A ground simulation method for space remote sensing image of vibration degradation

Abstract

The present application relates to the field of remote sensing image processing and aerospace technology, and particularly relates to a space remote sensing image ground simulation method for vibration degradation, which simulates the influence of satellite vibration on imaging quality under different exposure times in the observation of a stationary orbit surface array staring camera to the earth, and establishes a satellite vibration simulation model in different directions; the satellite vibration simulation model is established in the following manner: a simulation optical platform for simulating the degradation of space remote sensing images caused by platform vibration is built on the ground; the horizontal or vertical motion of the simulation rotating platform is simulated, so that the rotation of the rotating platform is used to simulate the vibration of the actual on-orbit platform; the present application can simulate the degradation of space remote sensing images caused by on-orbit platform vibration, and is an effective implementation method for guiding the restoration algorithm.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of remote sensing image processing and aerospace technology, and particularly relates to a space remote sensing image ground simulation method for vibration degradation. BACKGROUND

[0002] With the continuous progress of science and technology, countries have invested a lot of manpower, financial resources and material resources in the development of space optical remote sensing equipment and platforms, and space remote sensing technology has made great progress. Because the amount of information obtained by the space remote sensing imaging system is huge, it has been widely used in commercial, military and civilian applications;

[0003] At present, with the increasing demand for information and the increasing demand for observation ability and function of optical remote sensors, the space remote sensing imaging system is developing towards higher definition, higher resolution, larger width and lower cost. At this time, the stability of the imaging system is particularly important;

[0004] However, the space remote sensing imaging system is affected by many factors in the imaging link, resulting in degradation of imaging quality. The most important influencing factors include satellite platform, optical system, imaging environment, electronic system, etc.

[0005] With the progress of optical system design and satellite attitude control technology, the space remote sensing camera has continuously improved the ability of earth observation. The vibration-induced image degradation has become an important factor affecting the imaging quality of high-resolution remote sensing;

[0006] During the satellite imaging in orbit, the operation of the star components such as torque gyro, reaction flywheel, momentum wheel and solar sail will cause the vibration response of the camera lens. During the exposure time, the relative motion between the imaging target and the optical device focal plane will occur, the image plane will produce motion blur, and the imaging quality will be reduced;

[0007] Especially for the static orbit array staring imaging, the exposure time is relatively long, and it is more susceptible to platform vibration. Therefore, it is necessary to study the vibration compensation method.

[0008] For array staring imaging, not only higher precision vibration measurement means are needed, but also more detailed simulation models need to be established for different situations.

[0009] For degraded images, when the vibration suppression of the optical load platform is difficult, the simulation method of accurate vibration degradation is used to obtain the simulated degraded images. Finally, the high-quality remote sensing images can be obtained through image restoration. SUMMARY

[0010] The present application aims to solve the technical problem of lacking effective method for guiding the restoration algorithm of the degradation of space remote sensing image caused by the vibration of the on-orbit platform in the prior art, and provides a ground simulation method for vibration-degraded space remote sensing image.

[0011] In order to solve the above technical problems, the technical scheme of the present application is as follows:

[0012] A ground simulation method for vibration-degraded space remote sensing image, comprising:

[0013] In the observation of a stationary orbit plane array staring camera to the earth, the simulation of the influence of satellite vibration on imaging quality is carried out under different exposure times, and a satellite vibration simulation model is established in different directions;

[0014] The satellite vibration simulation model is established in the following manner: a simulation optical platform for simulating the degradation of space remote sensing image caused by platform vibration is built on the ground;

[0015] The simulation optical platform is composed of an integrating sphere 1, an edge image target 2, a collimator 3, a space camera prototype 4, a high-precision turntable 5 and a fast vision device 6;

[0016] When the simulation optical platform is vibrating, the number of pixels moved is set to , and the MTF value in the corresponding direction is reduced to times of the original MTF value, i.e. MTF ;

[0017] , wherein ;

[0018] The simulation optical platform is used for testing, and the testing process is as follows:

[0019] Step S1: simulate the degradation of space platform caused by vibration by simulating the number of moved pixels;

[0020] Step S2: according to the principle of optical imaging, the focal length , the imaging distance and the detector pixel size α obtained in the test can obtain the spatial resolution γ of the test camera as follows:

[0021] γ=α h / f ;

[0022] Step S3: assuming that the angular velocity of the simulation rotating platform is ω, the number of pixels to be moved is , and the exposure time to be adjusted is:

[0023] ;

[0024] , the exposure time can also be assumed to be The number of pixels to be moved is Then, the simulation rotating platform angular velocity ω needs to be adjusted as:

[0025] ;

[0026] In step S3, different degrees of MTF value loss are simulated by adjusting the exposure time and the speed of the rotating platform.

[0027] The simulation rotating platform is moved horizontally or longitudinally, so that the vibration of the actual on-orbit platform is simulated by using the rotation of the rotating platform.

[0028] The image is continuously collected and stored by the fast vision device 6, and the horizontal of the corresponding horizontal or longitudinal MTF value before and after the vibration is tested by the edge method.

[0029] In step S4, the vibration blurred imaging is obtained by moving the pixels n to the preset number of blurred images.

[0030] More specifically, the vibration blurred imaging is obtained by moving the pixels n to two groups of blurred images, i.e., the blurred images of n=1.25 and n=1.62.

[0031] In addition, the integrating sphere 1 is used to provide a uniform light source.

[0032] The collimator 3 is used to convert the light beam output by the edge image target 2 into a parallel light beam and incident on the focal plane detector of the spatial camera principle prototype 4.

[0033] The spatial camera principle prototype 4 is used for imaging.

[0034] The high-precision turntable 5 is used to simulate the vibration degradation of the image.

[0035] The present application has the following beneficial effects:

[0036] The simulation rotating platform is moved horizontally or longitudinally, so that the vibration of the actual on-orbit platform is simulated by using the rotation of the rotating platform.

[0037] The image is continuously collected and stored by the fast vision device 6, and the horizontal of the corresponding horizontal or longitudinal MTF value before and after the vibration is tested by the edge method.

[0038] For the vibration blurred imaging, the blurred images of n=1.25 and n=1.62 are obtained, and the image becomes blurred, and the left stripe is not clear.

[0039] The application can simulate space remote sensing image degradation caused by on-orbit platform vibration, and is an effective implementation method for guiding the restoration algorithm. BRIEF DESCRIPTION OF DRAWINGS

[0040] The application will be further described in detail below with reference to the drawings and specific embodiments.

[0041] Figure 1 A system composition schematic diagram of the ground simulation optical platform of the vibration degradation space remote sensing image of the application;

[0042] Figure 2 An optical imaging principle schematic diagram of the application;

[0043] Figure 3a A clear image of the MTF = 0.10 stable platform;

[0044] Figure 3b A simulated vibration blurred image of the MTF = 0.047;

[0045] Figure 3c A simulated vibration blurred image of the MTF = 0.022;

[0046] The reference signs in the drawings represent:

[0047] Integral sphere 1, edge image target 2, collimator 3, space camera principle prototype 4, high-precision turntable 5, fast vision device 6. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, but not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application. It should be noted that, in order to facilitate description, in the current view, the "left side" is the "first end", the "right side" is the "second end", the "upper side" is the "first end", and the "lower side" is the "second end". The purpose of such description is to clearly express the technical solutions, and should not be understood as an improper limitation on the technical solutions of the application.

[0049] Explanation of MTF: Modulation Transfer Function (MTF) is an important index representing an optical system, which describes the contrast transfer ability of the optical system. The larger the MTF is, the better the imaging quality of the system is.

[0050] The application gives simulation of the influence of satellite vibration on imaging quality under different exposure times in the earth observation of a static orbit plane array staring camera, establishes a satellite vibration simulation model in different directions, guides the restoration algorithm, and is an effective method for simulating the vibration degradation of remote sensing images.

[0051] In order to simulate the vibration degradation of space remote sensing images caused by the vibration of an on-orbit platform, a simulation optical platform for simulating the vibration degradation of space remote sensing images caused by the vibration of a platform is built on the ground, and a system composition diagram of the simulation optical platform is shown in the accompanying Figure 1 The simulation optical platform is composed of an integrating sphere 1, an edge image target 2, a collimator 3, a space camera prototype 4, a high-precision turntable 5 and a fast vision device 6.

[0052] The application aims to solve the technical problem of lacking an effective method for simulating the vibration degradation of space remote sensing images caused by the vibration of an on-orbit platform and guiding the restoration algorithm in the prior art, and provides a ground simulation method for vibration degradation of space remote sensing images.

[0053] A ground simulation method for vibration degradation of space remote sensing images, comprising:

[0054] In the earth observation of a static orbit plane array staring camera, the influence of satellite vibration on imaging quality under different exposure times is simulated, and a satellite vibration simulation model is established in different directions.

[0055] The satellite vibration simulation model is established in the following manner: a simulation optical platform for simulating the vibration degradation of space remote sensing images caused by the vibration of a platform is built on the ground, and a system composition diagram of the simulation optical platform is shown in the accompanying Figure 1 The system composition diagram of the ground simulation optical platform for vibration degradation of space remote sensing images is shown in the accompanying

[0056] The simulation optical platform is composed of an integrating sphere 1, an edge image target 2, a collimator 3, a space camera prototype 4, a high-precision turntable 5 and a fast vision device 6.

[0057] The collimator 3 is used to convert the light beam output by the edge image target 2 into a parallel light beam and make the parallel light beam incident on the focal plane detector of the space camera prototype 4.

[0058] The space camera prototype 4 is used for imaging.

[0059] The high-precision turntable 5 is used to simulate the vibration degradation of images.

[0060] When the simulation optical platform vibrates, the number of pixels moved is set to , and the MTF value in the corresponding direction is reduced to a multiple of the original MTF value, that is, δ MTF .

[0061] wherein, ;

[0062] The test is performed using the simulated optical platform, and the test process is as follows:

[0063] The degradation of the space platform caused by vibration is simulated by simulating the number of moving image elements.

[0064] According to the principle of optical imaging, the focal length of the imaging system obtained in the test , the imaging distance , and the detector element size a, the spatial resolution γ of the test camera can be obtained as follows:

[0065] γ = a h / f ;

[0066] Suppose the angular velocity of the simulated rotating platform is ω, and the number of image elements to be moved is , then the exposure time to be adjusted is:

[0067] ;

[0068] wherein, it can also be assumed that the exposure time is , the number of image elements to be moved is , and the angular velocity ω of the simulated rotating platform to be adjusted is:

[0069] ;

[0070] By adjusting the exposure time and the speed of the rotating platform, different degrees of MTF value loss can be simulated.

[0071] wherein, by simulating the transverse or longitudinal motion of the rotating platform, the rotation of the rotating platform is used to simulate the vibration of the actual on-orbit platform.

[0072] wherein, the continuous acquisition and storage of images are performed by the fast vision device 6, and the levels of the corresponding transverse or longitudinal MTF values before and after vibration are tested by the edge method. Figure 3a , and Figure 3b , and Figure 3c are three implementation cases of blurred images of different degrees of vibration.

[0073] From the visual point of view, the image of the stable platform, as shown in Figure 3a , the image stripes are easier to distinguish, and the image is clearer.

[0074] For vibration blurred imaging, the blurred images of n=1.25 and n=1.62 image elements, as shown in Figure 3b and Figure 3c , the image becomes blurred, and the left stripe is not clear.

[0075] In summary, the application can simulate the degradation of space remote sensing images caused by vibration of on-orbit platform, and is an effective implementation method for guiding the restoration algorithm.

[0076] Obviously, the above embodiments are only examples for clearly illustrating the present application, and are not intended to limit the implementation modes. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the implementation modes do not need to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for simulating ground truth of a space remote sensing image with degraded vibration, characterized in that, The application relates to a satellite vibration simulation model for establishing a satellite vibration simulation model in different directions under different exposure times in a ground observation of a static orbit plane array staring camera. The satellite vibration simulation model is established in the following manner: a simulation optical platform for simulating image degradation caused by platform vibration in space remote sensing is built on the ground; The simulation optical platform is composed of an integrating sphere (1), an edge image target (2), a collimator (3), a space camera principle prototype (4), a high-precision turntable (5) and a fast vision device (6); The simulation optical platform is used for testing, and the testing process is as follows: When the simulation optical platform is shaken, the number of pixels to be moved is set as , and the MTF value in the corresponding direction is reduced to a multiple of the original MTF value MTF ; wherein ; Step S1: the number of moving image elements is simulated to simulate the degradation of a space platform caused by vibration; h / f Step S2, according to the principle of optical imaging, the focal length of the imaging system obtained in the test , the imaging distance and the detector pixel size α, the spatial resolution γ of the test camera can be obtained as follows: γ = a The exposure time and the angular velocity of the simulation optical platform are adjusted to simulate different degrees of MTF value loss; ; Step S3, when the angular velocity of the simulation optical platform is ω, the number of pixels to be moved is Then the exposure time to be adjusted is ​ ； Or, when the exposure time of the simulation optical platform is The number of pixels to be moved is The angular velocity ω that needs to be adjusted is: ； The actual in-orbit platform vibration is simulated through the horizontal or vertical movement of the simulation optical platform; The fast vision device (6) is used for continuous image acquisition and storage, and the horizontal or vertical MTF value of the corresponding horizontal or vertical MTF value before and after vibration is tested by the edge method; Step S4: vibration blurred imaging, wherein the vibration blurred imaging includes a plurality of groups of blurred images with n moving image elements. The plurality of groups of blurred images with n moving image elements are blurred images with n=1.25 and n=1.

62.

2. The method of claim 1, wherein the method further comprises: The integrating sphere (1) is used to provide a uniform light source; 3. The method of claim 2, wherein the method further comprises: The collimator (3) is used to convert the light beam output by the edge image target (2) into a parallel light beam and to be incident on the focal plane detector of the space camera principle prototype (4); The space camera principle prototype (4) is used for imaging; The high-precision turntable (5) is used for simulating image vibration degradation. ​

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