Radar image enhancement method, device and equipment based on polarization regulation and control

Abstract

The invention relates to a radar image enhancement method, device and equipment based on polarization regulation and control. The method comprises the following steps: acquiring a complete polarization radar image of a target by using a polarization radar system; uniformly sampling the polarization parameter space according to the polarization parameter descriptor to obtain different transmit-receive polarization vectors, and constructing a transmit-receive polarization vector set; performing polarization regulation and control on the complete polarization radar image according to the transceiving polarization vector set, acquiring variable polarization images corresponding to different transceiving polarization vectors according to a digital weighting mode, and constructing a variable polarization image sequence; and performing fusion processing on the variable polarization image sequence to obtain an enhanced radar image. The method can be used for target structure inversion and contour extraction.

Description

Technical Field

[0001] The present application relates to the field of radar detection technology, and in particular to a radar image enhancement method, device and equipment based on polarization control. Background Art

[0002] By using radar equipment to detect targets of interest, radar images of targets can be obtained, including synthetic aperture radar (SAR) images and inverse synthetic aperture radar (ISAR) images. Based on radar images, many typical applications can be achieved, such as target detection, classification and recognition, structure inversion, and attitude estimation.

[0003] Polarization is an important property of electromagnetic waves. Polarimetric radar can obtain dual-polarization images or full-polarization images of targets through a set of orthogonal dual-polarization antennas. Polarimetric radar images contain rich scattering structure information of targets. However, due to the different response strengths of target scattering structures under different transmit and receive polarizations, there are differences in the amplitude strengths of different parts of the target in the images of each sub-channel of the polarimetric radar, resulting in incomplete target structure. On the one hand, the image of a single polarization channel is difficult to reflect the complete structure and outline of the target; on the other hand, the existing polarization channel fusion method mainly uses polarization scattering components to synthesize color images, and each channel uses normalization methods to control the image amplitude. The weak scattering structure of the target will still be affected by the strong scattering structure, making it difficult to obtain a complete outline. Therefore, how to make full use of the polarization scattering information of the target in the radar image and obtain an image that can reflect the clear and complete outline of the target through enhancement is an unresolved problem. Summary of the invention

[0004] Based on this, it is necessary to provide a radar image enhancement method, device and equipment based on polarization control that can be used for target structure inversion and contour extraction in order to solve the above technical problems.

[0005] A radar image enhancement method based on polarization control, the method comprising: Use polarimetric radar system to obtain full polarimetric radar images of the target; According to the polarization parameter descriptor, the polarization parameter space is uniformly sampled to obtain different transmit and receive polarization vectors, and a transmit and receive polarization vector set is constructed; According to the set of transmit and receive polarization vectors, the full polarization radar image is polarized and controlled, and the variable polarization images corresponding to different transmit and receive polarization vectors are obtained in a digital weighted manner to construct a variable polarization image sequence; The polarization-varying image sequence is fused to obtain the enhanced radar image.

[0006] In one embodiment, obtaining full polarization radar image data of a target includes: A set of orthogonal dual-polarized antennas with polarization states of X and Y are used to acquire radar images, and four polarization channel images are obtained, which are recorded as XX, XY, YX, and YY, respectively, where XY represents the radar image obtained by Y-polarization transmission and X-polarization reception, XX represents the radar image obtained by X-polarization transmission and X-polarization reception, YX represents the radar image obtained by X-polarization transmission and Y-polarization reception, and YY represents the radar image obtained by Y-polarization transmission and Y-polarization reception; The radar image is converted into a fully polarized radar image under horizontal and vertical polarization: ; Among them, H represents horizontal polarization antenna, V represents vertical polarization antenna, and It is the ellipticity angle difference and elliptical inclination angle difference of the polarization ellipse parameters corresponding to XY polarization and HV polarization.

[0007] In one embodiment, the polarization parameter descriptor includes a polarization ellipse descriptor, a polarization phase descriptor, and a Jones vector descriptor; based on the polarization parameter descriptor, the polarization parameter space is uniformly sampled to obtain different transmit and receive polarization vectors, and a transmit and receive polarization vector set is constructed, including: If the polarization parameter descriptor is a polarization ellipse descriptor ( , ), then the value range of the polarization ellipse descriptor is determined as , ; The sampling points of the polarization parameters are set as , , the polarization parameters are obtained as ( , ), , , then the polarization vector obtained using the polarization ellipse descriptor is .

[0008] In one embodiment, if the polarization parameter descriptor is a polarization phase descriptor ( , ), then the value range of the polarization phase descriptor is determined as , ; The sampling points of the polarization parameters are set as , , the polarization parameters are obtained as ( , ), , , then the polarization vector obtained using the polarization phase descriptor is .

[0009] In one embodiment, if the polarization parameter descriptor is a Jones vector descriptor ( , ), then the value range of the Jones vector descriptor is determined as ; The sampling points of the polarization parameters are set as , , the polarization parameters are obtained as ( , ), , , then the polarization vector obtained using the Jones vector descriptor is .

[0010] In one embodiment, polarization control is performed on the full polarization radar image according to the transmit and receive polarization vector set, and variable polarization images corresponding to different transmit and receive polarization vectors are obtained in a digital weighted manner, including: Use any polarization vector in the polarization vector set as the transmit polarization Or receive vector , , the polarization image is obtained as ; The superscript T represents the transpose operation.

[0011] In one embodiment, the polarization-variable image sequence is fused to obtain an enhanced radar image, including: For each image in the polarization image sequence, calculate the local minimum point and the local maximum point respectively; count the number of times each pixel is the local maximum point and the number of local minima ; If the number of local maximum points is greater than the number of local minimum points , then the point is a strong scattering point, otherwise This point is a weak scattering point; For any pixel in the image , take out all the results corresponding to the pixel point in the polarization image sequence, and get the pixel sequence , pixel sequence The maximum amplitude is , the mean is , assign values ​​to the scattering points according to the strength of the scattering points in the image, and obtain the pixel value of the pixel point after image fusion , which is the result of enhancing the corresponding position of the pixel in the image; All pixels in the image are processed sequentially to obtain the enhanced radar image.

[0012] In one embodiment, assigning a value to a scattering point according to the strength of the scattering point in the image to obtain a pixel value of the pixel point after the image is fused includes: The scattering points are assigned values ​​according to the strength of the scattering points in the image, and the pixel value of the pixel after image fusion is obtained. .

[0013] A radar image enhancement device based on polarization control, the device comprising: A full polarization radar image acquisition module is used to acquire a full polarization radar image of a target using a polarization radar system; A module for constructing a transmit / receive polarization vector set is used to uniformly sample the polarization parameter space according to the polarization parameter descriptor, obtain different transmit / receive polarization vectors, and construct a transmit / receive polarization vector set; A polarization-variable image sequence construction module is used to perform polarization control on the full polarization radar image according to the transmit and receive polarization vector set, obtain polarization-variable images corresponding to different transmit and receive polarization vectors in a digital weighted manner, and construct a polarization-variable image sequence; The radar image enhancement module is used to fuse the polarization image sequence to obtain the enhanced radar image.

[0014] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are implemented: Use polarimetric radar system to obtain full polarimetric radar images of the target; According to the polarization parameter descriptor, the polarization parameter space is uniformly sampled to obtain different transmit and receive polarization vectors, and a transmit and receive polarization vector set is constructed; According to the set of transmit and receive polarization vectors, the full polarization radar image is polarized and controlled, and the variable polarization images corresponding to different transmit and receive polarization vectors are obtained in a digital weighted manner to construct a variable polarization image sequence; The polarization-varying image sequence is fused to obtain the enhanced radar image.

[0015] The above-mentioned radar image enhancement method, device and equipment based on polarization control, firstly use the polarization radar system to obtain the full polarization radar image of the target, which can fully reflect the scattering information of the target. Uniform sampling of the polarization parameter space according to the polarization parameter descriptor can ensure that multiple polarization states are covered, thereby constructing a rich set of transmit and receive polarization vectors, which is helpful to fully obtain the response of the target under different transmit and receive polarization excitation conditions, and then enhance the understanding of the strong and weak scattering mechanism of the target. Polarization control of the full polarization radar image by digital weighting can generate variable polarization images corresponding to different transmit and receive polarization vectors, so that the image features can be adjusted according to the needs, and the polarization state that can best highlight the target structure can be selected, thereby reducing the interference of strong scattering structures on weak scattering structures. Fusion processing of the variable polarization image sequence can effectively integrate information from different polarization channels, enhance the clarity and contour of the target, suppress noise and unnecessary interference, and highlight the structural features of the target, and finally obtain a more visible enhanced image. The present application not only improves the ability of target structure inversion and contour extraction, but also ensures the high robustness and low complexity of the image, and finally achieves a clear and accurate target enhanced image. This strategy is expected to solve the problems of incomplete structure and blurred outline in existing polarimetric radar image processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a process of a radar image enhancement method based on polarization control in an embodiment; Figure 2 A schematic diagram of a satellite model in one embodiment; Figure 3 A schematic diagram of a fusion process of a polarimetric radar image sequence in another embodiment; Figure 4 A schematic diagram of the determination results of strong scattering points and weak scattering points in one embodiment; Figure 5 FIG. 1 is a schematic diagram of the result before polarization radar image enhancement in one embodiment; wherein Figure 5 (a) is a schematic diagram of the HH polarization channel image before enhancement. Figure 5 (b) is a schematic diagram of edge detection results of HH polarization channel image; Figure 6 FIG. 1 is a schematic diagram of the result after polarization radar image enhancement in one embodiment; wherein, Figure 6 (a) is a schematic diagram of the enhanced image. Figure 6 (b) is a schematic diagram of the edge detection results of the enhanced image; Figure 7 is a structural block diagram of a radar image enhancement device based on polarization control in one embodiment; Figure 8 FIG. 4 is a diagram showing the internal structure of a computer device in one embodiment. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0018] In one embodiment, Figure 1 As shown, a radar image enhancement method based on polarization control is provided, comprising the following steps: Step 102: Acquire a full polarization radar image of the target using a polarization radar system.

[0019] Polarimetric radar technology can provide richer target scattering information than a single polarization system by transmitting and receiving electromagnetic waves in different polarization states. The acquisition of fully polarized radar images means that the system can capture all polarization information scattered back from the target surface, usually including a combination of horizontal polarization (H) and vertical polarization (V) components, such as HH, HV, VH, and VV. This fully polarized data provides a more comprehensive description of target features, especially in complex backgrounds. For example, some materials may have strong scattering characteristics in one polarization state and weaker scattering characteristics in another state. Through fully polarized images, we can get a full picture of the target and better understand its physical properties and geometric structure. This lays the foundation for subsequent structural inversion and contour extraction.

[0020] Step 104: uniformly sample the polarization parameter space according to the polarization parameter descriptor to obtain different transmit and receive polarization vectors, and construct a transmit and receive polarization vector set.

[0021] The polarization parameter space is a multidimensional space that describes the polarization state. By uniformly sampling this space, different transmit and receive polarization vectors can be obtained. These vectors refer to the scattering characteristics formed by the interaction between electromagnetic waves and targets in specific transmit and receive polarization states. The advantage of uniform sampling is that it can cover all possible states in the polarization space, ensuring that a sufficient variety of scattering information is captured. This can avoid missing important features in certain polarization states, thereby improving the ability to identify and analyze targets. After constructing the transmit and receive polarization vector set, the corresponding polarization state can be flexibly selected as needed, thereby enhancing the effectiveness of subsequent image processing.

[0022] Step 106, polarization control is performed on the full polarization radar image according to the transmit and receive polarization vector set, and variable polarization images corresponding to different transmit and receive polarization vectors are obtained in a digital weighted manner to construct a variable polarization image sequence.

[0023] Through the constructed set of transmit and receive polarization vectors, the full polarization radar image is polarized and regulated, and the variable polarization images corresponding to different transmit and receive polarization vectors are generated by digital weighting. The core of this process is digital weighting, that is, dynamically adjusting the weight of each polarization channel in image reconstruction according to its importance or characteristics. The construction of the variable polarization image sequence makes it possible to generate images for specific polarization states, thereby enhancing certain features of the target. It not only helps to suppress the interference of strong scattering structures on weak scattering structures, but also can highlight the edges and contours of the target, making it more obvious in a complex background.

[0024] Step 108: performing fusion processing on the variable polarization image sequence to obtain an enhanced radar image.

[0025] Fusion processing of the polarization-varying image sequence is a key step in this application. Fusion technology can effectively integrate the information obtained under different polarization states to generate an enhanced image that combines the advantages of each channel. Through fusion processing, the following functions can be achieved: 1. Complementary information may exist in different polarization images, which can form a clearer target outline after fusion, reduce the influence of noise and artifacts, and enhance the target structure.

[0026] 2. By integrating information from multiple polarization states, the algorithm’s adaptability and robustness to the target are enhanced, so that it can perform well in different environments and conditions and improve its robustness.

[0027] 3. Although image fusion usually involves certain calculations, the pre-constructed transmit and receive polarization vector set and effective digital weighting strategy can simplify the calculation process and improve processing efficiency. This low-complexity processing method makes real-time applications possible and reduces complexity.

[0028] In the above-mentioned radar image enhancement method based on polarization control, the full polarization radar image of the target is first obtained by using the polarization radar system to fully reflect the scattering information of the target. Uniform sampling of the polarization parameter space according to the polarization parameter descriptor can ensure that multiple polarization states are covered, thereby constructing a rich set of transmit and receive polarization vectors, which is helpful to fully obtain the response of the target under different transmit and receive polarization excitation conditions, thereby enhancing the understanding of the strong and weak scattering mechanism of the target. Polarization control of the full polarization radar image by digital weighting can generate variable polarization images corresponding to different transmit and receive polarization vectors, so that the image features can be adjusted according to the needs, and the polarization state that can best highlight the target structure can be selected, thereby reducing the interference of strong scattering structures on weak scattering structures. Fusion processing of the variable polarization image sequence can effectively integrate information from different polarization channels, enhance the clarity and contour of the target, suppress noise and unnecessary interference, and highlight the structural features of the target, and finally obtain a more visible enhanced image. The present application not only improves the ability of target structure inversion and contour extraction, but also ensures the high robustness and low complexity of the image, and finally achieves a clear and accurate target enhanced image. This strategy is expected to solve the problems of incomplete structure and blurred outline in existing polarimetric radar image processing.

[0029] In one embodiment, obtaining full polarization radar image data of a target includes: A set of orthogonal dual-polarized antennas with polarization states of X and Y are used to acquire radar images, and four polarization channel images are obtained, which are recorded as XX, XY, YX, and YY, respectively, where XY represents the radar image obtained by Y-polarization transmission and X-polarization reception, XX represents the radar image obtained by X-polarization transmission and X-polarization reception, YX represents the radar image obtained by X-polarization transmission and Y-polarization reception, and YY represents the radar image obtained by Y-polarization transmission and Y-polarization reception; The radar image is converted into a fully polarized radar image under horizontal and vertical polarization: ; Among them, H represents horizontal polarization antenna, V represents vertical polarization antenna, and It is the ellipticity angle difference and elliptical inclination angle difference of the polarization ellipse parameters corresponding to XY polarization and HV polarization.

[0030] In one embodiment, the polarization parameter descriptor includes a polarization ellipse descriptor, a polarization phase descriptor, and a Jones vector descriptor; based on the polarization parameter descriptor, the polarization parameter space is uniformly sampled to obtain different transmit and receive polarization vectors, and a transmit and receive polarization vector set is constructed, including: If the polarization parameter descriptor is a polarization ellipse descriptor ( , ), then the value range of the polarization ellipse descriptor is determined as , ; The sampling points of the polarization parameters are set as , , the polarization parameters are obtained as ( , ), , , then the polarization vector obtained using the polarization ellipse descriptor is .

[0031] In one embodiment, if the polarization parameter descriptor is a polarization phase descriptor ( , ), then the value range of the polarization phase descriptor is determined as , ; The sampling points of the polarization parameters are set as , , the polarization parameters are obtained as ( , ), , , then the polarization vector obtained using the polarization phase descriptor is .

[0032] In one embodiment, if the polarization parameter descriptor is a Jones vector descriptor ( , ), then the value range of the Jones vector descriptor is determined as ; The sampling points of the polarization parameters are set as , , the polarization parameters are obtained as ( , ), , , then the polarization vector obtained using the Jones vector descriptor is .

[0033] In one embodiment, polarization control is performed on the full polarization radar image according to the transmit and receive polarization vector set, and variable polarization images corresponding to different transmit and receive polarization vectors are obtained in a digital weighted manner, including: Use any polarization vector in the polarization vector set as the transmit polarization Or receive vector , , the polarization image is obtained as ; The superscript T represents the transpose operation.

[0034] In one embodiment, the polarization-variable image sequence is fused to obtain an enhanced radar image, including: For each image in the polarization image sequence, calculate the local minimum point and the local maximum point respectively; count the number of times each pixel is the local maximum point and the number of local minima ; If the number of local maximum points is greater than the number of local minimum points , then the point is a strong scattering point, otherwise This point is a weak scattering point; For any pixel in the image , take out all the results corresponding to the pixel point in the polarization image sequence, and get the pixel sequence , pixel sequence The maximum amplitude is , the mean is , assign values ​​to the scattering points according to the strength of the scattering points in the image, and obtain the pixel value of the pixel point after image fusion , which is the result of enhancing the corresponding position of the pixel in the image; All pixels in the image are processed sequentially to obtain the enhanced radar image.

[0035] In one embodiment, assigning a value to a scattering point according to the strength of the scattering point in the image to obtain a pixel value of the pixel point after the image is fused includes: The scattering points are assigned values ​​according to the strength of the scattering points in the image, and the pixel value of the pixel after image fusion is obtained. .

[0036] In a specific embodiment, Figure 2 The satellite model shown is used for simulation analysis.

[0037] In step 102, a full polarization radar image of the target is obtained. Figure 2The CAD model of the target shown is imported into the FEKO electromagnetic simulation software. The longitudinal dimension of the target is 40.9 meters and the lateral dimension is 17.8 meters. The simulation center frequency is set to 10GHz, the bandwidth is 400MHz, the radar incident pitch angle is 45°, and the azimuth angle is 10°. The convolution back projection imaging method is used to image the acquired full polarization electromagnetic scattering data, and 4 sets of polarization radar images are obtained with a resolution of 0.375 meters. The full polarization radar image of the target is obtained, including four sets of images: HH, HV, VH, and VV. In the co-polarization channels HH and VV, the vertical structure of the solar panel part of the target is clearer, but the overall outline is incomplete, and the main part of the satellite is three strong scattering points. In the cross-polarization channels HV and VH, the target sailboard structure disappears, and there are only three bright spots in the main part, and the bright spot intensity in the middle position is the largest. In short, it is difficult to effectively extract the outline and structure of the target using single-polarization radar images.

[0038] Figure 3 The processing flow of using polarization control to process polarimetric radar images to obtain enhanced images is demonstrated. First, polarization control is performed on the polarimetric radar image to obtain a variable polarization radar image sequence. The image sequence contains radar images under different transmit and receive polarization states, and the number of images in the sequence is the number of transmit and receive polarization states. Secondly, the number of times each pixel point is a local maximum point or a local minimum point in each image of the image sequence is counted, and each pixel point is judged to be a strong scattering point or a weak scattering point based on this. Finally, according to the judgment results of strong and weak scattering points, the maximum value or mean value of the corresponding position of each pixel point in the image sequence is fused into a new image, which is the enhanced radar image.

[0039] Figure 4 The results of judging strong and weak scattering points are shown. It can be seen that the vertical edge points of the target solar panels are correctly detected as strong scattering points, as marked by the dotted boxes in the figure, and the rest are weak scattering points. Figure 5 and Figure 6 As shown, Figure 5 FIG. 1 is a schematic diagram of the result before polarization radar image enhancement in one embodiment; wherein Figure 5 (a) is a schematic diagram of the HH polarization channel image before enhancement. Figure 5 (b) is a schematic diagram of edge detection results of HH polarization channel image; Figure 6 FIG. 1 is a schematic diagram of the result after polarization radar image enhancement in one embodiment; wherein Figure 6 (a) is a schematic diagram of the enhanced image. Figure 6(b) is a schematic diagram of the edge detection result of the enhanced image. It can be seen that the sailboard structure of the target in the enhanced image is clearly visible. Comparing the edge detection results, it can be seen that only part of the strong scattering structure can be detected before enhancement. The edge detection result after enhancement can detect the complete outline of the target. In summary, this application, as a preprocessing method, can effectively improve the accuracy and efficiency of subsequent structure and contour extraction.

[0040] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0041] In one embodiment, Figure 7 As shown, a radar image enhancement device based on polarization control is provided, including: a full polarization radar image acquisition module 702, a transmit and receive polarization vector set construction module 704, a variable polarization image sequence construction module 706 and a radar image enhancement module 708, wherein: A full polarization radar image acquisition module 702 is used to acquire a full polarization radar image of a target using a polarization radar system; The module 704 for constructing a transmit / receive polarization vector set is used to uniformly sample the polarization parameter space according to the polarization parameter descriptor, obtain different transmit / receive polarization vectors, and construct a transmit / receive polarization vector set; The polarization-variable image sequence construction module 706 is used to perform polarization control on the full polarization radar image according to the transmit and receive polarization vector set, obtain polarization-variable images corresponding to different transmit and receive polarization vectors in a digital weighted manner, and construct a polarization-variable image sequence; The radar image enhancement module 708 is used to perform fusion processing on the variable polarization image sequence to obtain an enhanced radar image.

[0042] For the specific definition of the radar image enhancement device based on polarization control, please refer to the definition of the radar image enhancement method based on polarization control in the above text, which will not be repeated here. Each module in the above-mentioned radar image enhancement device based on polarization control can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0043] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 8 As shown. The computer device includes a processor, a memory, a network interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a radar image enhancement method based on polarization regulation is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a key, trackball or touchpad set on the computer device housing, or an external keyboard, touchpad or mouse, etc.

[0044] Those skilled in the art will understand that Figure 8 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0045] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0046] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A radar image enhancement method based on polarization control, characterized in that: The method comprises: Use polarimetric radar system to obtain full polarimetric radar images of the target; According to the polarization parameter descriptor, the polarization parameter space is uniformly sampled to obtain different transmit and receive polarization vectors, and a transmit and receive polarization vector set is constructed; According to the transmit and receive polarization vector set, polarization control is performed on the full polarization radar image, and variable polarization images corresponding to different transmit and receive polarization vectors are obtained in a digital weighted manner to construct a variable polarization image sequence; The polarization image sequence is fused to obtain an enhanced radar image, including: For each image in the polarization image sequence, calculate the local minimum point and the local maximum point respectively; count the number of times each pixel is the local maximum point and the number of local minima ; If the number of local maximum points is greater than the number of local minimum points , then the point is a strong scattering point, otherwise This point is a weak scattering point; For any pixel in the image , take out all the results corresponding to the pixel point in the polarization image sequence, and get the pixel sequence , pixel sequence The maximum amplitude is , the mean is , assign values ​​to the scattering points according to the strength of the scattering points in the image, and obtain the pixel value of the pixel point after image fusion , which is the result of the corresponding position of the pixel in the enhanced image; all pixels in the image are processed in sequence to obtain the enhanced radar image.

2. The method according to claim 1, characterized in that Acquire full polarization radar image data of the target, including: A set of orthogonal dual-polarized antennas with polarization states of X and Y are used to acquire radar images, and four polarization channel images are obtained, which are recorded as XX, XY, YX, and YY, respectively, where XY represents the radar image obtained by Y-polarization transmission and X-polarization reception, XX represents the radar image obtained by X-polarization transmission and X-polarization reception, YX represents the radar image obtained by X-polarization transmission and Y-polarization reception, and YY represents the radar image obtained by Y-polarization transmission and Y-polarization reception; The radar image is converted into a fully polarized radar image under horizontal and vertical polarization: ； Among them, H represents horizontal polarization antenna, V represents vertical polarization antenna, and It is the ellipticity angle difference and elliptical inclination angle difference of the polarization ellipse parameters corresponding to XY polarization and HV polarization.

3. The method according to claim 1, characterized in that The polarization parameter descriptor includes a polarization ellipse descriptor, a polarization phase descriptor and a Jones vector descriptor; Based on the polarization parameter descriptor, the polarization parameter space is uniformly sampled to obtain different transmit and receive polarization vectors, and a transmit and receive polarization vector set is constructed, including: If the polarization parameter descriptor is a polarization ellipse descriptor ( , ), then the value range of the polarization ellipse descriptor is determined as , ; The sampling points of the polarization parameters are set as , the polarization parameters are obtained as ( , ), , , then the polarization vector obtained using the polarization ellipse descriptor is 。 4. The method according to claim 3, characterized in that The method further comprises: If the polarization parameter descriptor is a polarization phase descriptor ( , ), then the value range of the polarization phase descriptor is determined as , ; The sampling points of the polarization parameters are set as , the polarization parameters are obtained as ( , ), , , then the polarization vector obtained using the polarization phase descriptor is 。 5. The method according to claim 3, characterized in that: The method further comprises: If the polarization parameter descriptor is a Jones vector descriptor ( , ), then the value range of the Jones vector descriptor is determined as ; The sampling points of the polarization parameters are set as , the polarization parameters are obtained as ( , ), , , then the polarization vector obtained using the Jones vector descriptor is 。 6. The method according to claim 2, characterized in that According to the receiving and transmitting polarization vector set, polarization control is performed on the full polarization radar image, and variable polarization images corresponding to different receiving and transmitting polarization vectors are obtained in a digital weighted manner, including: Use any polarization vector in the polarization vector set as the transmit polarization Or receive vector , , the polarization image is obtained as ； The superscript T represents the transpose operation.

7. The method according to claim 1, characterized in that The scattering points are assigned values ​​according to the strength of the scattering points in the image, and the pixel value of the pixel point after the image fusion is obtained, including: The scattering points are assigned values ​​according to the strength of the scattering points in the image, and the pixel value of the pixel after image fusion is obtained. 。 8. A radar image enhancement device based on polarization control, characterized in that: The device comprises: A full polarization radar image acquisition module is used to acquire a full polarization radar image of a target using a polarization radar system; A module for constructing a transmit / receive polarization vector set is used to uniformly sample the polarization parameter space according to the polarization parameter descriptor, obtain different transmit / receive polarization vectors, and construct a transmit / receive polarization vector set; A polarization-variable image sequence construction module is used to perform polarization control on the full-polarization radar image according to the transmit-receive polarization vector set, obtain polarization-variable images corresponding to different transmit-receive polarization vectors in a digital weighted manner, and construct a polarization-variable image sequence; The radar image enhancement module is used to fuse the polarization image sequence to obtain the enhanced radar image, including: for each image in the polarization image sequence, respectively calculating the local minimum point and the local maximum point; counting the number of times each pixel point is the local maximum point and the number of local minima ; If the number of local maximum points is greater than the number of local minimum points , then the point is a strong scattering point, otherwise This point is a weak scattering point; For any pixel in the image , take out all the results corresponding to the pixel point in the polarization image sequence, and get the pixel sequence , pixel sequence The maximum amplitude is , the mean is , assign values ​​to the scattering points according to the strength of the scattering points in the image, and obtain the pixel value of the pixel point after image fusion , which is the result of the corresponding position of the pixel in the enhanced image; all pixels in the image are processed in sequence to obtain the enhanced radar image.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

Images