Method and device for spatially reconstructing an eye and determining a viewing vector of the eye

Abstract

The invention relates to a method (500), in particular for operating smartglasses (400), comprising the following steps: scanning (504) an eye (2) with a laser beam (20a, 22a), for example an infrared laser beam, in particular a modulated infrared laser beam, generated by means of an illumination device (100), in at least one dimension, wherein, depending on at least one emission angle (α), a point (20c, 22c) on a surface of the eye (2) is illuminated by the laser beam (20a, 22a), in particular in two dimensions, wherein, depending on a first emission angle (α) and a second emission angle (β), a point (20c, 22c) on a surface of the eye (2) is illuminated by the laser beam (20a, 22a); detecting (506) the illuminated point (20c, 22c) on the eye (2) by means of an event camera (200); determining (508) a receiving position (20e, 22e) for the detected point (20c, 22c) at the event camera (200); determining (510) a distance value (z) of the illuminated point (20c, 22c) which characterizes a distance (z) between the surface of the eye (2) and an optically effective arrangement comprising the illumination device (100) and the event camera (200), depending on the at least one emission angle (α), the receiving position (20e, 22e) and a geometry of the optically effective arrangement, in particular by means of triangulation depending on a base distance (B) between the illumination device (100) and the event camera (200) specified by the geometry.

Description

[0001] Description

[0002] title

[0003] Method and device for the spatial reconstruction of an eye and determination of a gaze vector of the eye

[0004] State of the art

[0005] The present invention relates to a method and a device for the spatial reconstruction of an eye and for determining a gaze vector of the eye.

[0006] To estimate the pupillary ellipse of an eye, state-of-the-art methods employ scanning laser systems with a photodiode integrated into the laser system or externally. In this process, the pupillary contour of the eye appears light or dark. An image processing algorithm detects the dark or light pupillary contour in an image from the photodiode and estimates the pupillary ellipse. The photodiode is evaluated at a fixed sampling rate at asynchronous intervals.

[0007] Alternatively, the eye is illuminated using infrared LEDs arranged in a spectacle frame, with a photo camera sensor and an event camera capturing the eye to determine the eye's direction of gaze.

[0008] The aforementioned methods require complex image processing of the photodiodes or camera sensor, as well as matching the image processing rate to the laser system or illumination. This results in high computational effort and energy consumption. Furthermore, photodiodes and camera sensors are highly susceptible to stray light. Therefore, a method and device for determining a viewing vector are desirable that reduce computational complexity and energy consumption and are more robust against interference.

[0009] Disclosure of the invention

[0010] This is achieved by a device, a method and data glasses according to the independent claims.

[0011] The method, in particular for operating smart glasses, comprises: scanning an eye with a laser beam generated by means of a lighting device, for example an infrared laser beam, in particular a modulated infrared laser beam, in at least one dimension, wherein, depending on at least one beam angle, a point on a surface of the eye is illuminated with the laser beam, in particular in two dimensions, wherein, depending on a first beam angle and a second beam angle, a point on a surface of the eye is illuminated with the laser beam; capturing the illuminated point on the eye by means of an event camera;Determining a receiving position of the captured point on the event camera and determining a distance value of the illuminated point, which characterizes a distance between the surface of the eye and an optically effective arrangement comprising the lighting device and the event camera, depending on the at least one beam angle, the receiving position and a geometry of the optically effective arrangement, in particular by means of triangulation depending on a base distance between the lighting device and the event camera specified by the geometry.

[0012] Using the event camera allows for an increased sampling rate with the lighting system, as it eliminates dependence on a frame rate. Furthermore, computational complexity is reduced because processing a traditional camera sensor is no longer necessary. The event camera also improves robustness against ambient light and the risk of the smart glasses shifting. The modulated laser beam enables synchronization between the laser beam's modulation and the timing of events captured by the event camera, allowing for easy correction of interference. Ambient light and false events are easily identifiable through this synchronization. Triangulation allows for quick and easy determination of the eye's surface contours. Consequently, image quality, energy consumption, and robustness are all improved.An optically effective arrangement within the meaning of this disclosure is to be understood as meaning that it is not an actual position of the event camera and lighting equipment that is to be taken into account, but rather a virtual representation of these, if corresponding beam paths are influenced by, for example, lenses, mirrors, holograms, prisms or other optical elements.

[0013] Preferably, the method comprises approximating a spatial model of the eyeball based on a plurality of determined distance values ​​and at least one beam angle from corresponding illuminated points. The distance value and the beam angle are rapidly acquired by the event camera and the lighting device, thereby improving the dynamics of the approximation of the spatial model of the eyeball.

[0014] Preferably, the method comprises classifying the point into at least two clusters based on the determined distance value or a shape of the illuminated point captured by the event camera, wherein the at least two clusters include one cluster for points located on the cornea of ​​the eyeball and one cluster for points located on the sclera of the eyeball. This improves the approximation of the spatial model of the eyeball.

[0015] Preferably, the method comprises determining an approximation of the cornea and sclera of the eyeball based on the classified points, in particular by a sphere for the cornea and a sphere for the sclera; determining the spatial position of a center point of the corneal approximation and a center point of the sclera approximation; and determining a spatial gaze vector of the eye based on the spatial positions of these centers. The corneal and sclera approximations are improved in accuracy by classifying the points. Furthermore, separately determining the corneal and sclera approximations allows the use of simple geometric shapes as approximation approaches. The eye's gaze vector is thus determined with high dynamics.Furthermore, the use of the two approximations, which together also represent a spatial model of the eyeball, improves the accuracy of determining the gaze vector.

[0016] Preferably, the method comprises deflecting the laser beam emitted by the illumination device onto the eye by means of a first diffractive deflection device adapted to a wavelength of the laser beam, in particular by means of a holographic-optical element. The deflection device allows for flexible arrangement of the illumination device.

[0017] Preferably, the method comprises deflecting a beam path from the illuminated point onto the event camera by means of a second diffractive deflection device adapted to the wavelength of the laser beam, for example, by means of a holographic optical element. The second deflection device allows for flexible positioning of the event camera. Due to its diffractive property, only beams originating from the laser beam are deflected onto the event camera, thereby improving robustness.

[0018] The device comprises a lighting device designed to scan an eye with a laser beam generated by the lighting device, for example an infrared laser beam, in particular a modulated infrared laser beam, in at least one dimension, and to illuminate a point on a surface of the eye with the laser beam depending on at least one beam angle, in particular to scan in two dimensions, and to illuminate a point on a surface of the eye with the laser beam depending on a first beam angle and a second beam angle;an event camera configured to detect the illuminated point on the eye and to determine a receiving position of the detected point, and an evaluation device configured to determine a distance value of the point, which characterizes a distance between the surface of the eye and an optically effective arrangement comprising the lighting device and the event camera, depending on the at least one beam angle, the receiving position and a geometry of the optically effective arrangement, in particular by means of triangulation depending on a base distance between the lighting device and the event camera specified by the geometry.

[0019] Preferably, the evaluation device is designed to approximate a spatial model of the eyeball depending on a multitude of determined distance values ​​and at least one beam angle from correspondingly illuminated points.

[0020] Preferably, the evaluation device is designed to classify the illuminated point into at least two clusters depending on the determined distance value or shape of the point on the event camera, wherein the at least two clusters are one cluster for points that lie on a cornea of ​​the eyeball and one cluster for points that lie on the sclera of the eyeball.

[0021] Preferably, the evaluation device is configured to determine an approximation of the cornea of ​​the eyeball and an approximation of the sclera of the eyeball depending on the classified points, in particular by a sphere for the cornea and a sphere for the sclera; to determine a spatial position of a center point of the approximation of the cornea and a spatial position of a center point of the approximation of the sclera and to determine a spatial gaze vector of the eye depending on the spatial positions of the centers.

[0022] Preferably, the device comprises a first diffractive deflection device adapted to a wavelength of the laser beam, in particular a holographic-optical element, which is configured to deflect the laser beam emitted by the illumination device towards the eye.

[0023] Preferably, the device comprises a second diffractive deflection device, in particular a holographic-optical element, adapted to a wavelength of the laser beam and configured to deflect a beam path from the illuminated point onto the event camera. The smart glasses comprise the device according to the above embodiments, wherein, in particular, the illumination device and / or the event camera and / or the evaluation device are arranged in a frame and / or in a temple of the smart glasses.

[0024] Preferably, the first deflection device and / or the second deflection device is arranged in a lens of the data glasses.

[0025] Further advantageous embodiments will become apparent from the following description and the drawing. The drawing shows:

[0026] Figure 1 shows a schematic representation of a device for determining the gaze vector of an eye;

[0027] Figure 2 shows a schematic representation of a distance value depending on at least one beam angle;

[0028] Figure 3 shows a schematic representation of a cluster of determined distance values;

[0029] Figure 4 is a schematic representation of the eye;

[0030] Figure 5 shows a schematic representation of a spatial approximation of the eye, as well as an approximation of a cornea and an approximation of a sclera;

[0031] Figure 6 is a schematic representation of an embodiment of the device arranged in a pair of data glasses;

[0032] Figure 7 is a schematic representation of an embodiment of the device arranged in the data glasses;

[0033] Figure 8 shows a flowchart of a method for determining the gaze vector, in particular for operating the data glasses; Figure 9 shows a flowchart of part of an embodiment of the method;

[0034] Figure 10 shows a flowchart of part of an embodiment of the method.

[0035] Figure 1 shows a device 600 for determining a gaze vector of an eye 2. The device 600 comprises a lighting device 100, an event camera 200 and an evaluation device 300.

[0036] The illumination device 100 is configured to scan the eye 2 with a laser beam 20a, 22a generated by the illumination device 100, for example an infrared laser beam, in particular a modulated infrared laser beam, in at least one dimension. The laser beam 20a, 22a is, for example, modulated with a frequency of 1 MHz.

[0037] The lighting device 100 is designed to illuminate a point 20c, 22c on a surface of the eye 2 with the laser beam 20a, 22a depending on at least one beam angle a.

[0038] Preferably, the illumination device 100 is configured to scan the eye 2 in two dimensions and, depending on a first beam angle a and a second beam angle β, to illuminate the point 20c, 22c on the surface of the eye 2 with the laser beam 20a, 22a. Depending on the beam angle a and beam angle β, a different point 20c, 22c on the eye 2 is illuminated.

[0039] The lighting device 100 scans the eye, for example, with a Lissajous pattern or, instead of a row or column pattern, with a diagonal pattern.

[0040] The event camera 200 is designed to detect the illuminated point 20c, 22c on eye 2 and to determine a receiving position 20e, 22e of the detected point 20c, 22c. The event camera 200 includes, for example, an imaging optic 202 which projects a beam path 20d, 22d of the illuminated points 20c, 22c onto a sensor chip of the event camera 200. The evaluation device 300 is designed to determine a distance value z of the point 20c, 22c, which characterizes a distance z between the surface of the eye 2 and an optically acting arrangement comprising the lighting device 100 and the event camera 200, depending on the at least one beam angle a, the receiving position 20e, 22e and a geometry of the optically acting arrangement, preferably by means of triangulation depending on a base distance B between the lighting device 100 and the event camera 200 specified by the geometry.

[0041] The term "optically effective arrangement" does not refer to the actual arrangement of the lighting device 100 and the event camera 200, but rather, in the case that a beam angle of the lighting device 100 and / or the event camera 200 is deflected by optical elements such as holograms, lenses, mirrors, waveguides or prisms, a virtual image of the lighting device 100 and the event camera 200.

[0042] By modulating the laser beam 20a, 22a, the times of events occurring in the event camera 200, for example by detecting the illuminated points 20c, 22c, can be correlated with the modulated laser beam 20a, 22a. This allows interference from ambient light and false events in the event camera 200 to be suppressed, thus making the device 600 more robust.

[0043] Preferably, the evaluation device 300 is configured to approximate a spatial model of an eyeball 4 of the eye 2 depending on a plurality of determined distance values ​​z and at least one beam angle α of correspondingly illuminated points 20c, 22c. For example, known anatomical dimensions of the eye 2 and mathematical models can be used as a starting point for the approximation of the spatial model.

[0044] Figure 2 shows an example of the relationship between the distance value z and the radiation angle α and the radiation angle β in a one-dimensional representation. This relationship can be divided into different regions, each characterized by a region of the eye 2. For example, outer regions of the relationship represent the sclera of the eye 2, and inner regions represent the cornea 8 of the eye 2.

[0045] Figure 3 shows an example of a probability distribution P(z) of the distance value z. The probability distribution P(z) illustrates the probability that a distance value z of an illuminated and detected point 20c, 22c on the surface of eye 2 lies on the cornea 8 or the sclera 6 of eye 2. In the example, a first centroid 50 is shown, characterizing distance values ​​z that lie, for example, on an eyelid or an eyelash of eye 2; a second centroid 52 is shown, characterizing distance values ​​z that lie on the cornea 8 of eye 2; and a third centroid 54 is shown, characterizing distance values ​​z that lie on the sclera 8 of eye 2. These centroids can be referred to as clusters 50, 52, and 54. In particular, cluster 52 is relevant for illuminated points 20c, 22c located on the cornea 8, and cluster 54 is relevant for illuminated points 20c, 22c located on the sclera 6.Clusters 50, 52, 54 can, for example, be determined from the progressions of the distance values ​​z using a clustering algorithm.

[0046] Figure 4 shows a schematic representation of eye 2 from the perspective of event camera 200. It illustrates that the illuminated points 20c and 22c on eye 2 have different shapes depending on whether they lie on the cornea 8 or the sclera 6 of eye 2. Due to differing properties between the cornea 8 and the sclera 6, different volume scattering cones result from the illuminated points 20c and 22c.

[0047] For example, illuminated points on the cornea 8, labeled 22c in the example, exhibit a smaller volume scatter cone than illuminated points on the sclera 6, labeled 20c in the example. This difference in volume scatter cones results in the event camera 300 capturing different event clusters at the respective receiving positions 20e, 22e of the illuminated points 20c, 22c. Consequently, a different number of pixels on the sensor chip of the event camera 200 are illuminated, and thus a different number of events are generated depending on the shape of the receiving positions 20e, 22e of the illuminated points 20c, 22c. Therefore, the illuminated and captured points 20c, 22c can be distinguished by the number of corresponding events occurring in the event camera 200.

[0048] The evaluation unit 300 may be configured to classify point 20c, 22c on the event camera 200 into at least two clusters 52, 54, depending on the determined distance value z or the shape of the illuminated point 20c, 22c. These clusters comprise one cluster 52 for points 20c, 22c located on the cornea 8 of the eyeball 4 and one cluster 54 for points 20c, 22c located on the sclera 6 of the eyeball 4. A classification algorithm may be used for this purpose.

[0049] Figure 5 shows an approximation of a spatial model 30 of the eye 2. In this example, the spatial model 30 is composed of an approximation 32 of the cornea 8 and an approximation 34 of the sclera 6.

[0050] It may be provided that the evaluation device 300 is configured to determine the approximation 32 of the cornea 8 of the eyeball 4 and the approximation 34 of the sclera 6 of the eyeball 4 depending on the classified points 20c, 22c, in particular by means of a sphere for the cornea 8 and a sphere for the sclera 6; to determine a spatial position of a center point 36 of the approximation 32 of the cornea 8 and a spatial position of a center point 38 of the approximation 34 of the sclera 6; and to determine a spatial gaze vector 40 of the eye 2 depending on the spatial positions of the centers 36, 38.

[0051] The approximation 32 of cornea 8 and the approximation of sclera 6 are determined, for example, from at least three points 20c, 22c classified as lying on cornea 8 and at least three points 20c, 22c classified as lying on sclera 6. The approximation 32 of cornea 8 and the approximation of sclera 6, as well as the spatial positions of the centers 36, 38 and the gaze vector 40, are continuously updated. By using more or less illuminated points 20c, 22c, it is possible to dynamically switch between modes with high accuracy, low computational effort, high system sampling rate, and high update rate.

[0052] It may be provided that, depending on a position of the eye 2, for example a pupil 10 of the eye 2, at least one beam angle a is controlled in such a way that a sufficient number of illuminated points 20c, 22c on the cornea 8 or the sclera 6 are detected by the event camera 200 and the corresponding receiving positions 20e, 22e are determined.

[0053] It is conceivable that the device 600 is designed to control at least one beam angle a in such a way that a spatial density of the illuminated points 20c, 22c on the eye 2 and therefore also a spatial density of the determined receiving positions 20e, 22e is adapted depending on the position of the eye 2, for example the pupil 10.

[0054] For example, the spatial density of the illuminated points 20c, 22c can be increased by the last detected position of the pupil 10. This can be achieved, for example, by increasing the sampling rate or sampling speed of the at least one beam angle a and / or decreasing the increment of the sampling rate of the at least one beam angle a and / or adjusting a limit of the at least one deflection angle a. Alternatively or additionally, the modulation frequency of the laser beam 20a, 22a can be increased or decreased to influence the number of events occurring through the detected illuminated points 20c, 22c in the event camera 200.

[0055] It can be provided that the device 600 is designed to control at least one beam angle a in such a way that a temporal density of the illuminated points 20c, 22c on the eye 2 and thus a temporal density of the determined receiving positions 20e, 22e is adapted depending on a dynamic of the eye 2, for example a change in the gaze vector 40.

[0056] For example, with a high dynamic range of eye 2, the temporal density of the illuminated points 20c, 22c is increased. This can be achieved, for example, by increasing the sampling rate or sampling speed of at least one beam angle a and / or decreasing the increment of the sampling rate of at least one beam angle a. Alternatively or additionally, the modulation frequency of the laser beam 20a, 22a can be increased or decreased to influence the number of events occurring at the illuminated points 20c, 22c detected by the event camera 200. Conversely, with a low dynamic range of eye 2, the temporal density of the illuminated points 20c, 22c can be decreased.For example, the sampling rate or sampling speed of at least one beam angle a can be reduced and / or the increment of the sampling rate increased and / or a modulation frequency of the laser beam 20a, 22a reduced in order to reduce the number of events occurring in the event camera 200.

[0057] Figure 6 shows an embodiment of the device 600, which in this example is arranged on a pair of data glasses 400. The device 600 may include a first diffractive deflection device 406 adapted to a wavelength of the laser beam 20a, 22a, in particular a holographic-optical element 406, which is configured to deflect the laser beam 20a, 22a emitted by the illumination device 100 onto the eye 2. The first deflection device 406 is in particular configured as a plane-wave deflector. The deflection device 406 deflects the laser beam 20a, 22c, thereby illuminating the eye 2 with a deflected beam 20b, 22b of the laser beam 20a, 22a.

[0058] It can be provided that the event camera 200 includes a laser line filter 204 adapted to the wavelength of the laser beam 20a, 22a. This ensures that only the illuminated points 20c, 22c are captured by the event camera and that no events caused by stray light are detected by the event camera 200.

[0059] Figure 7 shows a further embodiment of the device 600, which in this example is arranged on the data glasses 400. The device 600 may include a second diffractive deflection device 406b adapted to the wavelength of the laser beam 20a, 22a, in particular a holographic-optical element 406, 406b, which is configured to deflect the beam path 20d, 22d of the illuminated point 20c, 22c onto the event camera 200. The first deflection device 406a and the second deflection device 406b may be integrated into a single deflection device, wherein the deflection device, in particular a holographic-optical element, is divided in its optical function.

[0060] It may be provided that the data glasses 400 comprise the device 600 according to the above descriptions, wherein in particular the lighting device 100 and / or the event camera 200 and / or the evaluation device 300 is arranged in a frame and / or in a temple 402 of the data glasses 400.

[0061] It may be provided that the first deflection device 406a and / or the second deflection device 406b is arranged in a spectacle lens 404 of the data glasses 400.

[0062] Figure 7 also shows, by way of example, a virtual image 100' of the lighting device 100 and a virtual image 200' of the event camera 200. The virtual images 100' and 200' represent the optically effective arrangement and the corresponding base distance B. Thus, it appears as if the lighting device 100 and the event camera 200 are observed or illuminated from one side of the eye 2, although the lighting device 100 and the event camera 200 are not actually arranged in this way.

[0063] Figure 8 shows a method 500, in particular for operating the data glasses 400. The method 500 is generally configured to operate the device 600 according to the above descriptions. The method 500 comprises generating 502 the laser beam 20a, 22a. The method further comprises scanning 504 of the eye 2 with the laser beam 20a, 22a generated by the illumination device 100, for example an infrared laser beam, in particular a modulated infrared laser beam, in at least one dimension, wherein, depending on the at least one beam angle a, the point 20c, 22c on the surface of the eye 2 is illuminated with the laser beam 20a, 22a, in particular in two dimensions, wherein, depending on the first beam angle a and the second beam angle β, the point 20c, 22c on the surface of the eye 2 is illuminated with the laser beam 20a, 22a; and capturing 506 the illuminated point 20c, 22c on the eye 2 by means of the event camera 200.a determination 508 of the receiving position 20e, 22e of the detected point 20c, 22c on the event camera 200; and a determination 510 of the distance value z of the point 20c, 22c, which characterizes a distance z between the surface of the eye 2 and the optically effective arrangement, comprising the lighting device 100 and the event camera 200, depending on the at least one beam angle a, the receiving position 20e, 22e and a geometry of the optically effective arrangement, in particular by means of triangulation depending on a base distance B specified by the geometry between the lighting device 100 and the event camera 200.;

[0064] It may be provided that the method 500 comprises an approximation 512 of the spatial model 30 of the eyeball 4 of the eye 2 depending on a plurality of determined distance values ​​z and at least one beam angle a of corresponding illuminated points 20c, 22c.

[0065] It may be provided that the method 500, as shown in Figure 9, comprises classifying 514 of point 20c, 22c into at least two clusters 52, 54 depending on the determined distance value z or the shape of point 20c, 22c captured by the event camera 200, wherein the at least two clusters 52, 54 comprise cluster 52 for points 20c, 22c that lie on the cornea 8 of the eyeball 4 and cluster 54 for points that lie on the sclera 6 of the eyeball 4.

[0066] It may be provided that the procedure 500 comprises the following steps: a determination 516 of the approximation 32 of the cornea 8 of the eyeball 4 and the approximation 34 of the sclera 6 of the eyeball 4 depending on the classified points 20c, 22c, in particular by a sphere for the cornea 8 and a sphere for the sclera 6; a determination 518 of the spatial position of the center point 36 of the approximation 32 of the cornea 8 and the spatial position of the center point 38 of the approximation 34 of the sclera 6; and a determination 520 of the spatial viewing vector 40 of the eye 2 depending on the spatial positions of the centers 36, 38. It may be provided that the method 500 comprises a deflection 522 of the laser beam 20a, 22a emitted by the illumination device 100 onto the eye 2 by means of the first diffractive deflection device 406a adapted to the wavelength of the laser beam 20a, 22a, in particular by means of a holographic-optical element 406a.

[0067] Furthermore, it is conceivable that the method 500 includes a deflection 524 of the beam path 20d, 22d of the illuminated point 20c, 22c onto the event camera 200 by means of the second diffractive deflection device 406b adapted to the wavelength of the laser beam, for example by means of a holographic optical element 406b.

Claims

Claims 1. Method (500), in particular for operating data glasses (400), comprising the following steps: scanning (504) an eye (2) with a laser beam (20a, 22a) generated by means of a lighting device (100), for example an infrared laser beam, in particular a modulated infrared laser beam, in at least one dimension, wherein, depending on at least one beam angle (a), a point (20c, 22c) on a surface of the eye (2) is illuminated with the laser beam (20a, 22a), in particular in two dimensions, wherein, depending on a first beam angle (a) and a second beam angle (β), a point (20c, 22c) on a surface of the eye (2) is illuminated with the laser beam (20a, 22a); capturing (506) the illuminated point (20c, 22c) on the eye (2) by means of an event camera (200); a determination (508) of a receiving position (20e, 22e) of the detected point (20c, 22c) on the event camera (200);a determination (510) of a distance value (z) of the illuminated point (20c, 22c) which characterizes a distance (z) between the surface of the eye (2) and an optically effective arrangement comprising the lighting device (100) and the event camera (200), depending on the at least one beam angle (a), the receiving position (20e, 22e) and a geometry of the optically effective arrangement, in particular by means of triangulation depending on a base distance (B) between the lighting device (100) and the event camera (200) specified by the geometry.; 2. The method (500) according to claim 1 comprising: an approximation (512) of a spatial model (30) of an eyeball (4) of the eye (2) depending on a plurality of determined distance values ​​(z) and at least one beam angle (a) from corresponding illuminated points (20c, 22c).

3. The method (500) according to claim 1 or 2 comprising: classifying (514) the illuminated point (20c, 22c) depending on the determined distance value (z) or a shape of the illuminated point (20c, 22c) detected by the event camera (200) into at least two clusters (52, 54), wherein the at least two clusters (52, 54) comprise a cluster (52) for points (20c, 22c) that lie on the cornea (8) of the eyeball (4) and a cluster (54) for points that lie on the sclera (6) of the eyeball (4).

4. The method (500) according to claim 3 comprising: determining (516) an approximation (32) of the cornea (8) of the eyeball (4) and an approximation (34) of the sclera (6) of the eyeball (4) depending on the classified points (20c, 22c), in particular by a sphere for the cornea (8) and a sphere for the sclera (6); determining (518) a spatial position of a center point (36) of the approximation (32) of the cornea (8) and a spatial position of a center point (38) of the approximation (34) of the sclera (6); determining (520) a spatial gaze vector (40) of the eye (2), depending on the spatial positions of the centers (36, 38).

5. The method (500) according to one of the preceding claims comprising: deflecting (522) the laser beam (20a, 22a) emitted by the illumination device (100) onto the eye (2) by means of a first diffractive deflection device (406a) adapted to a wavelength of the laser beam (20a, 22a), in particular by means of a holographic optical element (406a).

6. The method (500) according to one of the preceding claims comprising: deflecting (524) a beam path (20d, 22d) of the illuminated point (20c, 22c) onto the event camera (200) by means of a second diffractive deflection device (406b) adapted to the wavelength of the laser beam (20a, 22a), for example by means of a holographic optical element (406b).

7. Device (600) comprising: a lighting device (100) configured to scan (504) an eye (2) with a laser beam (20a, 22a) generated (502) by the lighting device (100), for example an infrared laser beam, in particular a modulated infrared laser beam, in at least one dimension and, depending on at least one beam angle (a), to illuminate a point (20c, 22c) on a surface of the eye (2) with the laser beam (20a, 22a), in particular to scan in two dimensions and, depending on a first beam angle (a) and a second beam angle (β), to illuminate a point (20c, 22c) on a surface of the eye (2) with the laser beam (20a, 22a); an event camera (200) which is designed to detect the illuminated point (20c, 22c) on the eye (2) (506) and to determine a receiving position (20e, 22e) of the detected point (20c, 22c) (508);an evaluation device (300) configured to determine a distance value (z) of the illuminated point (20c, 22c) that characterizes a distance (z) between the surface of the eye (2) and an optically acting arrangement comprising the lighting device (100) and the event camera (200), depending on the at least one beam angle (a), the receiving position (20e, 22e) and a geometry of the optically acting arrangement, in particular by means of triangulation depending on a base distance (B) between the lighting device (100) and the event camera (200) specified by the geometry (510).

8. The device (600) according to claim 7, wherein the evaluation device (300) is configured to approximate a spatial model (30) of an eyeball (4) of the eye (2) depending on a plurality of determined distance values ​​(z) and at least one beam angle (a) of correspondingly illuminated points (20c, 22c).

9. The device (600) according to claim 7 or 8, wherein the evaluation device (300) is configured to illuminate the point (20c, 22c) depending on the determined distance value (z) or a form of the to classify illuminated points (20c, 22c) on the event camera (200) into at least two clusters (52, 54) (512), wherein the at least two clusters (52, 54) comprise a cluster (52) for points (20c, 22c) that lie on a cornea (8) of the eyeball (4) and a cluster (54) for points (20c, 22c) that lie on the sclera (6) of the eyeball (4).

10. The device (600) according to claim 9, wherein the evaluation device (300) is configured to: determine an approximation (32) of the cornea (8) of the eyeball (4) and an approximation (34) of the sclera (6) of the eyeball (4) depending on the classified points (20c, 22c), in particular by means of a sphere for the cornea (8) and a sphere for the sclera (6) (516); determine a spatial position of a center point (36) of the approximation (32) of the cornea (8) and a spatial position of a center point (38) of the approximation (34) of the sclera (6) (518); determine a spatial gaze vector (40) of the eye (2) depending on the spatial positions of the centers (36, 38) (520).

11. The device (600) according to one of claims 7 to 10 comprising a first diffractive deflection device (406a) adapted to a wavelength of the laser beam (20a, 22a), in particular a holographic optical element (406a) configured to deflect the laser beam (20a, 22a) emitted by the illumination device (100) onto the eye (2) (522).

12. The device (600) according to one of claims 7 to 11 comprising a second diffractive deflection device (406b) adapted to a wavelength of the laser beam (20a, 22a), in particular a holographic optical element (406b) configured to deflect a beam path (20d, 22d) of the illuminated point (20c, 22c) onto the event camera (200) (524).

13. A data glasses (400) comprising the device (600) according to one of claims 7 and 12, wherein in particular the lighting device (100) and / or the event camera (200) and / or the evaluation device (300) in are arranged in a frame and / or in a temple (402) of the data glasses (400).

14. The data glasses (400) according to claim 13 and 11 or 12, wherein the first deflection device (406a) and / or the second deflection device (406b) are arranged in a lens (404) of the data glasses (400).

Images