Lidar chip, test system thereof and point cloud generation method

Abstract

The application discloses a laser radar chip, a test system thereof and a point cloud generation method. The laser radar chip comprises a transmitting module, a receiving module and a point cloud data processing module. The transmitting module transmits detection laser. The receiving module receives echo laser reflected by a target object. The receiving module comprises a receiving array and a time conversion unit. The receiving array comprises a plurality of receiving units. Each receiving unit comprises a plurality of receiving devices. The time conversion unit obtains a photon counting value of each receiving device at different flight times according to the flight time of the photons received by each receiving device. The point cloud data processing module is connected with the receiving module. The point cloud data processing module generates point cloud data according to the photon counting value of each receiving device at different flight times. One frame of point cloud data comprises a plurality of point cloud pixels. Each point cloud pixel corresponds to one receiving unit. Each point cloud pixel comprises a ranging distance and reflectivity of the target object. The scheme can improve the dynamic range of a single point cloud pixel.

Description

Technical Field

[0001] This application relates to the field of lidar technology, and in particular to a lidar chip and its testing system, and a point cloud generation method. Background Technology

[0002] Single-photon avalanche diode (SPAD) arrays represent the future direction of all-solid-state digital lidar. For a single SPAD, the photon detection efficiency (PDE) is typically 30%–40%, meaning that only 30%–40% of a photon hitting the SPAD is successfully recorded as a valid event, resulting in a low dynamic range for the obtained point cloud pixels. Summary of the Invention

[0003] This application provides a lidar chip and its testing system, as well as a point cloud generation method, which can improve the dynamic range of a single point cloud pixel.

[0004] In a first aspect, embodiments of this application provide a lidar chip, comprising: a transmitting module for transmitting a detection laser; a receiving module for receiving an echo laser formed by the detection laser reflected from a target object; wherein the receiving module includes a receiving array and a time conversion unit, the receiving array including multiple receiving units, each receiving unit including multiple receiving devices, the time conversion unit being used to obtain the photon count value of each receiving device at different flight times based on the flight time of the photons received by each receiving device; and a point cloud data processing module connected to the receiving module, used to generate point cloud data based on the photon count value of each receiving device at different flight times, one frame of point cloud data including multiple point cloud pixels, each point cloud pixel corresponding to a receiving unit, and each point cloud pixel including the ranging distance and reflectivity of the target object.

[0005] In one or more embodiments, the receiving device is a single-photon avalanche diode, and the lidar chip further includes: a testing module for testing the receiving array and identifying failed receiving devices in the receiving array; a first control module for controlling the shutdown of the failed receiving device; and a point cloud data processing module including: a first determining unit for determining the photon count value of the shut-down failed receiving device based on the photon count values ​​of the adjacent receiving devices of the shut-down failed receiving device, or for determining the photon count value of the shut-down failed receiving device based on the photon count values ​​of the activated receiving devices in the receiving unit corresponding to the shut-down failed receiving device; a merging unit for determining the photon count value of each receiving unit at the same flight time based on the photon count values ​​of all receiving devices in each receiving unit at the same flight time; a histogram accumulation unit for accumulating multiple photon count values ​​of each receiving unit at different flight times to obtain an accumulated histogram, wherein each emission of a probe laser yields one photon count value for each receiving unit; and a point cloud generation unit for determining the ranging distance and reflectivity corresponding to each point cloud pixel based on the accumulated histogram to generate the current frame point cloud data.

[0006] In one or more embodiments, the first determining unit is specifically used to: determine the photon count value of the closed failed receiving device based on the photon count value of the receiving devices that have successfully received photons in the left adjacent area of ​​the closed failed receiving device; or determine the photon count value of the closed failed receiving device based on the average value of the photon count values ​​of the activated receiving devices in the receiving unit corresponding to the closed failed receiving device.

[0007] In one or more embodiments, a receiving unit includes M×N receiving devices, where M is the number of rows of receiving devices, N is the number of columns of receiving devices, and M and N are both integers greater than 1; the first control module includes: a row and column control unit, which, after determining the column and row where the failed receiving device is located, controls the enable signal corresponding to the column where the failed receiving device is located and the enable signal corresponding to the row where the failed receiving device is located to be a first enable signal, so as to shut down the failed receiving device; and controls the enable signals corresponding to other columns and rows to be second enable signals, so as to start the non-failed receiving devices in the receiving unit.

[0008] Secondly, embodiments of this application provide a lidar chip testing system, including the lidar chip of the first aspect. The testing system further includes: a light source; the receiving module in the lidar chip further includes: a quenching circuit connected to the receiving array, used to quench and restore the receiving array; the testing modes in the lidar chip include: a first control unit connected to the light source, used to control the light source to emit light or stop emitting light; an observation and inspection unit connected to the first control unit and the quenching circuit, used to identify receiving devices that do not exhibit an avalanche effect as failed receiving devices in the first testing mode, and used to identify receiving devices that exhibit an avalanche effect as failed receiving devices in the second testing mode; wherein, the first control unit controls the light source to emit light as the first testing mode, and the first control unit controls the light source to stop emitting light as the second testing mode; a coordinate recording unit connected to the observation and inspection unit, used to record the position of the failed receiving device; a second control unit and a storage unit, the second control unit being connected to the coordinate recording unit, and the storage unit being connected to the second control unit, the second control unit being used to write the position of the failed receiving device to the storage unit.

[0009] Thirdly, embodiments of this application provide a point cloud generation method applied to a lidar chip as described in the first aspect. The method includes: testing a receiving array to identify failed receiving devices in the receiving array; controlling the failed receiving devices to shut down; acquiring photon count values ​​for each receiving device at different flight times; determining the photon count value of the shut-down failed receiving device based on the photon count values ​​of adjacent receiving devices, or determining the photon count value of the shut-down failed receiving device based on the photon count values ​​of activated receiving devices in the receiving unit corresponding to the shut-down failed receiving device; determining the photon count value of each receiving unit at a given flight time based on the photon count values ​​of all receiving devices in each receiving unit at the same flight time; accumulating multiple photon count values ​​of each receiving unit at different flight times to obtain an accumulated histogram, wherein each emission of a probe laser yields one photon count value for each receiving unit; and determining the ranging distance and reflectivity corresponding to each point cloud pixel based on the accumulated histogram to generate point cloud data for the current frame.

[0010] In one or more embodiments, determining the photon count value of a closed, failed receiving device based on the photon count values ​​of receiving devices adjacent to the closed, failed receiving device includes: determining the photon count value of the closed, failed receiving device based on the photon count values ​​of receiving devices that have successfully received photons in the adjacent region of the closed, failed receiving device.

[0011] In one or more embodiments, determining the photon count value of a disabled, disabled receiver based on the photon count value of a receiver activated in the receiving unit corresponding to the disabled, disabled receiver includes: determining the photon count value of the disabled, disabled receiver based on the average value of the photon count values ​​of the receiver activated in the receiving unit corresponding to the disabled, disabled receiver.

[0012] In one or more embodiments, controlling the shutdown of a failed receiving device includes: after determining the column and row where the failed receiving device is located, controlling the enable signal corresponding to the column where the failed receiving device is located and the enable signal corresponding to the row where the failed receiving device is located to be both first enable signals, so as to disable the shutdown of the failed receiving device; and controlling the enable signals corresponding to other columns or rows to be both second enable signals, so as to activate non-failed receiving devices in the receiving unit.

[0013] In one or more embodiments, testing the receiving array to determine the failed receiving devices in the receiving array includes: placing the receiving array in a strong light environment and determining the receiving devices that do not exhibit an avalanche effect as failed receiving devices; placing the receiving array in a dark environment and determining the receiving devices that exhibit an avalanche effect as failed receiving devices.

[0014] The beneficial effects of this application are as follows: The lidar chip in this embodiment includes a transmitting module, a receiving module, and a point cloud data processing module. The transmitting module is used to transmit a detection laser. The receiving module is used to receive the echo laser formed by the detection laser reflected by the target object. The receiving module includes a receiving array and a time conversion unit. The receiving array includes multiple receiving units, and each receiving unit includes multiple receiving devices. The time conversion unit is used to obtain the photon count value of each receiving device at different flight times based on the flight time of the photons received by each receiving device. The point cloud data processing module is used to generate point cloud data based on the photon count value of each receiving device at different flight times. One frame of point cloud data includes multiple point cloud pixels, each point cloud pixel corresponds to one receiving unit, and each point cloud pixel includes the ranging distance and reflectivity of the target object. Since each point cloud pixel is generated from data collected by multiple receiving devices, as long as a photon can be detected by any one of the multiple receiving devices, a valid point cloud pixel can be generated. This method can significantly improve the probability of capturing photons, thereby effectively improving the dynamic range of a single point cloud pixel. Attached Figure Description

[0015] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are not intended to limit the embodiments, and elements having the same reference numerals in the drawings are designated as similar elements.

[0016] Figure 1 This is a schematic diagram of the lidar chip provided in the embodiments of this application. Figure 1 ;

[0017] Figure 2 This is a schematic diagram of the lidar chip provided in the embodiments of this application. Figure 2 ;

[0018] Figure 3 This is a schematic diagram of the first receiving unit provided in an embodiment of this application;

[0019] Figure 4 This is a schematic diagram of the lidar chip provided in the embodiments of this application. Figure 3 ;

[0020] Figure 5 This is a schematic diagram of the lidar chip testing system provided in the embodiments of this application. Figure 4 ;

[0021] Figure 6 This is a flowchart of the point cloud generation method provided in the embodiments of this application.

[0022] Figure label:

[0023] 1000, LiDAR chip testing system; 200, Light source; 100, LiDAR chip; 40, Testing module; 41, Observation and inspection unit; 42, First control unit; 43, Coordinate recording unit; 44, Second control unit; 45, Storage unit; 30, Point cloud data processing module; 31, First determination unit; 32, Merging unit; 33, Histogram accumulation unit; 34, Point cloud generation unit; 20, Receiving module; 21, Receiving array; 22, Time conversion unit; 10, Transmitting module; T1, Target object. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0025] It should be noted that when an element is described as "connected" to another element, it can be directly connected to the other element, or there can be one or more intermediate elements between them.

[0026] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0027] Please refer to Figure 1 , Figure 1This is a schematic diagram of a lidar chip provided in an embodiment of this application. Figure 1 As shown, the lidar chip 100 includes a transmitting module 10, a receiving module 20, and a point cloud data processing module 30.

[0028] The emitting module 10 is used to emit a probe laser. In some embodiments, the emitting module 10 includes an emitting array, which includes multiple emitting devices. In some embodiments, the emitting devices are vertical-cavity surface-emitting lasers (VCSELs) or edge-emitting lasers (EELs).

[0029] The receiving module 20 is used to receive the echo laser formed by the detection laser reflected by the target object T1. The receiving module 20 includes a receiving array 21 and a time conversion unit 22. The receiving array 21 includes multiple receiving units, namely a first receiving unit A1, a second receiving unit A2, ..., a Kth receiving unit AK, where K is an integer greater than 1. Each receiving unit includes multiple receiving devices; that is, the first receiving unit A1, the second receiving unit A2, ..., the Kth receiving unit AK each include multiple receiving devices, and the number of receiving devices included in different receiving units can be the same or different. In some embodiments, the receiving device is a single-photon avalanche diode (SPAD). When a single photon is incident on the SPAD, it can trigger avalanche breakdown, thereby generating an avalanche current. The avalanche current is processed by subsequent circuitry to finally output a detectable digital pulse.

[0030] The time conversion unit 22 is used to obtain the photon count value of each receiving device at different flight times based on the flight time of the photons received by each receiving device.

[0031] The time conversion unit 22 can determine the time from the emission of the probe laser from the transmitting module 10 to the avalanche breakdown of each receiving device; this time is the photon's flight time. The flight time is pre-divided into multiple time periods. Based on the flight time of the photon received by each receiving device, the photon is assigned to the corresponding time period, and the number of photons in each time period is counted, thereby obtaining the photon count value of each receiving device in different time periods, that is, obtaining the photon count value of each receiving device under different flight times.

[0032] The point cloud data processing module 30 is connected to the receiving module 20. The point cloud data processing module 30 is used to generate point cloud data based on the photon count value of each receiving device at different flight times. One frame of point cloud data includes multiple point cloud pixels. Each point cloud pixel corresponds to a receiving unit. Each point cloud pixel includes the ranging distance and reflectivity of the target object.

[0033] In related technologies, a point cloud pixel is usually generated from data collected by a receiving device. However, for a single receiving device, its photon detection efficiency is usually 30% to 40%, that is, when a photon hits a single-photon avalanche diode, there is only a 30% to 40% probability that it will be successfully recorded as a valid event, resulting in a low dynamic range of the obtained point cloud pixel.

[0034] In the embodiments of this application, a point cloud pixel is assigned to a receiving unit. That is, a point cloud pixel is generated from data collected by a receiving unit (i.e., multiple receiving devices). Therefore, as long as a photon can be detected by any one of the multiple receiving devices, a valid point cloud pixel can be generated. This method can significantly increase the probability of capturing photons, thereby effectively improving the dynamic range of a single point cloud pixel. For example, assuming the photon detection efficiency of a single receiving device is typically 30%, and a receiving unit (corresponding to one point cloud pixel) includes four receiving devices, then the photon detection efficiency of the receiving unit is approximately 1 - (1 - 0.3). 4 ≈76% > 30%, indicating that the dynamic range of a single point cloud pixel has been significantly improved.

[0035] In some embodiments, the receiving device is a single-photon avalanche diode. Then, as... Figure 2 As shown, the lidar chip 100 also includes a test module 40 and a first control module 50.

[0036] The test module 40 is used to test the receiving array 21 to identify faulty receiving devices within it. Failed receiving devices include those in the receiving array 21 that cannot perform photoelectric conversion properly due to physical damage, manufacturing defects, aging, or environmental stress. Failed receiving devices can negatively impact the performance of the lidar chip 100, potentially leading to poor ranging accuracy.

[0037] The first control module 50 is used to control the shutdown of the failed receiving device. In some embodiments, the first control module 50 is used to cut off the power supply voltage to the failed receiving device, so that the failed receiving device stops receiving power and thus shuts down.

[0038] The point cloud data processing module 30 includes a first determining unit 31, a merging unit 32, a histogram accumulation unit 33, and a point cloud generation unit 34.

[0039] The first determining unit 31 is used to determine the photon count value of the closed failed receiving device based on the photon count value of the receiving devices adjacent to the closed failed receiving device, or to determine the photon count value of the closed failed receiving device based on the photon count value of the activated receiving device in the receiving unit corresponding to the closed failed receiving device.

[0040] Specifically, when a failed receiver is turned off, the photon count value corresponding to the failed receiver can be determined in two ways: The first way is to use the photon count value of the adjacent receiver as the photon count value corresponding to the failed receiver; the second way is to use the photon count value of the activated receiver (i.e., the non-failed receiver) in the receiving unit where the failed receiver is located to determine the photon count value corresponding to the failed receiver. For example, Figure 3 An exemplary diagram is shown, illustrating a first receiving unit A1 comprising nine receiving devices (receiving devices D1 to D9), with each receiving unit A1 corresponding to a point cloud pixel. Taking receiving device D9 as a failed receiving device, and receiving devices D1 to D8 as non-failed receiving devices as an example, the first control module 50 controls receiving device D9 to be turned off. The first determining unit 31 can use the photon count value of a receiving device adjacent to receiving device D9 (such as receiving devices D6 or D8) as the photon count value corresponding to receiving device D9; alternatively, the first determining unit 31 can use the photon count values ​​of the activated receiving devices (i.e., receiving devices D1 to D8) in the point cloud pixel where the failed receiving device is located to determine the photon count value corresponding to receiving device D9.

[0041] In some embodiments, the first determining unit 31 is specifically configured to: determine the photon count value of the closed, failed receiving device based on the photon count values ​​of the receiving devices that have successfully received photons in the adjacent region of the closed, failed receiving device; or, determine the photon count value of the closed, failed receiving device based on the average of the photon count values ​​of the activated receiving devices in the receiving unit corresponding to the closed, failed receiving device. Still using... Figure 3 Taking receiver D5 as an example, and receivers D1 to D4 and D6 to D9 as non-failed receivers, the first control module 50 controls receiver D5 to turn off. The first determining unit 31 can use the photon count values ​​of the successfully receiving photon receivers adjacent to receiver D5 (i.e., receivers D4 and D2, or receiver D4) as the photon count value corresponding to receiver D5; the first determining unit 31 can also use the average of the photon count values ​​of the receivers activated in the receiving unit where the failed receiver is located (i.e., receivers D1 to D4 and receivers D6 to D9) to determine the photon count value corresponding to receiver D9.

[0042] In practical applications, receiving arrays typically employ a row-by-row, left-to-right scan readout method. By using the photon counts of successfully receiving photons in the adjacent regions of the disabled, failed receiving device, the photon count of the disabled device can be determined. This allows for the reconstruction of the photon count using historical valid data, improving data reliability. Secondly, the locations of successfully receiving photons in adjacent regions are close to those of the disabled, failed receiving device, resulting in the highest statistical correlation and minimal substitution error. Furthermore, using the average photon count of the activated receiving devices in the corresponding receiving unit to determine the photon count helps suppress random noise, ensuring the obtained photon count is closer to the actual expected photon count, thus improving data accuracy.

[0043] When the transmitting module 10 emits a probe laser once, the merging unit 32 determines the photon count value of each receiving unit during the same flight time based on the photon count values ​​of all receiving devices in each receiving unit. Specifically, for a receiving unit (point cloud pixel), which corresponds to multiple receiving devices, if there is a failed receiving device among these multiple receiving devices, the photon count value of the failed receiving device has already been determined by the first determining unit 31, while the photon count values ​​of the non-failed receiving devices among the multiple receiving devices remain unchanged. The photon count value of the point cloud pixel is then determined by combining the photon count values ​​of the failed and non-failed receiving devices. Of course, if all the receiving devices in a receiving unit are non-failed receiving devices, the photon count value of the receiving unit is directly determined based on the photon count values ​​of the non-failed receiving devices.

[0044] The histogram accumulation unit 33 is used to accumulate multiple photon count values ​​of each receiving unit at different flight times to obtain an accumulated histogram. Each time a probe laser is emitted, a photon count value is obtained for each receiving unit. Specifically, the transmitting module 10 emits multiple probe lasers, and the histogram accumulation unit 33 superimposes the multiple photon count values ​​obtained from each emission of multiple probe lasers by the transmitting module 10 to obtain a statistically significant photon count histogram, which is the accumulated histogram.

[0045] The point cloud generation unit 34 is used to determine the ranging distance and reflectivity corresponding to each point cloud pixel based on the accumulated histogram, so as to generate point cloud data for the current frame. In some embodiments, the point cloud generation unit 34 obtains the depth value corresponding to each point cloud pixel based on the peak value of the photon counting histogram corresponding to each receiving unit. In other embodiments, the point cloud generation unit 34 can also obtain the reflectivity corresponding to each point cloud pixel based on the height and width of the photon counting histogram corresponding to each receiving unit.

[0046] In related technologies, when some receiving devices in a receiving array fail, the receiving array is usually discarded, which leads to a low yield rate for the receiving array.

[0047] In the embodiments of this application, when some receiving devices of the receiving array 21 fail, the photon count value of the failed receiving device is replaced with the photon count value of its adjacent receiving device or the photon count value of the receiving device activated in its corresponding receiving unit. At this time, not only will the point cloud quality not be affected, but the receiving array 21 can also continue to be used, which is beneficial to effectively improve the yield of the receiving array 21.

[0048] In some embodiments, a receiving unit includes M×N receiving devices, where M is the number of rows of receiving devices, N is the number of columns of receiving devices, and both M and N are integers greater than 1. Then, as follows... Figure 4 As shown, the first control module 50 includes a row and column control unit 51.

[0049] The row and column control unit 51, after determining the column and row where the failed receiving device is located, controls the enable signal corresponding to the column where the failed receiving device is located and the enable signal corresponding to the row where the failed receiving device is located to be the first enable signal, thereby turning off the failed receiving device; and controls the enable signals corresponding to other columns and rows to be the second enable signals, thereby activating the non-failed receiving devices in the receiving unit.

[0050] Still with Figure 3Taking the first receiving unit A1 as an example, the first receiving unit A1 corresponds to one point cloud pixel. The first receiving unit A1 includes 3×3 receiving devices, that is, M=N=3. The row where receiving device D1 is located is the first row R1, and the column where it is located is the first column C1; the row where receiving device D2 is located is the first row R1, and the column where it is located is the second column C2; the row where receiving device D3 is located is the first row R1, and the column where it is located is the third column C3; the row where receiving device D4 is located is the second row R2, and the column where it is located is the first column C1; the row where receiving device D5 is located is the second row R2, and the column where it is located is the second column C2; the row where receiving device D6 is located is the second row R2, and the column where it is located is the third column C3; the row where receiving device D7 is located is the third row R3, and the column where it is located is the first column C1; the row where receiving device D8 is located is the third row R3, and the column where it is located is the second column C2; the row where receiving device D9 is located is the third row R3, and the column where it is located is the third column C3.

[0051] Taking receiver D2 in the first receiving unit A1 as an example of a failed receiver, the row and column control unit 51 determines that the row where receiver D2 is located is the first row R1, and the column is the second column C2. Then, the row and column control unit 51 controls the enable signals corresponding to the first row R1 and the second column C2 to be the first enable signal EN1, and shuts down receiver D2. Simultaneously, the row and column control unit 51 controls the enable signals corresponding to all columns and rows (including the second row R2, the third row R3, the first column C1, and the third column C3) other than the first row R1 and the second column C2 to be the second enable signal EN2, and activates receivers D1, D3 through D9.

[0052] Thus, when the enable signal corresponding to any row and any column is determined to be the first enable signal E1, the receiving device located in that row and column can be identified as a failed receiving device and should be turned off, which is beneficial for accurately turning off each failed receiving device.

[0053] Please refer to Figure 5 , Figure 5 This is a schematic diagram of a lidar chip testing system provided in an embodiment of this application. Figure 5 As shown, the lidar chip testing system 1000 includes a lidar chip 100 and a light source 200 as described in any embodiment of this application.

[0054] Here, light source 200 refers to a light radiation source from the external environment of the lidar chip 100, such as sunlight.

[0055] The receiving module 20 in the lidar chip 100 also includes a quenching circuit 23. The quenching circuit 23 is connected to the receiving array 21 and is used to quench and restore the receiving array 21. Specifically, the quenching circuit 23 is used to immediately reduce the bias voltage below the breakdown voltage after the single-photon avalanche diode is triggered, terminating the avalanche process, and restoring the single-photon avalanche diode within a safe time, enabling the single-photon avalanche diode to regain its detection capability, thereby achieving repeated and reliable detection of a single photon.

[0056] The test module 40 in the lidar chip 100 includes an observation and inspection unit 41, a first control unit 42, a coordinate recording unit 43, a second control unit 44, and a storage unit 45.

[0057] The system includes a first control unit 42 connected to the light source 200, which controls the light source 200 to emit light or stop emitting light. An observation and inspection unit 41 connected to the first control unit 42 and the quenching circuit 23 is used to identify receivers that do not exhibit an avalanche effect as failed receivers in a first test mode, and to identify receivers that exhibit an avalanche effect as failed receivers in a second test mode. The first control unit 42 controls the light source 200 to emit light in the first test mode, and controls the light source 200 to stop emitting light in the second test mode. A coordinate recording unit 43 connected to the observation and inspection unit 41 records the position of the failed receiver. A second control unit 44 connected to the coordinate recording unit 43, and a storage unit 45 connected to the second control unit 44 writes the position of the failed receiver to the storage unit 45.

[0058] Specifically, the receiving array 21 is first put into operation. The first control unit 42 controls the light source 200 to emit light to execute the first test mode. At this time, the light source 200 illuminates the receiving array 21, which can be considered as the receiving array 21 being under strong light illumination. The receiving devices in the receiving array 21 are hit by photons, generating an avalanche effect. Then, the quenching circuit 23 is used to quench and restore the receiving array 21. Next, the observation and inspection unit 41 determines whether each receiving device has experienced an avalanche effect, identifies the receiving devices that have not experienced an avalanche effect, and then identifies the receiving devices that have not experienced an avalanche effect as failed receiving devices, and sends the position of the receiving devices that have not experienced an avalanche effect to the coordinate recording unit 43 for recording. The second control unit 44 is used to write the position of the failed receiving devices to the storage unit 45.

[0059] In a specific embodiment, the observation and inspection unit 41 determines whether each receiving device exhibits an avalanche effect and identifies receiving devices that do not exhibit an avalanche effect as follows: After repeatedly executing the first test mode to perform multiple tests (e.g., 3 times) on the receiving array 21, if the observation and inspection unit 41 determines that the first receiving device in the receiving array 21 has consistently not exhibited an avalanche effect, then the first receiving device is determined to be a receiving device without an avalanche effect, thus identifying the first receiving device as a failed receiving device. In this way, repeated testing eliminates randomness and improves the reliability of the determination.

[0060] Subsequently, the first control unit 42 controls the light source 200 to stop emitting light to execute the second test mode. At this time, the light source 200 stops illuminating the receiving array 21, and the receiving array 21 can be considered to be in a dark environment. The receiving devices in the receiving array 21 will not be hit by photons and produce an avalanche effect. Next, the observation and inspection unit 41 determines whether each receiving device has experienced an avalanche effect, identifies the receiving devices that have experienced an avalanche effect, determines the receiving devices that have experienced an avalanche effect as failed receiving devices, and sends the position of the receiving devices that have experienced an avalanche effect to the coordinate recording unit 43 for recording. The second control unit 44 is used to write the position of the failed receiving devices to the storage unit 45.

[0061] In a specific embodiment, the observation and inspection unit 41 determines whether each receiving device exhibits an avalanche effect, and the specific process for identifying the receiving device exhibiting an avalanche effect is as follows: After repeatedly executing the second test mode to perform multiple tests (e.g., 3 times) on the receiving array 21, if the observation and inspection unit 41 determines that the second receiving device in the receiving array 21 consistently exhibits an avalanche effect, then the second receiving device is determined to be a receiving device exhibiting an avalanche effect, and thus identified as a failed receiving device. In this way, repeated testing eliminates randomness and improves the reliability of the determination.

[0062] Please refer to Figure 6 , Figure 6 A flowchart illustrating a point cloud generation method provided in an embodiment of this application. The point cloud generation method is applied to the LiDAR chip 100 in any embodiment of this application. Figure 6 As shown, the point cloud generation method includes the following steps S610 to S670.

[0063] Step S610: Test the receiving array to identify the faulty receiving devices in the receiving array.

[0064] In some embodiments, step S610 can be implemented through the following steps: placing the receiving array in a strong light environment and identifying the receiving devices that do not exhibit an avalanche effect as failed receiving devices; placing the receiving array in a dark environment and identifying the receiving devices that exhibit an avalanche effect as failed receiving devices.

[0065] Specifically, first, the receiving array 21 is put into operation. Then, the receiving array 21 is placed in a strong light irradiation environment. The receiving devices in the receiving array 21 are hit by photons, generating an avalanche effect. Then, the quenching circuit 23 is used to quench and restore the receiving array 21. Next, it is determined whether each receiving device has experienced an avalanche effect, and the receiving devices that have not experienced an avalanche effect are identified. The receiving devices that have not experienced an avalanche effect are then identified as failed receiving devices.

[0066] Next, the receiving array 21 is placed in a dark environment so that the receiving devices in the receiving array 21 will not be hit by photons and thus will not produce an avalanche effect. Then, it is determined whether each receiving device has an avalanche effect, and the receiving devices that have an avalanche effect are identified and then identified as failed receiving devices.

[0067] Step S620: Control the failure receiver device to shut down.

[0068] In some embodiments, the faulty receiver is turned off by cutting off its power supply voltage to stop it from being powered.

[0069] In some embodiments, the specific implementation process of step S620 includes the following steps: after determining the column and row where the failed receiving device is located, controlling the enable signal corresponding to the column where the failed receiving device is located and the enable signal corresponding to the row where the failed receiving device is located to be the first enable signal, so as to turn off the failed receiving device; and controlling the enable signals corresponding to other columns or rows to be the second enable signals, so as to start the non-failed receiving devices in the receiving unit.

[0070] Thus, when it is determined that the enable signal corresponding to any row and any column is the first enable signal, the receiving device located in that row and column can be identified as a failed receiving device and should be turned off, which is beneficial for accurately turning off each failed receiving device.

[0071] Step S630: Obtain the photon count value of each receiving device at different flight times.

[0072] Specifically, the time from when the probe laser is emitted by the transmitting module 10 to when each receiving device experiences avalanche breakdown is the photon's flight time. The flight time is pre-divided into multiple time periods. Based on the flight time of the photon received by each receiving device, the photon is assigned to the corresponding time period, and the number of photons in each time period is counted. This yields the photon count value for each receiving device in different time periods, i.e., the photon count value for each receiving device under different flight times.

[0073] Step S640: Determine the photon count value of the closed failed receiver based on the photon count values ​​of the receivers adjacent to the closed failed receiver, or determine the photon count value of the closed failed receiver based on the photon count value of the receiver activated in the receiving unit corresponding to the closed failed receiver.

[0074] Specifically, when a failed receiver is turned off, the photon count value corresponding to the failed receiver can be determined in the following two ways: The first way is to use the photon count value of the receiver adjacent to it as the photon count value corresponding to the failed receiver; the second way is to use the photon count value of the receiver that is activated in the receiving unit where the failed receiver is located (i.e., the non-failed receiver) to determine the photon count value corresponding to the failed receiver.

[0075] In some embodiments, the specific implementation process of step S640 includes the following steps: determining the photon count value of the closed failed receiver based on the photon count value of the receiver that has successfully received photons in the adjacent area of ​​the closed failed receiver.

[0076] In practical applications, the receiving array 21 typically adopts a readout method that scans line by line from left to right. Based on the photon count values ​​of the receiving devices that have successfully received photons in the adjacent areas of the closed and failed receiving device, the photon count value of the closed and failed receiving device is determined. This realizes the reconstruction of the photon count value of the failed receiving device using historical valid data, which is beneficial to improving the reliability of the data. Secondly, the receiving devices that have successfully received photons in the adjacent areas are close to the closed and failed receiving devices, with the highest statistical correlation and small substitution error.

[0077] In some embodiments, the specific implementation process of step S640 includes the following steps: determining the photon count value of the closed failed receiving device based on the average value of the photon count values ​​of the activated receiving devices in the receiving unit corresponding to the closed failed receiving device.

[0078] Specifically, the average photon count of the activated receiving devices in the receiving unit corresponding to the closed failed receiving device is used to determine the photon count of the closed failed receiving device. This helps to suppress random noise and make the obtained photon count of the failed receiving device closer to the original actual photon count, thereby improving data accuracy.

[0079] Step S650: Determine the photon count value of each receiving unit during the same flight time based on the photon count values ​​of all receiving devices in each receiving unit during the same flight time.

[0080] Specifically, for a single receiving unit (point cloud pixel), it corresponds to multiple receiving devices. When a failed receiving device is present, its photon count value has already been determined in step S640, while the photon count values ​​of the non-failed receiving devices remain unchanged. The photon count value of the point cloud pixel is then determined by combining the photon count values ​​of the failed and non-failed receiving devices. Conversely, if all receiving devices in a receiving unit are non-failed, the photon count value of the receiving unit is directly determined based on the photon count values ​​of the non-failed receiving devices.

[0081] Step S660: Accumulate the multiple photon count values ​​of each receiving unit at different flight times to obtain the accumulated histogram, wherein each time a probe laser is emitted, a photon count value is obtained for each receiving unit.

[0082] Specifically, the transmitting module 10 emits multiple probe lasers. The multiple photon count values ​​obtained from each emission of multiple probe lasers by the transmitting module 10 are superimposed to obtain a statistically significant photon count histogram, which is the accumulated histogram.

[0083] Step S670: Based on the accumulated histogram, determine the ranging distance and reflectivity corresponding to each point cloud pixel to generate the current frame point cloud data.

[0084] Specifically, in some embodiments, the depth value corresponding to each point cloud pixel is obtained based on the peak value of the photon counting histogram corresponding to each receiving unit. In other embodiments, the reflectance corresponding to each point cloud pixel is obtained based on the height and width of the photon counting histogram corresponding to each receiving unit.

[0085] In related technologies, when some receiving devices in a receiving array fail, the receiving array is usually discarded, which leads to a low yield rate for the receiving array.

[0086] In the embodiments of this application, by replacing the photon count value of the failed receiving device with the expected value, not only will the point cloud quality not be affected, but the receiving array can also continue to be used, which is beneficial to effectively improve the yield of the receiving array.

[0087] This application also provides a non-volatile computer-readable storage medium storing computer-executable instructions that are executed by one or more processors, for example, executing the instructions described above. Figure 6 The method and steps.

[0088] This application also provides a computer program product, including a computing program stored on a non-volatile computer-readable storage medium. The computer program includes program instructions, which, when executed by a computer, cause the computer to perform the point cloud generation method in any of the above method embodiments, for example, to perform the above-described method. Figure 6 The method and steps.

[0089] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

[0090] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A lidar chip, characterized in that, include: The transmitting module is used to emit detection lasers; The receiving module is used to receive the echo laser formed by the detection laser reflected by the target object; The receiving module includes a receiving array and a time conversion unit. The receiving array includes multiple receiving units, and each receiving unit includes multiple receiving devices. The time conversion unit is used to obtain the photon count value of each receiving device at different flight times based on the flight time of the photons received by each receiving device. A point cloud data processing module, connected to the receiving module, is used to generate point cloud data based on the photon count values ​​of each receiving device at different flight times. One frame of point cloud data includes multiple point cloud pixels, each point cloud pixel corresponds to one receiving unit, and each point cloud pixel includes the ranging distance and reflectivity of the target object. The receiving device is a single-photon avalanche diode, and the lidar chip further includes: The testing module is used to test the receiving array and identify the failed receiving devices in the receiving array. The first control module is used to control the shutdown of the failed receiving device.

2. The lidar chip according to claim 1, characterized in that, The point cloud data processing module includes: The first determining unit is configured to determine the photon count value of the closed, failed receiving device based on the photon count value of the receiving devices adjacent to the closed, failed receiving device, or to determine the photon count value of the closed, failed receiving device based on the photon count value of the receiving device activated in the receiving unit corresponding to the closed, failed receiving device. The merging unit is used to determine the photon count value of each receiving unit during the same flight time based on the photon count values ​​of all receiving devices in each receiving unit during the same flight time. A histogram accumulation unit is used to accumulate multiple photon count values ​​of each receiving unit at different flight times to obtain an accumulated histogram, wherein each emission of the probe laser yields a photon count value for each receiving unit; and The point cloud generation unit is used to determine the ranging distance and reflectivity corresponding to each point cloud pixel based on the accumulated histogram, so as to generate the current frame point cloud data.

3. The lidar chip according to claim 2, characterized in that, The first determining unit is specifically used for: The photon count value of the closed, failed receiver is determined based on the photon count value of the receiver that has successfully received photons in the adjacent area of ​​the closed, failed receiver. or The photon count value of the shut-down, faulty receiver is determined based on the average photon count value of the receivers activated in the receiving unit corresponding to the shut-down, faulty receiver.

4. The lidar chip according to claim 2, characterized in that, One of the receiving units includes M×N receiving devices, where M is the number of rows of the receiving devices, N is the number of columns of the receiving devices, and M and N are both integers greater than 1; The first control module includes: The row and column control unit, after determining the column and row where the failed receiving device is located, controls both the enable signal corresponding to the column and the enable signal corresponding to the row where the failed receiving device is located to be the first enable signal, thereby turning off the failed receiving device; and The enable signals used to control the other columns and rows are all second enable signals, so as to activate the non-failed receiving devices in the receiving unit.

5. A lidar chip testing system, comprising the lidar chip according to any one of claims 1-4, characterized in that, The testing system also includes: light source; The receiving module in the lidar chip also includes: A quenching circuit, connected to the receiving array, is used to quench and restore the receiving array; The test modes in the lidar chip include: A first control unit is connected to the light source and is used to control the light source to emit light or stop emitting light. An observation and inspection unit, connected to the first control unit and the quenching circuit, is used to determine the receiving device that does not exhibit an avalanche effect as a failed receiving device in a first test mode, and to determine the receiving device that exhibits an avalanche effect as the failed receiving device in a second test mode. Wherein, the first control unit controls the light source to emit light in the first test mode, and the first control unit controls the light source to stop emitting light in the second test mode; A coordinate recording unit, connected to the observation and inspection unit, is used to record the position of the failed receiving device; The second control unit is connected to the coordinate recording unit, and the storage unit is connected to the second control unit. The second control unit is used to write the position of the failed receiving device to the storage unit.

6. A point cloud generation method, applied to a lidar chip as described in any one of claims 1-4, characterized in that, The method includes: The receiving array is tested to identify any faulty receiving devices within it. The failed receiving device is shut down. Obtain the photon count value of each receiving device at different flight times; The photon count value of the closed, failed receiving device is determined based on the photon count value of the receiving devices adjacent to the closed, failed receiving device; or, the photon count value of the closed, failed receiving device is determined based on the photon count value of the receiving device activated in the receiving unit corresponding to the closed, failed receiving device. The photon count value of each receiving unit at the same flight time is determined based on the photon count values ​​of all receiving devices in each receiving unit at the same flight time. The multiple photon count values ​​of each receiving unit at different flight times are accumulated to obtain an accumulated histogram, wherein each time the detection laser is emitted, a photon count value of each receiving unit is obtained; Based on the accumulated histogram, the ranging distance and reflectivity corresponding to each point cloud pixel are determined to generate the current frame point cloud data.

7. The method according to claim 6, characterized in that, Determining the photon count value of the disabled receiver based on the photon count values ​​of the receivers adjacent to the disabled receiver includes: The photon count value of the closed, failed receiver is determined based on the photon count value of the receiver that has successfully received photons in the adjacent area of ​​the closed, failed receiver.

8. The method according to claim 6, characterized in that, The step of determining the photon count value of the disabled, failed receiving device based on the photon count value of the receiving device activated in the receiving unit corresponding to the disabled, failed receiving device includes: The photon count value of the shut-down, faulty receiver is determined based on the average photon count value of the receivers activated in the receiving unit corresponding to the shut-down, faulty receiver.

9. The method according to claim 6, characterized in that, The control of shutting down the failed receiving device includes: After determining the column and row where the failed receiver is located, the enable signal corresponding to the column and the enable signal corresponding to the row where the failed receiver is located are both set to the first enable signal to disable the failed receiver; and The enable signals corresponding to other columns or rows are all configured as second enable signals to activate the non-failed receiving devices in the receiving unit.

10. The method according to claim 6, characterized in that, The step of testing the receiving array to identify faulty receiving devices in the receiving array includes: The receiving array is placed in a strong light irradiation environment, and the receiving devices that do not exhibit an avalanche effect are identified as the failed receiving devices. By placing the receiving array in a dark environment, the receiving devices that exhibit an avalanche effect are identified as the failed receiving devices.

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