Device and method for measuring optical transfer function of TDI optical imaging camera

Abstract

The invention discloses a device and a method for measuring an optical transfer function of a TDI optical imaging camera, and solves the problem that in the measurement of dynamic transfer function parameters of an existing optical imaging camera, a test condition close to a real on-orbit environment cannot be realized, so that the rapid and high-precision measurement of a dynamic modulation transfer function cannot be realized. The device comprises a sealing cavity formed by an experiment module and a base, a six-degree-of-freedom adjusting mechanism, an experiment module sealing mechanism, a first air floating platform, a second air floating platform, a collimator, an experiment module window, a focal plane mechanism and a control system, wherein the six-degree-of-freedom adjusting mechanism, the experiment module sealing mechanism, the first air floating platform, the second air floating platform, the collimator and the experiment module window are arranged in the sealing cavity; an on-orbit environment is simulated through the experiment module, an air floating translation platform in the focal plane mechanism drives a target to realize simulation of a dynamic target, dynamic optical transfer function measurement of the optical imaging camera in the on-orbit environment can be realized, the imaging performance of the TDI optical imaging camera in the on-orbit state can be accurately reflected, and system installation and detection can be accurately guided.

Description

Technical Field

[0001] This invention relates to a dynamic optical transfer function measurement device and method, specifically to an optical transfer function measurement device and method for a TDI optical imaging camera. Background Technology

[0002] Optoelectronic imaging systems, as core sensing and measurement tools in modern information equipment, play an irreplaceable role in target detection, identification, and tracking, and are particularly widely used in high-precision imaging fields such as aerospace and remote sensing. The optical transfer function (OTF), a key indicator for evaluating the imaging quality of an optoelectronic imaging system, is used throughout the entire process of optical system design, fabrication, assembly, testing, and overall performance evaluation. Among these, the modulation transfer function (MTF) quantitatively characterizes the system's ability to transmit signals at different spatial frequencies and is a core parameter for measuring imaging resolution and contrast.

[0003] For optoelectronic imaging systems with image shift compensation (such as Time-Delay Integration (TDI) cameras), they are often in a dynamic imaging state in actual working environments. Therefore, static MTF testing cannot fully reflect the system's true performance. Dynamic Modulation Transfer Function (DMTF) testing technology, by simulating the imaging process under motion conditions, can more accurately evaluate the system's imaging quality in dynamic scenes, providing an important basis for system optimization and performance verification.

[0004] On-orbit imaging quality assessment is a key step in the development and verification of TDI cameras. Currently, the testing methods for the dynamic imaging performance of TDI cameras are mainly divided into two categories: (1) Dynamic target method: by controlling the movement of the target, the image sequence of the moving target is acquired using a static imaging system, and then the DMTF is calculated; (2) Dynamic imaging system method: when the imaging system is in motion, the static or dynamic target is imaged, and the DMTF is obtained by analyzing the image data.

[0005] Among them, the dynamic target method has become the preferred solution in the ground test environment due to its simple test equipment structure, low cost, and ease of achieving high-precision motion control. However, the existing dynamic target test devices still have the following limitations: (1) Insufficient environmental simulation: It is difficult to reproduce the impact of complex on-orbit conditions (such as high and low brightness targets, vacuum and low pressure, temperature changes, etc.) on imaging performance; (2) Low test efficiency: Traditional methods require multiple adjustments to target and system parameters, which takes a long time; (3) Limited accuracy: Insufficient coordination between motion control and image analysis leads to deviations in DMTF calculation results. Summary of the Invention

[0006] The purpose of this invention is to solve the problem that existing measurements of the dynamic transfer function parameters of optical imaging cameras cannot achieve test conditions close to the real on-orbit environment, thus failing to achieve fast and high-precision measurement of the dynamic modulation transfer function. The invention provides an optical transfer function measurement device and method for TDI optical imaging cameras.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An optical transfer function measurement device for a TDI optical imaging camera includes a sealed cavity formed by an experimental chamber simulating an environment and a base. The device is characterized by further including a six-degree-of-freedom adjustment mechanism, an experimental chamber sealing mechanism, a first air-bearing platform, a second air-bearing platform, a collimator, an experimental chamber window set on the side wall of the sealed cavity, and a focal plane mechanism and a control system connected to the base and located outside the experimental chamber.

[0009] The first air-floating platform and the second air-floating platform are respectively set on the base through the experimental chamber sealing mechanism. The first air-floating platform is connected to a six-degree-of-freedom adjustment mechanism. The working end of the six-degree-of-freedom adjustment mechanism is used to connect to the TDI optical imaging camera. The second air-floating platform is connected to a collimator. The output end of the collimator is opposite to the input end of the TDI optical imaging camera, and the output port diameter of the collimator is larger than the effective receiving port diameter of the input end of the TDI optical imaging camera.

[0010] The input end of the collimator is connected to the experimental chamber window, the focal plane of the collimator is located outside the experimental chamber window, the experimental chamber window is sealed to the side wall of the experimental chamber, and the experimental chamber window is used for beam transmission.

[0011] The output end of the focal plane mechanism is opposite to the experimental chamber window. The focal plane mechanism is used to output simulated static and dynamic targets in various states at the focal plane of the collimator.

[0012] The control system is electrically connected to the six-degree-of-freedom adjustment mechanism, the first air flotation platform, the second air flotation platform, and the coke surface mechanism.

[0013] Furthermore, the focal plane mechanism includes a one-dimensional translation stage a, a one-dimensional air-bearing translation stage, a one-dimensional translation stage b, a conventional target mechanism, a push-broom target mechanism, a blackbody light source, and an integrating sphere light source;

[0014] The light emission axes of the blackbody light source and the integrating sphere light source are parallel to each other, and their bottoms are both connected to the working end of the one-dimensional translation stage a. The moving direction of the working end of the one-dimensional translation stage a is parallel to the moving direction of the working end of the one-dimensional translation stage a.

[0015] The conventional target mechanism and the push-broom target mechanism are both connected to the working end of a one-dimensional air-floating translation stage at their bottom. The moving direction of the working end of the one-dimensional air-floating translation stage is perpendicular to the light emission axis of the blackbody light source and the integrating sphere light source.

[0016] The bottom of the one-dimensional translation stage a and the one-dimensional air-floating translation stage are both connected to the working end of the one-dimensional translation stage b. The one-dimensional air-floating translation stage is set close to the experimental chamber window. The moving direction of the working end of the one-dimensional translation stage b is parallel to the light emission axis of the blackbody light source and the integrating sphere light source, which is used to drive the conventional target mechanism or the push-broom target mechanism to move closer to or away from the experimental chamber window.

[0017] The one-dimensional translation stage b is connected to the base via a support frame;

[0018] The control terminals of the one-dimensional translation stage a, the one-dimensional air-floating translation stage, and the one-dimensional translation stage b are all connected to the control system, which controls the movement of the working ends of the one-dimensional translation stage a, the one-dimensional air-floating translation stage, and the one-dimensional translation stage b.

[0019] The control system is electrically connected to the push-broom target mechanism, the blackbody light source, and the integrating sphere light source.

[0020] Furthermore, the focal plane mechanism also includes a housing;

[0021] The bottom of the outer shell is connected to a support frame, and the one-dimensional translation stage a, one-dimensional air-floating translation stage, one-dimensional translation stage b, conventional target mechanism, push-broom target mechanism, blackbody light source, and integrating sphere light source are all housed inside the outer shell.

[0022] Furthermore, the conventional target mechanism is used to install conventional targets, which include a star-shaped target plate, a resolution plate, and a reticle plate;

[0023] The push-broom target mechanism includes a rotating structure for mounting a specific push-broom stripe plate target and enabling the target to spin.

[0024] A method for measuring the optical transfer function of a TDI optical imaging camera, characterized in that it uses the aforementioned optical transfer function measurement device for a TDI optical imaging camera, and includes the following steps:

[0025] Step 1: Fix the bottom of the experimental chamber to the optical platform, connect the TDI optical imaging camera to the working end of the six-degree-of-freedom adjustment mechanism, and adjust the optical axis of the TDI optical imaging camera to be roughly aligned with the central axis of the collimator through the six-degree-of-freedom adjustment mechanism.

[0026] Step 2: Adjust the focal plane mechanism to output a simulated static target at the focal plane position of the collimator, and then project it through the experimental chamber window and collimator to the input end of the TDI optical imaging camera. Adjust the six-degree-of-freedom adjustment mechanism to align the optical axis of the TDI optical imaging camera with the central axis of the collimator, and record the working end position of the six-degree-of-freedom adjustment mechanism as zero.

[0027] Step 3: Adjust the focal plane mechanism output to simulate a static target according to the TDI array direction of the TDI optical imaging camera, set up the experimental chamber simulation environment, adjust the straightness of the TDI detector of the TDI optical imaging camera and test the static optical transfer function to obtain the static optical transfer function parameters.

[0028] Step 4: According to the scanning frequency requirements of the TDI optical imaging camera, adjust the output of the focal plane mechanism to simulate the dynamic target, set up the simulation environment in the experimental chamber, and perform dynamic optical transfer function test on the TDI optical imaging camera to obtain the dynamic optical transfer function.

[0029] Step 5: Adjust the azimuth and pitch attitude of the working end of the six-degree-of-freedom adjustment mechanism through the control system, and repeat steps 3 and 4 to obtain the static optical transfer function parameters and dynamic optical transfer function under this attitude.

[0030] Furthermore, step 2 specifically involves:

[0031] Step 2.1: Control the working end of the one-dimensional air-floating translation stage through the control system to move the conventional target mechanism to the focal plane position of the collimator, and move the working end of the one-dimensional translation stage a to make the blackbody light source or integrating sphere light source face the conventional target mechanism. Simulate the light source through the blackbody light source or integrating sphere light source, and emit simulated static target through the conventional target mechanism.

[0032] Step 2.2: The simulated static target enters the experimental chamber through the experimental chamber window, exits as a parallel beam through the collimator, and is incident on the TDI detector target surface of the TDI optical imaging camera.

[0033] Step 2.3: Activate the six-degree-of-freedom adjustment mechanism, the first air-bearing platform, and the second air-bearing platform. Adjust the azimuth and pitch attitude of the six-degree-of-freedom adjustment mechanism to align the optical axis of the TDI optical imaging camera with the central axis of the collimator. Record the working end position parameters of the six-degree-of-freedom adjustment mechanism as the zero position.

[0034] Furthermore, step 3 specifically involves:

[0035] A one-dimensional air-floating translation stage is used to move the pushbroom target mechanism to the center of the focal plane of the collimator. Based on the TDI array line direction of the TDI optical imaging camera, the pushbroom target mechanism is rotated so that the direction of the scribing lines on the striped target of the pushbroom target mechanism is consistent with the direction of the integral series of the TDI detector of the TDI optical imaging camera. The experimental chamber simulation environment is set up, and images are acquired through the input end of the TDI optical imaging camera. The static optical transfer function parameters are tested based on the acquired images, and the straightness of the TDI detector of the TDI optical imaging camera is adjusted at the same time.

[0036] Furthermore, the rotating push-broom target mechanism, specifically aligning the direction of the scribed lines on the striped target with the direction of the integration series of the TDI detector in the TDI optical imaging camera, is as follows:

[0037] Adjust the spin of the target on the push-broom target mechanism and observe the stripe image acquired by the TDI optical imaging camera. When the contrast of the acquired stripe image is the highest, the direction of the scribing line on the stripe plate target of the push-broom target mechanism is consistent with the direction of the integration series of the TDI detector of the TDI optical imaging camera.

[0038] Furthermore, step 4 specifically involves:

[0039] Step 4.1: Rotate the striped target of the push-broom target mechanism by 90 degrees, and set the motion frequency of the one-dimensional air-floating translation stage according to the scanning frequency requirements of the TDI detector of the TDI optical imaging camera.

[0040] Step 4.2: Control the one-dimensional air-bearing translation stage through the control system to drive the push-broom target mechanism to move, thereby simulating the dynamic target in the dynamic optical transfer function test;

[0041] Step 4.3: Set up a simulated environment for the experimental chamber, acquire dynamic target images of the simulated focal plane position of the collimator using a TDI optical imaging camera, and obtain the dynamic optical transfer function based on the dynamic target images.

[0042] Furthermore, the formulas for calculating the static optical transfer function parameters and the dynamic optical transfer function are as follows:

[0043]

[0044] In the formula, MTF represents the static optical transfer function parameter or the dynamic optical transfer function, and DN... w This indicates reading the grayscale output value corresponding to the white stripes in the image, DN. b DN represents the grayscale output value corresponding to the black stripes in the image. B This represents the background grayscale output value.

[0045] The beneficial effects of this invention are:

[0046] (1) This invention provides an optical transfer function measurement device and method for a TDI optical imaging camera. The experimental chamber can simulate on-orbit environments such as vacuum and high and low temperature environments. The air-floating translation stage in the focal plane mechanism can drive the target to simulate dynamic targets. Furthermore, it can realize the dynamic optical transfer function measurement of the optical imaging camera in the on-orbit environment, which can accurately reflect the imaging performance of the TDI optical imaging camera in the on-orbit state and accurately guide the system assembly, adjustment and testing.

[0047] (2) The present invention provides an optical transfer function measurement device and measurement method for a TDI optical imaging camera, wherein the first air-floating platform for placing the test product and the second air-floating platform for the test equipment are respectively connected to the base, which can avoid the influence of the test chamber on the test data when it is in operation; the first air-floating platform and the second air-floating platform are independent of each other, reducing the influence of the test product parameter test of the test equipment; by using the air-floating platform, the influence of external environmental factors such as vibration on the test results can be further reduced. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of an embodiment of an optical transfer function measurement device for a TDI optical imaging camera provided by the present invention;

[0049] Figure 2 This invention provides a schematic diagram of the internal structure of the focal plane mechanism in an embodiment of an optical transfer function measurement device for a TDI optical imaging camera.

[0050] Figure 3 This invention provides a schematic diagram of the relationship between the TDI detector and the stripe plate attitude during static optical transfer function parameter testing of a TDI optical imaging camera (2) in an embodiment of the optical transfer function measurement method for a TDI optical imaging camera.

[0051] Figure 4 This invention provides a method for measuring the optical transfer function of a TDI optical imaging camera. The diagram shows the relationship between the TDI detector and the stripe plate attitude when the dynamic optical transfer function is measured.

[0052] 1-Experimental chamber; 2-TDI optical imaging camera; 3-Six-degree-of-freedom adjustment mechanism; 4-Experimental chamber sealing mechanism; 5-First air-bearing platform; 6-Second air-bearing platform; 7-Parallel light tube; 8-Experimental chamber window; 9-Focal plane mechanism; 901-One-dimensional translation stage a; 902-One-dimensional air-bearing translation stage; 903-One-dimensional translation stage b; 904-Conventional target mechanism; 905-Push-broom target mechanism; 906-Blackbody light source; 907-Integrating sphere light source; 10-Control system; 11-Base. Detailed Implementation

[0053] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0054] This embodiment provides an optical transfer function measurement device for a TDI optical imaging camera, such as... Figure 1 As shown, the system includes a sealed cavity formed by the experimental chamber 1 and the base 11, a six-degree-of-freedom adjustment mechanism 3 disposed within the sealed cavity, an experimental chamber sealing mechanism 4, a first air-float platform 5, a second air-float platform 6, a collimator 7, an experimental chamber window 8, a focal plane mechanism 9 connected to the base 11 and located outside the experimental chamber 1, and a control system 10. Inside the sealed cavity, the first air-float platform 5 and the second air-float platform 6 are connected to the base 11 via the experimental chamber sealing mechanism 4. The six-degree-of-freedom adjustment mechanism 3 is connected to the first air-float platform 5, and its working end is used to connect to the TDI optical imaging camera 2. The collimator 7 is connected to the second air-float platform 6, and the output end of the collimator 7 is opposite to the input end of the TDI optical imaging camera 2, with the output port diameter of the collimator 7 being larger than the effective receiving aperture of the input end of the TDI optical imaging camera 2. The input end of the collimator 7 is connected to the experimental chamber window 8. The focal plane of the collimator 7 is located outside the sealed cavity. The experimental chamber window 8 is sealed to the side wall of the experimental chamber 1 and is used for beam transmission. The output end of the focal plane mechanism 9 is opposite to the experimental chamber window 8 and is used to output simulated static and dynamic targets in various states. The control system 10 is electrically connected to the experimental chamber 1, the six-degree-of-freedom adjustment mechanism 3, the first air-bearing platform 5, the second air-bearing platform 6, and the focal plane mechanism 9.

[0055] Among them, Experiment Module 1 is used to simulate experimental environments such as on-orbit vacuum, low pressure, and high and low temperatures.

[0056] The six-degree-of-freedom adjustment mechanism 3 can achieve adjustment in six degrees of freedom, specifically translation in the X, Y, and Z axes and rotation around the X, Y, and Z axes; the TDI optical imaging camera 2 is placed on top of it, indirectly realizing the attitude adjustment of the TDI optical imaging camera 2.

[0057] The experimental chamber sealing mechanism 4 is used to flexibly seal the first air flotation platform 5, the second air flotation platform 6 and the base 11, ensuring that the first air flotation platform 5, the second air flotation platform 6, the experimental chamber 1 and the base 11 are connected separately and do not interfere with each other.

[0058] The first air-floating platform 5 is directly connected to the base 11 and is separated from the experimental chamber 1, ensuring that the vibration generated by the experimental chamber 1 during operation will not be transmitted to the first air-floating platform 5; it is used to house the TDI optical imaging camera 2 and the six-degree-of-freedom adjustment mechanism 3.

[0059] The second air flotation platform 6 is directly connected to the base and is separated from the experimental chamber 1, ensuring that the vibration generated by the experimental chamber during operation will not be transmitted to the second air flotation platform 6; it is used to place the parallel light tube 7.

[0060] The collimator 7 is used to emit the parallel beam required for the test; the aperture of the beam emitted from the collimator 7 should be larger than the effective receiving aperture of the TDI optical imaging camera 2.

[0061] Experimental window 8 allows for the transmission of light beams between the experimental chamber 1 and the outside.

[0062] The focal plane mechanism 9 is used for target simulation in different states; it can switch between targets of different shapes, materials and sizes; and it can switch between light sources of different wavelengths and intensities.

[0063] In this embodiment, as Figure 2 As shown, the focal plane mechanism 9 includes a one-dimensional translation stage a901, a one-dimensional air-bearing translation stage 902, a one-dimensional translation stage b903, a conventional target mechanism 904, a push-broom target mechanism 905, a blackbody light source 906, and an integrating sphere light source 907.

[0064] The blackbody light source 906 is used to simulate an infrared light source, and the integrating sphere light source 907 is a broadband uniform light source with adjustable brightness. The emission axes of the blackbody light source 906 and the integrating sphere light source 907 are parallel to each other, and their bottoms are connected to the working end of a one-dimensional translation stage a901. The moving direction of the working end of the one-dimensional translation stage a901 is perpendicular to the emission axes of the blackbody light source 906 and the integrating sphere light source 907. The switching between the blackbody light source 906 and the integrating sphere light source 907 can be achieved by translating the one-dimensional translation stage a901.

[0065] The bottom of both the conventional target mechanism 904 and the push-broom target mechanism 905 is connected to the working end of the one-dimensional air-floating translation stage 902. The working end of the one-dimensional air-floating translation stage 902 moves perpendicular to the light-emitting optical axis of the blackbody light source 906 and the integrating sphere light source 907. The one-dimensional air-floating translation stage 902 can achieve one-dimensional high-speed motion at a predetermined frequency, which can drive the conventional target mechanism 904 and the push-broom target mechanism 905 to simulate dynamic targets.

[0066] The bottom of both the one-dimensional translation stage a901 and the one-dimensional air-floating translation stage 902 are connected to the working end of the one-dimensional translation stage b903. The one-dimensional air-floating translation stage 902 is close to the experimental chamber 8. The working end of the one-dimensional translation stage b903 moves in a direction parallel to the light-emitting optical axis of the blackbody light source 906 and the integrating sphere light source 907. The working end of the one-dimensional translation stage b903 can move along the optical axis, which can realize the front and rear defocusing movement of the light tube and the simulation of the defocusing state.

[0067] The bottom of the one-dimensional translation stage b903 is connected to the base 11 via a support frame. The support frame can support the one-dimensional translation stage b903 and allow the light emitted by the blackbody light source 906 or the integrating sphere light source 907 to enter the experimental chamber window 8 through the conventional target mechanism 904 or the push-broom target mechanism 905.

[0068] The working ends of one-dimensional translation stage a901, one-dimensional air-floating translation stage 902, and one-dimensional translation stage b903 are all connected to the control system 10, and the control system 10 controls the movement of the working ends of one-dimensional translation stage a901, one-dimensional air-floating translation stage 902, and one-dimensional translation stage b903.

[0069] The control system 10 is electrically connected to the push-broom target mechanism 905, the blackbody light source 906, and the integrating sphere light source 907.

[0070] To protect components such as the one-dimensional translation stage a901, one-dimensional air-bearing translation stage 902, one-dimensional translation stage b903, push-broom target mechanism 905, blackbody light source 906, and integrating sphere light source 907, an outer shell is installed, with a support frame connected to the bottom of the shell.

[0071] A method for measuring the optical transfer function of a TDI optical imaging camera, using an optical transfer function measurement device for a TDI optical imaging camera, includes the following steps:

[0072] Step 1: Fix the bottom of the experimental chamber 1 on the optical platform, connect the TDI optical imaging camera 2 to the working end of the six-degree-of-freedom adjustment mechanism 3, and adjust the optical axis of the TDI optical imaging camera 2 to be roughly aligned with the central axis of the collimator 7 through the six-degree-of-freedom adjustment mechanism 3. The collimator 7 completes the calibration in the air-bearing working state of the second air-bearing platform 6.

[0073] Step 2: Adjust the focal plane mechanism 9 to output a simulated static target at the focal plane position of the collimator 7, and incident it onto the input end of the TDI optical imaging camera 2 through the experimental chamber window 8 and the collimator 7. Adjust the six-degree-of-freedom adjustment mechanism 3 to align the optical axis of the TDI optical imaging camera 2 with the central axis of the collimator 7, and record the working end position of the six-degree-of-freedom adjustment mechanism 3 as zero. Specifically:

[0074] Step 2.1: Control the working end of the one-dimensional air-floating translation stage 902 through the control system 10 to move the conventional target mechanism 904 to the focal plane position of the collimator 7, and move the working end of the one-dimensional translation stage a901 so that the blackbody light source 906 or the integrating sphere light source 907 is opposite to the conventional target mechanism 904. The blackbody light source 906 or the integrating sphere light source 907 simulates the light source and emits a simulated static target through the conventional target mechanism 904.

[0075] Step 2.2: The simulated static target enters the experimental chamber 1 through the experimental chamber window 8, and is emitted as a parallel beam by the collimator 7, which is then incident on the TDI detector target surface of the TDI optical imaging camera 2.

[0076] Step 2.3: Activate the six-degree-of-freedom adjustment mechanism 3, the first air-bearing platform 5, and the second air-bearing platform 6. Using the optical axis of the TDI optical imaging camera 2 as the design reference, adjust the azimuth and pitch attitude of the six-degree-of-freedom adjustment mechanism 3 to align the optical axis of the TDI optical imaging camera 2 with the central axis of the collimator 7. Record the working end position parameters of the six-degree-of-freedom adjustment mechanism 3 as the zero position.

[0077] Step 3: Move the one-dimensional air-bearing translation stage 902 to move the push-broom target mechanism 905 to the center of the focal plane of the collimator 7. Based on the TDI array line direction of the TDI optical imaging camera 2, rotate the push-broom target mechanism 905 so that the direction of the scribed lines on the striped target of the push-broom target mechanism 905 is consistent with the direction of the integration series of the TDI detector of the TDI optical imaging camera 2. Specifically: Figure 3 As shown, the spin of the target on the push-broom target mechanism 905 is adjusted, and the stripe image acquired by the TDI optical imaging camera 2 is observed. When the contrast of the acquired stripe image is the highest, the direction of the scribing line on the stripe plate target of the push-broom target mechanism 905 is consistent with the direction of the integration series of the TDI detector of the TDI optical imaging camera 2.

[0078] The experimental chamber 1 was set up to simulate the environment. Images were acquired through the input terminal of the TDI optical imaging camera 2. The static optical transfer function parameters were tested based on the acquired images. At the same time, the straightness of the TDI detector in the TDI optical imaging camera 2 was adjusted.

[0079] Step 4: Based on the scanning frequency requirements of the TDI optical imaging camera 2, adjust the output of the focal plane mechanism 9 to simulate a dynamic target, set up a simulation environment in the experimental chamber 1, and perform a dynamic optical transfer function test on the TDI optical imaging camera 2 to obtain the dynamic optical transfer function; specifically:

[0080] Step 4.1: Rotate the striped target of the push-broom target mechanism 905 by 90 degrees, as follows: Figure 4 As shown, according to the scanning frequency requirements of the TDI detector of the TDI optical imaging camera 2, the motion frequency of the one-dimensional air-floating translation stage 902 is set by the control system 10.

[0081] Step 4.2: Control the one-dimensional air-floating translation stage 902 through the control system 10 to drive the push-broom target mechanism 905 to move, thereby simulating the dynamic target in the dynamic optical transfer function test;

[0082] Step 4.3: Set up a simulated environment for the experimental chamber 1, and acquire a dynamic target image simulating the focal plane position of the collimator 7 using the TDI optical imaging camera 2. Obtain the dynamic optical transfer function based on the dynamic target image.

[0083] Step 5: Adjust the azimuth and pitch attitude of the working end of the six-degree-of-freedom adjustment mechanism 3 through the control system 10, and repeat steps 3 and 4 to obtain the static optical transfer function parameters and dynamic optical transfer function under this attitude.

[0084] In this embodiment, environmental stability needs to be ensured during data acquisition by the TDI optical imaging camera 2, and more than 100 sets of image data should be acquired; the calculation formulas for the static optical transfer function parameters and the dynamic optical transfer function are as follows:

[0085]

[0086] In the formula, MTF represents the static optical transfer function parameter or the dynamic optical transfer function, and DN... w This indicates reading the grayscale output value corresponding to the white stripes in the image, DN. b DN represents the grayscale output value corresponding to the black stripes in the image. B This represents the background grayscale output value.

[0087] The above description is merely a specific embodiment of the present invention and a comparison of the effects of the specific embodiments with relevant comparative examples. However, the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An optical transfer function measurement device for a TDI optical imaging camera, comprising a sealed cavity formed by an experimental chamber (1) simulating an environment and a base (11), characterized in that: It also includes a six-degree-of-freedom adjustment mechanism (3) installed in the sealed cavity, an experimental chamber sealing mechanism (4), a first air-floating platform (5), a second air-floating platform (6), a parallel light tube (7), an experimental chamber window (8) installed on the side wall of the sealed cavity, and a focal plane mechanism (9) connected to the base (11) and located outside the experimental chamber (1) and a control system (10). The first air-floating platform (5) and the second air-floating platform (6) are respectively set on the base (11) through the experimental chamber sealing mechanism (4). The first air-floating platform (5) is connected to a six-degree-of-freedom adjustment mechanism (3). The working end of the six-degree-of-freedom adjustment mechanism (3) is used to connect to the TDI optical imaging camera (2). The second air-floating platform (6) is connected to a collimator (7). The output end of the collimator (7) is opposite to the input end of the TDI optical imaging camera (2), and the output port diameter of the collimator (7) is larger than the effective receiving port diameter of the input end of the TDI optical imaging camera (2). The input end of the collimator (7) is connected to the experimental chamber window (8). The focal plane of the collimator (7) is located outside the experimental chamber window (8). The experimental chamber window (8) is sealed to the side wall of the experimental chamber (1). The experimental chamber window (8) is used for beam transmission. The output end of the focal plane mechanism (9) is opposite to the experimental chamber window (8). The focal plane mechanism (9) is used to output simulated static and dynamic targets in various states at the focal plane of the collimator (7). The control system (10) is electrically connected to the six-degree-of-freedom adjustment mechanism (3), the first air flotation platform (5), the second air flotation platform (6), and the focal plane mechanism (9).

2. The optical transfer function measurement device for a TDI optical imaging camera according to claim 1, characterized in that, The focal plane mechanism (9) includes a one-dimensional translation stage a (901), a one-dimensional air-bearing translation stage (902), a one-dimensional translation stage b (903), a conventional target mechanism (904), a push-broom target mechanism (905), a blackbody light source (906), and an integrating sphere light source (907). The light emission axes of the blackbody light source (906) and the integrating sphere light source (907) are parallel to each other, and their bottoms are both connected to the working end of a one-dimensional translation stage a (901). The moving direction of the working end of the one-dimensional translation stage a (901) is perpendicular to the light emission axes of the blackbody light source (906) and the integrating sphere light source (907). The bottom of the conventional target mechanism (904) and the push-broom target mechanism (905) are both connected to the working end of the one-dimensional air-floating translation stage (902). The moving direction of the working end of the one-dimensional air-floating translation stage (902) is parallel to the moving direction of the working end of the one-dimensional translation stage a (901). The bottom of the one-dimensional translation stage a (901) and the one-dimensional air-floating translation stage (902) are both connected to the working end of the one-dimensional translation stage b (903). The one-dimensional air-floating translation stage (902) is set close to the experimental chamber window (8). The working end of the one-dimensional translation stage b (903) moves in a direction parallel to the light-emitting optical axis of the blackbody light source (906) and the integrating sphere light source (907), which is used to drive the conventional target mechanism (904) or the push-broom target mechanism (905) to move closer to or away from the experimental chamber window (8). The bottom of the one-dimensional translation stage b (903) is connected to the base (11) by a support frame; The control terminals of the one-dimensional translation stage a (901), the one-dimensional air-floating translation stage (902), and the one-dimensional translation stage b (903) are all connected to the control system (10), and the working ends of the one-dimensional translation stage a (901), the one-dimensional air-floating translation stage (902), and the one-dimensional translation stage b (903) are moved by the control system (10). The control system (10) is electrically connected to the push-broom target mechanism (905), the blackbody light source (906), and the integrating sphere light source (907).

3. The optical transfer function measurement device for a TDI optical imaging camera according to claim 2, characterized in that, The focal plane mechanism (9) also includes a housing; The bottom of the outer shell is connected to a support frame, and the one-dimensional translation stage a (901), one-dimensional air-floating translation stage (902), one-dimensional translation stage b (903), conventional target mechanism (904), push-broom target mechanism (905), blackbody light source (906), and integrating sphere light source (907) are all installed inside the outer shell.

4. The optical transfer function measurement device for a TDI optical imaging camera according to claim 2, characterized in that, The conventional target mechanism (904) is used to install conventional targets, which include a star target plate, a resolution plate, and a reticle plate. The push-broom target mechanism (905) includes a rotating structure for mounting a specific push-broom stripe plate target and enabling the target to spin.

5. A method for measuring the optical transfer function of a TDI optical imaging camera, characterized in that, Using the optical transfer function measurement device for a TDI optical imaging camera according to any one of claims 1-4, the method includes the following steps: Step 1: Fix the bottom of the experimental chamber (1) on the optical platform, connect the TDI optical imaging camera (2) to the working end of the six-degree-of-freedom adjustment mechanism (3), turn on the second air-floating platform (6) to be in air-floating state, and adjust the optical axis of the TDI optical imaging camera (2) to be initially aligned with the central axis of the collimator (7) through the six-degree-of-freedom adjustment mechanism (3). Step 2: Adjust the focal plane mechanism (9) to output the simulated static target at the focal plane position of the collimator (7), and incident it onto the input end of the TDI optical imaging camera (2) through the experimental chamber window (8) and the collimator (7). Adjust the six-degree-of-freedom adjustment mechanism (3) to align the optical axis of the TDI optical imaging camera (2) with the central axis of the collimator (7), and record the working end position of the six-degree-of-freedom adjustment mechanism (3) as zero. Step 3: Adjust the focal plane mechanism (9) of the TDI optical imaging camera (2) according to the TDI array direction to output the simulated static target, set the simulated environment of the experimental chamber (1), adjust the straightness of the TDI detector of the TDI optical imaging camera (2) and test the static optical transfer function to obtain the static optical transfer function parameters. Step 4: According to the scanning frequency requirements of the TDI optical imaging camera (2), adjust the output of the focal plane mechanism (9) to simulate the dynamic target, set up the simulation environment in the experimental chamber (1), and perform dynamic optical transfer function test on the TDI optical imaging camera (2) to obtain the dynamic optical transfer function. Step 5: Adjust the azimuth and pitch attitude of the working end of the six-degree-of-freedom adjustment mechanism (3) through the control system (10), and repeat steps 3 and 4 to obtain the static optical transfer function parameters and dynamic optical transfer function under different attitudes.

6. The method for measuring the optical transfer function of a TDI optical imaging camera according to claim 5, characterized in that, Step 2 is as follows: Step 2.1: Control the working end of the one-dimensional air-floating translation stage (902) through the control system (10) to move the conventional target mechanism (904) to the focal plane position of the collimator (7), and move the working end of the one-dimensional translation stage a (901) so that the blackbody light source (906) or the integrating sphere light source (907) is opposite to the conventional target mechanism (904). The blackbody light source (906) or the integrating sphere light source (907) simulates the light source, and the conventional target mechanism (904) emits a simulated static target. Step 2.2: The simulated static target enters the experimental chamber (1) through the experimental chamber window (8), and is emitted as a parallel beam by the collimator (7), which is then incident on the TDI detector target surface of the TDI optical imaging camera (2). Step 2.3: Activate the six-degree-of-freedom adjustment mechanism (3), the first air-float platform (5), and the second air-float platform (6), adjust the azimuth and pitch attitude of the six-degree-of-freedom adjustment mechanism (3), align the optical axis of the TDI optical imaging camera (2) with the central axis of the collimator (7), record the working end position parameters of the six-degree-of-freedom adjustment mechanism (3), and record it as the zero position.

7. The method for measuring the optical transfer function of a TDI optical imaging camera according to claim 6, characterized in that, Step 3 specifically involves: The one-dimensional air-floating translation stage (902) moves the push-broom target mechanism (905) to the center of the focal plane of the collimator (7). According to the TDI array line direction of the TDI optical imaging camera (2), the push-broom target mechanism (905) is rotated so that the direction of the scribing line on the stripe plate target of the push-broom target mechanism (905) is consistent with the direction of the TDI detector integration series of the TDI optical imaging camera (2). The experimental chamber (1) is set up to simulate the environment. Images are acquired through the working end of the TDI optical imaging camera (2). The static optical transfer function parameters are tested according to the acquired images. At the same time, the straightness of the TDI detector of the TDI optical imaging camera (2) is adjusted.

8. The method for measuring the optical transfer function of a TDI optical imaging camera according to claim 7, characterized in that, The rotating push-broom target mechanism (905) ensures that the direction of the scribing lines on the striped target of the push-broom target mechanism (905) is consistent with the direction of the integration series of the TDI detector of the TDI optical imaging camera (2). Specifically, the rotation direction of the target is as follows: Adjust the spin of the target on the push-broom target mechanism (905) and observe the stripe image acquired by the TDI optical imaging camera (2). When the contrast of the acquired stripe image is the highest, the direction of the scribing line on the stripe plate target of the push-broom target mechanism (905) is consistent with the direction of the TDI detector integration series of the TDI optical imaging camera (2).

9. The method for measuring the optical transfer function of a TDI optical imaging camera according to claim 8, characterized in that, Step 4 is as follows: Step 4.1: Rotate the striped target of the push-broom target mechanism (905) by 90 degrees, and set the motion frequency of the one-dimensional air-floating translation stage (902) according to the scanning frequency requirements of the TDI detector of the TDI optical imaging camera (2). Step 4.2: Control the one-dimensional air-floating translation stage (902) through the control system (10) to drive the push-broom target mechanism (905) to move, so as to realize the simulation of dynamic target in dynamic optical transfer function test; Step 4.3: Set up a simulated environment for the experimental chamber (1), and use the TDI optical imaging camera (2) to acquire a dynamic target image of the focal plane position of the collimator (7), and obtain the dynamic optical transfer function based on the dynamic target image.

10. The method for measuring the optical transfer function of a TDI optical imaging camera according to claim 9, characterized in that, The calculation formulas for the static optical transfer function parameters in step 3 and the dynamic optical transfer function in step 4 are as follows: In the formula, MTF represents the static optical transfer function parameter or the dynamic optical transfer function, and DN... w This indicates reading the grayscale output value corresponding to the white stripes in the image, DN. b DN represents the grayscale output value corresponding to the black stripes in the image. B This represents the background grayscale output value.

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