CN113237634B - Zoom lens automatic image surface butt joint and optical axis run-out detection system and method - Google Patents

Abstract

The invention relates to the field of image plane debugging of an aerospace full-spectrum zoom lens, in particular to a zoom lens automatic image plane connection and optical axis jump detection system and method, which solves the problem that the existing image plane connection method consumes a lot of labor and requires different batches of There may be differences in image clarity of sub-products and individual differences in optical axis beat detection, and the efficiency is not high. The system includes a system support bracket, a drive and feedback assembly, a guide assembly, an optical imaging assembly and a control assembly. The drive and feedback components include potentiometers, motors, potentiometer gears, motor gears, drive screw gears, couplings, ball screw nuts, and nut mounting brackets. The guide assembly includes linear guides, moving sliders and zoom lens mounting brackets. The optical imaging assembly includes an imaging assembly, an imaging assembly mounting bracket, two four-degree-of-freedom optical adjustment platforms, a collimator and accessories, and a zoom lens. Control components include control box, upper computer and video display.

Description

A zoom lens automatic image plane contact and optical axis jump detection system and method

technical field

The invention relates to the field of image plane debugging of full-spectrum zoom lenses in aerospace, in particular to a zoom lens automatic image plane connection and optical axis jump detection system and a method for using the same.

Background technique

Existing image plane contact methods are generally divided into two categories. The first type of artificial image plane contact method is to continuously correct the thickness of the image plane trimming pad to find the position of the clear image plane. This method requires at least 2 -3 people work at the same time, which is relatively labor-intensive, and the image clarity of different batches of products may vary. The second type is the semi-automatic image plane connection method. This method can be driven by a motor to realize image plane connection. Compared with artificial image plane connection, the image plane connection efficiency of this method is improved. In terms of clear judgment, multiple people are also required to participate in the work, and there may be some differences in the image clarity of different batches of products. In addition, the existing optical axis beating detection methods are all manual detection, and there are individual differences in the individual judgment of the number of beating pixels, and the detection efficiency is not high.

content of invention

The purpose of the present invention is to solve the problems that the existing image plane connection method consumes a lot of labor, and there may be differences in the image plane clarity of different batches of products, and there are individual differences in optical axis jump detection, and the efficiency is not high, and provides a zoom A system and method for detecting lens automatic image plane contact and optical axis runout.

For achieving the above object, the technical scheme provided by the present invention is as follows:

A zoom lens automatic image plane contact and optical axis jump detection system, which is special in that it includes a system support bracket, a drive and feedback component, a guide component, an optical imaging component and a control component;

The drive and feedback assembly is arranged on the system support bracket, and includes a potentiometer, a motor, a potentiometer gear, a motor gear, a transmission screw gear, a coupling, a ball screw nut and a nut fixing bracket;

The potentiometer input is connected to the potentiometer gear; the motor output is connected to the motor gear to drive the motor gear to rotate; the motor gear is meshed with the transmission screw gear to drive the transmission screw gear; the transmission wire The rod gear meshes with the potentiometer gear for driving the potentiometer gear;

The transmission screw gear is connected with the ball screw nut through a coupling to realize the movement of the ball screw nut, and the ball screw nut is connected with the zoom lens mounting bracket through the nut fixing bracket to realize the movement of the zoom lens mounting bracket;

The guide assembly includes two linear guide rails, two moving sliders and a zoom lens mounting bracket; the two linear guide rails are installed on the system support bracket in parallel, and limit screws are arranged on the linear guide rails, and the limit screws are used to limit the zoom lens The displacement of the mounting bracket; the moving slider is arranged on the linear guide rail, and the moving slider is fixedly connected with the zoom lens mounting bracket;

The optical imaging assembly includes an imaging assembly, an imaging assembly mounting bracket, two four-degree-of-freedom optical adjustment platforms, a collimator and accessories, and a zoom lens;

The imaging component is installed on the four-degree-of-freedom optical adjustment platform through the imaging component mounting bracket, and the collimator and accessories are installed on the plane of another four-degree-of-freedom optical adjustment platform, and this four-degree-of-freedom optical adjustment platform is installed on the system support bracket The zoom lens is mounted on the zoom lens mounting bracket; the four-degree-of-freedom optical adjustment platform is used to adjust the collimator, the zoom lens and the optical axis of the imaging component to be coaxial;

The control assembly includes a control box, a host computer and a video display; the host computer is installed with host computer software; the control box is connected with a potentiometer, a motor, a zoom lens and the host computer for recording the angular displacement information of the potentiometer, zooming The long-focus or short-focus state of the lens, control the work of the motor, and transmit the information to the host computer; the video display is connected with the host computer and the imaging component to display the image information of the imaging component at different positions.

Further, the drive and feedback assembly also includes a front screw rod fixing bracket, a screw rod rear fixing bracket and an assembly mounting bracket;

The front end of the coupling is installed on the front fixing bracket of the screw rod through an angular contact bearing, the rear end is connected with the screw rod of the ball screw nut, and the other end of the screw rod of the ball screw nut is installed on the screw rod through an angular contact bearing. On the rear fixing bracket of the rod, the front fixing bracket of the screw rod is fixedly connected with the rear fixing bracket of the screw rod;

The potentiometer, the motor and the front fixing bracket of the screw rod are all installed on the component installation bracket, and the component installation bracket is fixed on the system support bracket.

Further, a trimming pad is installed at the screw connection between the component mounting bracket and the system support bracket to adjust the posture of the drive and feedback components.

Further, the potentiometer gear and the transmission screw gear adopt double gear meshing transmission, the transmission backlash is less than 0.18°, and the feedback error is less than 5.4°;

The potentiometer gear includes a first potentiometer gear and a second potentiometer gear that mesh with the drive screw gear at the same time; the first potentiometer gear and the second potentiometer gear are coaxially installed, and the first potentiometer gear and the second potentiometer gear The teeth of the potentiometer gear are circumferentially staggered.

Further, the transmission ratio of the transmission screw gear to the potentiometer gear is 3.4375, the number of gears of the transmission screw gear is 110, the number of gears of the first potentiometer gear and the second potentiometer gear is 32, and the modulus is 0.25.

At the same time, the present invention also provides an automatic image plane contact and optical axis jump detection method of a zoom lens, which is special in that it includes the following steps:

Step 1: Install the automatic image plane connection and optical axis jump detection system of the zoom lens;

Step 2: The zoom lens is automatically connected to the image plane;

1) The automatic image plane connection of the zoom lens and the optical axis beat detection system are powered on, and the collimator selects the discrimination rate target and initializes it;

2) Determine whether the flange surface of the zoom lens and the flange surface of the imaging assembly are flat and have no protrusions;

2.1) If there is a bulge between the flange surface of the zoom lens and the flange surface of the imaging assembly, install a gasket with a thickness of d between the zoom lens and the flange of the imaging assembly to avoid bumps collision, and perform initialization, and then go to step 2.2) ;

If the flange surface of the zoom lens and the flange surface of the imaging assembly are flat and have no protrusions, then d=0, go to step 2.2);

2.2) The drive and feedback components run until the flange of the zoom lens and the camera flange are attached, and the upper computer software records the angular displacement information D1 of the potentiometer at this time; at this time, the running direction of the drive and feedback components is the positive direction;

3) Determine whether the zoom lens has the clearest position in the short focus;

3.1) The zoom lens is switched to the short-focus state, and the initial position of the focusing component on the zoom lens is the theoretical design position of the zoom lens, and one-key focusing is selected at this time; the one-key focusing command is completed on the host computer;

3.2) The drive and feedback components drive the zoom lens to move to the raised limit screw in the opposite direction. During the movement of the zoom lens, the image information is uploaded to the display and the host computer software in real time, and the host computer software calculates and compares the image grayscale variance value and;

3.3) Judging whether there is a maximum value of the sum of the gray-scale variance values during the movement process, and the maximum value of the sum of the gray-scale variance values is not located at the position of the limit screw of the mechanical limit;

If the maximum value of the gray-scale variance value is at the mechanical limit position, it is beyond the working range of the system; at this time, the system is powered off, and the mechanical limit function of the raised limit screw (24) in step 3.2) is cancelled, and the The other limit screw (24) is changed to a raised state, and after the mechanical limit is achieved, perform step 1);

If there is a maximum value of the sum of the grayscale variance values, and the maximum value of the sum of the grayscale variance values is not located at the mechanical limit position;

a) The host computer software judges that the zoom lens has the clearest short focus position, and the drive and feedback components drive the zoom lens to run to this position;

b) Check whether the image is clear;

If it is clear, output the image plane position information D2 at this time;

If it is not clear, manually adjust the drive and feedback components by means of manual focusing + and focusing - until the zoom lens (22) moves to the clearest position, and then output the image plane position information D2 at this time;

4) Determine whether the zoom lens has the clearest position at the telephoto position;

4.1) Drive the zoom lens to switch to the telephoto position;

4.2) Determine whether the telephoto of the zoom lens is the clearest position;

If the telephoto of the zoom lens is not the clearest position, use one-key focus to focus the zoom lens (22) focusing assembly to the clearest position, and then jump to step 3.1);

If the telephoto of the zoom lens is the clearest position, the image surface position information D2 at this time is output, and the actual thickness of the trimming pad on the image surface of the zoom lens (22) is D2-D1+d; at this time, the telephoto of the zoom lens (22) When both the short focus and the short focus are in the clearest position, the image plane is completed;

Step 3: Automatic Optical Axis Runout Detection of Zoom Lenses

1) The collimator uses a crosshair target to accurately measure the runout;

2) Adjust the optical axis of the collimator through the four-degree-of-freedom optical adjustment platform, and the long and short focus of the zoom lens are coaxial;

3) According to the image plane connection result, set the position of the drive and feedback components. At this time, both the long and short focal positions of the zoom lens can be clearly imaged;

4) The zoom lens is switched to the telephoto state, and the reticle at the center of the target surface of the imaging component is coincident with the optical axis of the telephoto state through the four-degree-of-freedom optical platform;

5) Through the image processing algorithm of the host computer software, record the optical axis position of the zoom lens at this time, and this position is the initial position;

6) Slowly drive the zoom lens to switch from the telephoto to the short-focus state. The host computer software records the optical axis position of each focal length during the switching process, and identifies the optical axis point calibrated on the image frame by frame and the center of the imaging component target surface at different focal lengths. The difference Δx and Δy between the reticle, so as to obtain the optical axis runout parameter of the zoom lens switching from the telephoto end to the short focal end; the Δx is the transverse direction between the optical axis point and the reticle at the center of the target surface of the imaging assembly Difference, Δy is the longitudinal difference between the optical axis point and the reticle in the center of the target surface of the imaging assembly;

7) Use the same method as step 6) to measure the optical axis jump parameter of the zoom lens switched from the short focal end to the long focal end; at this time, the automatic optical axis jump detection of the zoom lens is completed.

Further, the collimated light pipe is replaced with a black body, which is suitable for the image plane connection and the optical axis jump detection process of the infrared optical lens.

Further, step 1 also includes detecting the running stability of the automatic image plane contact of the zoom lens and the optical axis jump detection system, and the specific steps are as follows:

1) Install the drive and feedback components, guide components and control box;

2) Detect the running stability of the automatic image plane connection of the zoom lens and the optical axis jump detection system;

2.1) Fix the system support bracket on the optical platform, and paste a flat reflector near the position where the zoom lens mounting bracket is installed with the zoom lens;

Adjust the zoom lens mounting bracket to the limit screw closest to the installation position of the imaging assembly, and record the position as S at this time;

2.2) Place the self-collimation theodolite on the front end of the plane mirror, and adjust the self-collimation theodolite to make the crosshair coincide with its self-collimating image, and record the elevation angle θ and azimuth angle σ of the theodolite at this time;

2.3) The drive and feedback components are powered on and run, fine-tune the theodolite pitch angle and azimuth angle so that the autocollimation image coincides with the reticle differentiation line inside the theodolite, and record the movement amount L ₁ of the zoom lens mounting bracket, the theodolite pitch angle θ ₁ and Azimuth σ ₁ ;

Calculate Δθ=θ ₁ -θ, Δσ=σ ₁ -σ;

2.4) Repeat step 2.3) until the zoom lens moves to the limit position;

According to the above test data, combined with zoom lenses and imaging components with different focal lengths and pixel sizes, determine whether the running stability meets the requirements;

If it does not meet the requirements, the guide assembly can choose a higher-precision linear guide, or increase the length of the moving slider on the linear guide to reduce the pose change caused by the movement gap; then go to step 2);

If the requirements are met, the automatic image plane connection of the zoom lens and the smoothness detection of the optical axis runout detection system are completed;

3) Install the remaining components.

The present invention has the following advantages:

1. Avoid the difference in the image clarity of different batches of products and the discrimination error in the detection of optical axis runout. Using this system, through the change of the position of the zoom lens in the process of automatic object docking, the host computer software calculates and compares the sum of the variance value of the image grayscale in real time, judges whether there is the clearest position, and rechecks whether it is the clearest, with multiple iterations Determine the clearest position information at the same time with long and short focus, thus liberating part of manpower and achieving the goal of improving assembly accuracy and efficiency. In addition, the image processing algorithm is consistent, and the image clarity of different batches of products is the same. In addition, the optical axis jump detection is carried out through this system, and the position of the optical axis of each focal length during the switching process is recorded by the host computer software, and the optical axis point calibrated on the image is identified frame by frame at different focal lengths. The difference between the optical axis jump parameters of the zoom lens can be obtained, which can avoid the discrimination error caused by manual detection and improve the detection efficiency.

2. The automatic image plane connection process is stable and the reliability is high. During the installation process, the running stability of the system is detected to improve the stability of the system. In addition, there are four limit screws on the linear guide rail to prevent the slider of the guide rail from moving to the limit position and falling off, improving the reliability of the system, and at the same time, it can also adjust the working range of the image plane system.

3. Wide range of use. The system has a simple structure, easy operation and simple control. When the zoom lens is installed, it is widely used in the work of various aerospace photoelectric loads by designing different installation interfaces (ie zoom lens mounting brackets). The system can be used as a module. , easy to disassemble and install, the whole machine can be installed as a module to any occasion to work on the image surface through the mounting screws; if the collimator is a black body, the system can be applied to the process of the image surface of the infrared optical zoom lens; the image The surface system can also be applied to the fixed-focus lens image-facing process.

4. The system does not need to consider the axial force of the motor, avoids the limitation of the axial force on the output torque of the bearing, and optimizes the transmission ratio of the motor gear and the transmission screw gear, which can improve the motor output torque.

5. High positioning accuracy. Through the four-degree-of-freedom optical adjustment platform, the optical axis of the collimator, the optical axis of the zoom lens and the optical axis of the imaging component are adjusted to coincide, so as to avoid the clear and uneven image surface caused by the inclination of the target surface during the process of image contact. Improve the judgment accuracy of the image plane meeting the clear image plane.

Description of drawings

1 is a schematic diagram of an embodiment of a zoom lens automatic image plane interface and optical axis jump detection system embodiment of the present invention;

2 is a schematic diagram of a drive and feedback assembly in an embodiment of the present invention;

3 is a schematic diagram of a guide assembly in an embodiment of the present invention;

4 is a schematic diagram of the meshing of the potentiometer gear and the drive screw gear in the embodiment of the present invention;

5 is a schematic diagram of the stability detection of the automatic image plane connection of the zoom lens and the optical axis jump detection system during the installation process in the embodiment of the method of the present invention;

Fig. 6 is the working flow chart of zoom lens automatic image plane connection in the method embodiment of the present invention;

The reference numbers are as follows:

1-system support bracket, 2-potentiometer, 3-motor, 4-potentiometer gear, 41-first potentiometer gear, 42-second potentiometer gear, 5-motor gear, 6-drive screw gear, 7 -Coupling, 8-ball screw nut, 9-nut fixing bracket, 10-screw front fixing bracket, 11-screw rear fixing bracket, 12-component mounting bracket, 13-angular contact bearing, 14-zoom Lens mounting bracket, 15-linear guide, 16-moving slider, 18-imaging assembly, 19-imaging assembly mounting bracket, 20-four-DOF optical adjustment platform, 21- collimator and accessories, 22-zoom lens, 23 - Control box, 24- Limit screw, 29- Auto-collimation theodolite, 30- Plane mirror.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings.

As shown in Figure 1, an automatic image plane contact and optical axis jump detection system of a zoom lens includes a system support bracket 1, a drive and feedback component for providing power and feedback for the mechanism, a guide component for ensuring the moving direction of the imaging component, an optical component Imaging components and control components.

As shown in Figure 2, the drive and feedback assembly is arranged on the system support bracket 1, including potentiometer 2, motor 3, potentiometer gear 4, motor gear 5, transmission screw gear 6, coupling 7, ball screw nut 8 and the nut to fasten the bracket 9. Among them, the output of the motor 3 is connected to the motor gear 5, which is used to drive the motor gear 5 to rotate, the motor gear 5 is meshed with the transmission screw gear 6, and is used to drive the transmission screw gear 6, and the transmission screw gear 6 is meshed with the potentiometer gear 4. It is used to drive the potentiometer gear 4, and the potentiometer gear 4 is connected to the output of the potentiometer 2. The drive screw gear 6 is connected with the ball screw nut 8 through the coupling 7 to realize the movement of the ball screw nut 8, and the ball screw nut 8 is connected with the zoom lens mounting bracket 14 through the nut fixing bracket 9 to realize the zoom lens installation. Movement of the stand 14 .

The present invention further optimizes and improves the driving and anti-driving components as follows.

As shown in FIG. 2 , the drive and feedback assembly further includes a front screw fixing bracket 10 , a rear screw fixing bracket 11 and an assembly mounting bracket 12 . The front end of the coupling 7 is installed on the front fixing bracket 10 of the lead screw through the angular contact bearing 13, the rear end is connected with the lead screw of the ball screw nut 8, and the other end of the lead screw of the ball screw nut 8 is installed through the angular contact bearing 13. On the screw rear fixing bracket 11 , the screw front fixing bracket 10 is fixedly connected with the screw rear fixing bracket 11 . The potentiometer 2 , the motor 3 and the front fixing bracket 10 of the screw rod are all mounted on the component mounting bracket 12 , and the component mounting bracket 12 is fixed on the system support bracket 1 .

In order to adjust the posture of the drive and feedback assembly, a trimming pad is installed at the screw connection between the assembly mounting bracket 12 and the system support bracket 1 .

As shown in FIG. 4 , the potentiometer gear 4 and the transmission screw gear 6 are driven in a double meshing manner, including a first potentiometer gear 41 and a second potentiometer gear 42 that mesh with the transmission screw gear 6 at the same time. The gear 41 and the second potentiometer gear 42 are coaxially installed, and the gear teeth of the first potentiometer gear 41 and the second potentiometer gear 42 are staggered in the circumferential direction, so that the transmission backlash is less than 0.18°, and the feedback error is less than 5.4°. Consider the feedback accuracy and control error of three thousandths, that is, 360*5*0.003=5.4°, and consider the principle of maximizing the transmission ratio of the transmission screw gear 6 and the potentiometer gear 4.

The transmission ratio of the transmission screw gear 6 and the potentiometer gear 4 is 3.4375, the number of gears of the transmission screw gear 6 is 110, the number of gears of the first potentiometer gear 41 and the second potentiometer gear 42 are both 32, and the modulus is 0.25, then the transmission screw gear 6 is converted to 1.6°, the total control accuracy is 1.78°, the potentiometer 2 rotates once, and the moving slider 16 moves 2.5mm, the control accuracy is about 0.01mm.

As shown in FIG. 3 , the guide assembly includes two linear guide rails 15 , two moving sliders 16 and a zoom lens mounting bracket 14 that can adapt to various mounting interfaces. Two linear guide rails 15 are installed on both sides of the system support bracket 1 in parallel, and the moving slider 16 is arranged on the linear guide rails 15 and is fixedly connected with the zoom lens mounting bracket 14 . The zoom lens mounting bracket 14 moves the moving slider 16 on the linear guide 15 under the driving of the driving and feedback assembly. The linear guide 15 described above is a THK linear guide.

In order to prevent the moving slider 16 from moving to the limit position and falling off, the guide assembly is designed with an adjustable mechanical limit, that is, the linear guide 15 is provided with four limit screws 24, which are used to limit the displacement of the zoom lens mounting bracket 14, and also The working range of the object plane system can be adjusted.

As shown in FIG. 1 , the optical imaging assembly includes an imaging assembly 18 , an imaging assembly mounting bracket 19 , two four-degree-of-freedom optical adjustment platforms 20 , a collimator and accessories 21 and a zoom lens 22 . The imaging assembly 18 is installed on the four-degree-of-freedom optical adjustment platform 20 through the imaging assembly mounting bracket 19, the collimator and accessories 21 are installed on the system support bracket 1 through another four-degree-of-freedom optical adjustment platform 20, and the zoom lens 22 is installed on the zoom lens. On the mounting bracket 14 , the optical axes of the collimator and the collimator of the accessory 21 , the zoom lens 22 and the imaging assembly 18 are coaxial through two four-degree-of-freedom optical adjustment platforms 20 . When adjusting the optical axis of the collimator, the zoom lens 22 and the imaging assembly 18 to be coaxial, the collimator uses a crosshair target.

Taking the right-handed coordinate system as the criterion, the lifting direction of the four-DOF optical adjustment platform 20 is the Z direction, the direction parallel to the optical axis is the Y direction, and the rest is the X direction. The Z direction is the first degree of freedom, the rotation angle around the X axis is the second degree of freedom, the rotation angle around the Y axis is the third degree of freedom, and the rotation angle around the Z axis is the fourth degree of freedom. The liquid can be changed by translating the optical adjustment stage along the X, Y axis, changing the fifth and sixth degrees of freedom.

The control assembly includes a control box 23, a host computer and a video display. The upper computer is installed with the upper computer software, and the control box 23 is connected with the potentiometer 2, the motor 3, the zoom lens 22 and the upper computer, to record the angular displacement information of the potentiometer 2, the telephoto or short focus state of the zoom lens 22, and control the motor. 3 work, and transmit the information to the host computer software. The video display displays image information of the imaging imaging assembly 18 at various locations.

The assembly of the automatic image plane connection of the zoom lens 22 and the optical axis jump detection system is specifically carried out according to the following steps:

1. Install the drive and feedback components

1.1) Connect the ball screw nut 8 to the nut fixing bracket 9 through 4 M3X6 cylinder head screws, the ball screw nut 8 and the coupling 7 are fixed, and the screws are glued.

1.2) Install the angular contact bearing 13 on the corresponding positions of the front fixing bracket 10 of the screw rod and the rear fixing bracket 11 of the screw rod to ensure that the angular contact bearing 13 is pressed tightly without movement.

1.3) Install the component completed in step 1.2) in the corresponding position of the component completed in step 1.1), and press the angular contact bearing 13 and the coupling 7 tightly to ensure that there is no movement.

1.4) Fasten the front screw fixing bracket 10 and the rear screw fixing bracket 11 with 3 M3X6 cylinder head screws, and make sure that the ball screw nut 8 passes through the angle between the screw rear fixing bracket 11 and the screw rear fixing bracket 11. Contact the bearing 13 and press it tightly to ensure that the angular contact bearing 13 is installed in place without play and the screws are glued.

1.5) Install the component completed in step 1.4) on the component mounting bracket 12 with 6 M3X6 cylinder head screws, then install the drive screw gear 6, and install the screws with glue.

1.6) Install the motor 3, motor gear 5, potentiometer 2 and potentiometer gear 4 to the corresponding positions of the completed components in step 1.5) to ensure that the potentiometer gear 4, motor gear 5 and drive screw gear 6 run smoothly, and the drive is The feedback assembly is assembled.

2. Install the guide assembly

2.1) Install the nut fixing bracket 9 to the zoom lens mounting bracket 14 through 4 M4 screws, and install the screws with glue.

2.2) Install the two linear guide rails 15 to the corresponding positions of the system support bracket 1 to ensure the parallelism of the guide rails. There are 4 limit screws 24 at both ends of the linear guide rail 15, and the moving slider 16 is installed on the linear guide rail 15.

2.3) Install the zoom lens mounting bracket 14 in step 2.1) on the moving slider 16 in step 2.2) through 8 M2 screws, and ensure that the moving slider 16 runs smoothly and the guide assembly is installed.

3. Adjust the installation posture of the drive and feedback components

By adjusting the thickness of the trimming pad, install the component mounting bracket 12 at the corresponding position of the system support bracket 1, and at the same time ensure that the linear guide slider runs smoothly.

4. Install the remaining components

4.1) Install the control box 23.

4.2) Install the zoom lens 22 , the four-DOF optical adjustment platform 20 , the imaging assembly mounting bracket 12 and the imaging assembly 18 .

4.3) Connect the video display and the host computer software.

4.4) Install the four-degree-of-freedom optical adjustment platform 20 and the collimator and accessories 21, and the collimator accessories 21 are selected from the identification rate board.

4.5) Adjust the collimator and the four-degree-of-freedom optical adjustment platform 20, make the optical axis of the zoom lens 22 coincide with the optical axis of the collimator, adjust the imaging assembly 18 and the four-degree-of-freedom optical adjustment platform 20, and align the optical axis of the imaging assembly 18 with the optical axis of the collimator. The zoom lens 22 and the optical axis of the collimator are coaxial, and then the four-degree-of-freedom optical adjustment platform 20, the collimator and accessories 21, the imaging assembly 18, the imaging assembly mounting bracket 12 and the system support bracket 1 are fixed, and the zoom lens automatically faces the image surface. The installation of the optical axis runout detection system is completed.

As shown in Figure 6, the automatic image plane connection of the above-installed zoom lens and the optical axis jump detection system are used for automatic image plane connection, and the method is as follows:

1. The automatic image plane connection of the zoom lens and the optical axis jump detection system are powered on and initialized.

1.1) The automatic image plane connection of the zoom lens and the optical axis jump detection system are powered on, and the collimator selects the discrimination rate target to judge the clarity of the image.

1.2) The automatic image plane connection of the zoom lens and the optical axis jump detection system self-check to determine whether there is any abnormality.

If there is an abnormality in the automatic image plane connection of the zoom lens and the optical axis jump detection system, the software of the upper computer reports a fault, the system stops working, and the corresponding maintenance and processing are carried out.

If the automatic image plane connection of the zoom lens and the self-check of the optical axis jump detection system are normal, then initialize and go to step 2).

2. Determine whether the flange surface of the zoom lens 22 and the flange surface of the imaging assembly 18 are flat without protrusions.

2.1) If there is a bulge between the flange surface of the zoom lens 22 and the flange surface of the imaging assembly 18, install a gasket with a thickness of d between the zoom lens 22 and the flange of the imaging assembly 18 to avoid bumps. After selecting the initialization method, Perform step 2.2).

If the flange surface of the zoom lens 22 and the flange surface of the imaging assembly 18 are flat and have no protrusions, at this time d=0, and perform step 2.2).

2.2) The drive and feedback assembly runs until the flange of the zoom lens 22 is in contact with the flange of the imaging assembly 18, and the upper computer software records the angular displacement information D1 of the potentiometer 2 at this time; at this time, the running direction of the drive and feedback assembly is the positive direction.

3. Determine whether the zoom lens 22 has the clearest position in the short focus

3.1) The zoom lens 22 is switched to the short-focus state, and the initial position of the focusing component on the zoom lens 22 is the theoretical design position of the zoom lens 22. At this time, one-key focus is selected, and the one-key focus command is completed on the host computer.

3.2) The drive and feedback assembly drives the zoom lens 22 to move to the raised limit screw 24 in the opposite direction. During the movement of the zoom lens 22, the image information is uploaded to the display and the host computer software in real time, and the host computer software calculates and compares the grayscale of the images. degree variance and.

3.3) It is judged whether there is a maximum value of the sum of the gray-scale variance values during the movement, and the maximum value of the sum of the gray-scale variance values is not located at the position of the limit screw 24 of the mechanical limit.

If the maximum value of the gray-scale variance value is at the mechanical limit position, it exceeds the working range of the system; at this time, the system is powered off, and the mechanical limit function of the raised limit screw 24 in step 3.2) is cancelled, and the other The limit screw 24 is changed to a raised state, and after the mechanical limit is achieved, step 1 is performed.

If there is a maximum value of the sum of the grayscale variance values, and the maximum value of the sum of the grayscale variance values is not located at the mechanical limit position.

a) The host computer software determines that the zoom lens 22 has the clearest short focus position, and the drive and feedback components drive the zoom lens 22 to run to this position.

b) Manually check whether the image is clear

If it is clear, output the image plane position information D2 at this time.

If it is not clear, manually adjust the drive and feedback components by manual focusing + and focusing - until the zoom lens 22 moves to the clearest position, and then output the image plane position information D2 at this time.

4. Determine whether the zoom lens 22 has the clearest position at the telephoto position.

4.1) Drive the zoom lens 22 to switch to the telephoto position.

4.2) Manually determine whether the telephoto of the zoom lens 22 is the clearest position.

If the telephoto position of the zoom lens 22 is not the clearest position, adjust the focus of the zoom lens 22 focusing assembly through one-key focus to the clearest position, and then jump to step 3.1). Generally, after 3 iterations, the long and short focus can be determined at the same time with the clearest position information.

If the telephoto of the zoom lens 22 is the clearest position, the image plane position information D2 at this time is output, and the actual thickness of the trimming pad on the image plane of the zoom lens 22 is D2-D1+d. are in the clearest position, the image plane is completed.

The algorithm principle of the above one-key focusing is as follows:

During the one-key focusing process, the image is usually seen from blurred to clear, gradually forming a relatively high-definition image. When it is fully focused, the image is the clearest, and the high-frequency components in the image are also the most, and the difference between the gray value of the mutation pixel and the adjacent pixel will also become larger. The grayscale values are subtracted and then multiplied, and then accumulated pixel by pixel to calculate the square of the difference between the grayscale values of two adjacent pixels, as follows:

D(f)=∑ _y ∑ _x |f(x+2,y)-f(x,y)| ²

Among them: f(x, y) represents the gray value of the pixel (x, y) corresponding to the image f, and D(f) refers to the image clarity.

Through this system, the parameters of the zoom lens boresight can also be measured. The specific steps are as follows:

1. The collimator attachment 21 uses a crosshair target to accurately measure the runout.

2. Adjust the optical axis of the collimator through two four-degree-of-freedom optical adjustment platforms 20, and the zoom lens 22 is coaxial with its long and short focal lengths.

3. Set the positions of the drive and feedback components according to the result of the image plane connection. At this time, both the long and short focal positions of the zoom lens 22 can image clearly.

4. The zoom lens 22 is switched to the telephoto state, and the reticle at the center of the target surface of the imaging assembly is coincident with the optical axis of the telephoto state through the four-degree-of-freedom optical platform 20 .

5. Record the position of the optical axis of the zoom lens 22 at this time through the image processing algorithm of the host computer software, and this position is the initial position.

6. Slowly drive the zoom lens 22 to switch from the long focus to the short focus state. The host computer software records the optical axis position of each focal length during the switching process, and identifies the optical axis points calibrated on the image frame by frame and the imaging component target surface at different focal lengths. The difference between the central reticle (Δx, Δy), where Δx is the lateral difference between the optical axis point and the central reticle on the target surface of the imaging assembly, and Δy is the difference between the optical axis point and the central reticle on the target surface of the imaging assembly The longitudinal difference of the zoom lens can be obtained to obtain the optical axis jump parameter of the zoom lens switching from the telephoto end to the short focal end.

7. Using the same method as step 6, measure the optical axis runout parameter of the zoom lens 22 when it switches from the short focal end to the long focal end. At this time, the automatic optical axis jump detection of the zoom lens 22 is completed.

Due to the movement gap between the linear guide 15 and the moving slider 16, the existence of the gap causes the zoom lens 22 to change its posture when it moves back and forth along the optical axis, which will affect the imaging of the imaging assembly 18. uniformity, thus affecting the stability of the system. It is necessary to detect the attitude information during the movement of the lens. As shown in Figure 5, in the above installation process, after the drive and feedback assembly, the guide assembly and the control box 23 are installed (that is, after the installation step 4.1), the stability of the system is detected. The specific detection method is as follows:

1. Fix the system support bracket 1 on the optical platform, and paste a flat reflector 30 near the position where the zoom lens 22 is installed on the lens mounting bracket 14, and adjust the lens mounting bracket 14 to the limit closest to the installation position of the imaging assembly 18. At screw 24, record the position as S at this time.

2. The self-collimation theodolite 29 is placed on the front end of the plane mirror 30, and the self-collimation theodolite 29 is adjusted to make the crosshair coincide with its self-collimating image, and the pitch angle θ and azimuth angle σ of the theodolite are recorded at this time;

3. The drive and feedback components are powered on and run, fine-tune the theodolite pitch angle and azimuth angle so that the autocollimation image coincides with the reticle differentiation line inside the theodolite, and record the movement amount L ₁ of the lens mounting bracket 14 at this time, the theodolite pitch angle θ ₁ and Azimuth σ ₁ ;

Calculate Δθ=θ ₁ -θ, Δσ=σ ₁ -σ;

4. Repeat step 3 until the zoom lens 22 moves to the limit position;

According to the above test data, combined with the zoom lens 22 and the imaging assembly 18 with different focal lengths and pixel sizes, determine whether the running stability meets the requirements;

If the requirements are not met, the guide assembly can choose a higher-precision linear guide 15, or increase the length of the moving slider 16 on the linear guide 15 to reduce the pose change caused by the movement gap; then go to step 2.

If the requirements are met, the automatic image plane connection of the zoom lens and the smoothness detection of the optical axis runout detection system are completed.

If the collimator in the automatic image plane contact and optical axis jump detection method of the zoom lens is a black body, it can be applied to the image plane contact and optical axis jump detection process of the infrared optical lens.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection of the present invention. within the range.

Claims (6)

1. a zoom lens automatic image plane contact and optical axis beat detection method, it is characterized in that: It is realized based on the automatic image plane contact and optical axis jump detection system of the zoom lens, and the automatic image plane contact and optical axis jump detection system of the zoom lens includes a system support bracket (1), a drive and feedback component, a guide component, and an optical imaging component. and control components; The drive and feedback assembly is arranged on the system support bracket (1), and includes a potentiometer (2), a motor (3), a potentiometer gear (4), a motor gear (5), a transmission screw gear (6), a coupling Shaft (7), ball screw nut (8) and nut fixing bracket (9); The input of the potentiometer (2) is connected to the potentiometer gear (4); the output of the motor (3) is connected to the motor gear (5) for driving the motor gear (5) to rotate; the motor gear (5) is connected to the motor gear (5). The drive screw gear (6) is meshed for driving the drive screw gear (6); the drive screw gear (6) is meshed with the potentiometer gear (4) for driving the potentiometer gear (4); The transmission screw gear (6) is connected with the ball screw nut (8) through the coupling (7), so as to realize the movement of the ball screw nut (8), and the ball screw nut (8) is fixedly connected to the bracket (8) through the nut. 9) connecting with the zoom lens mounting bracket (14) to realize the movement of the zoom lens mounting bracket (14); The guide assembly includes two linear guide rails (15), two moving sliders (16) and a zoom lens mounting bracket (14); the two linear guide rails (15) are installed on the system support bracket (1) in parallel, and the straight A limit screw (24) is provided on the guide rail (15), and the limit screw (24) is used to limit the displacement of the zoom lens mounting bracket (14); the moving slider (16) is arranged on the linear guide rail (15), The moving slider (16) is fixedly connected with the zoom lens mounting bracket (14); The optical imaging assembly includes an imaging assembly (18), an imaging assembly mounting bracket (19), two four-degree-of-freedom optical adjustment platforms (20), a collimator and accessories (21), and a zoom lens (22); The imaging assembly (18) is installed on the four-degree-of-freedom optical adjustment platform (20) through the imaging-assembly mounting bracket (19), and the collimator and accessories (21) are installed on the other four-degree-of-freedom optical adjustment platform (20). On a plane, the four-degree-of-freedom optical adjustment platform (20) is mounted on the system support bracket (1); the zoom lens (22) is mounted on the zoom-lens mounting bracket (14); the four-degree-of-freedom optical adjustment platform (20) ) is used to adjust the optical axis of the collimator, the zoom lens (22) and the imaging assembly (18) to be coaxial; The control assembly includes a control box (23), a host computer and a video display; the host computer is installed with host computer software; the control box (23), a potentiometer (2), a motor (3), and a zoom lens (22) It is connected with the host computer to record the angular displacement information of the potentiometer (2), the telephoto or short focus state of the zoom lens (22), control the work of the motor (3), and transmit the information to the host computer; the video display is connected to the The host computer is connected with the imaging component (18), so as to display the image information of the imaging component (18) at different positions; The drive and feedback assembly further comprises a front screw fixing bracket (10), a rear screw fixing bracket (11) and an assembly mounting bracket (12); The front end of the coupling (7) is mounted on the front fixing bracket (10) of the lead screw through an angular contact bearing (13), and the rear end is connected with the lead screw of the ball screw nut (8), and the ball screw nut The other end of the screw rod of (8) is mounted on the rear screw rod fixing bracket (11) through an angular contact bearing (13), and the front screw rod fixing bracket (10) is fixedly connected to the screw rod rear fixing bracket (11); The potentiometer (2), the motor (3) and the front fixing bracket (10) of the screw rod are all mounted on the component mounting bracket (12), and the component mounting bracket (12) is fixed on the system support bracket (1); The specific steps are as follows: Step 1: Install the automatic image plane connection and optical axis jump detection system of the zoom lens Step 2: Automatic image plane connection of zoom lens 1) The automatic image plane connection of the zoom lens and the optical axis beat detection system are powered on, and the collimator selects the discrimination rate target and initializes it; 2) Judging whether the flange surface of the zoom lens (22) and the flange surface of the imaging assembly (18) are flat without protrusions; 2.1) If there is a bulge between the flange surface of the zoom lens (22) and the flange surface of the imaging assembly (18), install a gasket of thickness d between the zoom lens (22) and the flange of the imaging assembly (18) to avoid the bulge. Collision, and initialization, and then perform step 2.2); If the flange surface of the zoom lens (22) and the flange surface of the imaging assembly are flat and no protrusions, at this time d=0, go to step 2.2); 2.2) The drive and feedback assembly runs until the flange of the zoom lens (22) is in contact with the flange of the imaging assembly (18), and the upper computer software records the angular displacement information D1 of the potentiometer (2) at this time; at this time, the drive and feedback assembly runs The direction is the positive direction; 3) judging whether the zoom lens (22) has the clearest position in the short focus; 3.1) The zoom lens (22) is switched to the short-focus state, and the initial position of the focusing assembly on the zoom lens (22) is the theoretical design position of the zoom lens (22). At this time, one-key focusing is selected; the one-key focusing instruction is in Completed on the host computer; 3.2) The drive and feedback assembly drives the zoom lens (22) to move in the opposite direction to the raised limit screw (24). During the movement of the zoom lens (22), the image information is uploaded to the display and the host computer software in real time. Computer software calculates and compares the sum of the grayscale variance of the images; 3.3) Judging whether there is a maximum value of the sum of the gray-scale variance values during the movement, and the maximum value of the sum of the gray-scale variance values is not located at the position of the limit screw (24) of the mechanical limit; If the maximum value of the gray-scale variance value is at the mechanical limit position, it is beyond the working range of the system; at this time, the system is powered off, and the mechanical limit function of the raised limit screw (24) in step 3.2) is cancelled, and the The other limit screw (24) is changed to a raised state, and after the mechanical limit is achieved, perform step 1); If there is a maximum value of the sum of the grayscale variance values, and the maximum value of the sum of the grayscale variance values is not located at the mechanical limit position; a) The host computer software determines that the zoom lens (22) has the clearest short focus position, and the drive and feedback assembly drives the zoom lens (22) to run to this position; b) Check whether the image is clear; If it is clear, output the image plane position information D2 at this time; If it is not clear, manually adjust the drive and feedback components by means of manual focusing + and focusing - until the zoom lens (22) moves to the clearest position, and then output the image plane position information D2 at this time; 4) judging whether the zoom lens (22) has the clearest position at the telephoto position; 4.1) Drive the zoom lens (22) to switch to the telephoto position; 4.2) Determine whether the telephoto of the zoom lens (22) is the clearest position; If the telephoto position of the zoom lens (22) is not the clearest position, adjust the focus of the zoom lens (22) focusing assembly by one-key focusing to the clearest position, and then jump to step 3.1); If the telephoto of the zoom lens (22) is the clearest position, the image surface position information D2 at this time is output, and the actual thickness of the trimming pad on the image surface of the zoom lens (22) is D2-D1+d; at this time, the zoom lens (22) If both the telephoto and short focal points are in the clearest position, the image plane is connected; Step 3: Automatic Optical Axis Runout Detection of the Zoom Lens (22) 1) The collimator uses a crosshair target to accurately measure the runout; 2) Adjust the optical axis of the collimator through the four-degree-of-freedom optical adjustment platform (20), and the zoom lens (22) is coaxial with its long and short focal lengths; 3) According to the result of the image plane contact, the positions of the drive and feedback components are set, and at this time, the zoom lens (22) can be clearly imaged at both the long and short focal positions; 4) The zoom lens (22) is switched to the telephoto state, and the center reticle on the target surface of the imaging assembly is coincident with the optical axis of the telephoto state through the four-degree-of-freedom optical platform (20); 5) Record the position of the optical axis of the zoom lens (22) at this time through the image processing algorithm of the host computer software, and this position is the initial position; 6) Slowly drive the zoom lens (22) to switch from the long focus to the short focus state, the host computer software records the optical axis position of each focal length during the switching process, and identifies the optical axis points calibrated on the image frame by frame and the imaging components at different focal lengths. The difference Δx and Δy between the reticle at the center of the target surface, so as to obtain the optical axis runout parameter of the zoom lens switching from the long focal end to the short focal end; the Δx is the difference between the optical axis point and the center reticle on the target surface of the imaging component The lateral difference between Δy is the longitudinal difference between the optical axis point and the reticle in the center of the target surface of the imaging assembly; 7) Use the same method as step 6) to measure the optical axis jump parameter of the zoom lens (22) switching from the short focal end to the telephoto end; at this time, the automatic optical axis jump detection of the zoom lens (22) is completed. 2. The automatic image plane contact and optical axis jump detection method of a zoom lens according to claim 1, wherein the parallel light pipe is a black body, which is suitable for the image plane contact and optical axis of an infrared optical lens Bounce detection process. 3. a kind of zoom lens automatic image plane contact and optical axis jump detection method according to claim 1 and 2, is characterized in that, step 1 also comprises to zoom lens automatic image plane contact and optical axis jump detection system operation The specific steps for the detection of stationarity are as follows: 1) Install the drive and feedback assembly, guide assembly and control box (23); 2) Detect the running stability of the automatic image plane connection of the zoom lens and the optical axis jump detection system; 2.1) Fix the system support bracket (1) on the optical table, and paste a flat reflector (30) near the position where the zoom lens mounting bracket (14) is installed with the zoom lens (22); Adjust the zoom lens mounting bracket (14) to the limit screw (24) closest to the mounting position of the imaging assembly (18), and record the current position as S; 2.2) Place the auto-collimation theodolite (29) on the front of the plane mirror (30), and adjust the auto-collimation theodolite (29) to make the crosshairs coincide with the auto-collimation image, and record the elevation angle θ and azimuth angle σ of the theodolite at this time. ; 2.3) The drive and feedback components are powered on and run, fine-tune the theodolite pitch angle and azimuth angle so that the autocollimation image coincides with the reticle differentiation line inside the theodolite, and record the movement amount L ₁ of the zoom lens mounting bracket (14) and the theodolite pitch angle at this time. θ ₁ and azimuth angle σ ₁ ; Calculate Δθ=θ ₁ -θ, Δσ=σ ₁ -σ; 2.4) Repeat step 2.3) until the zoom lens (22) moves to the limit position; According to the test data and in combination with the zoom lens (22) and the imaging component (18) with different focal lengths and pixel sizes, it is judged whether the running stability meets the requirements; If the requirements are not met, a higher-precision linear guide (15) can be selected for the guide assembly, or the length of the moving slider (16) on the linear guide (15) can be increased to reduce the pose change caused by the movement gap; step 2); If the requirements are met, the automatic image plane connection of the zoom lens and the smoothness detection of the optical axis runout detection system are completed; 3) Install the remaining components. 4. The method for detecting automatic image plane contact and optical axis jump of a zoom lens according to claim 1, wherein a trimming pad is installed at the junction of the component mounting bracket (12) and the system support bracket (1), Used to adjust the attitude of the drive and feedback components. 5. A zoom lens automatic image plane contact and optical axis jump detection method according to any one of claims 1 and 4, characterized in that: the potentiometer gear (4) and the transmission screw gear (6) adopt Double gear meshing mode transmission, the transmission backlash is less than 0.18°, and the feedback error is less than 5.4°; The potentiometer gear (4) includes a first potentiometer gear (41) and a second potentiometer gear (42) that mesh with the transmission screw gear (6) at the same time; the first potentiometer gear (41) and the second potentiometer gear (41) The meter gear (42) is coaxially installed, and the gear teeth of the first potentiometer gear (41) and the second potentiometer gear (42) are interleaved in the circumferential direction. 6. A zoom lens automatic image plane contact and optical axis jump detection method according to claim 5, characterized in that: the transmission ratio of the drive screw gear (6) and the potentiometer gear (4) is 3.4375, The number of gears of the drive screw gear (6) is 110, the number of gears of the first potentiometer gear (41) and the second potentiometer gear (42) are both 32, and the modulus is 0.25.

Images