METHOD FOR OBTAINING ANGLE VALUES OF A ROTARY MOTION AND OPTICAL DETECTION SYSTEM

Abstract

The present disclosure relates to a method for obtaining angular values ​​of a rotational motion of an optical beam guidance device (16), comprising receiving values ​​(VM) that indicate measured angular values ​​of the rotational motion, Obtain first filtered values ​​(FV1) by filtering the received values ​​using a first filter (F1), Obtaining second filtered values ​​(FV2) by filtering the received values ​​using a second filter (F2), Alternating output of a multitude of first filtered values ​​(FV1) and a multitude of second filtered values ​​(FV2). The disclosure further relates to an optical detection system (10), a vehicle (20) comprising the same, and a computer program product.

Description

Technical area

[0001] The present disclosure relates to a method for obtaining angular values ​​of a rotational motion of an optical beam guidance device. The optical beam guidance device may be included in an optical detection system such as a lidar system. The disclosure further relates to the optical detection system, a vehicle, and a computer program product. background

[0002] Modern vehicles such as cars, vans, trucks, motorcycles, etc. may include sensor systems whose data is used for driver information and / or by driver assistance systems.

[0003] Sensor systems are continuously being developed for various functions, such as capturing environmental information at close and long ranges of vehicles, like passenger cars or commercial vehicles. Based on the collected data, a model of the vehicle's surroundings can be created, enabling the system to react to changes in this environment. Sensor systems can also serve as sensors for driver assistance systems, particularly those for autonomous or semi-autonomous vehicle control. For example, they can be used to detect obstacles and / or other road users in front of, behind, or in the vehicle's blind spot. Sensor systems can be based on different sensor principles, such as radar, ultrasound, and optics.

[0004] A key principle of optical sensors for environmental detection, such as in vehicles, is lidar technology (lidar: light detection and distance measurement). A lidar system comprises an optical transmitter and an optical receiver. The transmitter emits an optical signal, which can be continuous or pulsed. Furthermore, the optical signal can be modulated. For example, electromagnetic waves in the form of laser beams in the ultraviolet, visible, or infrared range can be used as optical signals in a lidar system. The light of the optical signal is received by the optical receiver after reflection from an object within the detection range of the lidar system. The optical signal can then be evaluated, for example, using a time-of-flight method, and the spatial position and distance of the object from which the reflection occurred can be determined.Furthermore, it may be possible to determine a relative velocity. Reflection or reflected light are understood here to mean any light that is reflected back, and can also include light that is reflected back through scattering or absorption emission.

[0005] Scanning lidar systems emit optical signals that move in a scan direction. This scan movement can be achieved by guiding the optical signal, transmitted by the optical transmission device, using a beam steering device. The beam steering device can include at least one rotating mirror. The optical signal can be pulsed. The scan movement of the optical detection system depends on the angular position of the rotating mirror at the time of reflection of the optical signal. Therefore, for pulsed optical signals, the timing of emission by the optical transmission device is critical.

[0006] German patent application DE102020132003A1 describes a method for timing an event as a function of the angular position of a rotatable object. A sensor signal relating to the angular position is received by an angle sensor. A series of arrival times corresponding to successive signal features of the sensor signal is determined. A mean arrival time of an actual signal feature and at least one preceding signal feature is calculated, and the arrival time of a subsequent signal feature is estimated as a function of the mean arrival time. The event is then timed as a function of the estimated arrival time. Furthermore, a method for operating an active optical sensor system is described, wherein a rotatable mirror of the active optical sensor system is mechanically coupled to an angle sensor.The angle sensor is designed to generate the sensor signal depending on the angular position of the rotatable mirror. Brief description

[0007] An optical beam guidance system performs a rotational movement. A method for obtaining angular values ​​of the rotational movement includes... • Receiving values ​​that indicate measured angular values ​​of the rotational movement, • Obtain first filtered values ​​by filtering the received values ​​using a first filter, • Obtaining a second filtered value by filtering the received values ​​using a second filter, • Alternating output of a large number of first filtered values ​​and a large number of second filtered values.

[0008] An optical detection system comprises an optical beam guidance device and a control unit. The optical beam guidance device is designed to perform a rotary movement. The control unit is designed to • Receiving values ​​that indicate measured angular values ​​of the rotational movement, • Obtain first filtered values ​​by filtering the received values ​​using a first filter, • Obtaining a second filtered value by filtering the received values ​​using a second filter, • Alternating output of a large number of first filtered values ​​and a large number of second filtered values.

[0009] The optical beam steering device can be configured to perform beam steering of an optical detection system, in particular a lidar system. Beam steering can be used, for example, to perform a scanning motion of an optical signal. The rotational movement of the beam steering device can include a rotational movement of at least one mirror of the optical beam steering device, wherein the mirror provides a reflective surface for an optical signal from the optical detection system to change its direction. The angular position of the mirror directly influences the direction in which the optical signal of the lidar system is deflected.

[0010] For certain embodiments of optical detection systems that operate with a pulsed optical signal, the timing of the transmission of a pulse of the optical signal depends on the angular position of the beam-guiding device, which may include, for example, a rotating mirror. To improve the precision of the optical detection by the optical detection system, the angular position of the beam-guiding device can be precisely measured using the described method or system.

[0011] Filtering the received values ​​allows for a more precise estimation of the actual angle values ​​from the measured angle values, as variations in the measurement can be taken into account. This improves the overall precision of the measurement. Precision is a measure of the accuracy of repeated measurements—how close they are to each other.

[0012] For certain applications, e.g., with many values ​​to be processed or with high timing constraints, filtering using only one filter can lead to problems, e.g., buffer or other storage overflow, variable overflow, stack overflow, or similar issues.

[0013] The described method uses at least a first and a second filter. The output of these at least two filters is used alternately. The output of each filter can therefore be used alternately with the output of the other filter. The period for which the output of each filter is used can, for example, be limited to a duration during which the filter output is "healthy," e.g., without adverse effects due to, for example, overflow.

[0014] The rotational movement of the beam guidance device can be driven by a drive motor, and the angular values ​​of the optical beam guidance device's rotational movement can depend on the rotational movement of the drive motor. In particular, the angular values ​​of the beam guidance device's rotational movement can depend on the angular values ​​of the drive motor. The drive motor may exhibit inaccuracies in its motion, which in turn can affect the rotational movement of the beam guidance device. For example, there may be jitter in the values ​​indicating the measured angular values ​​of the beam guidance device's rotational movement.

[0015] The values ​​indicating the measured angular motion of the beam guidance device can be detected by an angular position sensor, which can be directly or indirectly mechanically coupled to the beam guidance device and is designed to detect the measured angular motion of the beam guidance device. The angular position sensor can be directly coupled to the beam guidance device, or it can be indirectly coupled to it, for example, by coupling it to the drive motor, which also performs a rotary motion, with the rotary motion of the beam guidance device being dependent on the rotary motion of the drive motor. The angular position sensor can, for example, include a rotary encoder connected to a shaft of the drive motor and / or the beam guidance device.

[0016] In certain embodiments, the filtered output values ​​are used to obtain the angular values ​​of the beam guidance device's rotation, with the obtained angular values ​​being relative to the received values. Filtering the received values ​​improves their precision, for example, by reducing the effect of jitter. More precise angular values ​​of the beam guidance device's rotation can be obtained from the filtered values.

[0017] In certain embodiments, the plurality of first filtered values ​​comprises several consecutive first filtered values, and the plurality of second filtered values ​​comprises several consecutive second filtered values. In this embodiment, the switching between first and second filtered values ​​occurs after a plurality of filtered values ​​from each filter has been output. The filtered values ​​from one filter are output for a certain period, e.g., while that filter is in a "healthy state," then the output switches to the other filter. This reduces the switching overhead. The values ​​obtained from a filter are output for a specific period, e.g., as long as their quality is good.

[0018] The received values ​​can be incremental, specifically representing increments of angle values. The received values ​​can also be a sequence of characteristic features in a sensor signal received by the angle position sensor. Such characteristic features can also be called "ticks" and can, for example, correspond to edges in the sensor signal.

[0019] According to one embodiment, the method includes using the filtered output values ​​to estimate a future angle value relative to a future received value, and / or to estimate a further future angle value equal to half that future angle value. Filtering allows for a more precise estimation of a future value that indicates a future angle value, as variations in the measurement can be taken into account. This improves the overall precision of the measurement and the precision of an estimated future angle value. Estimating the intermediate angle values, particularly half angle values, will allow for a finer granularity of future angle values. When used in a scanning lidar system, this can increase the resolution of the scan motion and the associated point cloud.

[0020] In one embodiment, the method further comprises controlling the timing of an optical signal transmission based on the estimated angular values ​​of the rotational movement. In one embodiment of the optical detection system, the control unit is designed to control the timing of an optical signal transmission based on the angular values ​​of the rotational movement. For the optical detection system, a precise estimation of the future values ​​is important because the future angular value can be coordinated with the timing of the optical signal emission from the optical detection system, e.g., a lidar system. By estimating half the future angular value, the number of scanned points in the vicinity of the optical detection system can be doubled. This allows for a further improvement in the quality of the detection result.

[0021] In one embodiment, the method further comprises estimating the rotational speed of the beam guidance device from the filtered values. For cases where the rotational speed of the beam guidance device is unknown, this makes it possible to obtain the rotational speed from the filtered values. The speed can be output and can also be used within the optical detection system and / or a vehicle in which the optical detection system may be contained.

[0022] In certain embodiments of the method, stored calibration data is used to obtain the angular values ​​of the beam guidance device's rotational movement. The accuracy of the angular values ​​can be improved by acquiring and applying the calibration data. This calibration data can be acquired during a calibration process prior to commissioning the beam guidance device. Accuracy measures how close a measured value is to the true or actual value.

[0023] In embodiments of the method, the alternating output of the first filtered values ​​and the second filtered values ​​is controlled using a finite state machine. The finite state machine is a computational model used to control the output, which at any given time can be in one of a finite number of states. The states of the finite state machine represent the different modes in which the output can be. For example, there can be a first state in which the first filtered values ​​are output, and there can be a second state in which the second filtered values ​​are output. The finite state machine further includes transitions. The transitions define how the system moves from one state to another. These transitions can be triggered by specific conditions or events and are, for example,associated with the change in output from the first filtered values ​​to the second filtered values. A condition for a transition could be, for example, that a state has been occupied for a certain period of time. An event for a transition could be, for example, that a buffer or stack is filled by one of the filters up to a certain level.

[0024] In certain embodiments of the method, the timing of alternating the output of the first filtered values ​​and the second filtered values ​​is controlled depending on the rate at which the values ​​are received. Values ​​arriving at a higher rate will fill the stack and buffers within the filters more quickly. This embodiment allows the output alternating to be adapted to such circumstances.

[0025] The first and / or second filter can use a sliding window filter for the filtering task. The sliding window filter will, in particular, allow for a more precise estimate of the future angle value and / or the further future angle value, since past values ​​influence the estimate.

[0026] The described optical detection system can be included in a vehicle.

[0027] A computer program product comprises instructions which, when executed by a control unit of an optical detection system, cause the control unit to perform the described procedure. The computer program product can, for example, correspond to a computer program containing the instructions, or to a computer-readable storage medium that stores the computer program containing the instructions. Short description of the characters

[0028] The embodiments are now described only by way of example, with reference to the attached drawings. Similar reference numbers are used throughout to refer to similar elements. The illustrated structures and devices are not necessarily drawn to scale. Fig. Figure 1 schematically illustrates a method for obtaining angular values ​​of a rotational motion. Fig. Figure 2 schematically illustrates a vehicle with an optical detection system. Fig. Figure 3 schematically illustrates an embodiment of the optical detection system with an embodiment of the beam guidance device. Fig. Figure 4 schematically illustrates another embodiment of the beam guidance device. Fig. Figure 5 schematically illustrates an angle position sensor. Fig. Figure 6 schematically illustrates values ​​that indicate measured angle values ​​as recorded by the angle position sensor. Fig. Figure 7 schematically illustrates an embodiment of a control unit designed to perform the described procedure. Detailed description

[0029] Fig. Figure 1 schematically illustrates a method for obtaining angular values ​​of a rotational movement of an optical beam steering device.

[0030] S1 receives values ​​VM that indicate measured angular values ​​of the rotational movement of the optical beam steering device.

[0031] In S2, the first filtered values ​​FV1 are obtained by filtering the received values ​​using a first filter F1. The first filter F1 can include a sliding window filter, where the sliding window filter uses past values ​​for the filtering process.

[0032] In S3, second filtered values ​​FV2 are obtained by filtering the received values ​​using a second filter F2. The second filter F2 can also include a sliding window filter.

[0033] In S4, the output of filtered values ​​FV is alternated by switching between the first filtered values ​​FV1 and the second filtered values ​​FV2. A plurality of first filtered values ​​FV1 is output alternately with a plurality of second filtered values ​​FV2. Preferably, the plurality of first filtered values ​​FV1 includes several consecutive first filtered values ​​FV1, and the plurality of second filtered values ​​FV2 includes several consecutive second filtered values ​​FV2. The alternating process is controlled using a finite state machine. The timing of the alternating can be adjusted depending on the rate at which the values ​​are received. The finite state machine can take this timing into account and adjust the rate of transition between the first filter output and the second filter output.

[0034] In S5, the filtered values ​​FV output are used to obtain the angular values ​​of the rotational motion, with the obtained angular values ​​being based on the received values. Calibration data CD, stored in a data store STO, can also be used to obtain the angular values ​​of the rotational motion. Using the calibration data CD improves the accuracy of the angular measurement.

[0035] In S6, the output filtered values ​​FV are used to estimate a future angle value relative to a future received value VM. Additionally, another future angle value, equal to half the future angle value, can be estimated using the output filtered values ​​FV.

[0036] In S7, the timing of the transmission of an optical signal L is controlled depending on the estimated angular values ​​of the rotational movement.

[0037] Furthermore, the rotational speed of the beam guidance device can be estimated using the filtered FV values ​​output.

[0038] Fig. Figure 2 schematically illustrates a vehicle 20, for example, a passenger car. The vehicle 20 includes an optical detection system 10, e.g., a lidar system. The optical detection system 10 is located in a front area of ​​the vehicle 20. It comprises an optical transmission device 12, an optical receiving device 14, the optical beam steering device 16, and a control unit 18. The control unit 18 may include a processor, a field-programmable gate array, or similar device for processing data.

[0039] The optical beam steering device 16 can be arranged such that it deflects the optical signal L, which is sent by the optical transmission device 12, into the detection area 22 and deflects the optical signal L, which is received from the detection area 22, to the optical receiving device 14. The optical beam steering device 16 can be controlled such that the optical signal L performs a scan movement 24 over the detection area 22. The optical beam steering device 16 can, for example, comprise a rotating mirror device that performs the rotational movement driven by a drive motor 30 in order to deflect the optical signal L so that the scan movement 24 is carried out by the optical signal L.

[0040] The control unit 18 can evaluate the transmitted and received optical signals L, for example, using time-of-flight measurements. This evaluation can be used to detect objects O in the detection area 22. The control unit 18 can also monitor and control the transmission process in the transmission device 12, the reception process in the receiving device 14, and / or the operation of the optical beam guidance device 16.

[0041] The optical detection system 10 can, for example, be located at or integrated into the front of the vehicle 20. The detection area 22 is then located in front of the vehicle 20. Thus, in the example shown, an area in the direction of travel in front of the vehicle 20 can be monitored by the optical detection system 10. Other optical sensor systems 10 are also possible for other parts of the vehicle 20, e.g., for all-round vision functions, such as on the sides and / or rear of the vehicle 20. It is also possible to arrange optical detection systems 10 and / or other sensor systems such as radar, ultrasound, etc., on the vehicle 20, particularly in corner areas of the vehicle 20.

[0042] The optical detection system 10 can be used to detect stationary or moving objects O within the detection range 22. Objects O can be vehicles, people, animals, plants, obstacles, road surface irregularities, especially potholes or stones, road boundaries, traffic signs, open areas, especially parking lots, precipitation, or the like.

[0043] For embodiments where the optical detection system 10 includes a lidar system, it can provide an accurate and dense detection point cloud of the detection area 22, which can show the contour of objects O, making it a very valuable sensor for, e.g., autonomous or semi-autonomous driving. Such a lidar system can detect, for example, lane markings, elevated objects that can be driven under, such as tunnels or overpasses, and the like.

[0044] Fig. Figure 3 shows a schematic block diagram of an embodiment of the optical detection system 10. The optical detection system 10 comprises the optical transmission device 12 and the optical receiving device 14, as well as the beam guidance device 16. The beam guidance device 16 includes a mirror connected to a drive shaft DS of the beam guidance device 16, enabling the beam guidance device 16 to rotate about an axis of rotation parallel to the drive shaft DS. The optical detection system 10 further includes the drive motor 30, which is connected directly or indirectly to the drive shaft DS to cause the rotation of the beam guidance device 16.

[0045] The mirror of the beam steering device can be a double-sided mirror that provides a surface for optical deflection of the optical signal L on both sides.

[0046] An angular position sensor 32, e.g., a rotary encoder, in particular a magnetic rotary encoder, is connected directly or indirectly to the drive shaft DS. For example, a motor shaft (not shown) of the drive motor 30 can be connected directly or indirectly to the drive shaft 30, or the drive shaft 30 can correspond to the motor shaft of the drive motor 30. The angular position sensor 32 is configured and designed to determine an angle of rotation of the motor shaft and therefore directly or indirectly the angle of rotation of the drive shaft 30, which in turn corresponds to an angular position of the beam guidance device 16.

[0047] The control unit 18 of the optical detection system 10 can control the drive motor drive 30 and the angle position sensor 32.

[0048] Fig. Figure 4 schematically illustrates another embodiment of the optical beam steering device 16 with the drive motor 30. The optical beam steering device 16 is arranged between the optical transmission device 12 and the optical receiving device 14 of the optical detection system 10. The optical transmission device 12 and the optical receiving device 14 can also be arranged on the same side of the optical beam steering device 16.

[0049] The Fig. The optical beam guidance device 16 shown in Figure 4 can rotate about its axis of rotation. One possible direction of rotation is shown in Figure 4. Fig. 4 is indicated by an arrow. The rotary motion is driven by the electric drive motor 30, which can drive a drive shaft DS arranged in the axis of rotation. The optical beam guiding device 16 can have four mirror surfaces on its side faces. In the example shown, each side face of the optical beam guiding device 16 has a mirror surface. The drive shaft DS can be arranged centrally in the optical beam guiding device 16.

[0050] The optical transmission device 12 is configured and arranged such that its transmitted optical signal L is deflected by the optical deflection device 16 in the direction of the detection area 22. The optical signal L reflected from the detection area 22 is deflected by the optical deflection device 16 in the direction of the optical receiving device 14.

[0051] Preferably, the optical transmission device 12 comprises a laser source for transmitting the optical signal L. The optical signal L can be pulsed.

[0052] The emission time of the pulses together with the angular position of the beam guidance device then influences the scan movement 24 of the optical detection system 10.

[0053] Preferably, the optical receiving device 14 comprises an optoelectronic detector, for example a point sensor, line sensor or area sensor, in particular an avalanche photodiode, a photodiode cell, a CCD sensor, an active pixel sensor, for example a CMOS sensor or the like. Optical signals, in particular laser signals, can be received by means of the optoelectronic detector and converted into electrical signals. The electrical signals can be processed, for example, by the control unit 18.

[0054] In optical detection systems 10, such as lidar systems, with a rotating mirror device as the optical beam steering device 16, the quality and precision of the control of the rotational movement of the optical beam steering device 16 is important. The rotating mirror can be used so that the optical signal L performs a scan 24 of the detection area 22. The measurement precision of the mirror's angle is important for the resulting precision of the point cloud that can be generated from the data acquired by the optical detection system 10. For a pulsed optical signal L, the precise angular position of the beam steering device 16 in relation to the timing of the emission of the individual pulses of the optical signal L is of particular importance.

[0055] To improve the accuracy of the measured angle values, it is therefore advantageous to calibrate the angle of rotation of the optical beam steering device 16. The calibration data can be stored in a lookup table in the STO data memory of the control unit 18 of the optical detection system 10 and / or a processor such as a field-programmable gate array of, for example, the optical beam steering device 16 and / or the drive motor 30. The lookup table can, for example, include an error value, which may be a correction value, for each measured angle.

[0056] Fig. Figure 5 schematically illustrates an embodiment of the angle position sensor 32. The angle position sensor 32 is an electromechanical device used to convert the angular position or movement of a rotating object into an electrical signal. It can be used to precisely and accurately monitor the rotary motion of the drive motor 30.

[0057] The angular position sensor 32 comprises a rotating object RO, which is a rotating mechanical part. The rotating object RO can also be referred to as a rotary encoder. The rotating object RO can be attached to the device that performs the rotary motion to be measured, e.g., the drive motor 30 or the beam guidance device 16. The rotating object RO can then perform the same rotary motion as the device being measured.

[0058] The rotating object RO can include a rotating ring containing alternating magnetic segments A and B, forming a pattern. Such a rotating object RO with magnetic segments can also be called a magnetic rotary encoder. The magnetic segments A can, for example, have the opposite magnetic polarity to the magnetic segments B. This pattern can be detected by an angle encoder ENC, and an electrical signal can be generated by the angle encoder ENC in response to the movement. The signal generated by the angle encoder ENC then indicates the angular position of the rotating object RO. The angle encoder ENC can, for example, comprise an integrated circuit.

[0059] The ENC angle encoder can be designed to generate more than one signal in response to the rotary motion. For example, two signals can be generated, one according to pattern A and the other according to pattern B. These signals are then shifted relative to each other by a fraction of a period. This can further improve and refine the result.

[0060] The rotating object RO of the angle position sensor 32 is mechanically coupled to the beam guidance device 16. For example, the rotating object can directly measure the rotation of the drive shaft DS of the beam guidance device 16 or of another shaft, such as the motor shaft of the drive motor 30 that drives the beam guidance device 16 and is mechanically coupled to the beam guidance device 16, for example, by means of one or more gears. In this way, the angular position of the beam guidance device 16 is translated into the angular position measured by the angle position sensor 32.

[0061] The angle position sensor 32 can also be implemented as a multi-turn absolute encoder that stores an index of rotations or total ranges of rotation angles. For example, the total range of rotation angles can correspond to a full 360° rotation of the corresponding shaft. An index signal or a tick of the index signal can then be generated each time the 360° have been completed, and each index can be stored, for example, so that the absolute position can be restored when the angle sensor is switched off and then on again.

[0062] The index signal I can be generated using the index track I, which is detected by the index sensor IS. The index sensor IS can then generate an index signal with an edge at each time the full rotation has occurred.

[0063] Fig. Figure 6 schematically illustrates values ​​that indicate measured angle values ​​as detected by the angle position sensor 32.

[0064] In Fig. Figure 6 shows electrical signals. There are rectangular pulse signals with a duty cycle of 0.5. The angular signals A and B are phase-shifted by 90° relative to each other. Each rising and falling edge of the first angular signal A, as well as each edge of the second angular signal B, represents a value that indicates the measured angle values.

[0065] The A signal corresponding to the A pattern and the B signal corresponding to the B pattern, both generated by the angle encoder ENC, are shown. The edges of the signals indicate the angular values ​​of the rotating object RO, which depend on the angular values ​​of the beam guidance device. The index signal corresponding to index I, as generated by the index sensor IS, is also shown.

[0066] The received values ​​VM can be incremental values, which in particular indicate increments d of angle values.

[0067] The control unit 18 can, for example, include an edge detector designed to determine a received value indicating measured angle values ​​according to time t0, t1, t2, ... t8 when a respective edge is detected.

[0068] The respective period of signals A, B is given as 4*d, and accordingly, the nominal time difference between two successive values ​​is d.

[0069] In the present example, the angle position sensor 32 also outputs the index signal I, which includes a positive pulse once every 360° of rotation and is otherwise equal to the logical 0.

[0070] It should be noted that Fig. Figure 6 shows an ideal situation, without noise or other distortions, e.g., due to temperature, in the angle signals A and B, and accordingly, the values ​​are evenly spaced by the nominal time difference d. In general, however, there will be deviations, especially jitter due to noise, distortion, etc.

[0071] Fig. Figure 7 schematically illustrates an embodiment of a control unit 18, which is used to perform the operation with reference to Fig. The procedure described in section 1 is designed for this purpose.

[0072] The control unit 18 receives values ​​indicating measured angles from the angle position sensor 32. As with reference to Fig. 5 and Fig. As described in section 6, these values ​​can be detected edges of the in Fig. The 6 signals shown correspond to the values ​​shown. The values ​​can also correspond to the edges in the Fig. 6 correspond to the signal shown, and the control unit 18 can include the edge detector to derive the values ​​from the in Fig. to detect the 6 signals shown.

[0073] The received values ​​are shifted using calibration data CDs stored in a data storage device STO of control unit 18. The calibration data CDs can be stored, in particular, in the form of a lookup table.

[0074] The first filter F1 and the second filter F2 perform the same filtering operation. Both apply a sliding window filter to the received values ​​VM, which are shifted by the calibration data CD. The sliding window filter considers past values ​​to calculate the increment d between two values. This increment can then be used to estimate a future angle value. This estimated future angle value can be used to time the emission of the optical signal by the optical transmission device 12.

[0075] The first and second filtered values ​​FV1, FV2, which are output by the first and second filters F1, F2, can therefore be angle values, estimated future angle values, or information regarding the angle values, such as incremental information.

[0076] The control unit 18 alternately switches between the output of the first and second filters F1 and F2, thus alternately outputting the first filtered values ​​FV1 and FV2. This enables continuous operation of the optical detection system 10, even when the amount of data to be processed by the first and second filters F1 and F2 is high due to high operating speed. One of the filters is in operation while the other can be reset. The first and second filtered values ​​can be continuously stored, thus preventing data loss. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102020132003A1

[0006]

Claims

[1] A method for obtaining angular values of a rotational movement of an optical beam steering device (16), comprising receiving values (VM) indicating measured angular values of the rotational movement, Obtaining first filtered values (FV1) by filtering the received values using a first filter (F1), Obtaining second filtered values (FV2) by filtering the received values using a second filter (F2), alternately outputting a plurality of first filtered values (FV1) and a plurality of second filtered values (FV2). [2] The method of claim 1, further comprising using the output filtered values (FV) to obtain the angle values of the rotational movement, wherein the obtained angle values relate to the received values. [3] The method of claim 1 or 2, wherein the plurality of first filtered values (FV1) comprises a plurality of consecutive first filtered values (FV1), and the plurality of second filtered values (FV2) comprises a plurality of consecutive second filtered values (FV2). [4] Method according to one of the preceding claims, wherein the received values (VM) are incremental values, which in particular indicate increments (d) of angle values. [5] A method according to any one of the preceding claims, further comprising: Using the output filtered values (FV) to estimate a future angle value related to a future received value (VM) and / or to estimate another future angle value equal to half the future angle value. [6] The method of claim 5, further comprising: Controlling the timing of a transmission of an optical signal (L) depending on the estimated angular values of the rotational movement. [7] Method according to one of the preceding claims, further comprising estimating the speed of the rotational movement from the filtered values (FV). [8] Method according to one of the preceding claims, wherein stored calibration data (CD) are used to obtain the angular values of the rotational movement. [9] Method according to one of the preceding claims, wherein the alternating output of the first filtered values (FV1) and the second filtered values (FV2) is controlled using a finite state machine. [10] A method according to claim 9, wherein the timing of the alternating output of the first filtered values (FV1) and the second filtered values (FV2) is controlled in dependence on the speed at which the values are received. [11] A method according to any one of the preceding claims, wherein the first and / or second filter (F1, F2) uses a sliding window filter. [12] Optical detection system (10) comprising an optical beam steering device (16) and a control unit (18), wherein the optical beam steering device (16) is designed to perform a rotational movement, and wherein the control unit (18) is designed to Receiving values (VM) that indicate measured angular values of the rotational movement, Obtaining first filtered values (FV1) by filtering the received values using a first filter (F1), Obtaining second filtered values (FV2) by filtering the received values using a second filter (F2), alternately outputting a plurality of first filtered values (FV1) and a plurality of second filtered values (FV2). [13] Optical detection system (10) according to claim 12, wherein the control unit (18) is designed to use the output filtered values (FV) to obtain the angular values of the rotational movement, wherein the obtained angular values relate to the received values. [14] Optical detection system (10) according to claim 13, wherein the control unit (18) is designed to control the timing of a transmission of an optical signal (L) in dependence on the angular values of the rotational movement. [15] Vehicle (20) comprising the optical detection system (10) according to any one of claims 12 to 14. [16] A computer program product comprising instructions which, when executed by a control unit (18) of an optical detection system (10), cause the control unit (18) to perform a method according to any one of claims 1 to 11.

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