WO2024026742A1

WO2024026742A1 - Laser radar and feature information acquisition method

Info

Publication number: WO2024026742A1
Application number: PCT/CN2022/110029
Authority: WO
Inventors: 李洪鹏; 郑睿童; 涂川
Original assignee: 探维科技(北京)有限公司
Priority date: 2022-08-02
Filing date: 2022-08-03
Publication date: 2024-02-08
Also published as: CN115436962A

Abstract

A laser radar and a feature information acquisition method, relating to the technical field of laser detection. The laser radar comprises at least two single-point emitters, at least two single-point detectors and at least one first beam splitter prism; the at least one first beam splitter prism comprises at least two light exit directions; each of the at least two light exit directions respectively corresponds to at least one single-point detector, and the at least two single-point emitters are in one-to-one correspondence to the at least two single-point detectors. The laser radar is provided with the at least one first beam splitter prism, so that the at least two light exit directions can correspond to the at least one single-point detector, respectively, thereby facilitating reduction of the size of the laser radar, and enhancing the applicability of the laser radar.

Description

Lidar and methods for obtaining feature information

This application claims priority to the Chinese patent application with application number 202210923605.2 and the invention title "Lidar and method for obtaining characteristic information" submitted on August 2, 2022, the entire content of which is incorporated into this application by reference.

Technical field

The present application relates to the field of laser detection technology, and in particular to a laser radar and a method for obtaining characteristic information.

Background technique

With the development of laser detection technology, people have higher and higher requirements for detection accuracy, and single-point transceiver devices have emerged as the times require. Compared with traditional line array transceiver devices, single-point transceiver devices have higher detection accuracy because they avoid crosstalk problems. The single-point transceiver device includes a single-point transmitter for emitting laser light, and a single-point detector for detecting the echo formed by the reflected laser light from a target object, such as an object.

In related art, lidar includes at least two single-point transmitters spliced together, and at least two single-point detectors spliced together, so that the same scanning effect as a linear array transceiver device can be achieved through a single-point transceiver device.

However, the size of the spliced at least two single-point emitters and the spliced at least two single-point detectors is larger, resulting in a larger size of the lidar, which reduces the applicability of the lidar.

Contents of the invention

Embodiments of the present application provide a lidar and a method for obtaining characteristic information to solve the problem in related technologies that the use of single-point transceiver devices results in a larger size of the lidar. The technical solutions provided by the embodiments of this application include the following aspects.

In a first aspect, a lidar is provided. The lidar includes: at least two single point emitters, at least two single point detectors and at least one first dichroic prism. The at least one first dichroic prism includes at least Two light emission directions;

Each of the at least two light emitting directions corresponds to at least one single point detector, and the at least two single point emitters correspond to the at least two single point detectors one by one, so that each single point The detector detects the corresponding sub-echo, and the sub-echo corresponding to the single-point detector is obtained by dividing the echo corresponding to the single-point detector by the at least one first dichroic prism. The echo corresponding to the single-point detector It is formed by the target object reflecting the laser light emitted by the single point emitter corresponding to the single point detector.

In an exemplary embodiment, the lidar further includes at least one second light splitting prism, the at least one second light splitting prism includes at least two light incident directions, each of the at least two light incident directions Corresponds to at least one single point emitter.

In an exemplary embodiment, the at least two single point emitters are divided into at least two columns, and the at least two columns of single point emitters are arranged in a staggered manner.

In an exemplary embodiment, when each incident light direction corresponds to at least two single point emitters, the at least two single point emitters corresponding to each incident light direction are divided into at least two columns, and the at least two columns of single point emitters The device is misaligned.

In an exemplary embodiment, when each light emission direction corresponds to at least two single-point detectors, the at least two single-point detectors corresponding to each light emission direction are divided into at least two columns, and the at least two columns of single-point detectors are misaligned arrangement.

A second aspect provides a method for obtaining characteristic information, the method being applied to a controller, the controller being used to control the lidar provided in the first aspect and any exemplary embodiment of the first aspect, the Methods include:

The controller controls at least two single-point emitters to emit at least two lasers to a target object, and the target object is used to reflect the at least two lasers to form at least two echoes. Each echo is divided into at least two sub-echoes through at least one first beam splitting prism, and the at least two sub-echoes correspond one-to-one to at least two light emission directions;

The controller controls at least two single-point detectors to detect corresponding sub-echoes respectively to obtain at least two ranging points, wherein the sub-echo corresponding to each single-point detector is divided into corresponding sub-echoes of the single-point detector. The echo is obtained, and the echo corresponding to the single-point detector is formed by the target object reflecting the laser emitted by the single-point emitter corresponding to the single-point detector;

The controller splices the at least two ranging points, and obtains the characteristic information of the target object based on the spliced at least two ranging points.

In an exemplary embodiment, the controller controls at least two single-point emitters to emit at least two lasers to the target object, including: the controller controls each single-point emitter to emit at least two lasers according to the corresponding incident light direction. A second dichroic prism emits a laser, so that the at least one second dichroic prism emits the at least two lasers to the target object, wherein the at least one second dichroic prism includes at least two incident light directions, each Each incident light direction corresponds to at least one single point emitter.

In an exemplary embodiment, the controller controls at least two single point emitters to emit at least two lasers to the target object, including: the controller controls each group of single point emitters in at least two groups of single point emitters. The laser is emitted to the target object in turn, and each group of single point emitters includes at least one single point emitter.

In an exemplary embodiment, the controller controls at least two single-point detectors to respectively detect corresponding sub-echoes to obtain at least two ranging points, including: for each single-point detector, the controller controls The single-point detector and a first number of other single-point detectors adjacent to the single-point detector respectively detect the sub-echoes corresponding to the single-point detector, and obtain the third sub-echo corresponding to the single-point detector. Two numbers of sub-echoes; for each single-point detector, the controller obtains the ranging point corresponding to the single-point detector based on the second number of sub-echoes.

In an exemplary embodiment, the first number is two, and for each single point detector, the single point detector is located between two other single point detectors.

The beneficial effects brought by the technical solutions provided by the embodiments of this application at least include:

The lidar provided by the embodiments of the present application disposes at least one first light splitting prism so that at least two light emission directions can respectively correspond to at least one single-point detector, thereby conducive to reducing the size of the lidar and enhancing the applicability of the lidar.

Description of the drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of a laser radar provided by an embodiment of the present application;

Figure 2 is a schematic structural diagram of an array laser emitter provided by an embodiment of the present application;

Figure 3 is a schematic structural diagram of an array laser detector provided by an embodiment of the present application;

Figure 4 is a schematic diagram of one-to-one correspondence between a single-point transmitter and a single-point detector provided by an embodiment of the present application;

Figure 5 is a schematic diagram of a first beam splitting prism provided by an embodiment of the present application;

Figure 6 is a schematic diagram of the relative positional relationship between a first beam splitter prism and an array laser detector provided by an embodiment of the present application;

Figure 7 is a front view and a top view of the relative positional relationship between a first beam splitting prism and an array laser detector provided by an embodiment of the present application;

Figure 8 is a schematic diagram of the relative positional relationship between a second beam splitting prism and an array laser emitter provided by an embodiment of the present application;

Figure 9 is a flow chart of a method for obtaining feature information provided by an embodiment of the present application;

Figure 10 is a schematic diagram in which each sub-echo covers multiple single-point detectors provided by an embodiment of the present application.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

In the field of laser detection technology, lidar is a device used to measure distances, and pulse lidar is one type of lidar. Based on pulse lidar, related technology provides a TOF (Time Of Flight) method, which calculates and The distance between objects. For example, the time when the lidar sends a laser pulse to the object is t ₀ , and the time when the lidar receives the echo (formed by the reflected laser pulse from the object) is t ₁ , then the flight time of the laser pulse is Δt=t ₁ -t ₀ , and The flight speed of the laser pulse is recorded as c, and the distance l between the laser pulse and the object is calculated according to the following formula:

Each measurement of the lidar, that is, each time a laser pulse is emitted, only one ranging point can be obtained. This ranging point represents a distance information between the lidar and the object. If you want to achieve three-dimensional scanning of the scene, you need to let the laser Radar scans in both horizontal and vertical dimensions, resulting in a uniformly or non-uniformly distributed point cloud. Combined with the distance information carried by each ranging point in the point cloud, a three-dimensional point cloud image of the scanned scene can be generated.

Among them, scanning in both horizontal and vertical dimensions depends on the scanning system. If linear array transceivers are used, the scanning system can be eliminated in one dimension. Among them, the linear array transceiver device integrates multiple transceiver devices in the vertical direction, so the scanning system can be used only in the horizontal direction instead of in the vertical direction. Alternatively, if an area array transceiver is used, the scanning system can be eliminated in both dimensions.

Eliminating the scanning system can simplify the structure of the lidar and improve the reliability of the lidar. However, due to the high cost of area array transceiver devices, line array transceiver devices are currently mainly used. Line array transceiver devices are, for example, linear array laser transmitters for emitting lasers, which integrate multiple transmitting units in the vertical direction. ; A linear array laser detector used to detect echoes, integrating multiple detection units in the vertical direction.

One problem with line array transceiver devices is crosstalk. The specific manifestation of the crosstalk problem is that when a certain detection unit of the linear array laser detector detects a highly reflective object (such as a license plate, road sign, etc.), it will cause other nearby detection units or even all detection The unit produces a stronger or weaker response. Reflected in the output point cloud, the point cloud corresponding to a high reflectivity object will "expand", that is, the ranging points in the point cloud that no longer belong to the object also carry the high reflectivity Objects with different rates have the same distance information, resulting in point cloud distortion.

The root cause of the crosstalk problem is related to the process of the linear array laser detector. Since all detection units are integrated together, that is, the anodes of all detection units are all connected to the same metal base, and the cathodes of all detection units serve as their respective Output stage, connected to an external amplifier. Therefore, when a certain detection unit detects strong reflected light (that is, the echo formed by the object's reflection of the laser), it will cause a violent photoelectric effect in the detection unit, thus affecting all anodes located on the same metal substrate. potential, and then cause corresponding "crosstalk" to adjacent detection units or even all detection units, causing all detection units subject to crosstalk to produce the same response as the detection unit, which is reflected in the ranging results as the above-mentioned high reflectivity The point cloud corresponding to the object is "inflated". Crosstalk problems are currently a design and process issue that often cannot be fixed by adding new hardware or software to the signal processing process. It can be said that the crosstalk problem is an unavoidable problem when using linear array laser detectors.

Another problem with linear array transceiver devices is that the arrangement of the transmitting unit of the linear array laser transmitter and the above-mentioned detection unit is relatively rigid and inflexible. Due to cost and other reasons, there are often only a few fixed arrangements for the arrangement of the transmitting unit and the detecting unit. When a special arrangement is required in a lidar, it may be difficult to select a suitable line array transceiver device.

The two problems existing in linear array transceiver devices can be solved by using single-point transceiver devices. Single-point transceiver devices include single-point transmitters and single-point detectors. The single-point transceiver device is set up independently, and the anode is not integrated on the same metal substrate, thus avoiding the above-mentioned crosstalk problem. Moreover, independent single-point transceiver devices can be flexibly spliced together, thereby enabling flexible arrangement of multiple single-point transceiver devices.

However, compared with line array transceiver devices, single-point transceiver devices also have certain shortcomings. For example, splicing single-point transceiver devices will lead to a larger size, thereby increasing the size of the lidar, which is not conducive to the design of small-sized integrated lidar. For example, the length of a 64-line linear array laser detector is about 17.7 mm, while the spliced single-point detector has a length of 16 mm with only 16 spliced lines. Therefore, to address the technical problems existing in single-point transceiver devices, embodiments of the present application provide lidar and a method for obtaining characteristic information based on lidar. Please refer to the following description.

Embodiments of the present application provide a lidar, as shown in Figure 1 . The lidar includes at least two single-point emitters, at least two single-point detectors, and at least one first dichroic prism. At least one first dichroic prism Include at least two light emission directions. Each of the at least two light emitting directions corresponds to at least one single point detector, and the at least two single point emitters correspond to the at least two single point detectors in a one-to-one manner.

Among them, the lidar is used to obtain characteristic information of a target object. The target object is, for example, a person, an object, etc. in a three-dimensional space. The characteristic information is, for example, the distance between the lidar and the target object, etc., which is not limited here. Each single point emitter is used to emit a laser beam to the target object, and the target object can reflect the laser beam to form an echo. At least one beam splitter prism is used to receive the echo and divide the echo into at least two sub-echoes. This makes at least two sub-echoes correspond to at least two light emitting directions one-to-one, that is, there is a sub-echo corresponding to the echo in each light emitting direction. Since each light emission direction corresponds to at least one single-point detector, and at least two single-point emitters correspond to at least two single-point detectors, no matter the single-point detector used to emit the laser corresponds to the single-point emitter Whichever light emission direction the detector corresponds to, the single-point detector can detect the sub-echo.

As a result, the laser emitted by each of the at least two single-point emitters and the echo formed by the reflection of the target object can be reflected in the form of sub-echoes by a single point emitter corresponding to the single-point emitter. Point detector detected. Afterwards, for each single-point transmitter, based on the emission time when the single-point transmitter emits laser light (i.e. t ₀ ), and the detection time when the single-point detector corresponding to the single-point emitter detects the sub-echo (i.e. t ₁ ), a ranging point can be calculated according to the TOF method explained above, which represents a distance between the lidar and the target object.

Among them, the above-mentioned emission time and detection time can be obtained through a timing chip. For example, when a single-point transmitter emits a laser, it sends a signal to the timing chip, and the timing chip records the time when the signal is received as the emission time. When a single-point detector detects a sub-echo, the sub-echo can obey a Gaussian distribution or other distributions similar to a Gaussian distribution. Therefore, this sub-echo has a rising edge and a falling edge. When the rising edge of the sub-echo reaches a certain first threshold, the single-point detector sends a signal to the timing chip, and the timing chip records the time when the signal is received as the detection time. For example, the timing chip can be integrated inside the lidar, or can be independently installed outside the lidar, which is not limited here.

The above explains the process of obtaining a ranging point based on a corresponding pair of single-point transmitters and single-point detectors. Since the lidar includes at least two single-point emitters and at least two single-point detectors in one-to-one correspondence, the at least two single-point emitters can simultaneously emit laser once, thereby obtaining at least two lasers. The target object reflects at least two laser beams to obtain at least two echoes, and at least one first beam splitting prism divides each echo into at least two sub-echoes, so that there are at least two sub-echoes in each light emission direction. At least two single-point detectors can detect corresponding sub-echoes respectively, that is, each single-point detector detects corresponding sub-echoes, so that at least two ranging points can be obtained according to the above description, and the at least two ranging points can be obtained. ranging points are located in the same column. Among them, the sub-echo corresponding to the single-point detector is obtained by dividing the echo corresponding to the single-point detector by at least one first dichroic prism. The echo corresponding to the single-point detector is reflected by the target object and the single-point emission corresponding to the single-point detector is reflected. formed by the laser emitted by the device. The sub-echo corresponding to a single-point detector is the sub-echo in the light emission direction corresponding to the echo formed after the laser emitted by the single-point transmitter corresponding to the single-point detector is reflected. .

It can be seen that at least two single-point emitters emit lasers once synchronously, and a row of ranging points can be obtained. The row of ranging points includes at least two ranging points, and the characteristics of the target object can be obtained based on at least two ranging points. information. For example, synchronously emitting lasers may mean that different single-point emitters emit lasers at slightly different angles and times, so that at least two lasers emitted by different single-point emitters can reach the target object and at least one first dichroic prism at the same time. It is also possible to receive at least two echoes simultaneously.

For example, during the lidar scanning process of one cycle (that is, 360 degrees), at least two single-point emitters will simultaneously emit lasers multiple times, and then multiple columns of ranging points can be obtained, each column of ranging points including at least two ranging points. The multiple columns of ranging points can form a frame of point cloud, so that the characteristic information of the target object can be obtained based on the frame of point cloud.

Next, various possible structures of the lidar will be described respectively.

For single-point transmitters, include case A1 and case A2 as follows.

Case A1, the at least two single point emitters are located in the same column.

In case A2, at least two single-point emitters are divided into at least two columns, and at least two columns of single-point emitters are arranged in a staggered manner. The purpose of staggering the arrangement of at least two rows of single-point emitters is to cause the light-emitting areas of different single-point emitters to be staggered and avoid overlapping of lasers emitted by the light-emitting areas of different single-point emitters.

For example, FIG. 2 shows an array laser transmitter in which at least two single-point emitters are located in two columns. Where, each square represents the external package of a single point emitter. Each circle represents the luminous area of a single-point emitter, which is the area used to emit laser light, such as a laser diode, etc. Of course, the square and circular shapes are only examples, and the eight single-point emitters in Figure 2 are also only examples and are not used to limit the shape or number of single-point emitters. The number of single-point emitters can be determined according to actual needs. increase or decrease. Compared with case A1, locating at least two single-point emitters in at least two columns can reduce the length of the array laser emitter, thereby conducive to reducing the size of the lidar.

Of course, in the situation shown in Figure 2, the fact that the single-point emitters in the left column are higher than the single-point emitters in the right column is only an example and is not used to limit the relative positional relationship of the single-point emitters in each column. For example, the single-point emitters in the right column may be higher than the single-point emitters in the left column. Alternatively, if at least two single-point emitters are located in three or more columns, it can be that the single-point emitters in each column are ascending from left to right (or from right to left), or that the single-point emitters in the middle column The emitter is higher than the rows of single-point emitters on both sides, which are not listed here.

For single-point detectors, the following cases B1 and B2 are included.

Case B1, at least two single-point detectors are located in the same column.

In case B2, when each light emission direction corresponds to at least two single-point detectors, the at least two single-point detectors are divided into at least two columns, and the at least two columns of single-point detectors are arranged in a staggered manner. The purpose of the staggered arrangement of at least two rows of single-point detectors is to enable the photosensitive areas of different single-point detectors to correspond one-to-one with different single-point emitters, thereby ensuring that at least two single-point emitters are aligned with at least two single-point emitters. One-to-one correspondence of detectors. Compared with case B1, the case where at least two single-point detectors are located in at least two columns can reduce the length of the array laser detector, thereby conducive to reducing the size of the lidar. Take the 32-line array laser detector as an example. This array laser detector needs to be spliced into 32 single-point detectors. If the 32 single-point detectors are spliced into one column according to situation B1, the length of the array laser detector is about 32 mm, and if the 32 single-point detectors are divided into two columns and spliced according to case B2, the length of the array laser detector is about 16 mm.

For example, FIG. 3 shows an array laser detector in which at least two single-point detectors are located in two columns. Where, each square represents the outer package of a single point detector. Each oval represents the photosensitive area of a single-point detector, which is the area used to detect sub-echoes, such as APD (Avalanche Photon Diode, avalanche photodiode). The square and elliptical shapes are only examples, and the number of single-point detectors is also only an example. They are not used to limit the shape or number of single-point detectors. The number of single-point detectors can be increased or decreased according to actual needs. In addition, for the case where at least two single-point detectors are located in three or more columns, please refer to the above case A2 for the case where at least two single-point emitters are located in three or more columns, which will not be described again here.

For single-point transmitters corresponding to at least two single-point detectors, the following situations C1 and C2 are included.

In case C1, the single-point emitters corresponding to each single-point detector located in the same array laser detector are discontinuous. For example, see Figure 4, the array laser transmitter includes CH 1 to CH 8, a total of 8 single-point transmitters. The array laser detector 1 includes 4 single-point detectors, and the 4 single-point emitters corresponding to the 4 single-point detectors are CH 2, CH 4, CH 6 and CH 8 respectively. The array laser detector 2 also includes 4 single-point detectors, and the 4 single-point emitters corresponding to the 4 single-point detectors are CH 1, CH 3, CH 5 and CH 7 respectively. Among them, CH represents channel.

In case C2, the single-point emitters corresponding to each single-point detector located in the same array laser detector are continuous. For example, it may be partially continuous or completely continuous.

Still taking the array laser transmitter including a total of 8 single-point emitters from CH 1 to CH 8 as an example, the partial continuity can be that the 4 single-point detectors included in the array laser detector 1 correspond to CH 1, CH 2, and CH 5 respectively. For the four single-point transmitters CH 6 and CH 1, CH 1 and CH 2 are continuous, CH 2 and CH 5 are discontinuous, and CH 5 and CH 6 are continuous, so they are partially continuous. Moreover, the four single-point detectors included in the array laser detector 2 correspond to the four single-point emitters CH 3, CH 4, CH 7 and CH 8 respectively. CH 3 and CH 4 are continuous, CH 4 and CH 7 are discontinuous, and CH 7 and CH 8 are continuous, so they are partially continuous.

Or, if all are continuous, the four single-point detectors included in the array laser detector 1 correspond to the four single-point emitters CH 1 to CH 4 respectively. CH 1 to CH 4 are all continuous, so they can be all continuous. Moreover, the four single-point detectors included in the array laser detector 2 correspond to the four single-point emitters CH 5 to CH 8 respectively. CH 1 to CH 8 are all continuous, so they are all continuous.

It should be understood that other partially continuous or fully continuous situations can also be set according to actual needs, and examples are not given here.

Based on the above situations C1 and C2, it can be seen that in the embodiment of the present application, different light emission directions correspond to different single-point detectors, and the single-point detectors corresponding to different light emission directions jointly correspond to at least two single-point emitters. . In other words, the single-point detector corresponding to each single-point emitter is only located in at least one of the two light-emitting directions.

For the first dichroic prism, the following cases D1 and D2 are included.

In case D1, a first dichroic prism only includes two light emission directions. Therefore, when two light emission directions are required, the lidar only needs to include a first beam splitting prism. When three or more light emission directions are required, the lidar needs to include at least two first beam splitting prisms. Wherein, the first dichroic prism includes two light emitting directions, and at least one of the two light emitting directions may further include at least one other first dichroic prism. Of course, other first beam splitting prisms also include two light emitting directions. At least one of the two light emitting directions may continue to include other first beam splitting prisms, or may not include other first beam splitting prisms.

In case D2, one first dichroic prism can include three or more light emitting directions, so no matter how many light emitting directions are required, the lidar can only include one first dichroic prism.

In an exemplary embodiment, the energy of the sub-echoes divided by the first dichroic prism is smaller than the echo received by the first dichroic prism. For example, when a first beam splitting prism only includes two light emission directions, the energy of each sub-echo is half of the energy of the echo. Based on this, embodiments of the present application can increase the energy of the laser emitted by the single-point transmitter to ensure that the sub-echoes have sufficient energy to avoid affecting the maximum measurement distance of the lidar. For example, the embodiment of the present application can ensure that the maximum measurement distance of the lidar remains unchanged by doubling the energy of the laser emitted by the single-point emitter. Of course, even if the energy of the divided sub-echoes is not lower than that of the echo, the embodiment of the present application can also adjust the energy of the laser emitted by the single-point transmitter according to actual needs, so as to flexibly adjust the ranging range of the lidar. .

For example, referring to FIG. 5 , the directions of sub-echoes corresponding to different light emission directions of each first dichroic prism may be different. For example, the directions of the two sub-echoes are vertical. Therefore, different arrays of laser detectors in a lidar may need to be set up in different ways to match the direction of the sub-echoes. For example, FIG. 6 shows the relative positional relationship between different first beam splitting prisms and array laser detectors. It should be noted that the first dichroic prism in FIG. 6 is only shown as a plan view and not as a three-dimensional view in order to avoid blocking the array laser detector. For example, the first dichroic prism may be a three-dimensional dichroic prism shown in FIG. 5 . Moreover, the optical gap shown in FIG. 6 refers to the distance between the array laser detector and the first dichroic prism, and the optical gap is used for normal detection sub-echoes of the array laser detector.

It should be understood that the volume of the first beam splitting prism shown in FIG. 6 is only an example, and the volume of the first beam splitting prism is not necessarily larger than the array laser detector.

6 is viewed from the front direction and the top view direction respectively, and the front view (1) and the top view (2) shown in Figure 7 can be obtained. Based on (1) of Figure 7, it can be seen that the height of the lidar in the front-view direction can be the length of the array laser detector. Based on (2) of Figure 7, it can be seen that the height of the lidar in the top view direction can be the sum of the length of the array laser detector, the thickness of the array laser detector, and the optical gap. This lidar has a smaller size.

Taking the lidar as an example, including two 32-line array laser detectors, the length of the array laser detector is 16 mm, the thickness of the array laser detector is 0.23 mm, and the optical gap is 1 mm, then the size of the lidar can be 17.23 mm. Moreover, the lidar provided by the embodiment of the present application can realize scanning with a resolution of 64 lines in the vertical direction. If the first dichroic prism is not used and a single-point detector is used directly, 64 single-point detectors need to be spliced to achieve a scan with a resolution of 64 lines in the vertical direction. The length of splicing 64 single-point detectors is about is 64 mm. If a linear array laser detector is used, the size of a linear array laser detector with a resolution of 64 lines in the vertical direction may reach 17.7 mm. It can be seen that the embodiments of the present application can reduce the size of the lidar while achieving the same resolution.

In an exemplary embodiment, referring to FIG. 8 , the lidar further includes at least one second light splitting prism. The at least one second light splitting prism includes at least two light incident directions, and each of the at least two light incident directions corresponds to At least one single point transmitter. That is to say, the single-point emitter corresponding to each light incident direction emits sub-lasers to the at least one second dichroic prism according to the corresponding light incidence direction, and the at least one second dichroic prism then summarizes the sub-lasers into laser light. Fires a laser at the target object.

For example, when each incident light direction corresponds to at least two single-point emitters, the at least two single-point emitters corresponding to each incident light direction are divided into at least two columns, and the at least two columns of single-point emitters are arranged in a staggered manner. . For at least two single-point emitters corresponding to each light incident direction to be located in at least two columns, please refer to the above situation A1, which will not be described again here.

To sum up, the lidar provided by the embodiments of the present application sets at least one first light splitting prism so that at least two light emission directions can respectively correspond to at least one single-point detector, thereby conducive to reducing the size of the lidar and enhancing the laser Radar suitability.

Embodiments of the present application also provide a method for obtaining characteristic information, which method can be applied to a controller used to control the lidar shown in FIGS. 1 to 8 above. The controller can be integrated inside the lidar, or can be independently installed outside the lidar. The controller can be a processor, a chip, or other components with control functions, etc., which are not limited here.

As shown in Figure 9, the method for obtaining feature information includes the following steps 901 to 903.

Step 901: The controller controls at least two single-point emitters to emit at least two lasers to the target object. The target object is used to reflect the at least two lasers to form at least two echoes, and each of the at least two echoes passes through At least one first beam splitting prism is divided into at least two sub-echoes, and the at least two sub-echoes correspond to at least two light emission directions one-to-one.

Wherein, the controller can control at least two single-point emitters to emit lasers synchronously. Alternatively, the controller can group at least two single-point transmitters to obtain at least two groups of single-point transmitters. Each group of single-point transmitters includes at least one single-point transmitter. Afterwards, the controller can control each group of single-point transmitters. The devices emit light in turns. This light-emitting mode is also called polling light-emitting. In the process of taking turns to emit light, one group of single-point emitters emits lasers and completes detection, and then the next group of single-point emitters emits lasers again. Among them, the total time required for a group of single-point emitters to emit lasers and complete detection is the sum of multiple times. The total time is, for example, on the order of 1-10 microseconds. Exemplarily, the multiple times include but are not limited to: the time required for the controller to send instructions to the single-point emitter, which instructions are used to control the single-point emitter to emit laser; the laser emitted by the single-point emitter is transmitted to the surface of the target object The time; after the target object reflects the laser to form an echo, the time for the echo to be transmitted to at least one first dichroic prism; after the echo is divided into sub-echoes, the time for the single-point detector to detect the sub-echoes; the timing chip performs timing and the time it takes for the controller to calculate the ranging point.

That is, in an exemplary embodiment, the controller controls at least two single-point emitters to emit at least two lasers to the target object, including: the controller controls each group of single-point emitters in at least two groups of single-point emitters. Take turns firing the laser at the target object. Among them, for the single-point emitters of the same group, the controller can control these single-point emitters to emit laser synchronously.

In an exemplary embodiment, the controller controls at least two single-point emitters to emit at least two lasers to the target object, including: the controller controls each single-point emitter to emit at least one second dichroic prism according to the corresponding incident light direction. A laser enables at least one second beam splitting prism to emit at least two laser beams to the target object, wherein the at least one second beam splitting prism includes at least two incident light directions, and each incident light direction corresponds to at least one single point emitter. Among them, the way in which each single-point emitter emits laser light according to the corresponding light incident direction can be referred to the corresponding description in Figure 8 above, and will not be described again here.

Step 902: The controller controls at least two single-point detectors to detect corresponding sub-echoes respectively to obtain at least two ranging points. The sub-echo corresponding to each single-point detector is divided into the sub-echoes corresponding to the single-point detector. The echo is obtained, and the echo corresponding to the single-point detector is formed by the target object reflecting the laser emitted by the single-point transmitter corresponding to the single-point detector.

Wherein, if the controller controls at least two single-point emitters to emit lasers synchronously, then at least two single-point detectors can synchronously detect corresponding sub-echoes. Or, if the controller controls each group of single-point emitters to emit light in turn, the single-point detectors corresponding to each group of single-point emitters will detect the corresponding sub-echoes synchronously, and the individual point detectors corresponding to different groups of single-point emitters will The single-point detector will detect the corresponding sub-echoes in turn.

In some embodiments, the sub-echo corresponding to the laser emitted by a single-point emitter is only detected by a single-point detector corresponding to the single-point emitter. For example, see Figure 4, the sub-echo corresponding to the laser emitted by the single-point emitter of CH3 will only be detected by the single-point detector of CH3.

In other embodiments, the sub-echo corresponding to the laser emitted by a single-point emitter will not only be detected by a single-point detector corresponding to the single-point emitter, but will also be detected by the adjacent single-point detector. Detection by other single point detectors. The reason is that the laser will continue to diverge during flight, and a sub-echo may not only cover the photosensitive area of a corresponding single-point detector, but may also cover part or all of the photosensitive areas of other adjacent single-point detectors. For example, see Figure 10, the sub-echo corresponding to the laser emitted by the single-point emitter of CH3 will be detected by the single-point detector of CH3, and will also be detected by the single-point detectors of CH2 and CH4. The sub-echo corresponding to the laser emitted by the CH 6 single-point transmitter will be detected by the CH 6 single-point detector, and will also be detected by the CH 5 and CH 7 single-point detectors.

Based on this, in an exemplary embodiment, the controller controls at least two single-point detectors to respectively detect corresponding sub-echoes to obtain at least two ranging points, including: for each single-point detector, the controller controls the single-point detector to detect corresponding sub-echoes respectively. The first number of other single-point detectors adjacent to the point detector and the single-point detector respectively detect the sub-echoes corresponding to the single-point detector, and obtain the second number of sub-echoes corresponding to the single-point detector, and for each A single point detector, the controller obtains the ranging point corresponding to the single point detector based on the second number of sub-echoes. It will be understood that the second quantity is the first quantity plus one.

It should be noted that this embodiment is applicable to the situation where each group of single-point emitters emits light in turn, and the adjacent single-point emitters in each group of single-point emitters are spaced apart by the distance corresponding to the first number of channels. Single point transmitter. For example, in the case shown in FIG. 10 , the first number is two, and two single-point transmitters need to be spaced between adjacent single-point transmitters in each group of single-point transmitters. Then the single-point transmitters corresponding to CH 1, CH 4, and CH 7 are a group. There are 2 channels of single-point transmitters corresponding to each other between CH 1 and CH 4. There are also 2 channels of corresponding single-point transmitters between CH 4 and CH 7. single point transmitter. The single-point transmitters corresponding to CH 2, CH 5, and CH 8 are one group, and the single-point transmitters corresponding to CH 3 and CH 6 are one group.

Among them, the sub-echoes detected by different detectors have different energies. For a single-point detector, the single-point detector corresponds to the laser emitted by the single-point emitter, and the single-point detector can detect a sub-echo with the highest energy corresponding to the laser. The energy of the sub-echoes detected by other single-point detectors adjacent to the single-point detector is smaller, for example, about 5% of the sub-echo with the largest energy. There is no limit here. Different other single-point detection The energy of the sub-echoes detected by the detector can be the same or different. Thus, a second number of sub-echoes with different energies corresponding to the single-point detector are obtained.

Since different sub-echoes have different energies, and according to the above description, the sub-echoes can obey Gaussian distribution, so the rising edges and falling edges of different sub-echoes have different slopes. The higher the energy, the greater the slope. Since a single-point detector will send a signal to the timing chip when the rising edge of the detected sub-echo reaches a certain first threshold, single-point detectors that detect sub-echoes of different energies send signals to the timing chip at different times. , then the time when the sub-echo is detected recorded by the timing chip is also different. Therefore, the distance calculated based on each sub-echo is also different. A total of a second number of ranging points can be obtained from the second number of sub-echoes. Embodiments of the present application can calculate a more accurate ranging point corresponding to the single-point detector based on the second number of ranging points.

For example, see Figure 10. After the single-point transmitter corresponding to CH 3 emits laser, the single-point detectors corresponding to CH 2, CH 3 and CH 4 respectively detect sub-echoes and calculate 3 ranging points. Based on these 3 By comprehensively calculating the ranging points, a more accurate ranging point of the single-point detector corresponding to CH 3 can be obtained. For example, comprehensive calculation includes but is not limited to any one, weighted summation, etc., which is not limited here.

It should be noted that the sub-echo with greater energy corresponds to a larger ranging blind zone and a larger maximum measurement distance. Since the embodiment of the present application uses a second number of sub-echoes with different energies, the ranging blind zone can be reduced and the distance measurement range can be increased.

For example, pulse width correction can also be implemented based on a second number of sub-echoes with different energies. The pulse width refers to the difference between the moment when the rising edge of the sub-echo reaches the first threshold and the moment when the falling edge of the sub-echo reaches the second threshold. The first threshold and the second threshold can The same can also be different. Correspondingly, for the sub-echoes detected by different single-point detectors, different pulse widths can be determined, and then the embodiment of the present application performs pulse width correction based on the different pulse widths.

For example, the embodiment of the present application can determine the different moments when the rising edge of the sub-echo detected by each single-point detector reaches the first threshold, calculate the difference between the different moments, and then query the correction information based on the difference to obtain the difference. The corresponding pulse width compensation value can be used to compensate the pulse width and achieve pulse width correction. Through pulse width correction, the calculated ranging points can be made more accurate.

For example, see Figure 10. After the single-point transmitter corresponding to CH 3 emits laser, the single-point detectors corresponding to CH 2, CH 3, and CH 4 detect sub-echoes respectively. The moment when each sub-echo reaches the first threshold is different. , thus obtaining 3 different moments. Therefore, you can first calculate the difference between these three different moments, then query the correction information based on the difference, get the pulse width compensation value corresponding to the difference, and then use the pulse width compensation value to detect the single point corresponding to CH 3 The pulse width detected by the detector is compensated to make the ranging point corresponding to CH3 more accurate.

In an exemplary embodiment, the first number is two, and for each single point detector, the single point detector is located between two other single point detectors. That is, for each single-point detector, the previous single-point detector adjacent to the single-point detector and the subsequent single-point detector adjacent to the single-point detector are regarded as the other single points mentioned above. detector. Of course, it is easy to understand that for the first single-point detector, only the adjacent subsequent single-point detector can be used as the other single-point detectors mentioned above, and for the last single-point detector, only the adjacent single-point detector can be used as The previous single point detector acts as the other single point detector above.

Step 903: The controller splices at least two ranging points, and obtains characteristic information of the target object based on the spliced at least two ranging points.

The controller splices at least two ranging points to obtain at least two spliced ranging points. The at least two ranging points form a row of ranging points. This row of ranging points can be used to obtain characteristic information of the target object. For example, directly use this series of ranging points to obtain the characteristic information of the target object, or combine this series of ranging points with other ranging points to form a point cloud, and use the point cloud to obtain the characteristic information of the target object.

The controller may splice the obtained sequence of ranging points based on a one-to-one correspondence between at least two single-point transmitters and at least two single-point detectors. Taking the situation shown in Figure 10 as an example, array laser detector 1 can obtain 4 ranging points corresponding to CH 2, CH 4, CH 6 and CH 8, while array laser detector 2 can obtain CH 1, CH 3 , 4 ranging points corresponding to CH 5 and CH 7. These ranging points are staggered and spliced to obtain a column of 8 ranging points. These 8 ranging points are from top to bottom corresponding to CH 1 to CH 8. ranging point.

To sum up, the embodiment of the present application uses a controller to control a smaller lidar, and can obtain feature information for a target object while ensuring resolution. Furthermore, the ranging blind area can also be reduced and pulse width correction can be achieved.

All the above optional technical solutions can be combined in any way to form optional embodiments of the present application, and will not be described again one by one.

The above are only examples of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application. Inside.

Claims

A lidar, characterized in that the lidar includes: at least two single-point emitters, at least two single-point detectors and at least one first dichroic prism, and the at least one first dichroic prism includes at least two light direction;

Each of the at least two light emitting directions corresponds to at least one single point detector, and the at least two single point emitters correspond to the at least two single point detectors one by one, so that each single point The detector detects the corresponding sub-echo, and the sub-echo corresponding to the single-point detector is obtained by dividing the echo corresponding to the single-point detector by the at least one first dichroic prism. The echo corresponding to the single-point detector It is formed by the target object reflecting the laser light emitted by the single point emitter corresponding to the single point detector.
The laser radar according to claim 1, characterized in that the laser radar further includes at least one second light splitting prism, the at least one second light splitting prism includes at least two light incident directions, and the at least two light incident directions Each incident light direction in the direction corresponds to at least one single point emitter.
The laser radar according to claim 1 or 2, characterized in that the at least two single point emitters are divided into at least two columns, and the at least two columns of single point emitters are arranged in a staggered manner.
The laser radar according to claim 3, characterized in that when each incident light direction corresponds to at least two single-point emitters, the at least two single-point emitters corresponding to each incident light direction are divided into at least two columns, And at least two rows of single-point emitters are arranged in a staggered manner.
The laser radar according to claim 1 or 2, characterized in that when each light emission direction corresponds to at least two single-point detectors, the at least two single-point detectors corresponding to each light emission direction are divided into at least two columns, And at least two rows of single-point detectors are misaligned.
A method for obtaining characteristic information, characterized in that the method is applied to a controller, and the controller is used to control the laser radar according to any one of claims 1 to 5, and the method includes:

The controller controls at least two single-point emitters to emit at least two lasers to a target object, and the target object is used to reflect the at least two lasers to form at least two echoes. Each echo is divided into at least two sub-echoes through at least one first beam splitting prism, and the at least two sub-echoes correspond one-to-one to at least two light emission directions;

The controller controls at least two single-point detectors to detect corresponding sub-echoes respectively to obtain at least two ranging points, wherein the sub-echo corresponding to each single-point detector is divided into corresponding sub-echoes of the single-point detector. The echo is obtained, and the echo corresponding to the single-point detector is formed by the target object reflecting the laser emitted by the single-point emitter corresponding to the single-point detector;

The controller splices the at least two ranging points, and obtains the characteristic information of the target object based on the spliced at least two ranging points.
The method of claim 6, wherein the controller controls at least two single-point emitters to emit at least two lasers to the target object, including:

The controller controls each single-point emitter to emit a laser to at least one second dichroic prism according to the corresponding incident light direction, so that the at least one second dichroic prism emits the at least two lasers to the target object. , wherein the at least one second light splitting prism includes at least two light incident directions, and each light incident direction corresponds to at least one single point emitter.
The method of claim 6, wherein the controller controls at least two single-point emitters to emit at least two lasers to the target object, including:

The controller controls each group of at least two groups of single-point emitters to emit laser light toward the target object in turn, and each group of single-point emitters includes at least one single-point emitter.
The method according to claim 8, characterized in that the controller controls at least two single-point detectors to respectively detect corresponding sub-echoes to obtain at least two ranging points, including:

For each single-point detector, the controller controls the single-point detector and a first number of other single-point detectors adjacent to the single-point detector to respectively detect the sub-units corresponding to the single-point detector. echo to obtain the second number of sub-echoes corresponding to the single-point detector;

For each single-point detector, the controller obtains the ranging point corresponding to the single-point detector based on the second number of sub-echoes.
The method of claim 9, wherein the first number is two, and for each single-point detector, the single-point detector is located between two other single-point detectors.