of a user and aligned with a display area of the head-up display system;
• - a control unit designed to:
  • ◯ cause the head-up display system to provide a contact analog display of an information object related to a environmental position associated with a environmental object;
  • ◯ capture an entire camera image with the line-of-sight camera;
  • ◯ extract an image of the surroundings and an image of the information object from the camera image;
  • ◯ determine an actual representation of the information object from the image of the information object and specify a desired representation of the information object;
  • ◯ to determine an evaluation measure for the visual field display system depending on a representation accuracy that results from the actual representation of the information object and the desired representation of the information object.

character list

• 1 eine schematische Darstellung eines Anzeigesystems einer Blickfeldanzeigevorrichtung in einem Kraftfahrzeug und eines Bewertungssystems zur Bewertung einer Anzeigequalität des Anzeigesystems;
• 2 eine beispielhafte Darstellung eines Kamerabilds; und
• 3 zeigt ein Flussdiagramm zur Veranschaulichung eines Verfahrens zur Bewertung eines Anzeigesystems mit einer Blickfeldanzeigevorrichtung.

Embodiments are explained in more detail below with reference to the accompanying drawings. Show it:

• 1 a schematic representation of a display system of a head-up display device in a motor vehicle and an evaluation system for evaluating a display quality of the display system;
• 2 an exemplary representation of a camera image; and
• 3 FIG. 12 shows a flow chart for illustrating a method for evaluating a display system with a head-up display device.

Description of Embodiments

1 shows a schematic cross-sectional view through a visual field display system 1 with a head-up display device 2. The head-up display device 2 comprises a projection device 21 for emitting a projection light beam P with image information and a transparent cover 22. The projection beam P is directed at a display area A of a windshield 5 of a motor vehicle, so that it is reflected there in an eye area 8 (eye box) of the driver.

The cover 22 serves to protect the projection device 21 from external influences, in particular from contamination. The cover 22 of the projection device 21 has a cover plate 25 and is preferably curved in order to focus incident ambient light and to reflect it in a targeted manner.

The head-up display device 2 is essentially inserted into an opening in a top side 6 of an instrument panel 4 between a steering wheel and a windshield 5 of a motor vehicle in such a way that it ends essentially flush with the top side 6 or is adjacent to it.

The projection device 21 comprises in a known manner an optical system of one or more mirrors 23, optionally lenses (not shown) and a projector 24 or the plurality of mirrors 23 are aligned in the projection direction and projected onto the display area A. The projection light beam bundle P reflected in the display area A into the driver's eye is used to display corresponding information for the driver.

1 FIG. 12 further shows a schematic representation of an evaluation system 30 which is connected to the head-up display system 1 and a head-up camera 31 . The evaluation system 30 should make it possible to evaluate a display of a virtual information object in the display area A with regard to display accuracy and tracking speed. This is particularly useful if contact-analogous information objects are to be displayed in the display area A. Contact-analogous information objects are representations that are associated with a specific environmental position or a specific environmental object from the point of view of the observer who is looking through the display area at the area surrounding the vehicle. If, for example, the surrounding object moves relative to the vehicle, this is perceived by the viewer at a changing position through the display area A. The contact-analogous information object is tracked on the display area A according to the changing perception position.

To evaluate the head-up display system with the head-up display device, an eye position of a vehicle occupant, in particular in the eye area 8 of a vehicle occupant (driver) sitting on a vehicle seat, a head-up camera 31 can be provided, which is aligned in the direction of the display area A of the head-up display device 2. For this purpose, the visual field camera 31 is located at a possible eye position or close to a possible eye position and thus captures an entire camera image that is perceived by a user who is looking at the display area. Provision can also be made for the camera to be located precisely in the eye position(s). For this purpose, a structure with data glasses and a visual field camera 31 attached thereto can be provided, with the detection of the visual field camera 31 being brought directly in front of the eye position(s) by means of at least one semitransparent mirror.

The field of view camera 31 may be mounted at an appropriate position in the eyebox or attached to smart glasses 32 worn by a user seated in the vehicle. The representation quality of the contact-analogous display of the information object in the display area A is evaluated using the evaluation system 30 , which is in communication with the visual field display system 1 .

The evaluation system 30 is designed to detect one or more temporally consecutive camera images of the visual field camera 31 . The camera image recorded by the visual field camera 31 corresponds to an entire camera image from a superimposition of the perception of the vehicle surroundings (image of the surroundings) with the information object displayed in a contact-analogous manner. The evaluation system 30 is designed to recognize the displayed information object in the entire camera image and to separate it from the image of the surroundings. This makes it possible for the captured entire camera image to be divided into an image of the surroundings and an image of the information object.

2 shows a schematic representation of an entire camera image G from an environmental image with environmental objects U and an information object O for display with a position reference to the environmental object U. The information object O overlays the perception of the environment. The size of the entire camera image G corresponds to part or all of the display area A.

The surrounding object is located at an object position OP, while the information object U is to be displayed correspondingly at a display position, superimposed on the environment. The display position may be offset from the object position or entirely or partially overlay or entirely or partially surround the surrounding object.

The evaluation system 30 now evaluates the representation fidelity/representation accuracy of the displayed information object O with reference to the surroundings, in particular with reference to one or more surrounding objects O, which can be recognized in the entire camera image G. By repeatedly determining the display accuracy of the displayed information object O in relation to a surrounding object U assigned to the information object O on sequentially recorded camera images, a tracking speed of the display of the displayed information object O to the display of the surrounding object U can be increased for a moving vehicle and/or a moving environmental object U can also be determined, for example, by applying an autocorrelation function.

The autocorrelation function results in a time offset that specifies the delay with which the display of the information object is displayed with a delay in relation to the desired display of the information object in relation to real time.

The representation accuracy and the tracking speed can be converted into an evaluation measure according to an evaluation function which can be used for diagnosis and quality assessment of the head-up display system 1.

The information object O can be recognized or extracted from the entire camera image G using conventional pattern recognition methods. However, in order to facilitate recognition, the information object O can be represented with an image property that enables the evaluation system to separate the information object O from the surrounding image in a simple manner. For this purpose, the evaluation system 30 can control the visual field display system 1 accordingly. For example, the information object O can also be displayed according to a periodic display pattern. For example, periodic color changes or an inverse representation of the information object can enable a clear differentiation between the information object O and the one or more surrounding objects U or the surrounding image. A periodic change in brightness, in particular the periodic interruption of the display of the information object O, can also be carried out for a short period of time that cannot be perceived by a viewer. Pixels of the entire camera image that have such a display pattern can then be assigned to the information object O.

The information object can also be displayed in polarized light and detected separately by a separate field of view camera or a switchable polarization filter in front of the field of view camera 31, so that by subtracting camera images from an image recorded without a polarization filter and an image recorded with a polarization filter, the surrounding image and the image of the Information object can be obtained.

In particular, two field of view cameras can be provided, the viewing angles of which are superimposed using a semi-transparent mirror, one of the field of view cameras being provided with a polarization filter. The visual field camera 31 without the polarization filter can then record the entire camera image, while the visual field camera 31 provided with the polarization filter (same polarization type as the displayed information object) does not perceive the displayed information object and only records the surrounding image. As a result, the representation of the information object O can be extracted from the perception of the surroundings by subtracting the two camera images.

In 3 a flowchart for illustrating a method for operating the evaluation system 30 is shown schematically.

In step S1, the contact-analog display of an information object O in the display area of the head-up display system 1 is started. For the contact-analogous display of the information object, an eye pose of a user is detected by the control unit 25 of the visual field display system 1 and the information object is displayed at a display position in the display area A, which results from the user's eye position and an environmental position, which can be specified or related to the position of a recognized object in the surroundings is determined. In particular, a desired representation of the information object O is determined from the environmental position, which is offset from the environmental position, for example, in order to display the contact-analogous information object O next to the relevant environmental position or next to the recognized environmental object U. The information object O is then ideally displayed in the display area A at the intersection of a line of sight between the eye position and the display position.

The display of the information object O is continuously updated so that the display position of the information object O on the display area A is tracked when the vehicle and/or a moving surrounding object U and/or a changing head pose or eye position is moving.

In step S2, the field of view camera 31 first records the display area A and the camera image of an image of the surroundings and an information object O superimposed thereon.

Using one of the methods described above, the image of the information object O can be separated or extracted from the camera image in step S3. This can be done by recognizing a type of representation of the information object O. For this purpose, the evaluation system 30 controls the control unit 25 of the visual field display system 1 accordingly in order to output the information object according to the type of representation. From the image of the information object O, the actual representation of the information object O, i. H. at least its display position but also, if necessary, its display size and display orientation are determined.

In step S4, a surrounding object U to be identified, for which the information object O is to be displayed contact-analogously, is recognized from the surrounding image using known pattern recognition methods and the object position of the surrounding object is determined accordingly using known methods. Alternatively, a surrounding position can also be specified.

In step S5, the display position and, if necessary, the display size and/or the display orientation of the information object to be displayed are determined from one or more object positions or from a surrounding position according to a predefined display specification. The display position can completely or partially overlay one of the object positions or the environmental position or have a predetermined offset to one of the object positions.

In step S6, a desired representation (target representation) of the information object O is determined based on an eye position, which the evaluation system can obtain from the control unit 25 of the head-up display system 1 . The desired display can include at least one of the following: the target display position, the target display size, the target display orientation

In step S7, the deviation of the actual display (display position, display size, display orientation) and the desired display (target display position, target display size, target display orientation) is determined as a display accuracy and this is evaluated accordingly with a rating. Overall, the quality of the field of view display system 1 can be assessed better the smaller the deviations from the desired representation with regard to the display position, the display size and the display orientation.

By repeatedly determining the deviation from the specified reference value, a course of the representation accuracy can be determined, in particular in the case of a surrounding object moving relative to the vehicle. The tracking speed can be determined, for example, by applying an autocorrelation function between the change in the actual representation and the change in the desired representation of the information object O in question. The autocorrelation function results in a time offset (delay time) which indicates the delay with which the display of the information object is displayed with a delay in relation to the desired display of the information object O in relation to real time.

From the display accuracy for a static surrounding object U or from a mean value of the display accuracy for a moving surrounding object U and the determined tracking speed, an evaluation measure can be determined using an evaluation function, which indicates the quality of the visual field display system 1 . The evaluation measure can take into account at least one of the following variables, in particular weighted: the deviations in the display position, the deviation in the display size, the deviation in the display orientation at one or more points in time, the level of the mean value of the above deviations (real or absolute), the time offset with regard to display position, display size and display orientation.

This evaluation measure can be signaled in step S8 and can also be used for a diagnosis of the display system, so that an error is signaled if the evaluation measure indicates an excessive deviation in the display accuracy and/or the tracking speed.

For automation, both information objects and environmental objects U can be evaluated and compared with one another using computer vision software.

Reference List

1

head-up display system

2

Head-up display facility

21

projection device

22

transparent cover

23

mirror

24

projector

25

control unit

4

dashboard

5

windscreen

6

top

30

Rating System

31

field of view camera

32

data glasses

O

information object

u

environment object

Claims (10)

Method for evaluating a visual field display system (1) for the augmented contact-analogous representation of an information object (O) in a vehicle, with the following steps: - Providing (S1) a contact-analogous display of an information object (O) with respect to an environmental position assigned to an environmental object (U). is, through the head-up display system (1); - capturing (S2) a camera image by a head-up camera (31) arranged at a possible eye position and aimed at a display area of the head-up display system (1); - Extracting (S3) an image of the surroundings and an image of the information object from the camera image; - determining (S5, S6) an actual representation of the information object (O) from the image of the information object (O) and specifying a desired representation of the information object (O); and - determining (S7, S8) an evaluation measure for the field of view display system (1) as a function of a display accuracy which results from the actual display and the desired display. procedure after claim 1 , wherein the specification of the desired representation of the information object (O) depends on a detection of one or more surrounding objects (U) that are assigned to the information object (O) from the surrounding image. procedure after claim 1 or 2 , wherein the representation of the information object includes the display position, the display size and/or the display orientation. Procedure according to one of Claims 1 until 3 , wherein the display accuracy indicates the position deviation, size deviation and/or orientation deviation of the displayed information object (O) in comparison to predetermined position deviations, size deviation and/or orientation deviation. Procedure according to one of Claims 1 until 4 , wherein the environmental image and the image of the information object (O) are extracted from the camera image by displaying the information object (O) in a specified representation type, and the image portion that is captured by the visual field camera (31) in the specified representation type , is determined as the image of the information object (O). procedure after claim 5 , wherein the specified type of representation comprises at least one of the following types of representation: - a periodic or regular variation of the display brightness of the information object; - A periodic or regular variation of a color change of the information object (O), in particular a periodic or regular display of an inverse image of the information object (O) or a periodic or regular display of a color-altered image of the information object (O); - A periodic or regular hiding of the display of the information object (O); - A periodically changing position, size and/or orientation of the information object (O) and the like are displayed; - a display of a predetermined pattern as the information object, which can be recognized by comparison with an object catalog and is sufficiently different from natural objects in the vehicle environment, and - a display of the information object with light of a specific polarization. Procedure according to one of Claims 1 until 6 , wherein a chronological sequence of the actual representation of the information object (O) and the desired representation of the information object (O), in particular in the case of a relative movement between a surrounding object in the vicinity of the vehicle and/or the vehicle and/or the possible eye position is recorded, wherein a tracking speed is determined from the corresponding changes in the actual representations and the changes in the desired representations of the information object (O), in particular with the aid of an autocorrelation function, the evaluation measure being determined as a function of the tracking speed. procedure after claim 7 , wherein the tracking speed takes into account the delay in a change in position, a change in size and/or a change in orientation of the displayed information object (O). Procedure according to one of Claims 1 until 8th , whereby the assessment measure takes into account at least one of the following variables, in particular weighted: the deviations in the display position, the deviation in the display size, the deviation in the display orientation at one or more points in time, the height of the mean value of the above deviations (real or absolute), the time offset in terms of display position, display size and display orientation. An evaluation system for evaluating a head-up display system (1), comprising: - a head-up camera (31) arranged at a possible eye position of a user and aimed at a display area of the head-up display system; - A control unit that is designed to cause the visual field display system to provide a contact-analogous display of an information object with respect to an environmental position that is associated with an environmental object; ◯ capture a camera image with the visual field camera (31); ◯ to extract an environment image and an image of the information object (O) from the camera image; ◯ to determine an actual representation of the information object (O) from the image of the information object (O) and a desired representation of the information object (O) to specify; ◯ to determine an evaluation measure for the head-up display system depending on a positioning accuracy that results from the actual display position and the desired display position.

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