Transmitting module, laser radar and related electronic equipment

Abstract

The invention discloses a transmitting module, a laser radar and related electronic equipment. The invention provides a novel laser radar detection scheme, through histogram scaling design of rough measurement and fine measurement, light flight time counting is accumulated by a histogram with low time resolution, and the position of a signal peak corresponding to an object is generally determined; and then the local histogram with high time resolution is used to accumulate the light flight time counting to improve the distance measurement precision, and the design can greatly reduce the storage area of a laser radar receiving chip on the basis of not reducing the distance measurement performance, thereby reducing the chip cost.

Description

Technical Field

[0001] This application belongs to the field of optoelectronic detection, and in particular relates to a transmitting module, lidar and related electronic equipment. Background Technology

[0002] The ranging function of lidar is typically based on the Time of Flight (ToF) measurement principle. This involves emitting a laser pulse into the measurement scene and measuring the round-trip time of the laser pulse between the lidar and the target object to calculate three-dimensional information such as the distance to the target object. Due to its advantages such as long sensing distance, high accuracy, and low power consumption, ToF measurement is widely used in consumer electronics, autonomous driving, unmanned aerial vehicles, AR / VR, and other fields.

[0003] Existing lidar typically emits multiple sensing light pulses across the field of view during sensing and performs statistical analysis on the time of the sensed light signal over the entire sensing range to determine the moment when the echo of the sensed light pulse is reflected back and received. However, for most of the flight time corresponding to the entire sensing range, lidar does not actually sense the echo of the sensed light pulse, but rather ambient light noise or other interfering light signals. To achieve sensing across the entire sensing range, existing lidar sensing methods must also perform statistical analysis on the sensing time of a large amount of ambient light noise and other interfering light signals, which requires significant memory resources and results in high product costs. Furthermore, since memory often uses MOS transistor structures, the integration density is low, the chip area is large, and this is not conducive to the miniaturization of lidar chips. Summary of the Invention

[0004] In view of this, this application provides a lidar, related electronic equipment, and a sensing method for lidar that can improve the above-mentioned problems of the prior art.

[0005] In a first aspect, this application provides a laser radar transmitting module configured to emit sensing light across a field of view, the transmitting module comprising: The light source module is configured to emit sensing light; The emitting optics are configured to emit the sensing light into corresponding zones of the field of view at different sensing periods; and The control module is configured to control the light source module and / or the emitting optics to emit sensing light into a first region of the field of view during a first sensing period and into a second region of the field of view during a second sensing period. A portion of the first region and a portion of the second region overlap each other, and the overlapping portion of the first region and the second region includes a partition, such that the lidar can perform time-of-flight sensing of the overlapping portion at different time resolutions during the first sensing period and the second sensing period, respectively.

[0006] Secondly, this application provides a lidar, comprising: The aforementioned launch module; and The receiving module includes multiple sensing pixels, each of which corresponds to a different partition in the field of view. The sensing pixels are configured to receive light signals from the corresponding partition and output corresponding light sensing signals for corresponding detection. The control module is configured to control the sensing pixels corresponding to the overlapping portion to perform one detection each in the first sensing period and the second sensing period.

[0007] Thirdly, this application provides an electronic device including the lidar described above.

[0008] The beneficial effects of this application are: Compared to existing technologies, this application proposes a novel lidar detection scheme. Through a histogram scaling design involving coarse and fine measurements, the system first accumulates the light flight time count using a histogram with lower time resolution to roughly determine the signal peak position corresponding to the object. Then, it accumulates the light flight time count using a local histogram with higher time resolution to improve ranging accuracy. This design can significantly reduce the storage area of ​​the lidar receiver chip and lower chip costs without compromising ranging performance. Attached Figure Description

[0009] The features and advantages of the present invention will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0010] Figure 1 This is a schematic diagram of the functional modules of an electronic device provided in an embodiment of this application.

[0011] Figure 2 for Figure 1 A functional module diagram of an embodiment of the lidar described herein.

[0012] Figure 3 This is a timing diagram of the signal when a lidar provided in an embodiment of this application is used for detection.

[0013] Figure 4This is a functional unit diagram of a lidar processing module provided in an embodiment of this application.

[0014] Figure 5-8 This is a schematic histogram provided for an embodiment of this application.

[0015] Figure 9 This is a schematic diagram of the structure of a transmitting module provided in an embodiment of this application.

[0016] Figure 10 This is a schematic diagram of the field of view scanning of a lidar provided in an embodiment of this application.

[0017] Figure 11 This is a schematic diagram of the structure of a lidar as an automotive lidar provided in one embodiment of this application. Detailed Implementation

[0018] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. In the description of this application, it should be understood that the terms "first" and "second" are used for description only and should not be construed as indicating or implying relative importance or implicitly specifying the number or order of the indicated technical features. Thus, technical features defined with "first" and "second" may explicitly or implicitly include one or more of the stated technical features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0019] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integrated connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0020] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, only specific examples of components and settings are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or reference letters may be repeated in different examples; such repetition is for the purpose of simplifying and clearly describing this application and does not in itself indicate a specific relationship between the various embodiments and / or settings discussed. Moreover, the various specific processes and materials described below are merely examples for implementing the technical solutions of this application; however, those skilled in the art should recognize that the technical solutions of this application can also be implemented using other processes and / or other materials not described below.

[0021] Furthermore, the described features and structures can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced even without one or more of the specific details described, or with other structures, components, etc. In other instances, well-known structures or operations are not shown or described in detail to avoid obscuring the focus of this application.

[0022] An embodiment of this application provides a laser radar transmitting module configured to emit sensing light across a field of view, the transmitting module comprising: The light source module is configured to emit sensing light; The emitting optics are configured to emit the sensing light into corresponding zones of the field of view at different sensing periods; and The control module is configured to control the light source module and / or the emitting optics to emit sensing light into a first region of the field of view during a first sensing period and into a second region of the field of view during a second sensing period. A portion of the first region and a portion of the second region overlap each other, and the overlapping portion of the first region and the second region includes a partition, such that the lidar can perform time-of-flight sensing of the overlapping portion at different time resolutions during the first sensing period and the second sensing period, respectively.

[0023] In some embodiments, the light source module includes multiple light sources, the emitting optics includes a lens, and the control module emits sensing light to different areas of the field of view by illuminating light sources at different locations in a time-division manner.

[0024] In some embodiments, the emitting optics includes at least one light deflection device, and the control module controls the deflection angle of the passing light beam by the light deflection device to deflect the sensing light to different regions of the field of view in a time-division manner.

[0025] In some embodiments, the at least one optical deflection device is selected from one or more combinations of acousto-optic deflectors, liquid crystal polarization gratings, electro-optic polarizers, and liquid crystal optical phased arrays.

[0026] In some embodiments, the light source module includes multiple light sources, and the control module is further configured to control the sensing light emitted by one of the light sources to be emitted by the emitting optics to a corresponding partition within the field of view during a sensing period.

[0027] In some embodiments, the control module is further configured to control a corresponding light source to emit multiple sensing light pulses according to a preset time sequence within a sensing period. The sensing period includes multiple pulse periods corresponding to the multiple sensing light pulses respectively. The control module is configured to control a light source to emit a sensing light pulse corresponding to a pulse period.

[0028] In some embodiments, the control module is further configured to control at least two light sources emitting light during the same sensing period to emit sensing light pulses at different times during a pulse period.

[0029] In some embodiments, the sensing light pulses emitted by the at least two light sources during the same sensing period are respectively emitted to different sections of the field of view.

[0030] In some embodiments, the control module is further configured to control the at least two light sources to have a time difference between the times when they emit sensing light pulses within a pulse period, wherein the time difference formed by the at least two light sources in different pulse periods varies randomly.

[0031] In some embodiments, the control module is further configured to control the multiple light sources emitting light in the same sensing period to emit sensing light pulses at times corresponding to each other in a pulse period, wherein the time differences formed by the multiple light sources in different pulse periods vary randomly.

[0032] In some embodiments, the pulse period includes a preset duration of light emission timing adjustment interval. The timing at which different light sources emit sensing light pulses within the same sensing period is randomly set within the light emission timing adjustment interval. The random variation range of the time difference is greater than or equal to zero and less than or equal to the preset duration of the light emission timing adjustment interval.

[0033] In some embodiments, the control module is further configured to control the area illuminated by the light source module and / or the emitting optics within the same sensing period to include two partitions, with other partitions spaced between the two partitions.

[0034] One embodiment of this application provides a lidar, including: The aforementioned launch module; and The receiving module includes multiple sensing pixels, each of which corresponds to a different partition in the field of view. The sensing pixels are configured to receive light signals from the corresponding partition and output corresponding light sensing signals for corresponding detection. The control module is configured to control the sensing pixels corresponding to the overlapping portion to perform one detection each in the first sensing period and the second sensing period.

[0035] In some embodiments, the receiving module further includes a processing module configured to perform statistical analysis on the time of the pixel output light sensing signal according to a preset time resolution; the control module is further configured to control the processing module to perform statistical analysis on the time of the sensor pixel corresponding to the overlapping part output light sensing signal at a first time resolution during a first sensing period, and to perform statistical analysis on the time of the sensor pixel corresponding to the overlapping part output light sensing signal at a second time resolution during a second sensing period; wherein the second time resolution is higher than the first time resolution.

[0036] In some embodiments, the processing module is further configured to generate a first histogram based on statistical analysis of the time of light signal output by the sensing pixel during a first sensing period, wherein the time range covered by the first histogram is divided into multiple time bins at a first time resolution; the control module is further configured to determine at least one time bin with a peak or near a peak in the first histogram as a target time bin, and control the processing module to perform statistical analysis only on the time when the sensing pixel outputs light sensing signal within the target time bin at a second time resolution during a second sensing period to generate a second histogram, and to perform corresponding detection based on the second histogram.

[0037] In some embodiments, a time bin in the first histogram has a time segment that partially overlaps with the time segments of two adjacent time bins before and after it. If the output time of the photosensitive signal is within the overlapping time segment, the processing module is configured to add a count corresponding to the photosensitive signal in each of the two time bins that include the overlapping time segment.

[0038] In some embodiments, the pulse width of the sensing light pulse is equal to the duration of a time bin in the first histogram, or the difference between the pulse width and the duration of a time bin in the first histogram is less than a preset threshold.

[0039] Embodiments of this application also provide an electronic device including the aforementioned lidar. The electronic device performs corresponding functions based on information detected by the lidar. Examples of such electronic devices include: mobile phones, automobiles, robots, access control / monitoring systems, smart locks, unmanned vehicles, and drones. The information detected by the lidar includes, for example, proximity information, depth information, distance information, coordinate information, and reflectivity information of objects within the field of view. The three-dimensional information such as depth, distance, and coordinates can be used for functions such as 3D modeling, identity recognition, autonomous driving, machine vision, monitoring, drone control, augmented reality (AR) / virtual reality (VR), simultaneous localization and mapping (SLAM), and object proximity detection. The reflectivity information can be used to assist in determining the type of object within the field of view and to assist in adjusting the operating parameters of the lidar to improve detection performance.

[0040] The aforementioned lidar can be applied in fields such as autonomous vehicles, autonomous aircraft, 3D printing, VR, AR, low-speed unmanned vehicles, and service robots. Taking autonomous vehicles as an example, lidar installed in an autonomous vehicle can scan the surrounding environment by rapidly and repeatedly emitting laser beams. By calculating the time delay (i.e., flight time) between the emission time of the laser beam and the return time of the echo beam, the 3D / reflectivity information of each object is determined, thereby obtaining point cloud data reflecting the shape, position, and movement of one or more objects in the surrounding environment. Simultaneously, lidar can also determine the angular information describing the orientation of the laser beam's field of view. Combining the 3D / reflectivity information of each object with the angular information of the laser beam generates a point cloud map including all objects in the scanned surrounding environment. This point cloud map can be used to guide the intelligent driving of machinery and equipment.

[0041] The following will describe in detail, with reference to the accompanying drawings, embodiments of lidar applied to electronic devices.

[0042] Figure 1 This is a schematic diagram of the functional modules of a lidar applied to an electronic device according to an embodiment of this application. Figure 2 This is a schematic diagram of the functional modules of the lidar provided in the embodiments of this application.

[0043] Reference Figure 1 and Figure 2The electronic device 1 includes a lidar 10. The lidar 10 can detect objects 2 within its field of view to obtain corresponding information. The field of view can be defined as the three-dimensional spatial range within which the lidar 10 can effectively detect objects, and can also be referred to as the field of view angle of the lidar 10. The acquired information includes, but is not limited to, one or more of the following: proximity information of the object 2, depth information of the surface of the object 2, distance information of the object 2, spatial coordinate information of the object 2, and reflectivity information of the object 2.

[0044] The electronic device 1 may include an application module 20, which is configured to perform preset operations or implement corresponding functions based on the detection results of the lidar 10. For example, but not limited to: determining whether an object 2 is present within a preset field of view in front of the electronic device 1 based on its proximity information; or controlling the movement of the electronic device 1 to avoid obstacles based on the distance information of the object 2; or realizing 3D modeling, identity recognition, machine vision, etc., based on the depth information of the object 2's surface. That is, the application module 20 may be a collection of hardware required to perform the above operations and implement the above functions, and software required to control and coordinate the operation of the hardware.

[0045] The electronic device 1 may further include a storage medium 30, which can support the storage needs of the electronic device 1 and / or the lidar 10 during operation. Figure 1 As shown, in some embodiments, the storage medium 30 may be disposed inside the electronic device 1. For example... Figure 2 As shown, in some embodiments, the storage medium 30 may also be disposed inside the lidar 10.

[0046] The electronic device 1 may further include a processor 40, which can support the data processing needs of the electronic device 1 and / or the lidar 10 during operation. Figure 1 As shown, in some embodiments, the processor 40 may be located inside the electronic device 1. For example... Figure 2 As shown, in some embodiments, the processor 40 may also be located inside the lidar 10.

[0047] Optionally, in some embodiments, the lidar 10 may be, for example, a dToF measurement device for three-dimensional information sensing based on the direct time of flight (dToF) principle. The dToF measurement device can emit sensing light within its field of view and receive sensing light reflected back from the object 2 within that field of view. The time difference between the emission and reception times of the reflected sensing light is called the flight time t of the sensing light. The three-dimensional information of the object 2 can be obtained by calculating half the distance traveled by the sensing light within the flight time t. Where c is the speed of light.

[0048] In other embodiments, the lidar 10 may also be an iToF measurement device that uses the indirect time-of-flight (iToF) measurement principle to sense three-dimensional information. The iToF measurement device obtains the three-dimensional information of the object 2 by comparing the phase difference between the emitted and reflected light.

[0049] In the embodiments described below, the lidar 10 is mainly used as a dToF measurement device for illustration.

[0050] In some embodiments, such as Figure 2 As shown, the lidar 10 includes a transmitting module 12, a receiving module 14, a processing module 15, and a control module 18. The transmitting module 12 is configured to emit sensing light into the field of view to detect objects 2 within that field of view. A portion of the sensing light is reflected back by the object 2, and the reflected light echo carries three-dimensional information about the object 2. A portion of this reflected light echo can be sensed by the receiving module 14 to obtain relevant information about the object 2. The receiving module 14 is configured to sense light signals from the field of view and output corresponding light sensing signals. For example, the light signals sensed by the receiving module 14 can be photons, including photons from the reflected light echo from the object 2 within the field of view and photons from ambient light within the field of view. The processing module 15 is configured to statistically analyze the generation time of the photosensitive signal to obtain the moment when the sensing light echo is sensed by the receiving module 14, obtain the three-dimensional information of the object 2 based on the time difference between the emission time of the sensing light and the time when it is reflected back and sensed, and / or obtain the reflectivity information of the object 2 based on the photosensitive signal count value triggered by the sensing light echo.

[0051] The processing module 15 may be located on the lidar 10. It should be understood that, in some other embodiments, all or part of the functional units of the processing module 15 may also be located on the electronic device 1.

[0052] In some embodiments, the transmitting module 12 is configured to emit laser pulses as sensing light according to a preset time sequence. Specifically, the control module 18 controls the transmitting module 12 to emit sensing light pulses to different areas within the field of view in a time-division manner according to a preset scanning method for detection. Multiple sensing light pulses are emitted to each area according to a corresponding preset time sequence. The processing module 15 analyzes the time distribution of the light signal sensed by the receiving module 14 and the output light sensing signal during the multiple sensing light pulses emitted to one area to obtain the corresponding information for that area. This process can be considered as one area detection period. Scanning multiple areas within the field of view one by one is considered as completing one frame detection of the entire field of view, thus obtaining the corresponding information for all areas within the entire field of view, which can be used to construct a point cloud of one frame for the entire field of view. That is, one frame detection of the field of view includes multiple area detection periods corresponding to area scanning.

[0053] Optionally, the sensing light is, for example, visible light, infrared light or near-infrared light, with a wavelength range of, for example, 390 nm-780 nm, 700 nm-1400 nm, 800 nm-1000 nm, 900 nm-1600 nm, etc.

[0054] like Figure 2 As shown, the emitting module 12 includes a light source module 122 and an emitting optics 13. The light source module 122 is configured to emit sensing light, and the emitting optics 13 is configured to emit the sensing light to a corresponding partition within the field of view. The control module 18 is configured to control the light source module 122 and / or the emitting optics 13 to emit the sensing light to the corresponding partition within the field of view in a time-division manner according to a preset scanning method. In some embodiments, the emitting optics 13 includes a lens or a lens group consisting of one or more lenses, and the position of the sensing light emitted to the partition within the field of view can be controlled by selecting the position of the sensing light emitted from the light source module 122. In some embodiments, the emitting optics 13 includes a semi-solid-state rotating mirror and / or a MEMS galvanometer, and the position of reflecting the sensing light to the corresponding partition within the field of view can be controlled by adjusting the rotation angle of the rotating mirror and / or the vibration angle of the MEMS galvanometer. In some embodiments, the emitting optical device 13 includes a light deflector, such as an acousto-optic deflector, a liquid crystal polarization grating, an electro-optic polarizer, and a liquid crystal optical phased array, and the light deflector can be adjusted to deflect the sensing light to the position of the corresponding partition within the field of view by adjusting the deflection angle of the light beam.

[0055] The light source module 122 includes one or more light sources (not shown), which are configured to emit sensing light. The light source can be, for example, a vertical-cavity surface-emitting laser (VCSEL), an edge-emitting laser (EEL), a light-emitting diode (LED), a laser diode (LD), or a fiber laser. The edge-emitting laser can be a Fabry-Perot (FP) laser, a distributed feedback (DFB) laser, an electro-absorption modulated (EML) laser, etc., and this embodiment does not limit the specific type of laser used.

[0056] like Figure 2 As shown, the receiving module 14 may include a photoelectric sensor 140 and a receiving optics 22. The photoelectric sensor 140 includes at least one sensing pixel 220. The field of view of the lidar includes multiple zones located in different orientations. The receiving optics 22 is disposed on the light-incident side of the photoelectric sensor 140 and is configured to transmit light signals from each zone in the field of view to the corresponding sensing pixel 220 on the photoelectric sensor 140 for sensing. That is, the sensing pixel 220 of the photoelectric sensor 140 has a preset correspondence with multiple zones in the field of view, and the zone corresponding to the sensing pixel 220 can be regarded as a part of the field of view covered by the receiving field of view angle formed by the sensing pixel 220 through the receiving optics 22. Thus, if there is an object 2 in the zone scanned by the sensing light, the sensing light echo reflected back by the object 2 will be transmitted to the corresponding sensing pixel 142 through the receiving optics 22 and sensed.

[0057] In some embodiments, the receiving optics 22 includes a lens or a lens group consisting of one or more lenses, configured to transmit light signals from different zones of the field of view to corresponding different sensing pixels 220 for sensing. In this case, multiple zones within the field of view are configured to correspond one-to-one with multiple sensing pixels 220. In some embodiments, the receiving optics 22 includes a semi-solid-state rotating mirror and / or a MEMS galvanometer, which can adjust the rotation angle of the rotating mirror and / or the vibration angle of the MEMS galvanometer to reflect light signals from different zones to the corresponding sensing pixels 220 in a time-division manner. In this case, multiple different zones within the field of view are configured to correspond to the same sensing pixel in a time-division manner. In some embodiments, the receiving optics 22 includes a light deflector, such as an acousto-optic deflector, a liquid crystal polarization grating, an electro-optic polarizer, and a liquid crystal optical phased array, which can adjust the deflection angle of the light beam by the light deflector to reflect light signals from different zones to the corresponding sensing pixels in a time-division manner. In this case, multiple different zones within the field of view are configured to correspond to the same sensing pixel in a time-division manner.

[0058] In some embodiments, such as Figure 2 As shown, the emitting optical path of the emitting module 12 and the receiving optical path of the receiving module 14 are side-by-side off-axis optical paths. The light-emitting surface of the emitting module 12 and the light-incident surface of the receiving module 14 both face the same side of the lidar 10. The distance between the emitting module 12 and the receiving module 14, also known as the baseline length, can range from, for example, 2 millimeters (mm) to 20 mm. Since the emitting module 12 and the receiving module 14 are relatively close, although the emission path of the sensing light from the emitting module 12 to the object 2 and the return path after reflection from the object 2 to the receiving module 14 are not exactly equal, both are much larger than the distance between the emitting module 12 and the receiving module 14, and can be considered approximately equal. Therefore, the distance between the object 2 and the lidar 10 can be calculated by multiplying half the flight time t of the reflected sensing light echo from emission to reflection and sensing by the speed of light c. In some other embodiments, the transmitting module 12 and the receiving module 14 may also form a coaxial receiving and transmitting path through a beam splitter (not shown).

[0059] A sensing pixel 142 may include a single photoelectric conversion device or multiple photoelectric conversion devices. The photoelectric conversion device is configured to sense the received light signal and convert it into a corresponding electrical signal as the photosensitized signal output. In some embodiments, the photoelectric conversion device is, for example, a single photon avalanche diode (SPAD). When a working voltage exceeding the reverse breakdown voltage is applied across the SPAD, it is in a Geiger state. At this time, a single photon entering the SPAD has a certain probability of triggering an avalanche effect, outputting a multiplied avalanche electrical signal as the photosensitized signal, thus making it susceptible to ambient light noise. To improve the signal-to-noise ratio, for lidar using SPADs as photoelectric conversion devices, time-correlated single photon counting (TCSPC) is required. This involves statistically analyzing the timing of the SPAD's output photosensitized signal by emitting multiple sensing light pulses to complete the detection of a region. Thus, as... Figure 3 As shown, each partition detection period includes multiple pulse periods corresponding to multiple sensing light pulses. A pulse period can be defined as the time interval between the emission time of one sensing light pulse and the emission time of the next sensing light pulse, which at least covers the flight time required for the sensing light pulse to travel to and from the maximum detection distance of the lidar.

[0060] In some embodiments, such as Figure 4 As shown, the processing module 15 may include functional units such as a counting unit 152, a statistics unit 154, a peak finding unit 156, and an information acquisition unit 158.

[0061] The counting unit 152 is configured to determine the time when the sensing pixel 142 of the receiving module 14 senses a light signal and outputs a corresponding light sensing signal, and counts in the corresponding time bin. During the detection process, the lidar 10 emits multiple sensing light pulses through the transmitting module 12. The counting unit 152 starts timing each time the transmitting module 12 emits a sensing light pulse to record the time when the sensing pixel 142 of the receiving module 14 senses a light signal and outputs a corresponding light sensing signal within the pulse period corresponding to that sensing light pulse. During this period, each time the sensing pixel 142 of the receiving module 14 senses a light signal and outputs a corresponding light sensing signal, the counting unit 152 counts in the corresponding time bin according to the time of the output light sensing signal, forming a corresponding light signal count. In some embodiments, the counting unit 152 implements the timing function, for example, through a time-to-digital converter (TDC) 1522. The TDC 1522 is connected to the corresponding sensing pixel 142 on the receiving module 14 and is configured to record the time of sensing a light signal based on the light sensing signal generated by the corresponding sensing pixel 142. For example, the TDC1522 is synchronously triggered to start timing each time a sensing light pulse is emitted. The timing stops upon subsequent response to the light-sensing signal generated by the corresponding sensing pixel 142, and the duration of the timing is taken as the generation time of the light-sensing signal, which is also the sensing time of the corresponding light signal that triggered the light-sensing signal. In this case, the time resolution of the TDC1522 is the highest time resolution for the counting unit 152 to record the generation time of the light-sensing signal. The counting unit 152 also includes a counting memory, which is allocated one counting storage unit for each time slot. Each time the TDC1522 records the sensing time of a light signal, it increments the count in the corresponding time slot's counting storage unit by one; that is, the light signal count in the corresponding time slot increases by one. The light signal count value of each time slot is the cumulative number of times the light signal was sensed during multiple pulse periods at the time represented by that time slot. Therefore, the time bins, which are the time units Δt used by the counting unit 152 to record the time of the light-sensing signal generation, reflect the accuracy of the counting unit 152 in recording the light signal sensing time. The finer the time bins, the higher the accuracy of the time recording, meaning the higher the time resolution of the counting unit 152. Figure 3 As shown, a pulse period is divided into N time bins according to a preset time resolution, so that the receiving module 14 can accumulate and count the light signals sensed in multiple pulse periods at a preset time resolution.

[0062] The statistical unit 154 is configured to count the cumulative optical signals within each time slot to obtain a statistical histogram reflecting the time distribution of the number of optical signals sensed by the receiving module 14 over multiple pulse periods within a zone detection period. Please refer to [further details omitted]. Figure 5 The horizontal axis of the statistical histogram represents the timestamp of each corresponding time bin, and the vertical axis represents the cumulative optical signal count value within each corresponding time bin. In some embodiments, the statistical unit 154 may include a histogram circuit 1544 (see...). Figure 4 The histogram circuit 1544 is configured to perform statistical analysis on the optical signal counts within each time bin to generate a histogram. It should be understood that the statistical unit 154 performs statistical analysis on the cumulative optical signal counts corresponding to multiple pulse periods within a single detection period. To ensure the counts have mathematical statistical significance, the number of sensing light pulses emitted within a single detection period can be as high as hundreds, thousands, tens of thousands, hundreds of thousands, or even millions.

[0063] During the sensing process, a large number of ambient light photons are also sensed by the receiving module 14, generating corresponding optical signal counts. The probability of these ambient light photons being sensed and leaving a count in each time bin tends to be the same, constituting the noise level of the field of view. In scenes with strong ambient light, the average level of the noise level is relatively high; in scenes with weak ambient light, the average level of the noise level is relatively low. Based on this, the optical signal count generated by the sensed light echo reflected from object 2 is superimposed on the noise level, making the optical signal count in the time bin corresponding to the moment the sensed light echo is sensed significantly higher than the optical signal count in other time bins, thus forming a prominent signal peak. The height of the signal peak is affected by factors such as the optical power of the sensed light pulse, the reflectivity of object 2, and the field of view of the lidar 10. The width of the signal peak is affected by factors such as the pulse width of the emitted sensed light pulse, the photoelectric conversion element of the receiving module 14, and the timing jitter of the TDC1522. Therefore, the peak finding unit 156 is configured to find the time bin corresponding to the peak value of the signal peak in the histogram. The information acquisition unit 158 ​​is configured to obtain the flight time of the related sensing light echo reflected back by the object 2 based on the time difference between the timestamp t1 of the peak time bin and the emission time t0 of the related sensing light pulse that generated the signal peak, and calculate the distance information between the object 2 reflecting the sensing light and the lidar 10 accordingly. In some embodiments, the information acquisition unit 158 ​​is further configured to obtain the reflectivity of the object 2 based on the analysis of the optical signal count value of the peak time bin, the emission power of the sensing light pulse, and / or the distance information of the object 2.

[0064] In some embodiments, the receiving module 14 may further include peripheral circuitry (not shown) consisting of one or more devices such as a signal amplifier and an analog-to-digital converter (ADC), which may be partially or wholly integrated into the photoelectric sensor 140. The light-sensing signal generated by the sensing pixel 220 is shaped and preliminarily processed by the aforementioned peripheral circuitry before being output to the processing module 23 for processing and analysis.

[0065] To accurately determine the distance to objects within the field of view of a lidar within its maximum detection range, the counting unit typically divides the flight time range corresponding to the maximum detection range into time bins based on the highest time resolution of the time-of-flight (TDC). However, this approach results in a large number of time bins. Since each time bin requires a corresponding counting storage unit, dividing the time bins based on the highest TDC resolution necessitates a significant number of counting storage units, leading to high chip costs. Furthermore, the counting storage units require numerous MOSFETs, resulting in low integration and a large chip area, which hinders chip miniaturization.

[0066] To address this, embodiments of this application propose a lidar configured to sense a preset field of view. The lidar includes a transmitting module, a receiving module, a processing module, and a control module. The transmitting module is configured to emit multiple sensing light pulses into the preset field of view according to a preset time sequence. The receiving module includes at least one sensing pixel, configured to respond to light signals from the field of view and output corresponding light-sensing signals. The processing module is configured to statistically analyze the time of the sensing pixel's output light-sensing signals according to a preset time resolution. The control module is configured to, for the same partition within the field of view, first statistically analyze the time of the sensing pixel's output of light-sensing signals related to that partition at a first time resolution to generate a first histogram, determine at least one time bin with or near the peak value in the first histogram as a target time bin, and then statistically analyze only the time of the sensing pixel's output of light-sensing signals related to that partition within the target time bin at a second time resolution to generate a second histogram, and perform corresponding detection based on the second histogram. The second time resolution is higher than the first time resolution.

[0067] Specifically, if the maximum detection distance of the lidar is 300m, and the time resolution of the time control (TDC) is 1ns, the corresponding distance detection resolution is 15cm. Therefore, dividing the time range corresponding to the maximum detection distance using the TDC's time resolution requires 2000 time bins. Thus, in situations such as... Figure 6In the illustrated embodiment, the control module can control the processing module to divide the flight time range corresponding to the maximum detection distance into time bins with a lower first time resolution. For example, the time interval corresponding to each time bin is 2 ns. This reduces the required number of time bins by half, and the corresponding number of counting storage units is also halved. In this case, the control module controls the counting and statistical units of the processing module to first perform statistical analysis on the light signal sensing time of the sensing pixels based on the time bins divided at the first time resolution to generate a first histogram. The control module controls the peak-finding unit of the processing module to determine the time bin corresponding to the peak value in the first histogram, and takes at least one time bin near the peak value as the target time bin, for example: Figure 6 The peak of the first histogram is located in time bin number 9, corresponding to an optical signal sensing time range of 17ns-18ns. This means the optical signal count corresponding to the sensed light echo is highly likely within this 17ns-18ns sensing time range. Furthermore, since the actual peak may span two adjacent time bins in the first histogram, to avoid losing the optical signal count of the actual peak, multiple time bins near the peak in the first histogram can be used as target time bins, for example... Figure 6 The 8th and 10th time bins before and after the 9th time bin are also used as target time bins for detailed measurement. The control module controls the processing module to divide the target time bins into time bins with a higher second time resolution. For example, using the TDC time resolution of 1ns as the second time resolution, the 8th-10th target time bins are further subdivided into 6 time bins, corresponding to the 15th-20th time bins divided with the second time resolution within the time range corresponding to the maximum detection distance. The control module controls the processing module to perform statistical analysis on the optical signal sensing time within the target time bins after fine division with the second time resolution to generate a second histogram. The peak value in the second histogram is the 18th time bin. Since the time resolution of the second histogram is consistent with the highest TDC time resolution of 1ns, the achievable distance detection resolution is 15cm, so the corresponding detection based on the second histogram has good accuracy. And since the number of time bins required for the first histogram is halved, the first histogram and the second histogram... Figure 1 The total number of time bins required is less than that required for statistical analysis of the optical signal count across the entire time range corresponding to the maximum detection distance using the highest TDC time resolution, thus saving counting storage space while maintaining high sensing accuracy.

[0068] In some embodiments, further, the pulse width of the sensing light pulse is equal to the duration of a time bin in the first histogram, or the difference between the pulse width and the duration of a time bin in the first histogram is less than a preset threshold. Although a lower first temporal resolution corresponds to fewer time bins in the first histogram, resulting in more saved counting storage space, however, as... Figure 7 As shown, when the time bins in the first histogram are too wide, the counts of ambient light photons are continuously merged into the same time bin, while the count of the sensed light echo does not increase with the widening of the time bins. The count differences between different time bins tend to be similar, and the peak values ​​become less and less obvious, reducing the signal-to-noise ratio of the first histogram. Therefore, when the time resolution in the first histogram, i.e., the duration of the time bin, is equal to or close to the pulse width of the sensed light pulse emitted by the transmitting module, the probability of the sensed light echo being counted in the same time bin is the highest, and the signal-to-noise ratio is better at this time.

[0069] In some embodiments, further, when the actual peak value of the signal peak spans two time bins in the first histogram, the actual peak count may be distributed across the two time bins, causing the count in either time bin to fail to meet the signal-to-noise ratio requirement, thus making it impossible to locate the peak position of the signal peak. For example... Figure 8 As shown, the time bin width of the coarse histogram is four times the width of the time bins defined by the TDC time resolution. When accumulating the coarse histogram A normally from time 0, the peak values ​​(time bins 15 and 16 of the fine histogram) cross time bins 3 and 4 of the coarse histogram A. This scattered counting results in time bins 3 and 4 not standing out against the background noise, leading to a weak signal-to-noise ratio. Therefore, a half-phase coarse histogram is added to the existing coarse histogram to address the issue of signal peaks crossing bin boundaries. Taking a time resolution of 4ns as an example, the coarse histogram typically starts from time 0, with 0-4ns as time bin 1, 4-8ns as time bin 2, 8-12ns as time bin 3, and so on. In this embodiment, the time bins of the coarse histogram are doubled: 0-4ns is time bin number 1, 2-6ns is time bin number 2, 4-8ns is time bin number 3, 6-10ns is time bin number 4, 8-12ns is time bin number 5, and so on, until there is a time bin that can perfectly cover the actual peak value of the signal. Figure 8As shown in coarse histogram B, the peak value of the signal is located exactly in the 3.5th time bin of the half-phase histogram, and its count is significantly higher than the background noise. That is, the time segment corresponding to one of the time bins partially overlaps with the time segments corresponding to the two adjacent time bins before and after it. If the output time of a photosensitive signal is located within the overlapping time segments, the processing module is configured to add a count corresponding to the photosensitive signal in each of the two time bins including the overlapping time segments.

[0070] In some embodiments, the emitting optics includes a lens, and the control module emits sensing light to different regions of the field of view by illuminating light sources at different locations in a time-division manner. In some embodiments, such as Figure 9 As shown, the emitting optics 13 includes at least one light deflector 130, and the control module 18 controls the deflection angle of the light beam by the light deflector 130 to deflect the sensing light to different regions of the field of view in a time-division manner. Figure 10 As shown, the control module 18 is configured to control the light source module and / or the emitting optics to emit sensing light into a first region of the field of view during a first sensing period and into a second region of the field of view during a second sensing period. A portion of the first region and a portion of the second region overlap, and the overlapping portion includes a partition, enabling the lidar to perform time-of-flight sensing of the overlapping portion at different time resolutions during the first and second sensing periods, respectively. For example, time-of-flight sensing of the overlapping portion is performed at a lower first time resolution during the first sensing period and at a higher second time resolution during the second sensing period, thereby reducing the time lost in coarse and fine measurement by increasing parallelism.

[0071] In some embodiments, all or part of the functional units in the control module 18 and / or processing module 15 may include firmware embedded in the storage medium 30 or computer software code stored in the storage medium 30, and be executed by one or more corresponding processors 40 to control related components to achieve corresponding functions. The processor 40 may be, for example, but not limited to, an application processor (AP), a central processing unit (CPU), a microcontroller (MCU), etc. The storage medium 30 may include, but is not limited to, flash memory, electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), hard disk, etc.

[0072] In some embodiments, the processor 40 and / or storage medium 30 may be disposed within the lidar 10, for example, integrated on the same circuit board as the transmitting module 12 or the receiving module 14. Optionally, in other embodiments, the processor 40 and / or storage medium 30 may also be disposed in other locations on the electronic device 1, such as on the main circuit board of the electronic device 1.

[0073] In some embodiments, some or all of the functional units of the control module 18 and / or processing module 15 may also include hardware, for example, implemented by any one or a combination of the following techniques: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), object-specific drive circuits, etc.

[0074] It is understood that some different functional units of the control module 18 and / or processing module 15 may each include the same hardware. For example, the acoustic-optical deflection control unit 184 and the emission energy adjustment unit 189 may both include the drive circuit of the acoustic wave generator 1242.

[0075] It is understood that the hardware used to implement the functions of the control module 18 and / or processing module 15 can be located within the lidar 10. Alternatively, the hardware used to implement the functions of the control module 18 and / or processing module 15 can also be located in other locations on the electronic device 1, such as on the main circuit board of the electronic device 1.

[0076] like Figure 11 As shown, in some embodiments, the lidar 10 is, for example, a lidar radar, and the electronic device 1 is, for example, a car. The lidar can be installed in multiple different locations on the car to detect the distance information of objects within the car's surrounding area and thereby achieve driving control.

[0077] It should be noted that the technical solution to be protected by this application may satisfy only one of the above embodiments or simultaneously satisfy multiple of the above embodiments. In other words, embodiments composed of one or more of the above embodiments also fall within the protection scope of this application.

[0078] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with the said embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0079] It should be understood that various parts of the embodiments of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple functional units can be implemented using software or firmware stored in a storage medium and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0080] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A laser radar transmitting module, characterized in that, The emitting module is configured to emit sensing light across a field of view, and includes: The light source module is configured to emit sensing light; The emitting optics are configured to emit the sensing light into corresponding zones of the field of view at different sensing periods; and The control module is configured to control the light source module and / or the emitting optics to emit sensing light into a first region of the field of view during a first sensing period and into a second region of the field of view during a second sensing period. A portion of the first region and a portion of the second region overlap each other, and the overlapping portion of the first region and the second region includes a partition, such that the lidar can perform time-of-flight sensing of the overlapping portion at different time resolutions during the first sensing period and the second sensing period, respectively.

2. The transmitting module as described in claim 1, characterized in that, The light source module includes multiple light sources, the emitting optical device includes a lens, and the control module emits sensing light to different areas of the field of view by illuminating light sources at different locations in a time-division manner.

3. The transmitting module as described in claim 1, characterized in that, The emitting optical device includes at least one light deflection device, and the control module controls the deflection angle of the passing light beam by the light deflection device to deflect the sensing light to different regions of the field of view in a time-division manner.

4. The transmitting module as described in claim 3, characterized in that, The at least one optical deflection device is selected from one or more combinations of acousto-optic deflectors, liquid crystal polarization gratings, electro-optic polarizers, and liquid crystal optical phased arrays.

5. The transmitting module as described in claim 1, characterized in that, The light source module includes multiple light sources, and the control module is further configured to control the sensing light emitted by one of the light sources to be emitted by the emitting optics to a corresponding partition within the field of view during a sensing period.

6. The transmitting module as described in claim 5, characterized in that, The control module is further configured to control the corresponding light source to emit multiple sensing light pulses according to a preset time sequence within a sensing period. The sensing period includes multiple pulse periods corresponding to the multiple sensing light pulses respectively. The control module is configured to control a light source to emit one sensing light pulse corresponding to a pulse period.

7. The transmitting module as described in claim 6, characterized in that, The control module is further configured to control at least two light sources that emit light during the same sensing period to emit sensing light pulses at different times during a pulse period.

8. The transmitting module as described in claim 7, characterized in that, The sensing light pulses emitted by the at least two light sources during the same sensing period are respectively emitted to different sections of the field of view.

9. The transmitting module as described in claim 6, characterized in that, The control module is further configured to control the at least two light sources to have a time difference between the times when they emit sensing light pulses within a pulse period, and the time difference formed by the at least two light sources in different pulse periods varies randomly.

10. The transmitting module as described in claim 6, characterized in that, The control module is further configured to control the multiple light sources that emit light during the same sensing period to emit sensing light pulses at times corresponding to each other within a pulse period, wherein the time differences formed by the multiple light sources in different pulse periods vary randomly.

11. The transmitting module as described in claim 9 or 10, characterized in that, The pulse period includes a preset duration of light emission time adjustment interval. Different light sources that emit light within the same sensing period emit sensing light pulses at random times within the light emission time adjustment interval. The random variation range of the time difference is greater than or equal to zero and less than or equal to the preset duration of the light emission time adjustment interval.

12. The transmitting module as described in claim 5, characterized in that, The control module is further configured to control the area illuminated by the light source module and / or the emitting optics within the same sensing period to include two partitions, with other partitions spaced between the two partitions.

13. A lidar, characterized in that, include: The transmitting module as described in any one of claims 1-12; and The receiving module includes multiple sensing pixels, each of which corresponds to a different partition in the field of view. The sensing pixels are configured to receive light signals from the corresponding partition and output corresponding light sensing signals for corresponding detection. The control module is configured to control the sensing pixels corresponding to the overlapping portion to perform one detection each in the first sensing period and the second sensing period.

14. The lidar as described in claim 13, characterized in that, The receiving module further includes a processing module configured to perform statistical analysis on the time of the pixel output light sensing signal according to a preset time resolution; the control module is further configured to control the processing module to perform statistical analysis on the time of the sensor pixel output light sensing signal corresponding to the overlapping part at a first time resolution during a first sensing period, and to perform statistical analysis on the time of the sensor pixel output light sensing signal corresponding to the overlapping part at a second time resolution during a second sensing period; wherein the second time resolution is higher than the first time resolution.

15. The lidar as described in claim 14, characterized in that, The processing module is further configured to generate a first histogram based on statistical analysis of the time of light signal output by the sensing pixel during a first sensing period, wherein the time range covered by the first histogram is divided into multiple time bins at a first time resolution; the control module is further configured to determine at least one time bin with a peak or near a peak in the first histogram as a target time bin, and control the processing module to perform statistical analysis on the time when the sensing pixel outputs light sensing signal within the target time bin only at a second time resolution during a second sensing period to generate a second histogram, and to perform corresponding detection based on the second histogram.

16. The lidar as described in claim 15, characterized in that, In the first histogram, a time bin has a time segment that partially overlaps with the time segments of two adjacent time bins before and after it. If the output time of the photosensitive signal is within the overlapping time segment, the processing module is configured to add a counter corresponding to the photosensitive signal in each of the two time bins that include the overlapping time segment.

17. The lidar as described in claim 15, characterized in that, The pulse width of the sensing light pulse is equal to the duration of a time bin in the first histogram, or the difference between the pulse width and the duration of a time bin in the first histogram is less than a preset threshold.

18. An electronic device, characterized in that, Including the lidar as described in any one of claims 13-17.

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