1. An imaging principle based discrete atmospheric lidar system, comprising: a host and a receiver;

the receiver comprises a telescope and is detachably fixed on one side of the host;

the host comprises an emitting device, an emitting device fixing rotating plate and a bottom plate, wherein the emitting device is fixed on the emitting device fixing rotating plate, and the emitting device fixing rotating plate is rotatably connected with the bottom plate; the transmitting device is used for transmitting laser, and the overlapping area of the laser transmitted by the transmitting device and the telescope field of view changes along with the rotation of the fixed rotating plate of the transmitting device;

the transmitting device includes: a laser, a mirror, and a lens; laser beams emitted by the laser are reflected by the reflecting mirror and then are collimated by the lens and then are emitted, and an included angle between an incident light path of the reflecting mirror and a light path emitted by the reflecting mirror meets a set range.

2. The imaging-principle-based discrete atmospheric lidar system of claim 1, wherein the number of lasers is plural, each of the lasers emitting a laser beam of a different wavelength; the emitting device also comprises light splitting sheets, and laser beams emitted by the lasers are combined into one beam through the light splitting sheets to irradiate the reflecting mirror.

3. The imaging-principle-based discrete atmospheric lidar system of claim 2, wherein the receiver further comprises a plurality of cameras and a plurality of optical filters, the cameras and the optical filters are in one-to-one correspondence, the corresponding optical filters are arranged in front of the light-sensing elements of the cameras, and the wavelength band through which each optical filter can pass corresponds to the wavelength of the laser beam emitted by each laser.

4. The imaging-principles-based discrete atmospheric lidar system of claim 1, wherein the number of lasers is 1; the receiver comprises 1 camera and 1 optical filter; the camera corresponds to the optical filter, the optical filter is arranged in front of a photosensitive element of the camera, and the wavelength band through which the optical filter can pass corresponds to the wavelength of the laser beam emitted by the laser.

5. The imaging-principles-based discrete atmospheric lidar system of claim 1, wherein the mainframe further comprises a rotating platform, and the transmitting device stationary rotating plate is mounted on the base plate via the rotating platform.

6. The imaging-principles-based discrete atmospheric lidar system of claim 1, wherein the mainframe further comprises a rotating shaft fixed to the base plate, the transmitting device fixed rotating plate being rotatably coupled to the rotating shaft, the transmitting device fixed rotating plate being rotatable about the rotating shaft.

7. The imaging-principles-based discrete atmospheric lidar system of claim 1, wherein the transmitting device further comprises a light shield for shielding an area through which the laser path passes.

8. The imaging-principles-based discrete atmospheric lidar system of claim 1, wherein the transmitting device further comprises a transmitting barrel and an adjustable device, the lens being vertically disposed within the transmitting barrel via the adjustable device, the adjustable device being configured to adjust a distance between the lens and the laser.

9. The imaging-principle-based discrete atmospheric lidar system of claim 1, wherein the host comprises a master control device and a drive device; the main control device is arranged on the bottom plate, is respectively in control connection with the transmitting device and the receiving device, and is used for controlling the transmitting device and the receiving device to work cooperatively to complete data acquisition and data storage; the driving device is fixed on the bottom plate, is respectively connected with the main control device, the transmitting device and the receiver, and is used for outputting a driving signal according to a control signal sent by the main control device and sending the driving signal to the transmitting device and the receiver.

10. The imaging-principles-based discrete atmospheric lidar system of claim 1, further comprising a housing, the host and the receiver being disposed within the housing; the housing is provided with a window sheet, and the laser beam penetrates through the window sheet to be emitted.

Background

Aerosol refers to the general term of liquid or solid particles suspended in the atmosphere, and although the content of the particles in the whole atmospheric environment is small, the aerosol has vital influence on human health, public health and even environmental climate. Therefore, the detection of the spatial and temporal distribution of the optical and micro-physical properties of atmospheric aerosols is of great significance for the study of regional and global environmental and climatic problems. Due to the size range limitation of aerosol particles, active remote sensing technology for atmospheric aerosol detection generally refers to a laser radar with a laser as a radiation source. At present, the atmospheric aerosol laser radar generally has the problems of large volume, complex adjustment, difficult portability, difficult movement and the like, a receiving telescope arranged in a laser radar system has large volume, and the telescope is fixed in the laser radar system and is difficult to disassemble; the divergence angle of the laser beam emitted by the laser in the laser radar system needs to be matched with the receiving angle of the lens, so that the laser radar system has distance requirements on the light path of the laser emitted by the laser, and the parts forming the laser radar system are fixed inside the radar system, so that the laser radar for detecting the atmospheric aerosol is large in size and inconvenient for frequently replacing the measuring field.

Disclosure of Invention

The invention aims to provide an atmospheric lidar system which is smaller in size and more portable.

In order to achieve the purpose, the invention provides the following scheme:

a discrete atmospheric lidar system based on imaging principles comprises: a host and a receiver;

the receiver comprises a telescope and is detachably fixed on one side of the host;

the host comprises an emitting device, wherein the emitting device fixes a rotating plate and a bottom plate, the emitting device is fixed on the emitting device fixing rotating plate, and the emitting device fixing rotating plate is rotatably connected with the bottom plate; the transmitting device is used for transmitting laser, and the overlapping area of the laser transmitted by the transmitting device and the telescope field of view changes along with the rotation of the fixed rotating plate of the transmitting device;

the transmitting device includes: a laser, a mirror, and a lens; laser beams emitted by the laser are reflected by the reflecting mirror and then emitted from the lens, and an included angle between an incident light path of the reflecting mirror and a light path emitted by the reflecting mirror meets a set range.

Optionally, the number of the lasers is multiple, and each of the lasers emits a laser beam with a different wavelength; the emitting device also comprises light splitting sheets, and laser beams emitted by the lasers are combined into one beam through the light splitting sheets to irradiate the reflecting mirror.

Optionally, the receiver further includes a plurality of cameras and a plurality of optical filters, the cameras and the optical filters correspond to each other one by one, the corresponding optical filters are disposed in front of a light sensing element of the cameras, and a wavelength band allowed by each optical filter corresponds to a wavelength of a laser beam emitted by each laser.

Optionally, the host computer further includes a rotating platform, and the transmitting device fixing rotating plate is mounted on the bottom plate through the rotating platform.

Optionally, the host further includes a rotating shaft fixed on the bottom plate, the transmitting device fixing rotating plate is rotatably connected to the rotating shaft, and the transmitting device fixing rotating plate can rotate around the rotating shaft.

Optionally, the emitting device further includes a light shielding cylinder for shielding a region through which the laser path passes.

Optionally, the emitting device further includes an emitting barrel and an adjustable device, the lens is vertically disposed in the emitting barrel through the adjustable device, and the adjustable device is used for adjusting a distance between the lens and the laser.

Optionally, the host includes a master control device, the master control device is installed on the bottom plate, is respectively in control connection with the transmitting device and the receiving device, and is used for controlling the transmitting device and the receiving device to cooperatively work to complete data acquisition and data storage.

Optionally, the host further includes a driving device, the driving device is fixed on the bottom plate, and is respectively connected to the main control device, the transmitting device and the receiver, and is configured to output a driving signal according to a control signal sent by the main control device, and send the driving signal to the transmitting device and the receiver.

Optionally, the atmospheric lidar system further includes a housing, and the host is disposed in the housing; the housing is provided with a window sheet, and the laser beam penetrates through the window sheet to be emitted.

According to the specific embodiment provided by the invention, the invention discloses the following technical effects: a discrete atmospheric lidar system based on imaging principles comprises: a host and a receiver; the receiver comprises a telescope and a control unit, wherein the telescope is detachably fixed on one side of the host; the host comprises an emitting device, an emitting device fixing rotating plate and a bottom plate, wherein the emitting device is fixed on the emitting device fixing rotating plate, and the emitting device fixing rotating plate is rotatably connected with the bottom plate; the transmitting device is used for transmitting laser, and the overlapping area of the laser transmitted by the transmitting device and the telescope field of view changes along with the rotation of the fixed rotating plate of the transmitting device; the transmitting device includes: a laser, a mirror, and a lens; laser beams emitted by the laser are reflected by the reflecting mirror and then emitted from the lens, and the included angle between the incident light path of the reflecting mirror and the light path emitted by the reflecting mirror meets the set range. According to the invention, the reflector is arranged, so that a laser beam emitted by the laser is reflected by the reflector and then emitted from the lens, and an included angle is formed between an incident light path of the reflector and a light path emitted by the reflector, so that the effect of folding the light path of the laser is realized, the structure of the system is more compact, meanwhile, the system adopts a structure that a host is used for mounting a receiver, the receiver is convenient to disassemble and replace, and the purposes of smaller volume and more portability of an atmospheric laser radar system are realized; the transmitting device is arranged on the transmitting device fixing rotating plate, and after the laser, the reflecting mirror and the lens are arranged, the center of the reflecting mirror is directly aligned with the center of the optical axis of the lens; after the lens is focused, the position of the lens is also fixed; when the overlapping area of the laser emitted by the emitting device and the telescope field of view is adjusted, only the fixed rotating plate of the emitting device needs to be rotated, and the single component in the emitting device is not adjusted, so that the aim of convenient adjustment is fulfilled; when the atmospheric aerosol is detected, the receiver only needs to receive the back scattering light of the laser beam in the overlapping area of the laser emitted from the emitting device and the telescope visual field, so that the atmospheric aerosol is sampled, and the effect of simple and convenient sampling is further realized.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used 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 inventive exercise.

FIG. 1 is a schematic diagram of a dual laser and dual camera configuration of a discrete atmospheric lidar system of the present invention based on the imaging principle;

FIG. 2 is a schematic diagram of a single laser and a single camera of the discrete atmospheric lidar system based on imaging principles of the present invention;

fig. 3 is a schematic structural diagram of the housing of the discrete atmospheric lidar system based on the imaging principle.

Description of the symbols:

a first diode laser-1, a first cage cube-2, a first beam splitter-3, a cage cube fixing base-4, a cone shade tube-5, a total reflection mirror-6, an emission tube-7, a lens-8, a lens fixing tube-9, a main body visor-10, a second diode laser-11, an emission device fixing rotation plate-12, a driving device-13, a receiver fixing base-14, a telescope-15, a second beam splitter-16, a first optical filter mounting base-17, a first optical filter-18, a first area array camera-19, a second cage cube-20, a second optical filter mounting base-21, a second optical filter-22, a second area array camera-23, a camera fixing base-24, an industrial personal computer-25, a direct current voltage conversion module-26, an aviation socket-27, a base plate-28, a rotation shaft-29, a diode laser-30, a cage cube-31, a beam splitter 32, a rotary platform 33, an observation camera 34, a narrow band filter 35, an area-array camera 36, a shell 37 and a window 38.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a discrete atmospheric lidar system which is smaller in size and more portable and is based on an imaging principle.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

The discrete atmospheric lidar system based on the imaging principle provided by the embodiment of the invention comprises: a host and a receiver; the receiver comprises a telescope 15, and the receiver is detachably fixed on one side of the host; the main machine comprises an emitting device, an emitting device fixing rotating plate 12 and a bottom plate 28, wherein the emitting device is fixed on the emitting device fixing rotating plate 12, and the emitting device fixing rotating plate 12 is rotatably connected with the bottom plate 28; the transmitting device is used for transmitting laser, and the overlapping area of the laser transmitted by the transmitting device and the view field of the telescope 15 changes along with the rotation of the fixed rotating plate 12 of the transmitting device; the transmitting device includes: a laser, mirror and lens 8; laser beams emitted by the laser are reflected by the reflecting mirror and then emitted from the lens 8, and the included angle between the incident light path of the reflecting mirror and the light path emitted by the reflecting mirror meets the set requirement.

Example 1

As shown in fig. 1, the number of the lasers is plural, and each laser emits a laser beam with a different wavelength; the transmitting device also comprises light splitting sheets, and laser beams emitted by the lasers are combined into one beam through the light splitting sheets to irradiate the reflecting mirror; the discrete atmospheric lidar system based on the imaging principle further comprises a cage cube and a cage cube fixing seat 4.

Specifically, the cage cube comprises a first cage cube 2 and a second cage cube 20, and the first cage cube 2 is fixed on the launching device fixing rotating plate 12 through the cage cube fixing seat 4; the light splitting sheets include a first light splitting sheet 3 and a second light splitting sheet 16; the first light splitting sheet 3 and the side surface of the first cage cube 2 form an included angle of 45 degrees and are vertically arranged in the first cage cube 2 together with the bottom surface of the first cage cube 2; the laser is a diode laser. The laser comprises a first diode laser 1 and a second diode laser 11, wherein the first diode laser 1 and the second diode laser 11 are respectively arranged on two sides of the first cage cube 2 and fixed on the transmitting device fixing rotating plate 12.

Further, the first diode laser 1 and the second diode laser 11 emit laser beams with different wavelengths, two laser beams with different wavelengths are combined into one laser beam by the first light splitter 3 after passing through the first light splitter 3 in the first cage cube 2, the one laser beam enters the reflector, after being reflected by the reflector, the one laser beam is folded to change the light path direction of the laser beam, and the laser beam reflected by the reflector is emitted to the lens 8 through the emitting tube 7 and is emitted to the atmosphere through the lens 8. The preferred mirror is a 45 ° total reflection mirror 6.

The emitting device also comprises an emitting barrel 7 and an adjustable device, the lens 8 is vertically arranged in the emitting barrel 7 through the adjustable device, and the adjustable device is used for adjusting the distance between the lens 8 and the laser; the transmitting device also comprises a shading cylinder, wherein the shading cylinder is used for shading the area through which the laser path passes; the transmitting device is arranged on the transmitting device fixing rotating plate 12, and after the laser, the reflecting mirror and the lens 8 are arranged, the center of the reflecting mirror is directly aligned with the center of the optical axis of the lens 8; after the lens 8 is focused, the position of the lens 8 is also fixed; preferably, the light shielding cylinder is a cone-shaped light shielding cylinder 5. The total reflector 6 and the conical shading cylinder 5 are fixedly connected with the transmitting cylinder 7.

Specifically, the adjustable device is a lens fixing barrel 9, the lens 8 is placed in the lens fixing barrel 9, and the lens 8 is fixed by screwing a snap ring into the lens fixing barrel 9 through threads. When the laser beam is collimated by the lens 8, the distance between the lens 8 and the first diode laser 1 and the second diode laser 11 can be adjusted only by rotating the screw thread in the lens fixing barrel 9, so that the positions of the first diode laser 1 and the second diode laser 11 are prevented from being adjusted, and the whole transmitting device is more stable.

Further, the distance between the first diode laser 1 and the second diode laser 11 and the lens 8 is adjusted, when the laser beams emitted to the atmosphere are highly parallel, the judgment standard is that the laser beams can present clear laser spots on buildings with the distance of more than 2km, and the distance between the first diode laser 1 and the second diode laser 11 and the lens 8 is adjusted.

Further, when the emitting device is fixedly installed, the positional relationship among the first diode laser 1, the first cage cube 2, the total reflection mirror 6, and the lens 8 satisfies: the center of the first diode laser 1, the center of the first cage cube 2, and the center of the total reflection mirror 6 are located on a straight line, the straight line is perpendicular to a connecting line between the center of the second diode laser 11 and the center of the first cage cube 2, the straight line is perpendicular to the optical axis of the lens 8, and the centers of the above parts are on the same plane and parallel to the bottom plate 28. After the first diode laser 1, the second diode laser 11, the cage cube 31 and the total reflection mirror 6 are installed and fixed, the positions cannot be adjusted. The distance between the lens 8 and the first diode laser 1 and the second diode laser 11 can be adjusted only by rotating the screw thread in the lens fixing barrel 9, so that the laser beams emitted from the first diode laser 1 and the second diode laser 11 can be collimated and emitted out after passing through the center of the first cage cube 2, the center of the total reflection mirror 6 and the center of the lens 8.

The main body further includes a rotation shaft 29, the rotation shaft 29 being fixed to the base plate 28, the transmitting device fixed rotation plate 12 being rotatably coupled to the rotation shaft, the transmitting device fixed rotation plate 12 being rotatable about the rotation shaft 29.

Specifically, when the area through which the laser beam emitted by the emitting device passes is adjusted, the emitting device fixing rotating plate 12 only needs to rotate around the rotating shaft 29, and after the adjustment is completed, the emitting device fixing rotating plate 12 is fixed on the bottom plate 28 through screws, so that the structural stability of the laser emitting device is ensured.

The host comprises a main control device and a driving device 13, the main control device and the driving device 13 are installed on the bottom plate 28, and the main control device is respectively in control connection with the transmitting device and the receiving device and is used for controlling the transmitting device and the receiving device to work cooperatively to complete data acquisition and data storage; the driving device 13 is connected to the main control device, the transmitting device and the receiver, respectively, and is configured to output a driving signal according to a control signal sent by the main control device, and send the driving signal to the transmitting device and the receiver.

The host further comprises a direct current voltage conversion module 26 and an aviation socket 27, wherein the direct current voltage conversion module 26 is used for converting input direct current into voltage matched with an industrial personal computer, a driving device and the like, and the aviation socket 27 is used for simultaneously connecting a plurality of driving circuits for power supply.

The receiver also comprises a plurality of cameras and a plurality of optical filters, the cameras and the optical filters are in one-to-one correspondence, the corresponding optical filters are arranged in front of the photosensitive elements of the cameras, and the wave bands through which the optical filters can pass correspond to the wavelengths of the laser beams emitted by the lasers.

Specifically, the cameras are area-array cameras and include a first area-array camera 19 and a second area-array camera 23, and the optical filters are narrow-band optical filters and include a first optical filter 18 and a second optical filter 22. A first optical filter 18 is arranged in front of the light sensing element of the first area-array camera 19, and a second optical filter 22 is arranged in front of the light sensing element of the second area-array camera 23.

The main control device mainly comprises an industrial personal computer 25, the working current and the temperature of the laser are controlled through serial port communication, and the transmission and the storage of image data collected by the camera can be realized through a data connecting line.

The driving device 13 mainly includes a temperature control circuit, a current driving circuit and a trigger signal modulation circuit of the first diode laser 1 and the second diode laser 11, the circuits are fixed on the bottom plate 28, the temperature control circuit is used for controlling the working temperature of the first diode laser 1 and the working temperature of the second diode laser 11, the current driving circuit is used for controlling the input current of the first diode laser 1 and the input current of the second diode laser 11, and the trigger signal modulation circuit can modulate and output the trigger signal output by the first area array camera 19 or the second area array camera 23.

Further, after the industrial personal computer 25 controls the first area-array camera 19 and the second area-array camera 23 to start image acquisition, the trigger signal of the first area-array camera 19 is modulated by the trigger signal modulation circuit and then input to the current driving circuit, and the first diode laser 1 and the second diode laser 11 are driven to realize synchronous 'on-off' intensity modulation. Meanwhile, the second area-array camera 23 is matched with the trigger signal of the first area-array camera 19 through the control program of the industrial personal computer 25, so that the first area-array camera 19 and the second area-array camera 23 synchronously acquire images.

Furthermore, the receiver further comprises a first filter mounting seat 17, a second filter mounting seat 21, a receiver fixing frame 14 and a camera fixing seat 24. The telescope 15 is connected with a host through the receiver fixing frame 14, the focusing of the telescope 15 is adjusted through a knob, the second cage cube 20 is fixed on the receiver fixing frame 14 through the camera fixing seat 24, the center of the second cage cube 20 and the optical axis of the telescope 15 are on the same straight line, the second light splitter 16 is installed inside the second cage cube 20, the center line of the second light splitter 16 and the optical axis of the telescope 15 form an angle of 45 degrees, the first light filter installation seat 17 and the second light filter installation seat 21 are respectively installed on two sides of the second cage cube 20, the first light filter 18 is installed inside the first light filter installation seat 17, the second light filter 22 is installed inside the second light filter installation seat 21, the first area array camera 19 is fixed on one side of the first light filter installation seat 17, and the second area array camera 23 is fixed on one side of the second light filter installation seat. Specifically, the receiver is fixed on one side of the host in a mounting mode; more specifically, the receiver fixing frame 14 is fixed on the host machine through a snap fit screw, and is convenient to mount and stable in structure.

Because the transmitting device is installed on the transmitting device fixing rotating plate 12, after the first diode laser 1, the second diode laser 11, the first light splitter 3, the total reflection mirror 6 and the lens 8 are installed, the centers of the first diode laser 1, the first light splitter 3 and the total reflection mirror 6 are on a straight line, the straight line is vertical to a connecting line of the center of the second diode laser 11 and the center of the first cage cube 2, meanwhile, the straight line is vertical to the optical axis of the lens 8, the centers of the above parts are on the same plane and are parallel to the bottom plate 28, the center of the total reflection mirror 6 is directly aligned to the center of the optical axis of the lens 8, after the lens 8 is focused, the position of the lens 8 is also fixed, the positions of the components in the transmitting device on the transmitting device fixing rotating plate 12 are fixed, the overlapping of the laser emitted by the transmitting device and the view field of the telescope 15 can be realized only by rotating the transmitting device fixing rotating plate 12, the adjustment of the individual components in the transmitting device is no longer performed, so that the aim of convenient adjustment is achieved.

The area-array camera, the telescope 15 and the laser emitting device satisfy any one of the following positional relationships: (1) the plane of the sensor of the area-array camera, the plane of the equivalent lens 8 of the laser receiving device and the optical axis of the laser emitting device are intersected, so that the Sabourdon imaging principle is satisfied; (2) the plane of the sensor of the area-array camera is placed in parallel at the focus of the telescope 15. In both of the above two positional relationships, the pixel-distance relationship can be calculated by geometric optics.

Preferably, the wavelength of the first diode laser 1 is 450nm, and the wavelength of the second diode laser 11 is 808 nm; the transmission center wavelength of the first optical filter 18 is consistent with the working wavelength of the first diode laser 1; the transmission center wavelength of the second filter 22 coincides with the operating wavelength of the second diode laser 11.

Preferably, the area-array camera is a front-illuminated area-array camera, a back-illuminated area-array camera or a polarized area-array camera.

Preferably, the distance between the center of the lens 8 in the transmitting device and the center of the lens 8 of the telescope 15 is not more than 1 meter.

As shown in fig. 3, the discrete atmospheric lidar system based on imaging principle provided by the present embodiment further includes a housing 37, and the host and the receiver are disposed in the housing 37; a window piece 38 is provided on the housing 37, and the laser beam is emitted through the window piece 38; the shell 37 is further provided with a host hat brim 10, the host hat brim 10 is arranged above the window sheet 38, and the window sheet 38 and the host hat brim 10 are used for realizing the functions of shading, dust prevention and rain prevention of the laser emission window.

The operation of the discrete atmospheric lidar system based on imaging principle provided by this embodiment will be described below.

When the system pixel-distance relationship is calibrated, a remote building is selected as a pixel-distance relationship calibration point, laser is emitted to the selected building, the pixel point of the building imaged on the area-array camera and the known distance between the system and the building are obtained, and the one-to-one corresponding relationship between each pixel and the distance is calculated through the geometrical optical relationship;

when the system is used for atmospheric measurement, after two beams of laser with different wavelengths emitted into the atmosphere by a first diode laser and a second diode laser are absorbed and scattered by atmospheric particulates, backscattered light of laser beams is collected by a telescope, split by a beam splitter, and then respectively imaged on a first area-array camera and a second area-array camera after atmospheric background signals are filtered by a first optical filter and a second optical filter, finally image data are transmitted into an industrial personal computer, a laser radar signal with pixel-intensity can be obtained by deducting, longitudinally accumulating and averaging the background of a beam image, and an atmospheric laser radar signal with distance-intensity of two wavelengths can be obtained by pixel-distance conversion. The optical or micro-physical characteristics of particles such as extinction coefficient, backscattering coefficient, particle size and the like of the atmospheric aerosol can be obtained through algorithm inversion.

The first diode laser and the second diode laser are used as emitting light sources, the first area array camera and the second area array camera are used as receiving detectors, and detection of particle concentration, form and size can be achieved in an imaging mode.

Example 2

As shown in fig. 2, the number of lasers is 1; the emitting device further comprises a viewing camera 34 and a beam splitter 32, and the laser beam emitted by the laser is directed to the reflector through the beam splitter 32. The discrete atmospheric lidar system based on the imaging principle further comprises a cage cube 31 and a cage cube fixing seat 4.

Specifically, the cage cube 31 is fixed on the launching device fixing rotating plate 12 through the cage cube fixing seat 4; the light splitting sheet 32 and the side surface of the cage cube 31 form an included angle of 45 degrees and are vertically arranged in the cage cube 31 together with the bottom surface of the cage cube 31; the laser is a diode laser 30; the diode laser 30 is arranged at one side of the cage cube 31 and fixed on the emitter fixing rotation plate 12; the observation camera 34 is disposed at the other side of the cage cube 31 and fixed to the transmission device fixing rotation plate 12.

Further, the laser beam emitted by the diode laser 30 passes through the beam splitter 32 in the cage cube 31 and then enters the reflector, after being reflected by the reflector, the light path of the laser beam is folded to change the light path direction of the laser beam, and the laser beam reflected by the reflector is emitted to the lens 8 through the emission tube 7 and then emitted to the atmosphere through the lens 8. The preferred mirror is a 45 ° total reflection mirror 6.

The emitting device further comprises an emitting barrel 7 and an adjustable device, the lens 8 is vertically arranged in the emitting barrel 7 through the adjustable device, and the adjustable device is used for adjusting the distance between the lens 8 and the laser. The light shielding cylinder 5 is used for shielding the area through which the laser path passes; the transmitting device is arranged on the transmitting device fixing rotating plate 12, and after the laser, the reflecting mirror and the lens 8 are arranged, the center of the reflecting mirror is directly aligned with the center of the optical axis of the lens 8; after the lens 8 is focused, the position of the lens 8 is also fixed; preferably, the light shielding cylinder 5 is a tapered light shielding cylinder. The total reflector 6 and the conical shading cylinder are fixedly connected with the transmitting cylinder 7.

Specifically, the adjustable device is a lens fixing barrel 9, the lens 8 is placed in the lens fixing barrel 9, and the lens 8 is fixed by screwing a snap ring into the lens fixing barrel 9 through threads. When the laser beam is collimated by the lens 8, the distance between the lens 8 and the diode laser 30 can be adjusted by rotating the screw thread in the lens fixing barrel 9, so that the position of the diode laser 30 is prevented from being adjusted, and the whole emitting device is more stable.

Further, the distance between the diode laser 30 and the lens 8 is adjusted, when the laser beam emitted to the atmosphere is highly parallel, the judgment standard is that the laser beam can present clear laser spots on buildings with a distance of more than 2km, and the distance between the diode laser 30 and the observation camera 34 and the lens 8 is adjusted.

Further, when the emitting device is fixedly installed, the positional relationship among the diode laser 30, the cage cube 31, the total reflection mirror 6 and the lens 8 satisfies: the center of the diode laser 30, the center of the cage cube 31, and the center of the total reflection mirror 6 are located on a straight line perpendicular to the optical axis of the lens 8, and the centers of the above parts are on the same plane and parallel to the bottom plate 28. After the diode laser 30, the cage cube 31 and the total reflection mirror 6 are installed and fixed, the positions cannot be adjusted. The distance between the lens 8 and the diode laser 30 can be adjusted by only rotating the screw thread in the lens fixing cylinder 9, so that the laser beam emitted by the diode laser 30 can be collimated and emitted through the center of the cage cube 31, the center of the total reflection mirror 6 and the center of the lens 8.

The main machine also comprises a rotating platform 33, and the fixed rotating plate 12 of the launching device is arranged on the bottom plate 28 through the rotating platform 33; the rotary platform 33 is divided into an upper layer and a lower layer which are tightly connected, the lower layer of the rotary platform 33 is directly fixed on the bottom plate 28, the upper layer of the rotary platform 33 is fixed with the transmitting device fixed rotary plate 12, and the upper layer of the rotary platform 33 can be rotated through the fine adjustment knob.

Specifically, when the region through which the laser beam emitted by the emitting device passes is adjusted, only the fine adjustment knob needs to be twisted, the emitting device fixing rotating plate 12 fixed on the upper layer of the rotating platform 33 can rotate around the center of the rotating platform 33, after the adjustment is completed, the plurality of screws are screwed, the upper layer of the rotating platform 33 and the emitting device fixing rotating plate 12 fixed on the upper layer of the rotating platform 33 can be fixed on the lower layer of the rotating platform 33 together, and the lower layer of the rotating platform 33 is fixed on the bottom plate 28, so that the emitting device fixing rotating plate 12 is also fixed on the bottom plate 28, and the stable structure of the laser emitting device is ensured.

The host comprises a main control device and a driving device 13, the main control device and the driving device 13 are installed on the bottom plate 28, and the main control device is respectively in control connection with the transmitting device and the receiving device and is used for controlling the transmitting device and the receiving device to work cooperatively to complete data acquisition and data storage; the driving device 13 is connected to the main control device, the transmitting device and the receiver, respectively, and is configured to output a driving signal according to a control signal sent by the main control device, and send the driving signal to the transmitting device and the receiver.

The receiver also comprises a camera and optical filters, the camera corresponds to the optical filters one to one, the corresponding optical filters are arranged in front of the photosensitive elements of the camera, and the wave bands allowed by the optical filters correspond to the wavelengths of the laser beams emitted by the laser.

Specifically, the camera is an area-array camera 36, and the filter is a narrow-band filter 35. A narrow-band filter 35 is arranged in front of the photosensitive element of the area-array camera 36.

The main control device mainly comprises an industrial personal computer 25, the working current and the temperature of the laser are controlled through serial port communication, and the transmission and the storage of image data collected by the camera can be realized through a data connecting line.

The driving device 13 mainly includes a temperature control circuit of the diode laser 30, a current driving circuit, and a trigger signal modulation circuit, the circuits are fixed on the bottom plate 28, the temperature control circuit is used to control the working temperature of the diode laser 30, the current driving circuit is used to control the current input to the diode laser 30, and the trigger signal modulation circuit can modulate the trigger signal input to the area array camera 36 and output the modulated trigger signal.

Further, after the industrial personal computer 25 controls the area array camera 36 to start image acquisition, the trigger signal of the area array camera 36 is modulated by the trigger signal modulation circuit and then input to the current driving circuit, and the diode laser 30 is driven to realize on-off intensity modulation and is synchronous with the trigger signal of the area array camera 36.

Further, the receiver further includes a receiver holder 14 and a camera holder 24. The telescope 15 is connected with the host computer through the receiver mount 14, and the focusing of telescope 15 is adjusted through the knob, and area array camera 36 is connected with telescope 15 through camera fixing base 24, and narrowband optical filter 35 installs inside camera fixing base 24, and camera fixing base 24 is fixed on receiver mount 14. Specifically, the receiver is fixed on one side of the host in a mounting mode; more specifically, the receiver fixing frame 14 is fixed on the host machine through a snap fit screw, and is convenient to mount and stable in structure.

Because the transmitting device is installed on the transmitting device fixed rotating plate 12, after the diode laser 30, the beam splitter 32, the total reflection mirror 6 and the lens 8 are installed, the centers of the diode laser 30, the beam splitter 32 and the total reflection mirror 6 are on a straight line, meanwhile, the straight line is perpendicular to the optical axis of the lens 8, the centers of the above parts are on the same plane and are parallel to the bottom plate 28, the center of the total reflection mirror 6 is directly aligned to the center of the optical axis of the lens 8, after the lens 8 is focused, the position of the lens 8 is also fixed, the positions of the components in the transmitting device on the transmitting device fixed rotating plate 12 are all fixed, the overlapping of the visual fields of the laser transmitted by the transmitting device and the telescope 15 can be realized only by rotating the transmitting device fixed rotating plate 12, the adjustment of the single component in the transmitting device is not required, and the purpose of convenient adjustment is realized.

The area-array camera 36, the telescope 15 and the laser transmitter satisfy any one of the following positional relationships: (1) the plane of the sensor of the area-array camera 36, the plane of the equivalent lens 8 of the laser receiving device and the optical axis of the laser emitting device are intersected to meet the Shaw imaging principle; (2) the plane of the sensor of the area-array camera 36 is placed parallel to the focal point of the telescope 15. In both of the above two positional relationships, the pixel-distance relationship can be calculated by geometric optics.

Optionally, the wavelength of the diode laser 30 is 405nm, 450nm, 520nm, or 808 nm; the transmission center wavelength of the narrowband filter 35 coincides with the operating wavelength of the diode laser 30.

Optionally, the telescope 15 is a telescope with a large focal ratio, and further, the telescope 15 may be a maca telescope, a schka telescope, a bovine reflex telescope or a refractive telescope.

Optionally, the area-array camera 36 is a high-speed area-array camera, an industrial area-array camera, or a polarization area-array camera.

As shown in fig. 3, the discrete atmospheric lidar system based on imaging principles further comprises a housing 37, the host and the receiver being arranged within the housing 37; a window piece 38 is provided on the housing 37, and the laser beam is emitted through the window piece 38; the shell 37 is further provided with a host hat brim 10, the host hat brim 10 is arranged above the window sheet 38, and the window sheet 38 and the host hat brim 10 are used for realizing the functions of shading, dust prevention and rain prevention of the laser emission window.

The operation of the discrete atmospheric lidar system based on imaging principle provided by this embodiment will be described below.

When the system is adjusted, the diode laser is closed, external scattered light is collected through the lens, enters the shading cylinder through the emission cylinder and reflected by the holophote, and is split and converged on a photosensitive element of the observation camera through the beam splitter in the cage type cube; meanwhile, the outside scattered light is collected by a telescope of the receiver, part of the scattered light is filtered by a narrow-band filter, and finally the rest scattered light is converged on a photosensitive element of the area-array camera. The rotary platform is adjusted through the fine adjustment knob, the swing angle of the emitting device can be accurately adjusted, and then the view field of the laser emitting device can be adjusted, so that the observation view field of the observation camera and the observation view field of the area array camera are kept consistent.

When the system pixel-distance relationship is calibrated, a remote building is selected as a pixel-distance relationship calibration point, laser is emitted to the selected building, the pixel point of the building imaged on the area-array camera and the known distance between the system and the building are obtained, and the one-to-one corresponding relationship between each pixel and the distance is calculated through the geometrical optical relationship; preferably, the laser beam is emitted onto a tall building of more than 2 km.

When the system is used for measuring the atmosphere, laser emitted into the atmosphere by a diode laser is absorbed and scattered by atmospheric aerosol and gas molecules, backward scattered light of a laser beam is collected by a telescope, most of solar background light is filtered by a narrow-band filter, the atmospheric laser beam is detected by an area array camera and image data is transmitted to an industrial personal computer, background subtraction, longitudinal accumulation and median average of a beam image are realized by the industrial personal computer to obtain a pixel-intensity laser radar signal, and a distance-intensity atmospheric laser radar signal can be obtained by pixel-distance conversion. The optical or micro-physical characteristics of particles such as extinction coefficient, backscattering coefficient and the like of the atmospheric aerosol can be obtained through algorithm inversion.

According to the invention, the reflector is installed, so that a laser beam emitted by the laser is emitted after being reflected by the reflector and collimated by the lens, an included angle is formed between an incident light path of the reflector and a light path emitted by the reflector, the effect of folding the light path of the laser is realized, and the structure of the system is more compact; the transmitting device is arranged on the transmitting device fixing rotating plate, after the laser, the reflecting mirror and the lens are arranged, the center of the reflecting mirror is directly aligned to the center of the optical axis of the lens, the position of the lens is also fixed after the lens is focused, and when the overlapping area of the laser transmitted by the transmitting device and the field of view of the telescope is adjusted, only the transmitting device fixing rotating plate needs to be rotated, and the single component in the transmitting device is not adjusted, so that the aim of convenient adjustment is fulfilled; when the atmospheric aerosol is detected, the receiver only needs to receive the back scattering light of the laser beam in the overlapping area of the laser emitted from the emitting device and the telescope visual field, so that the atmospheric aerosol is sampled, and the effect of simple and convenient sampling is further realized.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description.

The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.