SAR image enhancement display processing method, device, equipment and medium

Abstract

The present invention provides a SAR image enhanced display processing method, device, equipment and medium, including: obtaining SAR image data to be processed and its corresponding incident angle array; performing logarithmic quantization processing on the SAR image data to be processed to obtain quantized SAR image data; based on the incident angle array, performing incident angle gain compensation processing on the quantized SAR image data to obtain compensated SAR image data; performing percentage nonlinear stretching processing on the compensated SAR image data to obtain enhanced display target SAR image data. The present invention effectively solves the problem of poor display effect of wide-width SAR images in ocean scenes.

Description

Technical Field

[0001] The present invention relates to the field of image processing technology, and in particular to a SAR image enhancement display processing method, device, equipment and medium. Background Art

[0002] Existing commercial SAR satellite image products all use 16-bit or 32-bit to uniformly quantize satellite detection SAR data. If the scattering characteristics of the observed target in the image are too different, the display effect will be completely black or completely white. Even if some enhanced display methods are adopted, the display efficiency is acceptable in medium width (10-100km), but if the image width is too large (over 500km), the display effect is still poor. Especially in ocean scenes, the radar echo scattering characteristics of wide-width SAR images are inconsistent between the near-end perspective (incident angle less than 20 degrees) and the far-end perspective, resulting in a large difference in the echo of the near-end and far-end perspectives, with the near end bright and the far end dark, further affecting the display effect. Summary of the invention

[0003] In view of this, an object of the present invention is to provide a SAR image enhancement display processing method, device, equipment and medium to effectively solve the problem of poor display effect of wide-width SAR images in ocean scenes.

[0004] In a first aspect, an embodiment of the present invention provides a SAR image enhancement display processing method, comprising:

[0005] Obtain the SAR image data to be processed and its corresponding incident angle array;

[0006] Performing logarithmic quantization processing on the SAR image data to be processed to obtain quantized SAR image data;

[0007] Based on the incident angle array, performing incident angle gain compensation processing on the quantized SAR image data to obtain compensated SAR image data;

[0008] The compensated SAR image data is subjected to percentage nonlinear stretching processing to obtain enhanced and displayed target SAR image data.

[0009] In one embodiment, the incident angle array includes incident angle data corresponding to each pixel point at each distance inward in the SAR image data to be processed; based on the incident angle array, the step of performing incident angle gain compensation processing on the quantized SAR image data to obtain compensated SAR image data includes:

[0010] For each pixel point within each distance in the SAR image data to be processed, determine a target electromagnetic scattering model corresponding to the pixel point from candidate electromagnetic scattering models according to a threshold interval covered by the incident angle data corresponding to the pixel point, so as to generate an incident angle gain compensation value based on the incident angle data corresponding to the pixel point through the target electromagnetic scattering model;

[0011] The incident angle gain compensation value is used to perform incident angle gain compensation processing on the SAR image data to be processed to obtain compensated SAR image data.

[0012] In one embodiment, the candidate electromagnetic scattering models include: a perturbation electromagnetic scattering model, a Kirchhoff electromagnetic scattering model, and a dual-scale electromagnetic scattering model;

[0013] The step of determining a target electromagnetic scattering model corresponding to the pixel point from candidate electromagnetic scattering models according to a threshold range covered by the incident angle data corresponding to the pixel point comprises:

[0014] If the incident angle data corresponding to the pixel point is within the medium incident angle threshold interval, the perturbation electromagnetic scattering model is used as the target electromagnetic scattering model;

[0015] Alternatively, if the incident angle data corresponding to the pixel point is within a small incident angle threshold interval, the Kirchhoff electromagnetic scattering model is used as a target electromagnetic scattering model;

[0016] Alternatively, if the range of the incident angle data corresponding to the pixel point covers both the medium incident angle threshold interval and the small incident angle threshold interval, the dual-scale electromagnetic scattering model is used as the target electromagnetic scattering model.

[0017] In one embodiment, the step of performing incident angle gain compensation processing on the SAR image data to be processed by using the incident angle gain compensation value to obtain compensated SAR image data includes:

[0018] For the SAR image data to be processed, the difference between the incident angle data and the incident angle gain compensation value is calculated range-wise and pixel-wise to obtain compensated SAR image data.

[0019] In one embodiment, the step of performing percentage nonlinear stretching processing on the compensated SAR image data to obtain enhanced display target SAR image data includes:

[0020] Sorting the scattering amplitude values ​​corresponding to each pixel point in the compensated SAR image data to determine the scattering amplitude values ​​corresponding to two preset percentile points based on the sorting result;

[0021] Based on the scattering amplitude value corresponding to the preset percentile, the effective scattering amplitude value and the invalid scattering amplitude value are determined, and the invalid scattering amplitude value is adjusted to achieve percentage nonlinear stretching processing to obtain the target SAR image data after enhanced display.

[0022] In one embodiment, the preset percentile includes a first percentile and a second percentile, the first percentile is less than the second percentile, and the sum of the first percentile and the second percentile is 100%;

[0023] The step of determining a valid scattering amplitude value and an invalid scattering amplitude value based on the scattering amplitude value corresponding to the preset percentile point comprises:

[0024] The scattering amplitude value corresponding to the first percentile is used as the lower quantile, and the scattering amplitude value corresponding to the second percentile is used as the upper quantile;

[0025] The scattering amplitude value between the lower quantile and the upper quantile is a valid scattering amplitude value, and the scattering amplitude value less than the lower quantile or greater than the upper quantile is an invalid scattering amplitude value.

[0026] In one embodiment, the step of adjusting the invalid scattering amplitude value includes:

[0027] The scattering amplitude values ​​smaller than the lower quantile are replaced with the lower quantile; and the scattering amplitude values ​​larger than the upper quantile are replaced with the upper quantile.

[0028] In a second aspect, an embodiment of the present invention further provides a SAR image enhancement display processing device, comprising:

[0029] A data acquisition module is used to acquire the SAR image data to be processed and its corresponding incident angle array;

[0030] A logarithmic quantization module is used to perform logarithmic quantization on the SAR image data to be processed to obtain quantized SAR image data;

[0031] A gain compensation module, used for performing incident angle gain compensation processing on the quantized SAR image data based on the incident angle array to obtain compensated SAR image data;

[0032] The nonlinear stretching module is used to perform percentage nonlinear stretching processing on the compensated SAR image data to obtain target SAR image data after enhanced display.

[0033] In a third aspect, an embodiment of the present invention further provides an electronic device, comprising a processor and a memory, wherein the memory stores computer-executable instructions that can be executed by the processor, and the processor executes the computer-executable instructions to implement any one of the methods provided in the first aspect.

[0034] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions. When the computer-executable instructions are called and executed by a processor, the computer-executable instructions prompt the processor to implement any one of the methods provided in the first aspect.

[0035] The embodiment of the present invention provides a SAR image enhanced display processing method, device, equipment and medium. After obtaining the SAR image data to be processed and its corresponding incident angle array, the SAR image data to be processed is first logarithmically quantized to obtain quantized SAR image data; then, based on the incident angle array, the quantized SAR image data is subjected to incident angle gain compensation processing to obtain compensated SAR image data; finally, the compensated SAR image data is subjected to percentage nonlinear stretching processing to obtain enhanced display target SAR image data. The above method effectively solves the problem of poor display effect of wide-width SAR images in ocean scenes by performing three processing processes: logarithmically quantizing the SAR image data to be processed, incident angle gain compensation, and percentage linear stretching.

[0036] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0039] Figure 1 A schematic diagram of a flow chart of a SAR image enhancement display processing method provided by an embodiment of the present invention;

[0040] Figure 2A processing result diagram based on the comparison of sential1A-EM mode images (500km width) provided in an embodiment of the present invention;

[0041] Figure 3 A schematic diagram of the structure of a SAR image enhancement display processing device provided by an embodiment of the present invention;

[0042] Figure 4 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described in combination with the embodiments below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] At present, the display effect of wide-width SAR images is relatively poor. Based on this, the present invention provides a SAR image enhanced display processing method, device, equipment and medium to effectively solve the problem of poor display effect of wide-width SAR images in ocean scenes.

[0045] To facilitate understanding of this embodiment, a SAR image enhancement display processing method disclosed in an embodiment of the present invention is first described in detail. Figure 1 The flowchart of a SAR image enhancement display processing method shown in FIG. 1 mainly includes the following steps S102 to S108:

[0046] Step S102, obtaining the SAR image data to be processed and its corresponding incident angle array.

[0047] The SAR image data to be processed is wide-bandwidth SAR image data in an ocean scene (also referred to as ground-range SAR amplitude image data or two-dimensional SAR image data), and the incident angle array may also be referred to as an incident angle file or a one-dimensional incident angle array, including incident angle data corresponding to each pixel point at each distance inward in the SAR image data to be processed.

[0048] Step S104: performing logarithmic quantization processing on the SAR image data to be processed to obtain quantized SAR image data.

[0049] In one example, the original SAR image data to be processed is logarithmically quantized to obtain a gain representation corresponding to the SAR image data to be processed, that is, quantized SAR image data.

[0050] Step S106, based on the incident angle array, performing incident angle gain compensation processing on the quantized SAR image data to obtain compensated SAR image data.

[0051] In one example, the target electromagnetic scattering model corresponding to each incident angle data can be determined based on the threshold interval covered by each incident angle data and the mapping relationship between the threshold interval and the candidate electromagnetic scattering model, so as to generate an incident angle gain compensation value based on the corresponding incident angle data using the target electromagnetic scattering model, and then implement the incident angle gain compensation processing using the incident angle gain compensation value.

[0052] Step S108, performing percentage nonlinear stretching processing on the compensated SAR image data to obtain enhanced and displayed target SAR image data.

[0053] In one example, since most of the effective scattering amplitude values ​​of SAR image data are concentrated in a small central range, it is necessary to pre-set percentiles, use the scattering amplitude values ​​corresponding to the percentiles to determine the effective scattering amplitude values ​​and the invalid scattering amplitude values, and make adjustments to the invalid scattering amplitude values ​​to achieve percentage nonlinear stretching processing.

[0054] The above method provided by the embodiment of the present invention effectively solves the problem of poor display effect of wide-width SAR images in ocean scenes by performing three processing steps of logarithmic quantization, incident angle gain compensation, and percentage linear stretching on the SAR image data to be processed.

[0055] For ease of understanding, an embodiment of the present invention provides a specific implementation of a SAR image enhancement display processing method.

[0056] For the aforementioned step S102, when executing the step of obtaining the SAR image data to be processed and the corresponding incident angle array, it mainly includes: reading the ground-based SAR amplitude image data and related auxiliary data. The data matrix of the ground-based SAR amplitude image data is a complete data matrix, which is not geocoded, and can distinguish the range direction and the azimuth direction, so as to perform the incident angle gain compensation in the range direction later; the related auxiliary data is the incident angle data, and the incident angle array along the range direction is obtained.

[0057] The specific implementation is as follows:

[0058] (1) Read the ground-based SAR amplitude image data, usually in tiff format, and obtain a two-dimensional raw SAR data array Tiffdata. Its dimension is [row, col], where row is the azimuth width of the SAR image; col is the range width of the SAR image. For example, the ground-based SAR amplitude image data can be the GRD data of the European Sentinel-1, the L1C data of the GF-3 series, etc.

[0059] (2) Read the incident angle file. Obtain a one-dimensional incident angle array Incdata. Its dimension is [1,col], where col is the range width of the ground-based SAR amplitude image data, that is, the incident angle value corresponding to each range direction is obtained.

[0060] For the aforementioned step S104, when performing logarithmic quantization processing on the SAR image data to be processed to obtain the quantized SAR image data, it mainly includes: usually the original quantization value or DN value of the SAR image data to be processed; after logarithmic quantization processing, it is converted into a dB value. The purpose of the processing is to reduce the value range of the data so as to use the effective quantization bits to display more image details.

[0061] The specific implementation is as follows:

[0062] The two-dimensional raw SAR data array is converted according to the following formula to obtain the gain representation corresponding to the two-dimensional raw SAR data:

[0063] Tiffdata_dB=20*log10(Tiffdata);

[0064] Among them, Tiffdata is a two-dimensional raw SAR data array, and Tiffdata_dB is the quantized SAR image data. For different SAR satellites, the physical meaning after logarithmic processing is slightly different. For example, the domestic Gaofen-3 series satellites are usually Sigma-nought; the foreign Sentinel-1 satellite can be converted to Sigma-nought, Betta-nought or Gamma-nought.

[0065] For the aforementioned step S106, when executing the step of performing incident angle gain compensation processing on the quantized SAR image data based on the incident angle array to obtain the compensated SAR image data, it mainly includes: in the SAR image data, the near end is a small incident angle, and the far end is a large incident angle. Firstly, combining the incident angle array corresponding to the quantized SAR image data and the empirical sea surface electromagnetic scattering calculation model, the incident angle gain compensation value Sigma-nought corresponding to each incident angle (corresponding to each distance direction) is calculated; secondly, for the quantized SAR image data, the corresponding incident angle gain compensation value Sigma-nought is subtracted from each row according to the distance point to obtain the compensated SAR image data.

[0066] The specific implementation is as follows:

[0067] Step 1: for each pixel point within each distance in the SAR image data to be processed, determine the target electromagnetic scattering model corresponding to the pixel point from the candidate electromagnetic scattering models according to the threshold interval covered by the incident angle data corresponding to the pixel point, so as to generate an incident angle gain compensation value based on the incident angle data corresponding to the pixel point through the target electromagnetic scattering model.

[0068] Among them, the candidate electromagnetic scattering models include: Small Perturbation Method (SPM) electromagnetic scattering model, Kirchhoff Approximation Method (KA) electromagnetic scattering model, and Two Scale Model (TSM) electromagnetic scattering model.

[0069] In one example, if the incident angle data corresponding to the pixel point is in the medium incident angle threshold interval, the perturbation electromagnetic scattering model is used as the target electromagnetic scattering model. The medium incident angle threshold interval is the range formed by the first incident angle threshold and the second incident angle threshold, and the first incident angle threshold is less than the second incident angle threshold. Exemplarily, the SPM (Small Perturbation Method) model can be selected at medium incident angles (15° to 60°).

[0070] In one example, if the incident angle data corresponding to the pixel point is in the small incident angle threshold interval, the Kirchhoff electromagnetic scattering model is used as the target electromagnetic scattering model. The small incident angle threshold interval is also a range less than the first incident angle threshold. Exemplarily, the KA (Kirchhoff Approximation Method) model can be selected at a small incident angle (less than 15°).

[0071] In one example, if the range of the incident angle data corresponding to the pixel point covers both the medium incident angle threshold interval and the small incident angle threshold interval, the two-scale electromagnetic scattering model is used as the target electromagnetic scattering model. Exemplarily, if the range of the incident angle data covers both the small incident angle and the medium incident angle, the TSM (Two Scale Model) model can be selected.

[0072] The general expression in the electromagnetic scattering model is as follows:

[0073] NESZ=Model(θ,φ,wind_speed,wind_dir);

[0074] In this model, θ is the radar observation incident angle data, φ is the radar observation azimuth data, wind_speed is the wind speed data corresponding to the observation sea area, and wind_dir is the wind direction data corresponding to the observation sea area.

[0075] After determining the corresponding target electromagnetic scattering model, the model can be used to calculate the incident angle gain compensation value Sigma-nought corresponding to each incident angle, whose dimension is [1,col], where col is the range width of the SAR image, that is, the incident angle gain compensation value corresponding to each range is obtained. The specific calculation method uses the electromagnetic scattering model determined in the previous step, θ takes the aforementioned incident angle data Incdata, φ, wind_speed and wind_dir can take typical values, such as φ takes 90°, wind_speed takes 10m / s, and wind_dir takes 0°.

[0076] Step 2, using the incident angle gain compensation value, performs incident angle gain compensation processing on the SAR image data to be processed to obtain compensated SAR image data. Specifically, for the SAR image data to be processed, the difference between the incident angle data and the incident angle gain compensation value can be calculated range-wise and pixel-by-pixel (referred to as point-by-point per row) to obtain compensated SAR image data.

[0077] In the specific implementation, through the above calculation, the incident angle data and the incident angle gain compensation value corresponding to each pixel point in each range direction are known, and each pixel point is traversed to calculate the difference between the corresponding incident angle data Incdata and the incident angle gain compensation value Sigma-nought to obtain the compensated data corresponding to each pixel point, and then obtain the compensated SAR image data Tiffdata_dB_inc.

[0078] Even after logarithmic quantization and incident angle compensation, if the SAR image contains a strong scattering target, the limited quantization interval will not be able to fully display the backscattering value range. This is because the effective scattering amplitude values ​​of the single-view SAR amplitude image are mostly concentrated in a small range in the middle. Based on this, the purpose of the aforementioned step S108 is to reduce the impact of strong scattering targets on the display of the entire image in the ocean scene. When performing the percentage nonlinear stretching process on the compensated SAR image data to obtain the enhanced display target SAR image data, it mainly includes:

[0079] Step 1: Sort the scattering amplitude values ​​corresponding to each pixel in the compensated SAR image data to determine the scattering amplitude values ​​corresponding to two preset percentiles based on the sorting results. The preset percentiles include a first percentile and a second percentile, the first percentile is less than the second percentile, and the sum of the first percentile and the second percentile is 100%. Exemplarily, the percentile value percentile is set, usually 1% to 5%, assuming that the first percentile is 2%, the second percentile is 98%, and then the compensated SAR image data Tiffdata_dB_inc is calculated to select the scattering amplitude value at 2% and the scattering amplitude value at 98%.

[0080] Step 2: Based on the scattering amplitude value corresponding to the preset percentile point, the effective scattering amplitude value and the invalid scattering amplitude value are determined, and the invalid scattering amplitude value is adjusted to achieve percentage nonlinear stretching processing to obtain the target SAR image data after enhanced display.

[0081] In one example, the scattering amplitude value corresponding to the first percentile (such as 2%) is used as the lower quantile Value_down, and the scattering amplitude value corresponding to the second percentile (such as 98%) is used as the upper quantile Value_up. The scattering amplitude value between the lower quantile Value_down and the upper quantile Value_up is a valid scattering amplitude value, and the scattering amplitude value less than the lower quantile Value_down or greater than the upper quantile Value_up is an invalid scattering amplitude value.

[0082] For the above-mentioned invalid scattering amplitude values, the lower quantile Value_down is used to replace the scattering amplitude values ​​less than the lower quantile Value_down, that is, the compensated SAR image data Tiffdata_dB_inc less than Value_down is assigned to Value_down; and the upper quantile Value_up is used to replace the scattering amplitude values ​​greater than the upper quantile Value_up, that is, the compensated SAR image data Tiffdata_dB_inc greater than Value_up is assigned to Value_up.

[0083] In summary, the aforementioned steps S104 to S108 are the core steps of the embodiment of the present invention. The embodiment of the present invention has at least the following features:

[0084] (I) This technology effectively solves the problem of poor display effect of wide-band SAR images in ocean scenes by performing three processing steps: logarithmic quantization, incident angle increment compensation, and percentage linear stretching on the original quantitative data of the image. Specifically, it is ① effectively solving the problem of bright near-end and dark far-end of wide-band SAR images in ocean scenes; ② effectively solving the problem of all-black or all-white images caused by strong scattering targets in the ocean.

[0085] (ii) See Figure 2 The following is a processing result diagram based on the comparison of sential1A-EM mode images (500km width). (a) is the original SAR image. Without any stretching, the original image is displayed in black. (b) is the result of traditional SAR image enhancement processing. The results show that some details can be seen, but due to the small incident angle at the near end on the left, the scattering intensity is large and the display is bright, resulting in the inability to clearly display the details at the far end on the right. (c) is the image enhancement processing result proposed in an embodiment of the present invention, which eliminates the problem of bright near end and dark far end, and the overall image is clear and rich in details.

[0086] Based on the above-mentioned embodiments, the present invention provides a SAR image enhancement display processing device, see Figure 3 The structure diagram of a SAR image enhancement display processing device shown in FIG. 1 mainly includes the following parts:

[0087] The data acquisition module 302 is used to acquire the SAR image data to be processed and its corresponding incident angle array;

[0088] A logarithmic quantization module 304 is used to perform logarithmic quantization processing on the SAR image data to be processed to obtain quantized SAR image data;

[0089] The gain compensation module 306 is used to perform incident angle gain compensation processing on the quantized SAR image data based on the incident angle array to obtain compensated SAR image data;

[0090] The nonlinear stretching module 308 is used to perform percentage nonlinear stretching processing on the compensated SAR image data to obtain enhanced and displayed target SAR image data.

[0091] The above-mentioned device provided by the embodiment of the present invention effectively solves the problem of poor display effect of wide-width SAR images in ocean scenes by performing three processing processes of logarithmic quantization, incident angle gain compensation, and percentage linear stretching on the SAR image data to be processed.

[0092] In one implementation, the incident angle array includes incident angle data corresponding to each pixel point at each distance inward in the SAR image data to be processed; the gain compensation module 306 is further used to:

[0093] For each pixel point at each distance inward in the SAR image data to be processed, according to the threshold interval covered by the incident angle data corresponding to the pixel point, the target electromagnetic scattering model corresponding to the pixel point is determined from the candidate electromagnetic scattering models, so as to generate an incident angle gain compensation value based on the incident angle data corresponding to the pixel point through the target electromagnetic scattering model;

[0094] The incident angle gain compensation value is used to perform incident angle gain compensation processing on the SAR image data to be processed, so as to obtain compensated SAR image data.

[0095] In one implementation, the candidate electromagnetic scattering models include: a perturbation electromagnetic scattering model, a Kirchhoff electromagnetic scattering model, and a dual-scale electromagnetic scattering model; the gain compensation module 306 is further used to:

[0096] If the incident angle data corresponding to the pixel point is within the medium incident angle threshold interval, the perturbation electromagnetic scattering model is used as the target electromagnetic scattering model;

[0097] Alternatively, if the incident angle data corresponding to the pixel point is within the small incident angle threshold interval, the Kirchhoff electromagnetic scattering model is used as the target electromagnetic scattering model;

[0098] Alternatively, if the range of the incident angle data corresponding to the pixel point covers both the medium incident angle threshold interval and the small incident angle threshold interval, the dual-scale electromagnetic scattering model is used as the target electromagnetic scattering model.

[0099] In one implementation, the gain compensation module 306 is further configured to:

[0100] For the SAR image data to be processed, the difference between the incident angle data and the incident angle gain compensation value is calculated range-wise and pixel-wise to obtain the compensated SAR image data.

[0101] In one embodiment, the nonlinear stretching module 308 is further configured to:

[0102] Sorting the scattering amplitude values ​​corresponding to each pixel point in the compensated SAR image data to determine the scattering amplitude values ​​corresponding to two preset percentile points based on the sorting result;

[0103] Based on the scattering amplitude value corresponding to the preset percentile point, the effective scattering amplitude value and the invalid scattering amplitude value are determined, and the invalid scattering amplitude value is adjusted to achieve percentage nonlinear stretching processing to obtain the target SAR image data after enhanced display.

[0104] In one embodiment, the preset percentile includes a first percentile and a second percentile, the first percentile is less than the second percentile, and the sum of the first percentile and the second percentile is 100%; the nonlinear stretching module 308 is further used for:

[0105] The scattering amplitude value corresponding to the first percentile is taken as the lower quantile, and the scattering amplitude value corresponding to the second percentile is taken as the upper quantile;

[0106] Among them, the scattering amplitude value between the lower quantile and the upper quantile is a valid scattering amplitude value, and the scattering amplitude value less than the lower quantile or greater than the upper quantile is an invalid scattering amplitude value.

[0107] In one embodiment, the nonlinear stretching module 308 is further configured to:

[0108] Scattering amplitude values ​​less than the lower quantile are replaced with the lower quantile; and scattering amplitude values ​​greater than the upper quantile are replaced with the upper quantile.

[0109] The device provided in the embodiment of the present invention has the same implementation principle and technical effects as those of the aforementioned method embodiment. For the sake of brief description, for matters not mentioned in the device embodiment, reference may be made to the corresponding contents in the aforementioned method embodiment.

[0110] An embodiment of the present invention provides an electronic device. Specifically, the electronic device includes a processor and a storage device. The storage device stores a computer program, and when the computer program is executed by the processor, it executes the method described in any one of the above-mentioned implementation methods.

[0111] Figure 4 A structural diagram of an electronic device provided in an embodiment of the present invention, the electronic device 100 includes: a processor 40, a memory 41, a bus 42 and a communication interface 43, wherein the processor 40, the communication interface 43 and the memory 41 are connected via the bus 42; the processor 40 is used to execute an executable module stored in the memory 41, such as a computer program.

[0112] The memory 41 may include a high-speed random access memory (RAM), and may also include a non-volatile memory, such as at least one disk memory. The communication connection between the system network element and at least one other network element is realized through at least one communication interface 43 (which may be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. may be used.

[0113] The bus 42 may be an ISA bus, a PCI bus, or an EISA bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 4 Only one bidirectional arrow is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0114] Among them, the memory 41 is used to store programs, and the processor 40 executes the program after receiving the execution instruction. The method executed by the device for flow process definition disclosed in any embodiment of the above-mentioned embodiment of the present invention can be applied to the processor 40 or implemented by the processor 40.

[0115] The processor 40 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the hardware integrated logic circuit or software instructions in the processor 40. The above processor 40 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present invention can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor. The steps of the method disclosed in the embodiments of the present invention can be directly embodied as a hardware decoding processor to execute, or can be executed by a combination of hardware and software modules in the decoding processor. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 41, and the processor 40 reads the information in the memory 41 and completes the steps of the above method in combination with its hardware.

[0116] The computer program product of the readable storage medium provided in the embodiment of the present invention includes a computer-readable storage medium storing program code, and the instructions included in the program code can be used to execute the methods described in the previous method embodiments. The specific implementation can be referred to the previous method embodiments, which will not be repeated here.

[0117] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0118] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A SAR image enhancement display processing method, characterized in that: include: Obtain the SAR image data to be processed and its corresponding incident angle array; Performing logarithmic quantization processing on the SAR image data to be processed to obtain quantized SAR image data; Based on the incident angle array, performing incident angle gain compensation processing on the quantized SAR image data to obtain compensated SAR image data; Performing percentage nonlinear stretching processing on the compensated SAR image data to obtain enhanced and displayed target SAR image data; The incident angle array includes incident angle data corresponding to each pixel point at each distance inward in the SAR image data to be processed; Based on the incident angle array, the step of performing incident angle gain compensation processing on the quantized SAR image data to obtain compensated SAR image data includes: for each pixel point at each distance inward in the SAR image data to be processed, according to the threshold interval covered by the incident angle data corresponding to the pixel point, determining the target electromagnetic scattering model corresponding to the pixel point from the candidate electromagnetic scattering models, so as to generate an incident angle gain compensation value based on the incident angle data corresponding to the pixel point through the target electromagnetic scattering model; using the incident angle gain compensation value, performing incident angle gain compensation processing on the SAR image data to be processed to obtain compensated SAR image data; The step of performing incident angle gain compensation processing on the SAR image data to be processed by using the incident angle gain compensation value to obtain compensated SAR image data comprises: for the SAR image data to be processed, calculating the difference between the incident angle data and the incident angle gain compensation value in the range direction and pixel by pixel to obtain the compensated SAR image data; The step of performing percentage nonlinear stretching processing on the compensated SAR image data to obtain the target SAR image data after enhanced display comprises: sorting the scattering amplitude values ​​corresponding to each pixel point in the compensated SAR image data to determine the scattering amplitude values ​​corresponding to two preset percentile points based on the sorting result; determining the effective scattering amplitude value and the invalid scattering amplitude value based on the scattering amplitude values ​​corresponding to the preset percentile points, and adjusting the invalid scattering amplitude value to achieve percentage nonlinear stretching processing to obtain the target SAR image data after enhanced display.

2. The SAR image enhancement display processing method according to claim 1, characterized in that: The candidate electromagnetic scattering models include: perturbation electromagnetic scattering model, Kirchhoff electromagnetic scattering model, and dual-scale electromagnetic scattering model; The step of determining a target electromagnetic scattering model corresponding to the pixel point from candidate electromagnetic scattering models according to a threshold range covered by the incident angle data corresponding to the pixel point comprises: If the incident angle data corresponding to the pixel point is within the medium incident angle threshold interval, the perturbation electromagnetic scattering model is used as the target electromagnetic scattering model; Alternatively, if the incident angle data corresponding to the pixel point is within a small incident angle threshold interval, the Kirchhoff electromagnetic scattering model is used as a target electromagnetic scattering model; Alternatively, if the range of the incident angle data corresponding to the pixel point covers both the medium incident angle threshold interval and the small incident angle threshold interval, the dual-scale electromagnetic scattering model is used as the target electromagnetic scattering model.

3. The SAR image enhancement display processing method according to claim 1, characterized in that: The preset percentile includes a first percentile and a second percentile, the first percentile is less than the second percentile, and the sum of the first percentile and the second percentile is 100%; The step of determining a valid scattering amplitude value and an invalid scattering amplitude value based on the scattering amplitude value corresponding to the preset percentile point comprises: The scattering amplitude value corresponding to the first percentile is used as the lower quantile, and the scattering amplitude value corresponding to the second percentile is used as the upper quantile; The scattering amplitude value between the lower quantile and the upper quantile is a valid scattering amplitude value, and the scattering amplitude value less than the lower quantile or greater than the upper quantile is an invalid scattering amplitude value.

4. The SAR image enhancement display processing method according to claim 3, characterized in that: The step of adjusting the invalid scattering amplitude value comprises: The scattering amplitude values ​​smaller than the lower quantile are replaced with the lower quantile; and the scattering amplitude values ​​larger than the upper quantile are replaced with the upper quantile.

5. A SAR image enhancement display processing device, characterized in that: include: A data acquisition module is used to acquire the SAR image data to be processed and its corresponding incident angle array; A logarithmic quantization module is used to perform logarithmic quantization on the SAR image data to be processed to obtain quantized SAR image data; A gain compensation module, used for performing incident angle gain compensation processing on the quantized SAR image data based on the incident angle array to obtain compensated SAR image data; A nonlinear stretching module, used for performing a percentage nonlinear stretching process on the compensated SAR image data to obtain target SAR image data after enhanced display; The incident angle array includes incident angle data corresponding to each pixel point at each distance inward in the SAR image data to be processed; the gain compensation module is specifically used to: for each pixel point at each distance inward in the SAR image data to be processed, determine the target electromagnetic scattering model corresponding to the pixel point from the candidate electromagnetic scattering models according to the threshold interval covered by the incident angle data corresponding to the pixel point, so as to generate an incident angle gain compensation value based on the incident angle data corresponding to the pixel point through the target electromagnetic scattering model; and perform incident angle gain compensation processing on the SAR image data to be processed using the incident angle gain compensation value to obtain compensated SAR image data; The gain compensation module is specifically used to: for the SAR image data to be processed, calculate the difference between the incident angle data and the incident angle gain compensation value in a range-by-range and pixel-by-pixel manner to obtain compensated SAR image data; The nonlinear stretching module is specifically used to: sort the scattering amplitude values ​​corresponding to each pixel point in the compensated SAR image data, so as to determine the scattering amplitude values ​​corresponding to two preset percentile points based on the sorting result; Based on the scattering amplitude value corresponding to the preset percentile, the effective scattering amplitude value and the invalid scattering amplitude value are determined, and the invalid scattering amplitude value is adjusted to achieve percentage nonlinear stretching processing to obtain the target SAR image data after enhanced display.

6. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the memory stores computer executable instructions that can be executed by the processor, and the processor executes the computer executable instructions to implement the method according to any one of claims 1 to 4.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions. When the computer-executable instructions are called and executed by a processor, the computer-executable instructions prompt the processor to implement the method according to any one of claims 1 to 4.

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