Automatic focusing method and system for laser far-field measurement

Abstract

The invention discloses an automatic focusing method and system for laser far-field measurement, and the method comprises the steps: moving a detector from a first preset position to a second preset position, and generating a first data sequence; determining a middle position between the first preset position and the second preset position according to the first data sequence; moving the detector from the second preset position to a third preset position, enabling the detector to pass through the middle position during moving, and generating a second data sequence; according to the first data sequence and the second data sequence, the appropriate focal length of the detector can be determined through the data sequences, automatic focusing of laser far-field measurement is achieved, in the process, only the detector needs to be controlled to move, a focusing evaluation function is calculated, the detector does not need to be stopped for multiple times to obtain far-field imaging, and the automatic focusing of laser far-field measurement is achieved. According to the technical scheme, the process is simple, stable and easy to implement, compared with the prior art, the complexity of the focusing device is reduced, and rapid, stable and effective automatic focusing is achieved.

Description

Technical Field

[0001] The invention relates to the field of laser technology, and in particular to an automatic focusing method and system for laser far-field measurement. Background Art

[0002] Laser far-field measurement usually refers to the measurement of the spot characteristics of the laser beam in an area far away from the emission source (far-field area), which includes parameters such as the size, shape and intensity distribution of the spot. This measurement is widely used in analyzing the transmission effect of strong lasers in the atmosphere and evaluating the performance of laser systems.

[0003] In laser far-field measurement, in order to perform accurate measurement, the focal length of the detector needs to be adjusted. The laser autofocus system involves complex optical and electronic technologies, which requires operators to have certain professional knowledge and skills, increasing the difficulty of use and maintenance. At the same time, additional control equipment or measures are required to ensure the accuracy and reliability of the measurement. Traditional far-field measurement methods, such as CCD imaging or detector dot matrix methods, may be limited by the dynamic range of the detector and are difficult to meet the requirements of high-precision measurement. The accuracy of laser far-field measurement may be affected by factors such as the number of detectors, array layout, and installation accuracy, all of which may introduce additional errors. In summary, the automatic focusing method of laser far-field measurement needs to overcome challenges in technical complexity, environmental requirements, and measurement accuracy in practical applications. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the existing focusing methods are complex, have high adjustment requirements and low precision. The purpose is to provide an automatic focusing method and system for laser far-field measurement, which reduces the complexity of the focusing device and thus achieves fast, stable and effective automatic focusing.

[0005] The present invention is achieved through the following technical solutions:

[0006] A first aspect of the present invention provides an automatic focusing method for laser far-field measurement, comprising the following specific steps:

[0007] Moving the detector from a first preset position to a second preset position to generate a first data sequence;

[0008] Determine, according to the first data sequence, a middle position between the first preset position and the second preset position;

[0009] moving the detector from the second preset position to the third preset position, the detector passing through an intermediate position during the movement, and generating a second data sequence;

[0010] Determining a target location based on the first data sequence and the second data sequence;

[0011] Move the detector to the target position for focusing.

[0012] Further, generating the first data sequence includes:

[0013] The detector moves at a preset speed when moving from the first preset position to the second preset position;

[0014] Determining a beam quality factor and a beam quality influencing factor corresponding to the laser beam according to the preset speed;

[0015] Acquire a first moving position according to a process in which the detector moves from a first preset position to a second preset position;

[0016] For any first moving position, determining a focusing evaluation function corresponding to the first moving position according to a beam quality factor of the laser beam at the first moving position and the beam quality influence factor;

[0017] The first data sequence is generated according to the plurality of first moving positions and the focus evaluation functions respectively corresponding to the plurality of first moving positions.

[0018] Further, determining the middle position between the first preset position and the second preset position according to the first data sequence includes:

[0019] Determine a first intermediate position according to the focus evaluation functions respectively corresponding to the plurality of first moving positions, wherein the first intermediate position is an optimal position among the plurality of first moving positions;

[0020] If there are multiple first intermediate positions, a second intermediate position is determined from the multiple first intermediate positions, and the second intermediate position is the position closest to the first preset position among the multiple first intermediate positions;

[0021] If the number of the first intermediate positions is one, the distance between the first intermediate position and the first preset position is obtained as the first distance, and the distance between the first intermediate position and the second preset position is obtained as the second distance; the second intermediate position is determined according to the first distance and the second distance:

[0022] If the first distance is smaller than the second distance, determining the first intermediate position as the second intermediate position;

[0023] If the first distance is greater than or equal to the second distance, a third distance is determined according to the first distance and the second distance; and the second intermediate position is determined according to the third distance and the first intermediate position.

[0024] Further, generating the second data sequence includes:

[0025] The detector moves from the second preset position to the third preset position while maintaining a preset speed passing through the intermediate position;

[0026] Determining a beam quality factor and a beam quality influencing factor corresponding to the laser beam according to the preset speed;

[0027] According to the process of the detector moving from the second preset position to the intermediate position, obtaining a second moving position;

[0028] For any second moving position, determining a focusing evaluation function corresponding to the second moving position according to a beam quality factor of the laser beam at the second moving position and the beam quality influence factor;

[0029] The second data sequence is generated according to the plurality of second moving positions and the focus evaluation functions respectively corresponding to the plurality of second moving positions.

[0030] Further, determining the target position according to the first data sequence and the second data sequence includes:

[0031] Determining a first optimal position among the plurality of first moving positions according to the focusing evaluation functions respectively corresponding to the plurality of first moving positions;

[0032] determining a second optimal position among the second moving positions according to the focus evaluation functions respectively corresponding to the plurality of second moving positions;

[0033] A target position is determined according to the first optimal position and the second optimal position.

[0034] Furthermore, when determining the target position, if the distance between the first optimal position and the second optimal position is greater than a preset distance, then:

[0035] Performing a secondary fit according to the first optimal position and the preset distance to determine a first fitting optimal position;

[0036] Performing a secondary fit according to the second optimal position and the preset distance to determine a second fitting optimal position;

[0037] A target position is determined according to the first optimal fitting position and the second optimal fitting position.

[0038] Furthermore, when determining the target position, if the distance between the first optimal position and the second optimal position is less than a preset distance, then:

[0039] Controlling the translation stage to move from the third preset position to a position closer to the third preset position between the first optimal position and the second optimal position, and acquiring a first far-field imaging of the laser beam;

[0040] Controlling the translation stage to move from a position closer to the third preset position between the first optimal position and the second optimal position to a position farther from the third preset position between the first optimal position and the second optimal position, and acquiring a second far-field imaging of the laser beam;

[0041] The first optimal position and the second optimal position are fitted according to the first far-field imaging and the second far-field imaging to determine the target position.

[0042] Furthermore, automatically focusing the detector further includes:

[0043] acquiring a third far-field image of the detector laser beam at the target location;

[0044] Performing image transformation according to the first far-field imaging to obtain a plurality of first transformed far-field imaging;

[0045] Performing image transformation according to the second far-field imaging to obtain a plurality of second transformed far-field imaging;

[0046] Constructing a prediction model, pre-training the prediction model, and obtaining a pre-trained prediction model;

[0047] Determine the measurement parameters of the detector according to the first far-field imaging, the second far-field imaging, the third far-field imaging, the first transformed far-field imaging, the second transformed far-field imaging, the focusing evaluation function corresponding to the target position and the pre-trained prediction model;

[0048] According to the measurement parameters of the detector, the detector is controlled to perform laser far-field measurement.

[0049] Furthermore, the pre-training of the prediction model to obtain the pre-trained prediction model includes:

[0050] Acquire a training data set, wherein the training data set includes a plurality of training samples, each training sample includes: a plurality of sample far-field images, a focus evaluation function label, and a detector measurement parameter label;

[0051] According to the training data set, the prediction model to be trained is trained to obtain the pre-trained prediction model; wherein the prediction model to be trained includes: an image transformation layer, an encoder and a decoder, some sample far-field imaging of the multiple sample far-field imaging are used to input the image transformation layer, the image transformation layer is used to output multiple transformed sample far-field imaging, the multiple sample far-field imaging and the multiple transformed sample far-field imaging are used to train the encoder, the encoder is also used to output multiple encoded far-field imaging, the multiple encoded far-field imaging, the focusing evaluation function label and the detector measurement parameter label are used to train the decoder.

[0052] A second aspect of the present invention provides an automatic focusing system for laser far-field measurement, comprising:

[0053] Translation stage;

[0054] a detector mounted on the translation stage;

[0055] a driving device connected to the translation stage;

[0056] A control device is connected to the translation stage, the detector and the driving device respectively, and the control device is used to execute an automatic focusing method for laser far-field measurement.

[0057] Compared with the prior art, the invention has the following advantages and beneficial effects:

[0058] By controlling the movement of the detector and obtaining a corresponding data sequence, the corresponding data sequence includes focusing evaluation functions corresponding to different moving positions; the focusing evaluation function can be equivalent to a focusing evaluation index, and using the focusing evaluation indexes of different moving positions, it can be evaluated whether the focal lengths of different moving positions are reasonable; further, using the data sequence, the appropriate detector focal length can be determined to achieve automatic focusing of laser far-field measurement; in this technical solution, it is only necessary to control the movement of the detector and calculate the focusing evaluation function, and there is no need to stop the detector multiple times to obtain far-field imaging. Therefore, the technical solution has a simple, stable and easy-to-implement process. Compared with the prior art, it reduces the complexity of the focusing device and achieves fast, stable and effective automatic focusing. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0060] Figure 1 Schematic diagram of the structure of the laser far-field measurement system in an embodiment of the present invention;

[0061] Figure 2 is a flow chart of an automatic focusing method for laser far-field measurement in an embodiment of the present invention;

[0062] Figure 3 is a schematic diagram of a first data sequence curve in an embodiment of the present invention;

[0063] Figure 4 is a schematic diagram of a second data sequence curve in an embodiment of the present invention;

[0064] Figure 5 FIG. 4 is a connection diagram of electronic devices in an embodiment of the present invention. DETAILED DESCRIPTION

[0065] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0066] The technical solution provided in this embodiment can be applied to various scenarios involving laser far-field measurement, and is specifically used to adjust the focal length of laser far-field measurement.

[0067] Laser beam diagnostics has a wide range of applications in laser systems, especially in high-energy laser systems.

[0068] Laser far-field measurement is one of the methods for laser beam diagnosis. It calculates the relevant parameters of the laser far-field by imaging the far-field of the laser beam. Among them, the most widely used is the measurement of the laser beam quality factor (β factor), which is defined as the ratio of the actual measurement beam's circumference radius to the ideal beam's circumference radius.

[0069] In the actual measurement process, it is necessary to measure under the condition of ignoring the defocus aberration of the laser beam, so a focusing mechanism is needed to compensate for the far-field distortion caused by the defocus aberration of the laser beam. In general, since the equivalent focal length of far-field measurement is relatively large, the focusing range is also relatively large. Usually, an electric translation stage is used to drive the detection device of far-field measurement, such as CCD (Charge-coupled Device) or CMOS (Complementary Metal Oxide Semiconductor), to adjust to the appropriate range.

[0070] Electric translation stages generally have working modes such as grating rulers or closed-loop stepper motors. If synchronous scanning-measurement work is performed, that is, the translation stage moves to the specified position and stops, then the relevant parameters of the laser far field are calculated. Since focusing is a global search process, the focusing speed will be very slow, which will affect the measurement efficiency of the relevant parameters of the laser far field. However, if the translation stage is not moved to the specified position, the translation stage is moving during the imaging process, and the position acquisition of the translation stage will be affected by the delay of the translation stage data interface, which will lead to inconsistency between the translation stage position and parameter measurement.

[0071] As an optional implementation, the first aspect of this embodiment provides an automatic focusing method for laser far-field measurement. In this technical solution, when performing laser far-field focusing, an electric translation stage is used to uniformly move the detector from one end of the translation stage to the other end, and the position of the translation stage is read back in real time and the focusing evaluation index is calculated. After moving into place, the relative optimal value position is found, and the translation stage is uniformly moved through the optimal value position. During this process, the position of the translation stage is read back in real time and the focusing evaluation index is calculated. The optimal focusing position can be obtained by the relationship between the translation stage position and the evaluation index obtained twice, and the translation stage is moved to this position to achieve automatic focusing. The method has a simple process, is stable and easy to implement. Compared with the existing methods, it reduces the complexity of the focusing device, thereby achieving fast, stable and effective automatic focusing.

[0072] As an optional implementation, Figure 1 As shown, the system includes: a translation stage; a detector mounted on the translation stage; a driving device connected to the translation stage; and a control device connected to the translation stage, the detector and the driving device respectively.

[0073] In some possible embodiments, the translation stage may be the aforementioned electric translation stage, which generally has working modes such as a grating ruler or a closed-loop stepping motor.

[0074] Correspondingly, the driving device may be a closed-loop stepping motor to control the movement of the electric translation stage.

[0075] In some embodiments, the detector may be the aforementioned CCD or CMOS, etc., which can measure the laser beam.

[0076] It can be understood that the system may also include a laser, which is used to emit a laser beam, and the emission direction of the laser beam is toward the detector.

[0077] In some embodiments, the control device may be a controller, a processor, a control device (such as a host computer), and a processing device, etc., which are not limited here. Regarding the control device, it can not only control the driving device so that the driving device drives the translation stage to move; it can also obtain the moving position information of the translation stage and calculate the evaluation index. In addition, after determining a reasonable translation stage position, the driving device is controlled so that the driving device determines that the translation stage moves to a reasonable translation stage position, which is the detector position after focusing. At this position, the detector can better measure the laser beam accordingly.

[0078] As an optional implementation, Figure 2 FIG. 1 is a flowchart of an automatic focusing method for laser far-field measurement, which can be applied to Figure 1The control device in the automatic focusing method comprises the following steps:

[0079] Step S21, controlling the translation stage carrying the detector to move from the first preset position to the second preset position, and generating a first data sequence during the movement of the translation stage, wherein the first data sequence includes a plurality of first movement positions and focusing evaluation functions corresponding to the plurality of first movement positions.

[0080] Step S22: determining an intermediate position between the first preset position and the second preset position according to the first data sequence.

[0081] Step S23, control the translation stage to carry the detector and move from the second preset position to the third preset position, and pass through the intermediate position, and generate a second data sequence during the translation stage movement. The second data sequence includes a plurality of second movement positions and focus evaluation functions corresponding to the plurality of second movement positions.

[0082] Step S24, determining the target position according to the first data sequence and the second data sequence, and focusing the detector.

[0083] In step S21, if the initial position of the translation stage is the first preset position, the translation stage can be directly controlled to move from the first preset position to the second preset position. If the initial position of the translation stage is not the first preset position, in step S21, the translation stage can be first controlled to move from the current position to the first preset position, and then the translation stage can be controlled to move from the first preset position to the second preset position.

[0084] In some embodiments, the control device can generate corresponding drive control instructions to the drive device according to the starting position and the end position of the translation stage, and the drive device moves the translation stage according to the drive control instructions. Therefore, the corresponding drive control can be realized based on the first preset position, the second preset position, the current position or any displacement position of the translation stage.

[0085] In addition, when generating the driving control instruction, the moving speed of the translation stage may also be limited, thereby making the moving speed of the translation stage controllable.

[0086] It can be understood that the driving control of the translation stage can refer to the relevant technology of realizing the driving control of the translation stage based on the driving motor in the mature laser far-field measurement technology in the art, and will not be introduced in detail here.

[0087] In some embodiments, there are corresponding limits for the moving position of the translation stage. For example, if the limits of the translation stage include limit 1 and limit 2, then the first preset position may be limit 1, the second preset position may be limit 2, and the distance between limit 1 and limit 2 is the total distance that the translation stage can move.

[0088] During the movement of the translation stage, the control device synchronously generates a first data sequence, which includes: a plurality of first movement positions and focus evaluation functions corresponding to the plurality of first movement positions.

[0089] The multiple first moving positions can be understood as positions between the first preset position and the second preset position. When the translation stage moves, the translation stage is equipped with a corresponding position monitoring device, which can transmit the real-time position of the translation stage back to the control device, and the control device can generate a first data sequence accordingly.

[0090] The focus evaluation function can be used to evaluate whether the focal length of the corresponding movement position is appropriate.

[0091] In some embodiments, the focus evaluation function may be the aforementioned β factor, that is, the quality of the laser beam. Therefore, during the movement of the translation stage, the laser may emit a laser beam, and the focus evaluation function may be obtained based on the laser beam detected by the detector.

[0092] Regarding the measurement method of the β factor, reference may be made to the mature technology in the field and will not be introduced in detail here.

[0093] It can be understood that in the embodiment of the present disclosure, the beam quality factor is used as the focus evaluation function, but the focus evaluation function is the result measured during the movement of the translation stage. Therefore, the focus evaluation function may be affected accordingly.

[0094] Therefore, as an optional implementation, the moving speed of the translation stage is maintained at a preset moving speed, and the method further includes: determining a beam quality influencing factor corresponding to the laser beam according to the preset moving speed.

[0095] In this implementation, the beam quality factor corresponding to the laser beam is not directly used as the final focusing evaluation function, but the influencing factors need to be considered.

[0096] In some embodiments, the beam quality factor corresponding to the laser beam at different moving speeds can be measured in advance, and then, based on the measured results, the influence of the moving speed on the beam quality factor corresponding to the laser beam is analyzed, thereby determining the corresponding relationship between the moving speed and the beam quality influence factor. Furthermore, based on the preset moving speed and the corresponding relationship between the moving speed and the beam quality influence factor obtained by the pre-measurement, the current beam quality influence factor can be determined.

[0097] The beam quality influencing factor may be an influencing weight, and its value may be between 0 and 1.

[0098] Correspondingly, generating the first data sequence may include: for any first moving position, determining a focusing evaluation function corresponding to the first moving position based on a beam quality factor and a beam quality influence factor of the laser beam at the first moving position; generating the first data sequence based on multiple first moving positions and the focusing evaluation functions corresponding to the multiple first moving positions respectively.

[0099] In this embodiment, when measuring the light speed quality factor of each moving position, it is necessary to multiply the measured beam quality factor by the beam quality influence factor to obtain the final focusing evaluation function. Thus, the first data sequence can be generated from the multiple first moving positions and the focusing evaluation functions corresponding to the multiple first moving positions.

[0100] For example, assuming that the focus evaluation function is f(x), the position evaluation function sequence (i.e., the first data sequence) of N positions is obtained by sampling: Where i = 1, 2, ..., N, represents the position of the stage, It means that the control device obtains the position of the translation stage as Focus evaluation function when .

[0101] In step S22, an intermediate position between the first preset position and the second preset position is determined according to the first data sequence.

[0102] In some embodiments, the focus evaluation function corresponding to the middle position is the optimal focus evaluation function. For example, if a smaller beam quality factor represents a better beam quality, then the position with the smallest beam quality factor is determined as the middle position.

[0103] In other embodiments, the first preset position and the second preset position may be combined to determine other intermediate positions. The focusing evaluation function corresponding to the other intermediate positions may not be optimal, but the acquired data sequence may contain more data when the translation stage moves for the second time, so as to achieve more accurate focusing.

[0104] Therefore, as an optional implementation, step S22 includes: determining a first intermediate position according to focusing evaluation functions corresponding to multiple first moving positions, the first intermediate position being the optimal position among the multiple first moving positions; if there are multiple first intermediate positions, determining a second intermediate position from the multiple first intermediate positions, the second intermediate position being a position closer to the first preset position among the multiple first intermediate positions; if there are one first intermediate positions, determining a first distance between the first intermediate position and the first preset position, and determining a second distance between the first intermediate position and the second preset position; determining the second intermediate position according to the first distance and the second distance.

[0105] In this embodiment, the optimal position of the focus evaluation function can be determined first as the first intermediate position. Considering that there may be more than one optimal focus evaluation function, it is possible to first determine whether there are multiple first intermediate positions. If there are multiple first intermediate positions, a position closer to the first preset position is further determined from the multiple first intermediate positions as the second intermediate position, and the second intermediate position is the final intermediate position. If there is only one, the first distance between the first intermediate position and the first preset position can be determined, and the second distance between the first intermediate position and the second preset position can be determined; the second intermediate position is determined based on the first distance and the second distance.

[0106] In some embodiments, determining a second intermediate position based on a first distance and a second distance includes: if the first distance is less than the second distance, determining the first intermediate position as the second intermediate position; if the first distance is greater than or equal to the second distance, determining a third distance based on the first distance and the second distance; determining the second intermediate position based on the third distance and the first intermediate position.

[0107] In this embodiment, if the first distance is less than the second distance, it means that the first intermediate position may be closer to the first preset position, which can ensure that the second data sequence covers more positions, and the first intermediate position can be directly determined as the final intermediate position, that is, the second intermediate position. If the first distance is greater than or equal to the second distance, it means that the first intermediate position is closer to the second preset position, and it cannot ensure that the second data sequence covers more positions. Therefore, the third distance can be determined based on the first distance and the second distance, and then the final intermediate position, that is, the second intermediate position, can be determined based on the third distance and the first intermediate position.

[0108] The third distance may be the difference between the first distance and the second distance. If the third distance is 0, that is, the first distance and the second distance are equal, then the second intermediate position may be obtained by adding the first distance or half of the second distance in the direction of the first preset position based on the first intermediate position. If the third distance is not 0, then the second intermediate position may be obtained by adding the third distance in the direction of the first preset position based on the first intermediate position.

[0109] Further, in step S23, the translation stage is controlled to move from the second preset position to the third preset position and pass through the middle position. It can be understood that the middle position is between the second preset position and the third preset position, and the third preset position is between the first preset position and the middle position.

[0110] Thus, during the movement of the translation stage, a second data sequence can be generated with reference to the generation method of the above-mentioned first data sequence, which specifically includes: maintaining a preset speed while moving the translation stage equipped with a detector from a second preset position to a third preset position through an intermediate position; determining a beam quality factor and a beam quality influence factor corresponding to the laser beam according to the preset speed; obtaining a second movement position according to the process of the detector moving from the second preset position to the intermediate position; for any second movement position, determining a focusing evaluation function corresponding to the second movement position according to the beam quality factor and the beam quality influence factor of the laser beam at the second movement position; and generating a second data sequence according to a plurality of second movement positions and the focusing evaluation functions respectively corresponding to the plurality of second movement positions.

[0111] Therefore, the generated second data sequence includes: a plurality of second moving positions and focus evaluation functions respectively corresponding to the plurality of second moving positions.

[0112] In combination with the foregoing embodiments, the generation of the second data sequence may include: for any second moving position, determining the focusing evaluation function corresponding to the second moving position based on the beam quality factor and the beam quality influence factor of the laser beam at the second moving position; and generating the second data sequence based on multiple second moving positions and the focusing evaluation functions corresponding to the multiple second moving positions respectively.

[0113] In the generation process, the specific implementation method can refer to the generation method of the first data sequence mentioned above, which will not be repeated here.

[0114] For example, assuming the middle position is based on the sequence If the position x0 is determined, the stage is moved to the specified position x1 in the direction of limit 1 to ensure that it passes through x0. In this process, the stage position is read back in real time and the focusing evaluation function f(x) is calculated to obtain the position-evaluation function sequence (i.e., the second data sequence) of the M positions obtained by sampling. Where i = 1, 2, ..., M, represents the position of the stage, It means that the control device obtains the position of the translation stage as Focus evaluation function when .

[0115] In some embodiments, if the corresponding focus evaluation function is not obtained for some moving positions, the corresponding focus evaluation function is marked as invalid.

[0116] In step S24, the detector is adjusted using the first data sequence and the second data sequence.

[0117] As an optional implementation, step S24 includes: determining a first optimal position among multiple first moving positions according to focusing evaluation functions corresponding to multiple first moving positions respectively; determining a second optimal position among second moving positions according to focusing evaluation functions corresponding to multiple second moving positions respectively; determining a target position according to the first optimal position and the second optimal position; and controlling the translation stage to move from a third preset moving position to the target position to complete the focusing of the detector.

[0118] In this implementation, a first optimal position can be determined from a plurality of first moving positions, and the focus evaluation function corresponding to the first optimal position is an optimal focus evaluation function, such as a minimum value of a beam quality factor. Similarly, a second optimal position can be determined from a plurality of second moving positions, and the focus evaluation function corresponding to the second optimal position is an optimal focus evaluation function, such as a minimum value of a beam quality factor.

[0119] It can be understood that the first optimal position and the second optimal position are different positions.

[0120] Furthermore, based on the first optimal position and the second optimal position, the target position can be determined, and the target position is regarded as the detector position with the most reasonable and appropriate focal length. Therefore, the focusing of the detector can be completed by moving the translation stage from the third preset moving position to the target position.

[0121] As a first optional implementation, when the distance between the first optimal position and the second optimal position is greater than a preset distance, the target position is determined based on the first optimal position and the second optimal position, including: performing quadratic fitting based on the first optimal position and the preset distance range to determine the first fitting optimal position; performing quadratic fitting based on the second optimal position and the preset distance range to determine the second fitting optimal position; and determining the target position based on the first fitting optimal position and the second fitting optimal position.

[0122] The preset distance may be half of the distance between the first preset position and the second preset position, for example, the preset distance may be 10 mm. Accordingly, the preset distance range is ±10 mm.

[0123] In some embodiments, a second fitting is performed on the first optimal position and the preset distance range respectively to determine a first fitting optimal position and a second fitting optimal position, thereby determining the target position using the first fitting optimal position and the second fitting optimal position.

[0124] The quadratic fitting algorithm may adopt various mature fitting algorithms in the art. Accordingly, according to different quadratic fitting algorithms, the aforementioned preset distance range may be changed accordingly.

[0125] Furthermore, the target position may be an intermediate position between the first optimal fitting position and the second optimal fitting position. opt =(x 1 +x 2 ) / 2,x opt represents the target position, x 1 represents the first fitting optimal position, x 2 represents the second best fit position.

[0126] As an optional embodiment, when the distance between the first optimal position and the second optimal position is less than a preset distance, determining the target position according to the first optimal position and the second optimal position, including: controlling the translation stage to move from a third preset position to a position of the first optimal position and the second optimal position that is closer to the third preset position, and acquiring a first far-field imaging of the laser beam; controlling the translation stage to move from a position of the first optimal position and the second optimal position that is closer to the third preset position to a position of the first optimal position and the second optimal position that is farther from the third preset position, and acquiring a second far-field imaging of the laser beam; fitting the first optimal position and the second optimal position according to the first far-field imaging and the second far-field imaging to determine the target position.

[0127] In this embodiment, since the distance between the first optimal position and the second optimal position is less than the preset distance, if data fitting is performed, the final target position may be less accurate. Therefore, in this case, far-field imaging can be further combined to achieve more accurate judgment.

[0128] Furthermore, in this embodiment, although far-field imaging is required, far-field imaging is only required for specific acquisition, which will not affect the focusing efficiency.

[0129] Among them, regarding the implementation of far-field imaging, reference may be made to mature technologies in the art.

[0130] Therefore, the translation stage is first controlled to move from the third preset position to a position closer to the third preset position between the first optimal position and the second optimal position, and the first far-field imaging of the laser beam is acquired at this position. Then, the translation stage is controlled to move from a position closer to the third preset position between the first optimal position and the second optimal position to a position farther from the third preset position between the first optimal position and the second optimal position, and the second far-field imaging of the laser beam is acquired at this position.

[0131] Further, fitting the first optimal position and the second optimal position based on the first far-field imaging and the second far-field imaging may include: determining the far-field distortions corresponding to the first far-field imaging and the second far-field imaging respectively; if the far-field distortions corresponding to the first far-field imaging and the second far-field imaging respectively are the same, then performing a secondary fitting based on the middle position between the first optimal position and the second optimal position to determine the target position. If the far-field distortions corresponding to the first far-field imaging and the second far-field imaging respectively are different, then performing a secondary fitting based on the position corresponding to the far-field imaging with smaller far-field distortion to determine the target position.

[0132] Among them, determining the far-field distortion corresponding to the first far-field imaging and the second far-field imaging, respectively, may include: analyzing and comparing the first far-field imaging and the second far-field imaging with preset far-field imaging without far-field distortion (for example, analyzing image similarity), and determining the far-field distortion of the first far-field imaging and the second far-field imaging, respectively.

[0133] like Figure 3 As shown, it shows the change of the β factor with the position of the translation stage, wherein there is no corresponding β factor value, which means that the focusing evaluation function is considered invalid.

[0134] based on Figure 3 The first data sequence shown can determine the middle position: x0 = -1.6519 mm.

[0135] like Figure 4 As shown, it shows the change of the β factor with the position of the translation stage, wherein there is no corresponding β factor value, which means that the focusing evaluation function is considered invalid.

[0136] based on Figure 4 The second data sequence shown, combined with Figure 3 The first data sequence shown is quadratically fitted near the corresponding optimal solution positions (±10 mm), and the optimal positions x1 = -2.315 mm and x2 = -2.935 mm are calculated respectively. The target position is finally obtained by calculating through the above calculation formula: xopt = (x1 + x2) / 2 = -2.615 mm. Move the translation stage to this position to complete the focusing.

[0137] In the case of adopting this embodiment, the parameters of the detector can also be adjusted accordingly. Therefore, as an optional embodiment, the method also includes: acquiring a third far-field imaging of the laser beam at the target position; performing image transformation according to the first far-field imaging to obtain multiple first transformed far-field imaging; performing image transformation according to the second far-field imaging to obtain multiple second transformed far-field imaging; determining the measurement parameters of the detector according to the first far-field imaging, the second far-field imaging, the third far-field imaging, the first transformed far-field imaging, the second transformed far-field imaging, the focusing evaluation function corresponding to the target position and the pre-trained prediction model; and controlling the detector to perform laser far-field measurement according to the measurement parameters of the detector.

[0138] It can be understood that far-field imaging can not only reflect far-field distortion, but also image distortion that may be caused by detector parameters. Therefore, the detector parameters can be adjusted through far-field imaging collected at the corresponding three positions.

[0139] However, since the far-field imaging collected at three positions has too little data, it is not possible to fully analyze the image distortion caused by the detector parameters. Therefore, the first far-field imaging and the second far-field imaging can be transformed to obtain more far-field imaging. The image transformation method can refer to mature technologies in the field, such as geometric transformation, perspective transformation, and distance transformation.

[0140] In addition, the first far-field imaging and the second far-field imaging may also include far-field distortion, so the far-field distortion can be eliminated by combining the focus evaluation function corresponding to the target position.

[0141] Thus, the focusing evaluation function corresponding to the first far-field imaging, the second far-field imaging, the third far-field imaging, the first transformed far-field imaging, the second transformed far-field imaging and the target position can be input into the pre-trained prediction model to obtain the prediction result output by the pre-trained prediction model, and the measurement parameters of the detector can be adjusted according to the prediction result.

[0142] For example, the prediction results of the pre-trained prediction model can be used to indicate whether the measurement parameters of the detector need to be adjusted, or to indicate specific measurement parameter adjustment items, etc. Thus, the corresponding measurement parameters can be adjusted according to the prediction results.

[0143] Regarding the specific adjustment method of the measurement parameters, it can be adjusted manually, that is, fed back to the human and processed manually. Alternatively, it can also be based on established rule conditions, for example: an adjustment rule is pre-set, and the parameters can be adjusted according to the adjustment rule. The preset adjustment rule can be a default parameter adjustment method under the influence of the quality of far-field imaging. Among them, the influence of different parameters on the quality of far-field imaging can refer to the mature technology in this field, which will not be introduced in detail here.

[0144] The measurement parameters of the detector may be adjustable parameters such as frame rate, exposure time and dynamic range, as well as parameters that affect the far-field imaging quality.

[0145] The pre-trained prediction model may be a random forest model or a large language model, which may adopt different model algorithms or different model structures, which are not limited here.

[0146] As an optional implementation, the training of the prediction model includes: obtaining a training data set, the training data set includes multiple training samples, each training sample includes: multiple sample far-field images, focusing evaluation function labels and detector measurement parameter labels; according to the training data set, the prediction model to be trained is trained to obtain a pre-trained prediction model; wherein the prediction model to be trained includes: an image transformation layer, an encoder and a decoder, some sample far-field images of the multiple sample far-field images are used to input the image transformation layer, the image transformation layer is used to output multiple transformed sample far-field images, the multiple sample far-field images and the multiple transformed sample far-field images are used to train the encoder, the encoder is also used to output multiple encoded far-field images, and the multiple encoded far-field images, focusing evaluation function labels and detector measurement parameter labels are used to train the decoder.

[0147] In this implementation, the prediction model adopts the structure of image transformation layer + encoder + decoder, wherein the image transformation layer is mainly used for model training and has little effect in subsequent model application.

[0148] It can be understood that since the training data used in model training does not include far-field imaging based on image transformation, a new image transformation layer is added to train the generalization ability of the encoder and decoder.

[0149] Regarding multiple sample far-field images, the number can be small, but they need to cover different detector positions (focal lengths). The focus evaluation function label can be the optimal beam quality factor. The detector measurement parameter label, referring to the above embodiment, can indicate whether the measurement parameters need to be adjusted, or indicate the specific measurement parameter items that need to be adjusted.

[0150] Furthermore, the image transformation layer outputs a plurality of transformed sample far-field images based on the input image transformation layer. The plurality of transformed sample far-field images and the plurality of sample far-field images can be input into the encoder together to train the encoder so that the trained encoder can encode the far-field image or the transformed far-field image. Furthermore, based on the plurality of encoded far-field images, the focus evaluation function label and the detector measurement parameter label, the decoder can be input for training so that the trained decoder can realize the prediction of the measurement parameters.

[0151] In some embodiments, if the encoder is an unsupervised encoder, the encoder may not include a feature extraction part. If the encoder is a supervised encoder, it may also include a feature extraction part, and the features extracted by the feature extraction part are used as training labels of the encoder to train the encoder. That is, the encoded far-field imaging output by the encoder can be understood as image features.

[0152] This model training method can ensure the generalization ability of the model and make the prediction model more accurate.

[0153] It can be seen from the introduction of the embodiments of the present disclosure that the embodiments of the present disclosure do not rely on the multiple stops of the translation stage to take pictures, which can greatly improve the focusing efficiency. In addition, the determination of the optimal position is achieved through data fitting, the algorithm is simple, the hardware cost is also low, and the focusing efficiency can be improved.

[0154] like Figure 5 As shown, the electronic device may include: a processor, a memory. The electronic device may also include one or more of a multimedia component, an input / output (I / O) interface, and a communication component. It can be understood that the electronic device can be used as the aforementioned control device.

[0155] The processor is used to control the overall operation of the electronic device to complete all or part of the steps in the above-mentioned automatic focusing method. The memory is used to store various types of data to support the operation of the electronic device, and these data may include, for example, instructions for any application or method used to operate on the electronic device, and application-related data, such as contact data, messages sent and received, pictures, audio, video, etc. The memory can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (Static Random Access Memory, referred to as SRAM), electrically erasable programmable read-only memory (Electrically Erasable Programmable Read-Only Memory, referred to as EEPROM), erasable programmable read-only memory (Erasable Programmable Read-Only Memory, referred to as EPROM), programmable read-only memory (Programmable Read-Only Memory, referred to as PROM), read-only memory (Read-Only Memory, referred to as ROM), magnetic memory, flash memory, disk or optical disk. The multimedia component may include a screen and an audio component. The screen may be, for example, a touch screen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signal may be further stored in a memory or sent through a communication component. The audio component also includes at least one speaker for outputting audio signals. The I / O interface provides an interface between the processor and other interface modules, and the other interface modules may be a keyboard, a mouse, buttons, etc. These buttons may be virtual buttons or physical buttons. The communication component is used for wired or wireless communication between the electronic device and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G or 4G, or a combination of one or more of them, so the corresponding communication component may include: a Wi-Fi module, a Bluetooth module, an NFC module.

[0156] In a possible embodiment, the electronic device can be implemented by one or more application specific integrated circuits (Application Specific Integrated Circuit, referred to as ASIC), digital signal processors (Digital Signal Processor, referred to as DSP), digital signal processing devices (Digital Signal Processing Device, referred to as DSPD), programmable logic devices (Programmable Logic Device, referred to as PLD), field programmable gate arrays (Field Programmable Gate Array, referred to as FPGA), controllers, microcontrollers, microprocessors or other electronic components to perform the above-mentioned automatic focusing method for laser far-field measurement.

[0157] In a possible embodiment, a computer-readable storage medium including program instructions is also provided, and when the program instructions are executed by a processor, the steps of the automatic focusing method for laser far-field measurement are implemented. For example, the computer-readable storage medium may be the above-mentioned memory including program instructions, and the above-mentioned program instructions may be executed by a processor of an electronic device to complete the above-mentioned automatic focusing method for laser far-field measurement.

[0158] In a possible embodiment, a computer program product is also provided. The computer program product includes a computer program that can be executed by a processor. When the computer program is executed by the processor, the steps of the above-mentioned automatic focusing method for laser far-field measurement are implemented.

[0159] In a possible embodiment, a computer program product is also provided. The computer program product includes a computer program that can be executed by a processor. When the computer program is executed by the processor, the steps of the above-mentioned automatic focusing method for laser far-field measurement are implemented.

[0160] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0161] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0162] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

[0163] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An automatic focusing method for laser far-field measurement, characterized in that: The specific steps include: Moving the detector from a first preset position to a second preset position to generate a first data sequence; Determine, according to the first data sequence, a middle position between the first preset position and the second preset position; moving the detector from the second preset position to the third preset position, the detector passing through an intermediate position during the movement, and generating a second data sequence; Determining a target location based on the first data sequence and the second data sequence; Move the detector to the target position for focusing.

2. The automatic focusing method for laser far-field measurement according to claim 1, characterized in that: The generating of the first data sequence comprises: The detector moves at a preset speed when moving from the first preset position to the second preset position; Determining a beam quality factor and a beam quality influencing factor corresponding to the laser beam according to the preset speed; Acquire a first moving position according to a process in which the detector moves from a first preset position to a second preset position; For any first moving position, determining a focusing evaluation function corresponding to the first moving position according to a beam quality factor of the laser beam at the first moving position and the beam quality influence factor; The first data sequence is generated according to the plurality of first moving positions and the focus evaluation functions respectively corresponding to the plurality of first moving positions.

3. The automatic focusing method for laser far-field measurement according to claim 2, characterized in that: The step of determining, according to the first data sequence, a middle position between the first preset position and the second preset position comprises: Determine a first intermediate position according to the focus evaluation functions respectively corresponding to the plurality of first moving positions, wherein the first intermediate position is an optimal position among the plurality of first moving positions; If there are multiple first intermediate positions, a second intermediate position is determined from the multiple first intermediate positions, and the second intermediate position is the position closest to the first preset position among the multiple first intermediate positions; If the number of the first intermediate positions is one, the distance between the first intermediate position and the first preset position is obtained as the first distance, and the distance between the first intermediate position and the second preset position is obtained as the second distance; the second intermediate position is determined according to the first distance and the second distance: If the first distance is smaller than the second distance, determining the first intermediate position as the second intermediate position; If the first distance is greater than or equal to the second distance, a third distance is determined according to the first distance and the second distance; and the second intermediate position is determined according to the third distance and the first intermediate position.

4. The automatic focusing method for laser far-field measurement according to claim 1, characterized in that: The generating of the second data sequence comprises: The detector moves from the second preset position to the third preset position while maintaining a preset speed passing through the intermediate position; Determining a beam quality factor and a beam quality influencing factor corresponding to the laser beam according to the preset speed; According to the process of the detector moving from the second preset position to the intermediate position, obtaining a second moving position; For any second moving position, determining a focusing evaluation function corresponding to the second moving position according to a beam quality factor of the laser beam at the second moving position and the beam quality influence factor; The second data sequence is generated according to the plurality of second moving positions and the focus evaluation functions respectively corresponding to the plurality of second moving positions.

5. The automatic focusing method for laser far-field measurement according to claim 1, characterized in that: The step of determining the target position according to the first data sequence and the second data sequence includes: Determining a first optimal position among the plurality of first moving positions according to the focusing evaluation functions respectively corresponding to the plurality of first moving positions; determining a second optimal position among the second moving positions according to the focus evaluation functions respectively corresponding to the plurality of second moving positions; A target position is determined according to the first optimal position and the second optimal position.

6. The automatic focusing method for laser far-field measurement according to claim 5, characterized in that: When determining the target position, if the distance between the first optimal position and the second optimal position is greater than the preset distance, then: Performing a secondary fit according to the first optimal position and the preset distance to determine a first fitting optimal position; Performing a secondary fit according to the second optimal position and the preset distance to determine a second fitting optimal position; A target position is determined according to the first optimal fitting position and the second optimal fitting position.

7. The automatic focusing method for laser far-field measurement according to claim 5, characterized in that: When determining the target position, if the distance between the first optimal position and the second optimal position is less than the preset distance, then: Controlling the translation stage to move from the third preset position to a position closer to the third preset position between the first optimal position and the second optimal position, and acquiring a first far-field imaging of the laser beam; Controlling the translation stage to move from a position closer to the third preset position between the first optimal position and the second optimal position to a position farther from the third preset position between the first optimal position and the second optimal position, and acquiring a second far-field imaging of the laser beam; The first optimal position and the second optimal position are fitted according to the first far-field imaging and the second far-field imaging to determine the target position.

8. The automatic focusing method for laser far-field measurement according to claim 7, characterized in that: Automatic focusing of the detector also includes: acquiring a third far-field image of the detector laser beam at the target location; Performing image transformation according to the first far-field imaging to obtain a plurality of first transformed far-field imaging; Performing image transformation according to the second far-field imaging to obtain a plurality of second transformed far-field imaging; Constructing a prediction model, pre-training the prediction model, and obtaining a pre-trained prediction model; Determine the measurement parameters of the detector according to the first far-field imaging, the second far-field imaging, the third far-field imaging, the first transformed far-field imaging, the second transformed far-field imaging, the focusing evaluation function corresponding to the target position and the pre-trained prediction model; According to the measurement parameters of the detector, the detector is controlled to perform laser far-field measurement.

9. The automatic focusing method for laser far-field measurement according to claim 8, characterized in that: The pre-training of the prediction model to obtain the pre-trained prediction model includes: Acquire a training data set, wherein the training data set includes a plurality of training samples, each training sample includes: a plurality of sample far-field images, a focus evaluation function label, and a detector measurement parameter label; According to the training data set, the prediction model to be trained is trained to obtain the pre-trained prediction model; wherein the prediction model to be trained includes: an image transformation layer, an encoder and a decoder, some sample far-field imaging of the multiple sample far-field imaging are used to input the image transformation layer, the image transformation layer is used to output multiple transformed sample far-field imaging, the multiple sample far-field imaging and the multiple transformed sample far-field imaging are used to train the encoder, the encoder is also used to output multiple encoded far-field imaging, the multiple encoded far-field imaging, the focusing evaluation function label and the detector measurement parameter label are used to train the decoder.

10. An automatic focusing system for laser far-field measurement, characterized in that: include: Translation stage; a detector mounted on the translation stage; a driving device connected to the translation stage; A control device connected to the translation stage, the detector and the driving device respectively, wherein the control device is used to execute the automatic focusing method for laser far-field measurement as described in any one of claims 1 to 9.

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