Method for calibration and / or adjustment and control unit for a lidar system, lidar system and working device

Abstract

The invention relates to a method for calibrating and / or adjusting a laser radar system (1), wherein, for a measurement-like comparison with regard to a detector unit (20) on which one-dimensional and two-dimensional detection is based, a distribution of secondary light (58) incident from a field of view (50, 50e) and imaged onto the detector unit (20) and a center position and / or a width of the distribution are detected as position data and, in particular, compared with a presumed and / or expected position data with an expected center position and / or an expected distribution.

Description

TECHNICAL FIELD

[0001] The invention relates to a method for calibration and / or adjustment and to a control unit for a laser radar system, to such a laser radar system and to a working device which is configured with a laser radar system and is in particular configured as a vehicle. BACKGROUND

[0002] For the environmental recognition of working devices, in particular of vehicles, so-called laser radar systems (LiDAR: Light Detection and Ranging) are increasingly used which are configured for loading a field of view with light or infrared radiation and detecting and analytically processing the radiation which bounces back from the field of view in order to analyze the field of view and to detect objects contained therein. The quality of the environmental recognition, in particular in relation to the desired effective range of the detection, depends on the quality of the adjustment or orientation of the transmitter unit and the receiver unit relative to one another. Therefore, during the installation and / or operation of the laser radar system, the respective orientation has to be checked and, if necessary, matched. SUMMARY

[0003] In contrast thereto, the method according to the invention has the advantage that the orientation of the transmitter unit and the receiver unit of the laser radar system relative to one another can be checked, set and / or matched with particularly simple means and without personnel outlay. According to the invention, this is achieved in that a method for calibrating and / or adjusting a laser radar system is created in which, for the purpose of a measurement comparison with regard to the underlying detector unit which carries out one- or two-dimensional detection, the distribution of secondary light which is incident from the field of view and imaged onto the detector unit and the center position and / or the width of the distribution are detected as position data and in particular compared with the expected center position and / or the expected distribution, the presumed and / or expected position data.

[0004] The dependent claims show preferred refinements of the invention.

[0005] According to one additional or alternative aspect of the basic concept of the invention, it is proposed in the method for calibrating and / or adjusting a laser radar system that:

[0006] (i) (a) the laser radar system is configured with a transmitter unit and a receiver unit, in particular with a presumed identical angle of view and / or field of view, and / or (b) the area of the underlying detector unit is assigned or has been assigned to each angle of view of the transmitter unit by optical imaging,

[0007] (ii) for the purpose of the measurement comparison, the field of view of the receiver unit is measured in comparison with the field of view of the transmitter unit or respectively the corresponding part of the field of view of the receiver unit is measured in comparison with the corresponding part of the field of view of the transmitter unit,

[0008] (iii) based on the result of the comparison, determining and / or providing a deviation parameter which characterizes a measure of the deviation of the fields of view of the sender unit and of the receiver unit or of the respective portions,

[0009] (iv) based on the value of the deviation parameter, determining and / or providing a correction parameter which characterizes a measure of the required change of the orientation of at least one of the fields of view of the sender unit and of the receiver unit or of the orientation of at least one of the respective portions.

[0010] This means, inter alia, that, in operation, primary light is emitted by the sender unit into the field of view, is reflected there, if necessary, and is detected as secondary light by the receiver unit and is probed there. Here, based on the orientation of the sender unit and of the receiver unit relative to each other, a determined intensity distribution, i.e. with a determined intensity or at a determined detector position, for example in the sense of a macro-pixel composed of single channels and micro-pixels, of the secondary light received is expected on or in the underlying detector assembly for the respective viewing angle, solid angle or observation angle of the sender unit and of the receiver unit. Based on the deviation of the shape and the position of the actually measured distribution from the expected shape and position of the distribution which exists in the case of a desired and in particular optimal alignment of the sender unit receiver unit to each other, a measure of the misalignment can be inferred and further a measure of the necessary readjustment or matching of the orientation of the sender unit and of the receiver unit relative to each other.

[0011] In an advantageous extension of the method according to the application, the orientation of at least one of the fields of view of the sender unit and of the receiver unit or of at least one of the respective portions can be changed in accordance with the value of the correction parameter.

[0012] This can be achieved by different measures:

[0013] It is conceivable, on the one hand, in accordance with a further embodiment of the method according to the application, to change the orientation electrically / electronically, for example in the form of a matching of the analysis processing of the underlying detector unit and / or of the portions thereof, for example in the form of individual detector elements, sensor elements, individual photodiodes or groups thereof, and / or of an assignment to an analysis processing.

[0014] Alternatively or additionally, it is conceivable that the change in the orientation is effected by (ii) changing the assignment of the underlying detector unit and / or parts thereof (for example in the sense of individual detector elements, sensor elements, individual photodiodes or groups thereof) to the field of view and / or parts thereof of the receiver unit. In this context, the parts of the field of view can also be understood as viewing angles, observation angles or corresponding angular ranges or solid angle ranges.

[0015] In addition to these purely electrical, electronic, circuit-technical or "organisational" adjustments, a matching on a mechanical and / or optical level is also conceivable.

[0016] According to a further advantageous extension of the method according to the application, it is therefore conceivable that the change in the orientation is effected mechanically and / or optically by manipulating a mechanical and / or optical adjustment unit.

[0017] Here, a corresponding adjustment unit can be provided and used for matching: (i) the position, orientation and / or alignment of the underlying detector unit and / or parts thereof, and / or (ii) the optical imaging of the secondary light from the field of view onto the underlying detector unit and / or parts thereof.

[0018] According to a further advantageous extension of the method according to the application, it is therefore conceivable that the optical components which lead to the imaging of the secondary light onto the detector unit are set for readjustment or re-adjustment, for example by mechanical movement and orientation of the individual optical components.

[0019] According to a further configuration of the method according to the application, if the distribution of the secondary light on the detector unit and / or the centre position of the distribution is determined by scanning a plurality of macro-pixels of the detector unit (the macro-pixels in particular having one or more single channels with a plurality of micro-pixels in the form of detector elements), a very high precision occurs in the process of the measurement-based comparison,

[0020] The matching of the adjustment or orientation according to the application can be further improved in terms of precision, in that, according to a further embodiment of the method according to the application, a distinction is made between the useful signal from the reflected secondary light and the background noise by using (i) a threshold value for the signal level and / or (ii) a coincidence filter, wherein the latter in particular takes into account the signal shape in space and / or time of the emitted primary light.

[0021] In principle, it is possible that the method according to the application is implemented or applied during the actual operation of the underlying laser radar system and / or in parallel with the actual operation.

[0022] Alternatively or additionally, it is also conceivable, especially in the case of intermediate storage and / or at a later point in time after the measurement process, to implement the method according to the application as a separate process with respect to the normal operation of the underlying laser radar system.

[0023] That is, the method according to the application can be implemented as part of the operating method of the underlying laser radar system, which is however not mandatory.

[0024] Furthermore, the application relates to a control unit for a laser radar system, which is designed to initiate, implement, operate, regulate and / or control the method according to the application in the underlying laser radar system.

[0025] Furthermore, the application also creates a laser radar system of this kind. The laser radar system is designed with a transmitter unit for generating and transmitting primary light into a field of view to illuminate the field of view and a receiver unit for receiving, detecting and analyzing the secondary light from the field of view.

[0026] Furthermore, the laser radar system is designed to be used with and / or controlled or regulated by the method according to the application.

[0027] Additionally or alternatively, the laser radar system has a control unit according to the application, which is designed to control the operation of the transmitter unit and / or the receiver unit of the underlying laser radar system.

[0028] Finally, the application also creates a working device, which is designed with a laser radar system according to the application.

[0029] The working device can be designed in particular as a vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0030] Embodiments of the application are described in detail below with reference to the attached drawings.

[0031] Figure 1 Figures schematically showing embodiments of the laser radar system according to the application, which can be used in connection with the method according to the application,

[0032] Figure 2 A and Figure 2 B illustrate the problem in the intensity distribution of the secondary light at the detector in the case of an adjustment and misadjustment between the transmitter unit and the receiver unit on the basis of schematic views,

[0033] Figure 3the orientation of the intensity distribution of the secondary light at the detector in case of an adjustment and misadjustment between the transmitter unit and the receiver unit is schematically illustrated based on a graph, and

[0034] Figure 4 and Figure 5 the aspect of the distinction between the useful signal and the background noise is illustrated by means of a graph or rather a schematic block diagram. DETAILED DESCRIPTION

[0035] In the following, embodiments of the present application and the technical background are described with reference to Figures 1 to 5 Embodiments of the present application and the technical background are described in detail. Identical and equivalent and identically or equivalently acting elements and components are denoted by the same reference signs. A detailed description of the represented elements and components is not repeated at each occurrence thereof.

[0036] The features and other properties shown can be separated from one another in any form and combined with one another arbitrarily without departing from the core of the present application.

[0037] Figure 1 A diagrammatic illustration of an embodiment of a laser radar system 1 according to the configuration of the present application, which can be used in connection with the method according to the present application, is shown schematically,

[0038] The different aspects of the laser radar system 1 according to the present application shown in Figure 1 have also been included in conventional laser radar systems.

[0039] In current laser radar sensors, the mechanical orientation and adjustment of the transmitter unit 60, in particular the light source unit 65, for example a laser, and the receiving unit 30 relative to one another is carried out during manufacture. The components are fixed here, for example glued or screwed. The mutual orientation cannot usually be detected in operation. Component tolerances and adjustment tolerances are compensated in such a way that, for example, the image size is designed on the receiver side to be larger than the divergence of the light source unit 65 based on which it is based and in particular the laser used there as a light source of the light source unit 65.

[0040] Mechanical tolerances and position changes caused by heat can lead to a significant reduction in the power or performance capability, in particular in terms of the effective range, of the laser radar system 1 over the service life and depending on the temperature.

[0041] To date, this is usually compensated by overfulfilling the specifications based on room temperature, a narrow temperature window or via a tolerance reserve, which leads to additional costs or a reduction in nominal performance.

[0042] According to the present application, these disadvantages can be avoided.

[0043] First of all, the common lidar system 1 according to the present application configured in Figure 1 Fig. 1 shall be illustrated.

[0044] This lidar system has a transmitter unit 60, which can also be understood as a transmitting optics, and a receiver unit 30, which can also be understood as a receiving optics.

[0045] The control unit 40 is advantageously configured in that the transmitter unit 60 and the receiver unit 30 are operatively connected with the control unit via detection lines and control lines 41 or 42.

[0046] The transmitter unit 60 has a light source unit 65 for generating and transmitting primary light 57, a beam shaping optics 66 for beam shaping and a deflection optics 62 for actually transmitting the primary light 57 into a field of view 50 having a scene 53, which can contain for example an object 52.

[0047] In principle, the field of view 50 can be observed in combination with the actual field of view 50s of the transmitter unit 60 and the field of view 50e of the receiver unit 30.

[0048] The receiver unit 30 has a primary optics 34, for example of the type of a lens, and a secondary optics 35, for example having a receiver-side focusing optics.

[0049] The primary optics 34 and the secondary optics 35 of the receiver unit 30 are also used to image the secondary light 58 received from the field of view 50 onto a detector assembly 20 for detection, which has a plurality of sensor elements 22 or detector elements.

[0050] In further operation of the lidar system 1, the transmitter-side wobbling movement 55 causes a scanning of the light field 70 in the field of view 50. That is, if necessary, a line-like light field 71 can be caused to scan over the scene 53 in the field of view 50, for example in horizontal direction, by means of the transmitter-side wobbling movement, for example in the sense of a sampling movement or a scanning movement 73. Alternatively, the exposure of the field of view 50 can be carried out with a plane-like light field 70, for example of the type of a flash, which illuminates the entire field of view 50 at one time, for example in the sense of a flash principle, and without a transmitter-side wobbling movement 55.

[0051] Within the operation of the laser radar system 1 and / or outside of it, in accordance with the application, the distribution of the received secondary light 58 and / or its central position with respect to the arrangement of the detector elements 22 is detected on the receiver side within the detector assembly 20 with individual detector elements or sensor elements 22, for example understood as a whole as a receiver chip. Based on the orientation of the field of view 50s on the transmitter side and the field of view 50e on the receiver side relative to one another or the orientation of their respective corresponding portions relative to one another, and / or by assigning the respective transmitter-side viewing angle or the interval of the transmitter-side viewing angle to the regions of the detector assembly 20 and the plurality of detector elements 22, a distribution with the respective central positions on the plurality of detector elements 22 is expected in accordance with the application and can be compared with the measured distribution and central positions in order to derive therefrom a quantity characterizing the deviation of the actual orientation from the desired orientation, which can then be used to match the orientation of the transmitter unit 60 and the receiver unit 30 relative to one another.

[0052] A core aspect according to one aspect of the application consists in providing, configuring and using a measurement process, if necessary with the aid of a measuring device, for example within the underlying receiving chip, understood as a detector assembly 20 according to the application with a plurality of detector elements or sensor elements 22, for detecting the central position and / or distribution of the light received from the reflection back from the surroundings and as secondary light 58 from the reflection of the laser light of the transmitter unit 60.

[0053] As already mentioned above, this information about the distribution and the central position of the received secondary light is understood as position data and depends to a considerable extent on the mutual orientation of the transmitter 60 and the receiver 30 of the laser radar system 1. In accordance with one embodiment of the application, these position data can be detected in parallel with the normal laser radar measurement and used for evaluation and / or fine adjustment of the position.

[0054] The fine adjustment of the position can be carried out (i) mechanically optically, for example via mirror positions, or (ii) electrically or electronically, for example using further receiving pixels.

[0055] One advantage in the manner according to the application is that the specified effective range can also be achieved during the service life and temperature changes without having to reserve tolerances. Furthermore, in some cases, the initial orientation step that is normally carried out can be completely dispensed with in production.

[0056] Figure 2 In the sub-figures A and 2B, the problem is illustrated exemplarily. Figure 2 A and 2B illustrate the problem exemplarily.

[0057] The secondary light 58 from the field of view 50 falls onto the receiver 30 and in particular onto the detector assembly 20 with the plurality of detector elements or sensor elements 22. The position and width of the intensity distribution can differ from one another within the receiving rows 21, which each correspond to one pixel.

[0058] Here different detector rows 21 of the detector assembly 20 are shown, wherein each row 21 functions as a pixel and is formed by a plurality of detector elements 22. Also shown are initial macro-pixels 23, which are likewise formed by a plurality of associated detector elements 22 arranged in a group and represent the expected center position of the received distribution of secondary light 58 as a central element.

[0059] In practice, however, deviations 80 can occur, for example in the sense of a spatial separation of the actual center position of the distribution of secondary light 58 compared to the expected center position, for example represented by the initial macro-pixel 23, as it is shown in Figure 2 A in the lowermost row of the illustration.

[0060] As a cross-sectional view Figure 2 B shows the distribution of the intensity I of the secondary light 58 as a function of the location in the form of a graph 100, wherein the latter is represented by the arrangement of the individual pixels 22, in particular by the position of the initial macro-pixel 23. The center position 104 of the distribution 103 is clearly located outside the initial macro-pixel 23, and its orientation with respect to the macro-pixel 23 can be used to quantitatively grasp the deviation of the adjustment between the transmitter unit 60 and the receiver unit 30.

[0061] In connection with Figure 2 B, the graph 100, the location x is plotted on the abscissa 101, which is represented by the position of the detector elements 22 or micro-pixels 22, and the intensity I of the secondary light 58 received in the detector assembly 20 is plotted on the ordinate 102.

[0062] In the proposed solution, the light distribution can be generated, for example, by scanning and sampling the signals received via the four channels A to D, which form a macro-pixel 23 with individual detector elements or micro-pixels 22, as it is shown in connection with Figure 3 the graph 200 of A. In this way, the center position, the width and the slope of the distribution 103 of the secondary light 58 can be determined in order to determine and quantitatively grasp the quality of the adjustment and the degree of misadjustment between the transmitter unit 60 and the receiver unit 30.

[0063] In connection with Figure 3The graph 200 plots location x on the horizontal axis 201, which is also represented by the position of the individual detector element 22 (understood as micropixel 22), and plots the intensity I of the secondary light 58 received in the detector assembly 20 on the vertical axis 202. Trajectory 203 shows the intensity distribution for a desired orientation between the transmitter unit 60 and the receiver unit 30, wherein the center position 204 of the intensity distribution 203 is located at the center of the macropixel 23 formed by channels A to D.

[0064] In contrast, distribution 203' shows a center position 204' with a main orientation on channel A, thereby allowing the degree of misalignment between transmitter unit 60 and receiver unit 30 to be inferred from the spacing between center positions 204 and 204'.

[0065] The distinction between the reflected useful signal (i.e., the secondary light 58 reflected from the primary light 57 from the field of view 50) and background noise can be achieved, for example, by considering the light reflected from the primary light 57 from the field of view 50. Figure 4 The threshold method or uniform filter is used to obtain the curve of 300.

[0066] Combining from Figure 4 The graph 300 plots time t on the horizontal axis 301 and the intensity I of the secondary light 58 received in the detector assembly 20 on the vertical axis 302. At a given time t0, the secondary light 58 is detected in different channels A to D in the detector assembly 20. Trajectories 303 and 303' show the temporal variation of the received signal for intensity I in channels A and C. From the comparison of the maximum value at time t0 with the relative intensity descriptions "4" and "10", it can be deduced that the center position of the detected intensity distribution roughly corresponds to the direction of the light received from the detector assembly 20. Figure 3 The process of change of the center position 204' is 203'.

[0067] Here, a threshold 305 is also shown for distinguishing between useful signals and fundamental noise. Only signals above the threshold 305 are allowed as probe signals. Figure 5 Analysis processing logic 400 is shown in the schematic block diagram type. This analysis processing logic is used to determine the light distribution from the dual-channel measurements, as in combination with... Figure 4 As already shown.

[0068] The scanned signal can be analyzed and processed as a digital signal during operation, and combined with it Figure 5 As shown in the analysis and processing logic 400, the data is either stored first and then processed. Since position determination can be performed in parallel with lidar measurements, it can be done across the entire field of view or FoV 50. Therefore, correction can also track the position and parameters of the receiver 30 independently of orientation (horizontally and vertically).

[0069] Combination Figure 5 The block diagram and the analysis and processing logic 400 shown therein should be noted that a comparator 401 is constructed there to work in conjunction with the first counter 402 and the third counter 403.

[0070] The current value of the observed macropixel 23 and a value representing the noise level are fed to the inputs 411 and 412 of comparator 401. The comparison determines whether the detected measurement value is higher than the threshold for noise analysis, and accordingly determines whether the enable signal e appears at the outputs 415 and 416 of comparator 401 and is output to the first and second counters 402 and 403 to take into account the signals of the left and right channels applied to their inputs 413 or 414 for summation, such that the result at the outputs 417 or 418 of the first and second counters 402 or 403 is a result 404 or 405 with the value "10" or "4".

Claims

1. A method for calibrating and / or adjusting a laser radar system (1), wherein For the measurement-comparative comparison with regard to the based-on detector unit (20) on which a one-dimensional or two-dimensional detection is carried out, the distribution of the secondary light (58) incident from the field of view (50, 50e) and imaged onto the detector unit (20) and the center position and / or the width of the distribution are detected as position data and compared with expected position data having an expected center position and / or an expected distribution, wherein: (i) (a) the laser radar system (1) is configured with a transmitter unit (60) and a receiver unit (30), and / or (b) each viewing angle of the transmitter unit (60) is assigned or has been assigned an area of the detector unit (20) on which the based-on optical imaging takes place, (ii) for the measurement-comparative comparison, the field of view (50e) of the receiver unit (30) is compared with the field of view (50s) of the transmitter unit (60), or respectively the respective corresponding parts of their fields of view (50e, 50s) are measurement-comparatively compared with one another, (iii) based on the result of the comparison, a deviation variable is determined, which characterizes a measure of the deviation of the fields of view (50e, 50s) of the transmitter unit (60) and the receiver unit (30), or respectively of the respective parts, and (iv) based on the value of the deviation variable, a correction variable is determined and provided, which characterizes a measure of the required change in the orientation of at least one of the fields of view (50e, 50s) of the transmitter unit (60) and the receiver unit (30), or respectively of the required change in the orientation of at least one of the respective parts, wherein, in correspondence with the value of the correction variable, the orientation of at least one of the fields of view (50e, 50s) of the transmitter unit (60) and the receiver unit (30), or respectively of at least one of the respective parts, is changed, wherein, by using (i) a threshold value for the signal level and / or (ii) a uniform filter, a distinction is made between the useful signal and the background noise from the reflected secondary light (58).

2. The method of claim 1, wherein, The orientation is changed electrically / electronically in such a way that (i) the analysis processing of the based-on detector unit (20) and / or of the part (22) of the detector unit is matched, and / or (ii) the based-on detector unit (20) and / or the part (22) of the detector unit is matched to the assignment of the field of view (50e) of the receiver unit (30) and / or of a part thereof.

3. The method of claim 1 or 2, wherein, The orientation is changed mechanically and / or optically in such a way that a mechanical and / or optical adjustment unit is actuated to match (i) the position, orientation and / or direction of the based-on detector unit (20) and / or of the part (22) of the detector unit, and / or (ii) the optical imaging of the secondary light (58) from the field of view (50) onto the based-on detector unit (20) and / or onto the part (22) of the detector unit. The orientation is changed mechanically and / or optically in such a way that a mechanical and / or optical adjustment unit is actuated to match (i) the position, orientation and / or direction of the based-on detector unit (20) and / or of the part (22) of the detector unit, and / or (ii) the optical imaging of the secondary light (58) from the field of view (50) onto the based-on detector unit (20) and / or onto the part (22) of the detector unit.

4. The method of claim 1 or 2, wherein, The distribution of the secondary light (58) on the detector unit (20) and / or the center position of the distribution is determined by scanning a plurality of macro-pixels of the detector unit (20).

5. The method according to claim 1 or 2, the method - is carried out during normal operation of the underlying laser radar system (1) or in parallel to the normal operation, and / or - is carried out in the case of intermediate storage and / or at a later point in time after the measurement process, as a separate process with respect to the normal operation of the underlying laser radar system (1).

6. The method of claim 1, wherein, The transmitter unit (60) and the receiver unit (30) have the same angle of view and / or field of view (50, 50e, 50s).

7. The method of claim 4, wherein, The plurality of macro-pixels has one or more single channels with a plurality of micro-pixels in the form of detector elements as parts (22) of the detector unit.

8. The method of claim 5, wherein, The method is carried out as part of the operating method of the underlying laser radar system (1).

9. A control unit (40) for a laser radar system (1), the control unit being designed to initiate, carry out, operate, regulate and / or control the method according to any one of claims 1 to 8 in the underlying laser radar system (1).

10. A laser radar system (1), The laser radar system is designed to have - a transmitter unit (60) for generating primary light (57) and for transmitting the primary light into a field of view (50) to illuminate the field of view, and - a receiver unit (30) for receiving, detecting and analytically processing secondary light (58) from the field of view (50), and The laser radar system is designed to be used with and / or controlled or regulated by the method according to any one of claims 1 to 8, and / or the laser radar system has for this purpose a control unit (40) according to claim 9, which is designed to control the operation of the transmitter unit (60) and / or the receiver unit (30).

11. A working device, the working device being designed to have a laser radar system (1) according to claim 10.

12. The working apparatus according to claim 11, wherein The working device is designed as a vehicle. The working device is designed as a vehicle.

Images