Automatic focusing sparse aperture imaging system and focusing method

Abstract

The invention relates to the technical field of sparse aperture imaging systems, in particular to an automatic focusing sparse aperture imaging system and a focusing method.On the control method level, a target image collected by the sparse aperture imaging system is processed through an image processing system, and an automatic focusing system is controlled in combination with an algorithm control system; therefore, automatic focusing is realized. In the structural level, an automatic focusing system comprising a lens cone, a focusing power mechanism, a focusing limiting mechanism and an industrial camera CCD is arranged, the focusing power mechanism comprises a servo motor, a driving wheel and other components, the focusing limiting mechanism comprises a double-thread mechanism, the driving wheel can be driven to rotate through the servo motor, and the driving wheel can be driven to rotate through the double-thread mechanism. And the driving wheel drives the nut of the double-thread mechanism to rotate to enable the industrial camera CCD to move, so that the problems that an existing sparse aperture imaging system is not provided with an automatic focusing system, the focus position is changed due to different distances between an observed object and the imaging system, and manual focusing is needed by personnel are solved.

Description

Technical Field

[0001] The invention relates to the technical field of sparse aperture imaging systems, and in particular to an automatic focusing sparse aperture imaging system and a focusing method. Background Art

[0002] A sparse aperture imaging system is a system that combines several sub-apertures of the same structure in a specific position layout relationship to replace a single large-aperture telescope. It can achieve the same spatial resolution as a large-aperture optical imaging system. Figure 1 As shown, the three-aperture imaging system array is as follows Figure 2 As shown, in both figures, d represents the sub-aperture diameter, and D represents the circumscribed circle diameter of the sub-aperture.

[0003] Since the optical sparse aperture imaging system uses several small-aperture entrance pupils instead of large-aperture entrance pupils, the intermediate frequency response of the system MTF is partially missing, and the intermediate frequency response directly affects the final imaging quality. By changing the optimal design of the sub-aperture array arrangement, the intermediate frequency part of the MTF information can be effectively compensated. Among them, the filling factor is an important performance indicator of the sparse aperture telescope system, which reflects the degree of sparseness of the sparse aperture telescope system.

[0004] The fill factor is defined as:

[0005]

[0006] The horizontal MTF curve of an ideal dual-aperture system at different filling factors is as follows: Figure 3 As shown in the figure, it can be seen that the filling factor directly affects the intermediate frequency part of the MTF.

[0007] The system fill factor can be changed by adjusting the focus, thereby changing the MTF value to improve the image quality. The relationship curve between focal length, zoom ratio and fill factor is as follows: Figure 4 shown.

[0008] Depend on Figure 4 It can be seen that the focal length of the system is inversely proportional to the fill factor and zoom ratio, that is, as the focal length decreases, the entrance pupil diameter decreases, and the fill factor and zoom ratio increase. The focal length of the focus imaging system can be continuously changed within a certain range, which is more conducive to presenting better image quality. The image quality at different focal lengths is as follows: Figure 5 shown.

[0009] Since the optical path principle of the automatic focusing sparse aperture imaging system is as follows Figure 6As shown in the figure, the incident light of the system is reflected twice by the primary mirror and the secondary mirror of the sub-aperture, and then reflected by the plane mirror to reach the entrance pupil of the beam combiner, and finally forms an image on the CCD image plane. The different distances of the observed object from the imaging system will cause the focus position to change, so the system focus needs to be adjusted in real time according to the distance of the observed object. Summary of the invention

[0010] In view of the above problems, the present invention provides an automatic focusing sparse aperture imaging system and a focusing method.

[0011] The adopted technical solution is an automatic focusing sparse aperture imaging system, comprising a sparse aperture imaging system and an automatic focusing system, wherein the automatic focusing system is arranged at the observation end of the sparse aperture imaging system, and further comprising an image processing system and an algorithm control system;

[0012] The image processing system is used to receive the target image sent by the sparse aperture imaging system, process it and transmit it to the algorithm control system;

[0013] The algorithm control system generates a control voltage to control the automatic focusing system according to the processing result of the image processing system.

[0014] Optionally, the automatic focusing system includes a lens barrel, a focusing power mechanism, a focusing limit mechanism and an industrial camera CCD;

[0015] One end of the lens barrel is connected to the observation end of the sparse aperture imaging system;

[0016] The focusing power mechanism and the focusing limit mechanism are both arranged at the other end of the lens barrel, and the focusing power mechanism can be controlled by the automatic focusing method to drive the focusing limit mechanism to move;

[0017] The industrial camera CCD is arranged at one end of the focus limiting mechanism, and the industrial camera CCD can move linearly on the focus limiting mechanism.

[0018] Optionally, the focusing power mechanism includes a motor mounting seat, a servo motor and a driving wheel, and the motor mounting seat is arranged at the other end of the lens barrel;

[0019] The servo motor is mounted on a motor mounting seat, and the servo motor is connected to the controller signal;

[0020] The driving wheel is connected to the power output end of the servo motor, and the driving wheel can drive the focus limiting mechanism to move.

[0021] Optionally, the focus limiting mechanism includes a first threaded screw, a connecting sleeve and a second threaded screw;

[0022] The first threaded screw is connected to the other end of the lens barrel and is disposed below the motor mounting seat;

[0023] One end of the connecting sleeve is connected to the first threaded screw, and the other end of the connecting sleeve is connected to the second threaded screw, and the outer periphery of the connecting sleeve can mesh with the driving wheel;

[0024] The industrial camera CCD is arranged on the second threaded screw.

[0025] Optionally, both the first threaded screw and the second threaded screw are hollow tube structures.

[0026] Optionally, the outer circumference of the first threaded screw is a reverse external thread, the outer circumference of the second threaded screw is a forward external thread, the end of the connecting sleeve facing the first threaded screw is provided with a reverse internal thread, and the end of the connecting sleeve facing the second threaded screw is provided with a forward internal thread.

[0027] Optionally, the focus limiting mechanism further includes a guide rod and a guide block;

[0028] The guide rod is connected to the other end of the lens barrel and is arranged below the first threaded screw;

[0029] The guide block is sleeved on the guide rod, and the guide block is connected to the CCD of the industrial camera.

[0030] The present invention also provides a sparse aperture imaging system automatic focusing method, comprising the following steps:

[0031] S1. Capturing an image of a target object through a sparse aperture imaging system and transmitting the captured image to an image processing system;

[0032] S2. The image processing system normalizes the image and generates a performance evaluation function J;

[0033] S3. The algorithm control system iterates the performance evaluation function J and controls the voltage of the automatic focusing system according to the iteration result;

[0034] S4. In the automatic focusing system, the servo motor adjusts the CCD position of the industrial camera according to the control voltage to achieve automatic focusing.

[0035] Optionally, in S2, the expression of the performance evaluation function J is:

[0036] ;

[0037] In the formula, is the imaging surface coordinate, is the ideal image grayscale value, is the actual image grayscale value.

[0038] Optionally, in S3, the iteration formula is:

[0039] ;

[0040] In the formula, u is the driving voltage of the autofocus system, k is the number of iterations, and u is k is the adjustment voltage during the kth adjustment, u k-1 is the regulation voltage during the k-1th regulation, To impose The performance evaluation indicators after To impose The performance evaluation indicators after represents the amplitude of random disturbances that follow Bernoulli distribution, is the first-order corrected momentum of the gradient, is the second-order corrected momentum of the gradient, c1, c2 are constant parameters, is the initial gain coefficient, is a micro-valued constant;

[0041] When performing the kth iteration, the first-order corrected momentum and second-order corrected momentum of the gradient are calculated as:

[0042] ;

[0043] ;

[0044] ;

[0045] ;

[0046] In the formula, m gk is the first-order momentum of the gradient at the kth iteration, is the first-order momentum of the gradient at the k-1th iteration, and its initial value is 0; v gk is the second-order momentum of the gradient; is the estimated value of the gradient at the kth iteration; is the square of the estimated gradient at the kth iteration; , is the momentum factor.

[0047] The beneficial effects of the present invention include at least one of the following:

[0048] 1. At the control method level, the target image collected by the sparse aperture imaging system is processed by the image processing system, and the automatic focusing system is controlled in combination with the algorithm control system to achieve automatic focusing.

[0049] 2. On the structural level, an automatic focusing system is set up including a lens barrel, a focusing power mechanism, a focusing limit mechanism and an industrial camera CCD. The focusing power mechanism includes a servo motor, a driving wheel and other components, and the focusing limit mechanism includes a double-thread mechanism. The driving wheel can be driven by the servo motor to rotate, and the driving wheel drives the nut of the double-thread mechanism to rotate to move the industrial camera CCD. At the same time, automatic focusing is achieved through an adaptive control algorithm.

[0050] 3. The existing sparse aperture imaging system has no automatic focusing system. Due to the different distances between the observed object and the imaging system, the focal position will change, requiring personnel to manually focus. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic diagram of the structure of a two-aperture imaging system;

[0052] Figure 2 This is a schematic diagram of the three-aperture imaging system structure:

[0053] Figure 3 It is the curve of MTF changing with filling factor F;

[0054] Figure 4 It is the relationship diagram between focal length f, zoom ratio M and fill factor F;

[0055] Figure 5 Schematic diagram of imaging quality at different focal lengths;

[0056] Figure 6 This is the optical path diagram of the focusing sparse aperture imaging system;

[0057] Figure 7 It is a schematic diagram of the connection between the sparse aperture imaging system and the automatic focusing system;

[0058] Figure 8 It is a structural diagram of the automatic focusing system;

[0059] Fig. 9 It is a schematic diagram of the explosion structure of the automatic focusing system;

[0060] Fig.10 It is the algorithm control process diagram;

[0061] Fig.11 is the calculation flow chart;

[0062] Fig.12 This is the imaging result before automatic focusing;

[0063] Fig.13 It is a curve diagram of the number of iterations and the corresponding value of the evaluation function;

[0064] Fig.14This is the imaging result after automatic focusing;

[0065] Markings in the figure are: 1 is the lens barrel, 2 is the guide rod, 3 is the motor mounting seat, 4 is the servo motor, 5 is the driving wheel, 6 is the connecting sleeve, 7 is the second threaded screw, 8 is the guide block, 9 is the industrial camera CCD, 10 is the sparse aperture imaging system, and 11 is the first threaded screw. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the protection content of the present invention.

[0067] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention; the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance. In addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] like Figures 7 to 9 As shown, an automatic focusing sparse aperture imaging system includes a sparse aperture imaging system 10 and an automatic focusing system, wherein the automatic focusing system is arranged at the observation end of the sparse aperture imaging system 10, and further includes an image processing system and an algorithm control system;

[0069] The image processing system is used to receive the target image sent by the sparse aperture imaging system 10, and process and transmit it to the algorithm control system;

[0070] The algorithm control system generates a control voltage to control the automatic focusing system according to the processing result of the image processing system.

[0071] The purpose of this design is to process the target image collected by the sparse aperture imaging system through the image processing system at the control method level, and control the automatic focusing system in combination with the algorithm control system, thereby achieving automatic focusing.

[0072] Meanwhile, in this embodiment, the automatic focusing system includes a lens barrel 1, a focusing power mechanism, a focusing limit mechanism and an industrial camera CCD9;

[0073] One end of the lens barrel 1 is connected to the observation end of the sparse aperture imaging system 10;

[0074] The focusing power mechanism and the focusing limit mechanism are both arranged at the other end of the lens barrel 1, and the focusing power mechanism can be controlled by the automatic focusing method to drive the focusing limit mechanism to move;

[0075] The industrial camera CCD9 is arranged at one end of the focus limiting mechanism, and the industrial camera CCD9 can move linearly on the focus limiting mechanism.

[0076] The purpose of such design is to set up an automatic focusing system including a lens barrel, a focusing power mechanism, a focusing limit mechanism and an industrial camera CCD at the structural level, wherein the focusing power mechanism includes components such as a servo motor and a driving wheel, and the focusing limit mechanism includes a double-thread mechanism, which can be driven by the servo motor to rotate the driving wheel, and the driving wheel drives the nut of the double-thread mechanism to rotate to move the industrial camera CCD, and at the same time, realize automatic focusing through an adaptive control algorithm. This solves the problem that the existing sparse aperture imaging system has no automatic focusing system, and the focus position will change due to the different distances between the observed object and the imaging system, requiring personnel to perform manual focusing.

[0077] In this embodiment, the focusing power mechanism includes a motor mounting seat 3, a servo motor 4 and a driving wheel 5, wherein the motor mounting seat 3 is arranged at the other end of the lens barrel 1;

[0078] The servo motor 4 is mounted on the motor mounting base 3, and the servo motor 4 is connected to the controller signal;

[0079] The driving wheel 5 is connected to the power output end of the servo motor 4, and the driving wheel 5 can drive the focus limiting mechanism to move.

[0080] The focus limiting mechanism comprises a first threaded screw 11, a connecting sleeve 6 and a second threaded screw 7;

[0081] The first threaded screw 11 is connected to the other end of the lens barrel 1 and is disposed below the motor mounting seat 3;

[0082] One end of the connecting sleeve 6 is connected to the first threaded screw 11, and the other end of the connecting sleeve 6 is connected to the second threaded screw 7, and the outer periphery of the connecting sleeve 6 can mesh with the driving wheel 5;

[0083] The industrial camera CCD9 is arranged on the second threaded screw 7.

[0084] Furthermore, the first threaded screw 11 and the second threaded screw 7 are both hollow tube structures.

[0085] At the same time, the outer circumference of the first threaded screw 11 is a reverse external thread, the outer circumference of the second threaded screw 7 is a forward external thread, the end of the connecting sleeve 6 facing the first threaded screw 11 is provided with a reverse internal thread, and the end of the connecting sleeve 6 facing the second threaded screw 7 is provided with a forward internal thread.

[0086] Furthermore, the focus limiting mechanism also includes a guide rod 2 and a guide block 8;

[0087] The guide rod 2 is connected to the other end of the lens barrel 1 and is disposed below the first threaded screw 11;

[0088] The guide block 8 is sleeved on the guide rod 2 , and the guide block 8 is connected to the industrial camera CCD 9 .

[0089] In actual use, the servo motor 4 drives the driving wheel 5 to rotate, and the driving wheel 5 drives the convex teeth on the outer periphery of the connecting sleeve 6 to rotate. The rotation of the connecting sleeve 6 can drive the second threaded screw 7 to produce rotation or linear motion. The industrial camera CCD9 is fixedly connected to the second threaded screw, and the industrial camera CCD9 can also produce rotation or linear motion accordingly.

[0090] At the same time, in order to ensure that the industrial camera CCD9 only produces linear motion, a guide block 8 is connected to the industrial camera CCD9, and the guide block 8 is guided by the guide rod 2, so that the industrial camera CCD9 can only produce linear motion, thereby achieving the purpose of focusing, and because the second threaded screw, the first threaded screw and the connecting sleeve are all hollow structures, light can pass through them and be projected into the industrial camera CCD9.

[0091] Furthermore, when the servo motor 4 rotates forward, it drives the driving wheel 5 to rotate, and the driving wheel 5 drives the connecting sleeve 6 to rotate. The rotation of the connecting sleeve 6 drives the second threaded screw 7 to make a linear motion, and the industrial camera CCD9 moves away from the lens barrel 1 along the guide rod through the guide block.

[0092] When the servo motor 4 rotates in the reverse direction, it drives the driving wheel 5 to rotate, and the driving wheel 5 drives the connecting sleeve 6 to rotate. The rotation of the connecting sleeve 6 drives the second threaded screw 7 to make a linear motion, and the industrial camera CCD9 approaches the lens barrel 1 along the guide rod through the guide block.

[0093] In this embodiment, a sparse aperture imaging system automatic focusing method is provided, comprising the following steps:

[0094] S1. Capturing an image of the target object through a sparse aperture imaging system 10, and transmitting the captured image to an image processing system;

[0095] S2. The image processing system normalizes the image and generates a performance evaluation function J;

[0096] S3. The algorithm control system iterates the performance evaluation function J and controls the voltage of the automatic focusing system according to the iteration result;

[0097] S4. In the automatic focusing system, the servo motor 4 adjusts the position of the industrial camera CCD9 according to the control voltage to achieve automatic focusing.

[0098] The purpose of this design is that the automatic focusing algorithm of the sparse aperture imaging system uses the imaging clarity as the optimization target and uses the optimization iteration to calculate the driving voltage of the servo motor. The control process is as follows: Fig.10 shown.

[0099] The square sum of the normalized imaging surface grayscale values ​​is selected as the performance evaluation function J, and its expression is:

[0100] ;

[0101] In the formula, is the imaging surface coordinate, is the ideal image grayscale value, is the actual image grayscale value.

[0102] The existing SPGD algorithm uses fixed gain coefficients and disturbance amplitudes, which leads to slow iteration speed, low stability, and difficulty in real-time parameter adjustment in practical applications. For sparse aperture imaging systems, the gain coefficient is adaptively adjusted based on variable gain, and a gradient second-order momentum control algorithm is introduced to improve the convergence speed and accuracy of the system. The momentum of the gradient is continuously accumulated during the iteration process to reduce the fluctuation of the gradient descent, thus realizing an adaptive gain momentum SPGD algorithm.

[0103] The iterative formula of the algorithm is:

[0104] ;

[0105] In the formula, u is the driving voltage of the autofocus system, k is the number of iterations, and u is k is the adjustment voltage during the kth adjustment, u k-1 is the regulation voltage during the k-1th regulation, To impose The performance evaluation indicators after To impose The performance evaluation indicators after represents the amplitude of random disturbances that follow Bernoulli distribution, is the first-order corrected momentum of the gradient, is the second-order corrected momentum of the gradient, c1, c2 are constant parameters, is the initial gain coefficient, is a micro-valued constant;

[0106] In progress At the iteration, the first-order corrected momentum and second-order corrected momentum of the calculated gradient are:

[0107] ;

[0108] ;

[0109] ;

[0110] ;

[0111] In the formula, m gk is the first-order momentum of the gradient at the kth iteration, is the first-order momentum of the gradient at the k-1th iteration, and its initial value is 0; v gk is the second-order momentum of the gradient; is the estimated value of the gradient at the kth iteration; is the square of the estimated gradient at the kth iteration; , is the momentum factor.

[0112] Image result before autofocus Fig.12 For example, the current evaluation value J can be calculated through the performance evaluation function J 1 =0.24, at this time m gk The initial value of the first-order momentum of the gradient is 0, and the initial voltage u is given 0 =1v, press Fig.11 The calculated voltage u can be obtained by the process k , voltage u k That is the control voltage of the servo motor 4.

[0113] In the actual control system, automatic focusing is achieved through a PID controller. The controlled object is the performance evaluation function J, the controlled quantity is the displacement of the lens optical axis, and the given input is the control voltage u k The range of the performance evaluation function J from 0 to 1 is linearly expressed as the control voltage range of -5 V to +5 V, and the displacement range of the intermediate transfer process corresponding to the lens optical axis direction is -10 mm to +10 mm. k The difference between the controlled quantity performance evaluation function J is the deviation e, which is used as an error signal input to drive the motor to rotate. The motor rotation drives the drive wheel to rotate, which in turn drives the focus limit mechanism to move, and the entire system can achieve the purpose of automatic focusing. The entire automatic focusing process is the process of eliminating the influence of the deviation e.

[0114] The rotation of the servo motor 4 drives the driving wheel 5 to rotate, and the driving wheel 5 drives the connecting sleeve driven wheel 6 to rotate. The rotation of the connecting sleeve driven wheel 6 can drive the second threaded screw 7 to produce linear motion, and drive the industrial camera CCD9 to move back and forth to achieve focusing. After each iteration, an adjusted evaluation function J will be obtained. k The relationship between the number of iterations and the evaluation function is as follows: Fig.13 The algorithm converges to the maximum value after about 90 iterations, and the imaging result after focusing is as follows Fig.14 As shown, the evaluation value J 90 =0.92.

[0115] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An automatic focusing sparse aperture imaging system, comprising a sparse aperture imaging system (10) and an automatic focusing system, wherein the automatic focusing system is arranged at an observation end of the sparse aperture imaging system (10), and is characterized in that: It also includes image processing system and algorithm control system; The image processing system is used to receive the target image sent by the sparse aperture imaging system (10), process it and transmit it to the algorithm control system; The algorithm control system generates a control voltage to control the automatic focusing system according to the processing result of the image processing system.

2. The automatic focusing sparse aperture imaging system according to claim 1, characterized in that: The automatic focusing system comprises a lens barrel (1), a focusing power mechanism, a focusing limit mechanism and an industrial camera CCD (9); One end of the lens barrel (1) is connected to an observation end of a sparse aperture imaging system (10); The focusing power mechanism and the focusing limit mechanism are both arranged at the other end of the lens barrel (1), and the focusing power mechanism can be controlled by an automatic focusing method to drive the focusing limit mechanism to move; The industrial camera CCD (9) is arranged at one end of the focus limiting mechanism, and the industrial camera CCD (9) can move linearly on the focus limiting mechanism.

3. The automatic focusing sparse aperture imaging system according to claim 2, characterized in that: The focusing power mechanism comprises a motor mounting seat (3), a servo motor (4) and a driving wheel (5); the motor mounting seat (3) is arranged at the other end of the lens barrel (1); The servo motor (4) is mounted on the motor mounting seat (3), and the servo motor (4) is connected to the controller signal; The driving wheel (5) is connected to the power output end of the servo motor (4), and the driving wheel (5) can drive the focus limiting mechanism to move.

4. The automatic focusing sparse aperture imaging system according to claim 3, characterized in that: The focus limiting mechanism comprises a first threaded screw (11), a connecting sleeve (6) and a second threaded screw (7); The first threaded screw (11) is connected to the other end of the lens barrel (1) and is arranged below the motor mounting seat (3); One end of the connecting sleeve (6) is connected to the first threaded screw (11), the other end of the connecting sleeve (6) is connected to the second threaded screw (7), and the outer periphery of the connecting sleeve (6) can mesh with the driving wheel (5); The industrial camera CCD (9) is arranged on the second threaded screw (7).

5. The automatic focusing sparse aperture imaging system according to claim 4, characterized in that: The first threaded screw (11) and the second threaded screw (7) are both hollow tube structures.

6. The automatic focusing sparse aperture imaging system according to claim 4, characterized in that: The outer circumference of the first threaded screw (11) is a reverse external thread, the outer circumference of the second threaded screw (7) is a forward external thread, the end of the connecting sleeve (6) facing the first threaded screw (11) is internally provided with a reverse internal thread, and the end of the connecting sleeve (6) facing the second threaded screw (7) is internally provided with a forward internal thread.

7. The automatic focusing sparse aperture imaging system according to claim 4, characterized in that: The focus limiting mechanism further comprises a guide rod (2) and a guide block (8); The guide rod (2) is connected to the other end of the lens barrel (1) and is arranged below the first threaded screw rod (11); The guide block (8) is sleeved on the guide rod (2), and the guide block (8) is connected to the industrial camera CCD (9).

8. A method for automatic focusing of a sparse aperture imaging system, implemented based on the automatic focusing sparse aperture imaging system of any one of claims 5 to 7, characterized in that: The following steps are involved: S1. Capturing an image of a target object through a sparse aperture imaging system (10), and transmitting the captured image to an image processing system; S2. The image processing system normalizes the image and generates a performance evaluation function J; S3. The algorithm control system iterates the performance evaluation function J and controls the voltage of the automatic focusing system according to the iteration result; S4. In the automatic focusing system, the servo motor (4) adjusts the position of the industrial camera CCD (9) according to the control voltage to achieve automatic focusing.

9. The automatic focusing method of a sparse aperture imaging system according to claim 8, characterized in that: In S2, the expression of the performance evaluation function J is: ； In the formula, is the imaging surface coordinate, is the ideal image grayscale value, is the actual image grayscale value.

10. The automatic focusing method of a sparse aperture imaging system according to claim 9, characterized in that: In S3, the iteration formula is: ； In the formula, u is the driving voltage of the autofocus system, k is the number of iterations, and u is k is the adjustment voltage during the kth adjustment, u k-1 is the regulation voltage during the k-1th regulation, To impose The performance evaluation indicators after To impose The performance evaluation indicators after represents the amplitude of random disturbances that follow Bernoulli distribution, is the first-order corrected momentum of the gradient, is the second-order corrected momentum of the gradient, c1, c2 are constant parameters, is the initial gain coefficient, is a micro-valued constant; In progress At the iteration, the first-order corrected momentum and second-order corrected momentum of the calculated gradient are: ； ； ； ； In the formula, m gk is the first-order momentum of the gradient at the kth iteration, is the first-order momentum of the gradient at the k-1th iteration, and its initial value is 0; v gk is the second-order momentum of the gradient; is the estimated value of the gradient at the kth iteration; is the square of the estimated gradient at the kth iteration; , is the momentum factor.

Images