An aerial reconnaissance camera electronic system supporting a function of compensating for an anamorphic image shift and a method of compensating for an anamorphic image shift

Abstract

The application provides an aerial reconnaissance camera electronic system supporting an allometric image motion compensation function and an allometric image motion compensation method. The aerial reconnaissance camera electronic system supporting the allometric image motion compensation function comprises an allometric image motion inertial navigation module, an allometric image motion parameter calculation module, an allometric image motion control grouping module, a camera control module, an allometric image motion frequency control module and a combined TDICCD module. The allometric image motion compensation is realized by charge transfer of the TDICCD module, the allometric image motion compensation can be realized without additional increase of system hardware devices, and the imaging system quality, volume, power consumption and cost can be reduced. The allometric image motion compensation method can guarantee the signal-to-noise ratio requirement of the optical system image plane imaging and can reduce the complexity of the electronic circuit and the control system caused by excessive fragmentation and grouping.

Description

Technical Field

[0001] This invention relates to the field of aerospace technology, and in particular to an electronic system for an aerial reconnaissance camera that supports allometric image shift compensation and an allometric image shift compensation method. Background Technology

[0002] During reconnaissance operations, reconnaissance aircraft often need to fly at high speeds and low altitudes (high speed-to-high altitude ratio) to evade radar surveillance. In such cases, image motion blur is unavoidable in aerial imaging. The formation of image motion blur is closely related to the aircraft's flight attitude; different parameters such as flight speed, altitude, roll angle, yaw angle, and pitch angle will produce different image motion patterns. Specifically, when the aircraft flies sideways or the camera is tilted to the side, the aerial camera on the aircraft is in a slanted-view operating state. At this time, different positions on the imaging target surface will experience image motion at different speeds, generating complex motion-blurred images.

[0003] Image shift compensation techniques commonly used in aerial cameras, both domestically and internationally, include mechanical image shift compensation, optical image shift compensation, and image algorithm image shift compensation. Mechanical image shift compensation utilizes a mechanical structure to move the photosensitive medium during camera exposure, compensating for image shift as much as possible. Mechanical image shift compensation systems require extremely high structural precision, reliability, and stability; it demands that the motion vector of the photosensitive medium be consistent in magnitude and direction with the motion vector of the optical image. This compensation technique is suitable for image shift caused by aircraft roll, pitch, and camera scanning. The advantage of mechanical compensation is that the compensation speed is uniform across all points on the imaging target surface and no additional optical system is required. However, it demands high precision in the operation and manufacturing of the mechanical structure, requires high-power transmission devices, and, due to its inherent limitations, it is difficult to effectively compensate for all image shift situations. Furthermore, mechanical compensation systems significantly increase the weight and size of aerial cameras. Therefore, mechanical compensation is gradually being replaced by newer image shift compensation methods. Optical image shift compensation works by rotating or moving optical elements according to the principle of aligning with the image shift vector on the camera's image plane, so that the light rays form an opposite image shift vector on the image plane, thus suppressing image shift blur. The most commonly used optical image shift compensation method is the scanning mirror method. Optical image shift compensation optics are small, lightweight, and easy to control. Besides compensating for forward image shift, it can also compensate for image shift caused by aircraft pitch and yaw. This technology is mainly used in frame-type and panoramic cameras. Image algorithm image shift compensation is a method of post-processing to restore existing image-shifted blurred images using image algorithms. It typically involves post-analysis and restoration of the image. The theoretical basis of image algorithm image shift compensation is the assumption that a blurred image can be obtained by convolving a sharp image with a point spread function (PSF). By performing inverse convolution on the blurred image, a sharp image can be obtained. Based on this principle, image restoration processing is performed on degraded images to achieve image shift compensation. Mechanical and optical image shift compensation technologies involve large, heavy, and expensive equipment, which is very detrimental to equipment portability and limits compensation accuracy. The latter two image shift compensation technologies, with their smaller size and lighter weight, represent the future development trend of image shift compensation technology.

[0004] Currently, none of the aerial reconnaissance cameras have integrated allometric image shift compensation, which seriously restricts the development of my country's aerial camera research and development level. In addition, the current aerial reconnaissance cameras have problems with large size and weight.

[0005] Given the current limitations of aerial reconnaissance cameras, such as large size and weight and lack of heterodynamic image shift compensation, further improvements are necessary. Summary of the Invention

[0006] Based on this, the present invention proposes an electronic system for an aerial reconnaissance camera that supports allometric image shift compensation and an allometric image shift compensation method, so as to solve or partially solve the problems existing in the prior art.

[0007] In a first aspect, the present invention provides an electronic system for an aerial reconnaissance camera that supports allometric image shift compensation, comprising:

[0008] The system includes an allometric image motion inertial navigation module, an allometric image motion parameter calculation module, an allometric image motion control grouping module, a camera control module, an allometric image motion frequency control module, and a combined TDICCD module.

[0009] The inertial navigation module for allometric image motion is electrically connected to the allometric image motion parameter calculation module. The inertial navigation module for allometric image motion is used to collect parameters of the aerial camera, aircraft, and detector.

[0010] The allometric image shift parameter calculation module is used to calculate the parameters required for allometric image shift compensation based on the parameters of the aerial camera, aircraft, and detector.

[0011] The allometric image shift parameter calculation module is electrically connected to the allometric image shift control grouping module, the camera control module, and the allometric image shift frequency control module, respectively.

[0012] The allometric image shift control group module, the camera control module, and the allometric image shift frequency control module are all electrically connected to the combined TDICCD module.

[0013] The allotropic image shift control grouping module is used to receive the TDICCD module grouping of parameters required for allotropic image shift compensation calculated by the allotropic image shift parameter calculation module.

[0014] The camera control module is used to receive the parameters required for all-velocity image shift compensation calculated by the all-velocity image shift parameter calculation module and generate a camera control signal.

[0015] The allometric image shift frequency control module is used to receive the parameters required for allometric image shift compensation calculated by the allometric image shift parameter calculation module and control the combined TDICCD module to perform charge transfer to achieve allometric image shift compensation, while converting the optical signal into an electrical signal.

[0016] Preferably, the aerial reconnaissance camera electronic system supporting allometric image shift compensation further includes a combined TDICCD driving module, which is electrically connected to the combined TDICCD module. The combined TDICCD driving module is used to drive the combined TDICCD module to image and perform charge transfer to achieve allometric image shift compensation, while converting the optical signal into an electrical signal.

[0017] Preferably, the aerial reconnaissance camera electronic system supporting the allometric image shift compensation function further includes an allometric image shift image processing module, which is electrically connected to the combined TDICCD drive module. The allometric image shift image processing module is used to perform image processing on the allometric image shift compensation image signal of the combined TDICCD module.

[0018] Preferably, the aerial reconnaissance camera electronic system supporting the allometric image shift compensation function further includes an allometric image shift image compression module, which is electrically connected to the allometric image shift image processing module. The allometric image shift image compression module is used to compress the image signal processed by the allometric image shift image processing module.

[0019] Preferably, the aerial reconnaissance camera electronic system supporting the allometric image shift compensation function further includes an allometric image shift image storage module and an allometric image shift image display module. The allometric image shift image storage module is electrically connected to the allometric image shift compression module and the allometric image shift display module, respectively. The allometric image shift image storage module is used to store the compressed and allometric image shift compensated image; the allometric image shift image display module is used to display the compressed and allometric image shift compensated image.

[0020] Preferably, in the aerial reconnaissance camera electronic system supporting allometric image shift compensation, the combined TDICCD module is composed of multiple sets of TDICCDs. The combined TDICCD module is used for imaging and charge transfer to achieve allometric image shift compensation, while converting optical signals into electrical signals.

[0021] Preferably, the aerial reconnaissance camera electronic system supporting the allometric image shift compensation function further includes a power supply module, which is electrically connected to the combined TDICCD module, and the power supply module is used to supply power to the combined TDICCD module.

[0022] Secondly, the present invention also provides a method for compensating for all-velocity image shift based on the aforementioned electronic system for an aerial reconnaissance camera that supports all-velocity image shift compensation, comprising the following steps:

[0023] The allometric image-shifting inertial navigation module acquires parameters from the aerial camera, aircraft, and detector.

[0024] The allometric image shift parameter calculation module calculates the parameters required for allometric image shift compensation based on the parameters of the aerial camera, aircraft, and detector.

[0025] The allometric image shift control grouping module receives the TDICCD module grouping of parameters required for allometric image shift compensation calculated by the allometric image shift parameter calculation module.

[0026] The camera control module receives the parameters required for all-velocity image motion compensation calculated by the all-velocity image motion parameter calculation module and generates a camera control signal.

[0027] The allometric image shift frequency control module receives the parameters required for allometric image shift compensation calculated by the allometric image shift parameter calculation module, controls the combined TDICCD module, and performs charge transfer under the drive of the combined TDICCD drive module to achieve allometric image shift compensation, while converting the optical signal into an electrical signal.

[0028] The allometric image shift image processing module performs image processing on the image signal compensated by the combined TDICCD module;

[0029] The allometric image compression module compresses the image signal processed by the allometric image processing module;

[0030] The allometric image storage module stores the compressed and compensated allometric image.

[0031] The allometric image display module displays the compressed and compensated allometric image.

[0032] Preferably, in the above-mentioned allometric image shift compensation method, the parameters of the aerial camera, aircraft, and detector include flight altitude, flight speed, tilt angle, focal length, exposure time, CCD pixel size, target size, and slant distance.

[0033] The parameters required for the allometric image shift compensation include the number of blocks, the frequency required for each column of TDICCD, and the camera exposure time.

[0034] Preferably, in the aforementioned allometric image shift compensation method, the camera control signals include start, stop, dimming, focusing, and exposure time control.

[0035] The electronic system for an aerial reconnaissance camera supporting allometric image shift compensation and the allometric image shift imaging compensation method of the present invention have the following advantages over the prior art:

[0036] 1. The aerial reconnaissance camera electronic system of the present invention, which supports allometric image shift compensation, includes allometric image shift compensation.

[0037] The system includes an inertial navigation module, a heterogeneous image motion parameter calculation module, a heterogeneous image motion control grouping module, a camera control module, a heterogeneous image motion frequency control module, and a combined TDICCD module. It utilizes the TDICCD module for charge transfer to compensate for heterogeneous image motion, which can achieve heterogeneous image motion compensation without adding additional system hardware, thereby reducing the quality, size, power consumption, and cost of the imaging system.

[0038] 2. The aerial reconnaissance camera electronic system of the present invention that supports the function of allometric image shift compensation also includes a combined TDICCD driving module. The combined TDICCD driving module is used to drive the combined DICCD module to image and perform charge transfer to perform allometric image shift compensation, while converting the optical signal into an electrical signal.

[0039] 3. The aerial reconnaissance camera electronic system supporting allometric image shift compensation function of the present invention further includes an allometric image shift image processing module, an allometric image shift image compression module, an allometric image shift image storage module, and an allometric image shift image display module; the allometric image shift image processing module performs image processing on the allometric image shift compensation image signal of the combined module; the allometric image shift image compression module compresses the image signal processed by the allometric image shift image processing module; the allometric image shift image storage module stores the compressed allometric image shift compensated image; and the allometric image shift image display module displays the compressed allometric image shift compensated image.

[0040] 4. The image shift compensation method of the present invention performs image shift compensation by combining the TDICCD module under the drive of the combined TDICCD driving module. This image shift compensation method not only ensures the signal-to-noise ratio requirement of the image plane imaging of the optical system, but also reduces the complexity of electronic circuits and control systems caused by excessive segmentation and grouping. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 A schematic diagram of the principle of allometric image shift in aviation and a schematic diagram of allometric image shift on the target surface;

[0043] Figure 2 This is a schematic diagram of allotropic image shift on the target surface.

[0044] Figure 3 This is a schematic diagram of the electronic system of the aerial reconnaissance camera that supports the allometric image shift compensation function in this application.

[0045] Figure 4 This is a schematic diagram of the combined TDICCD module in one embodiment of this application;

[0046] Figure 5 This is a flowchart illustrating the image motion compensation method for an aerial reconnaissance camera electronic system that supports the image motion compensation function of this application. Detailed Implementation

[0047] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0049] This application provides an electronic system for an aerial reconnaissance camera that supports allometric image shift compensation, such as... Figure 3 As shown, it includes: an allometric image motion inertial navigation module 10, an allometric image motion parameter calculation module 11, an allometric image motion control grouping module 12, a camera control module 13, an allometric image motion frequency control module 14, and a combined TDICCD module 15;

[0050] Among them, the allometric image motion inertial navigation module 10 is electrically connected to the allometric image motion parameter calculation module 11, and the allometric image motion inertial navigation module 10 is used to collect parameters of the aerial camera, aircraft and detector.

[0051] The allometric image shift parameter calculation module 11 is used to calculate the parameters required for allometric image shift compensation based on the parameters of the aerial camera, aircraft, and detector.

[0052] The allometric image motion parameter calculation module 11 is electrically connected to the allometric image motion control grouping module 12, the camera control module 13, and the allometric image motion frequency control module 14, respectively.

[0053] The allometric image shift control group module 12, the camera control module 13, and the allometric image shift frequency control module 14 are all electrically connected to the combined TDICCD module 15.

[0054] The allometric image shift control grouping module 12 is used to receive the allometric image shift compensation parameter control combination TDICCD module 15 grouping calculated by the allometric image shift parameter calculation module 11;

[0055] Camera control module 13 is used to receive the parameters required for allometric image motion compensation calculated by allometric image motion parameter calculation module 11 and generate camera control signals.

[0056] The allometric image shift frequency control module 14 is used to receive the parameters required for allometric image shift compensation calculated by the allometric image shift parameter calculation module 11 and control the combined TDICCD module 15 to perform charge transfer to achieve allometric image shift compensation, while converting the optical signal into an electrical signal.

[0057] It should be noted that the aerial reconnaissance camera electronic system supporting allometric image shift compensation function in this application includes an allometric image shift inertial navigation module 10, an allometric image shift parameter calculation module 11, an allometric image shift control grouping module 12, a camera control module 13, an allometric image shift frequency control module 14, and a combined TDICCD module 15; wherein, the allometric image shift inertial navigation module 10 is electrically connected to the allometric image shift parameter calculation module 11, and the allometric image shift inertial navigation module 10 is used to collect parameters of the aerial camera, aircraft, and detector; specifically, the aerial camera, aircraft, and detector... The detector parameters include flight altitude, flight speed, tilt angle, focal length, exposure time, CCD pixel size, target size, slant range, etc.; the allometric image shift inertial navigation module is developed using the MCIMX6U6AVM08AC microcontroller; the allometric image shift parameter calculation module 11 is used to calculate the parameters required for allometric image shift compensation based on the parameters of the aerial camera, aircraft, and detector; specifically, the parameters required for allometric image shift compensation include the number of blocks, the frequency required for each column of TDICCD, camera exposure time, etc.; the allometric image shift parameter calculation module 11 is developed using a DSP. The TMS320C6455BCTZA was developed; the allometric image shift parameter calculation module 11 is electrically connected to the allometric image shift control group module 12, the camera control module 13, and the allometric image shift frequency control module 14, respectively; the allometric image shift control group module 12, the camera control module 13, and the allometric image shift frequency control module 14 are all electrically connected to the combined TDICCD module 15; the allometric image shift control group module 12 is used to receive the parameters required for allometric image shift compensation calculated by the allometric image shift parameter calculation module 11 and control the grouping of the combined TDICCD module 15; specifically, the allometric image shift parameter calculation module 11 sends the calculated number of blocks... The data is sent to the allometric image shift control grouping module 12, which controls the TDICCD module 15 to group data according to the number of received blocks. The combined TDICCD module is used for imaging and allometric image shift compensation, and at the same time converts the light signal into an electrical signal. The camera control module 13 is used to receive the parameters required for allometric image shift compensation calculated by the allometric image shift parameter calculation module 11 and generate camera control signals. Specifically, the camera control module 13 is used to receive the exposure time parameters calculated by the allometric image shift parameter calculation module 11 and generate camera control signals. Camera control signals include start, stop, dimming, focusing, and controlling exposure time. The allometric image shift frequency control module 14 is used to receive the parameters required for allometric image shift compensation calculated by the allometric image shift parameter calculation module and control the combined TDICCD module 15 to perform charge transfer for allometric image shift compensation, while converting the optical signal into an electrical signal. Specifically, the allometric image shift frequency control module 14 is used to receive the frequency required for each column of TDICCD calculated by the allometric image shift parameter calculation module, control the charge of each column of TDICCD to perform charge transfer for allometric image shift compensation, and the allometric image shift frequency control module is developed by the microcontroller MCIMX6U6AVM08AC.

[0058] This application presents an electronic system for an aerial reconnaissance camera supporting allometric image shift compensation. The system includes an allometric image shift inertial navigation module, an allometric image shift parameter calculation module, an allometric image shift control grouping module, a camera control module, an allometric image shift frequency control module, and a combined TDICCD module. It utilizes the TDICCD module for charge transfer to compensate for allometric image shift, achieving compensation without adding additional system hardware. This reduces the imaging system's quality, size, power consumption, and cost. The allometric image shift compensation method of this application ensures the required signal-to-noise ratio for the optical system's image plane while simultaneously reducing the complexity of electronic circuitry and control systems caused by excessive segmentation and grouping. In practical aerial camera system imaging, this method can be used as an effective way to compensate for allometric image shift during tilted imaging.

[0059] In some embodiments, a combined TDICCD driving module 16 is also included. The combined TDICCD driving module 16 is electrically connected to the combined TDICCD module 15. The combined TDICCD driving module 16 is used to drive the combined TDICCD module 15 to image and perform charge transfer to achieve allometric image shift compensation, while converting the optical signal into an electrical signal.

[0060] Specifically, the combined TDICCD driver module 16 is used to drive the combined TDICCD module 15 to form an image, and to amplify, clamp, and perform dual correlation sampling of the electrical signal, thus forming an integrated device for the combined TDICCD driver module.

[0061] In some embodiments, the system further includes a heterogeneous image shift image processing module 17, which is electrically connected to the combined TDICCD driving module 16. The heterogeneous image shift image processing module 17 is used to perform image processing on the heterogeneous image shift compensation image signal of the combined TDICCD module 15.

[0062] Specifically, the combined TDICCD driver module 16 sends the image signal of the combined TDICCD module 15 with the image compensation for the image velocity shift to the image processing module 17 with the image velocity shift. The image processing module 17 then processes the image signal with the image velocity shift compensation. The image processing module 17 is responsible for image processing such as contrast adjustment, filtering, and radiosity correction to generate the image with the image velocity shift compensation. The image processing module 17 with the image velocity shift compensation is developed using FPGA AC7A200.

[0063] In some embodiments, the image further includes a heterogeneous image motion image compression module 18, which is electrically connected to the heterogeneous image motion image processing module 17. The heterogeneous image motion image compression module 18 is used to compress the image signal processed by the heterogeneous image motion image processing module 17.

[0064] Specifically, the image compression module 18 is developed using the dedicated FPGA AC7A200 chip.

[0065] In some embodiments, the system further includes a torsion motion image storage module 19 and a torsion motion image display module 20. The torsion motion image storage module 19 is electrically connected to the torsion motion image compression module 18 and the torsion motion image display module 20, respectively. The torsion motion image storage module 19 is used to store the compressed torsion motion compensated image; the torsion motion image display module 20 is used to display the compressed torsion motion compensated image.

[0066] The image storage module 19 is developed using a dedicated development board, NVIDIA Jetson; the image display module 20 is developed using the image acquisition card VCE-CLPCIE01 and the display control software VS2015.

[0067] In some embodiments, the combined TDICCD module 15 is composed of multiple sets of TDICCDs spliced ​​together. For example... Figure 4 As shown, the combined TDICCD module 15 is composed of 10 TDICCDs staggered together, specifically CCD1, CCD2, CCD3, CCD4, CCD5, CCD6, CCD7, CCD8, CCD9, and CCD10. Each TDICCD has 8192 effective pixels, a pixel size of 10μm, and an optical system focal length f' = 7000mm.

[0068] In some embodiments, a power module 21 is also included, which is electrically connected to the combined TDICCD module 15, and the power module 21 is used to supply power to the combined TDICCD module 15. Specifically, the power module 21 utilizes a dedicated power module.

[0069] Based on the same inventive concept, this application also provides a method for compensating for all-velocity image shift in an aerial reconnaissance camera electronic system that supports the above-mentioned all-velocity image shift compensation function, comprising the following steps:

[0070] S1, the allometric image-shifting inertial navigation module acquires parameters from the aerial camera, aircraft, and detector;

[0071] S2, the allometric image shift parameter calculation module calculates the parameters required for allometric image shift compensation based on the parameters of the aerial camera, aircraft, and detector;

[0072] S3, The allometric image shift control grouping module receives the allometric image shift compensation parameter control combination TDICCD module grouping calculated by the allometric image shift parameter calculation module;

[0073] S4. The camera control module receives the parameters required for all-velocity image motion compensation calculated by the all-velocity image motion parameter calculation module and generates a camera control signal.

[0074] S5. The allometric image shift frequency control module receives the parameters required for allometric image shift compensation calculated by the allometric image shift parameter calculation module, controls the combined TDICCD module, and performs charge transfer under the drive of the combined TDICCD drive module to realize allometric image shift compensation, while converting the optical signal into an electrical signal.

[0075] S6, the image processing module performs image processing on the image signal compensated by the combined TDICCD module for the image motion of the image motion.

[0076] S7, the image compression module compresses the image signal processed by the image processing module at different speeds of image motion;

[0077] S8, the allometric image storage module stores the compressed and compensated allometric image.

[0078] S9, the allometric image display module displays the compressed and compensated allometric image.

[0079] In some implementations, the parameters of aerial cameras, aircraft, and detectors include flight altitude, flight speed, tilt angle, focal length, exposure time, CCD pixel size, target size, and slant distance;

[0080] The parameters required for the allometric image shift compensation include the number of blocks, the frequency required for each column of TDICCD, and the camera exposure time.

[0081] In some implementations, camera control signals include start, stop, dimming, focusing, and controlling exposure time.

[0082] The principle of the allometric image shift compensation method of this application will be further explained below.

[0083] Specifically, the causes of allometric image shift in aerial cameras are as follows:

[0084] During reconnaissance, reconnaissance aircraft need to fly at high speed and low altitude to evade enemy radar surveillance. High-speed, low-altitude flight greatly improves the aircraft's battlefield survivability and deep reconnaissance and surveillance capabilities. However, this causes severe image shift on the target surface during aerial imaging, resulting in blurred aerial images and affecting the effectiveness of aerial reconnaissance. During forward flight, due to the aircraft's attitude adjustments (such as side-flying) or the adjustment of the aerial camera lens's pitch angle, the aerial camera operates in an oblique viewing state. A schematic diagram of the target surface is shown below. Figure 2 As shown, when a CCD camera with an area array is tilted during imaging, due to the aircraft's tilt, within a single ground area, the forward image migration velocity of a near target on the image plane is the same in direction but different in magnitude compared to the forward image migration velocity of a far target. This forward image migration velocity, which is equal in direction but unequal in magnitude, is defined as heterogeneous image migration.

[0085] The specific principle of using the parameters required for allometric image shift compensation in this application for allometric image shift compensation is as follows.

[0086] When an aerial CCD camera is tilted during photography, due to the aircraft's tilt, within a single frame of ground area, the forward image migration velocity of a near target on the image plane is the same in direction but unequal in magnitude compared to the forward image migration velocity of a far target. This forward image migration velocity, with equal direction but unequal magnitude, is defined as anisotropic image migration. The camera's depression angle and field of view are the main causes of anisotropic image migration. In addition, aircraft attitude angles, such as the aircraft's roll angle, also produce anisotropic image migration. The causes, magnitude, and direction of anisotropic image migration will be studied in detail below. Figure 1 As shown, the image motion rate at the focal plane along the aircraft's flight direction is not constant throughout the entire array. It is determined by the range of tilt and the slant distance R (i.e., the distance from the lens to the corresponding point on the ground). The larger the range, the smaller the image motion rate at the focal plane. Specifically, in the vertical flight direction, the image motion rate at a certain point is equal to the image motion rate V. P2 for:

[0087]

[0088] Where ε is half the field of view, δ is the camera's depression angle, f is the lens focal length, V is the aircraft's flight speed, and R is the slant distance, i.e., the distance from the lens to a point on the ground corresponding to the focal plane. The focal plane array (FPA) can be further described geometrically as follows:

[0089]

[0090] Here, for any given θ, y is the distance from a point on the ground area photographed perpendicular to the flight direction to the centerline. As shown below:

[0091]

[0092] Where δ is the depression angle, i.e., the angle between the center of the field of view and the horizontal line; H is the altitude of the aircraft. Therefore:

[0093]

[0094] The impact of image shift perpendicular to the focal plane on image quality can be derived by calculating the image shift modulation transfer function (MTF) of the focal plane array. From Equation 4, for a given lens focal length f, depression angle δ, field of view angle ε, and aircraft speed-to-altitude ratio V / H, the velocity v at a point y in the image perpendicular to the focal plane... y It can be represented as:

[0095]

[0096] Calculations and analysis show that asynchronous image speed is only related to the camera's lateral viewing angle and tilt angle, and is not related to the aircraft's longitudinal viewing angle.

[0097] When the aircraft's speed-to-altitude ratio decreases, the image migration speed also decreases accordingly. At this point, maintaining the resolution of the ground image is futile, regardless of the focal length of the lens used. The distance L that the image migrates from a point on the focal plane parallel to the flight direction is related to the aircraft's flight speed v and the total time t. The total time t is the sum of the exposure times of the focal plane array (i.e., the shutter opening time). According to the modulation transfer function (MTF), the degree of image blur M is a function of L.

[0098]

[0099] Among them, f N This refers to the Nyquist space frequency, the highest frequency we are interested in. Assume the aircraft's ground-to-ground speed is V, ranging from 10 m / s to 50 m / s; the flight altitude is H, taking values ​​of 3000 m or 5000 m; the lateral pitch angle of the lens is δ; the lens focal length is f; the lens half-field angle is θ; and the velocity of the distant point on the ground is... The image motion velocity of the ground near point on the CCD array is: Image motion velocity ratio between near and far points When ε takes a fixed value, V N / V F The value increases as the pitch angle δ decreases. When δ varies within the range [90°, θ), V N / V F The value range of δ is [1, +∞), which indicates that the lateral pitch angle of the lens has a great influence on the difference in image movement velocity of the corresponding image points on the CCD surface of near and far objects on the ground. As δ decreases, the difference in image movement velocity can no longer be approximated as negligible.

[0100] Image motion velocity matching is achieved by adjusting the line frequency of the TDICCD. Therefore, when aerial cameras are used for tilted imaging, a grouped heterogeneous velocity matching strategy can be adopted to improve the image quality of focal plane edge points. Grouped heterogeneous velocity image motion matching involves first grouping the focal plane, and then independently adjusting the line frequency of the TDICCD within each group, using the image motion velocity of the center point of each group as a reference. Theoretically, the more groups there are, the closer the focal plane edge points are to the reference point, and therefore the higher the MTF caused by image motion velocity errors. However, the TDICCDs currently used in China do not have single-chip frequency division control functionality; that is, the maximum number of groups depends on how many TDICCDs are stitched together to form the focal plane.

[0101] The aerial camera studied in this application has a focal plane composed of 10 staggered TDICCDs, with each TDICCD having an effective pixel count of 8192 and a pixel size of 10μm. The optical system has a focal length of f' = 7000mm.

[0102] When achieving large-angle tilt imaging with an aerial camera, simply adjusting the integral order or using grouping and frequency division control strategies is insufficient to meet the desired image quality requirements. Therefore, it's crucial to prioritize adjusting the integral order based on the environmental conditions of the aerial camera's imaging position, combining this with grouping and frequency division to achieve heterogeneous image migration matching. Selecting an appropriate frequency division strategy while adjusting the TDICCD's integral order considers both image sharpness and contrast requirements, while also reducing the difficulty of subsequent image stitching and matching. This is because the choice of integral order affects the system's signal-to-noise ratio (SNR), which in turn affects image sharpness and contrast; the choice of frequency division strategy directly impacts image quality, and degradation in image quality can render the image indistinguishable and unrecognizable. This strategy, combining integral order adjustment and frequency division control, significantly reduces the complexity of the control circuit, thereby enabling sharp tilt imaging.

[0103] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An electronic system for an aerial reconnaissance camera supporting allometric image shift compensation, characterized in that, include: Allometric Image Shift Inertial Navigation Module, Allometric Image Shift Parameter Calculation Module, Allometric Image Shift Control Grouping Module, Phase Machine control module, heterogeneous image shift frequency control module and combined TDICCD module; The inertial navigation module for allometric image motion is electrically connected to the allometric image motion parameter calculation module. The inertial navigation module for allometric image motion is used to collect parameters of the aerial camera, aircraft and detector. The allometric image motion parameter calculation module is used to calculate the parameters required for allometric image motion compensation based on the parameters of the aerial camera, aircraft, and detector. The allometric image shift parameter calculation module is electrically connected to the allometric image shift control grouping module, the camera control module, and the allometric image shift frequency control module, respectively. The allometric image shift control group module, the camera control module, and the allometric image shift frequency control module are all electrically connected to the combined TDICCD module; The allotropic image shift control grouping module is used to receive the TDICCD module grouping of parameters required for allotropic image shift compensation calculated by the allotropic image shift parameter calculation module. The camera control module is used to receive the parameters required for all-velocity image shift compensation calculated by the all-velocity image shift parameter calculation module and generate a camera control signal. The allometric image shift frequency control module is used to receive the parameters required for allometric image shift compensation calculated by the allometric image shift parameter calculation module and control the required frequency of each column of TDICCD in the combined TDICCD module, thereby controlling the charge of each column of TDICCD to perform charge transfer, realizing allometric image shift compensation, and at the same time converting the optical signal into an electrical signal. The parameters required for the allometric image shift compensation include the number of blocks, the frequency required for each column of TDICCD, and the camera exposure time.

2. The aerial reconnaissance camera electronic system supporting allometric image shift compensation function as described in claim 1, Its features are, It also includes a combined TDICCD driving module, which is electrically connected to the combined TDICCD module. The combined TDICCD driving module is used to drive the combined TDICCD module to image and perform charge transfer to achieve allometric image shift compensation, while converting the optical signal into an electrical signal.

3. The aerial reconnaissance camera electronic system supporting allometric image shift compensation function as described in claim 2, Its features are, It also includes a heterogeneous image shift image processing module, which is electrically connected to the combined TDICCD driving module. The heterogeneous image shift image processing module is used to perform image processing on the heterogeneous image shift compensation image signal of the combined TDICCD module.

4. The aerial reconnaissance camera electronic system supporting allometric image shift compensation function as described in claim 3, characterized in that, It also includes a heterogeneous image motion image compression module, which is electrically connected to the heterogeneous image motion image processing module. The heterogeneous image motion image compression module is used to compress the image signal processed by the heterogeneous image motion image processing module.

5. The aerial reconnaissance camera electronic system supporting allometric image shift compensation function as described in claim 4, characterized in that, It also includes a torsion motion image storage module and a torsion motion image display module. The torsion motion image storage module is electrically connected to the torsion motion image compression module and the torsion motion image display module, respectively. The torsion motion image storage module is used to store the compressed torsion motion compensated image; the torsion motion image display module is used to display the compressed torsion motion compensated image.

6. The aerial reconnaissance camera electronic system supporting allometric image shift compensation as described in claim 1, characterized in that, The combined TDICCD module is composed of multiple TDICCDs stitched together. The combined TDICCD module is used for imaging and charge transfer to achieve allometric image shift compensation, and at the same time converts optical signals into electrical signals.

7. The aerial reconnaissance camera electronic system supporting allometric image shift compensation function as described in any one of claims 1 to 6, characterized in that, It also includes a power module, which is electrically connected to the combined TDICCD module, and the power module is used to supply power to the combined TDICCD module.

8. A method for compensating for allometric image shift in an aerial reconnaissance camera electronic system supporting allometric image shift compensation as described in any one of claims 1 to 7, characterized in that, Includes the following steps: The allometric image-shifting inertial navigation module acquires parameters from the aerial camera, aircraft, and detector. The allometric image shift parameter calculation module calculates the parameters required for allometric image shift compensation based on the parameters of the aerial camera, aircraft, and detector. The allometric image shift control grouping module receives the TDICCD module grouping of parameters required for allometric image shift compensation calculated by the allometric image shift parameter calculation module. The camera control module receives the parameters required for all-velocity image motion compensation calculated by the all-velocity image motion parameter calculation module and generates a camera control signal. The allometric image shift frequency control module is used to receive the parameters required for allometric image shift compensation calculated by the allometric image shift parameter calculation module, control the combined TDICCD module, and perform charge transfer under the drive of the combined TDICCD driving module to realize allometric image shift compensation, while converting the optical signal into an electrical signal. The allometric image shift image processing module performs image processing on the image signal compensated by the combined TDICCD module; The allometric image compression module compresses the image signal processed by the allometric image processing module; The allometric image storage module stores the compressed and compensated allometric image. The allometric image display module displays the compressed and compensated allometric image.

9. The allometric image shift compensation method as described in claim 8, characterized in that, The parameters of the aerial camera, aircraft, and detector include flight altitude, flight speed, tilt angle, focal length, exposure time, CCD pixel size, target size, and slant distance. The parameters required for the allometric image shift compensation include the number of blocks, the frequency required for each column of TDICCD, and the camera exposure time.

10. The allometric image shift compensation method as described in claim 8, characterized in that, The control camera Signals include start, stop, dimming, focusing, and controlling exposure time.

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