Method and apparatus for acquiring image data

Abstract

A method and apparatus for acquiring image data, wherein in the apparatus a transmitting unit comprising a plurality of transmitting elements and a receiving unit comprising more than one receiving pixel are provided, wherein between the transmitting unit and the receiving unit a receiving optics is arranged for superimposing an image of the whole partial scene of the field of view onto an imaging area.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method and a device for acquiring image data. BACKGROUND

[0002] The method and the device for acquiring image data are particularly applied in the field of autonomous driving in a laser radar system. Figure 1 A prior known device of this kind is shown only schematically and comprises a transmitting unit S with a plurality of transmitting elements S1-S4 arranged in at least one row, a receiving unit E with more than one receiving pixel P1-P4 arranged in a row, and at least one receiving optics EO arranged between the transmitting unit and the receiving unit. In this respect, a single transmitting element S1 can emit a light pulse or radiation pulse which is reflected by an object O in a field of view FOV and reaches the receiving pixels P1-P4. Although the emitted radiation is usually in the range of invisible wavelengths, for simplification of representation the terms light and radiation are used as synonyms in the following. For measuring distances, the time of flight of the light pulse can be determined and, due to the different times of flight, a synthetic overall image G of the field of view FOV can be generated from a large number of measurement results. In this so-called time-of-flight (ToF) process, the transmitting elements S1-S4 are usually arranged in a row above one another (e.g. a vertical row), wherein each transmitting element is controlled in a pulse-like manner successively by a control unit C. Due to a transmitting optics SO, the light of each transmitting element forms a light band, e.g. a horizontally oriented light band (see Fig. 2), which illuminates the field of view FOV in a local scene LS1-LS4 in a time- consecutive time window t1-t4. The light is reflected by an object O located in the field of view FOV and back in the direction of the receiving unit E. In the receiving unit E, a plurality of receiving pixels P1-P4 are arranged in a row next to one another, as shown in Fig. 1, so that the light of each local scene can be reflected by the object O and detected as a light band by the receiving pixels. Subsequently, by means of an evaluation device AE, the time of flight of the light between the emission of the pulse and the incidence on the respective receiving pixel is determined, and from the time of flight the distance to the respective reflection position is calculated. Since the other transmitting elements subsequently emit light pulses in turn, the other local scenes LS2-LS4 are illuminated in the time windows t2-t4 in turn. Their light is likewise reflected by the object O and detected by the receiving pixels, so that a two-dimensional image G of the field of view FOV and the object O therein can subsequently be synthesized in a known manner from the calculated distance data. SUMMARY

[0003] It is an object of the present invention to provide a method and a device for acquiring image data by means of which the resolution can be increased at least without changing the structural size.

[0004] According to a first aspect of the present application, the aforementioned object is achieved by a method for acquiring image data. The method comprises the steps of providing a transmitting unit, a receiving unit and at least one receiving optics arranged between the transmitting unit and the receiving unit, wherein the transmitting unit comprises a plurality of transmitting elements arranged in at least one row, and the receiving unit comprises more than one receiving pixel arranged in rows and columns; illuminating a first partial scene of a field of view using a first transmitting element during a first time window; illuminating a further partial scene of the field of view using a further transmitting element during a further time window; wherein, during each time window, light reflected by objects in the respective partial scene is simultaneously projected by the receiving optics onto all receiving pixels; reading out and combining image data received by the receiving pixels in time succession in the respective time windows to form a total image; and not using moving parts in the optical path between the field of view and the receiving unit.

[0005] With the aforementioned method steps, it is achieved that, when illuminating each partial scene with a transmitting element having only one light pulse, all receiving pixels are simultaneously illuminated by the specifically designed receiving optics, so that not only one row or one column of receiving pixels is simultaneously illuminated, but all receiving pixels of the receiving unit are simultaneously illuminated. Since the partial scenes of the field of view are illuminated in time succession, the image data received by the receiving pixels in time succession in the successive time windows can be read out and combined in succession to form a total image. For this purpose, during each individual time window, the light reflected by objects located in the field of view of the respective partial scene is simultaneously projected by the receiving optics onto all receiving pixels of the receiving unit within the time window. Thus, without using moving parts such as rotating mirrors in the optical path between the field of view and the receiving unit, the resolution can be increased, whereby low manufacturing costs and high reliability can be achieved.

[0006] Advantageous embodiments of the present application are described in the specification, the drawings and the dependent claims.

[0007] According to a first advantageous embodiment, in order to increase the resolution, the reflected light of all partial scenes can be superimposed and projected by the receiving optics onto a single imaging area in which all receiving pixels are located. This makes it possible to use a large number of receiving pixels, which are used as a whole for evaluating the reflected light of each partial scene.

[0008] According to a further advantageous embodiment, the at least two partial regions of the local scene which are arranged next to one another are projected by the receiving optics onto the receiving pixels of the receiving unit such that they are arranged above one another and / or spaced apart there. Thereby, there is the possibility to change the resolution of the total image of the field of view in the x-direction and the y-direction by means of the receiving optics. Similarly, the receiving optics can be configured such that the at least two partial regions of the local scene which are arranged next to one another are projected onto the receiving pixels of the receiving unit such that they are arranged next to one another and / or spaced apart there.

[0009] In other words, the receiving optics can perform a desired mapping to achieve different resolutions in certain regions of the synthesized total image. Due to the different designs of the receiving optics, it is possible to adjust the resolution in the case of identical sizes of the emission pixels and the receiving pixels. In accordance with a further advantageous embodiment, the receiving optics can thus be designed, for example, such that the resolution of the two lateral edges of the synthesized total image in the y-direction is enhanced.

[0010] The receiving optics can comprise a plurality of individual lenses, but in particular it can also consist of a single component. The receiving optics can comprise a structure composed of more than one focusing element, which can be designed, for example, as a facet lens or a microlens array, wherein the structure does not necessarily have to be designed as a regular grid structure. In addition to the use of transmissive optics, reflective optics such as a mirror can also be used. Furthermore, the receiving optics can have other optical components, for example a field lens or a focusing element.

[0011] According to a further advantageous embodiment, the adjacent local scenes can be illuminated successively, which facilitates the subsequent synthesis of the total image.

[0012] According to a further advantageous embodiment, the number of illuminated local scenes can correspond to the number of emission elements. In this case, a respective one local scene is illuminated by one emission element during a time window. However, in this respect, when adjacent local scenes are illuminated successively, so-called over-illumination can occur, i.e. light which is radiated into one local scene of the field of view also (unintentionally) illuminates a part of the adjacent local scene, which can lead to inaccurate image data acquisition.

[0013] According to a further advantageous embodiment, in order to prevent such an overexposure, the number of the emission elements can be greater, in particular twice the number of the illuminated local scenes. In this embodiment, a single local scene can first be illuminated by a first emission element and in a subsequent time window by a second emission element, wherein the illumination can take place in such a way that in each case only one partial area of the same local scene is illuminated in each time window. Accordingly, only a predetermined portion of the receiving pixels can be read out in each time window, so that an overexposure of the receiving pixels that are not read out is harmless. Thus, two partial areas of a local scene that are arranged above one another can for example be illuminated successively during two successive time windows, wherein only the upper half of the receiving pixels or only the lower half is read out in each time window. In this way, a first contiguous area of the receiving pixels is read out in a first time window and a further area of the receiving pixels that is contiguous to the first area is read out in a subsequent time window. In this method, indeed more emission elements are required, the number of which is twice that of the preceding embodiment, and twice the number of time windows, but it can effectively prevent the partial areas that are overexposed from influencing the receiving pixels, which would lead to a distortion of the image representation.

[0014] According to a further embodiment, a further way in which the measurement of an undesirably illuminated partial area can be prevented is to mask at least one local scene of the field of view in the receiving optics or to mask at least one local scene of the field of view in the light path between the field of view and the receiving optics. In this way, it is likewise possible to prevent light from the overexposed partial area from influencing the receiving device.

[0015] According to a further advantageous embodiment, such a masking can be implemented in such a way that during each time window only the reflected light of a predetermined partial area of the illuminated local scene is directed onto the receiving pixels. Thus, the receiving optics can for example be masked mechanically or electronically in such a way that always only a predetermined portion of the reflected radiation, such as for example a portion corresponding to a local scene, is not obscured. This can for example be achieved by means of an LCD technology, by a similar rolling window or the like, in which only a predetermined transparent window is provided, which transmits light in the direction of the receiving unit and is moved in synchronism with the control of the emission elements, so that in each case only light from the illuminated local scene influences the receiving pixels.

[0016] According to another aspect of the present application, it relates to a device, in particular for carrying out the method according to at least one of the preceding claims, comprising a transmitting unit, a receiving unit and at least one receiving optics; wherein the transmitting unit comprises a plurality of transmitting elements arranged in at least one row; the receiving unit comprises more than one receiving pixel arranged in rows and columns; the receiving optics is arranged between the transmitting unit and the receiving unit for detecting light reflected by objects in the field of view of the plurality of partial scenes and superimposing them to form a single imaging area. In this respect, the receiving optics can project the imaging area onto all receiving pixels at the same time, so that all receiving pixels of the receiving unit are still illuminated when only one partial scene is illuminated, thereby increasing the resolution. The evaluation device can integrate the image data of all partial scenes received successively by the receiving unit in a known manner to form a total image, wherein the receiving optics can in particular be configured such that the resulting total image has different resolutions in different directions. Thus, the receiving optics can for example be configured such that the two lateral edges of the resulting total image have an enhanced resolution in the vertical direction. BRIEF DESCRIPTION OF DRAWINGS

[0017] The present application will be described below in full detail by way of example with reference to advantageous embodiments and to the accompanying drawings. The drawings comprise:

[0018] Figure 1 is a schematic view of a device according to the prior art;

[0019] Figure 2 is a schematic view of the acquisition of image data using Figure 1 the configuration of the device according to the prior art;

[0020] Figure 3 is a schematic view of a part of the device for acquiring image data between the field of view and the receiving device;

[0021] Figure 4 is a schematic view of the optical path of a further device for acquiring image data between the field of view and the receiving device;

[0022] Figure 5 is a schematic view of the optical path of a further device for acquiring image data between the field of view and the receiving device;

[0023] Figure 6 is a schematic view of the result of the over-illumination of the individual partial scenes;

[0024] Figure 7 is a schematic view of the image data of a first partial area of the partial scene acquired in a first time window;

[0025] Figure 8 is a schematic view of the image data of a second partial area of the partial scene acquired in a second time window;

[0026] Figure 9 is a schematic diagram of a structure for acquiring image data using a covering device. DETAILED DESCRIPTION

[0027] Figure 1 A schematic diagram of a device for acquiring image data according to the prior art is shown, in which in the time-continuous time windows tl-t4, locally adjacent partial scenes LS1-LS4 in a field of view FOV are illuminated by a respective one of the emission elements S1-S4, for example laser diodes, in which at least one object O is located in the field of view. The illumination of the partial scenes takes place, for example, in the form of adjacent horizontal light bands generated by emission optics SO. The individual emission elements S1-S4 are triggered in time in a flash-like manner by a controller C, so that during a time window a respective light band is illuminated on the object O.

[0028] As shown in Fig. 2, the light reflected by the object O in the time window tl is reflected back to a row of receiving pixels P1-P4, the time of flight between the emission of the light pulse and the incidence of the light pulse on the receiving pixels P1-P4 can be determined with an evaluation device AE, in order to be able to calculate the distance between each receiving pixel and the object O. In the next time window t2, another (adjacent) emission element S2 illuminates the adjacent partial scene LS2 and thus the region of the object O adjacent to the partial scene LS1. The light reflected by the object from the partial scene LS2 and the subsequent subsequent partial scenes LS3 and LS4 is then again projected onto the receiving pixels P1-P4 by receiving optics EO, so that the time of flight can be determined for each receiving pixel over the time windows tl-t4. The individual times of flight are then converted into distances by the evaluation device AE, and a two-dimensional composite image G with sixteen pixels arranged in a matrix, as in the illustrated embodiment, can then be created or calculated from the individual distance values in a known manner.

[0029] It should be understood that in the above examples and in the embodiments described below, the number of all rows, all emission elements in a row or column and all receiving pixels is merely exemplary.

[0030] Figure 3A schematic diagram of an apparatus according to the invention for acquiring image data according to the invention is shown. In this respect, the illumination of the respective local scenes LS1–LS4 is performed in the same manner as the structure in FIG1. ​​Therefore, according to the invention, an emitting unit S is also provided comprising a plurality of emitting elements S1–S4 (e.g., laser diodes) arranged in at least one row, wherein the light pulse of each emitting element is converted into a light band by an emitting optics SO, which illuminates the field of view (FOV) of spatially adjacent local scenes LS1–LS4 in a time-continuous time window t1–t4. Due to objects within the field of view (FOV), the light is reflected by objects in each local scene LS1–LS4 and imaged onto an imaging region AB by a receiving optics EO. The imaging region AB is then projected onto a receiving unit E, which has more than one receiving pixel P1–Px arranged in rows and columns. The receiving unit E is configured to... Figure 1 The device is connected to the evaluation device AE in the same manner, which combines the image data received continuously in time by the receiving unit E to form a total image G.

[0031] exist Figure 3 In this diagram, different objects within the field of view (FOV) are displayed in different local scenes LS1–LS4. For simplicity, they are shown as geometric objects only in the form of triangles, squares, rectangles, and two circles. A special function of the receiving optics EO used according to this invention is that it simultaneously projects the light reflected from all objects in all local scenes onto all receiving pixels P1–Px of the receiving unit. Therefore, the receiving optics EO can "see" all local scenes LS1–LS4 of the FOV at all times, and superimpose the reflected light from all local scenes onto a single imaging area AB, which is then projected onto the receiving pixels P1–Px of all receiving units E. The result is that the images of all local scenes are superimposed to form the imaging area AB, thus all geometric objects in each local scene are superimposed in the imaging area AB, such as… Figure 3 As shown in the enlarged view on the right.

[0032] In order to use Figure 3The shown device acquires image data, first by illuminating a first local scene LS1 in the field of view FOV by a first emitting element S1 during a first time window t1 such that light reflected by a triangular object in the local scene LS1 is projected onto the imaging area AB. This light is projected by the receiving optics EO onto all receiving pixels P1-Px of the receiving unit E during the time window t1, the thus generated image data being read out by the evaluation device AE. During a subsequent time window t2 only the adjacent local scene LS2 is subsequently illuminated by a second emitting element S2 and light reflected by a square object in the local scene LS2 is imaged onto the imaging area AB and projected onto all receiving pixels. Thus, the individual local scenes are illuminated in time, especially in a flash-like manner, in succession, wherein the control device C of the emitting elements is configured such that it controls the emitting elements in an alternating and successive manner in a predetermined order. The evaluation device AE can then read out the image data received by the receiving pixels in time succession in the time windows and can combine them to form a total image G.

[0033] The method and device described according to the present application can achieve high precision at low cost, since no moving parts are used in the light path between the field of view FOV and the receiving unit E.

[0034] Figure 4 Another embodiment is shown, in which the receiving optics EO are configured such that light reflected by an object O in a local scene in the time windows t1, t2 and t3 is projected onto three receiving pixels P3, P2 and P1 arranged above one another in a manner corresponding to the partial areas C, B and A, and onto a plurality of receiving pixels (not shown) arranged adjacent to one another; thus, the resolution of the device for acquiring image data can be further improved.

[0035] Figure 5 Another embodiment is shown, in which the emitting optics SO are configured such that the vertical light bands projected by a respective one of the emitting elements onto the object O in the different time windows t1, t2 and t3 are imaged onto, for example, six receiving pixels P1-P6. Each local scene has two partial areas A and B arranged above one another in each time window t1-t3.

[0036] In this embodiment, the receiving unit E has six receiving pixels P1-P6 arranged in three rows and two columns. Among these, the receiving pixels P1, P2 and P3 are located in one column, while the receiving pixels P2, P4 and P6 are located in the other column adjacent thereto.

[0037] In this embodiment, the receiving optics EO is configured such that each partial area A and B of the local scene arranged above one another is projected from the object O onto the receiving pixels, so that the reflected radiation of the partial area A is incident on the receiving pixels PI, P3 and P5, while the partial area B is imaged onto the receiving pixels P2, P4 and P6. The partial areas A and B arranged above one another on the object O are thus imaged on the receiving pixels of the receiving unit such that they are arranged adjacent to one another there and are projected onto, for example, three receiving pixels. The resolution of the overall image in the y direction is thus enhanced compared to the x direction.

[0038] The following is described with reference to Figure 6 The problem of overexposure of individual local scenes is explained.

[0039] As described above, in the method according to the application, the individual local scenes of the field of view are illuminated successively, in particular in a strip-like manner, and the light reflected by the illuminated local scenes is projected onto all receiving pixels by means of the receiving optics. Since the overall field of view is in fact projected onto all receiving pixels at the same time, but only one local scene is illuminated at all times, the receiving unit always records only the light reflected by one local scene in the successive time windows. Thus, for example, in Fig. 6 only the emitting element SI illuminates the local scene LS1, by means of the receiving optics the light of the entire local scene LS1 is projected onto the receiving unit E comprising all pixels PI - Px. However, as shown in Fig. 6, it is not always possible to illuminate each local scene precisely up to the adjacent local scene, which is in fact not illuminated in the current time window. In this respect, during the preparation of the light radiation for the local scene LS1 into the adjacent local scene LS2, the aforementioned overexposure can occur. This, however, leads to the receiving pixels in the top row of the receiving unit E being not only (completely) illuminated in the first local scene LS1, but also (partially) receive light in the adjacent local scene LS2. According to the application, however, since all local scenes are always superimposed by the receiving optics E onto a single imaging area AB, this leads to the receiving pixels in the top row of the receiving unit E receiving reflections not only from the local scene LS1, but also partly from the local scene LS2, which can lead to incorrect results. Figure 6 One solution to this problem can be to illuminate each local scene alternately using more than one emitting element, but in this respect only a part of the receiving pixels is read in each time window. Thus, for example, a first continuous area of receiving pixels can be read out in a first time window, and in a subsequent time window another continuous area adjacent to the first area and illuminating the same local scene is read out. Thus, in

[0040] Figure 7 ​In the arrangement, each local scene is equipped with two emitting elements S1, S1' to S4, S4', wherein the two emitting elements are provided to illuminate different regions TB1 and TB2 of the same local scene LS1. Therefore, emitting element S1, for example, illuminates the upper region TB1 of local scene LS1 in time window t1. Figure 7 The emitting element S1' illuminates the lower region TB2 of the local scene LS1 in the subsequent time window t1' (Figure 8). However, to avoid over-illumination, only the receiving pixels located in the upper half are read out when the emitting element S1 is activated; that is, only the receiving pixels arranged in the top two rows are shown in this embodiment. In contrast, at this time point, the lower two rows of receiving units E remain inactive. Conversely, when the lower region of the local scene LS1 is illuminated by the emitting element S1', the upper two rows of receiving pixels switch to an inactive state. Through this process, for each local scene, actually twice the number of emitting elements are required, and two illumination sequences must be passed. However, the problem of cross-fading is no longer present.

[0041] Figure 9 This paper illustrates another solution to avoid information errors caused by cross-blending. In this solution, a masking device is provided to obscure at least one adjacent local scene within the field of view (FOV). This device is positioned in the region of the receiving optics (EO), integrated into the receiving optics (EO), or positioned in the optical path between the FOV and the receiving optics (EO). Figure 9 As shown, when a local scene LS1 is illuminated by the emitting element S1, the areas of all adjacent local scenes LS2-LS4 are covered or masked, so that the imaging area AB actually receives only reflected radiation from the first local scene LS1. This masking can be achieved, for example, through a mechanical aperture or an electronic aperture, i.e., through a transparent transmission window, which, in different situations, emits reflected radiation from only one desired local scene. Therefore, the receiving optics EO can, for example, integrate a scrolling window, synchronized in time with the controller C of the emitting element by means of an LCD light-shielding device, so that, in different situations, only reflected light is transmitted from the currently illuminated local scene to the imaging area AB.

[0042] Since the controller C controls each transmitting element S1–S4 in a predetermined order, and the evaluation device AE combines the image data received continuously in time by the receiving unit E to form a total image G, a high-resolution two-dimensional image with breadth in the x-direction (image width) and different resolutions in the y-direction (image height) can be generated.

Claims

1. A method of acquiring image data, characterized by, comprising the steps of: a) providing a transmitting unit (S) comprising a plurality of transmitting elements arranged in at least one row, a receiving unit (E) comprising receiving pixels arranged in rows and columns, and at least one receiving optics (EO) arranged between the transmitting unit (S) and the receiving unit (E); b) illuminating a first partial scene of a field of view (FOV) during a first time window (t1) using a first transmitting element; c) illuminating a further partial scene of the field of view (FOV) during a further time window (t2) using a further transmitting element; d) during each time window, simultaneously projecting light reflected by objects in the respective partial scene onto all receiving pixels by means of the receiving optics (EO); e) reading out image data received by the receiving pixels in time succession during the time windows and combining them to form a total image (G); f) no moving parts are used in the optical path between the field of view (FOV) and the receiving unit (E); wherein the reflected light of all partial scenes is superimposed by means of the receiving optics (EO) and projected onto a single imaging area (AB) to increase the resolution.

2. The method of claim 1, wherein, At least two partial areas (A, B) of a partial scene arranged next to each other are projected by means of the receiving optics (EO) onto the receiving pixels of the receiving unit (E) such that they are arranged above each other and / or spaced apart there.

3. The method of claim 1, wherein, At least two partial areas (A, B) of a partial scene arranged above each other are projected by means of the receiving optics (EO) onto the receiving pixels of the receiving unit (E) such that they are arranged next to each other and / or spaced apart there.

4. The method of claim 1, wherein, Adjacent partial areas (A, B) of a partial scene are projected by means of the receiving optics (EO) onto different numbers of receiving pixels.

5. The method of claim 1, wherein, Adjacent partial scenes are illuminated in succession.

6. The method of claim 1, wherein, A facet lens is used as receiving optics (EO).

7. The method of claim 6, wherein, The facet lens is a monolithic facet lens.

8. The method according to any one of claims 1 to 7, characterized in that, The number of illuminated partial scenes corresponds to the number of transmitting elements.

9. The method according to any one of claims 1 to 7, characterized in that, The number of transmitting elements is greater than the number of illuminated partial scenes.

10. The method of claim 9, wherein, The number of transmitting elements is twice the number of illuminated partial scenes.

11. The method of claim 9, wherein, During two consecutive time windows (t1, t1'), different partial areas (TB1, TB2) of a partial scene (LS1) are illuminated in succession by a first transmitting element and a second transmitting element, and only some of the receiving pixels are read out in each time window.

12. The method of claim 11, wherein, A first continuous area of the receiving pixels is read out in a first time window (t1), and a further continuous area of the receiving pixels is read out in a subsequent time window (t1'), the further continuous area being adjacent to the first area.

13. The method according to any one of claims 1 to 7, characterized in that, At least one partial scene of the field of view (FOV) is obscured in the receiving optics (EO) or in the optical path between the field of view (FOV) and the receiving optics (EO).

14. The method according to any one of claims 1 to 7, characterized in that, During each time window, only the reflected light of the illuminated predetermined partial areas (TB1, TB2) of the partial scene is directed onto the receiving pixels.

15. An apparatus for performing the method according to any one of claims 1 to 14, characterized in that An emission unit (S), a receiving unit (E) and at least one receiving optics (EO) are provided; the emission unit (S) comprises a plurality of emission elements arranged in at least one row; the receiving unit (E) comprises receiving pixels arranged in rows and columns; the receiving optics (EO) is arranged between the emission unit (S) and the receiving unit (E) for detecting light reflected by objects (O) in the field of view (FOV) of a plurality of partial scenes and superimposing them to form a single imaging area (AB).

16. The apparatus of claim 15, wherein, The receiving optics projects the imaging area (AB) onto all receiving pixels simultaneously.

17. The apparatus of claim 15, wherein, An evaluation device (AE) is provided for combining image data received by the receiving unit (E) in succession in time to form a total image (G) having an x-direction and a y-direction, wherein the receiving optics (EO) is configured such that the resultant total image (G) has different resolutions in the x-direction and / or the y-direction.

18. The apparatus of claim 17, wherein, The receiving optics (EO) is configured such that both lateral edges of the resultant total image (G) have an enhanced resolution in the y-direction.

19. The apparatus of claim 15, wherein, The receiving optics (EO) is configured such that at least two partial areas (A, B) of a partial scene arranged next to each other are arranged above and / or spaced apart from each other on the receiving pixels of the receiving unit (E); or, At least two partial areas (A, B) of a partial scene arranged above each other are arranged next to each other and / or spaced apart from each other on the receiving pixels of the receiving unit (E).

20. The apparatus of claim 15, wherein, A controller (C) is provided for controlling the emission elements in an alternating and continuous manner in a predetermined sequence.

21. The apparatus of any one of claims 15 to 20, wherein, The receiving optics (EO) comprises a facet lens.

22. The apparatus of claim 21, wherein, The facet lens is a monolithic facet lens.

23. The apparatus of any one of claims 15 to 20, wherein, There are no moving components in the optical path between the field of view (FOV) and the receiving unit (E).

24. The apparatus of claim 15, wherein, A masking device is arranged in the receiving optics (EO) or in the optical path between the field of view (FOV) and the receiving optics (EO) for masking at least one partial scene of the field of view (FOV).

25. The apparatus of claim 15, wherein, A masking device is arranged in the receiving optics (EO) or in the optical path between the field of view (FOV) and the receiving optics (EO) for emitting reflected light from only one partial scene of the field of view (FOV) to the receiving unit (E).

26. The apparatus of claim 24, wherein, The masking device comprises a mechanical aperture stop or an electronic aperture stop.

27. The apparatus of claim 26, wherein, The masking device comprises an LCD aperture stop.

28. The apparatus of any of claims 24-27, wherein, The masking device is synchronized in time with the controller (C) of the emission elements.

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