A dispersion spectroscopic lidar system and measurement method

Abstract

The present invention discloses a dispersion spectrum lidar system, comprising: a transmitting end configured to emit a signal light beam; a receiving end including a receiving optical component and a dispersion spectrum photosensitive component, wherein the receiving optical component is used to receive at least part of the signal light beam reflected by the target and part of the ambient light beam and incident on the dispersion spectrum photosensitive component, and the dispersion spectrum photosensitive component disperses the incident beam to spatially distinguish beams of different wavelengths; a control and processor is used to control the dispersion spectrum photosensitive component to screen out the incident beam signal consistent with the wavelength of the signal light beam, and calculate the flight time of photons based on the incident beam signal. By means of dispersion, the screening of the signal light wavelength is realized, thereby improving the signal-to-noise ratio and measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical fields of optical sensors and lidar, and particularly to a dispersive spectroscopy lidar system and a measurement method. Background Art

[0002] Lidar is an active three-dimensional measurement technology. It emits a laser beam into space through a laser emission end, and then after receiving the laser beam reflected by an object through a receiving end, it processes the received optical signal to obtain the flight time of the laser beam in space. According to the relationship between distance, photon flight time, and the speed of light, the distance and azimuth information of the target can be calculated. Ambient light interference is a common problem faced by current lidar systems. That is, when lidar works under strong outdoor light, it is often interfered by solar ambient light, resulting in a certain degree of decline in measurement distance and measurement accuracy.

[0003] To solve the problem of ambient light interference, in existing solutions, a near-infrared laser emitter with relatively low solar spectral irradiance is often selected, and further ambient light filtering is performed by cooperating with a narrowband filter near this wavelength band at the receiving end. However, considering practical problems in engineering, such as manufacturing tolerances of the central wavelength of the laser emitter, manufacturing tolerances of the central transmission wavelength of the filter, and drift of the central wavelength of the laser emitter with temperature, the full width at half maximum of the spectral transmittance of the actually used filter is much larger than the full width at half maximum of the laser wavelength. Therefore, the effect of ambient light filtering is very limited, resulting in low signal-to-noise ratio and measurement accuracy.

[0004] The disclosure of the above background art content is only used to assist in understanding the inventive concept and technical solution of the present invention, and it does not necessarily belong to the prior art of this patent application. Without clear evidence indicating that the above content was publicly available on the filing date of this patent application, the above background art should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0005] The purpose of the present invention is to provide a dispersive spectroscopy lidar system and a measurement method to solve at least one of the above background art problems.

[0006] To achieve the above object, the technical solution of the embodiment of the present invention is realized as follows:

[0007] A dispersion spectral lidar system, comprising: a transmitting end configured to transmit a signal light beam; a receiving end including a receiving optical component and a dispersion spectral photosensitive component; wherein, the receiving optical component is used to receive at least part of the signal light beam reflected back by the target and part of the ambient light beam and incident on the dispersion spectral photosensitive component, and the dispersion spectral photosensitive component disperses the incident beam to spatially distinguish light beams of different wavelengths; a control and processor is used to control the dispersion spectral photosensitive component to screen out the incident beam signal consistent with the wavelength of the signal light beam, and calculate the flight time of photons based on the incident beam signal.

[0008] In some embodiments, the dispersion spectral photosensitive component includes a dispersion device and a photosensitive detector; wherein, the dispersion device disperses the incident beam and exits at different angles according to the wavelength, so that light beams of different wavelengths are incident on different spatial positions of the photosensitive detector.

[0009] In some embodiments, the transmitting end includes a light source and a transmitting optical component, and the light source is used to transmit a signal light beam and transmit it to the target after being modulated by the transmitting optical component.

[0010] In some embodiments, the signal light beam includes one of a speckle beam, a line beam, and a floodlight beam.

[0011] In some embodiments, the transmitting end includes at least one transmitting channel, and the receiving optical component includes at least one receiving channel; wherein, the transmitting channels and the receiving channels correspond one by one.

[0012] In some embodiments, the transmitting end and the receiving end are arranged in a coaxial form.

[0013] In some embodiments, the transmitting end and the receiving end are arranged in an off-axis form.

[0014] In some embodiments, the transmitting end and the receiving end are mounted on the same substrate.

[0015] In some embodiments, 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 achieve scanning.

[0016] Another technical solution of the embodiment of the present invention is:

[0017] A method for measurement using a dispersion spectral lidar system, comprising the following steps:

[0018] Transmit a signal light beam;

[0019] Receive at least part of the signal light beam reflected back by the target and part of the ambient light beam;

[0020] Disperse the received incident light beam to spatially distinguish light beams of different wavelengths;

[0021] Select the incident light beam signal that is consistent with the wavelength of the signal light beam, and calculate the flight time of photons based on the incident light beam signal.

[0022] The beneficial effects of the technical solution of the present invention are:

[0023] In view of the problem of ambient light interference in lidar, the present invention proposes a dispersion spectral lidar system and a measurement method based on dispersion, which can more effectively reduce the influence of ambient light and improve the detection range and accuracy of lidar. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 is a schematic diagram of the composition of a dispersion spectral lidar according to an embodiment of the present invention;

[0026] Figure 2 is a schematic diagram of a mechanical scanning dispersion spectral lidar system according to an embodiment of the present invention;

[0027] Figure 3 is a schematic diagram of a non-mechanical scanning dispersion spectral lidar system according to an embodiment of the present invention;

[0028] Figure 4 is a schematic diagram of the composition of the receiving end of a dispersion spectral lidar according to an embodiment of the present invention;

[0029] Figure 5a is a schematic diagram of a waveguide transmission element according to an embodiment of the present invention;

[0030] Figure 5b is a schematic diagram of a waveguide dispersion element according to an embodiment of the present invention;

[0031] Figure 6 is a schematic diagram of the receiving end of a lidar system including a planar array dispersion spectral photosensitive component according to an embodiment of the present invention;

[0032] Figure 7 is a schematic diagram of the receiving end of a planar array dispersion spectral lidar according to an embodiment of the present invention;

[0033] Figure 8 It is a schematic diagram of the receiving end of a planar array dispersive spectral lidar according to another embodiment of the present invention;

[0034] Figure 9 It is a schematic diagram of the receiving end of a planar array dispersive spectral lidar according to yet another embodiment of the present invention;

[0035] Figure 10 It is a schematic diagram of the receiving end of a planar array dispersive spectral lidar according to yet another embodiment of the present invention;

[0036] Figure 11 It is a schematic diagram of the receiving end of a planar array dispersive spectral lidar according to yet another embodiment of the present invention. Detailed implementation manners

[0037] In order to make the technical problems, technical solutions and beneficial effects to be solved by the embodiments of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0038] It should be noted that when an element is referred to as "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 "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 for a fixing function or for an electrical connection function.

[0039] It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "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 present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0040] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0041] Figure 1The figure shows a schematic diagram of a dispersion spectrum lidar system according to an embodiment of the present invention. The system 10 includes a transmitting end 12, a receiving end 15, and a control and processor 11; wherein, the transmitting end 12 includes a light source 13 and a transmitting optical component 14; the receiving end 15 includes a dispersion spectrum photosensitive component 16 and a receiving optical component 17. The transmitting end 12 emits a laser beam (also called: signal light beam) within a specific wavelength range through the light source 13, such as a laser beam with a wavelength near 960 nm or 1550 nm. This laser beam group is modulated by the transmitting optical component 14 and then emitted towards the target space; the receiving optical component 17 in the receiving end 15 is used to collect at least part of the laser beam reflected by an object in the target space and other beams from ambient light, and make it incident on the dispersion spectrum photosensitive component 16. The dispersion spectrum photosensitive component 16 disperses the received beam to distinguish the incident beam in space according to different wavelengths; the spatial positions where the beams of different wavelengths fall are different. The control and processor 11 controls the dispersion spectrum photosensitive component 16 and filters out the incident beam signal that is only consistent with the central wavelength of the signal beam emitted by the transmitting end 12 (specifically, a narrowband wavelength beam signal within a very small interval centered on the central wavelength of the transmitted signal beam. In theory, this interval range should include most of the signal light beams and very few ambient light beams), and calculates the flight time of photons based on this incident beam signal. Further, the distance D of the target is calculated based on this flight time, that is:

[0042] D = c·t / 2 (1)

[0043] where c is the speed of light and t is the flight time.

[0044] Preferably, the dispersion spectrum photosensitive component 16 includes a dispersion device and a photosensitive detector. The dispersion device disperses the incident beam and emits it at different angles according to the wavelength, so that the beams of different wavelengths are incident on different spatial positions of the photosensitive detector, which is convenient for subsequent screening. Specific embodiments of the dispersion spectrum photosensitive component 16 will be introduced in detail later.

[0045] The dispersion function of the dispersion spectrum photosensitive component enables the incident beam to be distinguished in space according to the wavelength, so as to filter out the signal light. Compared with filtering only through a filter, the dispersion can very accurately locate the signal light. The bandwidth of the filtered narrowband beam is smaller than that of the filter, and at the same time, most of the ambient light noise can be filtered out, thereby greatly improving the accuracy and signal-to-noise ratio of the lidar system.

[0046] According to the requirements of different lidars for functions, performance, etc., the system can be designed in different styles. For example, for a long-range lidar, the transmitting end 12 will emit a high-power laser beam, which is pre-modulated into shapes such as spots and lines, and the field of view covered by the entire laser beam is relatively small; while for a short-range 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 floodlight, spot, line, etc. Similarly, the receiving end 15 is also specially designed to correspond to the transmitting end. Several specific embodiments will be introduced in detail later.

[0047] In one embodiment, the transmitting end 12 is used to emit a single laser beam 18 into space, and the laser beam 18 has a certain cross-sectional shape 20, such as circular spot shape, elliptical shape, linear shape, etc. Correspondingly, the receiving beam assembly 17 in the receiving end 15 is used to collect the light beams 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 certain design, so that the receiving end can collect the laser beams reflected by the objects in the target space, and then further calculate the flight time. Generally, the field of view 19 is larger than the divergence angle of the laser beam 18. For the convenience of description, in the embodiments of the present invention, a laser beam and the field of view of the receiving end corresponding to the laser beam are called a channel, and the transmitting channels of the transmitting end and the receiving channels of the receiving end correspond one by one, so as to realize the distance measurement of the target object. The channel can be any form of channel such as a point channel, a line channel, a coded channel, etc.

[0048] Figure 1 Only a single channel is schematically drawn in the figure. In other embodiments, the system 10 can achieve distance measurement with a larger field of view by scanning single channels or multiple channels. For example, in one embodiment, beam scanning devices such as MEMS galvanometers and mechanical rotating mirrors are arranged in the transmitting optical assembly 14 and / or the receiving optical assembly 17 to achieve beam scanning, so as to achieve multi-channel measurement. Of course, an additional beam scanning assembly can also be added to achieve this. In one embodiment, the transmitting end 12 can simultaneously emit multi-channel laser beams. Correspondingly, the receiving end 15 also has a plurality of receiving channels corresponding one by one to the transmitting channels of the transmitting end 12, so that multi-channel (such as dot matrix, line matrix, etc.) scanning of the target can be realized simultaneously.

[0049] In some embodiments, the transmitting end 12 and the receiving end 15 are arranged in a coaxial form. For example, this can be achieved by adding optical elements such as a semi-transparent and semi-reflective mirror with reflection and transmission functions, or a transmissive and reflective mirror with a hole in the middle of the mirror. 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 arranged in an off-axis form. Compared with the coaxial form, the off-axis form has lower requirements for hardware and is convenient for assembly. The disadvantage is that the problem of parallax needs to be considered. When the target is at different distances, there will be a deviation between the transmitting channel and the receiving channel due to parallax. It can be understood that when the measured distance is much larger than the baseline distance between the transmitting end and the receiving end, the problem of parallax can also be ignored. When the measured distance is relatively close, the problem of parallax can be solved by calibration, spot positioning and other methods.

[0050] 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 simultaneously fabricated on the same semiconductor substrate through semiconductor processes, and then optical devices, electronic components, etc. are further installed on the semiconductor substrate to form the transmitting end and the receiving end.

[0051] In some embodiments, the dispersion spectral lidar is configured as a lidar system in a mechanical scanning form, as Figure 2 shown. This lidar system in a mechanical scanning form includes a transmitting end 201, a receiving end 202, and a rotating platform 203 for placing the transmitting end and 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 achieve scanning of a large field of view angle (such as 360 degrees).

[0052] In some embodiments, the dispersion spectral lidar is configured as a lidar system in a non-mechanical scanning form, as Figure 3 shown. The transmitting end 12 and the receiving end 15 of this lidar system in a non-mechanical scanning form are configured to have a common field of view 31. Generally, the transmitting end 12 is used to emit laser beams of multiple channels to illuminate a target within the common field of view angle, and the receiving end 15 is used to collect the laser beams reflected back from within the common field of view angle.

[0053] Based on the dispersion spectral lidar system described in the above embodiments, the embodiment of the present invention also provides a method for measurement based on the above dispersion spectral lidar. The method includes the following steps:

[0054] First, emit a signal light beam;

[0055] Second, receive at least part of the signal light beam reflected back by the target and part of the ambient light beam;

[0056] Again, the received incident light beam is dispersed to spatially distinguish light beams of different wavelengths;

[0057] Finally, the incident light beam signal that is consistent with the wavelength of the signal light beam is selected, and the flight time of photons is calculated based on the incident light beam signal.

[0058] The above steps are specifically implemented by Figures 1-3 the dispersion spectral lidar system in the illustrated embodiment. For the detailed method steps, reference can be made to Figures 1-3 the description in the illustrated embodiment, which will not be elaborated herein.

[0059] Figure 4 FIG. is a schematic diagram of the composition of the receiving end of a dispersion spectral lidar according to an embodiment of the present invention. The receiving end includes a dispersion spectral 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, and is used to receive a part of the laser beam (signal light) reflected back by an object 46 in the target space and other ambient light beams from the environment. In this embodiment, a bar-shaped laser beam emitted by the transmitting end will be taken as an example for illustration. It can be understood that the present invention is not limited to bar-shaped beams. The object 46 will reflect a bar-shaped beam 47 (including signal light and ambient light), which is collected by the receiving optical group 42 and incident on the dispersion spectral photosensitive component 41.

[0060] The dispersion spectral photosensitive component 41 includes a diaphragm 415, a collimating device 414, a filter 413, a dispersive device 412, and an array detector 411 arranged in sequence along the incident optical path; the beam 47 reflected back by the object 46 converges to the plane of the diaphragm 415 after passing through the receiving optical component 42; the diaphragm limits the field of view angle of the receiving optical component 42, and only the reflected beam received within this field of view angle can pass through the diaphragm and further be incident on the collimating device 414; the collimating device 414 collimates the reflected beam passing through the diaphragm into a parallel beam, and this parallel beam is then incident on the filter 413; the filter 413 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 range centered on the central wavelength of the signal light to pass through; generally, the passband wavelength of the filter 413 is set to be centered on the central wavelength of the signal light, and the full width at half maximum of the transmittance is usually dozens of nanometers (only as an example). However, since 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 within dozens of nanometers near the central wavelength of the signal light will pass through the filter.

[0061] The narrow-band wavelength light beam emitted from the filter 413 is incident on the dispersion device 412. The dispersion device 412 disperses the incident narrow-band wavelength light beam in one direction according to the wavelength, so that light of different wavelengths irradiates different positions on the surface of the array detector 411. For example, a plurality of light beams 43, 44, 45 arranged along the wavelength are formed on the surface of the array detector 411. Thus, some pixels of the array detector 411 (such as 44) are only irradiated 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 with the signal light in space, such as 43, 45. Subsequently, the control and processor can only read out the signals in the corresponding pixels on the array detector 411 in the signal light band, and calculate the flight time of the photons based on the read optical signal. Further, the distance to the target can be calculated based on the flight time. By spatially distinguishing through dispersion, the ambient light in the narrow-band wavelength light beam from the filter can be further filtered out. Through the reasonable design of the dispersion device and the design of the array detector, theoretically, only the light beams within the signal light bandwidth can be selected. Therefore, compared with the filtering effect of only the filter, the noise from the ambient light can be further greatly reduced, and finally the suppression effect on the ambient light is achieved, improving the measurement accuracy and signal-to-noise ratio.

[0062] The aperture 415 is generally arranged on the focal plane of the receiving optical assembly 42, and at least one hole or one slit is included on the aperture 415. The arrangement form and quantity of the set holes or slits determine the optical performance such as the field of view angle and resolution of the dispersion spectrum photosensitive assembly 41; generally, the aperture is set in a reasonable form according to the overall performance requirements of the lidar system. For example, for a single-channel lidar, if the emitting end emits a line light beam, the aperture can only include a single linear hole, that is, a single-slit aperture; if the emitting end emits a point light beam, the aperture can only include a single round hole, that is, a single-hole aperture. When the emitting end emits a planar light beam, the aperture can include a plurality of slits or a plurality of holes arranged in an array, that is, a multi-slit aperture or a multi-hole aperture. Thus, array optical signals can be synchronously received to obtain depth measurement information of the array, which will be described in detail later.

[0063] The position of the aperture through-hole or slit in the plane of the aperture can be fixed or movable. When the position of the aperture through-hole or slit is movable, the movement amount of the through-hole or slit position is controlled by the control and processor. The movable aperture includes but is not limited to being realized by an MEMS mechanism, a liquid crystal device, etc. In one embodiment, the opening and closing of the aperture through-hole or slit can also be controlled by the control and processor. For a multi-hole or multi-slit aperture, the holes or slits on the aperture can be arranged in a one-dimensional or two-dimensional arrangement form as needed, such as a regular two-dimensional array, an irregular two-dimensional array, etc.

[0064] In some embodiments, the array detector 411 is an array-type optical receiving device composed of multiple pixels. Typically, there are APD (avalanche photodiode) arrays and SPAD (single-photon avalanche diode) arrays. 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 the direction consistent with the dispersion direction.

[0065] In some embodiments, the collimating device can be composed of one or a combination of at least one lens, microlens array, mirror (including various types of mirrors such as plane mirrors, curved mirrors, and reflecting prisms), and waveguide transmission elements.

[0066] For the waveguide transmission element, reference can be made to Figure 5a as shown Figure 5a is a schematic diagram of a waveguide transmission element according to an embodiment of the present invention. The waveguide transmission element is composed of an input coupler 51, a waveguide 52, and an output coupler 53, and is used to transmit the incident light beam in three-dimensional space and emit it 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, it can control the spatial position and emission direction of the output collimated light beam according to needs, which will be described later. The waveguide 52 in the waveguide transmission element can be an optical fiber. The waveguide can transmit the light beam along a curved path in three-dimensional space. The input coupler 51, the output coupler 53, and the waveguide 52 can be independent off-chip devices, or can be realized by on-chip optical paths, or can be a combination of on-chip devices and discrete off-chip devices.

[0067] In some embodiments, the filter 413 can be placed at other positions in the optical path. For example, it can be placed outside the diaphragm 415 (including being placed between the receiving optical component 42 and the target object 46, or between the diaphragm 415 and the receiving optical component 42), or between the diaphragm 415 and the collimating device 414, or between the collimating device 414 and the dispersion device 412, or between the dispersion device 412 and the array detector 411; preferably, the filter 413 is placed between the collimating device 414 and the dispersion device 412.

[0068] The dispersion device 412 includes at least one dispersion element, such as a combination of one or more of a prism, a grating, and a dispersion hologram, which can form an output light beam with different output angles for the incident light beam according to different wavelengths, thereby realizing the dispersion effect of the light beam. Among them, the dispersion hologram is a holographic device that simultaneously has a dispersion function and a focusing function (or a diverging function). In some embodiments, in addition to the dispersion element, the dispersion device 412 further includes a combination of one or more of a lens, a lens group, a microlens array, and a mirror.

[0069] In some embodiments, the dispersion element can also be a waveguide dispersion element, such asFigure 5b As shown. The waveguide dispersion element includes an input coupler 54, a beam splitter 56, a combiner 57, an output coupler 58, and a waveguide 55. The incident light of the waveguide dispersion element is coupled into a single waveguide 55 through the input coupler 54, and the other end of this waveguide is connected to the beam splitter 56. The beam splitter 56 distributes its incident light into multiple waveguides connected between the beam splitter 56 and the combiner 57 with equal intensity or unequal intensity and equal phase. For convenience of description, it is described with N waveguides. The lengths of these N waveguides increase 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 dispersion element. Since the lengths of these N waveguides increase, there is a constant phase difference between the output lights of these N waveguides; however, due to the different effective refractive indices of the waveguide for light waves of different wavelengths, the phase differences formed by light waves of different wavelengths after passing through these N waveguides are different. Therefore, the positions of constructive interference of light waves of different wavelengths in the combiner 57 are different. At the position of constructive interference of the light wave with the center wavelength of the signal light in the combiner, a waveguide is used to connect this position to the output coupler 58, and the signal light and the ambient light with a wavelength close to that of the signal light (i.e., the light beam with the same center wavelength as the signal light) can be led out from the combiner 57.

[0070] In some embodiments, the waveguide 55 in the waveguide dispersion element can be an optical fiber. The waveguide can transmit the light beam along a curved path in three-dimensional space. The beam splitter 56, the input coupler 54, the combiner 57, the output coupler 58, and the waveguide 55 can be independent off-chip devices, can also be realized by an on-chip optical path, or can be a combination of on-chip devices and discrete off-chip devices.

[0071] In the above embodiments, the dispersion spectral photosensitive component capable of single-channel measurement is taken as an example for elaboration. However, in some other applications, it is often necessary for the lidar system to synchronously perform multi-channel measurement to obtain a large field of view / higher resolution measurement. In the following embodiments, a planar array dispersion spectral lidar containing a planar array dispersion spectral photosensitive component capable of multi-channel measurement will be provided. The content of the above dispersion spectral photosensitive component is equally applicable to the planar array dispersion spectral photosensitive component described in the following embodiments.

[0072] Figure 6Schematic diagram of the receiving end of a lidar system containing a planar array dispersive spectroscopy photosensitive component according to an embodiment of the present invention. The receiving end includes a planar array dispersive spectroscopy photosensitive component 61 and a receiving optical component 62. Among them, the receiving optical component 62 is composed of at least one lens or lens array, and is used to collect a part of the laser beam (signal light) reflected by an object in the target space and other ambient light beams from the environment, such as reflected beams 631, 632, and 633 from different field-of-view regions (different channels) in the field of view. The reflected beams are collected by the receiving optical component 62 and incident on the planar array dispersive spectroscopy photosensitive component 61. The planar array dispersive spectroscopy photosensitive component 61 includes a planar array diaphragm 615, a collimating device 614, a filter 613, a dispersive device 612, and a planar array detector 611 arranged in sequence along the incident optical path.

[0073] A plurality of holes or slits arranged in a planar array are provided on the planar array diaphragm 615, and each hole or slit is used to receive the beam within the corresponding incident field-of-view angle of the corresponding receiving optical component 62, such as Figure 6Schematically shown are 3 holes or slits respectively for receiving incident light beams 631, 632, and 633 from three different directions. For the convenience of illustration, only three channels are taken as examples here, but it should not be understood as being limited to only three channels. The number and arrangement form of the holes or slits on the area array diaphragm 615 determine the field of view angle and imaging resolution of the entire photosensitive component 61. Each light beam passing through the area array diaphragm 615 further enters the collimating device 614; the collimating device 614 collimates the light beams passing through the diaphragm into multi-channel parallel light beams, and then the parallel light beams enter the filter 613; the filter 613 is a band-pass filter for filtering the incident light beams, and only allows narrow-band wavelength light beams within a certain bandwidth range centered on the central wavelength of the signal light to pass through. The narrow-band wavelength light beams emitted from the filter 613 enter the dispersive device 612, and the dispersive device 612 disperses the incident narrow-band wavelength light beams along 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, multiple light beams a, b, c arranged along the wavelength are formed on the surface of the area array detector 611 (only three light beams are taken as examples for illustration, and actually there can be more light beams). The area array detector 611 includes a plurality of pixels 616 arranged in a two-dimensional area array (such as pixels like APD, SPAD, etc.). Generally, the total number of pixels is greater than the total number of holes or slits on the area array diaphragm. Preferably, corresponding pixel groups are respectively set on the area array detector 611 for each hole or slit, and each pixel group is spatially independent and used to respectively receive the light beams transmitted from their corresponding diaphragm holes or slits. Due to the effect of dispersion, light beams a, b, c of different wavelengths will enter different positions in the pixel group. If the wavelength of the b light beam is the same as the wavelength of the signal light, the signal generated by the pixels for receiving the b light beam will be read out by the subsequent control and processor, and the flight time of the photons can be calculated based on the read optical signal. Further, the distance to the target can be calculated according to 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 achieved, improving the measurement accuracy.

[0074] In some embodiments, the collimating device 614 can be composed of one or more combinations of at least one lens, a microlens array, a mirror (including various types of mirrors such as a plane mirror, a curved mirror, a reflecting prism, etc.), and an area array waveguide transmission element.

[0075] In some embodiments, the dispersive device 612 includes a dispersive element, where the dispersive element can be one or more combinations of a prism, a grating, and a dispersive hologram. The dispersive device 612 can also include a converging lens, which can be composed of one or more combinations of at least one lens, a microlens array, and a mirror.

[0076] In some embodiments, the dispersive device 612 can also be an area array waveguide dispersive element, which consists of multiple such asFigure 5a , Figure 5b It is composed of the waveguide dispersion element arrangement shown. Each waveguide dispersion element in the area array waveguide dispersion element corresponds one-to-one with the holes or slits on the diaphragm, and is respectively used to receive the light beams transmitted from the corresponding holes or slits.

[0077] For the area array dispersive spectral lidar, in order to enable the lidar system to achieve better performance, it is necessary to consider the collimating device and the dispersive device as a whole to design the corresponding receiving end of the area array dispersive spectral lidar. Several receiving end embodiments will be proposed below according to the main idea of the present invention.

[0078] Figure 7 It is a schematic diagram of the receiving end of the area array dispersive spectral lidar according to an embodiment of the present invention. The receiving end includes an area array dispersive spectral photosensitive component 71 and a receiving optical component 72; wherein, the receiving optical component 72 is composed of at least one lens or a lens array, and is used to collect a 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 731, 732 and 733 from different field-of-view regions (different channels) in the field of view. The reflected beams are collected by the receiving optical component 72 and incident on the area array dispersive spectral photosensitive component 71. The dispersive spectral photosensitive component 71 includes an area array diaphragm 715, a first microlens array 714, a filter 713, a dispersive device 712 and an area array detector 711.

[0079] 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 within the corresponding incident field of view angle (channel) of the corresponding receiving optical component 72. Each light beam passing through the area array diaphragm 715 further enters the first microlens array 714; each microlens in the first microlens array 714 corresponds to a hole or slit in the area array diaphragm 715 one by one, and collimates the light beam passing through the diaphragm into a parallel light beam respectively, and the parallel light beam then enters the filter 713; the filter 713 allows the narrowband wavelength light beam within a certain bandwidth range centered on the central wavelength of the signal light to pass through, and the passed narrowband wavelength light beam then enters the dispersion device 712. The dispersion device 712 includes a dispersion element 717 and a second microlens array 716. The dispersion element 717 can be one or a combination of a prism, a grating, and a dispersion hologram, and is used to disperse the incident narrowband wavelength light beam in at least one direction according to the wavelength; each microlens in the second microlens array 716 corresponds to each microlens in the first microlens array 714 or a hole or slit in the area array diaphragm 715 one by one, and is used to converge / focus the light beam from the dispersion element 717 to enter the corresponding pixel on the area array detector 711. Due to the dispersion effect of the dispersion element 717, the light beams from the same diaphragm will enter different pixels according to different wavelengths, so that their spatial separation is achieved. Finally, the pixel signals of the pixels receiving the light beam consistent with the signal light wavelength are subsequently read out by the control and processor.

[0080] Figure 8 FIG. is a schematic diagram of the receiving end of an area array dispersion spectrum lidar according to another embodiment of the present invention. The receiving end includes an area array 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 a lens array, and is used to collect a part of the laser light beam (signal light) reflected by an object in the target space and other ambient light beams from the environment, such as the reflected light beams from different field of view regions (different channels) in the field of view. For the convenience of illustration, only the channel 831 is taken as an example in this embodiment. The reflected light beam is collected by the receiving optical group 82 and enters the area array dispersion spectrum photosensitive component 81. The dispersion spectrum photosensitive component 81 includes an area array diaphragm 815, a first microlens array 814, a filter 813, a dispersion device 812, and an area array detector 811.

[0081] Different from Figure 7 the embodiment shown, Figure 8The dispersion device 812 in the illustrated embodiment includes a second microlens array 819, a first lens 818, a dispersion element 817, and a second lens 816 that are sequentially arranged along the optical path. Among them, each microlens in the second microlens array 819 corresponds one-to-one with each microlens in the first microlens array 814 or the holes or slits in the area array aperture 815, and is used to receive and converge the collimated light beams collimated by the first microlens array 814; the first lens 818 receives the light beams converged by the second microlens array 819, collimates and expands them, and the expanded parallel light beams are then incident on the dispersion element 817. After dispersion, they are incident on the second lens 816. The second lens 816 is used to converge or focus the dispersed light beams to be incident on the corresponding pixels on the area array detector 811. Due to the dispersion effect of the dispersion element 817, light beams of different wavelengths are incident on the second lens 816 in different directions, so that the light beams from the same aperture are incident on different pixels according to different wavelengths, so that their separation in space, and finally the pixel signals of the light beams consistent with the signal light wavelength are read out by the subsequent control and processor. Among them, the first lens 818 and the second lens 816 can be single-piece lenses or lens groups composed of multiple lenses.

[0082] Figure 9 FIG. is a schematic diagram of the receiving end of an area array dispersion spectrum lidar according to another embodiment of the present invention. The receiving end includes an area array 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, and is used to collect a part of the laser beam (signal light) reflected back by an object in the target space and other ambient light beams from the environment, such as reflected light beams 931, 932, and 933 from different field-of-view regions (different channels) in the field of view. The reflected light beams are collected by the receiving optical group 92 and incident on the area array dispersion spectrum photosensitive component 91.

[0083] and Figure 7 、 Figure 8 different from the illustrated embodiment, Figure 9 the dispersion device 912 in the embodiment includes an area array waveguide dispersion element 912 composed of a plurality of waveguide dispersion elements 916. Among them, each waveguide dispersion element 916 is respectively used to receive the light beam from the corresponding aperture hole or slit, and selectively output the light beam consistent with the central wavelength of the signal light to be incident on the corresponding pixel of the area array detector 911. Generally, each waveguide dispersion element 916 on the area array waveguide dispersion element 912 corresponds one-to-one with each microlens on the first microlens array 914 or with each hole or slit on the aperture 915, including one-to-one correspondence in terms of quantity and / or arrangement.

[0084] InFigures 7-9 In the illustrated embodiments, the collimating device is a microlens array. 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.

[0085] Referring to Figure 10 as shown, Figure 10 is a schematic diagram of the receiving end of a planar array dispersive spectral lidar according to another embodiment of the present invention. The receiving end includes a planar array dispersive spectral photosensitive component 101 and a receiving optical component 102. Among them, the dispersive spectral photosensitive component 101 includes a planar array aperture 1015, a first lens 1014, a filter 1013, a dispersive device 1012, and a planar array detector 1011.

[0086] A plurality of holes or slits arranged in a planar array are provided on the planar array aperture 1015, and each hole or slit is used to receive the light beam within the corresponding incident field of view angle of the corresponding receiving optical component 102. Each light beam passing through the planar array aperture 1015 further enters the first lens 1014, and the first lens 1014 collimates the light beam passing through the aperture into a parallel light beam, and the parallel light beam then enters the filter 1013; the filter 1013 allows the narrowband wavelength light beam within a certain bandwidth range centered on the central wavelength of the signal light to pass through, and the passed narrowband wavelength light beam then enters 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 narrowband wavelength light beam along at least one direction according to the wavelength; the second lens 1016 cooperates with the first lens 1014 to converge / focus the incident parallel light beam to the corresponding pixel on the planar array detector 1011. Due to the dispersion effect of the dispersive element 1017, the light beams from the same aperture will be incident on different pixels according to different wavelengths, so that their separation in space is achieved, and finally the pixel signals of the light beams consistent with the signal light wavelength are read out by the subsequent control and processor. Among them, the first lens 1014 and the second lens 1016 can be single-piece lenses or lens groups composed of multiple lenses.

[0087] Referring to Figure 11 as shown, Figure 11 is a schematic diagram of the receiving end of a planar array dispersive spectral lidar according to another embodiment of the present invention. The receiving end includes a planar array dispersive spectral photosensitive component 111 and a receiving optical component 112; among them, the dispersive spectral photosensitive component 111 includes a planar array aperture 1115, a collimating device 1114, a filter 1113, a dispersive device 1112, and a planar array detector 1111.

[0088] 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 of view angle of the corresponding receiving optical component 112. Each light beam passing through the area array diaphragm 1115 further enters the collimating device 1114. The collimating device 1114 includes an area array waveguide transmission element composed of a plurality of waveguide transmission elements 117. Each of the waveguide transmission elements 117 is respectively used to receive the light beam from the corresponding diaphragm hole or slit, and transmit and collimate the light beam and then emit it. Generally, each of the waveguide transmission elements 117 on the area array waveguide transmission element corresponds one-to-one with each of the holes or slits on the diaphragm 1115, and the one-to-one correspondence includes the one-to-one correspondence in terms of quantity and / or arrangement. In one embodiment, the collimating device 1114 further includes lenses arranged at the incident coupler and / or the output coupler ends of each waveguide transmission element, such as the first microlens array 116 and / or the second microlens array 118. Each microlens in the microlens array corresponds one-to-one with each of the waveguide transmission elements.

[0089] The parallel light beam collimated by the collimating device 1114 then enters the filter 1113; the filter 1113 allows the narrowband wavelength light beam within a certain bandwidth range centered on the central wavelength of the signal light to pass through, and the passed narrowband wavelength light beam then enters the dispersion device 1112. The dispersion device 1112 includes a dispersion element 115 and a third microlens array 114. The dispersion element 115 is used to disperse the incident narrowband wavelength light beam along at least one direction according to the wavelength; each microlens in the third microlens array 114 corresponds one-to-one with each of the waveguide transmission elements 117 in the area array waveguide transmission element and / or each of the holes or slits on the diaphragm 1115, and is used to converge / focus the light beam from the dispersion element 115 to enter the corresponding pixel on the area array detector 1111.

[0090] In Figure 9 the said embodiment, a planar array waveguide dispersion element is adopted in the dispersion element of the dispersion spectrum photosensitive component. In Figure 11 the said embodiment, the collimating device adopts a planar array waveguide transmission element. Since the waveguide can transmit the light beam along a curved path in three-dimensional space, the multiple output couplers in the planar array waveguide dispersion (transmission) element can be rearranged or the direction can be adjusted in space, and can be rearranged relative to the spatial arrangement of the multiple input couplers to achieve the arrangement and / or direction of the output light beam required by the system. For example, due to the arrangement requirements of the pixels on the area array detector, in order to more evenly introduce the light beam in each diaphragm aperture into the corresponding pixel, the arrangement and / or direction of the output couplers can be readjusted to achieve a flexible configuration of the mapping relationship between the diaphragm aperture and the detector pixel.

[0091] It can be understood that any device with the same function as the collimating device can be used to replace the collimating device in the dispersive spectral photosensitive component. Similarly, any device with the same function as the dispersive element can be used to replace the dispersive element. Moreover, the combination method of the collimating device and the dispersive element is not limited to the several types in the above embodiments. Any combination based on the idea of the present invention and capable of achieving similar functions belongs to the protection scope of the present invention.

[0092] The transmitting end of the dispersive spectral lidar will be described later. Referring to Figure 1 , the transmitting end 12 includes a light source 13 and a transmitting optical component 14, and is used to emit laser beams (signal light beams) of at least one channel into space. For different application requirements, the transmitting end can be configured in different forms.

[0093] In some embodiments, the transmitting end is used to emit a speckle beam, and the emitted speckle beam can be a single-point light spot or a multi-point light spot. In order to obtain high-spatial-resolution point cloud data within the measurement field of view, a scanning element can also be added to the transmitting optical component 14 in one embodiment. In addition, the transmitting optical component 14 also includes beam shaping elements, such as lenses, mirrors, etc., which are used to shape the divergent beam emitted by the light source into a single-point or multi-point light spot and irradiate it onto the target. It can be understood that when the transmitting end only emits a single-point light spot, only one light passing hole is required for the diaphragm in the corresponding receiving end, and the light passing hole is located on the optical axis of the receiving system; when the reflecting end emits multiple point light spots, the diaphragm has multiple light passing holes, and each light passing hole forms a one-to-one correspondence with each emitted point light spot. For multi-point light spots, they can be arranged in a line or two-dimensionally in the x direction and the y direction.

[0094] In some embodiments, the transmitting end is used to emit a single-line light spot or a multi-line light spot. Similarly, in order to obtain high-spatial-resolution point cloud data within the measurement field of view, a scanning element can also be added to the transmitting optical component 14 in one embodiment. In addition, the transmitting optical component 14 also includes beam shaping elements, such as lenses, mirrors, etc., which are used to shape the divergent beam emitted by the light source into a single-line or multi-line light spot and irradiate it onto the target. Generally, the light spot of the line has a relatively small beam divergence angle in one direction, such as 0.05° to 0.15°, while the divergence angle in the other direction reaches several tens of degrees. When the emitted light spot is a multi-line light spot, the lines are parallel to each other.

[0095] In the point light spot and line light spot embodiments, the light source at the transmitting end can be a single-point edge-emitting laser, a single-point vertical-cavity surface-emitting laser (VCSEL), a laser array composed of multiple edge-emitting lasers, a VCSEL array, and a VCSEL with controllable partitions, etc. The beam shaping device is composed of a combination of one or more of a lens, a microlens array, a Metasurface device, a beam splitting prism, and a mirror. The scanning element can be composed of an MEMS mirror, a rotating prism, a pair of rotating prisms, a mechanical galvanometer, an OPA scanning device, etc.

[0096] In some embodiments, the transmitting end can directly emit multiple point light spots without passing through a scanning element. The transmitting end includes a surface array light source composed of multiple sub-light sources and a transmitting optical component. The divergent light beams emitted by the sub-light sources are shaped into point light spots or line light spots by the beam shaping element in the transmitting optical component and then emitted into space. The processing and controller can selectively light up the corresponding pixels on the receiving end detector only when the corresponding sub-sources in the surface array light source are lit by partitioning the multiple sub-sources in the surface array light source, so as to achieve scanning measurement in 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, a VCSEL surface array laser that can be partitioned and lit, etc.

[0097] It can be understood that when the structure or components of the position or hardware in the system of the present invention are correspondingly changed or simply replaced to meet the requirements, its essence still adopts the dispersive spectral lidar of the present invention, so it should be regarded as within the protection scope of the present invention.

[0098] It can be understood that the above content is a further detailed description of the present invention in combination with specific / preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several alternatives or modifications can be made to these described embodiments, and these alternative or modified forms should all be regarded as belonging to the protection scope of the present invention. In the description of this specification, the descriptions with reference to terms such as "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention.

[0099] In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. Additionally, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of different embodiments or examples. Although the embodiments of the present invention and their 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.

[0100] Furthermore, the scope of the present invention is not intended to be limited to the specific embodiments of the processes, machines, manufactures, compositions of matter, means, methods, and steps described in the specification. Those of ordinary skill in the art will readily understand that the presently existing or later to be developed above-disclosed, processes, machines, manufactures, compositions of matter, means, methods, or steps that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein can be utilized. Accordingly, the appended claims are intended to include such processes, machines, manufactures, compositions of matter, means, methods, or steps within their scope.

Claims

1. A dispersion spectroscopic lidar system, characterized in that, Comprising: A transmitting end configured to transmit a signal light beam; A receiving end including a receiving optical component and a dispersion spectrum photosensitive component; wherein, the receiving optical component is configured to receive at least a part of the signal light beam reflected back by the target and a part of the ambient light beam and incident on the dispersion spectrum photosensitive component; the dispersion spectrum photosensitive component includes a dispersion device and a photosensitive detector; wherein, the dispersion 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 pixel group in the photosensitive detector, so that the incident light beam is spatially distinguished according to the wavelength; the field of view angle of the receiving end is greater than the divergence angle of the signal light beam; The control and processor is configured to only read out the incident light beam signal consistent with the wavelength of the signal light beam and calculate the flight time of photons based on the incident light beam signal.

2. The dispersion spectral lidar system according to claim 1, wherein: The transmitting end includes a light source and a transmitting optical component, and the light source is configured to emit a signal light beam and transmit it to the target after being modulated by the transmitting optical component.

3. The dispersion spectral lidar system according to claim 1, wherein: The signal light beam includes one of a speckle beam, a line beam, and a floodlight beam.

4. The dispersion spectral 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 channels and the receiving channels correspond to each other one by one.

5. The dispersion spectral lidar system according to claim 1, characterized in that: The transmitting end and the receiving end are arranged in a coaxial form.

6. The dispersion spectral lidar system according to claim 1, wherein: The transmitting end and the receiving end are arranged in an off-axis form.

7. The dispersion spectral lidar system according to claim 1, characterized in that: The transmitting end and the receiving end are mounted on the same substrate.

8. The dispersion spectral lidar system according to claim 1, wherein: 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.

9. A method for measurement using a dispersion spectral lidar system, characterized in that: Using the dispersion spectrum lidar system according to any one of claims 1-8, comprising the following steps: Transmitting a signal light beam; Receiving at least a part of the signal light beam reflected back by the target and a part of the ambient light beam; Dispersing the received incident light beam to spatially distinguish light beams of different wavelengths; Selecting the incident light beam signal consistent with the wavelength of the signal light beam and calculating the flight time of photons based on the incident light beam signal.

Images