WO2021258709A1

WO2021258709A1 - Dispersion spectrum lidar system and measurement method

Info

Publication number: WO2021258709A1
Application number: PCT/CN2020/141728
Authority: WO
Inventors: 朱亮; 关健; 李国花; 闫敏
Original assignee: 深圳奥锐达科技有限公司
Priority date: 2020-06-25
Filing date: 2020-12-30
Publication date: 2021-12-30
Also published as: CN113848538A

Abstract

A dispersion spectrum lidar system and a method for using the system to perform measurement, the system comprising: an emitting end (12), configured to emit a signal light beam; a receiving end (15), comprising a receiving optical component (17) and a dispersion spectrum photosensitive component (16), wherein the receiving optical component (17) is used for receiving at least part of the signal light beam reflected by the target and part of the ambient light beam, and entering same into the dispersion spectrum photosensitive component (16), and the dispersion spectrum photosensitive component (16) disperses the incident light beam to distinguish light beams with different wavelengths in space; and a control and processing device (11) is used for controlling the dispersion spectrum photosensitive component (16) to filter for an incident beam signal with the same wavelength as the signal light beam, and calculating the flight time of photons on the basis of the incident beam signal. Filtering of the wavelength of the signal light is achieved by means of dispersion, thereby improving the signal-to-noise ratio and measurement accuracy.

Description

Dispersive spectrum lidar system and measurement method

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on June 25, 2020, the application number is 202010593041.1, and the invention title is "a dispersive spectrum lidar system and measurement method", the entire content of which is incorporated by reference In this application.

Technical field

This application relates to the technical fields of optical sensors and lidars, and in particular to a dispersive spectrum lidar system and measurement method.

Background technique

Lidar is an active three-dimensional measurement technology that emits a laser beam into space through the laser emitting end, and then receives the laser beam reflected by the object through the receiving end, and then processes the received optical signal to obtain the laser beam The flight time in space, according to the relationship between distance, photon flight time and speed of light, can calculate the distance and orientation information of the target. Ambient light interference is a common problem faced by current lidar systems, that is, when lidar is working under strong outdoor light, it is often interfered by the sun's ambient light, resulting in a certain degree of decrease in measurement distance and measurement accuracy.

In order to solve the problem of ambient light interference, existing solutions often choose near-infrared laser transmitters with relatively low solar spectral irradiance, and then use a narrowband filter near the band at the receiving end to further filter the ambient light. However, considering the practical problems in engineering, such as the manufacturing tolerance of the center wavelength of the laser transmitter, the manufacturing tolerance of the center transmission wavelength of the filter, the drift of the center wavelength of the laser transmitter with temperature, etc., the spectral transmission of the filter actually used The full width at half maximum of the pass rate is much larger than the full width at half maximum of the laser wavelength, so the effect of filtering the ambient light is very limited, resulting in lower signal-to-noise ratio and measurement accuracy.

Summary of the invention

The purpose of this application is to provide a dispersive spectrum lidar system and measurement method to solve at least one of the above-mentioned background technical problems.

The embodiment of the application provides a dispersive spectrum lidar system, including: a transmitting end configured to emit a signal light beam; a receiving end, including a receiving optical component and a dispersive spectrum photosensitive component; wherein the receiving optical component is used to receive at least Part of the signal light beam and part of the ambient light beam reflected by the target are incident on the dispersive spectrum photosensitive component, and the dispersive spectrum photosensitive component disperses the incident light beam to distinguish light beams of different wavelengths spatially; control; The processor is used for controlling the dispersive spectrum photosensitive component to filter out the incident light beam signal with the same wavelength as the signal light beam, and calculate the flight time of the photon based on the incident light beam signal.

In some implementations, the dispersive spectrum photosensitive component includes a dispersive device and a photosensitive detector; wherein the dispersive device disperses the incident light beam and emits it at different angles according to the wavelength, so that light beams of different wavelengths are incident on the Different spatial positions of the photosensitive detector.

In some implementations, the emitting end includes a light source and a emitting optical component, and the light source is used to emit a signal light beam and is modulated by the emitting optical component to emit to the target.

In some implementations, the signal light beam includes one of a spot beam, a line beam, and a flood beam.

In some implementations, the transmitting end includes at least one transmitting channel, and the receiving optical assembly includes at least one receiving channel; wherein, the transmitting channel and the receiving channel are in one-to-one correspondence.

In some implementations, the transmitting end and the receiving end are arranged in a coaxial form.

In some implementations, the transmitting end and the receiving end are arranged in an off-axis form.

In some implementations, the transmitting end and the receiving end are mounted on the same substrate.

In some implementations, it further includes a rotating platform for placing the transmitting end and the receiving end, and rotating under the control of the control and processor to realize scanning.

The embodiment of the present application also provides a measurement method using a dispersive spectrum lidar system, which includes the following steps:

Emit the signal light beam;

Receiving at least part of the signal light beam and part of the ambient light beam reflected back by the target;

Disperse the received incident light beam to distinguish light beams of different wavelengths spatially;

The incident light beam signal having the same wavelength as the signal light beam is filtered out, and the flight time of the photon is calculated based on the incident light beam signal.

The embodiment of the application provides a dispersive spectrum lidar system, including: a transmitting end configured to emit a signal light beam; a receiving end, including a receiving optical component and a dispersive spectrum photosensitive component; wherein the receiving optical component is used to receive at least Part of the signal light beam and part of the ambient light beam reflected by the target are incident on the dispersive spectrum photosensitive component, and the dispersive spectrum photosensitive component disperses the incident light beam to distinguish light beams of different wavelengths spatially; control; The processor is used for controlling the dispersive spectrum photosensitive component to filter out the incident light beam signal with the same wavelength as the signal light beam, and calculate the flight time of the photon based on the incident light beam signal. The present application addresses the problem of ambient light interference in lidar, which can more efficiently reduce the influence of ambient light and improve the detection range and accuracy of lidar.

Description of the drawings

In order to more clearly describe the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor.

Fig. 1 is a schematic diagram of the composition of a dispersive spectrum lidar according to an embodiment of the present application;

Fig. 2 is a schematic diagram of a mechanical scanning type dispersion spectrum lidar system according to an embodiment of the present application;

Fig. 3 is a schematic diagram of a non-mechanical scanning dispersive spectrum lidar system according to an embodiment of the present application;

4 is a schematic diagram of the composition of a receiving end of a dispersive spectrum lidar according to an embodiment of the present application;

Fig. 5a is a schematic diagram of a waveguide transmission element according to an embodiment of the present application;

Fig. 5b is a schematic diagram of a waveguide dispersive element according to an embodiment of the present application;

Fig. 6 is a schematic diagram of a receiving end of a lidar system containing an area-array dispersion spectrum photosensitive component according to an embodiment of the present application;

Fig. 7 is a schematic diagram of a receiving end of an area array dispersion spectrum lidar according to an embodiment of the present application;

Fig. 8 is a schematic diagram of a receiving end of an area-array dispersion spectrum lidar according to another embodiment of the present application;

9 is a schematic diagram of the receiving end of the area array dispersion spectrum lidar according to another embodiment of the present application;

10 is a schematic diagram of the receiving end of the area array dispersion spectrum lidar according to another embodiment of the present application;

FIG. 11 is a schematic diagram of a receiving end of an area array dispersion spectrum lidar according to another embodiment of the present application.

detailed description

In order to make the technical problems, technical solutions, and beneficial effects to be solved by the embodiments of the present application clearer, the following further describes the present application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not used to limit the present application.

It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, the connection can be used for fixing or circuit connection.

It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top" The orientation or positional relationship indicated by "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the application and simplifying the description, rather than indicating or implying what is meant. The device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application.

In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined with "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the embodiments of the present application, "a plurality of" means two or more than two, unless otherwise specifically defined.

Fig. 1 is a schematic diagram of a dispersive spectrum lidar system according to an embodiment of the application. The system 10 includes a transmitting terminal 12, a receiving terminal 15 and a control and processor 11; wherein the transmitting terminal 12 includes a light source 13 and a transmitting optical component 14; the receiving terminal 15 includes a dispersive spectrum photosensitive component 16 and a receiving optical component 17. The transmitting end 12 emits a laser beam (also known as a signal light beam) of a specific wavelength range through the light source 13, such as a laser beam with a wavelength near 960nm and 1550nm. The laser beam group is modulated by the transmitting optical component 14 and then emitted to the target space; receiving; The receiving optical component 17 in the end 15 is used to collect at least part of the laser beam reflected by the object in the target space and other beams from the ambient light, and enter the dispersive spectrum photosensitive component 16, and the dispersive spectrum photosensitive component 16 will The received light beam is dispersed in order to distinguish the incident light beam according to different wavelengths in space; the light beams of different wavelengths fall into different spatial positions, and the control and processor 11 controls the dispersion spectrum photosensitive component 16 and screens out only those with the transmitting end 12 The incident beam signal with the same central wavelength of the transmitted signal beam (specifically, the narrow-band wavelength beam signal within the range of the polar cell centered on the central wavelength of the transmitted signal beam. Theoretically, this range should include most of the signal light beam and polar A small number of ambient light beams), and calculate the flight time of the photon based on the incident beam signal, and further calculate the distance D of the target based on the flight time, namely:

D=c·t/2 (1)

Among them, c is the speed of light and t is the flight time.

Preferably, the dispersive spectrum photosensitive component 16 includes a dispersive device and a photosensitive detector, wherein the dispersive device disperses the incident light beam and emits it at different angles according to the wavelength, so that light beams of different wavelengths are incident on different spatial positions of the photosensitive detector. , So as to facilitate subsequent screening. Specific embodiments of the dispersion spectrum photosensitive component 16 will be described in detail later.

Through the dispersion function of the chromatic dispersion spectrum photosensitive component, the incident beam is spatially distinguished according to the wavelength, thereby filtering out the signal light. Compared with filtering only through the filter, the dispersion can locate the signal light very accurately, and the filtered light The bandwidth of the narrow-band beam is smaller than that of the filter, and it can filter out most of the ambient light noise, thereby greatly improving the accuracy and signal-to-noise ratio of the lidar system.

The system can be designed in different styles according to the functions and performance requirements of different lidars. For example, for long-distance lidar, the transmitting end 12 will emit a high-power laser beam, which is pre-modulated into spots, lines, etc., and the field of view covered by the entire laser beam is relatively small; For lidar, the transmitting end 12 can be configured to emit a low-power laser beam with a certain field of view, and the laser beam can be in the shape of flood, spot, line, etc. Similarly, the receiving end 15 is also specially designed to correspond to the transmitting end. Several specific embodiments will be described in detail later.

In some embodiments, the emitting end 12 is used to emit a single laser beam 18 into the space, and the laser beam 18 has a certain cross-sectional shape 20, such as a circular spot shape, an ellipse shape, a line shape, and the like. Correspondingly, the receiving beam assembly 17 in the receiving end 15 is used to collect the light beam within a certain field of view 19, and the field of view 19 of the receiving end 15 is designed to exactly correspond to the laser beam 18 through a certain design, so that the receiving end The laser beam reflected from the object in the target space can be collected to further calculate the flight time. Generally, the angle of view 19 is greater than the divergence angle of the laser beam 18. For ease of description, in the embodiments of the present application, a laser beam and the receiving end field angle corresponding to the laser beam are referred to as a channel, and the transmitting channel of the transmitting end corresponds to the receiving channel of the receiving end one to one, so as to realize the distance to the target object. Measurement. The channel can be any form of channel such as point channel, line channel, encoding channel and so on.

In FIG. 1, only a single channel is schematically drawn. In other embodiments, the system 10 may scan a single channel or multiple channels to achieve distance measurement with a larger field of view. For example, in some embodiments, the transmitting optical assembly 14 and/or the receiving optical assembly 17 are provided with beam scanning devices such as MEMS galvanometers, mechanical rotating mirrors, etc. to realize the scanning of the beams, thereby realizing multi-channel measurement. Of course, it can also be This is achieved by adding an additional beam scanning component. In some embodiments, the transmitting end 12 can simultaneously emit multi-channel laser beams. Correspondingly, the receiving end 15 also has multiple receiving channels one-to-one corresponding to the transmitting channels of the transmitting end 12, so that the target can be achieved at the same time. Multi-channel (such as dot matrix, linear matrix, etc.) scanning.

In some embodiments, the transmitting end 12 and the receiving end 15 are arranged in a coaxial form, for example, it can be achieved by adding optical elements such as a half mirror with reflection and transmission functions, a transflective mirror with a hole in the middle of the mirror, etc. , The coaxial form can ensure the one-to-one correspondence between the transmitting channel and the receiving channel. In some embodiments, the transmitting end 12 and the receiving end 15 are set in an off-axis form. Compared with coaxial, off-axis has lower hardware requirements and is easy to assemble. The disadvantage is that parallax needs to be considered. When the target is At different distances, there will be deviations between the transmitting channel and the receiving channel due to parallax. It can be understood that when the measurement distance is much larger than the baseline distance between the transmitting end and the receiving end, the parallax problem can also be ignored. When the measurement distance is relatively short, the parallax problem can be solved by means of calibration and spot positioning.

In some embodiments, the transmitting end and the receiving end are installed on the same substrate to facilitate the miniaturization and integration of the system. For example, a laser light source and a photosensitive chip can be manufactured on the same semiconductor substrate through a semiconductor process at the same time. Optical devices, electronic components, etc. are further mounted on the semiconductor substrate to form a transmitting end and a receiving end.

In some embodiments, the dispersive spectrum lidar is configured as a lidar system in the form of mechanical scanning. As shown in FIG. 2, the lidar system in the form of mechanical scanning includes a transmitting end 201, a receiving end 202, and a transmitting end for placing And the rotating platform 203 at the receiving end, the rotating platform 203 can be rotated in a certain direction 204 through a rotating component under the control of the control and processor 11, so as to realize a large-angle field of view (such as 360 degrees) scanning.

In some embodiments, the dispersive spectrum lidar is configured as a non-mechanical scanning lidar system. As shown in FIG. 3, the transmitting end 12 and the receiving end 15 of the non-mechanical scanning lidar system are configured to have a common In general, the transmitting end 12 is used to emit laser beams of multiple channels to illuminate the target in the common field of view, and the receiving end 15 is used to collect the reflections from the common field of view. Laser beam.

Based on the dispersive spectrum lidar system described in the foregoing embodiments, an embodiment of the present application also provides a measurement method based on the foregoing dispersive spectrum lidar. The method includes the following steps:

First, emit the signal light beam;

Secondly, receiving at least part of the signal light beam and part of the ambient light beam reflected back by the target;

Thirdly, disperse the received incident light beam to distinguish light beams of different wavelengths spatially;

Finally, the incident light beam signal having the same wavelength as the signal light beam is filtered out, and the flight time of the photon is calculated based on the incident light beam signal.

The above steps are specifically implemented by using the dispersive spectrum lidar system in the embodiment shown in FIGS. 1 to 3, and the detailed method steps can refer to the description in the embodiment shown in FIGS. 1 to 3, which will not be repeated here.

Fig. 4 is a schematic diagram of the composition of a receiving end of a dispersive spectrum lidar according to an embodiment of the present application. The receiving end includes a dispersive spectrum photosensitive component 41 and a receiving optical component 42; wherein the receiving optical component 42 is composed of at least one lens or lens array for receiving part of the laser beam (signal light) reflected by the object 46 in the target space, and Light beams from other ambient light in the environment. In this embodiment, a strip-shaped laser beam emitted by the transmitting end will be used as an example for description. It is understandable that the present application is not limited to strip-shaped beams. (Including signal light and ambient light) and is collected by the receiving optical group 42 and incident into the dispersive spectrum photosensitive component 41.

The dispersive spectrum photosensitive component 41 includes an aperture 415, a collimating device 414, a filter 413, a dispersive device 412, and an array detector 411 arranged in sequence along the incident light path; the light beam 47 reflected by the object 46 passes through the receiving optical component 42 and converges to The diaphragm 415 plane; the diaphragm limits the field of view of the receiving optical assembly 42, and only the reflected light beam received within the field of view can pass through the diaphragm and be further incident on the collimating device 414; the collimating device 414 will pass through The reflected beam of the diaphragm is collimated into a parallel beam, and the parallel beam is then incident on the filter 413; the filter 413 is a band-pass filter used to filter the incident beam, and only the center wavelength of the signal light is allowed The narrow-band wavelength light beam within a certain bandwidth is transmitted through the center and a certain bandwidth; generally, the pass-band wavelength of the filter 413 is set to be centered on the center wavelength of the signal light, and the half-maximum and full-width transmittance is usually tens of nanometers (for example only) ), but because the full width at half maximum of the signal light is much narrower than the bandwidth of the filter, most of the signal light and the ambient light in the ambient light with a few tens of nanometers near the center wavelength of the signal light will pass through the filter.

The narrow-band wavelength beam emitted by the filter 413 is incident on the dispersive device 412, and the dispersive device 412 disperses the incident narrow-band wavelength beam according to the wavelength in one direction, so that light of different wavelengths irradiate different positions on the surface of the array detector 411, such as The surface of the array detector 411 forms a plurality of light beams 43, 44, 45 arranged along the wavelength. Therefore, some pixels (such as 44) of the array detector 411 are only illuminated by the signal light and the ambient light with the same wavelength as the signal light, and the ambient light with a wavelength different from the signal light will no longer overlap the signal light spatially. For example, 43 and 45, the control and processor can subsequently read out only the signal in the corresponding pixel on the signal light band array detector 411, and calculate the flight time of the photon based on the read out light signal, and further can be based on the flight time. Calculate the distance to the target. By spatially distinguishing the dispersion, the ambient light from the narrow-band wavelength beam of the filter can be further filtered. Through the reasonable design of the dispersive device and the design of the array detector, it is theoretically possible to filter out only the signal within the bandwidth of the signal light. The light beam, compared with the filtering effect of only the optical filter, can further greatly reduce the noise from the ambient light, and finally achieve the suppression effect on the ambient light, and improve the measurement accuracy and the signal-to-noise ratio.

The aperture 415 is generally set on the focal plane of the receiving optical assembly 42, and the aperture 415 includes at least one hole or a slit. The arrangement and number of the holes or slits set determine the field of view angle of the dispersive spectrum photosensitive assembly 41. , Resolution and other optical performance; generally, according to the overall performance of the lidar system, the diaphragm needs to be set to a reasonable form. For example, for a single-channel lidar, if the transmitting end emits a line beam, the diaphragm can It only contains a single linear hole, that is, a single-slit diaphragm; if the emitting end emits a point-shaped beam, the diaphragm can only include a single circular hole, that is, a single-hole diaphragm. When the emitting end emits a planar light beam, the aperture can include multiple slits or multiple holes arranged in an array, that is, a multi-slit aperture or a multi-slit aperture, so that the array light signal can be received synchronously to obtain the depth of the array The measurement information will be described in detail later.

The position of the aperture or slit of the aperture can be fixed or movable in the plane where the aperture is located. When the position of the aperture or slit of the aperture is movable, the position of the aperture or slit The amount of movement is controlled by the control and processor. The movable diaphragm includes but is not limited to being realized by a MEMS mechanism, a liquid crystal device, and the like. In some embodiments, the opening and closing of the aperture or slit of the diaphragm can also be controlled by the control and processor. For a porous or multi-slit diaphragm, the holes or slits on the diaphragm can be arranged in a one-dimensional arrangement or a two-dimensional arrangement according to requirements, such as a regular two-dimensional array, an irregular two-dimensional array, etc.

In some embodiments, the array detector 411 is an array-type optical receiving device composed of a plurality of pixels, typically an APD (Avalanche Diode) array and a SPAD (Single Photon Avalanche Diode) array. The array detector can measure the flight time of the signal light reflected from the target back to the array detector. The pixels on the array detector include at least one column of pixels in a direction consistent with the dispersion direction.

In some embodiments, the collimating device may be composed of one or more combinations of at least one lens, a microlens array, a mirror (including a flat mirror, a curved mirror, a reflective prism, etc.), and a waveguide transmission element. .

For waveguide transmission elements, refer to Figure 5a, which is a schematic diagram of a waveguide transmission element according to an embodiment of the present application. The waveguide transmission element is composed of an incident coupler 51, a waveguide 52, and an exit coupler 53 for The light beam is transmitted in a three-dimensional space and emitted outward in a certain direction at a suitable position. The waveguide transmission element can make the function of the collimating device more extensive, for example, the spatial position and the emission direction of the collimated beam can be controlled according to needs. This will be explained later. The waveguide 52 in the waveguide transmission element may be an optical fiber. The waveguide can transmit light beams in a curved path in a three-dimensional space. The entrance coupler 51, the exit coupler 53, and the waveguide 52 can be independent non-on-chip devices, can also be implemented by an on-chip optical circuit, or can be a combination of on-chip devices and discrete non-on-chip devices.

In some embodiments, the filter 413 can be placed in other positions in the optical path, for example, it can be placed outside the aperture 415 (including placed between the receiving optical assembly 42 and the target object 46, or placed between the aperture 415 and the aperture 415). Between the receiving optical components 42), or between the aperture 415 and the collimating device 414, or between the collimating device 414 and the dispersive device 412, or between the dispersive device 412 and the array detector 411; preferably, filter The sheet 413 is placed between the collimating device 414 and the dispersing device 412.

The dispersive device 412 includes at least one dispersive element, such as a prism, a grating, and a combination of one or more of the dispersive holograms, which can form an incident beam with different wavelengths according to different wavelengths. Dispersion effect. Among them, the dispersion hologram is a holographic device that has both the dispersion function and the convergence function (or divergence function). In some embodiments, in addition to the dispersion element, the dispersive device 412 further includes one or a combination of a lens, a lens group, a microlens array, and a mirror.

In some embodiments, the dispersive element may also be a waveguide dispersive element, as shown in Fig. 5b. The waveguide dispersion element includes an entrance coupler 54, a beam splitter 56, a beam combiner 57, an exit coupler 58 and a waveguide 55. The incident light of the waveguide dispersive element is coupled into a single waveguide 55 through the incident coupler 54, and the other end of the waveguide is connected to the beam splitter 56. The beam splitter 56 distributes its incident light to the multiple waveguides connected between the beam splitter 56 and the combiner 57 according to equal intensity or non-equal intensity and equal phase. For the convenience of description, N waveguides are used for description. , The length of the N waveguides increases in a fixed increment. The number of N needs to be designed according to the dispersion resolution of the waveguide dispersion element. Generally, the larger the value of N, the higher the dispersion resolution of the waveguide dispersive element. Due to the increasing length of the N waveguides, there is a constant phase difference between the emitted lights of the N waveguides; but because the effective refractive index of the waveguides for light waves of different wavelengths is different, the phase difference formed by the light waves of different wavelengths after passing through the N waveguides different. Therefore, light of different wavelengths constructively interfere with each other in the beam combiner 57 at different positions. In the beam combiner, select the position where the light waves of the center wavelength of the signal light constructively interfere, and use a waveguide to connect the position to the exit coupler 58 to realize the signal light and the ambient light close to the signal light wavelength (that is, the signal light The light beam with the same center wavelength) is drawn from the beam combiner 57.

In some embodiments, the waveguide 55 in the waveguide dispersion element may be an optical fiber. The waveguide can transmit light beams in a curved path in a three-dimensional space. The beam splitter 56, the entrance coupler 54, the beam combiner 57, the exit coupler 58, and the waveguide 55 can be independent non-on-chip devices, can also be implemented by an on-chip optical circuit, or a combination of on-chip devices and discrete non-on-chip devices.

In the above-mentioned embodiments, the dispersive spectrum photosensitive component that can realize single-channel measurement is taken as an example. However, in other applications, it is often necessary for the lidar system to realize multi-channel measurement simultaneously to obtain large field of view/higher resolution. For measurement, in the following embodiments, an area-array dispersion-spectrum lidar containing an area-array dispersion-spectrum photosensitive component that can realize multi-channel measurement will be provided. The content of the above-mentioned dispersion spectrum photosensitive component is also applicable to the area array dispersion spectrum photosensitive component described in the following embodiments.

6 is a schematic diagram of the receiving end of a lidar system containing an area dispersion spectrum photosensitive component according to an embodiment of the present application. The receiving end includes an area dispersion spectrum photosensitive component 61 and a receiving optical component 62, wherein the receiving optical component 62 consists of at least one The lens or lens array is used to collect part of the laser beam (signal light) reflected by the object in the target space and other ambient light beams from the environment, such as the reflected beams from different fields of view (different channels) in the field of

view

631, 632, and 633, the reflected light beams are collected by the receiving optical group 62 and incident on the area array dispersion spectrum photosensitive component 61. The area array dispersion spectrum photosensitive component 61 includes an area array diaphragm 615, a collimating device 614, a filter 613, a dispersive device 612, and an area array detector 611 that are sequentially arranged along the incident light path.

The area array diaphragm 615 is provided with a plurality of holes or slits arranged in an area array, and each hole or slit is used to receive the light beam within the corresponding incident field of view of the corresponding receiving optical component 62, as shown schematically in FIG. 6 Three holes or slits are respectively used to receive incident light beams 631, 632, and 633 from three non-directional directions. For ease of illustration, only three channels are used as an example for illustration, but it should not be understood as being limited to three channels. The number and arrangement of the holes or slits on the area diaphragm 615 determine the field of view and the imaging resolution of the entire photosensitive assembly 61. Each light beam passing through the surface array diaphragm 615 is further incident on the collimating device 614; the collimating device 614 collimates the light beam passing through the diaphragm into a multi-channel parallel light beam, and the parallel light beam is then incident on the filter 613; The sheet 613 is a band-pass filter, which is used to filter the incident light beam, and only allows narrow-band wavelength light beams within a certain bandwidth with the center wavelength of the signal light as the center to pass through. The narrow-band wavelength light beam emitted by the filter 613 is incident on the dispersive device 612, and the dispersive device 612 disperses the incident narrow-band wavelength light beam in at least one direction according to the wavelength, so that light of different wavelengths irradiates different positions on the surface of the area array detector 611. For example, a plurality of light beams a, b, and c arranged along the wavelength are formed on the surface of the area array detector 611 (only three light beams are taken as an example for illustration, but there may be more light beams in fact). The area array detector 611 includes a plurality of pixels 616 (such as APD, SPAD, etc.) arranged in a two-dimensional array. Generally, the total number of pixels is greater than the total number of holes or slits on the area array diaphragm. The area array detector 611 is provided with a corresponding pixel group for each hole or slit, and each pixel group is spatially independently used to receive the light beams transmitted from the respective corresponding aperture holes or slits. Due to the effect of chromatic dispersion, light beams a, b, and c of different wavelengths will be incident on different positions in the pixel group. If the wavelength of the b beam is the same as the wavelength of the signal light, the signal generated by the pixel used to receive the b beam will be in the subsequent It is read out by the control and processor, and the flight time of the photon is calculated based on the read optical signal, and the distance to the target can be calculated based on the flight time. Since the ambient light of other bands is filtered out, the noise from the ambient light is greatly reduced, and finally the suppression effect on the ambient light is realized and the measurement accuracy is improved.

In some embodiments, the collimating device 614 can be one of at least one lens, a microlens array, a mirror (including a flat mirror, a curved mirror, a reflective prism, and other types of mirrors), a surface array waveguide transmission element, or one of A variety of combinations.

In some embodiments, the dispersive device 612 includes a dispersive element, where the dispersive element may be one or a combination of a prism, a grating, and a dispersive hologram. The dispersive device 612 may further include a converging lens, which may be composed of one or more combinations of at least one lens, a microlens array, and a mirror.

In some embodiments, the dispersive device 612 may also be a surface array waveguide dispersion element, which is composed of a plurality of waveguide dispersion elements as shown in FIG. 5a and FIG. The holes or slits on the stop correspond to each other, and they are used to receive the light beams transmitted from the corresponding holes or slits.

For the area array dispersion spectrum lidar, in order to achieve better performance of the lidar system, the alignment device and the dispersion device need to be considered as a whole to design the corresponding area array dispersion spectrum lidar receiving end. The following will be based on this application. Idea proposes several receiver embodiments.

Fig. 7 is a schematic diagram of a receiving end of an area array dispersion spectrum lidar according to an embodiment of the present application. The receiving end includes an area dispersion spectrum photosensitive component 71 and a receiving optical component 72; wherein, the receiving optical component 72 is composed of at least one lens or lens array for collecting part of the laser beam (signal light) reflected by the object in the target space and Other ambient light beams from the environment, such as reflected

beams

731, 732, and 733 from different field of view areas (different channels) in the field of view. The reflected beams are collected by the receiving optics 72 and enter the area array dispersion spectrum photosensitive component 71 . The dispersive spectrum photosensitive component 71 includes an area diaphragm 715, a first microlens array 714, a filter 713, a dispersive device 712, and an area detector 711.

The area array diaphragm 715 is provided with a plurality of holes or slits arranged in an area array, and each hole or slit is used to receive the light beam in the corresponding incident field of view (channel) of the corresponding receiving optical component 72. Each light beam passing through the area aperture 715 is further incident on the first microlens array 714; each microlens in the first microlens array 714 corresponds to the holes or slits in the area aperture 715 one by one, and respectively transmits the light The beam of the stop is collimated into a parallel beam, and the parallel beam is then incident on the filter 713; the filter 713 allows the narrow-band wavelength light beam within a certain bandwidth with the center wavelength of the signal light as the center to pass through, and the narrow-band wavelength transmitted The light beam is then incident on the dispersive device 712. The dispersive device 712 includes a dispersive element 717 and a second microlens array 716. The dispersive element 717 can be one or a combination of prisms, gratings, and dispersive holograms, and is used to transmit the incident narrow-band wavelength light beams along at least one wavelength according to the wavelength. Dispersion in the direction; each microlens in the second microlens array 716 corresponds to each microlens in the first microlens array 714 or the hole or slit in the area diaphragm 715, which is used to transfer the dispersion element 717 The light beams are converged/focused to be incident on the corresponding pixels on the area array detector 711. Due to the dispersive effect of the dispersive element 717, the light beams from the same diaphragm will be incident on different pixels according to different wavelengths, so that they are spatially separated, and finally receive the pixel signal of the light beam with the same wavelength as the signal light. It is subsequently read by the control and processor.

Fig. 8 is a schematic diagram of a receiving end of an area array dispersion spectrum lidar according to another embodiment of the present application. The receiving end includes an area dispersion spectrum photosensitive component 81 and a receiving optical component 82; wherein, the receiving optical component 82 is composed of at least one lens or lens array for collecting part of the laser beam (signal light) reflected by an object in the target space, and Other ambient light beams in the environment, such as reflected beams from different field of view areas (different channels) in the field of view. For ease of illustration, only channel 831 is used as an example for illustration in this embodiment, and the reflected beams are received by the optical group 82 It is collected and incident on the area array dispersion spectrum photosensitive component 81. The dispersive spectrum photosensitive component 81 includes an area diaphragm 815, a first microlens array 814, a filter 813, a dispersive device 812, and an area detector 811.

The difference from the embodiment shown in FIG. 7 is that the dispersive device 812 in the embodiment shown in FIG. 8 includes a second microlens array 819, a first lens 818, a dispersive element 817, and a second lens 816 arranged in sequence along the optical path. Wherein, each microlens in the second microlens array 819 corresponds to each microlens in the first microlens array 814 or the holes or slits in the area diaphragm 815 in a one-to-one correspondence, and is used to receive and converge data from the first microlens array. The collimated light beam after collimation by the lens array 814; the first lens 818 receives the converged light beam from the second microlens array 819 and collimates and expands the beam. The expanded parallel beam is then incident on the dispersive element 817, After dispersion, it is incident on the second lens 816, and the second lens 816 is used to converge or focus the dispersed light beam to be incident on the corresponding pixel on the area array detector 811. Due to the dispersion effect of the dispersive element 817, the light beams of different wavelengths enter the second lens 816 in different directions, so that the light beams from the same diaphragm are incident on different pixels according to different wavelengths, so that they are separated in space. , The pixel signal that finally receives the light beam with the same wavelength as the signal light is subsequently controlled and read out by the processor. Wherein, the first lens 818 and the second lens 816 may be a single lens or a lens group composed of multiple lenses.

Fig. 9 is a schematic diagram of a receiving end of an area-array dispersion spectrum lidar according to another embodiment of the present application. The receiving end includes an area dispersion spectrum photosensitive component 91 and a receiving optical component 92. Among them, the receiving optical component 92 is composed of at least one lens or lens array, which is used to collect part of the laser beam (signal light) reflected by the object in the target space and other ambient light beams from the environment, such as from different views in the field of view. The reflected

light beams

931, 932, and 933 in the field area (different channels) are collected by the receiving optical group 92 and incident on the area array dispersion spectrum photosensitive component 91. The dispersive spectrum photosensitive component 91 includes an area diaphragm 915, a first microlens array 914, a filter 913, a dispersive device 912, and an area detector 911.

The difference from the embodiment shown in FIGS. 7 and 8 is that the dispersive device 912 in the embodiment of FIG. 9 includes a planar array waveguide dispersive element 912 composed of a plurality of waveguide dispersive elements 916, and each of the waveguide dispersive elements 916 is used for receiving The light beams from the corresponding apertures or slits, and selectively output light beams consistent with the center wavelength of the signal light, are incident on the corresponding pixels of the area array detector 911. Generally, each waveguide dispersion element 916 on the surface array waveguide dispersion element 912 corresponds to each microlens on the first microlens array 914 or each hole or slit on the aperture 915 in a one-to-one correspondence, including the number and/or arrangement. One-to-one correspondence.

In the embodiments shown in Figs. 7-9, the collimating devices are all microlens arrays. In fact, other devices, such as lenses (lens groups), waveguide transmission elements, etc., can also be used. Two specific embodiments will be exemplarily introduced below.

Referring to FIG. 10, FIG. 10 is a schematic diagram of a receiving end of an area array dispersion spectrum lidar according to another embodiment of the present application. The receiving end includes an area dispersion spectrum photosensitive component 101 and a receiving optical component 102. Among them, the dispersive spectrum photosensitive component 101 includes an area array diaphragm 1015, a first lens 1014, a filter 1013, a dispersive device 1012, and an area array detector 1011.

The area array diaphragm 1015 is provided with a plurality of holes or slits arranged in an area array, and each hole or slit is used to receive the light beam in the corresponding incident field angle of the receiving optical component 102 corresponding thereto. Each light beam passing through the area aperture 1015 is further incident on the first lens 1014, and the first lens 1014 collimates the light beam passing through the diaphragm into a parallel light beam, and the parallel light beam is then incident on the filter 1013; the filter 1013 The narrow-band wavelength light beam within a certain bandwidth with the center wavelength of the signal light as the center is transmitted, and the transmitted narrow-band wavelength light beam is then incident on the dispersive device 1012. The dispersive device 1012 includes a dispersive element 1017 and a second lens 1016. The dispersive element 1017 is used to disperse the incident narrow-band wavelength light beam in at least one direction according to the wavelength; the second lens 1016 cooperates with the first lens 1014 to disperse the incident parallel light beam The convergence/focusing is performed to be incident on the corresponding pixels on the area array detector 1011. Due to the chromatic dispersion effect of the dispersive element 1017, the light beams from the same diaphragm will be incident on different pixels according to different wavelengths, so that they are separated in space, and finally receive the pixel signal of the light beam with the same wavelength as the signal light. It is subsequently read by the control and processor. Wherein, the first lens 1014 and the second lens 1016 may be a single lens or a lens group composed of multiple lenses.

Referring to FIG. 11, FIG. 11 is a schematic diagram of a receiving end of an area array dispersion spectrum lidar according to another embodiment of the present application. The receiving end includes an area dispersion spectrum photosensitive component 111 and a receiving optical assembly 112; wherein, the dispersion spectrum photosensitive component 111 includes an area array diaphragm 1115, a collimating device 1114, a filter 1113, a dispersive device 1112, and an area detector 1111.

The area array diaphragm 1115 is provided with a plurality of holes or slits arranged in an area array, and each hole or slit is used to receive the light beam within the corresponding incident field angle of the receiving optical component 112 corresponding thereto. Each light beam passing through the surface array aperture 1115 is further incident on the collimating device 1114. The collimating device 1114 includes a surface array waveguide transmission element composed of a plurality of waveguide transmission elements 117, and each of the waveguide transmission elements 117 is used to receive from Corresponding to the light beam of the aperture or slit, and the light beam is emitted after being transmitted and collimated. Generally, each waveguide transmission element 117 on the area array waveguide transmission element corresponds to each hole or slit on the aperture 1115 in a one-to-one correspondence, and the one-to-one correspondence includes a one-to-one correspondence in number and/or arrangement. In some embodiments, the collimating device 1114 further includes a lens provided at the entrance coupler and/or exit coupler of each waveguide transmission element, such as the first microlens array 116 and/or the second microlens array 118, and the microlens array Each microlens in the corresponding one-to-one correspondence with each waveguide transmission element.

The parallel beams collimated by the collimating device 1114 are then incident on the filter 1113; the filter 1113 allows the narrow-band wavelength beams within a certain bandwidth with the center wavelength of the signal light as the center to pass through, and the narrow-band wavelength beams that pass through Then it is incident on the dispersive device 1112. The dispersive device 1112 includes a dispersive element 115 and a third microlens array 114. The dispersive element 115 is used to disperse the incident narrow-band wavelength light beam in at least one direction according to the wavelength; each microlens in the third microlens array 114 and the surface array waveguide Each waveguide transmission element 117 in the transmission element and/or each hole or slit on the aperture 1115 corresponds to each other, and is used to converge/focus the light beam from the dispersive element 115 to be incident on the corresponding pixel on the area array detector 1111 .

In the embodiment shown in FIG. 9, the dispersion element in the dispersive spectrum photosensitive component adopts the surface array waveguide dispersion element. In the embodiment shown in FIG. 11, the collimation device adopts the surface array waveguide transmission element. The curved path in the space transmits the light beam, so the multiple exit couplers in the area waveguide dispersion (transmission) element can be rearranged or adjusted in space, and can be rearranged relative to the spatial arrangement of the multiple entrance couplers. Realize the arrangement and/or direction of the outgoing beams required by the system. For example, due to the arrangement of pixels on the area array detector, in order to more evenly introduce the beams in the respective diaphragm apertures to the corresponding pixels, the outgoing beams can be The arrangement and/or direction of the couplers are re-adjusted to realize the flexible configuration of the mapping relationship between the diaphragm aperture and the detector pixels.

It is understandable that any device with the same function as the collimating device can be used in the dispersive spectrum photosensitive component to replace the collimating device, and any device with the same function as the dispersing element can also be used to replace the dispersing element, and the collimating device is compatible with the collimating device. The combination of dispersive elements is not limited to the above-mentioned embodiments. Any combination based on the idea of the present application and capable of achieving similar functions belongs to the protection scope of the present application.

The emission end of the dispersive spectrum lidar will be described later. With reference to Fig. 1, the emission end 12 includes a light source 13 and a transmitting optical component 14 for emitting at least one channel of laser beams (signal light beams) into space for different applications. If necessary, the transmitter can be configured in different forms.

In some embodiments, the emitting end is used to emit a spot light beam, and the emitted spot light beam can be a single spot or multiple spots. In order to obtain point cloud data with high spatial resolution within the measurement field of view, in some embodiments Scanning elements can also be added to the emission optical assembly 14; in addition, the emission optical assembly 14 also includes beam shaping elements, such as lenses, mirrors, etc., used to shape the divergent light beam emitted by the light source into a single-point or multi-point spot and Shine on the target. It is understandable that when the transmitting end emits only one spot light spot, the aperture in the corresponding receiving end only needs one light-passing hole, and the light-passing hole is located on the optical axis of the receiving system; when the reflecting end emits multiple spots In the case of light spots, the diaphragm has multiple light-passing holes, and each light-passing hole forms a one-to-one correspondence with each light spot emitted. For multi-point light spots, they can be arranged along a line, or two-dimensionally arranged along the x-direction and the y-direction.

In some embodiments, the emitting end is used to emit a single-line spot or a multi-line spot. Also in order to obtain point cloud data with high spatial resolution within the measurement field of view, in some embodiments, scanning may be added to the emitting optical assembly 14. element. In addition, the transmitting optical assembly 14 also includes beam shaping elements, such as lenses, mirrors, etc., for shaping the divergent light beam emitted by the light source into a single-line or multi-line spot and irradiating the target. Generally, a linear spot has a small beam divergence angle in one direction, such as 0.05°～0.15°, and a spot with a divergence angle of several tens of degrees in the other direction. When the emitted light spot is a multi-line light spot, the lines are parallel to each other.

In the spot and line spot embodiments, the emitting end light source can be a single-point edge-emitting laser, a single-point vertical cavity surface laser (VCSEL), a emitting laser array composed of multiple edge-emitting lasers, a VCSEL array, and a partitioned laser. Controlled VCSEL, etc. The beam shaping device is composed of one or a combination of lenses, microlens arrays, Metasurface devices, dichroic prisms, and mirrors. The scanning element can be composed of MEMS micromirror, rotating prism, rotating prism pair, mechanical galvanometer, OPA scanning device, etc.

In some embodiments, the emitting end may directly emit multiple spots without scanning elements. The emitting end includes an area array light source composed of multiple sub-light sources and an emitting optical component. The divergent light beams emitted by the sub-light sources are included in the emitting optical component. The beam shaping element of the beam shaping element is formed into a point spot or a line spot to be emitted into the space. The processing and controller can light up multiple sub-sources in the area array light source, and only gate and receive when the sub-light source in the corresponding area is lit. Corresponding pixels on the end detector to achieve scanning measurement along at least one direction. The light source can be multiple edge-emitting lasers that can be sequentially lit, multiple VCSEL lasers that can be sequentially lit, VCSEL area array lasers that can be lit up in sections, and the like.

It is understandable that when the position or hardware in the system of the present application is changed to the corresponding structure or components or simply replaced to meet the needs, the essence of the system still adopts the dispersive spectrum lidar of the present application, so it should be regarded as the protection of the present application. Scope.

It is understandable that the above content is a further detailed description of the application in conjunction with specific/preferred implementations, and it cannot be considered that the specific implementation of the application is limited to these descriptions. For those of ordinary skill in the technical field to which this application belongs, without departing from the concept of this application, they can also make several substitutions or modifications to the described implementations, and these substitutions or modifications should be regarded as It belongs to the protection scope of this application. In the description of this specification, reference to the description of the terms "one embodiment", "some embodiments", "preferred embodiment", "examples", "specific examples", or "some examples" etc. means to incorporate the implementation The specific features, structures, materials or characteristics described by the examples or examples are included in at least one embodiment or example of the present application.

In this specification, the schematic representations of the above-mentioned terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples and the features of the different embodiments or examples described in this specification without contradicting each other. Although the embodiments of the present application and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope defined by the appended claims.

In addition, the scope of the present application is not intended to be limited to the specific embodiments of the processes, machines, manufacturing, material composition, means, methods, and steps described in the specification. A person of ordinary skill in the art will easily understand that the above-mentioned disclosures, processes, machines, processes, machines, processes, machines, and machines that currently exist or will be developed later that perform substantially the same functions as the corresponding embodiments described herein or obtain substantially the same results as the embodiments described herein can be used. Manufacturing, material composition, means, method, or step. Therefore, the appended claims intend to include these processes, machines, manufacturing, material compositions, means, methods, or steps within their scope.

Claims

A dispersive spectrum lidar system is characterized in that it comprises:

The transmitting end is configured to emit a signal light beam;

The receiving end includes a receiving optical component and a dispersive spectrum photosensitive component; wherein the receiving optical component is used to receive at least part of the signal light beam and part of the ambient light beam reflected by the target and incident into the dispersive spectrum photosensitive component, so The dispersive spectrum photosensitive component disperses the incident light beam to distinguish light beams of different wavelengths spatially;

The control and processor is used to control the dispersive spectrum photosensitive component to filter out the incident light beam signal having the same wavelength as the signal light beam, and calculate the flight time of the photon based on the incident light beam signal.
The dispersive spectrum lidar system according to claim 1, wherein the dispersive spectrum photosensitive component includes a dispersive device and a photosensitive detector; wherein the dispersive device disperses the incident light beam, and varies according to wavelength The angle is emitted so that light beams of different wavelengths are incident on different spatial positions of the photosensitive detector.
The dispersive spectrum lidar system of claim 1, wherein the transmitting end includes a light source and a transmitting optical component, and the light source is used to emit a signal light beam and is modulated by the transmitting optical component to the target. emission.
The dispersive spectrum lidar system of claim 1, wherein the signal light beam includes one of a spot beam, a line beam, and a flood beam.
The dispersive spectrum lidar system according to claim 1, wherein the transmitting end includes at least one transmitting channel, and the receiving optical component includes at least one receiving channel; wherein, the transmitting channel and the receiving channel One-to-one correspondence.
The dispersive spectrum lidar system according to claim 1, wherein the transmitting end and the receiving end are arranged in a coaxial form.
The dispersive spectrum lidar system according to claim 1, wherein the transmitting end and the receiving end are arranged in an off-axis form.
The dispersive spectrum lidar system of claim 1, wherein the transmitting end and the receiving end are installed on the same substrate.
The dispersive spectrum lidar system of claim 1, further comprising a rotating platform for placing the transmitting end and the receiving end, and rotating under the control of the control and processor to achieve scanning.
A measurement method using a dispersive spectrum lidar system is characterized in that it comprises the following steps:

Emit the signal light beam;

Receiving at least part of the signal light beam and part of the ambient light beam reflected back by the target;

Disperse the received incident light beam to distinguish light beams of different wavelengths spatially;

The incident light beam signal having the same wavelength as the signal light beam is filtered out, and the flight time of the photon is calculated based on the incident light beam signal.