Laser radar and method for obtaining characteristic information

Abstract

The present application discloses a laser radar and a method for obtaining characteristic information, which belongs to the field of laser detection technology. Among them, the laser radar includes: at least two single-point emitters, at least two single-point detectors and at least one first beam splitter prism, at least one first beam splitter prism includes at least two light-emitting directions; each of the at least two light-emitting directions corresponds to at least one single-point detector, and at least two single-point emitters correspond one-to-one to at least two single-point detectors. The laser radar provided by the present application, by setting at least one first beam splitter prism, allows at least two light-emitting directions to correspond to at least one single-point detector, which is conducive to reducing the size of the laser radar and enhancing the applicability of the laser radar.

Description

Technical Field

[0001] The present application relates to the field of laser detection technology, and in particular to a laser radar and a method for acquiring characteristic information. Background Art

[0002] With the development of laser detection technology, people have higher and higher requirements for detection accuracy, and single-point transceiver devices have emerged. Compared with traditional linear array transceiver devices, single-point transceiver devices have higher detection accuracy because they avoid crosstalk problems. Among them, the single-point transceiver device includes a single-point transmitter for emitting laser light, and a single-point detector for detecting an echo formed by the laser reflected by a target object, such as an object.

[0003] In the related art, the laser radar includes at least two single-point transmitters spliced ​​together, and at least two single-point detectors spliced ​​together, so as to achieve the same scanning effect as the linear array transceiver device through the single-point transceiver device.

[0004] However, the size of the at least two spliced ​​single-point emitters and the at least two spliced ​​single-point detectors is large, which leads to a larger size of the laser radar, reducing the applicability of the laser radar. Summary of the invention

[0005] The embodiment of the present application provides a laser radar and a method for obtaining characteristic information to solve the problem that the laser radar is larger in size due to the use of a single-point transceiver device in the related art. The technical solution provided by the embodiment of the present application includes the following aspects.

[0006] In one aspect, a laser radar is provided, the laser radar comprising: at least two single-point emitters, at least two single-point detectors and at least one first beam splitter prism, wherein the at least one first beam splitter prism comprises at least two light emitting directions;

[0007] 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 one-to-one to the at least two single-point detectors, so that each single-point detector detects a 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 beam splitter prism, 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.

[0008] In an exemplary embodiment, the laser radar further includes at least one second beam splitter prism, wherein the at least one second beam splitter 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 emitter.

[0009] In an exemplary embodiment, the at least two single-point emitters are divided into at least two columns, and the single-point emitters in at least two columns are staggered.

[0010] In an exemplary embodiment, when each light incident direction corresponds to at least two single point emitters, the at least two single point emitters corresponding to each light incident direction are divided into at least two columns, and the single point emitters in at least two columns are staggered.

[0011] In an exemplary embodiment, when each light emitting direction corresponds to at least two single-point detectors, the at least two single-point detectors corresponding to each light emitting direction are divided into at least two columns, and the at least two columns of single-point detectors are staggered.

[0012] In a second aspect, a method for acquiring feature information is provided, the method being applied to a controller, the controller being used to control a laser radar provided in the first aspect and any exemplary embodiment of the first aspect, the method comprising:

[0013] The controller controls at least two single-point emitters to emit at least two lasers to a target object, the target object is used to reflect the at least two lasers to form at least two echoes, each of the at least two echoes is divided into at least two sub-echoes by at least one first beam splitter prism, and the at least two sub-echoes correspond to at least two light emitting directions one by one;

[0014] The controller controls at least two single-point detectors to respectively detect corresponding sub-echoes to obtain at least two ranging points, wherein the sub-echoes corresponding to each single-point detector are obtained by dividing the echo corresponding to the single-point detector, 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;

[0015] The controller splices the at least two ranging points, and acquires feature information of the target object based on the spliced ​​at least two ranging points.

[0016] In an exemplary embodiment, the controller controls at least two single-point emitters to emit at least two lasers toward a target object, including: the controller controls each single-point emitter to emit a laser toward at least one second beam splitter prism according to a corresponding light incident direction, so that the at least one second beam splitter prism emits the at least two lasers toward the target object, wherein the at least one second beam splitter prism includes at least two light incident directions, and each light incident direction corresponds to at least one single-point emitter.

[0017] In an exemplary embodiment, the controller controls at least two single-point emitters to emit at least two lasers toward a target object, including: the controller controls each group of at least two groups of single-point emitters to take turns to emit lasers toward the target object, each group of single-point emitters including at least one single-point emitter.

[0018] 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 to respectively detect the sub-echoes corresponding to the single-point detector to obtain a 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.

[0019] 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.

[0020] The beneficial effects of the technical solution provided by the embodiment of the present application include at least:

[0021] The laser radar provided in the embodiment of the present application, by setting at least one first beam splitting prism, allows at least two light emitting directions to correspond to at least one single-point detector respectively, which is beneficial to reducing the size of the laser radar and enhancing the applicability of the laser radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 is a schematic diagram of the structure of a laser radar provided in an embodiment of the present application;

[0024] Figure 2 is a schematic structural diagram of an array laser transmitter provided in an embodiment of the present application;

[0025] Figure 3 is a schematic diagram of the structure of an array laser detector provided in an embodiment of the present application;

[0026] Figure 4 This is a schematic diagram of a one-to-one correspondence between a single-point emitter and a single-point detector provided in an embodiment of the present application;

[0027] Figure 5 is a schematic diagram of a first beam splitter prism provided in an embodiment of the present application;

[0028] Figure 6is a schematic diagram of the relative position relationship between a first beam splitter prism and an array laser detector provided in an embodiment of the present application;

[0029] Figure 7 It is a front view and a top view of the relative position relationship between a first beam splitter prism and an array laser detector provided in an embodiment of the present application;

[0030] Figure 8 is a schematic diagram of the relative position relationship between a second beam splitter prism and an array laser emitter provided in an embodiment of the present application;

[0031] Fig. 9 is a flow chart of a method for obtaining feature information provided by an embodiment of the present application;

[0032] Fig.10 It is a schematic diagram of an embodiment of the present application in which each sub-echo covers multiple single-point detectors. DETAILED DESCRIPTION

[0033] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0034] In the field of laser detection technology, laser radar is a device used to measure distance, and pulse laser radar is one type of laser radar. Based on pulse laser radar, the relevant technology provides a TOF (Time Of Flight) method, which calculates the distance to the object based on the flight time (also known as the propagation time) and flight speed (also known as the propagation speed) of the laser pulse. For example, the time when the laser radar sends a laser pulse to the object is t0, and the time when the laser radar receives the echo (formed by the laser pulse reflected by the object) is t1, then the flight time of the laser pulse is Δt=t1-t0, and the flight speed of the laser pulse is recorded as c, then the distance l to the object is calculated according to the following formula:

[0035]

[0036] Each measurement of the LiDAR, that is, each time a laser pulse is emitted, can only obtain one ranging point, which represents the distance information between the LiDAR and the object. To achieve three-dimensional scanning of the scene, the LiDAR needs to scan in both horizontal and vertical dimensions to form 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 of the scanned scene can be generated.

[0037] Among them, scanning in both horizontal and vertical dimensions requires the use of a scanning system. If a linear array transceiver is used, the scanning system can be omitted in one dimension. Among them, a linear array transceiver integrates multiple transceivers in the vertical direction, and the scanning system can be used only in the horizontal direction, but not in the vertical direction. Alternatively, if a planar array transceiver is used, the scanning system can be omitted in both dimensions.

[0038] Eliminating the scanning system can simplify the structure of the laser radar and improve its reliability. However, due to the high cost of area array transceiver devices, linear array transceiver devices are currently mainly used, such as: a linear array laser transmitter for emitting lasers, which integrates multiple emitting units in the vertical direction; a linear array laser detector for detecting echoes, which integrates multiple detection units in the vertical direction.

[0039] One problem with linear array transceivers is crosstalk. The specific manifestation of the crosstalk problem is that when a detection unit of the linear array laser detector detects an object with high reflectivity (such as a license plate, road sign, etc.), it will cause other nearby detection units or even all detection units to produce a strong or weak response. This is reflected in the output point cloud, where the point cloud corresponding to the object with high reflectivity will "expand", that is, the distance measurement points in the point cloud that originally did not belong to the object also carry the same distance information as the object with high reflectivity, resulting in point cloud distortion.

[0040] The root cause of the crosstalk problem is related to the process of the linear array laser detector. Since all the detection units are integrated together, that is, the anodes of all the detection units are all connected to the same metal substrate, and the cathodes of all the detection units are connected to the external amplifier as their respective output stages. Therefore, when a certain detection unit detects strong reflected light (that is, the echo formed by the reflection of the laser by the object), it will cause a violent photoelectric effect in the detection unit, thereby affecting the potential of all anodes located on the same metal substrate, and then the corresponding "crosstalk" to the adjacent detection units or even all the detection units, causing all the crosstalked detection units to produce the same response as the detection unit, which is reflected in the ranging result as the "expansion" of the point cloud corresponding to the high-reflectivity object mentioned above. The crosstalk problem is currently a design and process problem, and it is often not repaired by adding new hardware or software in the signal processing process. It can be said that the crosstalk problem is an unavoidable problem when using linear array laser detectors.

[0041] Another problem with linear array transceivers 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 between the transmitting unit and the detection unit. When a special arrangement is required in the laser radar, it may be difficult to select a suitable linear array transceiver.

[0042] The use of single-point transceiver devices can solve the two problems existing in linear array transceiver devices. Single-point transceiver devices include single-point transmitters and single-point detectors. Single-point transceiver devices are independently set, and the anodes are not integrated on the same metal substrate, thus avoiding the above-mentioned crosstalk problem. In addition, independent single-point transceiver devices can be flexibly spliced, thereby realizing flexible arrangement of multiple single-point transceiver devices.

[0043] However, compared with linear array transceiver devices, single-point transceiver devices also have certain shortcomings. For example, splicing single-point transceiver devices will result in a larger size, thereby increasing the size of the laser radar, which is not conducive to the design of small-size integrated laser radars. 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 lines spliced ​​together. Therefore, in response to the technical problems existing in single-point transceiver devices, the embodiments of the present application provide a laser radar, as well as a method for obtaining feature information based on the laser radar, as described below.

[0044] The present application embodiment provides a laser radar, such as Figure 1 As shown, the laser radar includes at least two single-point emitters, at least two single-point detectors and at least one first beam splitter prism, and the at least one first beam splitter prism includes at least two light-emitting 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.

[0045] The laser radar is used to obtain characteristic information of the target object, and the target object is, for example, a person, an object, etc. in a three-dimensional space, and the characteristic information is, for example, the distance between the laser radar and the target object, etc., which is not limited here. Each single-point transmitter is used to transmit a beam of laser to the target object, and the target object can reflect the laser to form an echo. At least one dichroic prism is used to receive the echo and divide the echo into at least two sub-echoes, so that at least two sub-echoes correspond one-to-one to at least two light-emitting directions, that is, there is a sub-echo corresponding to the echo in each light-emitting direction. Since each light-emitting direction corresponds to at least one single-point detector, and at least two single-point transmitters correspond one-to-one to at least two single-point detectors, no matter which light-emitting direction the single-point detector corresponding to the single-point transmitter used to emit the laser corresponds to, the single-point detector can detect the sub-echo.

[0046] Thus, 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 detected by a single-point detector corresponding to the single-point emitter in the form of a sub-echo. Afterwards, for each single-point emitter, based on the emission time (i.e., t0) of the laser emitted by the single-point emitter, and the detection time (i.e., t1) when the single-point detector corresponding to the single-point emitter detects the sub-echo, a ranging point can be calculated according to the TOF method described above, and the ranging point represents a distance between the laser radar and the target object.

[0047] Among them, the above-mentioned emission time and detection time can be obtained through a timing chip. For example, when the single-point transmitter emits a laser, it sends a signal to the timing chip, and the timing chip records the moment when the signal is received as the emission time. When the single-point detector detects a sub-echo, the sub-echo may obey a Gaussian distribution, or other distributions similar to a Gaussian distribution. Therefore, the 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 moment when the signal is received as the detection time. Exemplarily, the timing chip can be integrated inside the laser radar, or it can be independently set outside the laser radar, which is not limited here.

[0048] The above describes the process of obtaining a ranging point based on a corresponding pair of single-point transmitters and single-point detectors. Since the laser radar includes at least two single-point transmitters and at least two single-point detectors corresponding to each other, at least two single-point transmitters can synchronously emit lasers once respectively, thereby obtaining at least two lasers. The target object reflects at least two lasers to obtain at least two echoes, and at least one first beam splitter prism divides each echo into at least two sub-echoes, so that there are at least two sub-echoes in each light-emitting direction. At least two single-point detectors can detect the corresponding sub-echoes respectively, that is, each single-point detector detects the corresponding sub-echo, so that at least two ranging points can be obtained according to the above description, and the at least two 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 beam splitter prism, and the echo corresponding to the single-point detector is formed by the laser emitted by the single-point transmitter corresponding to the single-point detector reflected by the target object. The sub-echo corresponding to a single-point detector is, that is, the sub-echo of the echo formed after the laser emitted by the single-point transmitter corresponding to the single-point detector is reflected in the light emitting direction corresponding to the single-point detector.

[0049] It can be seen that at least two single-point transmitters synchronously emit lasers once respectively, and a column of ranging points can be obtained, and the column of ranging points includes at least two ranging points, and characteristic information of the target object can be obtained based on the at least two ranging points. Exemplarily, synchronously emitting lasers can mean that the angles and times of emitting lasers from different single-point transmitters are slightly different, so that at least two lasers emitted by different single-point transmitters can reach the target object at the same time, and at least one first beam splitter prism can also receive at least two echoes at the same time.

[0050] For example, during a laser radar scan (i.e., 360 degrees), at least two single-point transmitters will synchronously emit lasers multiple times, and 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.

[0051] Next, various possible structures of the laser radar are explained respectively.

[0052] For a single-point transmitter, the following cases are included: Case A1 and Case A2.

[0053] Case A1: the at least two single-point emitters are located in the same column.

[0054] 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 at least two columns of single-point emitters is to make the light-emitting areas of different single-point emitters staggered, so as to avoid the lasers emitted by the light-emitting areas of different single-point emitters from overlapping.

[0055] For example, Figure 2 An array laser emitter is shown, in which at least two single-point emitters are located in two columns. Each square represents the external package of a single-point emitter. Each circle represents the light-emitting area of ​​a single-point emitter, which is also the area for emitting laser light, such as a laser diode, etc. Of course, the square and circle are only examples. Figure 2 The eight single-point emitters are only examples and are not used to limit the shape or number of the single-point emitters. The number of single-point emitters can be increased or decreased according to actual needs. Compared with situation A1, having at least two single-point emitters located in at least two columns can reduce the length of the array laser emitter, thereby facilitating the reduction of the size of the laser radar.

[0056] certainly, Figure 2In the illustrated case, the left column of single-point emitters is higher than the right column of single-point emitters for example only and is not intended to limit the relative positional relationship of the columns of single-point emitters. For example, the right column of single-point emitters may be higher than the left column of single-point emitters. Alternatively, if at least two single-point emitters are located in three or more columns, the columns of single-point emitters may be raised from left to right (or from right to left), or the middle columns of single-point emitters may be higher than the columns of single-point emitters on both sides, which are not listed here one by one.

[0057] For a single-point detector, the following cases are included: Case B1 and Case B2.

[0058] Case B1, at least two single-point detectors are located in the same column.

[0059] Case B2, when each light emitting 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 staggered. The purpose of staggering at least two columns 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 a one-to-one correspondence between at least two single-point emitters and at least two single-point detectors. Compared with case B1, the situation where at least two single-point detectors are located in at least two columns can reduce the length of the array laser detector, which is beneficial to reducing the size of the laser radar. Taking a 32-line array laser detector as an example, the array laser detector needs to splice 32 single-point detectors. If the 32 single-point detectors are spliced ​​into one column according to case 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.

[0060] For example, Figure 3 An array laser detector is shown, in which at least two single-point detectors are located in two columns. Each square represents the external package of a single-point detector. Each ellipse represents the photosensitive area of ​​a single-point detector, and the photosensitive area is also the area used to detect sub-echoes, such as APD (Avalanche Photon Diode). The square and ellipse are only examples, and the number of single-point detectors is also only examples, and is 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 situation A2 for the case where at least two single-point emitters are located in three or more columns, which will not be repeated here.

[0061] For the single-point emitters corresponding to at least two single-point detectors, the following cases C1 and C2 are included.

[0062] In case C1, the single-point emitters corresponding to the single-point detectors in the same array laser detector are not continuous. For example, see Figure 4 , the array laser emitter includes CH 1 to CH 8, a total of 8 single-point emitters. 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. 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 CH1, CH 3, CH 5 and CH7. Among them, CH represents channel.

[0063] In case C2, the single-point emitters corresponding to the single-point detectors in the same array laser detector are continuous. For example, they may be partially continuous or completely continuous.

[0064] Still taking the example that the array laser emitter includes 8 single-point emitters from CH 1 to CH 8, partial continuity can be that the 4 single-point detectors included in the array laser detector 1 correspond to the 4 single-point emitters CH 1, CH 2, CH 5 and CH 6 respectively, CH 1 is continuous with CH 2, CH 2 is not continuous with CH 5, and CH 5 is continuous with CH 6, so it is partially continuous. In addition, the 4 single-point detectors included in the array laser detector 2 correspond to the 4 single-point emitters CH 3, CH 4, CH 7 and CH 8 respectively. CH 3 is continuous with CH 4, CH 4 is not continuous with CH 7, and CH 7 is continuous with CH 8, so it is partially continuous.

[0065] Alternatively, all continuous can be that 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, and CH 1 to CH 4 are all continuous, so they can be all continuous. In addition, 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, and CH 1 to CH 8 are all continuous, so they are all continuous.

[0066] It should be understood that other partial or full continuity situations may also be set according to actual needs, which are not listed one by one here.

[0067] Based on the above cases C1 and C2, it can be seen that in the embodiment of the present application, different light emitting directions correspond to different single-point detectors, and the single-point detectors corresponding to different light emitting directions 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 one of the at least two light emitting directions.

[0068] The first beam splitter prism includes the following case D1 and case D2.

[0069] In case D1, a first beam splitter prism only includes two light emitting directions. Therefore, when two light emitting directions are required, the laser radar only needs to include one first beam splitter prism. When three or more light emitting directions are required, the laser radar needs to include at least two first beam splitter prisms. Among them, the first beam splitter prism includes two light emitting directions, and at least one of the two light emitting directions may further include at least one other first beam splitter prism. Of course, other first beam splitter prisms also include two light emitting directions, and at least one of the two light emitting directions may continue to include other first beam splitter prisms, or may not include other first beam splitter prisms.

[0070] In case D2, a first beam splitter prism may include three or more light emitting directions. Then, no matter how many light emitting directions are required, the laser radar may only include one first beam splitter prism.

[0071] In an exemplary embodiment, compared to the echo received by the first beam splitter prism, the energy of the sub-echo divided by the first beam splitter prism is smaller. For example, when a first beam splitter prism includes only two light emitting directions, the energy of each sub-echo is half of the energy of the echo. Based on this, the embodiment of the present application can increase the energy of the laser emitted by the single-point transmitter to ensure that the sub-echo has sufficient energy to avoid affecting the maximum measurement distance of the laser radar. For example, the embodiment of the present application can ensure that the maximum measurement distance of the laser radar remains unchanged by doubling the energy of the laser emitted by the single-point transmitter. Of course, even if the energy of the sub-echo obtained by division is not lower than 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 laser radar.

[0072] For example, see Figure 5 , the directions of the sub-echoes corresponding to the different light-emitting directions of each first beam splitter prism may be different, for example, the directions of the two sub-echoes are perpendicular. Therefore, different array laser detectors in the laser radar may need to be set in different ways to match the directions of the sub-echoes. For example, Figure 6 The relative position relationship between a different first beam splitter prism and an array laser detector is shown. It should be noted that: Figure 6 The first beam splitter prism in FIG. 1 is only shown in a plan view and not in a stereo view, in order to avoid blocking the array laser detector. For example, the first beam splitter prism may be Figure 5 The three-dimensional beam splitter prism shown. And, Figure 6 The optical gap shown refers to the distance between the array laser detector and the first beam splitter prism, and the optical gap is used for the array laser detector to normally detect sub-echoes.

[0073] It should be understood that Figure 6 The volume of the first beam splitter prism shown is only an example, and the volume of the first beam splitter prism is not necessarily larger than the array laser detector.

[0074] Observe from the front and top directions Figure 6 , we can get Figure 7 The front view (1) and top view (2) are shown. Figure 7 It can be seen from (1) that the height of the laser radar in the normal direction can be the length of the array laser detector. Figure 7 It can be seen from (2) that the height of the laser radar 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. The laser radar has a small size.

[0075] Taking the laser radar including two 32-line array laser detectors as an example, 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 laser radar can be 17.23 mm. In addition, the laser radar provided in the embodiment of the present application can achieve scanning with a resolution of 64 lines in the vertical direction. If the first beam splitter prism is not used and a single-point detector is used directly, 64 single-point detectors need to be spliced ​​separately to achieve scanning with a resolution of 64 lines in the vertical direction, and the length of the spliced ​​64 single-point detectors is about 64 mm. If a linear array laser detector is used, the size of the 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 embodiment of the present application can reduce the size of the laser radar while achieving the same resolution.

[0076] In an exemplary embodiment, see Figure 8 The laser radar further includes at least one second beam splitter prism, which includes at least two light incident directions, and each of the at least two light incident directions corresponds to at least one single point emitter. That is, the single point emitter corresponding to each light incident direction emits sub-lasers to the at least one second beam splitter prism according to the corresponding light incident direction, and the at least one second beam splitter prism then aggregates the sub-lasers into lasers and emits lasers to the target object.

[0077] Exemplarily, 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 staggered. The at least two single-point emitters corresponding to each incident light direction are located in at least two columns, as can be seen from the above case A1, which will not be elaborated here.

[0078] To sum up, the laser radar provided in the embodiment of the present application, by setting at least one first beam splitter prism, allows at least two light emitting directions to correspond to at least one single-point detector respectively, which is beneficial to reducing the size of the laser radar and enhancing the applicability of the laser radar.

[0079] The present application also provides a method for obtaining characteristic information, which can be applied to a controller for controlling the above Figures 1 to 8 The laser radar shown. The controller can be integrated into the laser radar or independently arranged outside the laser radar. The controller can be a processor, a chip or other components with control functions, etc., which are not limited here.

[0080] like Fig. 9 As shown, the method for obtaining characteristic information includes the following steps 901 to 903.

[0081] Step 901, a controller controls at least two single-point transmitters to emit at least two lasers toward a target object, the target object is used to reflect the at least two lasers to form at least two echoes, each of the at least two echoes is divided into at least two sub-echoes by at least one first beam splitter prism, and the at least two sub-echoes correspond one-to-one to at least two light emitting directions.

[0082] Wherein, the controller can control at least two single-point emitters to emit laser synchronously. Alternatively, the controller can group at least two single-point emitters to obtain at least two groups of single-point emitters, each group of single-point emitters includes at least one single-point emitter, and then the controller can control each group of single-point emitters to emit light in turn, and this light-emitting mode is also called polling light-emitting. In the process of taking turns to emit light, after a group of single-point emitters emit lasers and complete detection, the next group of single-point emitters emit lasers again. Wherein, the total time required for a group of single-point emitters to emit lasers and complete detection is the sum of multiple times, and the total time is, for example, in the order of 1-10 microseconds. Exemplarily, the multiple times include but are not limited to: the time required for the controller to send an instruction to the single-point emitter, the instruction is used to control the single-point emitter to emit lasers; the time for the laser emitted by the single-point emitter to be transmitted to the surface of the target object; the time for the echo to be transmitted to at least one first beam splitter prism after the target object reflects the laser to form an echo; the time for the single-point detector to detect the sub-echo after the echo is divided into sub-echoes; the time for the timing chip to perform timing and the controller to calculate the ranging point.

[0083] That is, in an exemplary embodiment, the controller controls at least two single-point emitters to emit at least two lasers toward a target object, including: the controller controls each group of single-point emitters in at least two groups of single-point emitters to emit lasers toward the target object in turn. For the single-point emitters in the same group, the controller can control these single-point emitters to emit lasers synchronously.

[0084] In an exemplary embodiment, a controller controls at least two single-point emitters to emit at least two lasers toward a target object, including: the controller controls each single-point emitter to emit a laser according to the corresponding incident light direction of at least one second beam splitter prism, so that at least one second beam splitter prism emits at least two lasers toward the target object, wherein at least one second beam splitter prism includes at least two incident light directions, and each incident light direction corresponds to at least one single-point emitter. The manner in which each single-point emitter emits a laser according to the corresponding incident light direction can be seen in the above description. Figure 8 The corresponding instructions are not repeated here.

[0085] Step 902: The controller controls at least two single-point detectors to respectively detect corresponding sub-echoes to obtain at least two ranging points, wherein the sub-echo corresponding to each single-point detector is obtained by dividing the echo corresponding to the single-point detector, 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.

[0086] If the controller controls at least two single-point emitters to emit lasers synchronously, at least two single-point detectors can synchronously detect the corresponding sub-echoes. Alternatively, if the controller controls each group of single-point emitters to emit light in turn, each single-point detector corresponding to each group of single-point emitters will synchronously detect the corresponding sub-echoes, and each single-point detector corresponding to different groups of single-point emitters will detect the corresponding sub-echoes in turn.

[0087] In some embodiments, a sub-echo corresponding to a laser emitted by a single-point emitter is detected only by a single-point detector corresponding to the single-point emitter. Figure 4 , the sub-echo corresponding to the laser emitted by the single-point transmitter of CH 3 can only be detected by the single-point detector of CH3.

[0088] In other embodiments, the sub-echo corresponding to the laser emitted by a single-point emitter will not only be detected by the single-point detector corresponding to the single-point emitter, but also by other single-point detectors adjacent to the single-point detector. The reason is that the laser will continue to diverge during the flight, and a sub-echo may not only cover the photosensitive area of ​​the corresponding single-point detector, but also cover part or all of the photosensitive areas of other adjacent single-point detectors. For example, see Fig.10 , the sub-echo corresponding to the laser emitted by the single-point transmitter of CH 3 will be detected by the single-point detector of CH 3, and will also be detected by the single-point detectors of CH 2 and CH 4. The sub-echo corresponding to the laser emitted by the single-point transmitter of CH 6 will be detected by the single-point detector of CH 6, and will also be detected by the single-point detectors of CH 5 and CH 7.

[0089] 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 and a first number of other single-point detectors adjacent to the single-point detector to respectively detect sub-echoes corresponding to the single-point detector to obtain a second number of sub-echoes corresponding to the single-point detector, and 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. It can be understood that the second number is the first number plus one.

[0090] It should be noted that this embodiment is applicable to the case 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 separated by the single-point emitters corresponding to the first number of channels. Fig.10 In the case shown, the first number is two, and the adjacent single-point transmitters in each group of single-point transmitters also need to be separated by two single-point transmitters. Then the single-point transmitters corresponding to CH 1, CH 4, and CH 7 are a group, and there are two single-point transmitters corresponding to channels between CH 1 and CH 4, and there are two single-point transmitters corresponding to channels between CH 4 and CH 7. The single-point transmitters corresponding to CH 2, CH 5, and CH 8 are a group, and the single-point transmitters corresponding to CH 3 and CH 6 are a group.

[0091] Among them, the energy of the sub-echoes detected by different detectors is different. For a single-point detector, the laser emitted by the single-point transmitter corresponding to the single-point detector can be detected by the single-point detector with the maximum energy corresponding to the laser. The energy of the sub-echo detected by other single-point detectors adjacent to the single-point detector is smaller, for example, about 5% of the sub-echo with the maximum energy. This is not limited here, and the energy of the sub-echoes detected by different other single-point detectors can be the same or different. In this way, a second number of sub-echoes with different energies corresponding to the single-point detector is obtained.

[0092] Since different sub-echoes have different energies, and according to the above description, sub-echoes can obey Gaussian distribution, the rising edges and falling edges of different sub-echoes have different slopes, and the higher the energy, the greater the slope. Since a single-point detector sends a signal to the timing chip when the rising edge of the detected sub-echo reaches a certain first threshold, the time when the single-point detector that detects sub-echoes with different energies sends a signal to the timing chip is different, and the time when the timing chip detects the sub-echo is also different. Therefore, the distance calculated based on each sub-echo is also different. The second number of sub-echoes can obtain a second number of ranging points. The embodiment 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.

[0093] For example, see Fig.10 After the single-point transmitter corresponding to CH 3 emits laser light, the single-point detectors corresponding to CH 2, CH 3, and CH 4 detect sub-echoes respectively, and three ranging points are calculated. Based on the three ranging points, a comprehensive calculation is performed to obtain a relatively accurate ranging point of the single-point detector corresponding to CH 3. By way of example, the comprehensive calculation includes but is not limited to selecting one of them, weighted summation, etc., which are not limited here.

[0094] It should be noted that a sub-echo with a larger energy corresponds to a larger ranging blind area 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 area can be reduced and the distance measurement range can be increased.

[0095] Exemplarily, pulse width correction can also be implemented based on a second number of sub-echoes with different energies. 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 be the same or different. Accordingly, different pulse widths can be determined for sub-echoes detected by different single-point detectors, and the embodiment of the present application performs pulse width correction based on different pulse widths.

[0096] 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 pulse width compensation value corresponding to the difference, so as to compensate the pulse width and realize the pulse width correction. Through the pulse width correction, the calculated ranging point can be made more accurate.

[0097] For example, see Fig.10 After the single-point transmitter corresponding to CH 3 emits laser light, the single-point detectors corresponding to CH 2, CH 3, and CH 4 detect sub-echoes respectively, and the time when each sub-echo reaches the first threshold is different, thereby obtaining three different times. Therefore, the difference between the three different times can be calculated first, and then the correction information can be queried based on the difference to obtain the pulse width compensation value corresponding to the difference, and then the pulse width compensation value can be used to compensate the pulse width detected by the single-point detector corresponding to CH 3, so that the ranging point corresponding to CH3 is more accurate.

[0098] 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 next single-point detector adjacent to the single-point detector are used as the other single-point detectors. Of course, it is easy to understand that for the first single-point detector, only the next single-point detector adjacent to the single-point detector can be used as the other single-point detector, and for the last single-point detector, only the previous single-point detector adjacent to the single-point detector can be used as the other single-point detector.

[0099] Step 903: The controller splices at least two ranging points, and acquires feature information of the target object based on the spliced ​​at least two ranging points.

[0100] The controller splices at least two ranging points to obtain at least two spliced ​​ranging points, and the at least two ranging points form a column of ranging points, which can be used to obtain feature information of the target object. For example, the column of ranging points is directly used to obtain feature information of the target object, or the column of ranging points and other ranging points are combined into a point cloud, and the point cloud is used to obtain feature information of the target object.

[0101] The controller may splice the obtained column of distance measurement points based on a one-to-one correspondence between at least two single-point transmitters and at least two single-point detectors. Fig.10 Taking the shown situation as an example, the array laser detector 1 can obtain four ranging points corresponding to CH2, CH4, CH6 and CH8, and the array laser detector 2 can obtain four ranging points corresponding to CH1, CH3, CH5 and CH7. These ranging points are staggered and spliced ​​to obtain a column of 8 ranging points, which are the ranging points corresponding to CH1 to CH8 from top to bottom.

[0102] In summary, the embodiment of the present application controls a relatively small laser radar through a controller, and can obtain characteristic information of a target object while ensuring resolution. Furthermore, it can also reduce the ranging blind area and realize pulse width correction.

[0103] All the above optional technical solutions can be arbitrarily combined to form optional embodiments of the present application, which will not be described one by one here.

[0104] The above description is only an embodiment of the present application and is 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.

Claims

1. A laser radar, characterized in that: The laser radar comprises: at least two single-point emitters, at least two single-point detectors and at least one first beam splitter prism, wherein the at least one first beam splitter prism comprises at least two light emitting directions, wherein any first beam splitter prism comprises only two light emitting directions, or any first beam splitter prism comprises at least three light emitting 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 one-to-one to the at least two single-point detectors, so that each single-point detector detects a 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 beam splitter prism, 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, and each echo is divided into at least two sub-echoes by the at least one first beam splitter prism, and the at least two sub-echoes correspond one-to-one to at least two light emitting directions.

2. The laser radar according to claim 1, characterized in that: The laser radar also includes at least one second beam splitter prism, and the at least one second beam splitter 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 emitter.

3. 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 single-point emitters in at least two columns are staggered.

4. The laser radar according to claim 3, characterized in that: When each light incident direction corresponds to at least two single point emitters, the at least two single point emitters corresponding to each light incident direction are divided into at least two columns, and the single point emitters in at least two columns are staggered.

5. The laser radar according to claim 1 or 2, characterized in that: When each light emitting direction corresponds to at least two single-point detectors, the at least two single-point detectors corresponding to each light emitting direction are divided into at least two columns, and the at least two columns of single-point detectors are staggered.

6. 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. The method comprises: The controller controls at least two single-point transmitters to emit at least two lasers to a target object, the target object is used to reflect the at least two lasers to form at least two echoes, each of the at least two echoes is divided into at least two sub-echoes by at least one first beam splitter prism, the at least one first beam splitter prism includes at least two light emitting directions, and the at least two sub-echoes correspond to the at least two light emitting directions one by one, wherein any first beam splitter prism includes only two light emitting directions, or any first beam splitter prism includes at least three light emitting directions; The controller controls at least two single-point detectors to respectively detect corresponding sub-echoes to obtain at least two ranging points, wherein the sub-echoes corresponding to each single-point detector are obtained by dividing the echo corresponding to the single-point detector, 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; The controller splices the at least two ranging points, and acquires feature information of the target object based on the spliced ​​at least two ranging points.

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

8. The method according to claim 6, characterized in that The controller controls at least two single-point emitters to emit at least two lasers toward a target object, including: The controller controls each group of at least two groups of single-point emitters to take turns to emit laser light toward the target object, and each group of single-point emitters includes at least one single-point emitter.

9. 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 sub-echoes corresponding to the single-point detector, so as to obtain a second number of sub-echoes corresponding to the single-point detector; For each single-point detector, the controller obtains a ranging point corresponding to the single-point detector based on the second number of sub-echoes.

10. The method according to claim 9, characterized in that The first number is two, and for each single-point detector, the single-point detector is located between two other single-point detectors.

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