Method and device for detecting scattered light, in particular for determining a position of a pupil of an eye

Abstract

The invention relates to a device and method for detecting scattered light, in particular for determining a position of a pupil (4) of an eye (2), in particular for smartglasses, comprising: scanning a deflection device (104) using a laser beam (106) emitted in a variable emission direction (108), in particular an infrared laser beam, of a laser beam source (102) in at least one dimension, in particular in two dimensions; deflecting the laser beam (106) by means of the deflection device (104), wherein the laser beam (106) is deflected depending on the emission direction (108), and / or depending on at least one wavelength of the laser beam (106), in such a way that the eye (2) is illuminated from a virtual first point (110) or a virtual second point (112), wherein the virtual first point (110) has a first focal length (f1) and the virtual second point (112) has a second focal length (f2), wherein the first focal length (f1) and the second focal length (f2) are different relative to the eye (2); detecting light (120) scattered by the eye (2) from the deflected laser beam (106) by means of a detection device (118), in particular a photodiode.

Description

[0001] Description

[0002] title

[0003] Method and device for detecting scattered light, in particular for determining the position of a pupil of an eye

[0004] State of the art

[0005] The present invention relates to a method and a device for detecting scattered light, in particular for determining the position of a pupil of an eye, especially for data glasses.

[0006] In smart glasses, determining the pupil position of a user's eye typically involves the use of multiple camera sensors. These sensors capture images of the pupil, from which the pupil position is then determined using various algorithms. Consequently, each individual camera sensor requires a mounting location, power and signal connections, and calibration, for example, of focal lengths.

[0007] Therefore, it is desirable to enable an energy-efficient, robust and space-saving determination of the position of a pupil in an eye.

[0008] Disclosure of the invention

[0009] This is achieved by a method, a device and data glasses according to one of the independent claims.

[0010] The method for detecting scattered light, in particular for determining the position of a pupil of an eye, especially for smart glasses, comprises: scanning a deflecting device with a laser beam emitted in a variable direction, in particular an infrared laser beam, from a laser beam source in at least one dimension, in particular in two dimensions; deflecting the laser beam by means of a deflecting device, wherein the laser beam is deflected depending on the direction of emission and / or depending on at least one wavelength of the laser beam such that the eye is illuminated from a virtual first point or a virtual second point, wherein the virtual first point has a first focal length and the virtual second point has a second focal length.wherein the first focal length and the second focal length are different relative to the eye; detection of scattered light from the eye of the deflected laser beam by means of a detection device, in particular a photodiode. The deflection device deflects the laser beam in such a way that it appears as if a point on the eye is illuminated by the laser beam from the first virtual point or the second virtual point, even though the laser beam source is not located at the first and second virtual points. This allows, for example, images of the eye to be created using a single laser beam source and a single detection device, which optically appear as if they were captured from different spatial positions. An interaction between the laser beam source, the deflection device,The system, particularly the virtual first point and the virtual second point, as well as the detection device, can be described, for example, as a virtual stereo camera system. The deflection device thus enables space-saving, energy-efficient, and robust determination of the pupil's position.

[0011] It may be provided that a first section is included by the deflection device in which the laser beam is deflected in such a way that the eye is illuminated by the laser beam from the virtual first point, and a second section is included by the deflection device in which the laser beam is deflected in such a way that the eye is illuminated by the laser beam from the virtual second point.

[0012] It may be provided that the deflection device includes a first optical function by means of which the laser beam is deflected for a first wavelength of the laser beam in such a way that the eye is illuminated from the virtual first point with the laser beam, and the deflection device includes a second optical function by means of which the laser beam is deflected for a second wavelength of the laser beam in such a way that the eye is illuminated from the virtual second point with the laser beam.

[0013] In one example, the method comprises: generating a first image in a first image plane of the eye illuminated from the virtual first point, depending on the direction of emission and the detected scattered light, and a second image in a second image plane of the eye illuminated from the virtual second point, depending on the direction of emission and the detected scattered light; detecting coordinates of at least one property of the pupil, in particular a contour of the pupil and / or a center of the pupil, in the first image plane and coordinates of the at least one property of the pupil in the second image plane using the first image and the second image; transforming the detected coordinates of the at least one property of the pupil from the second image plane and the first image plane into a coordinate system, for example, the first image plane;Determining the position of the pupil, particularly its spatial position, depends on the difference between the transformed coordinates of at least one pupil property from the first image plane and the transformed coordinates of at least one pupil property from the second image plane within the coordinate system, and also depends on the difference between the first and second focal lengths. This allows for efficient determination of the pupil's position. Using the pupil's center as a property increases the accuracy and robustness of determining the pupil's position, as the center can be reliably determined even with blurred or noisy images. Furthermore, the pupil's position can be determined without analyzing a temporal sequence of images, thus reducing or eliminating latency.

[0014] It is possible for the deflection device to be formed by a holographic-optical element, with the first and second sections, or the first and second optical functions, being encompassed by the holographic-optical element. Holographic-optical elements are already available in some smart glasses and serve, among other things, for displaying content to a user. Furthermore, the first and second sections and / or the first and second optical functions can be implemented cost-effectively within the holographic-optical element. By implementing the first and second sections in at least one holographic-optical element, a geometric relationship between the virtual first point and the virtual second point is fixed, and the probability of any variance in this relationship is reduced to a minimum.This makes determining the position of the pupil more robust.

[0015] The deflection device can be formed by at least one segmented lens, wherein the first and second sections and / or the first and second optical functions are encompassed by the at least one segmented lens. The segmented lens can be designed as part of a projection device of the smart glasses or arranged in an optical projection path. This reduces the space required. By implementing the first and second sections and / or the first and second optical functions in the at least one segmented lens, a geometric relationship between the virtual first point and the virtual second point is fixed, and the probability of any variance in this relationship is reduced to a minimum. Therefore, determining the pupil position is more robust.

[0016] The device for detecting scattered light, in particular for determining the position of a pupil of an eye, especially for data glasses, comprises: a laser beam source configured to scan a deflecting device with a laser beam emitted in a variable direction, in particular an infrared laser beam, in at least one dimension, in particular in two dimensions, which is configured to deflect the eye depending on the direction of emission and / or depending on at least one wavelength of the laser beam in order to illuminate the eye from a virtual first point or a virtual second point by means of the laser beam, wherein the virtual first point has a first focal length and the virtual second point has a second focal length, wherein the first focal length and the second focal length are different relative to the eye;A detection device, in particular a photodiode, configured to detect scattered light from the eye of the deflected laser beam. The deflection device may comprise a first section configured to deflect the laser beam to illuminate the eye from a virtual first point using the laser beam, and a second section configured to deflect the laser beam to illuminate the eye from a virtual second point using the laser beam.

[0017] It may be provided that the deflection device includes a first optical function configured to deflect the laser beam for a first wavelength of the laser beam in order to illuminate the eye from the virtual first point with the laser beam, and the deflection device includes a second optical function configured to deflect the laser beam for a second wavelength of the laser beam in order to illuminate the eye from the virtual second point with the laser beam.

[0018] In one example, the device is designed, in particular by means of a computing device, to: generate a first image in a first image plane of the eye illuminated from the virtual first point depending on the direction of emission and the detected scattered light; generate a second image in a second image plane of the eye illuminated from the virtual second point depending on the direction of emission and the detected scattered light;

[0019] to detect coordinates of at least one property of the pupil, in particular a contour of the pupil and / or a center of the pupil in the first image plane and coordinates of the at least one property of the pupil in the second image plane using the first image and the second image; to transform the detected coordinates of the at least one property of the pupil from the second image plane and the first image plane into a coordinate system, for example the first image plane; to determine a position of the pupil, in particular a spatial position, depending on a difference between the transformed coordinates of the at least one property of the pupil from the first image plane and the transformed coordinates of the at least one property of the pupil from the second image plane within the coordinate system and depending on a difference between the first focal length and the second focal length.It may be provided that the deflection device is designed as a holographic-optical element and that the holographic-optical element comprises the first section and the second section and / or the first optical function and the second optical function.

[0020] It may be provided that the deflection device is designed as a segmented lens and that the segmented lens includes the first section and the second section and / or the first optical function and the second optical function.

[0021] The data glasses comprise the device as described above, wherein the deflection device is integrated into a lens of the data glasses or a temple of the data glasses.

[0022] Further embodiments are shown in the drawing and the following description. The drawing shows:

[0023] Figure 1 shows a schematic representation of a device;

[0024] Figure 2 is a schematic representation of a first and second image;

[0025] Figure 3 is a schematic representation of one embodiment of the

[0026] Device;

[0027] Figure 4 shows a schematic representation of one embodiment of the device;

[0028] Figure 5a shows a flowchart of a process;

[0029] Figure 5b shows an excerpt from a flowchart of an embodiment of the method;

[0030] Figure 6a shows a schematic representation of an eye cover;

[0031] Figure 6b is a schematic representation of an embodiment of the

[0032] Eye cover; Figure 6c is a schematic representation of one embodiment of the eye cover.

[0033] Figure 1 shows a schematic representation of a device 100 for detecting scattered light, in particular for determining the position of a pupil 4 of an eye 2, especially for data glasses 200 (Fig. 3). The eye is, for example, the eye 2 of a user of the data glasses 200.

[0034] The device 100 comprises a laser beam source 102 configured to scan a deflection device 104 with a laser beam 106, in particular an infrared laser beam, emitted in a variable emission direction 108, in at least one dimension, and in particular in two dimensions. The variable emission direction 108 can be described, for example, by means of at least one variable deflection angle, and in particular by means of two variable deflection angles. The device 100 also comprises the deflection device 104 configured to deflect the eye 2 depending on the emission direction 108 and / or depending on at least one wavelength of the laser beam 106 such that the eye 2 is illuminated from a virtual first point 110 or a virtual second point 112 by means of the laser beam 106.The virtual first point 110 has a first focal length fi and the virtual second point 112 has a second focal length f2, where the first focal length fi and the second focal length f2 are different relative to eye 2.

[0035] The deflection device 104 may comprise a first section 114 configured to deflect the laser beam 106 to illuminate eye 2 from a virtual first point 110 using the laser beam 106, and a second section 116 configured to deflect the laser beam 106 to illuminate eye 2 from a virtual second point 112 using the laser beam 106. Depending on the emission direction 108, either the first section 114 or the second section 116 is illuminated.

[0036] The deflection device 104 may comprise a first optical function configured to deflect the laser beam 106 for a first wavelength of the laser beam 106 in order to illuminate eye 2 from the virtual first point 110 with the laser beam 106, and the deflection device 104 may comprise a second optical function configured to deflect the laser beam 106 for a second wavelength of the laser beam 106 in order to illuminate eye 2 from the virtual second point 112 with the laser beam 106. For example, the first optical function deflects the laser beam 106 at a different angle for the first wavelength than the second optical function deflects it for the second wavelength of the laser beam 106. A variation in the wavelength of the laser beam 106 can be achieved, for example, by using different sources for the laser beam 106 or by varying a supply signal to the laser beam source 102.

[0037] The first focal length fi and the second focal length f2 can be described as intrinsic parameters of the virtual stereo camera system, which can be determined, for example, by means of calibration.

[0038] The device 100 comprises a detection device 118, in particular a photodiode, configured to detect scattered light 120 from the eye 2 of the deflected laser beam 106. Due to the laser beam 106 being deflected by the deflecting device 104, the detection device 118 perceives a point on the eye 2 illuminated by the laser beam 106, originating from the first virtual point 110 or the second virtual point 112, even though the laser beam source 102 is not positioned at these points 110 and 112. This creates a virtual stereo camera system, requiring, for example, only a single laser beam source 102 and a single detection device 118. The number of virtual cameras in the virtual stereo camera system depends, for example, on the number of sections of the deflecting device 104 or the number of virtual points generated by the deflecting device 104.It may be provided that eye 2 is illuminated by means of the deflecting device 104 from a higher number of virtual points than the one shown.

[0039] The device 100 can be configured to generate a first image 122 in a first image plane h of the eye 2 illuminated from the virtual first point 110 depending on the emission direction 108 and the detected scattered light 120 and to generate a second image 124 in a second image plane I2 of the eye 2 illuminated from the virtual second point 112 depending on the emission direction 108 and the detected scattered light 120.

[0040] By increasing the number of virtual points, for example by increasing the number of sections and / or optical functions of the deflection device 104 and consequently increasing the number of virtual cameras in the virtual stereo camera system, more images of eye 2 can be captured. This increases the robustness of determining the position of pupil 4; moreover, at least three virtual cameras enable the use of a triangulation algorithm to determine the position of pupil 4.

[0041] Figure 2 shows a schematic representation of the first image 122 and the second image 124. Depending on the reflectivity of a surface of the eye 2, light from the laser beam 106 is scattered in the form of scattered light 120. The detection device 118 can be a photodiode configured to detect a brightness value, particularly at a predetermined sampling rate. In this embodiment, the first image 122 and the second image 124 can be generated from the detected brightness values ​​and a corresponding emission direction 108 of the laser beam 106, for example, in the form of a reflectivity map. Alternatively, the detection device can be configured as a pixel sensor that detects the first image 122 and the second image 124.

[0042] The device 100 is configured to detect or determine the coordinates ui, vi of at least one property of the pupil 4, in particular a contour of the pupil 4 and / or a center 6 of the pupil 4 in the first image plane h, and the coordinates U2, V2 of the at least one property of the pupil 4 in the second image plane I2, using the first image 122 and the second image 124. The first image plane h and the second image plane I2 can each be referred to as a coordinate system in which the coordinates ui, Vi, U2, V2 of the at least one property are determined. By means of calibration, extrinsic parameters of the virtual stereo camera system can be determined, which make it possible to transform the first image plane h or the second image plane I2 into each other or into further coordinate systems.The device 100 is designed to transform the detected coordinates ui , Vi, U2, V2 of at least one property of the pupil 4 from the second image plane I2 and the first image plane I2 into a coordinate system, for example the first image plane h.

[0043] Starting from the transformed coordinates, the device 100 is configured to determine a position, in particular a spatial position, of the pupil 4 depending on a difference Au between the transformed coordinates of the at least one property of the pupil 4 from the first image plane h and the transformed coordinates of the at least one property of the pupil 4 from the second image plane I2 within the coordinate system, for example, the first image plane h, and depending on a difference Af between the first focal length fi and the second focal length f2. In other words, the device 100 is configured to determine the position of the pupil 4 depending on the extrinsic and intrinsic parameters of the virtual stereo camera system as well as on the positions of the at least one property of the pupil 4 in the respective image planes h and I2 or coordinate systems.In particular, the distance z between pupil 4 and the virtual first point 110 and the virtual second point 112, respectively, can be calculated using the first image 122 and the second image 124. This makes it possible to determine the spatial position of pupil 4 and thus a gaze vector or gaze direction of eye 2. This gaze vector can be provided to various functions of the smart glasses 200, for example, the selection of an eyebox. The content to be displayed to the user of the smart glasses 200 is presented in the eyebox so that the user can recognize and perceive this content. In the example shown, the first focal length fi is shorter relative to eye 2 than the second focal length f2, which is why the pupil appears larger in the second image 124 than in the first image 122.

[0044] Figure 3 shows a schematic representation of the data glasses 200 with an embodiment of the device 100. The deflection device 104 may be configured as at least one holographic-optical element 128, comprising the first section 114 and the second section 116. The at least one holographic-optical element 128 may be a single holographic-optical element or comprise a plurality of holographic-optical elements. The holographic-optical element 128 may provide further optical functions beyond those of the deflection device 104, such as displaying image content for the user or deflecting the scattered light 120 onto the detection device 118. The deflection device 104 may be integrated into a lens 204 of the data glasses.

[0045] The device 100 can comprise a computing unit 126 configured to generate the first image 122 and the second image 124 and, based on these images, to determine the position of the pupil 4, in particular by means of the procedure described above. The computing unit 126 can, for example, comprise a processor and a memory device.

[0046] In the example shown in Figure 3, the deflection device 104 is scanned by means of a deflection device 102b. The deflection device 102b can, for example, be configured as a micro-electro-mechanical system (MEMS), mirror, lens arrangement, or prism. In this example, the deflection device 102b is configured to emit the laser beam 106 generated by a source 102a onto the deflection device 104 in the variable emission direction 108, wherein the emission direction 108 is varied, in particular in a pattern, to scan the deflection device 104. It can be provided that the emission direction 108 is described or generated by a first and a second deflection angle so that the deflection device 104 can be scanned in two spatial dimensions.

[0047] In the illustrated example, the source 102b of the laser beam source 102 includes the detection device 118 and is configured, for example, as a laser feedback interferometry sensor (LFI sensor). This arrangement can be described as a scanning laser system with an integrated detection device 188, in particular with an integrated photodiode. Using this arrangement of the detection device 118, on-axis detection of the pupil 4 of eye 2 is possible. Due to the high reflectivity of the retina of eye 2, scattered light 120 is reflected into the LFI sensor, resulting in amplitude modulation, which is detected by the integrated detection device 118, for example, in the form of a photodiode. As a result, the pupil 4 of eye 2 appears bright in the first image 122 and the second image 124.At least one property of pupil 4, in particular the center 6 and / or the contour of pupil 4, can then be detected using an image processing algorithm, for example a Canny Edge detector.

[0048] Figure 4 shows a schematic representation of the data glasses 200 with an embodiment of the device 100. The deflecting device 104 may be configured as a segmented lens 130, comprising the first section 114 and the second section 116. The segmented lens 130 may also be configured as a projection optic. In the illustrated example, the lens 204 of the data glasses 200 is configured to deflect the laser beam 106 onto the eye 2, to redirect the scattered light 120 onto the detection device 118, and to display the content to be shown to the user. The lens 204 may, for example, be configured as a holographic optical element or include one.

[0049] In the illustrated example, the detection device 118 is arranged outside the beam path of the laser beam 106. This arrangement can also be described as a scanning laser system with an external detection device 118, in particular with an external photodiode. The detection device 118 is, for example, oriented such that it can directly detect the scattered light 120 from the eye 2, or the scattered light 120 is deflected onto the detection device 118, for example, by means of the spectacle lens 204. The detection device 118 can be configured as a photodiode or a pixel sensor.

[0050] In this arrangement of the detection device 118, off-axis detection of the eye is possible. The pupil 4 of the eye acts as an aperture for the laser beam 106, and little scattered light 120 reaches the detection device 118. The pupil 4 appears dark in the first image 122 and in the second image 124. At least one property of the pupil 4, in particular its center 6 and / or its contour, can then be detected using an image processing algorithm, for example, a Canny Edge detector.

[0051] Figure 5a shows a flowchart of a method 300 for determining the position of a pupil 4 of an eye 2, particularly for data glasses 200, comprising scanning the deflection device 104 with the laser beam 106, in particular an infrared laser beam, emitted in the variable emission direction 108, from the laser beam source 102 in at least one dimension, in particular in two dimensions. Furthermore, the method 300 comprises deflecting the laser beam 106 by means of the deflection device 104, wherein the laser beam 106 is deflected depending on the emission direction 108 and / or depending on at least one wavelength of the laser beam 106 such that the eye 2 is illuminated from the virtual first point 110 or the virtual second point 112.

[0052] The method 300 comprises detecting 306 the scattered light 120 of the eye 2 of the deflected laser beam 106 by means of the detection device 118, in particular a photodiode.

[0053] It can be provided that the first section 114 is encompassed by the deflecting device 104 in which the laser beam 106 is deflected 304 in such a way that the eye 2 is illuminated from the virtual first point 110 with the laser beam 106 and the second section 116 is encompassed by the deflecting device 104 in which the laser beam 106 is deflected 304 in such a way that the eye 2 is illuminated from the virtual second point 112 with the laser beam 106.

[0054] It can be provided that the deflection device 104 includes the first optical function by means of which the laser beam 106 is deflected 304 for the first wavelength such that the eye 2 is illuminated from the virtual first point 110 with the laser beam 106, and that the deflection device 104 includes the second optical function by means of which the laser beam 106 is deflected 304 for the second wavelength such that the eye 2 is illuminated from the virtual second point 112 with the laser beam 106. Figure 5b shows a section of an embodiment of the method 300.The method may include generating 308 the first image 122 in the first image plane h of the eye 2 illuminated from the virtual first point 110 depending on the emission direction 108 and the detected scattered light 120 and the second image 124 in the second image plane I2 of the eye 2 illuminated from the virtual second point 112 depending on the emission direction 108 and the detected scattered light 120.

[0055] It can be provided that the method 300 comprises detecting 310 coordinates ui, vi representing at least one property of the pupil 4, in particular the contour of the pupil 4 and / or the center 6 of the pupil 4 in the first image plane h, and coordinates U2, V2 representing at least one property of the pupil 4 in the second image plane I2, using the first image 122 and the second image 124. In the example shown, the method 300 comprises transforming 312 the detected coordinates ui, Vi, U2, V2 representing at least one property of the pupil 4 from the second image plane I2 and the first image plane h into a coordinate system, for example, the first image plane h.

[0056] The method includes, for example, determining 314 the, in particular spatial, position of the pupil 4 depending on a difference Au between the transformed coordinates of the at least one property of the pupil 4 from the first image plane h and the transformed coordinates of the at least one property of the pupil 4 from the second image plane I2 within the coordinate system, for example the first image plane h and depending on the difference Af of the first focal length h and the second focal length f2.

[0057] Figures 6a, 6b, and 6c schematically depict different coverages of eye 2 by the virtual cameras. These coverages are influenced by a corresponding configuration of the deflection device 104 with respect to the virtual points, for example, the first virtual point 110 and the second virtual point 112. These coverages of the virtual points can also be referred to as the orientations of the virtual cameras. The depicted areas correspond to areas illuminated by light emanating from the virtual points and which can be imaged by images assigned to the respective virtual points. Figure 6b shows an example of a possible coverage of eye 2 with four virtual points: the first virtual point 110, the second virtual point 112, a third virtual point 113, and a fourth virtual point 115.

[0058] Figure 6c shows another example of a possible coverage of eye 2 with four virtual points - the first virtual point 110, the second virtual point 112, the third virtual point 113 and the fourth virtual point 115.

[0059] The shape or pattern of the coverage of the eye with virtual points can be influenced by the design of the deflection device 104. For example, round shapes or different overlaps are conceivable. Relevant for determining the position of the pupil 4 is that the pupil 4 is detected by at least one illumination originating from two virtual points and can therefore be detected in the corresponding images.

Claims

Claims 1. Method (300) for detecting scattered light, in particular for determining the position of a pupil (4) of an eye (2), especially for data glasses (200), comprising: - Scanning (302) of a deflection device (104; 128; 130) with a laser beam (106) emitted in a variable emission direction (108), in particular an infrared laser beam, a laser beam source (102) in at least one dimension, in particular in two dimensions; Deflection (304) of the laser beam (106) by means of the deflection device (104; 128; 130), wherein the laser beam (106) is deflected depending on the emission direction (108) and / or depending on at least one wavelength of the laser beam (106) such that the eye (2) is illuminated from a virtual first point (110) or a virtual second point (112), wherein the virtual first point (110) has a first focal length (fi) and the virtual second point (112) has a second focal length (f2), wherein the first focal length (fi) and the second focal length (f2) are different relative to the eye (2); Detection (306) of scattered light (120) of the eye (2) of the deflected laser beam (106) by means of a detection device (118), in particular a photodiode.

2. The method (300) according to claim 1, wherein a first section (114) is comprised of the deflection device (104; 128; 130) in which the laser beam (106) is deflected (304) such that the eye (2) is illuminated from the virtual first point (110) with the laser beam (106) and a second section (116) is comprised of the deflection device (104) in which the laser beam (106) is deflected (304) such that the eye (2) is illuminated from the virtual second point (112) with the laser beam (106).

3. The method (300) according to claim 1, wherein the deflection device (104; 128; 130) comprises a first optical function by means of which the laser beam (106) for a first wavelength of the laser beam (106) is deflected (304) such that the eye (2) is illuminated from the virtual first point (110) with the laser beam (106) and the deflection device (104; 128; 130) comprises a second optical function by means of which the laser beam (106) is deflected (304) for a second wavelength of the laser beam (106) such that the eye (2) is illuminated from the virtual second point (112) with the laser beam (106).

4. The method (300) according to any of the preceding claims, comprising: generating (308) a first image (122) in a first image plane (h) of the eye (2) illuminated from the virtual first point (110) depending on the emission direction (108) and the detected scattered light, (120) and a second image (124) in a second image plane (I2) of the eye (2) illuminated from the virtual second point (112) depending on the emission direction (108) and the detected scattered light (120); Detecting (310) coordinates (ui, vi) of at least one property of the pupil (4), in particular a contour of the pupil (4) and / or a center (6) of the pupil (4) in the first image plane (h) and of coordinates (U2, V2) of the at least one property of the pupil (4) in the second image plane (I2) using the first image (122) and the second image (124); Transforming (312) the detected coordinates (ui, Vi, U2, V2) of at least one property of the pupil (4) from the second image plane (I2) and the first image plane (h) into a coordinate system, for example the first image plane (h); Determine (314) a, in particular spatial, position of the pupil (4) depending on a difference (Au) between the transformed coordinates of the at least one property of the pupil (4) from the first image plane (h) and the transformed coordinates of the at least one property of the pupil (4) from the second image plane (I2) within the coordinate system and depending on a difference (Af) of the first focal length (h) and the second focal length (f2).

5. The method (300) according to one of the preceding claims, wherein the deflection device (104; 128; 130) is formed by a holographic-optical element (128).

6. The method (300) according to any one of claims 1 to 4, wherein the deflection device (104; 128; 130) is formed by a segment lens (130).

7. Device (100) for detecting scattered light, in particular for determining the position of a pupil (4) of an eye (2), especially for data glasses (200), comprising: a laser beam source (102) configured to scan a deflection device (104; 128; 130) with a laser beam (106), in particular an infrared laser beam, emitted in a variable direction of emission (108), in at least one dimension, in particular in two dimensions (302); the deflection device (104; 128;130), which is configured to deflect the eye (2) depending on the emission direction (108) and / or depending on at least one wavelength of the laser beam (106) in order to illuminate the eye (2) from a virtual first point (110) or a virtual second point (112) by means of the laser beam (106), wherein the virtual first point (110) has a first focal length (fi) and the virtual second point (112) has a second focal length (f2), wherein the first focal length (fi) and the second focal length (f2) are different relative to the eye (2); a detection device (118), in particular a photodiode, which is configured to detect scattered light (120) of the eye (2) of the deflected laser beam (106) (306).; 8. The device (100) according to claim 7, wherein the deflection device (104; 128; 130) comprises a first section (114) configured to deflect (304) the laser beam (106) to illuminate the eye (2) from a virtual first point (110) by means of the laser beam (106), and comprising a second section (116) configured to deflect the laser beam (106) to illuminate the eye (2) from a virtual second point (112) by means of the laser beam (106).

9. The device (100) according to claim 7, wherein the deflection device (104; 128; 130) comprises a first optical function configured to direct the laser beam (106) for a first wavelength of the laser beam (106) to deflect (304) to illuminate the eye (2) from the virtual first point (110) with the laser beam (106) and the deflection device (104; 128; 130) comprises a second optical function configured to deflect (304) the laser beam (106) for a second wavelength of the laser beam (106) to illuminate the eye (2) from the virtual second point (112) with the laser beam (106).

10. The device (100) according to any one of claims 7 to 9, wherein the device (100), in particular a computing unit (126) encompassed by the device (100), is configured to: generate a first image (122) in a first image plane (h) of the eye (2) illuminated from the virtual first point (110) depending on the direction of emission (108) and the detected scattered light (120) (308); generate a second image (124) in a second image plane (I2) of the eye (2) illuminated from the virtual second point (112) depending on the direction of emission (108) and the detected scattered light (120) (308); to detect (310) the coordinates (ui , vi) of at least one property of the pupil (4), in particular a contour of the pupil (4) and / or a center (6) of the pupil (4) in the first image plane (h) and coordinates (U2, V2) of the at least one property of the pupil (4) in the second image plane (I2) using the first image (122) and the second image (124); to transform (312) the detected coordinates (ui , Vi, U2, V2) of the at least one property of the pupil (4) from the second image plane (I2) and the first image plane (h) into a coordinate system, for example the first image plane (h);to determine a, in particular spatial, position of the pupil (4) depending on a difference (Au) between the transformed coordinates of the at least one property of the pupil (4) from the first image plane (h) and the transformed coordinates of the at least one property of the pupil (4) from the second image plane (I2) within the coordinate system and depending on a difference (Af) of the first focal length (fi) and the second focal length (f2) (314).; 11. The device (100) according to any one of claims 7 to 10, wherein the deflection device (104; 128; 130) is configured as a holographic-optical element (128).

12. The device (100) according to any one of claims 7 to 10, wherein the The deflection device (104; 128; 130) is designed as a segment lens (130).

13. Data glasses (200) comprising the device (200) according to one of claims 7 to 12, wherein the deflection device (104; 128; 130) is divided into a The lens (204) of the data glasses (200) or the temple (202) of the data glasses (200) is integrated.

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