Recording 3d image data using light sectioning

Abstract

The invention relates to recording 3D image data using light sectioning. A camera (10) for recording 3D image data (20) using light sectioning is presented, the camera (10) comprising: an illumination unit (12) for projecting a light pattern (14) in a focal plane (28); an image sensor (22) having a plurality of light-receiving elements in an image plane; a receiving optics (26) arranged upstream of the image sensor (22) and having a lens plane; and a control and evaluation unit (24) which is designed to generate 3D image data by evaluating the light pattern (14) in the recording of the image sensor (22), the image plane being inclined with respect to the focal plane (28). In this case, the receiving optics (26) have at least one optical super element (30), which compensates for an oblique light incidence on the light receiving element.

Description

[0001] The invention relates to a camera and a method for recording 3D image data using the light sectioning method according to the preambles of claims 1 and 15 .

[0002] In the light sectioning method, a light pattern is projected into the inspection area and the height profile of the object is inferred from the deformation using triangulation methods. Laser triangulation using line light sources is particularly common. The inspection is usually carried out in relative motion so that the corresponding 2D height profiles can be combined into 3D image data. In some cases, horizontal surfaces are also measured, thereby detecting brightness images or textures.

[0003] Figure 8 The diagram shows a known Scham arrangement, in which a laser line can be clearly recorded over the entire measuring range in order to obtain high-quality 3D image data. Here, a camera 100 including a lens 102 is constructed such that an image plane 104, a lens plane 106 and a focus plane or focal plane 108 of the camera intersect one another in a common straight line. However, due to the Scham arrangement and the main beam angle of the lens 102, the light strikes the image sensor of the camera 100 obliquely. The effect of the Scham arrangement is the same for all pixels, while the main beam angle has an individual effect on each pixel, i.e. in the case of the central pixel the main beam angle is still 0° and then increases as one moves towards the edge of the image sensor. As a result, the Scham arrangement reduces the light throughput, since not all light reaches the corresponding pixel due to the oblique light incidence. In addition, the volume of a camera constructed with a Scham arrangement is relatively large.

[0004] Fig. 9 A conventional solution for improving the light sensitivity of an image sensor is illustrated. Fig. 9 Each of the small figures a)-c) in FIG. 1 shows an exemplary pixel 110 and its photosensitive surface 112 and a microlens 114 arranged upstream. Thus, when vertical light is incident, as Fig. 9 As shown in the small figure a), the light is focused onto the photosensitive surface 112. However, when the light is incident at an angle, as shown in Fig. 9 As shown in the small figure b) in FIG. 1 , the light may be laterally displaced, causing the photosensitive surface 112 to be partially or completely missed. To compensate, as Fig. 9 As shown in the small figure c) in FIG. 1 , the microlens 114 can have an offset δx relative to the photosensitive surface 112. To this end, the offset δx must be matched to the angle of incidence. This requires a very expensive special design, which must be done again for each sensor variant. The light that misses the photosensitive surface 112 not only reduces the light sensitivity of the image sensor, but also generates stray light that further deteriorates the image recording.

[0005] Another negative effect of oblique incidence of light is multiple reflections in the cover glass. This does not occur when the light is incident perpendicularly, and there are only unwanted back reflections in the direction of the light source that do not reach the image sensor. Anti-reflection coatings also show angle dependence.

[0006] In the paper "Formulas for the coma and astigmatism of wedge prisms used in converging light" by Howard, James W., Applied optics 24.23 (1985): 4265-4268, various possible applications of wedge prisms are discussed. Among other things, wedge prisms can be used to tilt the image plane or to correct the tilt of the image plane. However, this effect is always accompanied by aberrations. Wedge prisms can be free of coma or free of astigmatism, but never both. Therefore, using them for laser triangulation (which is not mentioned in the paper) will bring additional measurement errors.

[0007] The paper "An optic to replace space and its application towards ultra-thin imaging systems" by Reshef, Orad et al., published in Nature communications 12.1 (2021): 1-8, deals with so-called metal lenses and space plates that have nothing to do with laser triangulation. Metal lenses are extremely thin optical elements with a lens effect, which have special nanostructures to influence the beam path. Space plates use similar technology to target the area between lenses, since several metal lenses initially have to be kept at a certain distance from each other like conventional lenses. Space plates are intended to reduce this distance so that the structural depth of the optical device can be further reduced. The special method for producing such nanostructures is nanoimprinting lithography.

[0008] DE 10 2021 119 423 A1 discloses a triangulation sensor which uses an optical metaelement in its receiving path in order to compensate for various adverse triangulation influences. Such a triangulation sensor measures only scalar or one-dimensional data, which should not be confused with a general-purpose camera which records 3D image data using light sectioning or laser triangulation. In DE 10 2021 119 423 A1, camera-specific issues such as the Sham arrangement and the optimization of the two axes of the image sensor do not arise at all. In DE 10 2021 122 418 A1, the displacement of the receiving light spot at close range is particularly limited by the optical metaelement.

[0009] In US2019 / 0170314 A1, a LARP (Laser Activated Remote Phosphor) device is introduced. In various embodiments, wedge prisms, metal lenses and Sham arrangements are mentioned, but they are not linked more closely to each other. The document does not mention laser triangulation.

[0010] It is therefore an object of the present invention to improve the detection of 3D image data using light sectioning methods.

[0011] This object is achieved by a camera and a method for recording 3D image data using the light sectioning method according to claims 1 and 15. The light sectioning method generally refers to the detection of 3D image data based on the deformation of a projected light pattern passing through the contour of an object by means of triangulation, in particular laser triangulation, in which the light is projected as a light pattern. A light source, in particular a laser, projects a light pattern or light in a focal plane. An image sensor with a plurality of light receiving elements or pixels, which are generally arranged in a matrix, records the light pattern on the object it impinges on. A receiving optical device with a lens plane is arranged upstream of the image sensor. A control and evaluation unit evaluates the contour of the recorded light pattern to determine the 3D image data. The image plane is inclined relative to the focal plane.

[0012] The basic idea of ​​the invention is to arrange at least one optical metaelement in the receiving optical device. This allows compensation for the oblique light incidence on the light receiving element. As discussed in the introduction, the oblique light incidence is caused in particular by the inclination between the image plane and the focal plane and / or the corresponding main beam angle. Depending on the embodiment, the metaelement acts on the reflected light beam in a different way and replaces and / or supplements the receiving optical device. For this purpose, the metaelement has a metasurface and / or a metamaterial, i.e. a nanostructure that specifically forms a specific wavefront of the reflected light beam. In the case of a metasurface, such a nanostructure is arranged at the surface, and in the case of a metamaterial, the corresponding properties are achieved by nanostructuring of a layered system or a solid body.

[0013] An advantage of the invention is that smaller angles of incidence on the image sensor can be achieved. This increases the light sensitivity and, depending on the embodiment, also reduces the disturbing side effects of the Sham arrangement, or even achieves the advantages of the Sham arrangement without an actual Sham arrangement, which in turn enables a more compact structural form and simplifies the manufacturing. In some embodiments, the height resolution can be linearized. The optical meta-element is easier to form variants, because other structural forms or other focal planes can be achieved by simply using different meta-elements, or the meta-element can even be matched to other structural forms or fulfill its function in other structural forms. The optical meta-element can fulfill the tasks of the receiving optics with smaller lens errors, or can compensate for the lens errors of the lenses still used in the receiving optics. Due to the optical meta-element, the multiple reflections in the glass cover mentioned in the introduction can be avoided.

[0014] The meta-element preferably produces a prismatic effect. Thereby, the angle of incidence of the incident received light before it falls on the image sensor is changed. Thus, oblique light incidence on the image sensor is reduced to vertical light incidence or at least the oblique angle of incidence in the vertical light incidence direction is reduced.

[0015] Preferably, the meta-element has a different optical effect on each light receiving element. It is conceivable that each light receiving element in the meta-element is compensated individually, but this is not possible using conventional means. It is conceivable that in a meta-element, groups of light receiving elements (e.g., rows or columns) are compensated in the same manner within the corresponding groups.

[0016] Preferably, the receiving optical device has a microlens array arranged upstream of the image sensor. In this way, the effect of the microlens array for focusing the received light onto the photosensitive area of ​​the image sensor and the effect of the optical metaelement provided according to the invention can be combined with each other.

[0017] Preferably, the microlenses of the microlens array have an offset relative to the light receiving element. This offset is usually used to compensate for oblique light incidence, and the optical meta-element according to the present invention can achieve this. Therefore, a standard microlens array without offset can be used, and this has advantages in terms of flexible application and cost for various camera variants. Nevertheless, embodiments combining offset microlenses and the use of meta-elements are still feasible.

[0018] Preferably, the meta-element ensures a perpendicular light incidence in the corresponding microlens. Thus, even a complete compensation of oblique light incidence is achieved.

[0019] Preferably, the meta-element also has the function of a micro-lens array. In this embodiment, the micro-lens array can be omitted, but still achieve an optical effect similar to focusing onto the corresponding photosensitive areas of the light receiving element. In addition to compensating for oblique light incidence, the meta-element itself ensures proper focus on the photosensitive areas of the image sensor.

[0020] In other conceivable combinations, the meta-element only partially replaces the function of the microlens array, so that the microlens array and the meta-element complement each other. Furthermore, it is conceivable that two or more meta-elements share the respective required optical functions.

[0021] Preferably, the receiving optical system has a receiving lens. In such an embodiment, a conventional receiving lens or a conventional receiving optics is still present.

[0022] Preferably, the image sensor is tilted relative to the receiving lens in the Sham arrangement. Thus, the image plane, the lens plane of the receiving lens and the focal plane intersect in a common straight line. The optical metaelement ensures that even if the image sensor is tilted, the received light still strikes the light receiving element as vertically as possible.

[0023] Preferably, the image sensor and the receiving lens are arranged relative to each other such that the image plane and the lens plane are parallel. As an alternative, the Sham arrangement is avoided from a physical point of view. However, the optical metaelement simulates the advantageous optical effects of the Sham arrangement.

[0024] Preferably, the meta-element is designed for focusing light from the focal plane onto the image sensor. Thus, the optical meta-element preferably assumes the function of a receiving lens alone, or alternatively is combined with a receiving lens or is part of the receiving optics. As already mentioned, there may be a plurality of meta-elements, e.g. a meta-element for the function of a receiving lens and a further meta-element for compensating for oblique light incidence, or a single meta-element for both functions.

[0025] Preferably, the meta-element is an active meta-element. This refers to a meta-element whose optical properties can be adjusted. This means that it can be adapted to a specific focal plane or tilt and, for example, to a specific camera or recording situation. Thus, for example, it is not necessary to create multiple meta-elements for a camera variant or a specific application, or at least to some extent, a camera variant can be completely dispensed with by means of an adjustment by means of an active meta-element.

[0026] Preferably, the receiving optics has a space plate. There is no technical term for this in German yet. A space plate is also a metamaterial, but its main purpose is not to change the wavefront by means of a tilt effect or a lens effect. Instead, the space plate should enable longer optical paths in a smaller physical space so that the optical elements, in particular metal lenses, can be arranged closer together. In particular, it is conceivable to provide a metasurface for the front and / or back side of the space plate in order to combine the effects of the space plate with those of the optical metaelement. In embodiments in which the optical metaelement also assumes the dual function of serving as a receiving lens, the space plate enables a particularly compact design. For more detailed information on space plates, please refer to the paper by Reshef et al. presented in the introduction.

[0027] Preferably, the metaelement is preferably designed for multifocal image recording. As a result, different focal planes at different inclinations can be clearly detected. This is of interest for detecting multiple regions of interest (ROI), in particular in the case of multiple laser lines or when using rows of the image sensor for special purposes, such as certain edge rows as color rows.

[0028] Preferably, the meta-element has a deformable property, i.e., has different focusing properties on the two axes of the image sensor. If conventional optical means are used, additional lenses and corresponding installation space and costs are required for this. If necessary, the meta-element can meet such requirements.

[0029] The method according to the invention can be further developed in a similar manner and simultaneously exhibits similar advantages. Such advantageous features are described exemplarily but not exhaustively in the dependent claims which are dependent on the independent claim. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other features and advantages of the present invention will be described in more detail below based on exemplary embodiments and with reference to the accompanying drawings. In the accompanying drawings:

[0031] Figure 1 An overview of a camera and its detection area for 3D image recording according to the light section method or by means of laser triangulation is shown;

[0032] Figure 2 Schematic diagram showing an embodiment of a camera in a Sham arrangement for compensating for oblique light incidence by means of an optical meta-element;

[0033] Figure 3 Schematic diagram showing an embodiment of a camera without a physical Sham arrangement but having a similar optical effect with the aid of an optical meta-element;

[0034] Figure 4shows a schematic diagram of an embodiment of a camera in which the optical meta-element additionally assumes the function of a receiving lens;

[0035] Figure 5 A schematic diagram showing an embodiment of a camera with an additional space board;

[0036] Figure 6 A schematic diagram showing an embodiment of a camera with multiple projected illumination lines and recording areas;

[0037] Figure 7 A schematic diagram showing a multi-focus implementation of a camera;

[0038] Figure 8 A schematic diagram showing a conventional Sham arrangement; and

[0039] Fig. 9 A schematic diagram showing the use of microlenses in general, and in particular offset microlenses, in front of an image sensor is shown.

[0040] Figure 1 An overview of a camera 10 for 3D image recording according to the light section method or by means of laser triangulation in an exemplary recording situation is shown. The principle of laser triangulation is known and will therefore only be briefly described. An illumination unit 12 generates a light fan 14 in the focal plane, which ultimately projects the light onto an object 16 to be detected. The three-dimensional contour of the object 16 deforms the light. During the recording of the camera 10, the shape of the light is evaluated in order to infer the three-dimensional contour based on knowledge of the geometrical arrangement and properties of the camera 10 and the illumination unit 12. In this case, only a two-dimensional height profile corresponding to the object section under the light is generated per recording. By means of a relative movement (e.g. of a conveyor belt 18), the light is gradually guided over the object 16. In this way, 3D image data 20 are then obtained by continuously combining the two-dimensional height profiles.

[0041] Figure 2A schematic diagram of an embodiment of a camera 10 in a Sham arrangement is shown. For simplicity, only the receiving optics of the camera 10 (yet to be explained), the image sensor 22 (which has light receiving elements or pixels not shown separately) and the control and evaluation unit 24 are shown, in which the triangulation evaluation is performed. The control and evaluation unit 24 can be an internal computing unit, an external computing unit, or a combination of the two. Examples of internal computing units are digital computing modules, such as microprocessors or CPUs (Central Processing Units), FPGAs (Field Programmable Gate Arrays), DSPs (Digital Signal Processors), ASICs (Application-Specific Integrated Circuits), KI processors, NPUs (Neural Processing Units), GPUs (Graphics Processing Units), etc. The external computing unit can be any type of controller or computer, including laptops, smartphones, tablets, as well as local networks, edge devices, or clouds.

[0042] In this embodiment, the camera 10 is set up in a Sham arrangement. A single receiving lens 26 is shown as a representative of a receiving lens. Figure 8 As already explained, the Sham arrangement means that the image plane of the image sensor 22, the lens plane of the receiving lens 26 and the focal plane 28 intersect on a common straight line. It is a necessary but not sufficient condition that the focal plane 28 is tilted relative to the image plane.

[0043] In order to compensate for the oblique light incidence on the image sensor 22, an optical meta-element 30 is provided, which is arranged upstream of the image sensor 22. Additionally, a microlens array 32 may optionally be used, preferably between the optical meta-element 30 and the image sensor 22. The microlenses may be arranged as follows: Fig. 9 As shown in the small figure a) in FIG. 1 , a standard assembly with a central microlens is provided, or the microlens can be as Fig. 9 The latter is no longer necessary due to the presence of the optical meta-element 30, but is still possible, for example by the offset and the optical meta-element 30 sharing the required angular compensation with each other.

[0044] The optical superelement 30 has a metamaterial or a metasurface, the latter preferably produced by nanoimprint lithography. Conventional optical components such as lenses, prisms, wave plates or holograms are based on the propagation of light over a distance much greater than the wavelength of the light sector 14 to form a wavefront. In this way, significant changes in the amplitude, phase or polarization of the light wave gradually accumulate along the light path. On the other hand, the optical superelement 30 has structures that can be understood as micro anisotropic light scatterers or resonators or optical antennas. The size and distance of these structures are in the nanometer range, much smaller than the wavelength of the light sector 14. Thus, according to the Huygens principle, the optical superelement 30 introduces spatial variations in the optical response of the light scatterer through the nanostructure, and the optical wavefront is formed into an arbitrary shape with subwavelength resolution. In this way, optical effects, in particular those of lenses or prisms, can be simulated. The characteristic is a high degree of flexibility, and a desired output wavefront is achieved through an adapted nanostructure, thereby achieving various optical effects. Depending on the wavelength range, materials with suitable transmission properties are used, for example titanium dioxide, silicon nitride or gallium phosphide in the visible spectral range, aluminum nitride in the ultraviolet spectral range, chalcogenide alloys in the mid-wave infrared range and silicon in the long-wave infrared range.

[0045] In the camera 10, it is desirable to compensate the incident angle of the received light on the image sensor 22 by the optical meta-element 30, in particular for each light receiving element individually. This is similar to the effect of a wedge prism, but this effect can be achieved without aberrations in the metamaterial. The pseudo-wedge prism can set its own deflection angle for each individual light receiving element, thereby ensuring that the light is incident perpendicularly on the light receiving element. In this case, the oblique light incidence caused by the Sham arrangement and / or the main beam angle depending on the position on the image sensor can be compensated. By pre-specifying this specific optical effect, the required nanostructure can be calculated and generated. If conventional optical elements are used, it is not possible to perform such compensation with the structure size of a single pixel. It is also possible to simply replace the optical meta-element 30 to adapt to different camera variants or applications. The required optical effect can be realized in a single optical meta-element 30 as shown in the figure, or alternatively distributed on two or more optical meta-elements.

[0046] Figure 3A schematic diagram of an embodiment of a camera 10 without a physical Sham arrangement but with a similar optical effect by means of an optical meta-element 30 is shown. The optical effect of the Sham arrangement is a change in the image distance, i.e. a change in the distance between the main plane on the image side and the light receiving elements of the image sensor 22 throughout the image sensor. This serves to compensate for the influence of a tilted object plane and thus for a changing object distance. A sharp recording at a changing object distance can also be achieved by a changing focus position on the image sensor 22, rather than by means of a physical Sham arrangement. Accordingly, in this embodiment the optical meta-element 30 is designed to generate a focus position for each light receiving element, which corresponds to the physical tilt position of the image sensor 22 in the Sham arrangement. The optical meta-element 30 can change the focus position for each light receiving element individually, but preferably only in the height direction, i.e. in the same direction in which the focal plane 28 is tilted relative to the image plane of the image sensor 22. This can be referred to as a simulated Sham arrangement by means of the optical meta-element 30. In addition, it is conceivable to compensate for the main beam angle for each light receiving element in the optical meta-element 30 according to the optical effect of an offset microlens. In this regard, reference is made to the embodiment according to Figure 2 The functions of simulating a Sham arrangement and compensating for the main beam angle may be distributed over two or more optical meta-elements or implemented in a single optical meta-element 30.

[0047] Figure 4 FIG. 1 is a schematic diagram of another embodiment of the camera 10. Figure 3 The difference is that the optical meta-element 30 here also assumes the function of the receiving lens 26 or the receiving lens, and accordingly, the optical meta-element 30 is arranged at a greater distance from the image sensor, approximately at the position of the replaced receiving lens 26. Therefore, the optical meta-element 30 obtains an additional focusing property as a metal lens, just like the replaced receiving lens 26. This focusing function is similar to Figure 3 , in particular in combination with compensation of the main beam angle. Likewise, the various optical functions can be implemented in a single optical meta-element 30, or distributed over at least two optical meta-elements, where in particular the position of the further optical meta-element is near the image sensor 22. As an additional optical function of the same optical meta-element 30 or of another optical meta-element, the height resolution can be linearized, as described in the documents DE 10 2021 119 423 A1 and DE 10 2021 122 418 A1 cited in the introduction, now transferred from a conventional one-dimensional sensor to the camera 10.

[0048] Figure 5 FIG. 1 is a schematic diagram of another embodiment of the camera 10. Figure 4, the optical meta-element 30 replacing the receiving lens 26 had to be arranged at a certain distance from the image sensor 22. Now a space plate 34 is added in order to achieve a more compact structure. As already briefly explained in the introduction, the space plate 34 is a special optical meta-element that is able to replace the longer light path through the air in a very small space. Therefore, due to the space plate 34, the optical meta-element 30 can be arranged very close to the image sensor 22 again. In this way, the entire receiving optics can be realized with a minimum structural depth as a kind of sandwich structure consisting of the image sensor 22, the optional microlens array 32, the space plate 34 and the optical meta-element 30, in particular in a monolithic structure. In other embodiments, a space plate can also be used, but the same compactness cannot be achieved because the conventional receiving lens 26 is still present.

[0049] Figure 6 A schematic diagram of an embodiment of a camera 10 in an arrangement which can be called an inverted Sham arrangement is shown. This is particularly suitable for the case of multiple recording areas, in the example shown there are two laser lines from two lighting units 12a-12b and two RGB areas 36. The two laser lines are preferably offset from each other in the conveying direction in order to be able to carry out multiple measurements. The focal plane in this case is not the plane of the already unclear light fan-shaped areas 14a-14b, but the base plane of the object, such as the surface of a conveyor belt 18. The arrangement shown is particularly suitable for planar objects, such as when inspecting wood.

[0050] Figure 7 A schematic diagram of a multi-focus implementation of the camera 10 is shown. Figure 3 The optical meta-element 30 supports multiple focus positions, so that multiple regions of interest can be detected using different triangulation parameters or focal planes 28a-28b. Thus, in addition to laser triangulation, for example, line-by-line color recording is also possible. Figure 6 The inverted Sham arrangement can also be used for different object distances or object heights, and not just for flat objects.

[0051] As another variant without its own illustration, it is conceivable to impart to the receiving optics a deformable property by means of the optical meta-element 30, ie different focusing properties in the two axes of the image sensor 22. This is particularly applicable to Figure 4 For example, the deformation properties can compress or stretch an image of the same height in width. If conventional lenses are used, this can only be achieved with additional lenses and the additional installation space required for this at very high costs.

Claims

1. A camera (10) for recording 3D image data (20) using a light sectioning method, the camera comprising: an illumination unit (12) for projecting a light pattern (14) in a focal plane (28); an image sensor (22) having a plurality of light receiving elements in an image plane; a receiving optical system (26) arranged upstream of the image sensor (22) and having a lens plane; and a control and evaluation unit (24) designed to generate the 3D image data (20) by evaluating the light pattern (14) recorded by the image sensor (22), wherein the image plane is inclined relative to the focal plane (28), It is characterized in that The receiving optics (26) has at least one optical metaelement (30) that compensates for oblique light incidence on the light receiving element.

2. The camera (10) according to claim 1, wherein: The superelement (30) produces a prismatic effect.

3. The camera (10) according to claim 1 or 2, wherein: The superelement (30) has different optical effects on each light receiving element.

4. The camera (10) according to any one of the preceding claims, wherein: The receiving optics (26) has a microlens array (32) arranged upstream of the image sensor (22).

5. The camera (10) according to claim 4, wherein: The microlenses of the microlens array (32) are offset relative to the light receiving elements.

6. The camera (10) according to claim 4 or 5, wherein: The metaelement (30) ensures normal light incidence in the corresponding microlenses.

7. The camera (10) according to any one of the preceding claims, wherein: The superelement (30) also has the function of a microlens array.

8. The camera (10) according to any one of the preceding claims, wherein: The receiving optical system has a receiving lens (26).

9. The camera (10) according to claim 8, wherein: The image sensor (22) is tilted relative to the receiving lens (26) in a Schaum arrangement.

10. The camera (10) according to claim 8 or 9, wherein: The image sensor (22) and the receiving lens (26) are arranged relative to each other such that the image plane is parallel to the lens plane.

11. The camera (10) according to any one of the preceding claims, wherein: The metaelement (30) is designed to focus light from the focal plane (28) onto the image sensor (22).

12. The camera (10) according to any one of the preceding claims, wherein: The metaelement (30) is an active metaelement whose optical properties can be adjusted.

13. The camera (10) according to any one of the preceding claims, wherein: The receiving optical system (26) has a spatial plate (34).

14. The camera (10) according to any one of the preceding claims, wherein: The metaelement (30) is designed for multifocal image recording and / or wherein the metaelement (30) has deformation properties.

15. A method for recording 3D image data (20) according to the principle of light sectioning, wherein: A light pattern (14) is projected in a focal plane (28), an image sensor (22) having a plurality of light receiving elements in an image plane records the light pattern (14) via a receiving optical device (26) arranged upstream of the image sensor (22), the receiving optical device (26) having a lens plane, and the recorded light pattern (14) is evaluated to generate the 3D image data (20), wherein the image plane is tilted relative to the focal plane (28), It is characterized in that The receiving optics (26) has at least one optical metaelement (30) that compensates for oblique light incidence on the light receiving element.

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