CN104765160B - A kind of light beam bearing calibration system and calibration method - Google Patents

Abstract

The invention discloses a light beam orientation calibration system, which includes a first optical mirror, a second optical mirror, a third optical mirror, a fourth optical mirror and an optical wedge. After the light beam is reflected by the first optical mirror and the second optical mirror successively, Pass above or below the fourth optical mirror, and after being reflected by the third optical mirror and the fourth optical mirror, shoot from below or above the third optical mirror to the optical wedge, and the two reflective surfaces of the optical wedge are inclined to the direction of the incident light beam ; including two light receiving devices for receiving light beams reflected by the two reflective surfaces of the optical wedge; the second optical mirror and the fourth optical mirror are adjustable optical mirrors. The invention also discloses a calibration method of the calibration system. The beam calibration system and calibration method of the present invention have the function of automatic real-time calibration of the beam orientation, and can be used as a front-end system of various laser precision application systems. The application of this system can record the state of the normal working optical path and realize fast and accurate optical path recovery.

Description

A beam orientation calibration system and calibration method

technical field

The invention belongs to the field of optoelectronic technology, and in particular relates to a beam orientation calibration system and a calibration method thereof.

Background technique

In the application field of laser technology, such as free space optical communication, laser precision measurement, laser biomedicine and other application fields, there are high requirements for the direction and orientation stability of the laser beam.

For precise laser applications, due to the temperature deformation of the laser resonator, the instability of optical components on the transmission path, and the influence of various environmental disturbances, the laser beam will always have a small amount of azimuth deviation, including angular deviation and parallel deviation. shift. When the offset is large, it will seriously affect the working stability of the subsequent system.

In addition, in actual work, it is often necessary to restore the optical path of the optical system in a changed working environment. For a large optical system, accurate optical path restoration is very time-consuming and labor-intensive.

How to effectively calibrate the optical system conveniently, quickly and accurately has always been the focus and focus of research in the field of laser technology application or opto-mechanical technology. In the existing technical solutions for beam orientation calibration, precision and convenience cannot be achieved at the same time. Although complex optical systems are accurate, they usually cannot quickly and easily calibrate or restore the optical path, and the cost is generally high; simple Although the optical system takes the latter into account, it is often not precise enough. Existing solutions greatly restrict the application of lasers in fields with precise pointing requirements.

Contents of the invention

The purpose of the present invention is to solve the above problems and provide a new beam calibration system and calibration method.

One of the technical solutions adopted to achieve the purpose of the present invention is: a beam orientation calibration system, including a first optical mirror, a second optical mirror, a third optical mirror, a fourth optical mirror and an optical wedge, and the beam successively passes through the first After being reflected by the optical mirror and the second optical mirror, it passes above or below the fourth optical mirror, and after being reflected by the third optical mirror and the fourth optical mirror, shoots to the optical wedge from below or above the third optical mirror. The two reflective surfaces of the wedge are inclined to the direction of the incident light beam; two light receiving devices are respectively used to receive the light beam reflected by the two reflective surfaces of the optical wedge; the second optical mirror is an adjustable optical mirror, which can be adjusted along the The direction of the light beam incident on the second optical mirror is reciprocatingly translated, and can rotate in the horizontal plane; the fourth optical mirror is an adjustable optical mirror, which can be reciprocally translated along the direction of the light beam exiting the fourth optical mirror, and can rotation in the vertical plane.

For the "orientation" calibration described in the present invention, it means that assuming that the transmitted light needs to pass through the diaphragms D1 and D2 and finally enter the subsequent working system, the straight line determined by the diaphragms D1 and D2 is the specific target we need to calibrate The direction of is different from the general geometric direction definition without position requirement in the prior art.

Further improved, it also includes a controller, which is used to control the movement of the second optical mirror and the fourth optical mirror respectively; the second optical mirror and the fourth optical mirror are respectively connected with a rotating motor and an electronically controlled translation platform, and the controller drives Rotate the motor and the electronically controlled translation platform to control the movement of the second reflector and the fourth reflector.

Further improved, the controller is connected with two light receiving devices, the light receiving devices are used to monitor the offset information of the spot center of the light beam reflected by the two reflective surfaces of the optical wedge and transmit it to the controller, and the controller automatically Adjust the second optical mirror and the fourth optical mirror to calibrate the exit orientation of the light beam.

As a further improvement, the first, second, third, and fourth optical mirrors are reflective mirrors, and other similar optical mirror devices that can change the direction of optical propagation are also available.

As a further improvement, the first and third optical mirrors are fixed.

As a further improvement, the direction of the light beam emitted from the calibration system is parallel to the direction of the light beam incident on the calibration system.

As a further improvement, the light receiving device is a light blocking screen, an area array photodetector, a four-quadrant detector or a display with an optical signal receiving end.

As a further improvement, the light receiving device is a light blocking screen, an area array photodetector or a display with an optical signal receiving end, such as a CMOS camera. The light receiving device has a receiving area divided into four quadrants of an orthogonal coordinate system, and the origin of the coordinate system is the central coordinate position. Different light receiving devices can be used for different calibration occasions.

As a further improvement, the second optical mirror and the third optical mirror are located on the same operating plane, and the height of the fourth optical mirror is lower than that of the second and third optical mirrors.

As a further improvement, the translation platform is a high-precision electronically controlled translation platform; the rotating motor is a high-precision stepping motor.

A further improvement also includes a host computer, such as a PC computer, etc., which is connected to the controller for visual communication control, interface operation, or auxiliary facula image denoising and offset calculation.

The second technical solution adopted to realize the object of the present invention is: a beam orientation calibration method, comprising a first optical mirror, a second optical mirror, a third optical mirror, a fourth optical mirror, an optical wedge, a light receiving device and controller, the method includes the following steps:

A. First, manually adjust the second optical mirror and the fourth optical mirror so that the light beam accurately passes through the two apertures. At this time, the central position of the light spot of the reflected light of the optical wedge detected by the light receiving device is the initial central position of the light spot;

B. After the light beam is reflected by the first optical mirror and the second optical mirror, it passes above or below the fourth optical mirror, and after being reflected by the third optical mirror and the fourth optical mirror, it passes below or above the third optical mirror The light beams reflected by the two reflective surfaces of the light wedge are received by the light receiving device;

C. The light receiving device detects the offset information of the spot center of the received light beam in real time, and transmits the offset information to the controller;

D. The controller controls the second optical mirror and the fourth optical mirror to translate or rotate according to the offset information, so as to change the offset position of the spot center of the light beam reflected by the two reflective surfaces of the optical wedge;

There are two light receiving devices, which are respectively used to detect the offset information of the spot center of the light beam reflected by the two reflecting surfaces of the optical wedge, and the distances between the two light receiving devices and the reflection point of the optical wedge are different.

As a further improvement, control the rotation of the second optical mirror and the fourth optical mirror, so that the offset information detected by the two light receiving devices tends to be the same, and reduce the offset of the center of the light spot; control the second optical mirror to do Translating can change the offset position of the center of the light spot in the horizontal direction; controlling the fourth optical mirror to perform translation can change the offset position of the center of the light spot in the vertical direction.

As a further improvement, the light receiving device is an area array photodetector, and the controller calculates the offset of the center of the light spot according to the light intensity distribution information of the light spot detected by the light receiving device, and automatically controls the first The second optical mirror and the fourth optical mirror are used to calibrate the outgoing orientation of the light beam.

As a further improvement, the calculation method of the offset size includes one or both of the following two calculation methods:

Calculation method 1. Fast positioning algorithm:

Among them, Δx and Δy are the offsets of the center of the light spot on the X and Y coordinates, and S _Ⅰ , S _Ⅱ , S _Ⅲ , and S _Ⅳ are respectively the center of the light spot falling on the four areas divided by the photosensitive surface of the detector. The area on the quadrant can be obtained by summing the intensity values of the four quadrants respectively; k is a constant coefficient;

Calculation method two, precise positioning algorithm:

in, That is, the calculated center coordinate value of the spot, I( _xi , y _i ) is the light intensity obtained by the i-th pixel on the photosensitive surface of the detector, and x _i and y _i are the coordinate values of the i-th pixel;

When the fast positioning algorithm and the precise positioning algorithm are included together, the two calculation methods can be freely switched and used.

As a further improvement, before the precise positioning algorithm calculates the offset, it first performs denoising processing on the light spot image information detected by the light receiving device.

The third technical solution adopted to achieve the purpose of the present invention is: a calibration method for the above-mentioned calibration system, comprising the following steps:

a. The two light receiving devices respectively monitor the spot offset information of the light beams reflected by the two reflective surfaces of the optical wedge in real time. The spot offset information is calculated from the center coordinates of the spot and the initial center coordinates. Using the spot offset information and the two The optical path difference of the light receiving device calculates the angular offset of the beam in the horizontal and vertical directions in real time;

b. controlling the rotation of the second optical mirror and/or the fourth optical mirror to reduce the angular offset of the light beam;

c. Repeat steps a and b to continuously reduce the angular offset to a minimum or lower than the error tolerance;

d. Using the center coordinates of the spot and the initial center coordinates, calculate the lateral offset of the beam in the horizontal direction and the vertical offset of the beam in the vertical direction in real time;

e. Adjust the translation of the second optical mirror and/or the fourth optical mirror to reduce the lateral and vertical offset of the light beam;

f. Repeating steps d and e, reducing the horizontal and vertical offsets to a minimum or lower than the error tolerance.

The beneficial effect of the present invention with respect to prior art has:

1. The present invention provides a new optical path calibration scheme. Different from other existing beam direction correction or alignment (single target) technologies, we adopt a dual-target optical path calibration based on the rotating mirror translation method.

2. Since the sensitive angular deflection is converted into an insensitive translation, under the premise of using the same device, the adjustment accuracy will be significantly improved compared with the method of only using the rotating mirror. Therefore, the calibration optical path of this system is simple, and it can achieve very high accuracy for single-target alignment applications. For azimuth offset correction (double-target) applications, the translation method can also make up for the lack of angle adjustment accuracy of ordinary rotating motors to a certain extent.

3. Introduce the optical wedge into the idea of beam calibration. For the beam orientation determined initially, the center position of the spot center of the light reflected by the two reflective surfaces of the optical wedge recorded by the two light receiving devices can uniquely reflect the orientation of the beam (two point to determine a straight line). If the azimuth of the incident beam is shifted, the centers of the light spots on the two detectors will also shift accordingly.

4. The present invention has the function of automatic real-time calibration of beam orientation, and can be used as a pre-system of various laser precision application systems. The application of this system can record the state of the normal working optical path and realize fast and accurate optical path restoration.

5. The present invention has a variety of beam calibration algorithms, namely fast positioning algorithm and precise positioning algorithm. The former is fast but not as accurate as the latter, and the latter is accurate but not as fast as the former. It can be conveniently switched and used according to the needs of different occasions.

Description of drawings

Fig. 1 is a structural connection top view diagram of an embodiment of the beam orientation calibration system of the present invention

Fig. 2 is a side view of the mutual positional relationship of the optical mirrors in the embodiment of the present invention

Fig. 3 is an example image of the light spot received by the light receiving device in the embodiment of the present invention

Fig. 4 is another example image of the light spot received by the light receiving device in the embodiment of the present invention

detailed description

The specific embodiment of the present invention will be further described below in conjunction with accompanying drawing:

Embodiment one:

A beam orientation calibration system in this embodiment includes a first optical mirror, a second optical mirror, a third optical mirror, a fourth optical mirror and an optical wedge. After the beam is reflected by the first optical mirror and the second optical mirror, Pass above or below the fourth optical mirror, and after being reflected by the third optical mirror and the fourth optical mirror, shoot from below or above the third optical mirror to the optical wedge, and the two reflective surfaces of the optical wedge are inclined to the direction of the incident light beam ; including two light receiving devices, respectively used to receive the light beams reflected by the two reflective surfaces of the optical wedge; the second optical mirror is an adjustable optical mirror, which can be configured along one side of the light beam incident on the second optical mirror reciprocating translation, and can rotate in the horizontal plane; the fourth optical mirror is an adjustable optical mirror, which can do reciprocating translation along one side of the light beam exiting the fourth optical mirror, and can rotate in the vertical plane. The first, second, third and fourth optical mirrors are reflecting mirrors, and the first and third optical mirrors are fixed. The light receiving device is the receiving end of the display, and the display displays the received light spots on the screen, which is divided into four quadrants of an orthogonal coordinate system, and the origin of the coordinate system is the central coordinate position.

This embodiment is a simple application scheme. Manually adjust the translation or rotation of the second and fourth optical mirrors by observing the deviation of the light spot on the screen to restore the center coordinate position of the light spot on the screen to achieve calibration. role. This embodiment belongs to primary application, and can be used in subsequent improved embodiment schemes.

Embodiment two:

As shown in Figure 1 and Figure 2, a kind of beam azimuth calibration system of the present embodiment, described optical mirror adopts reflector, comprises first reflector M1, second reflector M2, third reflector M3, fourth reflector The mirror M4 uses an optical wedge W as a light splitting element, and the two light receiving devices use two CMOS detectors C1 and C2 to respectively receive light beams reflected by the two reflective surfaces of the optical wedge. An attenuation sheet F is selectively placed in the reflected optical path of the optical wedge W to control the light intensity entering the detectors C1 and C2 and avoid receiving saturation.

The first reflector M1 and the third reflector M3 are fixed reflectors, the second reflector M2 and the fourth reflector M4 are adjustable reflectors, wherein the second reflector M2 can rotate in the XY plane and can be rotated along the Y direction For translation, the fourth mirror M4 can rotate on the XZ plane and can translate along the X direction. In the figure, D1 and D2 are positioning apertures. A controller 10 and a computer 20 are also included.

Laser (Laser) enters the system, after being reflected by the first reflector M1, the second reflector M2, the third reflector M3, and the fourth reflector M4, it is incident on the optical wedge W, and most of the light energy is transmitted through the optical wedge W , a small part of the light energy is reflected by the two reflective surfaces of the optical wedge W and is reflected by two CMOS detectors C1 and C2 at different positions.

The transmitted light passes through the diaphragms D1 and D2 and finally enters the subsequent working system. The straight line determined by the diaphragms D1 and D2 is the specific target direction that we need to correct, which is different from the general geometric direction definition without position requirements. It is called here It is beam azimuth calibration.

Before the system works for the first time, manually adjust the second mirror M2 and the fourth mirror M4 to make the light beam pass through the two apertures accurately. At this time, the center position of the beam spot of the wedge reflected light recorded by the CMOS detectors C1 and C2 is the initial spot The center position, at this time, uniquely reflects the positions of the diaphragms D1 and D2 (the two points determine a straight line). If the azimuth of the incident beam is shifted, the centers of the light spots on the two detectors will also shift accordingly.

When the system is working, the real-time measured light intensity distribution information on the CMOS detectors C1 and C2 is input to the controller 10 developed based on the single-chip microcomputer, and the controller 10 controls the second reflector M2 and the fourth reflector M2 and the fourth reflector M2 in real time through real-time feedback information on the center offset of the light spot. The deflection or translation of the mirror M4 enables the outgoing beam to be automatically calibrated and restored to its original orientation in real time.

In Fig. 1, when the light beam passes through the apertures D1 and D2 accurately, the central positions of the light spots recorded by the detectors C1 and C2 reflect the beam azimuth determined by D1 and D2 (double targets). When the beam is offset, the offset information obtained above can be used to control the adjustable mirror to adjust the beam orientation. When the center of the spot on C1 and C2 returns to the original recorded position, the beam will return to D1 and D2 to determine the original location.

Different from other beam direction correction or alignment (single target) technologies that have been published or reported, this embodiment adopts a dual-target calibration optical path based on the rotating mirror translation method. In Fig. 1, the second reflector M2 and the fourth reflector M4 are all driven by stepper motors and electric control translation stages respectively (in other embodiments, more expensive devices such as piezoelectric ceramic oscillating mirrors and nano-translation stages can be used , higher adjustment accuracy can be obtained, but the cost is relatively high), in which the second mirror M2 can be controlled to deflect horizontally in the XY plane, and can be translated along the beam direction (Y direction); the fourth mirror M4 can be controlled in The XZ plane deflects vertically and can translate along the beam direction (X direction).

On the XY plane ( FIG. 1 ), the light beam is reflected at about 90 degrees by the second mirror M2, and the fourth mirror M4 is slightly lower than the second mirror M2 and the third mirror M3, as shown in FIG. 2 .

The translation of the second mirror M2 can cause the light beam to generate parallel displacement in the horizontal direction. On the other hand, on the XY plane ( FIG. 1 ), the light beam returns to the fourth mirror M4 basically along the original path, so the translation of the fourth mirror M4 will only cause a vertical parallel displacement of the light beam.

While the translation of the second mirror M2 is correcting the horizontal translation of the light beam, the translation of the fourth mirror M4 can adjust the translation of the vertical direction, and the translation of the horizontal and vertical directions can be independently calibrated , so the angle and parallel offset in the horizontal and vertical directions can be accurately corrected based on the above calibration process.

Embodiment three:

The third embodiment is a method for calibrating the beam orientation, and the second embodiment can be combined with the third embodiment to become a more preferred implementation.

The beam orientation calibration method of the third embodiment includes a first optical mirror, a second optical mirror, a third optical mirror, a fourth optical mirror, an optical wedge, a light receiving device and a controller, and the method includes the following steps:

A. First, manually adjust the second optical mirror and the fourth optical mirror so that the light beam accurately passes through the two apertures. At this time, the central position of the light spot of the reflected light of the optical wedge detected by the light receiving device is the initial central position of the light spot;

B. After the light beam is reflected by the first optical mirror and the second optical mirror, it passes above or below the fourth optical mirror, and after being reflected by the third optical mirror and the fourth optical mirror, it passes below or above the third optical mirror The light beams reflected by the two reflective surfaces of the light wedge are received by the light receiving device;

C. The light receiving device detects the offset information of the spot center of the received light beam in real time, and transmits the offset information to the controller;

D. The controller controls the second optical mirror and the fourth optical mirror to translate or rotate according to the offset information, so as to change the offset position of the spot center of the light beam reflected by the two reflective surfaces of the optical wedge;

For the scheme described in the above steps, the light receiving device has two, which are respectively used to detect the offset information of the spot center of the light beam reflected by the two reflective surfaces of the optical wedge, and the distance between the two light receiving devices and the reflection point of the optical wedge is different. .

Control the second optical mirror and the fourth optical mirror to rotate, so that the offset information detected by the two light receiving devices tends to be the same, and reduce the offset of the spot center; control the second optical mirror to translate, which can change The shift position of the center of the light spot in the horizontal direction; the shift position of the center of the light spot in the vertical direction can be changed by controlling the translation of the fourth optical mirror. Repeatedly control the translation of the second optical mirror and the translation of the fourth optical mirror to reduce the offset of the center of the light spot.

The light receiving device is an area array photodetector, and the controller calculates the offset of the spot center according to the light intensity distribution information detected by the light receiving device, and automatically controls the second optical mirror and the second optical mirror according to the offset. The fourth optical mirror is used to calibrate the outgoing orientation of the light beam.

To achieve real-time azimuth calibration of the beam (laser beam), it must first be positioned. Referring to the principle of the optical path shown in Figure 1, it can be seen that the positioning of the laser beam is actually to determine the center coordinates of the light spots on the two detectors. We use CMOS as the detector, which can obtain absolute position information and comprehensive lateral distribution information of light intensity.

In addition, considering different application requirements, two different positioning algorithms are used in the system, and the two sets of algorithms can be switched freely during use.

(1) The first set of algorithms is a fast positioning algorithm, which is operated by a controller based on a single-chip microcomputer, and is used in occasions where the accuracy is not high but the real-time speed is high. Here, the CMOS image plane is regarded as the image plane of a four-quadrant detector for calculation and processing.

As shown in Figure 3, the CMOS pixel array is divided into four quadrants, and the light spots falling on it are also divided into four parts, and their areas are respectively marked as S _Ⅰ , S _Ⅱ , S _Ⅲ , and S _Ⅳ . The size of the four parts of the light spot area reflects the information of the offset of the center of the light spot relative to the center of the photosensitive surface (the origin of the four quadrants). The pixel gray values of the four quadrants are summed separately, and the obtained values are respectively proportional to the areas of the four spots, and the spot center offsets Δx and Δy can be expressed as the following calculation formulas:

In the formula, k is a constant coefficient (for a certain light source, the coefficient is determined, and the calibration coefficient k is required for different light sources). This algorithm has a fast calculation speed, and the method of taking points at intervals can further improve the processing speed.

(2) The second set of algorithms is an accurate positioning algorithm, which is used in occasions that require high precision but low real-time speed. Preferably, the calculation is performed by a host computer (computer 20 shown in FIG. 1 ), and the host computer communicates with the controller. The calculation formula is:

in, That is, the calculated center coordinates of the spot, I( _xi , y _i ) is the light intensity obtained by the i-th pixel on the photosensitive surface of the detector, and x _i and y _i are the coordinates of the i-th pixel.

The first-order moment calculation method of the above formula (2) is suitable for single-mode and multi-mode distributions. This method can make full use of the light intensity distribution information obtained by the CMOS sensor, and can obtain accurate center coordinate information of the light spot for any situation where the light spot falls on the photosensitive surface. For the situation shown in Figure 4, the first positioning method cannot obtain the center coordinates of the spot, but this method is not limited, which is one of the advantages of this method.

The optimal scheme of the second set of algorithms is that noise usually exists in the actual spot intensity distribution image detected by the detector, which has a certain influence on the spot analysis. Therefore, before the positioning calculation, the spatial domain sparse constraint algorithm can be used for denoising processing. Specifically, the sparse principal component analysis is performed on the spot image first to obtain the wavelet filter bank, which is used to transform the image into the wavelet domain and perform thresholding processing, and finally the inverse wavelet transform is performed. For different light sources, it is only necessary to perform a sparse principal component analysis at the beginning of changing the light source. The quality of the spot image after denoising will be significantly improved, but the original features of the spot will not be changed. Subsequently, the first-order moment shown in formula (2) is used to calculate the center coordinate offset of the spot.

Embodiment four:

The fourth embodiment is a calibration method applied to the above embodiments, and the fourth embodiment can be combined with the previous embodiment two or three to form a better implementation solution.

In this embodiment, a method for calibrating beam orientation includes the following steps:

a. The two light receiving devices respectively monitor the spot offset information of the light beams reflected by the two reflective surfaces of the optical wedge in real time. The spot offset information is calculated from the center coordinates of the spot and the initial center coordinates. Using the spot offset information and the two The optical path difference of the light receiving device calculates the angular offset of the beam in the horizontal and vertical directions in real time;

b. controlling the rotation of the second optical mirror and/or the fourth optical mirror to reduce the angular offset of the light beam;

c. Repeat steps a and b to continuously reduce the angular offset to a minimum or lower than the error tolerance;

d. Using the center coordinates of the spot and the initial center coordinates, calculate the lateral offset of the beam in the horizontal direction and the vertical offset of the beam in the vertical direction in real time;

e. Adjust the translation of the second optical mirror and/or the fourth optical mirror to reduce the lateral and vertical offset of the light beam;

f. Repeating steps d and e, reducing the horizontal and vertical offsets to a minimum or lower than the error tolerance.

For applications that only require single-target alignment, the precise alignment can be achieved by performing the above steps d-f cyclically. And because the sensitive angular deflection is converted into an insensitive translation, under the premise of using the same device, the adjustment accuracy will be significantly improved compared with the method of only using the rotating mirror. The calibration optical path of this system is simple, and it can achieve very high accuracy for single-target alignment applications. For azimuth offset correction (double-target) applications, the translation method can also make up for the angle adjustment accuracy of ordinary stepping motors to a large extent. lack of.

According to the disclosure and teaching of the above-mentioned specification, those skilled in the art to which the present invention belongs can also make changes and modifications to the above-mentioned embodiment. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present invention.

Claims (10)

1. A beam orientation calibration system, comprising:

the optical wedge comprises a first optical mirror, a second optical mirror, a third optical mirror, a fourth optical mirror and an optical wedge, wherein light beams pass through the upper part or the lower part of the fourth optical mirror after being reflected by the first optical mirror and the second optical mirror in sequence, and are reflected by the third optical mirror and the fourth optical mirror to be emitted to the optical wedge from the lower part or the upper part of the third optical mirror, and two reflecting surfaces of the optical wedge are inclined to the direction of incident light beams;

the optical wedge comprises two light receiving devices which are respectively used for receiving light beams reflected by two reflecting surfaces of the optical wedge;

the second optical lens is an adjustable optical lens, can perform reciprocating translation along the direction of a light beam incident on the second optical lens and can rotate in a horizontal plane;

the fourth optical lens is an adjustable optical lens, can perform reciprocating translation along the direction of a light beam which exits the fourth optical lens, and can rotate in a vertical plane.

2. The calibration system of claim 1, wherein: the controller is used for respectively controlling the movement of the second optical lens and the fourth optical lens; the second optical mirror and the fourth optical mirror are respectively connected with a rotating motor and an electric control translation table, and the controller controls the second reflecting mirror and the fourth reflecting mirror to move by driving the rotating motor and the electric control translation table.

3. The calibration system of claim 2, wherein: the controller is connected with the two light receiving devices, the light receiving devices are used for monitoring the light spot center offset information of the light beams reflected by the two reflecting surfaces of the optical wedge and transmitting the light spot center offset information to the controller, and the controller automatically adjusts the second optical lens and the fourth optical lens according to the light spot center offset information so as to calibrate the emergent direction of the light beams.

4. The calibration system of claim 1, wherein: the light receiving device is a light blocking screen, an area array photoelectric detector, a four-quadrant detector or a display with a light signal receiving end.

5. A method for beam azimuth alignment, comprising a first optic, a second optic, a third optic, a fourth optic, an optical wedge, a light receiving device, and a controller, the method comprising the steps of:

A. firstly, manually adjusting a second optical lens and a fourth optical lens to enable light beams to accurately pass through two diaphragms, wherein the light spot central position of light reflected by an optical wedge detected by a light receiving device is an initial light spot central position;

B. the light beams are reflected by the first optical mirror and the second optical mirror in sequence, pass through the upper part or the lower part of the fourth optical mirror, are reflected by the third optical mirror and the fourth optical mirror, and then are emitted to the optical wedge from the lower part or the upper part of the third optical mirror, and the light beams reflected by the two reflecting surfaces of the optical wedge are received by the light receiving device;

C. the light receiving device detects the offset information of the light spot center of the received light beam in real time and transmits the offset information to the controller;

D. the controller controls the second optical mirror and the fourth optical mirror to translate or rotate according to the offset information so as to change the light spot center offset positions of light beams reflected by the two reflecting surfaces of the optical wedge;

the two light receiving devices are respectively used for detecting the deviation information of the light spot centers of the light beams reflected by the two reflecting surfaces of the optical wedge, and the distances between the two light receiving devices and the reflecting point of the optical wedge are different.

6. The calibration method according to claim 5, wherein: controlling the second optical lens and the fourth optical lens to rotate, so that the offset information detected by the two light receiving devices tends to be the same, and reducing the offset of the center of the light spot;

the second optical lens is controlled to translate, so that the offset position of the center of the light spot in the horizontal direction can be changed; and controlling the fourth optical lens to translate, so that the offset position of the center of the light spot in the vertical direction can be changed.

7. The calibration method according to claim 6, wherein: the light receiving device is an area array photoelectric detector, the controller calculates the offset of the center of the light spot according to the light intensity distribution information of the light spot detected by the light receiving device, and automatically controls the second optical lens and the fourth optical lens according to the offset so as to calibrate the emergent direction of the light beam.

8. The calibration method according to claim 7, wherein: the calculation method of the offset magnitude comprises one or all of the following two calculation methods:

the first calculation method and the fast positioning algorithm are as follows:

$\mathrm{\Δ}x=k\frac{S_I+S_{IV}-S_{II}-S_{III}}{S_I+S_{II}+S_{III}+S_{IV}},\mathrm{\Δ}y=k\frac{S_I+S_{II}-S_{III}-S_{IV}}{S_I+S_{II}+S_{III}+S_{IV}}$

wherein, Δ X and Δ Y are the offset of the light spot center on X and Y coordinates; s_Ⅰ、S_Ⅱ、S_Ⅲ、S_ⅣThe areas of the centers of the light spots falling on four quadrants divided by a photosensitive surface of the detector are respectively, and k is a constant coefficient;

a second calculation method and an accurate positioning algorithm:

$\stackrel{\‾}{x}=\frac{\underset{i}{\Σ}I(x_i,y_i)x_i}{\underset{i}{\Σ}I(x_i,y_i)},\stackrel{\‾}{y}=\frac{\underset{i}{\Σ}I(x_i,y_i)y_i}{\underset{i}{\Σ}I(x_i,y_i)}$

wherein,i.e. the calculated central coordinate value of the light spot, I (x)_i,y_i) The intensity, x, obtained for the ith pixel element on the photosensitive surface of the detector_i、y_iCoordinate value of ith pixel element;

when the fast positioning algorithm and the accurate positioning algorithm are jointly included, the two calculation methods can be freely switched to use.

9. The calibration method according to claim 8, wherein: and denoising the light spot image information detected by the light receiving device before calculating the offset by using the accurate positioning algorithm.

10. A calibration method for use with the calibration system of claim 3, comprising the steps of:

a. the two light receiving devices respectively monitor the light spot deviation information of light beams reflected by the two reflecting surfaces of the optical wedge in real time, the light spot deviation information is obtained by calculating the center coordinates of the light spots and the initial center coordinates, and the angle deviation amounts of the light beams in the horizontal direction and the vertical direction are calculated in real time by using the light spot deviation information and the optical path difference of the two light receiving devices;

b. controlling the second optical mirror and/or the fourth optical mirror to rotate, and reducing the angle offset of the light beam;

c. the steps a and b are circulated, so that the angle offset is continuously reduced to the minimum or is lower than the error tolerance;

d. calculating the transverse offset of the light beam in the horizontal direction and the vertical offset of the light beam in the vertical direction in real time by using the central coordinate of the light spot and the initial central coordinate;

e. adjusting the second optical lens and/or the fourth optical lens to translate, and reducing the transverse and vertical offset of the light beam;

f. and d, repeating the steps d and e, and reducing the transverse offset and the vertical offset to the minimum or lower than the error tolerance.