CN113748358A

CN113748358A - Laser receiving device, laser receiving method and laser radar

Info

Publication number: CN113748358A
Application number: CN202080031652.5A
Authority: CN
Inventors: 马丁昽; 刘迎春
Original assignee: Suteng Innovation Technology Co Ltd
Current assignee: Suteng Innovation Technology Co Ltd
Priority date: 2020-03-10
Filing date: 2020-03-10
Publication date: 2021-12-03
Anticipated expiration: 2040-03-10
Also published as: WO2021179158A1

Abstract

A laser receiving device, a laser receiving method and a laser radar belong to the field of photoelectric detection. The receiving apparatus includes: the device comprises a receiving objective lens (10), a spatial filter (11), an optical waveguide light equalizer (13), a spectral filter (12) and a photoelectric detector (14), wherein the spatial filter (11) performs spatial filtering on an echo light signal from the receiving objective lens (10), the echo light signal in a preset field of view is reserved, and the signal-to-noise ratio of the laser receiving device can be increased; the optical waveguide light equalizer (13) performs light equalizing processing on the echo light signals after the spatial filtering processing to realize that the echo light signals are uniformly irradiated on the photoelectric detector (14), and the energy of light spots is uniformly distributed on each pixel of the photoelectric detector (14), so that the photoelectric detector (14) has lower false alarm rate; the spectral filter (12) performs band-pass filtering on the echo optical signals, reserves the echo optical signals in a preset frequency band, can further improve the signal-to-noise ratio of the laser receiving device, improves the accuracy of the photoelectric detector (14), and reduces the interference of the noise optical signals on the photoelectric detector (14).

Description

Laser receiving device, laser receiving method and laser radar

Technical Field

The invention relates to the field of photoelectric detection, in particular to a laser receiving device, a laser receiving method and a laser radar.

Background

The laser radar is a radar system which emits a laser echo optical signal to detect characteristic quantities such as a position, a speed and the like of a target, and the working principle of the radar system is that the detection laser echo optical signal is firstly emitted to the target in a field of view, then the received reflected echo optical signal reflected from the target is received, a photoelectric detector carries out photoelectric conversion on the reflected laser echo optical signal to obtain an electric signal, and the electric signal is appropriately processed to obtain related information of the target, for example: target distance, reflectivity, orientation, velocity, attitude, and even shape. Because the reflected laser echo optical signal is generally weak, the background light noise outside the field of view has a large interference on the reflected laser echo optical signal, thereby affecting the detection performance of the photoelectric detector, and how to reduce the interference of the background light noise on the reflected laser is a problem to be solved urgently at present.

Disclosure of Invention

The embodiment of the invention provides a laser receiving device, a laser receiving method and a laser radar, and solves the problem that background light noise has large interference on echo light signals in the related art.

In order to solve the technical problem, the embodiment of the invention discloses the following technical scheme:

in a first aspect, the present application provides a laser receiving apparatus, including: the system comprises a receiving objective lens, a spatial filter, a spectral filter and a photoelectric detector;

the receiving objective lens is used for receiving echo optical signals and transmitting the echo optical signals to the spatial filter;

the spatial filter is used for spatially filtering the echo optical signal from the receiving objective lens to filter noise optical signals outside a preset field of view, and transmitting the spatially filtered echo optical signal to the spectral filter;

the spectral filter is used for performing band-pass filtering on the echo optical signal from the spatial filter to filter noise optical signals outside a preset frequency band, and transmitting the echo optical signal subjected to band-pass filtering to the photoelectric detector;

and the photoelectric detector is used for performing photoelectric conversion on the echo optical signal from the spectral filter to obtain an electric signal.

In one possible design, further comprising:

the optical waveguide light equalizer is used for performing band-pass filtering on the echo optical signals from the spatial filter to filter noise optical signals outside a preset frequency band, and transmitting the echo optical signals subjected to band-pass filtering to the photoelectric detector.

In one possible design, the spatial filter comprises a diaphragm, which is an aperture diaphragm, a field diaphragm, a vignetting diaphragm, or a stray light eliminating diaphragm.

In one possible embodiment, the aperture size of the diaphragm is θ × f, θ denotes the divergence angle of the emitted optical signal, and f is the focal length of the receiving objective.

In one possible design, the receiving objective adopts a telecentric light path, and the optical waveguide light equalizer is arranged in parallel with the optical axis of the receiving objective; or when the receiving objective adopts a non-telecentric optical path, the optical waveguide light homogenizer and the optical axis of the receiving objective are arranged at a preset angle.

In one possible design, the number of the optical waveguide dodging devices is multiple, the multiple optical waveguide dodging devices are arranged in N rows and M columns, and M and N are integers greater than or equal to 1; the number of the photoelectric detectors is equal to M multiplied by N, the number of the photoelectric detectors is equal to the number of the optical waveguide dodging devices, and the number of the photoelectric detectors is equal to the number of the optical waveguide dodging devices.

In one possible design, the optical waveguide homogenizer is in the shape of a cylinder, a truncated cone, a cuboid or a truncated pyramid.

In one possible design, the photodetector is an APD detector or a SiPM detector.

In one possible design, further comprising: a collimating lens, an angle filter and a focusing lens;

the collimating lens is used for collimating the echo optical signal from the spatial filter and transmitting the converted echo optical signal to the angle filter;

the angle filter is used for carrying out angle filtering on the echo optical signals from the collimating lens and transmitting the echo optical signals after the angle filtering to the focusing lens;

the focusing lens is used for focusing the echo optical signal from the angle filter and transmitting the focused echo optical signal to the optical waveguide dodging device.

In one possible design, the angular filter is a dow mirror.

In a second aspect, the present application provides a laser receiving method, including:

the receiving objective lens receives an echo optical signal and transmits the echo optical signal to the spatial filter;

the spatial filter performs spatial filtering on the echo optical signal from the receiving objective lens to filter noise optical signals outside a preset field of view, and transmits the echo optical signal after the spatial filtering to the spectral filter;

the spectral filter is used for performing band-pass filtering on the echo optical signal from the spectral filter to filter noise optical signals outside a preset frequency band, and transmitting the echo optical signal subjected to band-pass filtering to the photoelectric detector;

and the photoelectric detector performs photoelectric conversion on the echo optical signal from the spectral filter to obtain an electric signal.

In one design, the optical waveguide dodging device performs dodging on the echo optical signal from the spatial filter, and transmits the dodged echo optical signal to the spectral filter.

In a third aspect, an embodiment of the present application provides a laser radar, including the above laser receiving apparatus.

In this embodiment, the spatial filter performs spatial filtering on the echo optical signal from the receiving objective lens to filter noise optical signals outside the preset field of view, and retains the echo optical signal in the preset field of view, so that the signal-to-noise ratio of the laser receiving device can be increased, and the optical noise signal is prevented from causing large interference to the echo optical signal; spectral filter carries out band-pass filtering to echo light signal to the noise light signal outside the frequency channel is predetermine in the filtering, remains the echo light signal of predetermineeing the frequency channel, can further increase laser receiving device's SNR, improves photoelectric detector's the degree of accuracy, reduces the interference of noise light signal to photoelectric detector.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a block diagram showing a structure of a laser receiving apparatus according to an embodiment of the present invention;

fig. 2 is a schematic optical path diagram of a laser receiving apparatus according to an embodiment of the present invention;

fig. 3 is a block diagram showing a structure of a laser receiving apparatus according to an embodiment of the present invention;

fig. 4 is a schematic optical path diagram of a laser receiver according to an embodiment of the invention;

fig. 5 is a schematic flow chart of a laser receiving method according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described below with reference to the drawings in the embodiments of the present invention.

Referring to fig. 1 and 2, fig. 1 is a schematic structural diagram of a laser receiving apparatus according to an embodiment of the present invention, and as shown in fig. 1, the laser receiving apparatus includes: a receiving objective lens 10, a spatial filter 11, a spectral filter 12 and a photodetector 14.

The receiving objective 10 may be composed of one or more lenses, and the receiving objective may adopt a telecentric optical path or a non-telecentric optical path. The receiving objective lens can be provided with a plurality of receiving light channels, and the echo light signals from the object enter the receiving light channels to obtain emergent light signals; the receiving objective may be composed of multiple sets of lenses. In the telecentric optical path, an emergent light signal of the receiving objective lens 10 is parallel to an optical axis of the receiving objective lens 10; in the non-telecentric optical path, a preset angle is formed between an emergent light signal of the receiving objective lens 10 and an optical axis; correspondingly, the included angle between the optical device (such as a diaphragm or an optical waveguide light equalizer) arranged behind the receiving objective lens 10 and the optical axis is also equal to the preset angle, so that the emergent light signal of the receiving objective lens 10 is perpendicular to the input port of the optical device; wherein the preset angle is related to an included angle between the emitted light signal corresponding to the echo light signal and the optical axis, for example: an included angle between the emission optical signal and the optical axis of the receiving objective lens 10 is 45 degrees, so that the emission optical signal forms an echo optical signal after encountering an object, and an included angle between an emission optical signal obtained after the echo optical signal enters the receiving objective lens 10 and the optical axis is also 45 degrees.

For example: referring to fig. 2, the receiving objective lens 10 is provided with a plurality of light receiving channels, each of which includes a spatial filter 11, a spectral filter 12, an optical waveguide homogenizer 13, and a photodetector 14.

The spatial filter 11 is configured to filter noise optical signals outside an effective field of view, where the noise optical signals may be sunlight background noise optical signals and invalid echo optical signals scattered back by the atmosphere, the effective field of view includes a vertical field of view and a horizontal field of view, one spatial filter 11 is disposed in each receiving optical channel, and a total of the horizontal fields of view of the spatial filters 11 and a total of the vertical fields of view of the spatial filters 11 constitute a total effective field of view of the laser receiving apparatus. For example: the laser receiving device is provided with 100 receiving optical channels, correspondingly, the 100 receiving optical channels comprise 100 spatial filters 11 in total, the vertical field of view of each spatial filter 11 is 1 degree, the horizontal field of view is 2 degrees, and each spatial filter 11 filters noise optical signals with the vertical field of view being beyond 1 degree and the horizontal field of view being beyond 2 degrees. Then for the laser receiving device, the laser receiving device may filter out noise optical signals beyond a vertical field of view of 1 degree × 100 ═ 100 degrees and beyond a horizontal field of view of 2 degrees × 100 ═ 200 degrees.

Further, the spatial filter 11 includes a diaphragm, which is an aperture for limiting the light beam in the optical system, and the size of the aperture may be fixed or adjustable. The diaphragm may be an aperture diaphragm, a field diaphragm, a vignetting diaphragm or a stray light eliminating diaphragm, depending on the type. Wherein the aperture stop can limit the beam solid angle (cone angle). The field stop may limit the maximum extent to which an object plane or object space can be imaged by the optical system. The vignetting diaphragm passes a portion of the beam emitted from a point off the object space axis with the purpose of reducing off-axis aberrations. The stray light eliminating diaphragm is used for limiting optical signals emitted from a non-imaging object, optical signals reflected by each refraction surface of an optical system, optical signals reflected by the inner wall of an instrument and the like.

Further, the stop may be arranged in the focal plane of the receiving objective 10, i.e. the distance between the stop and the receiving objective 10 is equal to the focal length of the receiving objective 10. When the number of the diaphragms is multiple, the diaphragms are all arranged in the focal plane, and the intervals between any two adjacent diaphragms are equal. Wherein the aperture size of the diaphragm is θ xf, θ represents the divergence angle of the emitted optical signal, and the divergence angle represents the speed at which the optical beam diverges outward from the beam waist; f represents the focal length of the receiving objective lens 10, the diaphragm corresponds to one receiving optical channel, the emitted optical signal meets the object to form an echo optical signal, and the echo optical signal is incident into the receiving optical channel.

The spectral filter 12 is a band-pass filter for filtering out optical noise outside a preset frequency band, and the spectral filter may be a narrow-band filter. The main parameters of the narrow-band filter comprise center wavelength, bandwidth, peak transmittance, cut-off range and cut-off depth; wherein the center wavelength represents an operating wavelength of the optical system; the bandwidth represents the distance between two positions in the passband where the transmittance is the peak transmittance, also referred to as the half-width height; the peak transmittance represents the highest transmittance in the pass band; the cutoff range means a wavelength range requiring cutoff other than the pass band; for the narrow-band filter, one section is front cut-off, namely one section with cut-off wavelength smaller than the central wavelength, and the other section is long cut-off, namely one end with cut-off wavelength higher than the central wavelength; the cut-off depth represents the maximum amount of transmittance of light that can be transmitted in the cut-off band.

The optical waveguide dodging device 13 is used for dodging the echo optical signal, the optical waveguide dodging device 13 may include a light guide component and a dodging component, and the light guide component and the dodging component may be integrally formed; the light guide component is used for transmitting echo light signals, the dodging component is used for converting the echo light signals with energy distributed in a concentrated mode into echo light signals with energy distributed uniformly, and the dodging component can be a dodging lens system consisting of a plurality of lenses; for example: and the output of uniform echo optical signals is realized by utilizing the double fly-eye lens arrays on the front and the back surfaces. The light guide component can be in the shape of a cylinder, a cuboid, a circular table, a prismatic table and the like, and the shape of the facula subjected to the dodging treatment can be circular or rectangular; the light guide member may be a solid waveguide or a hollow waveguide. The main parameters of the optical waveguide homogenizer 13 include: the optical signal detector 14 comprises a plurality of pixels (pixels), each pixel is composed of a plurality of cells (cells), each cell corresponds to an avalanche diode used for detecting a single photon, and the light spot covers one or more pixels on the photoelectric detector 14. For example: the size of the light spot output by the optical waveguide dodging device 13 is represented by the diameter or the side length; the operating wavelength represents the wavelength of the echo optical signal that the optical waveguide homogenizer 13 can perform the homogenization treatment; the size of the incident light spot represents the size of a light spot formed on the optical waveguide homogenizer 13 by the input echo optical signal, and can be represented by using a diameter or a side length; the transmittance is a ratio of the intensity of the output echo optical signal to the intensity of the input echo optical signal, and is generally less than 1.

Further, the light guide member in the optical waveguide homogenizer 13 includes an input port and an output port, the input port representing a cross section of the light signal incident on the light guide member, and the output port representing a cross section of the light signal output from the light guide member. The input port and the output port may be the same or different in shape and size. For example: the input port and the output port of the optical waveguide dodging device 12 are circular, and the areas of the two circles are the same; or the input port and the output port of the optical waveguide dodging device 12 are circular, and the area of the input port is smaller than that of the output port, so as to increase the area of the light spot; or the input port and the output port are rectangular, and the areas of the two rectangles are equal; or the input port and the output port are rectangular in shape, and the area of the input port is smaller than that of the output port. The shape and size of the output port determines the shape and size of the spot of light impinging on the photodetector 14.

In a possible embodiment, one optical waveguide homogenizer 13 is located in one light receiving channel, and when the number of the optical waveguide homogenizers 13 is multiple, the optical waveguide homogenizers 13 can be arranged in a one-dimensional manner or a two-dimensional manner, i.e. multiple optical waveguide homogenizers 13 are arranged in a row, or multiple optical waveguide homogenizers 13 are arranged in a column. The optical waveguide homogenizers 13 are arranged in a two-dimensional manner, namely, a plurality of optical waveguide homogenizers 13 are arranged in M rows and N columns, wherein M and N are integers larger than 1. For example: m4, N4, and a plurality of optical waveguide homogenizers 13 arranged in 4 rows and 4 columns.

The principle of the photodetector 14 is a photoelectric effect, which converts an echo optical signal into an electrical signal, the photodetector may be an Avalanche Photo Diode (APD), a PN junction of the APD is made of silicon or germanium, a reverse bias voltage is applied to the PN junction, the incident echo optical signal is absorbed by the PN junction to form a photocurrent, and the photocurrent is multiplied after the reverse bias voltage is increased. The photodetector 14 may also be a single photon photodetector, for example: SiPM (silicon photomultiplier) or SPAD (Single photon avalanche Diode), a Single photon photodetector has extremely high sensitivity, can detect the minimum energy quantum-photon of light, and can detect and count Single photon. The number of the photodetectors 14 may be one or more, and when the number of the photodetectors 14 is multiple, the number of the spatial filter 11, the spectral filter 12, the optical waveguide dodging device 13 and the number of the photodetectors 14 are equal, and the two are arranged in a one-to-one manner. The photodetector 14 comprises a plurality of pixels (pixels), each pixel comprising a plurality of cells (cells), and the light spot output by the optical waveguide dodging device 13 covers one or more pixels on the photodetector 14. The size and shape of the spot output by the optical waveguide homogenizer 13 is related to the size and shape of the output port of the optical waveguide homogenizer 13. The size and the number of the pixels included in the photodetector 14 can be determined according to actual requirements, and the embodiment of the present application can increase the dynamic range of the photodetector 14 by increasing the number of the pixels, and reduce the dynamic range of the photodetector 14 by reducing the number of the pixels, so that the photodetector 14 can detect an optical signal in a larger detection range, thereby increasing the detection probability of the photodetector 14. In addition, when the area of the input port of the optical waveguide device 13 is larger than the area of the output port, that is, the output optical signal has a larger light spot than the input optical signal, the output light spot can cover more pixels on the photodetector 14, and thus the detection probability of the photodetector can be further improved.

Referring to fig. 1 and 2, the spectral filter 12 is located in front of the optical waveguide homogenizer 13, and the echo optical signal is transmitted to the photodetector 14 through the receiving objective lens 10, the spatial filter 11, the spectral filter 12, and the optical waveguide homogenizer 13 in sequence.

The working principle of the laser receiver of fig. 1 and 2 is explained in detail below:

and the receiving objective lens 10 is used for receiving the echo optical signals and transmitting the echo optical signals to the spatial filter.

The spatial filter 11 is configured to spatially filter the echo optical signal from the receiving objective 10 to filter out noise optical signals outside a preset field of view, and transmit the spatially filtered echo optical signal to the spectral filter 12. The spatial filter 11 filters noise optical signals outside the preset view field, retains echo optical signals within the preset view field, reduces the interference of the noise optical signals with normal echo optical signals, and improves the signal-to-noise ratio of the laser receiving device.

The spectral filter 12 is configured to band-pass filter the echo optical signal from the spatial filter 11 to filter out noise optical signals outside a preset frequency band, and transmit the band-pass filtered echo optical signal to the photodetector 14. The spectral filter 12 filters noise optical signals outside the working frequency band, retains echo optical signals within the working frequency band, and reduces interference of the noise optical signals on normal echo optical signals.

And a photodetector 14 for photoelectrically converting the echo optical signal from the spectral filter 12 to obtain an electrical signal.

In one possible embodiment, the laser receiving apparatus further includes: and the optical waveguide dodging device 13 is used for carrying out dodging processing on the echo optical signals from the spectral filter 12 and transmitting the echo optical signals after the dodging processing to the photoelectric detector 14. The optical waveguide light equalizer 13 can irradiate light spots with uniformly distributed energy onto the photodetector after performing light equalizing processing on the echo light signal, so that each cell on the photodetector detects the same illumination intensity, and false alarm triggered by the fact that the illumination intensity of a certain cell exceeds an alarm threshold is avoided, thereby reducing the false alarm rate of the photodetector.

In another possible embodiment, the spectral filter 12 may also be located behind the optical waveguide homogenizer 12, and the echo optical signal is transmitted to the photodetector through the receiving objective 10, the spatial filter 11, the optical waveguide homogenizer 13, and the spectral filter 12 in sequence. The working principle of the laser receiving device is as follows: and a receiving objective lens 10 for receiving the echo optical signal and transmitting the echo optical signal to a spatial filter 11. And a spatial filter 11 for spatially filtering the echo optical signal from the receiving objective lens 10 and transmitting the spatially filtered echo optical signal to the optical waveguide homogenizer 13. The optical waveguide homogenizer 13 performs a homogenizing process on the echo optical signal from the spatial filter, and transmits the echo optical signal after the homogenizing process to the spectral filter 12. And the spectral filter is used for performing band-pass filtering on the echo optical signal from the optical waveguide dodging device 13 to filter noise optical signals outside a preset frequency band, and transmitting the band-pass filtered echo optical signal to the photoelectric detector 14. The photodetector 14 receives the echo optical signal from the spectral filter 12, and converts the echo optical signal into an electrical signal.

In the embodiment of the invention, the spatial filter performs spatial filtering on the echo optical signal from the receiving objective lens to filter noise optical signals outside a preset field of view, the echo optical signal in the preset field of view is reserved, the signal-to-noise ratio of the laser receiving device can be increased, the angle filter 16 filters the noise optical signal outside the preset angle, the echo optical signal within the preset angle is reserved, the interference of the noise optical signal on a normal echo optical signal is reduced, and the signal-to-noise ratio of the laser receiving device is further improved; the spectral filter carries out band-pass filtering to the echo light signal to the noise light signal outside the preset frequency channel of filtering remains the echo light signal of presetting the frequency channel, improves the degree of accuracy that photoelectric detector detected the light signal, reduces the interference of noise light signal to photoelectric detector.

Referring to fig. 3 and fig. 4, another schematic structural diagram of a laser receiving apparatus provided in an embodiment of the present application is shown, in which the laser receiving apparatus includes: a receiving lens 10, a spatial filter 11, a collimating lens 15, an angle filter 16, a focusing lens 17, a spectral filter 12, an optical waveguide dodging device 13 and a photodetector 14.

The difference between this embodiment and the embodiment in fig. 1 is that this embodiment includes, in addition to: besides the receiving lens 10, the spatial filter 11, the spectral filter 12, the optical waveguide dodging device 13 and the photodetector 14, the receiving lens further includes a collimating lens 15, an angle filter 16 and a focusing lens 17.

In this embodiment, the description of the receiving lens 10, the spatial filter 11, the spectral filter 12, the optical waveguide dodging device 13, and the photodetector 14 may refer to the description of the embodiments in fig. 1 and fig. 2, and will not be repeated herein.

Wherein, the collimating lens 15 is used to convert the incident echo optical signal into an echo optical signal parallel to the optical axis, and the collimating lens 15 may be composed of a single lens, for example: plano-convex or biconvex lenses; it may also consist of a plurality of lenses, for example: a double cemented lens.

The angle filter 16 is configured to filter echo optical signals other than the preset incident angle, where the size of the preset incident angle may be determined according to actual requirements, and the embodiment of the present application is not limited. The angle filter 16 may be a dow reflector, two films are respectively disposed on the upper and lower non-working surfaces of the dow reflector, a dielectric film is disposed on the inner surface, the dielectric film totally reflects the echo optical signal satisfying the incident angle condition, and transmits the echo optical signal not satisfying the incident angle condition; the absorbing film is arranged on the outer surface of the DouWei reflector and used for absorbing the echo optical signals projected by the dielectric film and preventing the echo optical signals transmitted by the dielectric film from generating crosstalk again.

The focusing LENS 17 is also called a gradient-index LENS (G-LENS), and the refractive index of the focusing LENS 17 is gradually decreased along the radial direction, so that the incident echo optical signal parallel to the optical axis is smoothly and continuously converged to one point. The focusing lens 17 may be a spherical lens or a planar lens according to the shape classification. The type of the focusing lens 17 may be a plano-convex lens, a positive meniscus lens, an aspherical lens, a diffractive lens, or a reflective lens.

The working principle of the laser receiving device according to the embodiment of the present application is described below with reference to fig. 3:

and a receiving lens 10 for receiving the echo optical signal and transmitting the echo optical signal to the spatial filter 11.

And a spatial filter 11 for spatially filtering the echo optical signal from the receiving lens 10 to filter out noise optical signals outside a preset field of view, and transmitting the spatially filtered echo optical signal to the collimating lens 15. The spatial filter 11 filters noise optical signals outside the preset view field, retains echo optical signals within the preset view field, reduces the interference of the noise optical signals with normal echo optical signals, and improves the signal-to-noise ratio of echo optical signal transmission.

And a collimating lens 15 for collimating the echo optical signal from the spatial filter 11 and transmitting the collimated echo optical signal to the angle filter 16.

The angle filter 16 is configured to perform angle filtering on the echo optical signal from the collimating lens 16 to filter noise optical signals outside a preset angle, and transmit the echo optical signal after the angle filtering to the focusing lens 17. The angle filter 16 filters noise optical signals outside the preset angle, retains echo optical signals within the preset angle, reduces interference of the noise optical signals on normal echo optical signals, and improves the signal-to-noise ratio of the laser receiving device.

And a focusing lens 17 for performing focusing processing on the echo optical signal from the angle filter 16 and transmitting the focused echo optical signal to the spectral filter 12.

The spectral filter 12 is configured to band-pass filter the echo optical signal from the focusing lens 17 to filter out noise optical signals outside a preset frequency band, and transmit the band-pass filtered echo optical signal to the photodetector 14. The spectral filter 12 filters noise optical signals outside the working frequency band, retains echo optical signals within the working frequency band, and reduces interference of the noise optical signals on normal echo optical signals.

In one possible embodiment, referring to fig. 3, the laser receiving apparatus further includes: and the optical waveguide dodging device 13 is used for carrying out dodging processing on the echo optical signals from the spectral filter 12 and transmitting the echo optical signals after the dodging processing to the photoelectric detector 14. The optical waveguide dodging device 13 can uniformly irradiate the echo optical signal onto the photodetector after dodging the echo optical signal, so that the false alarm rate of the photodetector is improved and reduced.

In another possible embodiment, as shown in fig. 4, the spectral filter 12 may also be located behind the optical waveguide integrator 12, and the echo optical signal is transmitted to the photodetector through the receiving objective 10, the spatial filter 11, the optical waveguide integrator 13, and the spectral filter 12 in sequence. The working principle of the laser receiving device is as follows: and a receiving lens 10 for receiving the echo optical signal and transmitting the echo optical signal to the spatial filter 11. The spatial filter 11 spatially filters the echo optical signal from the receiving lens 10 to filter out a noise optical signal outside a preset field of view, and transmits the spatially filtered echo optical signal to the collimator lens 15. The collimator lens 15 collimates the echo optical signal from the spatial filter 11, and transmits the collimated echo optical signal to the angle filter 16. And an angle filter 16 for angle-filtering the echo optical signal from the collimator lens 15 and transmitting the angle-filtered echo optical signal to the focusing lens 17. And the focusing lens 17 is used for carrying out focusing processing on the echo optical signals from the angle filter 16 and transmitting the echo optical signals after the focusing processing to the optical waveguide dodging device 13. The optical waveguide homogenizer 13 performs a homogenizing process on the echo optical signal from the focusing lens 17, and transmits the echo optical signal after the homogenizing process to the spectral filter 12. The spectral filter 12 is configured to perform band-pass filtering on the echo optical signal of the optical waveguide dodging device 13 to filter noise optical signals outside a preset frequency band, and transmit the echo optical signal after the band-pass filtering processing to the photodetector 14. And a photodetector 14 for photoelectrically converting the echo optical signal from the spectral filter 12 to obtain an electrical signal.

In the embodiment of the invention, the spatial filter performs spatial filtering on the echo optical signal from the receiving objective lens to filter noise optical signals outside a preset field of view, the echo optical signal in the preset field of view is reserved, the signal-to-noise ratio of the laser receiving device can be improved, the optical waveguide dodging device performs dodging processing on the echo optical signal after the spatial filtering processing, the echo optical signal is uniformly irradiated on the photoelectric detector, the energy of light spots is uniformly distributed on each pixel of the photoelectric detector, and the photoelectric detector has lower false alarm rate; spectral filter carries out band-pass filtering to the echo light signal of dodging processing to the noise light signal outside the frequency channel is predetermine in the filtering, remains the echo light signal of predetermineeing the frequency channel, can further increase echo light signal's SNR, improves photoelectric detector's the degree of accuracy, reduces noise light signal to photoelectric detector's interference.

Referring to fig. 5, a schematic flow chart of a laser receiving method according to an embodiment of the present application is shown, where the laser receiving method includes:

and S501, receiving the echo optical signal by the objective lens, and transmitting the echo optical signal to the spatial filter.

S502, the spatial filter performs spatial filtering on the echo optical signal from the receiving objective lens to filter noise optical signals outside a preset field of view, and transmits the echo optical signal after the spatial filtering to the spectral filter.

S503, the spectral filter performs band-pass filtering on the echo optical signal from the spatial filter to filter noise optical signals outside a preset frequency band, and the echo optical signal after the band-pass filtering is transmitted to the photoelectric detector.

And S504, the photoelectric detector performs photoelectric conversion on the echo optical signal from the spectral filter to obtain an electric signal.

In one possible embodiment, the laser receiving method further includes:

the optical waveguide dodging device conducts dodging processing on the echo optical signals from the spatial filter, and the echo optical signals after dodging processing are transmitted to the spectral filter.

In a possible embodiment, the spatial filter comprises a diaphragm, which is an aperture diaphragm, a field diaphragm, a vignetting diaphragm, or a stray light eliminating diaphragm.

In a possible embodiment, the diaphragm is arranged in the focal plane of the receiving objective.

In one possible embodiment, the aperture size of the diaphragm is θ × f, θ represents the divergence angle of the emitted optical signal, and f represents the focal length of the receiving objective.

In a possible implementation mode, the receiving objective adopts a telecentric light path, and the optical waveguide light evener is arranged in parallel to the optical axis of the receiving objective; or the receiving objective adopts a non-telecentric light path, and the optical waveguide light equalizer and the optical axis of the receiving objective are arranged at a preset angle.

In one possible embodiment, the number of the optical waveguide dodging devices is multiple, the multiple optical waveguide dodging devices are arranged in M rows and N columns, and M and N are integers greater than or equal to 1; the number of the photoelectric detectors is multiple, and the number of the photoelectric detectors is equal to the number of the spectral filters.

In one possible embodiment, the optical waveguide light homogenizer comprises a light guide member and a light homogenizing member;

the light guide component is used for transmitting an echo light signal from the spectral filter and transmitting the echo light signal to the dodging component; the light guide component is in a shape of a cylinder, a truncated cone, a cuboid or a prismatic table;

and the light homogenizing component is used for carrying out light homogenizing treatment on the echo light signals from the light guide component.

In one possible embodiment, the photodetector is an avalanche photodiode APD detector or a silicon photomultiplier SiPM detector.

In one possible embodiment, the method further comprises:

the collimating lens collimates the echo optical signal from the spatial filter and transmits the collimated echo optical signal to the angle filter;

the angle filter carries out angle filtering on the echo optical signal from the collimating lens and transmits the echo optical signal after the angle filtering to the focusing lens;

the focusing lens carries out focusing processing on the echo optical signals from the angle filter and transmits the echo optical signals after the focusing processing to the spectrum filter.

In one possible embodiment, the angular filter is a dow mirror.

In a possible embodiment, the focusing lens is in the shape of a spherical lens or a planar lens.

The embodiment of the present application and the embodiment of fig. 1 to 4 are based on the same concept, the technical effect thereof is the same as that of fig. 1 to 4, and the specific implementation process may refer to the description of the embodiment of fig. 1 to 4, which is not described herein again.

Those skilled in the art will clearly understand that the techniques in the embodiments of the present invention may be implemented by software plus necessary general hardware, including general purpose integrated circuits, general purpose CPUs, general purpose memories, general purpose components, etc., or by special purpose hardware, including special purpose integrated circuits, special purpose CPUs, special purpose memories, special purpose components, etc., but the former is a better implementation in many cases. Based on such understanding, the technical solutions in the embodiments of the present invention may be substantially implemented in the form of a software product, which may be stored in a storage medium, such as a Read-Only Memory (ROM), a random-access Memory (RAM), a magnetic disk, an optical disk, and the like, and includes several instructions for enabling a computer device (which may be a personal computer, a server, or a network device) to execute the method in each embodiment or some parts of the embodiments of the present invention.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system embodiment, since it is substantially similar to the method embodiment, the description is simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above-described embodiments of the present invention do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

A laser light receiving device, comprising: the system comprises a receiving objective lens, a spatial filter, a spectral filter and a photoelectric detector;

the receiving objective lens is used for receiving echo optical signals and transmitting the echo optical signals to the spatial filter;

the spatial filter is used for spatially filtering the echo optical signal from the receiving objective lens to filter noise optical signals outside a preset field of view, and transmitting the spatially filtered echo optical signal to the spectral filter;

the spectral filter is used for performing band-pass filtering on the echo optical signal from the spatial filter to filter noise optical signals outside a preset frequency band, and transmitting the echo optical signal subjected to the band-pass filtering to the photoelectric detector;

and the photoelectric detector is used for performing photoelectric conversion on the echo optical signal from the spectral filter to obtain an electric signal.
The laser light receiving device according to claim 1, further comprising:

and the optical waveguide dodging device is used for dodging the echo optical signals from the spectral filter and transmitting the dodged echo optical signals to the photoelectric detector.
The laser receiver according to claim 2, wherein the receiving objective adopts a telecentric beam path, and the optical waveguide homogenizer is arranged parallel to an optical axis of the receiving objective; or

The receiving objective adopts a non-telecentric light path, and the optical waveguide light equalizer and the optical axis of the receiving objective are arranged at a preset angle.
The laser receiving device according to claim 1, wherein the spatial filter includes a diaphragm, and the diaphragm is an aperture diaphragm, a field diaphragm, a vignetting diaphragm, or an anti-stray light diaphragm.
The laser light receiving device according to claim 4, wherein the diaphragm is disposed on a focal plane of the receiving objective lens.
The laser light receiving device according to claim 4, wherein an aperture size of the stop is θ × f, θ represents a divergence angle of the emitted light signal, and f represents a focal length of the receiving objective lens.
The laser receiving device according to claim 2 or 3, wherein the number of the optical waveguide dodging devices is plural, the plural optical waveguide dodging devices are arranged in M rows and N columns, M and N are integers greater than or equal to 1; the number of the photoelectric detectors is M multiplied by N, and the number of the spectral filters and the number of the optical waveguide dodging devices are M multiplied by N.
A laser receiving device according to claim 2 or 3, wherein the optical waveguide dodging device comprises: a light guide member and a light uniformizing member;

the light guide component is used for transmitting an echo light signal from the spectral filter and transmitting the echo light signal to the dodging component; the light guide component is in a shape of a cylinder, a truncated cone, a cuboid or a prismatic table;

and the light homogenizing component is used for carrying out light homogenizing treatment on the echo light signals from the light guide component.
The laser receiving device of claim 1, wherein the photodetector is an avalanche diode (APD) detector or a silicon photomultiplier detector.
The laser light receiving device according to claim 1, further comprising: a collimating lens, an angle filter and a focusing lens;

the collimating lens is used for collimating the echo optical signal from the spatial filter and transmitting the collimated echo optical signal to the angle filter;

the angle filter is used for carrying out angle filtering on the echo optical signals from the collimating lens and transmitting the echo optical signals after the angle filtering to the focusing lens;

the focusing lens is used for carrying out focusing processing on the echo optical signals from the angle filter and transmitting the echo optical signals after the focusing processing to the spectrum filter.
The laser receiver according to claim 10, wherein the angle filter is a dow mirror.
The laser light receiving device according to claim 10, wherein the focusing lens includes a plano-convex lens, a positive meniscus lens, an aspherical lens, a diffractive lens, or a reflective lens.
A laser receiving method, comprising:

the receiving objective lens receives an echo optical signal and transmits the echo optical signal to the spatial filter;

the spatial filter performs spatial filtering on the echo optical signal from the receiving objective lens to filter noise optical signals outside a preset field of view, and transmits the echo optical signal after the spatial filtering to the spectral filter;

the spectral filter is used for performing band-pass filtering on the echo optical signal from the spectral filter to filter noise optical signals outside a preset frequency band, and transmitting the echo optical signal subjected to band-pass filtering to the photoelectric detector;

and the photoelectric detector performs photoelectric conversion on the echo optical signal from the spectral filter to obtain an electric signal.
The method of claim 13, further comprising:

the optical waveguide dodging device conducts dodging processing on the echo optical signals from the spatial filter, and the echo optical signals after dodging processing are transmitted to the spectral filter.
A lidar, comprising: the laser light receiving device according to any one of claims 1 to 12.