Automatic focusing method and system for laser far-field measurement

Abstract

The present invention discloses an automatic focusing method and system for laser far-field measurement, which generates a first data sequence by moving a detector from a first preset position to a second preset position; determines an intermediate position between the first preset position and the second preset position based on the first data sequence; moves the detector from the second preset position to a third preset position, and generates a second data sequence when the detector passes through the intermediate position during the movement; and determines a suitable focal length of the detector based on the first data sequence and the second data sequence, thereby realizing automatic focusing of laser far-field measurement. In this process, it is only necessary to control the movement of the detector and calculate the focusing evaluation function, without having to stop the detector multiple times to obtain far-field imaging. The technical solution has a simple process, is stable and easy to implement. Compared with the prior art, it reduces the complexity of the focusing device and realizes fast, stable and effective automatic focusing.

Description

Technical Field

[0001] The present 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 typically refers to measuring the characteristics of a laser beam's spot in an area far from the source (the far field), including parameters such as the spot's size, shape, and intensity distribution. This measurement is widely used for analyzing the effects of high-intensity laser light propagation in the atmosphere and evaluating the performance of laser systems.

[0003] In laser far-field measurement, the focal length of the detector needs to be adjusted for accurate measurement. 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 the challenges of 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] Determining, based on the first data sequence, a midpoint 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 and adjust the focus.

[0012] Furthermore, 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] Acquiring a first moving position according to a process in which the detector moves from the first preset position to the second preset position;

[0016] For any first moving position, determining a focusing evaluation function corresponding to the first moving position according to the 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 movement positions and the focus evaluation functions respectively corresponding to the plurality of first movement positions.

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

[0019] determining a first intermediate position according to the focus evaluation functions 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, where 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 based on 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 based on the first distance and the second distance; and the second intermediate position is determined based on the third distance and the first intermediate position.

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

[0025] The detector moves from the second preset position to the third preset position while maintaining the preset speed and 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] Acquiring a second moving position according to a process in which the detector moves from the second preset position to the intermediate position;

[0028] For any second moving position, determining a focusing evaluation function corresponding to the second moving position according to the 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] Furthermore, 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 focusing 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 quadratic fit based on the first optimal position and the preset distance to determine a first fitting optimal position;

[0036] Performing a quadratic fit based on 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 images;

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

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

[0047] Determining 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, a focusing evaluation function corresponding to the target position, and a 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 is used to execute an automatic focusing method for laser far-field measurement.

[0057] Compared with the prior art, the present 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 an evaluation index of focusing, and the focusing evaluation indexes of different moving positions can be used to evaluate whether the focal lengths of different moving positions are reasonable; furthermore, the data sequence can be used to determine a suitable focal length of the detector and realize 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, without the need to stop the detector multiple times to obtain far-field imaging. Therefore, the process of this technical solution is simple, stable and easy to implement. Compared with the existing technology, it reduces the complexity of the focusing device and realizes 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 examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. 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 1 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 examples and drawings. The exemplary embodiments of the present invention and their descriptions 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 a method for laser beam diagnostics. It uses far-field imaging of a laser beam to calculate relevant parameters. The most common application is the measurement of the laser beam quality factor (β factor), which is defined as the ratio of the actual measured beam's surrounding radius to the ideal beam's surrounding radius.

[0069] In actual measurement, it is necessary to ignore the defocus aberration of the laser beam while performing the measurement. Therefore, a focusing mechanism is required to compensate for the far-field distortion caused by the defocus aberration of the laser beam. Generally, due to the large equivalent focal length of far-field measurement, the focusing range is also relatively large. Usually, a motorized translation stage is used to drive the far-field measurement detection device, such as a CCD (charge-coupled device) or CMOS (complementary metal oxide semiconductor), to adjust to the appropriate range.

[0070] Motorized translation stages typically operate in modes such as with linear scales or closed-loop stepper motors. For synchronized scanning and measurement, the stage moves to a designated position and stops before calculating the relevant parameters of the laser far field. Because focusing is a global search process, this can be very slow, affecting the efficiency of measuring the relevant parameters of the laser far field. However, if the stage is not allowed to move to the designated position, the stage will be in motion during the imaging process, and the acquisition of the stage's position will be affected by the delay of the stage's data interface, resulting in inconsistencies between the stage's position and the measured parameters.

[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 move the detector from one end of the translation stage to the other end at a uniform speed, and the position of the translation stage is read back in real time and the focusing evaluation index is calculated. After moving into position, the relative optimal value position is found, and the translation stage is moved at a uniform speed 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 a working mode with a grating ruler or a closed-loop stepping motor.

[0074] Accordingly, 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 can be a controller, a processor, a control device (e.g., a host computer), a processing device, etc., which are not limited herein. The control device can not only control the driving device so that the driving device drives the translation stage to move, but also obtain the translation stage's movement position information and calculate evaluation indicators. Furthermore, 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. This position 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 shows a flow chart 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] In step S21, a translation stage carrying a detector is controlled to move from a first preset position to a second preset position, and a first data sequence is generated during the movement of the translation stage, wherein the first data sequence includes a plurality of first movement positions and focus 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] In step S23, the translation stage carrying the detector is controlled to move from the second preset position to the third preset position, passing through the intermediate position, and generating 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 may 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 may be first controlled to move from the current position to the first preset position, and then 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 based on the starting and ending positions of the translation stage, and the drive device can move the translation stage according to the drive control instructions. Therefore, corresponding drive control can be achieved based on the first preset position, the second preset position, the current position, or any other position of the translation stage.

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

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

[0087] In some embodiments, there are corresponding limits for the moving positions 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 plurality of first movement 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 the first data sequence accordingly.

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

[0091] In some embodiments, the focus evaluation function may be the aforementioned β factor, i.e., 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 this field and will not be introduced in detail here.

[0093] It is understood that in the embodiment of the present disclosure, the beam quality factor is used as the focus evaluation function. However, this focus evaluation function is the result of measurement during the movement of the translation stage. Therefore, this 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 embodiment, the beam quality factor corresponding to the laser beam is not directly used as the final focusing evaluation function, but influencing factors need to be considered.

[0096] In some embodiments, the beam quality factor of the laser beam at different movement speeds can be pre-measured. Based on the measured results, the effect of movement speed on the beam quality factor of the laser beam can be analyzed to determine the corresponding relationship between movement speed and the beam quality factor. Furthermore, based on the preset movement speed and the pre-measured corresponding relationship between movement speed and beam quality factor, the current beam quality factor can be determined.

[0097] The beam quality impact factor may be an impact 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 the focusing evaluation function corresponding to the first moving position based on the beam quality factor and the 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 beam quality factor for each moving position, it is necessary to multiply the measured beam quality factor by the beam quality influence factor to obtain the final focus evaluation function. Thus, the first data sequence can be generated using the focus evaluation functions corresponding to the multiple first moving positions and 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 translation stage, Indicates 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 indicates a better beam quality, 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 can 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 can contain more data when the translation stage moves for the second time, so as to achieve more accurate focusing.

[0104] Therefore, as an optional embodiment, step S22 includes: determining a first intermediate position according to the focusing evaluation functions corresponding to the 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 the position closer to the first preset position among the multiple first intermediate positions; if there is one first intermediate position, 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 based on the first distance and the second distance.

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

[0106] In some embodiments, determining a second intermediate position based on the first distance and the 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; and 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 indicates that the first intermediate position is likely closer to the first preset position, ensuring that the second data sequence covers more locations. Therefore, the first intermediate position can be directly determined as the final intermediate position, i.e., the second intermediate position. If the first distance is greater than or equal to the second distance, it indicates that the first intermediate position is closer to the second preset position, which does not ensure that the second data sequence covers more locations. Therefore, a third distance can be determined based on the first and second distances, and then the final intermediate position, i.e., the second intermediate position, can be determined based on the third distance and the first intermediate position.

[0108] The third distance can be the difference between the first distance and the second distance. If the third distance is 0, i.e., the first distance and the second distance are equal, then the second intermediate position can be obtained by adding half of the first distance or the second distance toward the first preset position to the first intermediate position. If the third distance is not 0, then the second intermediate position can be obtained by adding the third distance toward the first preset position to the first intermediate position.

[0109] Furthermore, in step S23, the translation stage is controlled to move from the second preset position to the third preset position and pass through the intermediate position. It can be understood that the intermediate 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 intermediate 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, specifically including: maintaining a preset speed when moving the translation stage equipped with a detector from the second preset position to the third preset position through the intermediate position; determining the beam quality factor and the beam quality influence factor corresponding to the laser beam according to the preset speed; obtaining the 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 the 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; generating the second data sequence according to multiple second movement positions and the focusing evaluation functions corresponding to the multiple second movement positions respectively.

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

[0112] In combination with the aforementioned 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 this generation process, the specific implementation method can refer to the generation method of the aforementioned first data sequence, and 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, ensuring that it passes through x0. During this process, the stage position is read back in real time and the focus evaluation function f(x) is calculated to obtain the position-evaluation function sequence (i.e., the second data sequence) of M positions sampled. Where i=1,2,…,M, represents the position of the translation stage, Indicates 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 movement 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 embodiment, step S24 includes: determining a first optimal position among multiple first moving positions based on focusing evaluation functions corresponding to multiple first moving positions; determining a second optimal position among the second moving positions based on focusing evaluation functions corresponding to multiple second moving positions; determining a target position based on 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 embodiment, a first optimal position can be determined from the plurality of first movement positions, and the focus evaluation function corresponding to the first optimal position is the optimal focus evaluation function, for example, the minimum value of the beam quality factor. Similarly, a second optimal position can be determined from the plurality of second movement positions, and the focus evaluation function corresponding to the second optimal position is the optimal focus evaluation function, for example, the minimum value of the 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. 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 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, quadratic fitting is performed on the first optimal position and the preset distance range respectively to determine the first fitting optimal position and the 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, the aforementioned preset distance range may be changed accordingly depending on the quadratic fitting algorithm.

[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 the preset distance, the target position is determined based on the first optimal position and the second optimal position, including: controlling the translation stage to move from the 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 obtaining 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 obtaining a second far-field imaging of the laser beam; fitting the first optimal position and the second optimal position based on 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, performing data fitting may result in poor accuracy of the final target position. 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, it is only required for specific acquisition and will not affect the focusing efficiency.

[0129] 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 a first far-field image of the laser beam is acquired at this position. Then, the translation stage is again controlled to move from the 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 a second far-field image of the laser beam is acquired at this position.

[0131] Furthermore, fitting the first optimal position and the second optimal position based on the first far-field image and the second far-field image may include: determining the far-field distortion corresponding to the first far-field image and the second far-field image; if the far-field distortion corresponding to the first far-field image and the second far-field image are the same, performing a quadratic fit based on a position intermediate between the first optimal position and the second optimal position to determine the target position. If the far-field distortion corresponding to the first far-field image and the second far-field image are different, performing a quadratic fit based on a position corresponding to the far-field image 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 in FIG, the change of the β factor with the position of the translation stage is shown, wherein, if there is no corresponding β factor value, it is considered that the focusing evaluation function is 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 in FIG, the change of the β factor with the position of the translation stage is shown, wherein, if there is no corresponding β factor value, it is considered that the focusing evaluation function is invalid.

[0136] based on Figure 4 The second data sequence shown, combined with Figure 3 For the first data sequence shown, a quadratic fit was performed near the corresponding optimal solution positions (±10 mm). The optimal positions x1 = -2.315 mm and x2 = -2.935 mm were calculated, respectively. Using the aforementioned formula, the final target position is xopt = (x1 + x2) / 2 = -2.615 mm. The stage is moved to this position to complete the focusing.

[0137] When this embodiment is adopted, the parameters of the detector can also be adjusted accordingly. Therefore, as an optional embodiment, the method further includes: acquiring a third far-field image of the laser beam at the target position; performing image transformation based on the first far-field image to obtain multiple first transformed far-field images; performing image transformation based on the second far-field image to obtain multiple second transformed far-field images; determining the measurement parameters of the detector based on the first far-field image, the second far-field image, the third far-field image, the first transformed far-field image, the second transformed far-field image, 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 based on the measurement parameters of the detector.

[0138] It is 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 by collecting far-field images at the corresponding three positions.

[0139] However, the far-field images collected at three locations have insufficient data to fully analyze image distortion caused by detector parameters. Therefore, image transformation can be performed on the first and second far-field images to obtain more far-field images. This image transformation can refer to established techniques 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] Therefore, the focusing evaluation functions 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 results output by the pre-trained prediction model, and the measurement parameters of the detector can be adjusted according to the prediction results.

[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 a human for manual processing. Alternatively, it can be based on established rules and conditions, for example: a pre-set adjustment rule is set, and the parameter adjustment can be performed 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 be referred to the mature technology in this field and will not be described 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, and 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 imaging, 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 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, multiple sample far-field imaging and multiple transformed sample far-field imaging are used to train the encoder, the encoder is also used to output multiple encoded far-field imaging, and the multiple encoded far-field imaging, focusing evaluation function labels and detector measurement parameter labels are used to train the decoder.

[0147] In this embodiment, the prediction model adopts an image transformation layer + encoder + decoder structure. Among them, the image transformation layer is mainly used for model training and has little effect in subsequent model applications.

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

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

[0150] Furthermore, the image transformation layer outputs multiple transformed sample far-field images based on the input image transformation layer. These multiple transformed sample far-field images and the multiple sample far-field images can be input into an encoder for training, so that the trained encoder can encode far-field images or transformed far-field images. Furthermore, based on the multiple encoded far-field images, the focus evaluation function labels, and the detector measurement parameter labels, they can be input into a decoder for training, so that the trained decoder can predict the measurement parameters.

[0151] In some embodiments, if the encoder is an unsupervised encoder, the encoder may not include a feature extraction component. If the encoder is a supervised encoder, it may also include a feature extraction component. The features extracted by this feature extraction component are used as training labels for the encoder to train the encoder. In other words, the encoded far-field image output by the encoder can be understood as image features.

[0152] Through this model training method, the generalization ability of the model can be guaranteed, making the prediction model more accurate.

[0153] As can be seen from the description of the disclosed embodiments, the disclosed embodiments do not rely on the stage's multiple stops for capturing images, significantly improving focusing efficiency. Furthermore, the optimal position is determined through data fitting, resulting in a simple algorithm and low hardware cost, further improving focusing efficiency.

[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 is understood that the electronic device may serve 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. For example, these data may include instructions for any application or method used to operate on the electronic device, as well as application-related data, such as contact data, sent and received messages, 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 (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk or optical disk. The multimedia components 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 above-mentioned 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 one possible embodiment, the electronic device may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the above-mentioned automatic focusing method for laser far-field measurement.

[0157] In one possible embodiment, a computer-readable storage medium including program instructions is further provided. When executed by a processor, the program instructions implement the steps of the aforementioned automatic focusing method for laser far-field measurement. For example, the computer-readable storage medium may be the aforementioned memory including the program instructions. The program instructions may be executed by a processor of an electronic device to implement the aforementioned automatic focusing method for laser far-field measurement.

[0158] In a possible embodiment, a computer program product is further 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 further 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 of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection 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 appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0162] In addition, the 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: The detector is moved from a first preset position to a second preset position to generate a first data sequence, wherein the generating of the first data sequence includes: the detector maintains a preset speed when moving from the first preset position to the second preset position; according to the preset speed, a beam quality factor and a beam quality influence factor corresponding to the laser beam are determined; according to the process of the detector moving from the first preset position to the second preset position, a first moving position is obtained; for any first moving position, a focusing evaluation function corresponding to the first moving position is determined according to the beam quality factor and the beam quality influence factor of the laser beam at the first moving position ; Generate the first data sequence according to the plurality of first moving positions and the focusing evaluation functions corresponding to the plurality of first moving positions respectively ,in, , represents the position of the translation stage, Indicates that the control device obtains the position of the translation stage as Focus evaluation function when ; Determining, based on a first data sequence, an intermediate position between a first preset position and a second preset position, comprising: determining, based on focus evaluation functions corresponding to a plurality of first moving positions, a first intermediate position being an optimal position among the plurality of first moving positions; if there are a plurality of first intermediate positions, determining a second intermediate position from the plurality of first intermediate positions, the second intermediate position being a position closest to the first preset position among the plurality of first intermediate positions; if there is only one first intermediate position, obtaining a distance between the first intermediate position and the first preset position as a first distance, and obtaining a distance between the first intermediate position and the second preset position as a second distance; determining a second intermediate position based on the first distance and the second distance; 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; and determining the second intermediate position based on the third distance and the first intermediate position; The detector is moved from the second preset position to the third preset position, and the detector passes through an intermediate position during the movement, and a second data sequence is generated, wherein the generating the second data sequence includes: The detector moves from the second preset position to the third preset position while maintaining the preset speed and 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; Acquiring a second moving position according to a process in which the detector moves from the second preset position to the intermediate position; For any second moving position, determining a focusing evaluation function corresponding to the second moving position according to the 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 corresponding to the plurality of second moving positions. ,in , represents the position of the translation stage, Indicates that the control device obtains the position of the translation stage as Focus evaluation function when ; Determining a target position based on a first data sequence and a second data sequence includes: determining a first optimal position among a plurality of first moving positions based on focus evaluation functions corresponding to the plurality of first moving positions; determining a second optimal position among a plurality of second moving positions based on focus evaluation functions corresponding to the plurality of second moving positions; and determining a target position based on the first optimal position and the second optimal position. , Indicates the target location, represents the first optimal position, represents the second best position; In the process of determining the target location: If the distance between the first optimal position and the second optimal position is greater than the preset distance, then: Performing a quadratic fit based on the first optimal position and the preset distance to determine a first fitting optimal position; Performing a quadratic fit based on the second optimal position and the preset distance to determine a second fitting optimal position; determining a target position according to the first optimal fitting position and the second optimal fitting 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; 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; Move the detector to the target position and adjust the focus.

2. The automatic focusing method for laser far-field measurement according to claim 1, characterized in that: Automatic focus adjustment 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 images; Performing image transformation according to the second far-field imaging to obtain a plurality of second transformed far-field images; Constructing a prediction model, pre-training the prediction model, and obtaining a pre-trained prediction model; Determining 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, a focusing evaluation function corresponding to the target position, and a pre-trained prediction model; According to the measurement parameters of the detector, the detector is controlled to perform laser far-field measurement.

3. The automatic focusing method for laser far-field measurement according to claim 2, 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.

4. 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 according to any one of claims 1 to 3.

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