A LIDAR system, a method for a LIDAR system, and a receiver for a LIDAR system having first and second conversion elements

Abstract

A receiver (100, 235, 400, 520, 600, 700) for a system (200, 500) for light detection and distance measurement, LIDAR, the receiver having the following features: a plurality of sensing elements (115, 565), each sensing element having one or more members (125a, 125b, 125c, 130a, 130b) configured to convert light (110) into an electrical signal, each sensing element configured to provide an analog sensing signal (120a, 120b, 120c, 120d) in response to a laser pulse emitted by a transmitter (210, 510) of the LIDAR system (200, 500); a number of conversion elements (140a, 140b, 140c, 650), each of which is configured to provide a respective first digital detection signal (142a, 142b, 142c) in response to a respective first analog detection signal (120a, 120b, 120d) provided by at least one of the plurality of detection elements (115, 565), wherein the respective first conversion element (140a, 140b, 140c, 650) is configured to use a first number of bits to represent the respective first analog detection signal (120a, 120b, 120d); at least one second conversion element (150a, 150b, 675) configured to provide a second digital detection signal (152a, 152b) in response to a second analog detection signal (120b, 120c) provided by at least one of the plurality of detection elements (115, 565), wherein the second conversion element (150a, 150b, 675) is configured to use a second number of bits to represent the second analog detection signal (120b, 120c), wherein the second number of bits is greater than the first number of bits, wherein the number of first conversion elements (140a, 140b, 140c, 675) is higher than a number of second conversion elements (150a, 150b, 675); and a processing module (160, 698) configured to determine at least a first parameter (112a) of an object in a target area of ​​the LIDAR system (200, 500) using the first digital detection signals (142a, 142b, 142c) and a second parameter of the object using the second digital detection signal (152a, 152b).

Description

Technical area

[0001] This application relates to light detection and ranging (LIDAR) applications. More specifically, it relates to a LIDAR system, a method for a LIDAR system, and a receiver for a LIDAR system having conversion elements that provide digital detection signals in response to analog detection signals. The analog signals are provided by detection elements having members that convert light into electrical signals in response to a laser pulse emitted by a transmitter of a LIDAR system. Background of the invention

[0002] LIDAR systems illuminate objects in a target area with laser light and measure the reflected light with a sensor. The time of flight of the laser light correlates with the distance between a LIDAR system and the objects in the target area. The intensity of the sampled light allows the reflectivity of the objects to be determined. The reflected laser light is typically sampled by photodiodes, whose electrical current is amplified and prepared for conversion to the digital domain. After raw sensor data is collected, signal processing is applied to obtain a 3D point cloud.

[0003] Multibit analog-to-digital converters are generally used for signal amplitude analysis, for example, to detect lane markings in automotive applications. High sampling rates are used for precise range resolutions; for example, a sampling rate of 1.5 GHz is used for a range resolution of 10 cm. The number of analog-to-digital converters in a LIDAR system, their resolution, and sampling rate contribute to the computational resources utilized and the power dissipation of the LIDAR system.

[0004] DE 10 2016 224 509 A1 describes a receiver arrangement for receiving at least one light pulse and outputting a received signal, in which the received signal is used for object detection. At least two evaluation devices are provided for determining the time of flight of the at least one light pulse, each of which uses different evaluation methods, with the received signal being derived from the time of flight.

[0005] EP 3 130 890 A1 discloses a measuring device with a plurality of pixels of a detection area, wherein each of the plurality of pixels is connected to an evaluation device. The measuring device has a multiplexer for selectively forwarding detection signals from a plurality of pixels to an evaluation device.

[0006] US 2017 / 0 176 578 A1 discloses a distance measurement device with an array of light-sensitive detectors, the array comprising a number of different zones. The device includes a readout circuit for reading output data from the respective zones.

[0007] EP 2 182 378 A1 shows a distance-measuring laser scanner with a light-receiving element as well as an analog-to-digital converter and a memory for digitizing and recording a received signal from the light-receiving element. Brief description of the invention

[0008] A flexible approach for converting signals sampled in a LIDAR system into their digital representation for further processing is desirable.

[0009] Examples of the disclosure provide a receiver for a light detection and ranging (LIDAR) system. The receiver includes a plurality of sensing elements. Each sensing element includes one or more members configured to convert light into an electrical signal. Each sensing element is configured to provide an analog sensing signal in response to a light pulse emitted by a transmitter of the LIDAR system. The receiver includes a number of conversion elements, each of which is configured to provide a respective first digital sensing signal in response to a respective first analog sensing signal provided by at least one of the plurality of sensing elements.The respective first conversion element is configured to use a first number of bits to represent the respective first analog detection signal. The receiver has at least one second conversion element configured to provide a second digital detection signal in response to a second analog detection signal provided by at least one of the plurality of detection elements. The second conversion element is configured to use a second number of bits to represent the second analog detection signal. The second number of bits is greater than the first number of bits. The number of first conversion elements is higher than a number of second conversion elements.The receiver comprises a processing module configured to determine at least a first parameter of an object in a target area of ​​the LIDAR system using the first digital detection signals and a second parameter of the object using the second digital detection signal.

[0010] Examples of the disclosure provide a method for operating a receiver of a light detection and ranging (LIDAR) system. The system includes the step of providing, by each of a plurality of sensing elements, an analog sensing signal in response to a laser pulse emitted by a transmitter of the LIDAR system, each sensing element having one or more members configured to convert light into an electrical signal. The method further includes the step of providing, by each of a number of first conversion elements, a respective first digital sensing signal in response to a respective first analog sensing signal provided by at least one of the plurality of sensing elements.The respective first conversion element uses a first number of bits to represent the respective first analog detection signal. The method further comprises the step of providing, by at least one second conversion element, a second digital detection signal in response to a second analog detection signal provided by at least one of the plurality of detection elements. The second conversion element uses a second number of bits to represent the second analog detection signal. The second number of bits is greater than the first number of bits. The number of first conversion elements is higher than a number of second conversion elements.The method further comprises the step of determining, by a processing module, at least a first parameter of an object in a target area of ​​the LIDAR system using the first digital detection signals and a second parameter of the object using the second digital detection signal.

[0011] The dual use of conversion elements with a different number of bits to represent the respective analog detection signals in a receiver of a LIDAR system advantageously allows for balancing the efforts related to processing complexity and power dissipation, as well as the resolution of the digital conversion with respect to the number of bits used to determine a respective parameter or multiple respective parameters of an object in the target area of ​​the LIDAR system. Examples of the present disclosure may allow for the use of conversion elements whose resolution most appropriately corresponds to the resolution required to determine a desired parameter, e.g., detection, ranging, or reflectivity. The utilization of processing resources and power dissipation may be advantageously improved.

[0012] In other words, a hybrid architecture (e.g., 1-bit / ADC architecture) according to examples of the disclosure can address conflicting requirements between detection / ranging and reflectivity measurements: On the one hand, a fine time resolution for ranging and oversampling / averaging (e.g., sending laser pulses multiple times to the same target to improve the signal-to-noise ratio) for detection (but a low amplitude resolution) can be achieved, and on the other hand, a high amplitude resolution for measuring reflectivity (but a lower time resolution and averaging) can be achieved. Short description of the characters

[0013] Examples of the disclosure are described below with reference to the accompanying figures, in which: Fig. 1 shows a schematic block diagram of a receiver for a LIDAR system according to an example; Fig. 2 shows a schematic block diagram of a LIDAR system according to an example; Fig. 3 shows a flowchart of a method for operating a LIDAR system according to an example; Fig. 4 shows a schematic block diagram of a receiver for a LIDAR system according to an example; Fig. 5 shows a 1D scanning LIDAR system according to an example; Fig. 6 shows a receiver of a LIDAR system according to an example; Fig. Figure 7 shows another example of a receiver of a LIDAR system; Fig. 8 out of Fig. 8 (a), which schematically shows a 1-bit processing chain, and Fig. 8 (b) - (f) are diagrams showing exemplary signals in the 1-bit processing chain according to an example; Fig. 9 out of Fig. 9 (a), which schematically shows a multibit processing chain, and Fig. 9 (b) - (f) are diagrams showing exemplary signals in the multibit processing chain according to an example; Fig. 10 schematically shows exemplary signals associated with the low-pass filter (LP filter) according to an example; Fig. 11 shows an exemplary timing diagram for a receiver according to an example; Fig. 12 shows another exemplary timing diagram for a receiver according to an example; Fig. 13 shows another exemplary timing diagram for a receiver according to an example; Fig. 14 shows another exemplary timing diagram for a receiver according to an example; Fig. 15 shows an exemplary target area (scene) of a LIDAR system according to an example; Fig. 16 from Fig. 16 (a), which shows a partial point cloud profile with target points of interest (POI), and Fig. 16 (b), which illustrates fast POI sampling with two ADCs, according to one embodiment. Detailed description of the characters

[0014] Fig. Figure 1 schematically shows a receiver 100 for a LIDAR system. The receiver responds to light 110 reflected from an object in the target area of ​​the LIDAR system (not shown) and provides a first parameter 112a of the object and a second parameter 112b of the object. The receiver 100 includes a plurality of sensing elements 115. Each sensing element provides an analog detection signal 120a, 120b, 120c, 120d in response to receiving a reflected laser pulse 110. The signals 120a, 120b, and 120d are each provided by a single member 125a, 125b, and 125c, respectively, that converts light 110 into an electrical signal. The signal 120c is provided by two components 130a and 130b which are connected to each other (e.g. in parallel).

[0015] The receiver 100 further includes three first conversion elements 140a, 140b, 140c. The conversion element 140a provides a first digital detection signal 142a in response to an analog detection signal 120a provided by the conversion element 140a; the conversion element 140b provides a first digital detection signal 142b in response to the analog detection signal 120b; and the conversion element 140c provides a first digital detection signal 142c in response to the analog detection signal 120d. The digital detection signals 142a, 142b, 142c have a first resolution, i.e., they use a first number of bits to represent the analog detection signals. According to one example, the first resolution may be 1 bit and the conversion elements 140a, 140b, 140c may be comparators.

[0016] The receiver 100 further includes two second conversion elements 150a, 150b. The conversion element 150a provides a second digital detection signal 152a in response to the analog detection signal 120b; the conversion element 150b provides a second digital detection signal 152b in response to the analog detection signal 120c. The second conversion elements 150a, 150b use a second number of bits to represent the respective analog detection signals. In other words, the second conversion elements 150a, 150b have a second resolution. According to one example, the second resolution may be 8 bits, and the conversion elements 150a, 150b may be multi-bit analog-to-digital converters.

[0017] It can be seen that the specific connections between acquisition elements and conversion elements in Fig. 1 are for illustrative purposes only and may vary in other examples. In examples, the receiver may include switches, e.g., multiplexers, that enable selective switching of the output signals of each of the detection elements 125a, 125b, 125c, 130a, 130b to one of the first conversion elements 140a, 140b, 140c, to one of the second conversion elements 150a, 150c, or to both.

[0018] In addition, the receiver 100 includes a processing module 160. The processing module 160 determines the first parameter 112a of the object in the target area of ​​the LIDAR system using the first digital detection signals 142a, 142b, 142c. Furthermore, the detection module 160 determines the second parameter 112b of the object in the target area of ​​the LIDAR system using the second digital detection signals 152a, 152b. According to one example, the first parameter 112a may be a detection parameter or a ranging parameter, and the processing module determines the first parameter using the 1-bit digital detection signals 142a, 142b, 142c. The second parameter 112b may be a reflectivity parameter and may be determined by the processing module 160 using the 8-bit digital detection signals 152a, 152b.

[0019] According to one example of the disclosure, the first conversion element may be a comparator that uses one bit to represent the first digital detection signal, and / or the second conversion element may be an analog-to-digital converter that uses two or more bits to represent the second digital detection signal. This example may advantageously allow for determining respective parameters, e.g., detection and ranging, with a low effort in terms of silicon resources and power dissipation through the use of a comparator and / or determining respective parameters, e.g., reflectivity, with a higher effort and higher resolution through the use of an analog-to-digital converter.

[0020] According to one example of the disclosure, the first analog detection signal and the second analog detection signal may be provided by the same one of the plurality of detection elements. This example may advantageously allow signals provided by the same detection element to be digitized using two different resolutions, for example, depending on the parameter to be determined.

[0021] According to one example of the disclosure, a number of the first conversion elements may be lower than a number of the plurality of sensing elements, and the receiver may further comprise at least one first multiplexer coupled to a first subset of sensing elements comprising two or more of the plurality of sensing elements and configured to switch the analog sensing signal of one of the sensing elements in the first subset to the first conversion element. This example may advantageously allow the sensing elements to share a conversion element, rather than requiring a separate conversion element for each sensing element.

[0022] According to one example of the disclosure, a number of the second conversion elements may be lower than a number of the plurality of sensing elements, and the receiver may further comprise a second multiplexer coupled to a second subset of sensing elements comprising two or more of the plurality of sensing elements and configured to switch the analog sensing signal of one of the sensing elements in the second subset to the second conversion element. This example may advantageously allow the sensing elements to share a conversion element, rather than requiring a separate conversion element for each sensing element.

[0023] According to one example of the disclosure, the first subset of sensing elements and the second subset of sensing elements may comprise the same sensing elements as the plurality of sensing elements. This example may advantageously allow signals provided by the same sensing elements to be digitized using two different resolutions, for example, depending on the parameter to be determined.

[0024] According to one example of the disclosure, the second multiplexer may be configured to switch the analog detection signal of another of the detection elements, to which the second multiplexer is coupled, to the second conversion element for each laser pulse of a plurality of laser pulses transmitted to a position in the target area during a measurement period. This example may advantageously allow the detection elements to share a conversion element.

[0025] According to one example of the disclosure, the first multiplexer may be configured to switch the analog detection signal of a selected one or more of the detection elements to which the first multiplexer is coupled to the first conversion element for each laser pulse of a plurality of laser pulses transmitted to a position in the target area during a measurement period. This example may advantageously allow the detection elements to flexibly share the first conversion element.

[0026] According to one example of the disclosure, the second multiplexer may be configured to switch the analog detection signal of a selected one or more of the detection elements to which the second multiplexer is coupled to the second conversion element for each laser pulse of a plurality of laser pulses transmitted to a position in the target area during a measurement period. This example may advantageously allow the detection elements to flexibly share the second conversion element.

[0027] According to one embodiment of the disclosure, the receiver may further comprise a selection module configured to select the selected one or more of the sensing elements to be switched by the first multiplexer and / or to the second multiplexer using a region of interest in the target area of ​​the LIDAR system. This example may advantageously allow the available conversion elements to be focused on a selected region in the target area.

[0028] According to one example of the disclosure, the selection module may be configured to determine the region of interest using previous ones of the first and / or second digital acquisition signals. This example may advantageously allow for the use of available knowledge about the target area acquired in the past to determine the region of interest.

[0029] According to one example of the disclosure, the processing module may be configured to use an average of the first digital detection signals and / or the second digital detection signals of the selected ones of the detection elements obtained for the plurality of laser pulses emitted to the position in the target area during the measurement period. This example may advantageously allow the available detection elements to be used for averaging, which may result in an improved signal-to-noise ratio.

[0030] According to one example of the disclosure, the plurality of laser pulses emitted during the measurement period may include two or more or all of the laser pulses emitted for a single angular setting of the LIDAR system. This example may advantageously allow any of the advantages described herein, e.g., multiplexing, to be used for a single spatial setting of a LIDAR system.

[0031] According to one example of the disclosure, the second multiplexer may be configured to switch the analog acquisition signal of selected ones of the acquisition elements to which the second multiplexer is coupled to the second conversion element during a measurement period associated with a single laser pulse transmitted to a position in the target area. This example may advantageously enable extended multiplexing and sharing of a conversion element between the acquisition elements at a fine time granularity.

[0032] According to one example of the disclosure, the receiver may further comprise a selection module configured to select the selected one of the sensing elements using previous ones of the first and / or second digital sensing signals and / or the first digital sensing signal and / or a number of the second conversion elements. This example may advantageously allow for the use of available historical knowledge about the target area, the current measurement performed at a lower resolution, and information about available sensing elements with a higher resolution for multiplexing decisions.

[0033] According to one example of the disclosure, the second parameter may be a reflectivity parameter, and the processing module may be configured to use the first digital detection signal in determining the reflectivity parameter. This example may advantageously allow the determination of the reflectivity parameter to be enhanced by using information obtained at a lower resolution, e.g., about the location of possible reflective objects.

[0034] According to one example of the disclosure, the first parameter may be a detection parameter and / or a ranging parameter, and the processing module may be configured to use the second digital detection signal in determining the detection parameter and / or the ranging parameter. This example may advantageously allow the determination of the detection parameter and / or the ranging parameter to be enhanced by using information obtained at a higher resolution, such as conversion elements.

[0035] According to one example of the disclosure, the receiver may further comprise at least one analog low-pass filter upstream of the second conversion element, wherein the analog low-pass filter is configured to low-pass filter the second analog detection signal before the second analog detection signal is supplied to the second conversion element. This example may advantageously enable a reduction in the noise floor and / or sampling frequency for the second conversion element.

[0036] According to one example of the disclosure, the processing module may be configured to at least partially compensate for a modification in the second digital acquisition signal of the second conversion element introduced by the analog low-pass filter by using an inverse transfer function of the analog low-pass filter. This example may advantageously allow for reducing the impact of the low-pass filter on the specific parameter.

[0037] According to one example of the disclosure, the receiver may further comprise at least one digital low-pass filter downstream of the second conversion element, wherein the digital low-pass filter is configured to low-pass filter the second digital detection signal provided by the second conversion element. This example may advantageously enable noise reduction for determining the second parameter.

[0038] According to one example of the disclosure, the processing module may be configured to at least partially compensate for a modification in the second digital acquisition signal of the second conversion element introduced by the digital low-pass filter by using an inverse transfer function of the digital low-pass filter. This example may advantageously allow reducing the impact of the low-pass filter on the particular parameter. In examples, the processing module may be configured to at least partially compensate only for the delay introduced by the digital low-pass filter.

[0039] According to one example of the disclosure, a sampling rate of the first conversion element may be higher than a sampling rate of the second conversion element. This example may advantageously allow for saving resources, such as silicon resources and / or computing power.

[0040] According to one example of the disclosure, the processing module may be configured to use an average of the first digital detection signals obtained for a plurality of laser pulses emitted to a position in the target area during a measurement period. This example may advantageously enable improving a signal-to-noise ratio and / or permit detection of peaks in signals digitized with a low number of bits.

[0041] Fig. 2 schematically shows a LIDAR system 200. The LIDAR system 200 includes a transmitter 210 with a laser 215 and a deflector 220. The deflector 220 deflects the laser beam 225 of the laser 215 to different positions 230a, 230b within the target area of ​​the LIDAR system 200. The laser beam 225 is reflected by one or more objects at the different positions 230a, 230b within the target area of ​​the LIDAR system 200. A receiver 235 included in the LIDAR system 200 receives the reflected laser beam 225. The receiver 235 may include any of the features, functionalities, and details described herein. The features, functionalities, and details may be used individually or in combination to define the receiver of the LIDAR system.

[0042] Fig. 3 shows a flowchart of a method 300 for operating a receiver for a LIDAR system. The method 300 includes a step 310 of providing, by each of a plurality of sensing elements, an analog sensing signal in response to a laser pulse emitted by a transmitter of the LIDAR system, wherein each sensing element includes one or more members configured to convert light into an electrical signal. Furthermore, the method 300 includes the step 320 of providing, by at least a first conversion element, a first digital sensing signal in response to a first analog sensing signal provided by at least one of the plurality of sensing elements, wherein the first conversion element uses a first number of bits to represent the first analog sensing signal.The method 300 further includes the step 330 of providing, by at least one second conversion element, a second digital detection signal in response to a second analog detection signal provided by at least one of the plurality of detection elements, wherein the second conversion element uses a second number of bits to represent the second analog detection signal, wherein the second number of bits is greater than the first number of bits. In addition, the method 300 includes the step 340 of determining, by a processing module, at least a first parameter of an object in a target area of ​​the LIDAR system using the first digital detection signal and a second parameter of the object using the digital detection signal.

[0043] The method 300 may optionally be supplemented by any of the features, functionalities, and details disclosed herein, including with respect to the devices.

[0044] The method 300 can optionally be supplemented both individually and in combination by such features, functionalities and further details.

[0045] Fig. Figure 4 schematically shows a receiver 400 for a LIDAR system. The receiver 400 comprises several elements described above with regard to Fig. 1. These elements of the receiver, already described above, are assigned the same reference numerals and are not described again here.

[0046] The receiver 400 includes a first multiplexer 460. The first multiplexer 460 is coupled to a subset of the sensing elements, namely those sensing elements that provide the first analog sensing signals 120b and 120d. The first multiplexer 460 provides an output signal 462, which is provided to the first conversion element 140b. The first multiplexer 460 selectively switches one of the signals 120b and 120d to the conversion element 140b.

[0047] Additionally, receiver 400 includes a second multiplexer 470 coupled to a subset of the sensing elements, namely those providing the second analog sensing signals 120b and 120c. The second multiplexer 470 provides an output signal 472, which is provided to the second conversion element 150a. The second multiplexer 470 selectively switches one of the signals 120b and 120c to the conversion element 150a.

[0048] It can be seen that the specific connections between acquisition elements, multiplexers and conversion elements in Fig. 4 are for illustrative purposes only and may vary in other examples. In general, examples may provide multiplexers that enable selective switching of the analog sensing signal of each of the sensing elements to either a first analog-to-digital converter having the first resolution or a second analog-to-digital converter having the second resolution, or both.

[0049] Fig. 5 shows an exemplary 1D scanning LIDAR system 500. The system 500 includes a transmitter 510 and a receiver 520. The transmitter 510 illuminates a portion of the scene 530 with a laser beam 535 (e.g., a vertical laser beam). In one example, the laser beam 535 may have a wavelength of 905 nm. The reflected laser beam 535, which is reflected from objects in the scene 530, is received at the receiver 520 and processed to obtain a digital representation of the scene 530.

[0050] The transmitter 510 includes a plurality of strip lasers 540. The individual beams of the lasers 540 are focused by a lens system 545 and deflected by a 1D MEMS mirror 550, which is an example of a deflector. The transmitter is controlled by a controller (not shown), which causes the 1D MEMS mirror 550 to oscillate and assume different angular positions with respect to the axis 555, so that the scene 530 is scanned (e.g., horizontally). The lasers 540 are controlled by a controller (not shown) such that pulsed laser beams 535 illuminate the scene 530. According to one example, the individual pulses of the lasers may have a duration on the order of a few nanoseconds, e.g., 10 ns.

[0051] Receiver 520 includes optics 560 and a 2D detector array 565. Optics 560 focuses the light reflected from scene 530 onto 2D detector array 565. 2D detector array 565 converts the received light into electrical signals. 2D detector array 565, along with analog circuitry such as filters, amplifiers, and the like, is an example of sensing elements of the present invention. Detector array 565 may include a plurality of avalanche photodiodes, which may also be referred to as APDs (avalanche photo diodes), arranged in a 2D array. Different individual elements of the 2D array along the vertical direction, i.e., the direction in which the vertical laser beams 535 extend, correspond to different vertical positions in the scene 530 (i.e., different fields of view). Different individual elements of the 2D array 565 along the horizontal direction (i.e.,different columns) are used for different ranges of the angular position of the mirror 550, i.e. for different horizontal sections of the scene 530.

[0052] The 2D detector array 565 is connected to a processing module (not shown). The processing module receives the electrical signals provided by the 2D detector array 565 and uses analog and digital signal and data processing to provide a digital representation of the scene 530. The digital representation of the scene includes a plurality of points to which parameters such as detection, ranging, and reflectivity can be assigned. More specifically, for an individual angular position of the mirror 550, a laser pulse is emitted, and the electrical signals provided by the 2D detector array 565 are recorded and sampled for a predetermined period of time to obtain light reflected from the objects in the target area. According to one example, the recording time may have a duration on the order of a few microseconds, e.g., 2 µs.The digital representation of the electrical signals provided by the 2D detector array 565 is subjected to digital signal processing, which may include averaging and thresholding.

[0053] Fig. 6 shows an example of the connection with Fig. 5. It should be noted that the elements of the receiver 520 already described above are assigned the same reference numerals and are not described again here.

[0054] The Fig. The receiver 600 shown in Figure 6 includes an analog portion 605 with a 2D detector array 565 and outputs 615. Elements of the 2D detector array are connected to the outputs 615. Application-specific transimpedance amplifier integrated circuits (TIA-ASICs) include multiplexers 610, TIA channels 630, and multiplexers 640. The elements of array 565 are connected to the multiplexers 610 via outputs 615 such that multiplexing can be performed between the elements of array 565 and the TIA channels 630. The outputs 615 of the analog portion 605 are connected to inputs of TIA-ASICs 625, each of which includes a plurality of TIA channels 630. The TIA channels 630 provide a voltage that corresponds to, e.g., is proportional to, the current provided to the TIA channels 630 by the elements of the array 565. The outputs of the TIA channels 630 are provided to the outputs 635 of the TIA ASICs 625.The outputs of TIA channels 630 are also provided to the multiplexers 640. Outputs of the multiplexers 640 are provided to outputs 645 of the TIA ASICs 625.

[0055] The outputs 635 of the TIA ASICs 625 are provided to comparators 650. Each comparator 650 converts an input signal provided to it into a 1-bit digital representation of the input signal. Specifically, each comparator 650 compares its input to a threshold and provides a digital output signal, for example, with a value of 1, if the input is greater than or equal to the threshold, and provides another digital output signal, for example, with a value of 0, if the input is lower than the threshold. The digital signals provided by the comparators 650 are processed by 1-bit processing chains, each of which includes an averaging element 655, a matched filter element 660, a detection element 665, and a ranging element 670.A 1-bit processing channel corresponds to one vertical field of view (FoV) for a horizontal 1D scanning LIDAR system, but a vertical 1D scanning LIDAR system is also envisioned. The functionality of the 1-bit processing chain is described below in conjunction with . Fig. 8 described.

[0056] The outputs 645 of the TIA ASICs 625 are each provided to analog-to-digital converters (ADCs) 675. Each ADC 675 converts an input signal provided to it into a multibit representation of the input signal. The number of bits used to represent an input signal, i.e., the number of output bits of an ADC, is also referred to as the resolution of the ADC. According to one example, the ADCs 675 may have a resolution of 8 bits. The digital signals provided by the ADCs 675 are processed by ADC processing chains, each of which includes a buffer element 680, a low-pass element 685, and a reflectivity element 690. Low-pass elements 685a may optionally be provided in addition to (or as an alternative to) the low-pass elements 685. The operation of the multibit processing chain is described below in connection with Fig. 9 and Fig. 10 described.

[0057] The multi-bit processing chain and the 1-bit processing chain can optionally be interconnected. In one example, the output of the detection elements 665 can optionally be provided to the reflection element 690. In this example, knowing when a reflection has been detected allows reducing the bandwidth of the reflectivity measurements, improving the signal-to-noise ratio and the accuracy of the reflectivity measurement. Knowing when a reflection has been detected can be based on histogramization in the 1-bit chain, for example, in the detection element 665.

[0058] In another example, the multi-bit data may be considered for detection and / or ranging, for example, in the detection elements 665 and / or in the ranging elements 670. The data from the 1-bit path and the multi-bit path may be combined (joined), for example, after averaging. In one example, data considered for ranging / detection may be defined as avg(1-bit data) + weight *(multi-bit data), where avg() refers to an averaging operation, weight is a predetermined or dynamic weighting coefficient, and multi-bit data refers to ADC data or any other data in the multi-bit processing chain.

[0059] The outputs of the distance measurement elements 670 and the reflectivity elements 690 are provided to a point cloud generation element 695. The elements 655, 660, 665, 670, 680, 685, 690, and 695 may collectively (or individually) be referred to as a processing module 698. The digital signal processing elements such as 655, 660, 665, 670, 680, 685, 690, and 695 of Fig. 6 can be implemented in a field-programmable gate array (FPGA) or a microcontroller (µC). However, it is clear that different implementations are provided for each of the elements 655, 660, 665, 670, 680, 685, 690, and 695, for example, in an ASIC or a signal processor.

[0060] While a 1-bit digital-to-analog conversion in the processing chain consists of Fig. 6, which includes the detection and ranging elements 665, 670, a different number of bits may be used to digitize the output signals 635. However, it is generally advantageous to use a lower number of bits for the processing chains including the detection and ranging elements 665, 670 compared to the number of bits for the processing chains including the reflectivity elements 690. An analog-to-digital conversion with a lower number of bits uses fewer resources, e.g., consumes less power, uses less silicon area, etc., and may still allow the desired parameters, such as detection / ranging, to be determined.

[0061] In Fig. 6 illustrates three overlapping blocks, indicating that one or more corresponding blocks may be used. The multiplexers in the TIA ASIC(s) can be divided into sub-areas. The components can be distributed across integrated circuits in various ways. Regarding the low-pass filters, 685 and 685a are optional; that is, in a practical scenario, either the low-pass filter 685 or the low-pass filter 685a is provided, but not both.

[0062] Fig. 7 shows another example of the Fig. 5 described receiver of the LIDAR system 500. It should be noted that the receiver already described above in connection with Fig. 5 and Fig. 6 described elements of the receiver are assigned the same reference numerals and are not described again. According to Fig. 7, a receiver 700 comprises Y first converters 750 with a lower resolution and X second converters 775 with a higher resolution, where Y and X are positive integers. In general, Y may be greater than X. The first converters may be comparators with a resolution of 1 bit, and the converters 775 may be ADCs with a resolution of 8 bits.

[0063] The Fig. The receiver 700 shown in Figure 7 comprises a 2D detector array 565, which may comprise K x L detector elements. The signals from each of the plurality of M elements of the array 565 are provided to one of circuits 725a, 725b, for example ASICs, each of which has a plurality of M TIA channels. Each of the circuits 725a, 725b comprises a first multiplexer such that Y of the M input signals 723a, 723b are switched to the Y output signals 727a, 727b, respectively. The Y signals 727a, the Y signals 727b (or both) are then provided to Y comparator channels 750, which are provided to the 1-bit comparator 650 in Fig. 6. The circuits 725a, 725b can perform multiplexing on the outputs 727a and 727b.

[0064] Each of the circuits 725a, 725b further comprises a second multiplexer such that X of M input signals 723a, 723b are switched to the X output signals 729a, 729b, respectively. Both signals 729a, 729b can be low-pass filtered in a low-pass filter element 751 and provided to X ADC channels that are applied to the ADCs 675 in Fig. 6 correspond.

[0065] The outputs of the Y-channel comparator block 750 and the X-channel ADC block 775 are provided to an FPGA 797 with corresponding digital signal processing (DSP) channels. The outputs of the FPGA 797 are provided to a microcontroller 799. The FPGA 797 and the microcontroller 799 can individually or jointly implement the Fig. Implement the functionalities described in section 6.

[0066] Fig. 8 consists of Fig. 8 (a), which schematically shows a 1-bit processing chain of a single channel, and Fig. 8 (b) - (f), which show diagrams illustrating exemplary signals in the 1-bit processing chain. It should be noted that the above-mentioned Fig. 5 to 7, the same reference numerals are assigned to the elements of the receiver and are not described again.

[0067] The Fig. The processing chain shown in Figure 8(a) includes an APD 565, a TIA 630, a comparator 650, an averaging element 655, a matched filter / slicing element 660, and a ranging / reflectivity element 670. The averaging element 655 is configured to calculate an average resulting from the analog detection signals received in response to a plurality of laser pulses or shots transmitted during the measurement period.

[0068] Fig. Figure 8 (b) shows a plurality of waveforms, each illustrating an output current of an element of the ACD 565. The waveforms extend from time 0 to time 2 µs, which corresponds to the acquisition time of the LIDAR system used in conjunction with Fig. 5. A noise floor is visible approximately between the lowest ordinate shown and the current of 5 µA. At a time point designated as t1, a peak with a current of approximately 11 µA is visible. Each waveform shows one of the several measurements taken for an individual angular position of the Fig. 5 shown mirror 550.

[0069] Fig. Figure 8 (c) shows a plurality of waveforms for the measurements for the individual angular positions of the mirror 550, each waveform consisting of Fig. 8 (c) a waveform in Fig. 8 (b). Each waveform shows the output current of the TIA 630. Similar to the Fig. The waveforms shown in Figure 8 (b) show the Fig. 8 (c) show a noise floor approximately between the lowest ordinate shown and the voltage just below 0.2 V. The peak at time t1 has a value of approximately 0.7 V.

[0070] Fig. Figure 8 (d) shows a plurality of waveforms for the measurements for the individual angular position of the mirror 550, each waveform consisting of Fig. 8 (d) a waveform in Fig. 8 (b) and Fig. 8 (c). Fig. Figure 8 (d) shows the output of comparator 650. Since comparator 650 is a 1-bit comparator, the output of comparator 650 only takes the values ​​0 or 1. At time t1, a change in the behavior of the waveforms due to averaging is visible.

[0071] Fig. Figure 8(e) shows a waveform which is an output of comparator 650 after averaging in block 655. Again, the peak at time t1 is visible. Fig. 8 (f) shows the signal curve from Fig. 8 (e) after filtering in the optimal filter / cutter element 660. Fig. 8 (e) additionally shows a threshold line 810, with which the signal curve from Fig. 8 (f) to detect the ranging parameter, ie, a distance from the LIDAR system to an object in the target area of ​​the LIDAR system.

[0072] The peak with a value of approximately 1 is separated from the noise floor in element 660 and / or 670 by using threshold line 810. The time t1 of the peak at approximately 0.35 µs is the time between the emission of the laser pulse by the transmitter 510 of the LIDAR system 500 and the detection of the reflected laser pulse by the receiver of the LIDAR system 500. This time corresponds to a distance of approximately 100 m traveled by light at the speed of light. The detected distance between an object and the LIDAR system is therefore approximately 50 m.

[0073] Determining the detection and / or ranging parameter using a 1-bit processing chain can be advantageous compared to using a multi-bit processing chain. Compared to a multi-bit processing chain, the 1-bit processing chain uses fewer resources, e.g., silicon resources (i.e., FPGA resources), and has lower power dissipation. Additionally, the performance of determining detection and / or ranging using the 1-bit processing chain is typically only slightly degraded compared to the performance using a multi-bit processing chain.

[0074] Fig. 9 consists of Fig. 9 (a), which schematically shows a multibit processing chain of a single channel, and Fig. 9 (b) - (f), the diagrams show exemplary signals of the individual processing elements of the multi-processing chain from Fig. 9 (a). The above in connection with Fig. The elements of the receiver described in Figures 5 to 8 are assigned the same reference numerals and are not described again.

[0075] The Fig. The processing chain shown in Figure 9(a) includes an APD 565, a TIA 630, an analog-to-digital converter 675, an averaging element 902, a matched filter / slicing element 905, and a ranging / reflectivity element 690. The averaging element 655 is optional and may be configured to calculate an average resulting from the analog detection signals received in response to a plurality of laser pulses or shots transmitted during the measurement period.

[0076] Fig. 9 (b) shows - similar to the one described above Fig. 8 (b) - a plurality of waveforms, each illustrating an output current of an element of the APD 565. The length of the waveforms is 2 µs, which is the exemplary acquisition time of the above-mentioned Fig. 5 discussed LIDAR system. Each of the Fig. 9 (b) results from a measurement (alternatively from a simulation) for an individual angular position of the mirror 550, which in conjunction with Fig. 5 has been discussed. Fig. Figure 9 (b) shows a noise floor between the lower ordinate shown and the current of approximately 5 µA. At a time point labelled t1, Fig. 9 (b) a peak is visible. The peak has a current value of approximately 11 µA.

[0077] Fig. 9 (c) shows - similar to the above-described Fig. 8 (c) - a plurality of voltage waveforms, each waveform showing an output voltage of the TIA 630 in response to an input current of the element of the APD 565 according to a Fig. 9 (b). Similar to the waveform shown in Fig. 9 (b) show the current signal waveforms in Fig. The waveforms shown in Figure 9 (c) exhibit a noise floor originating at the lowest ordinate shown and a voltage of 0.2 V. The peak at time t1 exhibits a voltage of approximately 0.7 V.

[0078] Fig. 9 (d) shows - similar to the above-described Fig. 8 (d) - the outputs of the analog-to-digital conversion in the element 675. The Fig. The exemplary analog-to-digital conversion shown in Figure 9 (d) has a resolution of 8 bits. The digital representation can generally take values ​​between 0 and 255, whereas the ordinate of the diagram in Fig. 9 (d) is limited to approximately 140. The peak at time t1 has the value of approximately 130. It should be noted that the peak in Fig. 9 (d) compared to Fig. 8 (d) amplitude information, ie the above-mentioned value of 130, whereas the waveforms of the 1-bit conversion in Fig. 8 (d) can only take one of the two values ​​0 or 1. Therefore, the digital data provided by the multibit processing chain are suitable for determining, for example, a reflectivity parameter of an object in the target area of ​​the LIDAR system.

[0079] Fig. Figure 9(e) shows a waveform that is an output of the averaging element 902. Averaging is optionally performed for multiple laser pulses for a given angular position of the mirror 550. The averaging can be a full averaging with a sampling rate corresponding to the sampling rate of the averaging in element 655 of the 1-bit string, or a reduced averaging with a sampling rate lower than the sampling rate of element 655.

[0080] The peak at time t1 is in Fig. 9 (e) visible. Fig. 9 (f) shows the waveform from Fig. 9 (e) after processing in the optimal filter / cutter element 905. Fig. Figure 9 (e) additionally shows a threshold line 910, which allows the multibit processing chain to separate the noise floor from the peak at time t1. The exemplary peak value of 130 at time t1 may correspond to a reflectivity of 10% in one example.

[0081] In some examples, the Fig. 9 shown multibit processing chain with a lower sampling rate compared to that used in conjunction with Fig. 8 and Fig. 9 The processing discussed above can be performed in the 1-bit processing chain. This can advantageously save resources such as silicon resources and / or computing power.

[0082] Fig. Figure 10 schematically shows exemplary signals associated with the low-pass filters (LP filters) 685, 685a, which in conjunction with Fig. 6 discussed above. Fig. Figure 10 (a) shows an exemplary waveform for a 1-bit processing chain; Fig. Figure 10 (b) shows a corresponding waveform for a multibit processing chain. The waveforms in Fig. 10 (a) and Fig. 10 (b) are plotted over time as the independent variable; the ordinates in Fig. 10 (a) and Fig. 10 (b) refer to signal amplitudes.

[0083] The waveform in Fig. 10 (a) shows a signal peak 1010 at time t1. The signal peak may correspond to a measured reflection from an object in the target area of ​​the LIDAR system. Based on the Fig. 10 (a), the detection element 665 and / or the distance measuring element 670 determines a distance of the object in the target area based on the determined time of the signal peak, ie, based on the time t1. The distance is determined as above in connection with Fig. 8 described.

[0084] The waveform in Fig. 10 (b) has a signal peak 1020. The signal peak 1020 is a result of low-pass filtering using the filter elements 685, 685a. The filtering changes the amplitude of the original signal (which in Fig. 10 (b) using the designation “A_LP”) and / or introduces a time delay or a phase delay (which is indicated in Fig. 10 (b)) using the notation "t_LP"). In the example, the change in the signal in the LP element 685 is (at least partially) compensated for by the signal processing, for example, in the reflectivity element 695. More specifically, the filtered signal can be processed using the inverse transformation of the LP filter.

[0085] Although the LP filter element 685 has been described as a digital filter downstream of the ADCs 675, the low-pass filtering may instead or additionally occur in the analog domain. In one example, an analog low-pass filter 685a may be located upstream of the ADCs 675, for example, in the signal path between the multiplexers 645a, 645b and the ADCs 645a, 645b. It should be noted that in the case of the analog implementation of the LP filter, compensation for the signal changes introduced by the analog filter may be implemented in the digital domain, for example, similarly to that described above in connection with the digital LP filter element 685.

[0086] The use of a digital LP filter enables economical implementation and simple configuration (e.g., the filter can be deactivated and / or its cutoff frequency can be changed, for example, during operation of the LIDAR system by software implemented in the LIDAR system controller). The use of an analog LP filter can reduce the sampling frequency requirements for the ADCs. A combination of analog and digital filtering can be optimal for specific LIDAR system requirements in terms of performance, cost, etc.

[0087] With reference to Fig. Figures 11 to 14 now describe timing diagrams that show examples of how analog acquisition signals from a number of acquisition elements can be applied to first and second converters. The application of the signals or channels to the respective converters can be achieved by appropriately switching the multiplexers. Fig. 11 to 14, the time course lies in the horizontal direction, as indicated by an arrow 1105. The numbers -3, -2, -1, 0, 1, etc. below the arrow 1105 denote the time course in arbitrary units. A time range 1110 shows the time selection for a first angle, i.e., a first angular position of the mirror 550, and a time range 1115 shows the time selection for a second angle, i.e., a second angular position of the mirror 550. The first angle may differ from the second angle, for example, in the case where the time ranges 1110 and 1115 belong to the same frame. Alternatively, the first and second angles may correspond to the same mechanical position of the mirror 550 if the time ranges 1110 and 1115 belong to different frames.

[0088] Each time range 1110 and 1115 is further divided into sub-time ranges 1110a, 1110b, 1110c, 1110d and 1115a, 1115b, 1115c, 1115d. The curved double lines in Fig. Figures 11 to 14 indicate that not all sub-ranges are shown for clarity. Each of the sub-ranges corresponds to the acquisition time for a single laser pulse of the LIDAR system. In other words, each time sub-range includes the emission of the laser pulse by the transmitter 510 (e.g., for 10 ns) and the corresponding acquisition of the reflected light by the receiver 520 (e.g., for 2 ns). Each time range can be considered to be associated with a laser shot.

[0089] As in connection with Fig. 11 to 14, the term "channel" refers to a respective TIA channel in which a detection signal originating from a detection element is amplified. For example, CH1 refers to a signal received from a first detection element via a first TIA channel, CH2 refers to a signal received from a second detection element via a second TIA channel, and CHi refers to a signal received from an i-th detection element via an i-th TIA channel.

[0090] In the left part of the Fig. 11 to 14, a converter is shown to which the signal of a respective sensing element, i.e., channel, is applied. In the examples shown, the first converter with the lower resolution is a comparator, and the second converter with a higher resolution is an ADC. As indicated above, a receiver according to examples of the present disclosure may include Y number of first converters, e.g., comparators, and X number of second converters, e.g., ADCs. In examples of the present disclosure, Y is higher than X.

[0091] Accordingly, Fig. 11 to 14, which acquisition signals are applied to which converters in the respective time sub-ranges. For example, in Fig. 11 in sub-area 1110a, channel CH1 is applied to the first ADC as indicated at 1120, and in sub-area 1110b, channel CH2 is applied to the first ADC as indicated at 1135.

[0092] Fig. 11 shows a schematic multiplexing scheme of an exemplary receiver with X number of ADCs and Y comparators. According to the example shown, each time domain 1110, 1115 is divided into Y / X subdomains 1110a-1110d, 1115a-1115d. In each of the subdomains, a different channel is applied to each of the ADCs, i.e., channels CH1 to CH2Y / X are applied to the first ADC, as shown at line 1120, channels CH(X / Y)+1 to CH2Y / X are applied to the second ADC, as shown at line 1125, etc. Finally, channels CH1Y-X+1 to CH2Y are applied to the Xth ADC, as shown at line 1130. Therefore, there is one shot per channel for the higher resolution converters, i.e., the ADCs. As with lines 1140, 1145 and 1150 in Fig. As shown in Figure 11, the same channel is applied to each of the comparators in all sub-ranges 1110a to 1110d (and also 1115a to 1115d). In the example shown, the first channel is applied to the first comparator, as shown at 1155a, 1155b, 1155c, and 1155d. Thus, in the example shown, there are Y / X shots per channel for averaging for the comparators. This pattern can be repeated in the next time range 1115.

[0093] In the example from Fig. 11, the channel applied to each of the ADCs is changed in each sub-range, shot, of a time domain. The channel applied to the comparator during the time domain is averaged over the time domain. In one example, the number of comparators may equal the number of TIA channels. The number of ADCs may be two and the number of comparators may be thirty-two. In other examples, the ratio may be different. The number of sub-ranges of each range, and therefore the number of shots averaged for each comparator, depends on the ratio between Y and X.

[0094] It should be noted that the multiplex patterns do not apply to the ones shown in lines 1120, 1125 and 1130 in Fig. 11. Rather, any multiplexing pattern may be used, for example, based on the area of ​​interest of the LIDAR system, knowledge of the objects in the target area from, for example, previous frames, or processing of the current frame. The contemplated patterns include using different channels in each time sub-range to obtain reflectivity for the greatest possible number of channels. The contemplated patterns include using the same channel for a number of time sub-ranges to enable averaging for that channel and improve the signal-to-noise ratio for that channel. All mixed types of the multiplexing schemes described above are considered to be within the scope of the present invention.

[0095] With reference to the above-described Fig. 7, it should be noted that multiplexing is generally also provided for the 1-bit channels. As explained above, using circuits 725a, 725b, the signals 723a, 723b can be switched to the comparator channels 750. As described above, any multiplexing pattern provided for the multi-bit channels can also be used for the 1-bit channels. Selective use of one or more regions of interest, sampling of the most possible positions in the target region, and / or channel averaging can be applied.

[0096] Fig. Figure 12 shows an exemplary timing diagram for the receiver 600 or the receiver 700 as described above in connection with Fig. 6 and Fig. 7. It should be noted that the elements already described above are assigned the same reference numerals and will not be described again.

[0097] Fig. 12 shows exemplary multiplexing schemes according to examples of the present disclosure. Different channels are applied to the respective ADCs in different subdomains. The pattern in which channels are applied to the respective ADCs for a first angle may differ from the channels applied to the respective ADCs for a second angle. For example, as shown at 1205a and 1205b, for the first angle of the mirror 550 of the LIDAR system, i.e., for the time domain 1110, a channel CH2 is applied to the first ADC in subdomains 1110a and 1110b. A channel CH3 may be applied to the first ADC in a subdomain 1110d, as shown at 1205c. A channel CH3 can be applied to the second ADC in all sub-ranges of a time domain 1110, as shown at 1215a, 1215b and 1215c.As shown at 1215d, 1215e, and 1215f, a channel CH7 can be applied to the X-th ADC in a sub-area 1110a, a channel CH8 can be applied to the X-th ADC in a sub-area 1110b, and a channel CH11 can be applied to the X-th ADC in a sub-area 1110d. As shown at 1220a, 1225a, 1225c, 1230a, 1230b, and 1230d, different channels, e.g., channels CH1 and CHY, can be applied to the ADCs for the second angle. Thus, FIG. Fig. 12, that channels can be applied to the respective ADCs in an arbitrary and selective manner, ie, multiplexed or switched.

[0098] The timing diagram with respect to lines 1140, 1145, 1150 from Fig. 12 is above in connection with Fig. 11 and will not be described again.

[0099] Fig. 13 shows an exemplary timing diagram for an example of a receiver according to the present disclosure in which full averaging is used. The elements already described above are assigned the same reference numerals and will not be described again.

[0100] As in line 1120 and in 1305a, 1305b, 1305c, 1305d in Fig. 13, the channel applied to the first ADC remains the same in all sub-areas 1110a, 1110b, 1110c, and 1110d. In the example shown, there are sixteen shots for each channel, as indicated by #1 to #16, associated with each of the channels in Fig. 13. The signals received during these shots can be averaged. A similar behavior is shown in the remaining blocks of rows 1120 and 1125. More specifically, in the example shown, a channel CH2 is applied to the first ADC in a first time domain 1110, a channel CH6 is applied to an ADC2 in the time domain 1110, a channel CH4 is applied to the first ADC in a time domain 1115, and a channel CHY is applied to the second ADC in the time domain 1115. In other words, the multiplexing takes place only at the edges of the time domains corresponding to the respective angles of the mirror 555, rather than during the periods for measurements for the individual angles. Performing multiple measurements for a single channel makes it possible to average, for example, in the digital domain, and thus improve the signal-to-noise ratio. In other words, the Fig. The timing diagram shown in Figure 13 illustrates the use of power averaging instead of multiplexing. Fig. In the example shown in Figure 13, an averaging factor of 16 is used. In other examples, other averaging factors may be used for the high-resolution channel(s). For example, two high-resolution channels may be multiplexed to the same transducer with half-scale averaging. The high-resolution channels for full averaging may be selected based on the acquisition results of previous acquisitions. For example, channels indicating a target in a previous acquisition may be selected for full-resolution averaging to obtain additional information about the target.

[0101] The example in Fig. Figure 12 shows a potential implementation of an ROI (region of interest) based on a priori knowledge, e.g., from previous frameworks. The example in Fig. 13 concentrates the full ADC processing power on one channel. The example in Fig. 11 distributes the full ADC processing power across all channels. The example in Fig. 12 is an intermediate solution between the two other approaches. It distributes the full ADC processing power across a selected number of channels.

[0102] Fig. 14 shows an exemplary timing diagram for a receiver according to the present disclosure. The elements already described above are assigned the same reference numerals and will not be described again.

[0103] Fig. 14 shows a portion of the time domain 1110 corresponding to the first angular position of the mirror 550 of the LIDAR system, which in conjunction with Fig. 11 to 13. In Fig. 14 shows the time sub-regions 1110a, 1110b, and a portion of the time sub-region 1110c. The elements already described above are assigned the same reference numerals and will not be described again.

[0104] In the Fig. In the timing diagram shown in Figure 14, the multiplexing occurs at a time granularity that is finer than the time granularity of the time sub-ranges 1110a, 1110b, 1110c. In other words, in a recording time (measurement period) associated with a single laser pulse of the LIDAR system, different channels are applied to the ADCs 675. For example, blocks 1405, 1410, and 1415 illustrate that "CH1" is applied to the first ADCs 675 for approximately 1 / 3 of the recording time (1 / 3 of the time sub-range 1110b). "CH3" is applied to the first ADC for approximately 1 / 3 of the recording time, and "CHY" is applied to the first ADC for 1 / 3 of the recording time. Blocks 1420, 1425, and 1430 illustrate that "CH5" is applied to the X-th ADC for 1 / 2 of the acquisition time (1 / 3 of the time sub-range 1110b), "CHY" is applied to the second ADC for a short time, and then "CH3" is applied to the second ADC for approximately 1 / 3 of the acquisition time.

[0105] It should be noted in general that the multiplexers 640 can switch different channels to the respective ADCs 675 at any time. The fractions of the acquisition time described above (two sub-ranges 1110b) are intended for illustrative purposes.

[0106] Switching the ADC inputs during an acquisition time of the single laser pulse allows for a large number (e.g., maximum number) of averagings, which in turn can lead to improved ranging / reflectivity performance.

[0107] Fig. Figure 15 shows an exemplary target area (scene) of the LIDAR system 500. The exemplary target area is directed toward a possible application of the LIDAR system 500 as an automotive sensor. The target area includes a road with lane markings, with two people standing at one edge of the road, a ball at another edge of the road, and grass verges adjacent to the road. The horizontal dimension of the area illuminated by the laser of the LIDAR system 500 is identified using arrow 1505; the vertical dimension of the illuminated area is identified using arrow 1510.

[0108] The entire illuminated area is covered by vertical stripes, three of which are designated as 1515. Each vertical stripe represents a vertical laser beam 535 for a specific angular position of the mirror 550. The vertical stripes in Fig. 15 illustrates an area sampled and evaluated using 1-bit processing to provide detection and / or ranging parameters without a reflectivity measurement.

[0109] Fig. Figure 15 shows sections of the illuminated area, three of which are designated as 1520 by way of example. These sections define a region of interest (ROI) for which reflectivity measurements are performed using multibit processing. For example, for a number of ADCs 675 that is a factor x less than the number of individual elements of the 2D array 535 along the vertical direction (as in connection with Fig. 5 above), 1 / x of the vertical illuminated area (i.e., 1 / x of the vertical FoV) may be sampled using the ADCs 675 to determine the reflectivity parameter. In one example, 1 / 2 averaging may be performed for 2 / x of the vertical FoV. In another example, full averaging may be performed for 1 / x of the vertical FoV (assuming × ADCs).

[0110] In one example, a selection module of the LIDAR system 500 determines the ROI and selects a suitable multiplexing. More specifically, the selection module determines which TIA channels are switched from the multiplexers 640 to the ADCs 675 for which angular position of the mirrors and at which times. In other words, the selection module determines a schedule for the multiplexers that corresponds to the requirements described above in connection with Fig. may be similar to the schedules described in paragraphs 11 to 14.

[0111] The selection module may determine the ROI based on predetermined parameters of the LIDAR system 500, e.g., settings that determine certain angles as the ROI. Alternatively or additionally, the selection module may determine the ROI using prior knowledge of the illuminated scene obtained by the LIDAR system 500. The prior knowledge may include evaluation results of the previous frames / scans. Alternatively or additionally, the prior knowledge may include evaluation results of the current frame / scan obtained from the 1-bit processing chain.

[0112] Fig. 16 consists of Fig. 16 (a) and Fig. 16 (b). Fig. 16 (a) shows a partial point cloud profile with target points of interest (POI); Fig. Figure 16 (b) illustrates fast POI sampling with two ADCs.

[0113] Fig. Figure 16 (a) shows four waveforms A 1610, B 1615, C 1620, and D 1625, each of which corresponds to an acquisition time of the LIDAR system 500. The scene has four targets, namely Target 1 1630, Target 2 1635, Target 3 1640, and Target 4 1645. A 1-bit sampling subsystem creates a profile of a (e.g., partial) point cloud for target POls. Fig. Figure 16 (a) also shows channels CH1 1650 and CH2 1655. Part of target 4 1645 is partially obscured (e.g., hidden or blurred) by target 2.

[0114] Fig. Figure 16(b) illustrates an additional sample (or multiple samples) scheduled, for example, by the selection module for the ADCs 675 to sample the POIs (or ROIs) in the (e.g., partial) point cloud. The multiplexers 640 switch rapidly from pixel to pixel during a measurement (e.g., in real time). In other words, a multi-bit processing chain (one ADC channel) is changed by the selection module during a single acquisition time for individual laser pulses, exploiting knowledge of the expected arrival time. The (e.g., a priori) knowledge can be obtained from an evaluation of the 1-bit channel (or channels) or from a previous frame (or multiple previous frames). The ADCs 675 record a signal peak in the profiled window to estimate the reflectivity in the element 690. The reflectivity parameter (or alternatively the amplitude) is provided (transmitted) with a point cloud pixel time of flight (TOF). Fig. Figure 16(b) shows recording windows 1660 and 1665 scheduled by the selection module for multiplexers 640 and ADCs 675, respectively. The switching pattern for a multiplexer 640 is shown by arrows 1670. The selection module may also consider the number of available ADCs and schedule a window to be sampled in the next pass (e.g., a next frame) due to the lack of available ADCs in the current frame.

[0115] It should be understood that the receiver, LIDAR system, and method of the present invention are not limited to the 1D oscillating mirror according to the examples described above. Rather, the present invention could also be applied to other approaches, such as a flash LIDAR, a 2D mirror LIDAR, or the like. In other words, reference to the 1D oscillating mirror LIDAR in this patent application is for illustrative purposes only.

[0116] Further examples of the disclosure are described below. The examples described below may constitute alternatives or may be considered additional to the aspects disclosed above.

[0117] The following describes an architecture with regard to a specific implementation using 32 channels and 16x oversampling. It should be noted that the invention can be used for a variety of applications.

[0118] The system can be divided as follows: - 2 channels with 8-bit processing chain without oversampling - 32 channels with 1-bit processing chain with 16x oversampling

[0119] 1-bit processing can fire 16 times at the same FoV. During this time, 2-channel ADCs can be used to switch the 32 channels and record one shot per FoV. This means that the 1-bit signal chain can exploit full parallelism to perform as large averaging as possible, while high-resolution ADCs can use the minimum number of parallel channels to record at least one shot per frame.

[0120] The following enhancements can be implemented (individually or in combination). - 8-bit / 1-bit data streams can be merged and used for ranging / sensing to improve performance; - 1-bit converters and multiplexing can be implemented with external components; - 1-bit processing can be implemented with a higher sampling rate compared to the ADC; - The high-resolution (ADC) channels can perform oversampling (but reduced compared to the 1-bit architecture); - The high-resolution channel can use an additional low-pass filter to further reduce the bandwidth. This reduces the noise level and can make the reflectivity measurement more accurate (the reduced gain can be compensated in post-processing).

[0121] Although some aspects have been described in the context of an apparatus, it will be understood that where a block or component corresponds to a method step or a feature of a method step, these aspects also represent a description of the corresponding method. Analogously, aspects described in the context of a method step also represent a description of a corresponding block, component, or feature of a corresponding apparatus. Some or all of the method steps may be performed by (or using) a hardware device, e.g., a microprocessor, a programmable computer, or an electronic circuit. In some examples, one or more of the key method steps may be performed by such a device.

[0122] Depending on specific implementation requirements, examples of the invention may be implemented in hardware or software. The implementation may be carried out using a digital storage medium, e.g., a floppy disk, a DVD, a Blu-ray disc, a CD, a ROM, a PROM, an EPROM, an EEPROM, or a FLASH memory with electronically readable control signals stored thereon that cooperate (or are capable of cooperating) with a programmable computer system such that the corresponding method is carried out. Therefore, the digital storage medium may be computer-readable.

[0123] In general, examples of the disclosure may be implemented as a computer program product with program code, wherein the program code is operable to perform one of the methods when the computer program product is executed on a computer. The program code may, for example, be stored on a machine-readable medium.

[0124] Other examples include the computer program for carrying out any of the methods described herein stored on a machine-readable medium.

[0125] In other words, therefore, an example of the disclosure is a computer program having program code for performing one of the methods described herein when the computer program is executed on a computer.

[0126] A further embodiment of the disclosed methods is therefore a data carrier (or a digital storage medium or a computer-readable medium) having recorded thereon the computer program for carrying out one of the methods described herein. The data carrier, the digital storage medium, or the recorded medium is typically tangible and / or non-transitory.

[0127] A further example of the disclosed methods is therefore a data stream or a sequence of signals representing the computer program for executing one of the methods described herein. The data stream or the sequence of signals can, for example, be configured to be transmitted via a data communication connection, e.g., via the Internet.

[0128] Another example includes a processing device, e.g., a computer, or a programmable logic device configured or adapted to perform one of the methods described herein.

[0129] Another example includes a computer having the computer program installed for performing any of the methods described herein.

[0130] Another example of the disclosure includes a device or system configured to transmit a computer program (e.g., electronically or optically) for performing one of the methods described herein to a recipient. The recipient may, for example, be a computer, a mobile device, a memory device, or the like. The device or system may, for example, include a file server for transmitting the computer program to the recipient.

[0131] In some examples, a programmable logic device (e.g., a field-programmable gate array) may be used to perform some or all of the functionality of the methods described herein. In some examples, a field-programmable gate array may cooperate with a microprocessor to perform any of the methods described herein. In general, the methods are preferably performed by any hardware device.

[0132] The apparatus described herein may be implemented using a hardware device or using a computer or using a combination of a hardware device and a computer.

[0133] The device described herein, or any component of the device described herein, may be implemented at least partially as hardware or software.

[0134] The methods described herein may be implemented using a hardware device or using a computer or using a combination of a hardware device and a computer.

[0135] The methods described herein, or any component of the methods described herein, may be implemented at least partially in hardware or software.

[0136] The examples described above are merely illustrative of the principles of the present invention. It is to be understood that modifications and variations of the arrangements and details described herein will be apparent to others skilled in the art. Therefore, it is intended that the invention be limited only by the scope of the appended claims and not by the specific details presented in the description and explanation of the examples herein.

Claims

[1] A receiver (100, 235, 400, 520, 600, 700) for a system (200, 500) for light detection and distance measurement, LIDAR, the receiver having the following features: a plurality of sensing elements (115, 565), each sensing element having one or more members (125a, 125b, 125c, 130a, 130b) configured to convert light (110) into an electrical signal, each sensing element configured to provide an analog sensing signal (120a, 120b, 120c, 120d) in response to a laser pulse emitted by a transmitter (210, 510) of the LIDAR system (200, 500); a number of conversion elements (140a, 140b, 140c, 650), each of which is configured to provide a respective first digital detection signal (142a, 142b, 142c) in response to a respective first analog detection signal (120a, 120b, 120d) provided by at least one of the plurality of detection elements (115, 565), wherein the respective first conversion element (140a, 140b, 140c, 650) is configured to use a first number of bits to represent the respective first analog detection signal (120a, 120b, 120d); at least one second conversion element (150a, 150b, 675) configured to provide a second digital detection signal (152a, 152b) in response to a second analog detection signal (120b, 120c) provided by at least one of the plurality of detection elements (115, 565), wherein the second conversion element (150a, 150b, 675) is configured to use a second number of bits to represent the second analog detection signal (120b, 120c), wherein the second number of bits is greater than the first number of bits, wherein the number of first conversion elements (140a, 140b, 140c, 675) is higher than a number of second conversion elements (150a, 150b, 675); and a processing module (160, 698) configured to determine at least a first parameter (112a) of an object in a target area of ​​the LIDAR system (200, 500) using the first digital detection signals (142a, 142b, 142c) and a second parameter of the object using the second digital detection signal (152a, 152b). [2] The receiver (100, 235, 400, 520, 600, 700) according to claim 1, wherein the first conversion elements (140a, 140b, 140c, 650) are comparators that use one bit to represent the first digital detection signal (142a, 142b, 142c) and / or the second conversion element (150a, 150b, 650) is an analog-to-digital converter that uses two or more bits to represent the second digital detection signal (152a, 152b). [3] The receiver (100, 235, 400, 520, 600, 700) according to one of claims 1 or 2, wherein the first analog detection signal (120a, 120b, 120d) and the second analog detection signal (120b, 120c) are provided by the same one of the plurality of detection elements (115). [4] The receiver (100, 235, 400, 520, 600, 700) according to any one of the preceding claims, wherein the number of first conversion elements (140a, 140b, 650) is less than a number of the plurality of detection elements (115), and the receiver further comprises at least one first multiplexer (460) coupled to a first subset of detection elements comprising two or more of the plurality of detection elements (115) and configured to switch the analog detection signal (120b, 120d) from one of the detection elements in the first subset to one of the first conversion elements (140b). [5] The receiver (100, 235, 400, 520, 600, 700) according to any one of the preceding claims, wherein the number of the second conversion elements (150a, 150b, 675) is lower than a number of the plurality of detection elements (115), and the receiver further comprises at least one second multiplexer (470, 640) coupled to a second subset of sensing elements (115) comprising two or more of the plurality of sensing elements, and configured to switch the analog sensing signal (120b, 120c) from one of the sensing elements in the second subset to the second conversion element (150a, 675). [6] The receiver (100, 235, 400, 520, 600, 700) according to claim 4 and 5, wherein the first subset of sensing elements and the second subset of sensing elements comprise the same of the plurality of sensing elements (115). [7] The receiver (100, 235, 400, 520, 600, 700) according to claim 5 or 6, wherein the second multiplexer (470, 640) is configured to switch, for each laser pulse of a plurality of laser pulses emitted to a position in the target area during a measurement period, the analog detection signal (120b, 120c) of a different one of the detection elements to which the second multiplexer (470, 640) is coupled to the second conversion element (150a, 675). [8] The receiver (100, 235, 400, 520, 600, 700) according to claim 4 or 6, wherein the first multiplexer (460) is configured to switch, for each laser pulse of a plurality of laser pulses transmitted to a position in the target area during a measurement period, the analog detection signal (120b, 120d) of a selected one or more of the detection elements to which the first multiplexer (460) is coupled to one of the first conversion elements (140b). [9] The receiver (100, 235, 400, 520, 600, 700) according to claim 5 or 6, wherein the second multiplexer (470, 640) is configured to switch, for each laser pulse of a plurality of laser pulses emitted to a position in the target area during a measurement period, the analog detection signal (120b, 120c) of a selected one or more of the detection elements to which the second multiplexer (470, 640) is coupled to the second conversion element (150a, 675). [10] The receiver (100, 235, 400, 520, 600, 700) according to one of claims 8 or 9, wherein the receiver further comprises a selection module configured to select the selected one or more of the sensing elements to be switched by the first multiplexer (460) and / or the second multiplexer (470, 640) using a region of interest in the target area of ​​the LIDAR system (200, 500). [11] The receiver (100, 235, 400, 520, 600, 700) of claim 10, wherein the selection module is configured to determine the region of interest using previous ones of the first and / or second digital detection signals (142a, 142b, 142c, 152a, 152b). [12] The receiver (100, 235, 400, 520, 600, 700) according to any one of claims 8 to 11, wherein the processing module is configured to use an average of the first digital detection signals (142a, 142b, 142c) and / or the second digital detection signals (152a, 152b) of the selected ones of the detection elements obtained for the plurality of laser pulses emitted to the position in the target area during the measurement period. [13] The receiver (100, 235, 400, 520, 600, 700) according to any one of claims 7 to 12, wherein the plurality of laser pulses emitted during the measurement period comprises two or more or all of the laser pulses emitted for a single angular adjustment of the LIDAR system. [14] The receiver (100, 235, 400, 520, 600, 700) according to claim 5 or 6, wherein the second multiplexer (470, 640) is configured to switch the analog detection signal (120b, 120c) of selected ones of the detection elements to which the second multiplexer (470, 640) is coupled to the second conversion element during a measurement period associated with a single laser pulse emitted to a position in the target area. [15] The receiver (100, 235, 400, 520, 600, 700) according to claim 14, wherein the receiver further comprises a selection module configured to select the selected ones of the detection elements using previous ones of the first and / or second digital detection signals and / or the first detection signal (142a, 142b) and / or a number of the second conversion elements (150a, 675). [16] The receiver (100, 235, 400, 520, 600, 700) according to any one of the preceding claims, wherein the second parameter (112b) is a reflectivity parameter, and the processing module (160, 698) is configured to use the first digital detection signal (142a, 142b, 142c) in determining the reflectivity parameter. [17] The receiver (100, 235, 400, 520, 600, 700) according to any one of the preceding claims, wherein the first parameter (112a) is a detection parameter and / or a ranging parameter, and the processing module (160, 698) is configured to use the second digital detection signal (152a, 152b) in determining the detection parameter and / or the ranging parameter. [18] The receiver (100, 235, 400, 520, 600, 700) according to any one of the preceding claims, wherein the receiver (100, 235, 400, 520, 600, 700) further comprises at least one analog low-pass filter (685a) upstream of the second conversion element (675), wherein the analog low-pass filter (685a) is configured to subject the second analog detection signal (120b, 120c) to low-pass filtering before the second analog detection signal is supplied to the second conversion element (150a, 150b, 675). [19] The receiver (100, 235, 400, 520, 600, 700) according to claim 18, wherein the processing module (160, 698) is configured to at least partially compensate for a modification in the second digital detection signal (152a, 152b) of the second conversion element (150a, 150b, 675) introduced by the analog low-pass filter (685a) by using an inverse transfer function of the analog low-pass filter (685a). [20] The receiver (100, 235, 400, 520, 600, 700) according to any one of the preceding claims, wherein the receiver further comprises at least one digital low-pass filter (685) downstream of the second conversion element (675), wherein the digital low-pass filter (685) is configured to subject the second digital detection signal (152a, 152b) provided by the second conversion element (150a, 150b, 675) to low-pass filtering. [21] The receiver (100, 235, 400, 520, 600, 700) according to claim 20, wherein the processing module (160, 689) is configured to at least partially compensate for a modification in the second digital detection signal (152a, 152b) of the second conversion element (150a, 150b, 675) introduced by the digital low-pass filter (685) by using an inverse transfer function of the digital low-pass filter (685). [22] The receiver (100, 235, 400, 520, 600, 700) according to any one of the preceding claims, wherein a sampling rate of the first conversion elements (140a, 140b, 140c, 650) is higher than a sampling rate of the second conversion element (150a, 150b, 675). [23] The receiver (100, 235, 400, 520, 600, 700) according to any one of the preceding claims, wherein the processing module (160, 698) is configured to use an average of the first digital detection signals (142a, 142b, 142c) obtained for a plurality of laser pulses transmitted to a position in the target area during a measurement period. [24] A LIDAR system (200, 500) having the following features: a transmitter (210, 510) having a laser (215, 540) and a deflector (220, 550) configured to deflect a laser beam (225) emitted by the laser (215, 540) to different positions in the target area; and the receiver (100, 235, 400, 520, 600, 700) according to one of the preceding claims. [25] A method (300) for operating a receiver (100, 235, 400, 520, 600, 700) of a system (200, 500) for light detection and distance measurement, LIDAR, the method (300) comprising the following steps: Providing (310), by each of a plurality of sensing elements (115, 565), an analog sensing signal (120a, 120b, 120c, 120d) in response to a laser pulse emitted by a transmitter (210, 510) of the LIDAR system (200, 500), each sensing element having one or more members (125a, 125b, 125c, 130a, 130b) configured to convert light (110) into an electrical signal; Providing (320), by each of a number of first conversion elements (140a, 140b, 140c, 650), a respective first digital detection signal (142a, 142b, 142c) in response to a respective first analog detection signal (120a, 120b, 120d) provided by at least one of the plurality of detection elements (115, 565), wherein the respective first conversion element (140a, 140b, 140c, 650) uses a first number of bits to represent the respective first analog detection signal (120a, 120b, 120d); Providing (330), by at least one second conversion element (150a, 150b, 675), a second digital detection signal (152a, 152b) in response to a second analog detection signal (120b, 120c) provided by at least one of the plurality of detection elements (115, 565), wherein the second conversion element (150a, 150b, 675) uses a second number of bits to represent the second analog detection signal (120b, 120c), the second number of bits being greater than the first number of bits, the number of first conversion elements (140a, 140b, 140c, 675) being greater than a number of second conversion elements (150a, 150b, 675); and Determining (340), by a processing module (160, 698), at least a first parameter (112a) of an object in a target area of ​​the LIDAR system using the first digital detection signals (142a, 142b, 142c) and a second parameter (112b) of the object using the second digital detection signal (152a, 152b).

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