Image domain to RCS domain transformation method, device, computing device and storage medium

Abstract

The present invention provides a method, device, computing device and storage medium for transforming from an image domain to an RCS domain, wherein the method comprises: determining the angle range corresponding to the transformation to the RCS domain; obtaining a two-dimensional target image to be transformed according to the angle range; determining each observation angle within the angle range according to a preset angle step; for each observation angle, projecting the two-dimensional target image according to a preset distance step using RADON transformation to obtain a one-dimensional distance image corresponding to each observation angle; performing a fast Fourier transform on each one-dimensional distance image to obtain frequency data corresponding to each observation angle. This solution can be applicable to a larger angle range while ensuring the calculation accuracy, and can improve the transformation speed.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of data processing technology, and in particular to a method, apparatus, computing device and storage medium for transforming from an image domain to an RCS domain. Background Art

[0002] When analyzing and evaluating the local scattering characteristics of stealth targets or stealth components, the method often used is to process the two-dimensional scattering characteristic image of the target and then inverse transform it to obtain the scattering response data in the RCS (Radar Cross Section) domain. Since the two-dimensional scattering characteristic image generally contains two dimensions, horizontal and vertical, and belongs to the rectangular coordinate system, and the data obtained after the local scattering characteristic analysis generally contains two dimensions, angle and frequency, and belongs to the polar coordinate system. In essence, the processing method is to find a transformation algorithm from the image domain of horizontal and vertical rectangular coordinates to the RCS domain of angle-frequency polar coordinates.

[0003] At present, the commonly used inverse transformation methods are the two-dimensional fast Fourier transform (FFT) inverse transformation and the direct scattering center synthesis algorithm. The calculation speed of the two-dimensional FFT inverse transformation is fast, but it can only be used for small-angle imaging data, generally not exceeding 10 degrees. Since the linear conditions of the two-dimensional FFT inverse transformation need to be met, the fan-shaped ring domain data needs to be approximately equivalent to square (or rectangular) local transformation data, so it is only applicable to small-angle imaging data. When the angle is too large, the accuracy of the inverse transformation method will be greatly reduced. The direct scattering center synthesis algorithm is based on the principle of scattering center synthesis. It regards each pixel in the two-dimensional image as a complex scattering source, and uses the scattering center synthesis formula to calculate each pixel point and then superimpose and sum to obtain the corresponding RCS domain scattering response data. Because this method is directly based on the scattering principle, the calculation result accuracy is the highest among the methods of processing the two-dimensional image and then inverting it, and the applicable angle range is also the widest. However, since two-dimensional images have a large number of pixels, such as 401*401, 801*801 or more, this method takes a long time to calculate and is not suitable for scenarios that require real-time processing and analysis.

[0004] Based on this, there is an urgent need to provide a fast conversion method that can be applied to a larger angle range. Summary of the invention

[0005] The embodiments of the present invention provide a method, apparatus, computing device and storage medium for transforming from an image domain to an RCS domain, which can be applicable to a larger angle range while ensuring the calculation accuracy and can improve the transformation speed.

[0006] In a first aspect, an embodiment of the present invention provides a method for transforming from an image domain to an RCS domain, comprising:

[0007] Determine the angle range corresponding to the transformation into the RCS domain;

[0008] According to the angle range, acquiring a two-dimensional target image to be transformed;

[0009] Determine each observation angle within the angle range according to a preset angle step;

[0010] For each observation angle, the two-dimensional target image is projected according to a preset distance step by using RADON transformation to obtain a one-dimensional range image corresponding to each observation angle;

[0011] Perform fast Fourier transform on each one-dimensional range image to obtain frequency data corresponding to each observation angle.

[0012] Preferably, acquiring the two-dimensional target image to be transformed according to the angle range includes:

[0013] Using a radar to measure the RCS of a target, the angular domain range of the RCS measurement covers the angular range;

[0014] Acquire corresponding data within the angle range from the RCS measured data;

[0015] The acquired corresponding data within the angle range is converted into the two-dimensional target image.

[0016] Preferably, the projecting the two-dimensional target images respectively according to a preset distance step using RADON transformation includes:

[0017] According to a current observation angle in each observation angle, determining a plurality of projection lines perpendicular to the current observation angle according to the preset distance step;

[0018] Based on the vertical distance between the coordinate origin of the two-dimensional target image and each projection line, performing RADON transformation on each pixel point in the two-dimensional target image to obtain a projection result of the two-dimensional target image vertically projected onto each projection line;

[0019] The projection results corresponding to the multiple projection lines are determined as a one-dimensional range image corresponding to the current observation angle.

[0020] Preferably, performing RADON transformation on each pixel in the two-dimensional target image includes:

[0021] The following formula is used to perform RADON transformation on each pixel in the two-dimensional target image:

[0022]

[0023] Wherein, p is the vertical distance between the coordinate origin and the projection line of the two-dimensional target image, φ is the current observation angle, g(rcosθ,rsinθ) is the two-dimensional scattering function of the two-dimensional target image, r is the polar diameter of the pixel point in the polar coordinate system, θ is the angle of the pixel point in the polar coordinate system, δ() is the Dirac function, and R(p,φ) is the one-dimensional range image of the current observation angle.

[0024] Preferably, performing a fast Fourier transform on each one-dimensional range image comprises:

[0025] Perform a fast Fourier transform on each one-dimensional range image according to the following formula:

[0026]

[0027] Among them, G(ρ,φ) is the frequency data corresponding to the observation angle, R(p,φ) is the one-dimensional distance image, p is the vertical distance between the projection line and the coordinate origin, φ is the current observation angle, is the wave number, f is the frequency, c is the speed of light, and -j represents the conjugate complex number.

[0028] Preferably, before projecting the two-dimensional target images respectively, the method further comprises:

[0029] The constructed regional gate function is used to perform at least one of corner attenuation processing, mouse drawing area processing and eraser processing on the two-dimensional target image, and the processed two-dimensional target image is used to perform the projection of the two-dimensional target image.

[0030] Preferably, after performing fast Fourier transform on each one-dimensional range image and before obtaining frequency data corresponding to each observation angle, the method further includes:

[0031] Determine the amount of zero padding to be performed on the one-dimensional range image and the type of window function to be used when performing a fast Fourier transform;

[0032] Determining an error correction factor according to the zero padding amount and the window function type;

[0033] The product of the initial frequency data obtained after the fast Fourier transform and the error correction factor is determined as the frequency data corresponding to the observation angle.

[0034] In a second aspect, an embodiment of the present invention further provides a device for transforming from an image domain to an RCS domain, comprising:

[0035] An angle range determination unit, used to determine the angle range corresponding to the transformation into the RCS domain;

[0036] A two-dimensional target image acquisition unit, used for acquiring a two-dimensional target image to be transformed according to the angle range;

[0037] An observation angle determination unit, used to determine each observation angle within the angle range according to a preset angle step;

[0038] A one-dimensional range image projection unit is used to project the two-dimensional target image according to a preset distance step size using RADON transformation for each observation angle, so as to obtain a one-dimensional range image corresponding to each observation angle;

[0039] The Fourier transform unit is used to perform fast Fourier transform on each one-dimensional range image to obtain frequency data corresponding to each observation angle.

[0040] In a third aspect, an embodiment of the present invention further provides a computing device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method described in any embodiment of this specification is implemented.

[0041] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, enables the computer to execute the method described in any embodiment of this specification.

[0042] The embodiment of the present invention provides a method, device, computing device and storage medium for transforming from an image domain to an RCS domain. The two-dimensional target image is projected using the RADON transform to obtain a one-dimensional range image. It can be seen that the image subjected to the fast Fourier transform is one-dimensional. Since it does not involve the approximate equivalence of the fan-shaped ring domain data and the rectangular local data in the two-dimensional fast Fourier transform, there is no need to consider the angular range of the two-dimensional target image. Therefore, this solution is applicable to a larger angular range, and the calculation accuracy of the fast Fourier transform of the one-dimensional image is greatly increased compared to the fast Fourier transform of the two-dimensional image. In addition, since the fast Fourier transform is used to obtain the frequency data corresponding to each observation angle, the calculation time can be shortened and the transformation speed can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 is a flow chart of a method for transforming from an image domain to an RCS domain provided by an embodiment of the present invention;

[0045] Figure 2 This is a frequency domain result diagram after being processed by a direct scattering center synthesis algorithm provided by an embodiment of the present invention;

[0046] Figure 3 This is an angular domain result diagram after being processed by a direct scattering center synthesis algorithm provided by an embodiment of the present invention;

[0047] Figure 4 It is a frequency domain result diagram after being processed by a method for transforming from an image domain to an RCS domain provided by an embodiment of the present invention;

[0048] Figure 5 is an angle domain result diagram after being processed by a method for transforming from an image domain to an RCS domain provided by an embodiment of the present invention;

[0049] Figure 6 is a hardware architecture diagram of a computing device provided by an embodiment of the present invention;

[0050] Figure 7 is a structural diagram of a device for transforming from an image domain to an RCS domain provided by an embodiment of the present invention;

[0051] Figure 8 is a structural diagram of another image domain to RCS domain transformation device provided by an embodiment of the present invention;

[0052] Fig. 9 This is a structural diagram of another image domain to RCS domain transformation device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0054] As mentioned above, in the existing inverse transformation methods, the two-dimensional FFT inverse transformation is only applicable to small-angle imaging data, and the direct scattering center synthesis algorithm takes too long. Therefore, the use of the self-focusing algorithm is considered to make the angle range applicable to this scheme wider while ensuring the calculation accuracy. Therefore, for each observation angle, the RADON transformation is used to project the two-dimensional target image to obtain a one-dimensional distance image corresponding to each observation angle. And in order to shorten the operation time, when calculating the frequency response, the obtained one-dimensional distance image is subjected to a fast Fourier transform, and the frequency data corresponding to each observation angle can be obtained, that is, the angle-frequency RCS scattering response data. Therefore, this scheme is applicable to a wider angle range, and the calculation accuracy is guaranteed, while also greatly shortening the operation time.

[0055] The specific implementation of the above concept is described below.

[0056] Please refer to Figure 1 , an embodiment of the present invention provides a method for transforming from an image domain to an RCS domain, the method comprising:

[0057] Step 100, determining the angle range corresponding to the transformation into the RCS domain;

[0058] Step 102, acquiring a two-dimensional target image to be transformed according to the angle range;

[0059] Step 104, determining each observation angle within the angle range according to a preset angle step;

[0060] Step 106, for each observation angle, project the two-dimensional target image according to a preset distance step using RADON transformation to obtain a one-dimensional range image corresponding to each observation angle;

[0061] Step 108, performing a fast Fourier transform on each one-dimensional range image to obtain frequency data corresponding to each observation angle.

[0062] In the embodiment of the present invention, the two-dimensional target image is projected using the RADON transform, and a one-dimensional range image is obtained. It can be seen that the image subjected to the fast Fourier transform is one-dimensional. Since the approximate equivalence between the sector ring data and the rectangular local data in the two-dimensional fast Fourier transform is not involved, there is no need to consider the angle range of the two-dimensional target image. Therefore, this solution is applicable to a larger angle range, and the calculation accuracy of the fast Fourier transform of the one-dimensional image is greatly increased relative to the fast Fourier transform of the two-dimensional image. In addition, since the fast Fourier transform is used to obtain the frequency data corresponding to each observation angle, the calculation time can be shortened and the transformation speed can be improved.

[0063] Described below Figure 1 How the various steps are performed.

[0064] First, with respect to step 100, the angle range corresponding to the transformation into the RCS domain is determined.

[0065] In the embodiment of the present invention, the swept frequency RCS data obtained by RCS measurement in a microwave darkroom is mainly used. During the measurement, the target rotates a certain angle along with the turntable, and the obtained RCS measurement data corresponds to the data of the target within this rotation angle range. Therefore, it is first necessary to determine the angle range of the target rotation of interest when analyzing and evaluating the local scattering characteristics of the target, that is, the angle range corresponding to the angle-frequency RCS scattering response data after the two-dimensional target image is transformed from the image domain to the RCS domain.

[0066] Then, for step 102, a two-dimensional target image to be transformed is acquired according to the angle range.

[0067] In order to ensure that the angle-frequency RCS scattering response data obtained after transformation into the RCS domain includes the angle range of interest to the target, it is necessary to obtain the two-dimensional target image to be transformed according to the angle range corresponding to the transformation into the RCS domain determined in step 100.

[0068] The specific method is to use a radar to measure the RCS of the target, and the angular range of the RCS measurement covers the angle range; obtain corresponding data within the angle range from the RCS measurement data; and convert the obtained corresponding data within the angle range into the two-dimensional target image.

[0069] For example, if the angle range of interest is ±15 degrees, then when using radar to measure the RCS of a target, the measured angular range should exceed ±15 degrees, such as ±80 degrees. The RCS data corresponding to ±15 degrees is obtained from the measured RCS data of ±80 degrees, and converted into a two-dimensional target image. At this time, the imaging angle of the two-dimensional target image is ±15 degrees. It can be used as the two-dimensional target image to be transformed, and the transformed angle-frequency RCS scattering response data contains the target RCS data of ±15 degrees.

[0070] Next, for step 104, each observation angle within the angle range is determined according to the preset angle step.

[0071] In the embodiment of the present invention, it is necessary to preset an angle step according to actual needs. The smaller the angle step, the finer the corresponding angle in the transformed angle-frequency RCS scattering response data. According to the preset angle step, several observation angles are determined from the angle range determined in step 100.

[0072] It should be noted that the observation angle may be within the imaging angle of the two-dimensional target image, or may exceed the imaging angle, that is, the angular domain may be extrapolated. It is understood that the angle range determined in step 100, that is, the angle range of interest may be smaller than or larger than the imaging angle of the two-dimensional target image. In the embodiment of the present invention, the angle range is equal to the imaging angle of the two-dimensional target image.

[0073] Next, for step 106, for each observation angle, the two-dimensional target image is projected according to a preset distance step using RADON transformation to obtain a one-dimensional range image corresponding to each observation angle.

[0074] Since the two-dimensional target image obtained in step 102 may contain other objects, or it is desired to analyze the scattering characteristics of a local area of ​​the target, before projecting the two-dimensional target image separately, the constructed regional gate function can be used to perform at least one of corner attenuation processing, mouse drawing area processing and eraser processing on the two-dimensional target image, and the processed two-dimensional target image is used to perform the projection of the two-dimensional target image separately.

[0075] It can be understood that the pixel values ​​in the two-dimensional target image are modified by using the constructed regional gate function to remove noise, obtain the desired target local image, and then project the processed two-dimensional target image.

[0076] It is particularly important to note that the essence of the conversion from the image domain to the RCS domain is the high-frequency local scattering mechanism of the radar target, based on the scattering center (source) synthesis formula, as shown below:

[0077]

[0078] Among them, G(ρ,φ) is the frequency data corresponding to the observation angle, φ is the observation angle, is the wave number, f is the frequency, c is the speed of light, -j represents the conjugate complex number, g(rcosθ,rsinθ) is the two-dimensional scattering function of the two-dimensional target image, r is the polar diameter of the pixel in the polar coordinate system, and θ is the angle of the pixel in the polar coordinate system.

[0079] By deforming the above scattering center (source) synthesis formula, the transformation formula from the image domain to the RCS domain provided by the embodiment of the present invention can be obtained as follows:

[0080]

[0081] Among them, G(ρ,φ) is the frequency data corresponding to the observation angle, p is the vertical distance between the projection line and the coordinate origin, φ is the current observation angle, is the wave number, f is the frequency, c is the speed of light, -j represents the conjugate complex number, g(rcosθ,rsinθ) is the two-dimensional scattering function of the two-dimensional target image, r is the polar diameter of the pixel in the polar coordinate system, θ is the angle of the pixel in the polar coordinate system, and δ() is the Dirac function.

[0082] It can be seen from the above two formulas, namely, the transformation formula from the image domain to the RCS domain and the scattering center (source) synthesis formula provided in the embodiment of the present invention, that the transformation formula from the image domain to the RCS domain provided in the embodiment of the present invention is a deformation formula guided by the scattering center (source) synthesis formula.

[0083] The direct scattering center synthesis algorithm in the prior art directly uses the scattering center (source) synthesis formula to calculate the angle-frequency scattering response. It is an algorithm with the highest calculation accuracy, but the calculation time is relatively long. The image domain to RCS domain transformation method provided in this embodiment is guided by the principle of local scattering center synthesis and uses RADON transformation and FFT algorithm for transformation. Compared with the transformation method in the prior art, it not only ensures a wide adaptation angle range and high accuracy, but also reduces the calculation time.

[0084] It can be seen that the transformation formula from the image domain to the RCS domain provided in the above embodiment of the present invention can be calculated in two steps, namely, RADON transformation and fast Fourier transformation.

[0085] Specifically, in one embodiment of the present invention, the processed two-dimensional target image can be projected at least through the following steps:

[0086] S1, according to a current observation angle in each observation angle, determining a plurality of projection lines perpendicular to the current observation angle according to the preset distance step;

[0087] S2, based on the vertical distance between the coordinate origin of the two-dimensional target image and each projection line, performing RADON transformation on each pixel point in the two-dimensional target image to obtain a projection result of vertically projecting the two-dimensional target image onto each projection line;

[0088] S3, determining the projection results corresponding to the multiple projection lines as a one-dimensional range image corresponding to the current observation angle.

[0089] In the embodiment of the present invention, the coordinate origin of the two-dimensional target image can be any point in the image. In this embodiment, the pixel point at the lower left corner of the image is taken as the coordinate origin and the pole transformed into polar coordinates. Then, multiple projection lines perpendicular to the current observation angle can be expressed as:

[0090] L(ρ,θ)={(ρ,φ):ρcos(θ-φ)=p}

[0091] Among them, L(ρ,θ) is the projection line, p is the vertical distance between the projection line and the pole, φ is the current observation angle, is the wave number, f is the frequency, c is the speed of light, and θ is the angle of the pixel in the polar coordinate system.

[0092] In the embodiment of the present invention, the following formula is used to perform RADON transformation on each pixel in the two-dimensional target image:

[0093]

[0094] Wherein, p is the vertical distance between the coordinate origin and the projection line of the two-dimensional target image, φ is the current observation angle, g(rcosθ,rsinθ) is the two-dimensional scattering function of the two-dimensional target image, r is the polar diameter of the pixel point in the polar coordinate system, θ is the angle of the pixel point in the polar coordinate system, δ() is the Dirac function, and R(p,φ) is the one-dimensional range image of the current observation angle.

[0095] In the embodiment of the present invention, the above formula can be understood as that at the current observation angle, each pixel point in the two-dimensional target image is projected on each projection line, that is, integration is performed on each projection line to obtain a one-dimensional range image corresponding to the current observation angle. Similarly, by projecting each observation angle, a one-dimensional range image corresponding to each observation angle can be obtained.

[0096] Finally, for step 108, a fast Fourier transform is performed on each one-dimensional range image to obtain frequency data corresponding to each observation angle.

[0097] It can be seen from the transformation formula from the image domain to the RCS domain provided by the embodiment of the present invention that after using the RADON transformation, each one-dimensional range image can be fast Fourier transformed according to the following formula:

[0098]

[0099] Among them, G(ρ,φ) is the frequency data corresponding to the observation angle, R(p,φ) is the one-dimensional distance image, p is the vertical distance between the projection line and the coordinate origin, φ is the current observation angle, is the wave number, f is the frequency, c is the speed of light, and -j represents the conjugate complex number.

[0100] It can be seen that the above formula is obviously a Fourier transform pair, which can be quickly implemented using the fast Fourier transform algorithm (FFT). Therefore, performing a fast Fourier transform on each one-dimensional range image and calculating the frequency data corresponding to each observation angle can greatly improve the calculation speed.

[0101] Furthermore, in the embodiment of the present invention, after performing fast Fourier transform on each one-dimensional range image, before obtaining frequency data corresponding to each observation angle, an error correction algorithm is also used. Different from the traditional method of constructing standardized data, the deviation caused by the windowing and zero-filling operations in the FFT algorithm is directly analyzed and calculated. Compared with the traditional method of constructing standardized data, which requires re-performing the operation process, the operation speed is also greatly improved.

[0102] Specifically, the method is to determine the number of zero padding performed on the one-dimensional range image and the type of window function used when performing fast Fourier transform; determine the error correction factor according to the number of zero padding and the type of window function; and determine the product of the initial frequency data obtained after the fast Fourier transform and the error correction factor as the frequency data corresponding to the observation angle.

[0103] For example, when using the FFT algorithm to calculate the frequency response data at each observation angle, the number of data points after the FFT algorithm fills in zeros on the observation angle data and the number of original data points are calculated, and the ratio of the number of data points after zero filling to the original number of data points is determined as the zero-filling error correction factor; according to the type of window function used by the FFT algorithm on the observation angle data, the error of each window function used is determined, and the windowing error correction factor is determined according to the number of window functions used by the FFT algorithm; the product of the initial frequency data obtained after the fast Fourier transform, the zero-filling error correction factor and the windowing error correction factor is determined as the frequency data corresponding to the observation angle.

[0104] The frequency response data at each observation angle are subjected to the same error correction algorithm to obtain the final angle-frequency RCS scattering response data, completing the transformation of the two-dimensional target image from the image domain to the RCS domain.

[0105] like Figure 2 , Figure 3 As shown, the processing results of two two-dimensional target images using the direct scattering center synthesis algorithm are shown. Figure 4 , Figure 5 , is the processing result of the transformation algorithm provided in this embodiment on the two two-dimensional target images that are the same as the direct scattering center synthesis algorithm. The two two-dimensional target images are respectively a two-dimensional target image of a double ball and a two-dimensional target image of a single ball, and the angle range is 85 degrees to 95 degrees, and the frequency range is 9.5 GHZ to 10.5 GHZ.

[0106] like Figure 2 As shown, after the direct scattering center synthesis algorithm is processed, the solid line represents the RCS value corresponding to each frequency of the double sphere when the center angle is 90 degrees, and the dotted line represents the RCS value corresponding to each frequency of the single sphere when the center angle is 90 degrees. Figure 3The solid line in the figure represents the RCS value corresponding to each angle of the double sphere when the center frequency is 10 GHZ, and the dotted line represents the RCS value corresponding to each angle of the single sphere when the center frequency is 10 GHZ.

[0107] Similarly, Figure 4 It represents the RCS value corresponding to each frequency when the double sphere and the single sphere are at the center angle of 90 degrees after being processed by the transformation algorithm provided by this embodiment. The solid line represents the double sphere and the dotted line represents the single sphere. Figure 5 It represents the RCS value corresponding to each angle of the double sphere and the single sphere at the center frequency of 10 GHZ after being processed by the transformation algorithm provided in this embodiment.

[0108] Compare Figure 2 and Figure 4 It can be seen from the solid and dotted lines in that when the center angle is 1, the RCS values ​​corresponding to each frequency of the double sphere and the single sphere obtained by the direct scattering center synthesis algorithm and the transformation algorithm provided in this embodiment are very small. Figure 3 and Figure 5 It can be seen from the solid and dotted lines in that, at the center frequency, the RCS values ​​corresponding to each angle of the double sphere and the single sphere obtained by the direct scattering center synthesis algorithm and the transformation algorithm provided in this embodiment are also very small. Therefore, it can be proved that the calculation accuracy of the transformation algorithm provided in this embodiment is relatively high.

[0109] In terms of calculation time, the calculation time of the two-dimensional FFT inverse transform, the direct scattering center synthesis algorithm and the transformation algorithm provided in this embodiment is 30 seconds, 15 minutes and 186 seconds respectively when the same device processes the same two-dimensional target image. Therefore, the transformation algorithm provided in this embodiment not only ensures the calculation accuracy, but also reduces the calculation time.

[0110] like Figure 6 , Figure 7 As shown, an embodiment of the present invention provides a device for transforming an image domain into an RCS domain. The device embodiment can be implemented by software, or by hardware or a combination of software and hardware. From the hardware level, Figure 6 As shown, a hardware architecture diagram of a computing device where an image domain to RCS domain conversion device provided by an embodiment of the present invention is located, except Figure 6 In addition to the processor, memory, network interface, and non-volatile memory shown in the figure, the computing device in which the device is located in the embodiment may also generally include other hardware, such as a forwarding chip responsible for processing messages, etc. Taking software implementation as an example, Figure 7 As shown, as a device in a logical sense, the CPU of the computing device in which it is located reads the corresponding computer program in the non-volatile memory into the internal memory and runs it. This embodiment provides a device for transforming an image domain into an RCS domain, including:

[0111] An angle range determining unit 701, used to determine the angle range corresponding to the transformation into the RCS domain;

[0112] A two-dimensional target image acquisition unit 702, configured to acquire a two-dimensional target image to be transformed according to the angle range;

[0113] An observation angle determination unit 703 is used to determine each observation angle within the angle range according to a preset angle step;

[0114] A one-dimensional range image projection unit 704 is used to project the two-dimensional target image according to a preset distance step size using RADON transformation for each observation angle to obtain a one-dimensional range image corresponding to each observation angle;

[0115] The Fourier transform unit 705 is used to perform fast Fourier transform on each one-dimensional range image to obtain frequency data corresponding to each observation angle.

[0116] In one embodiment of the present invention, the two-dimensional target image acquisition unit 702, when executing the step of acquiring the two-dimensional target image to be transformed according to the angle range, is specifically used to perform RCS measurement on the target using a radar, and the angular range of the RCS measurement covers the angle range; obtain corresponding data within the angle range from the RCS measurement data; and convert the corresponding data within the angle range into the two-dimensional target image.

[0117] In one embodiment of the present invention, the one-dimensional range image projection unit 704, when executing the RADON transformation to project the two-dimensional target image respectively according to the preset distance step, is specifically used to determine a plurality of projection lines perpendicular to the current observation angle according to the preset distance step in each observation angle; based on the vertical distance between the coordinate origin of the two-dimensional target image and each projection line, perform RADON transformation on each pixel point in the two-dimensional target image to obtain the projection result of the two-dimensional target image vertically projected onto each projection line; and determine the projection results corresponding to the plurality of projection lines as the one-dimensional range image corresponding to the current observation angle.

[0118] In one embodiment of the present invention, the one-dimensional range image projection unit 704, when performing the RADON transformation on each pixel point in the two-dimensional target image, is further used to perform the RADON transformation on each pixel point in the two-dimensional target image using the following formula:

[0119]

[0120] Wherein, p is the vertical distance between the coordinate origin and the projection line of the two-dimensional target image, φ is the current observation angle, g(rcosθ,rsinθ) is the two-dimensional scattering function of the two-dimensional target image, r is the polar diameter of the pixel point in the polar coordinate system, θ is the angle of the pixel point in the polar coordinate system, δ() is the Dirac function, and R(p,φ) is the one-dimensional range image of the current observation angle.

[0121] In one embodiment of the present invention, the Fourier transform unit 705, when performing the fast Fourier transform on each one-dimensional range image, is specifically configured to perform the fast Fourier transform on each one-dimensional range image according to the following formula:

[0122]

[0123] Among them, G(ρ,φ) is the frequency data corresponding to the observation angle, R(p,φ) is the one-dimensional distance image, p is the vertical distance between the projection line and the coordinate origin, φ is the current observation angle, is the wave number, f is the frequency, c is the speed of light, and -j represents the conjugate complex number.

[0124] Please refer to Figure 8 , the image domain to RCS domain transformation device may also include:

[0125] The image preprocessing unit 706 is used to use the constructed regional gate function to perform at least one of corner attenuation processing, mouse drawing area processing and eraser processing on the two-dimensional target image, and use the processed two-dimensional target image to perform the projection of the two-dimensional target image.

[0126] Please refer to Fig. 9 , the image domain to RCS domain transformation device may also include:

[0127] The error correction unit 707 is used to determine the number of zero paddings performed on the one-dimensional range image and the type of window function used when performing fast Fourier transform; determine the error correction factor according to the number of zero paddings and the type of window function; and determine the product of the initial frequency data obtained after the fast Fourier transform and the error correction factor as the frequency data corresponding to the observation angle.

[0128] It is to be understood that the structure illustrated in the embodiment of the present invention does not constitute a specific limitation on a device for transforming from an image domain to an RCS domain. In other embodiments of the present invention, a device for transforming from an image domain to an RCS domain may include more or fewer components than shown in the figure, or combine some components, or split some components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0129] The information interaction, execution process and other contents between the modules in the above-mentioned device are based on the same concept as the embodiment of the method of the present invention. For specific contents, please refer to the description in the embodiment of the method of the present invention, and no further description is given here.

[0130] An embodiment of the present invention further provides a computing device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, a method for transforming from an image domain to an RCS domain in any embodiment of the present invention is implemented.

[0131] An embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the processor executes a method for transforming from an image domain to an RCS domain in any embodiment of the present invention.

[0132] Specifically, a system or device equipped with a storage medium can be provided, on which software program code that implements the functions of any of the above-mentioned embodiments is stored, and a computer (or CPU or MPU) of the system or device can be enabled to read and execute the program code stored in the storage medium.

[0133] In this case, the program code itself read from the storage medium can realize the function of any one of the above-mentioned embodiments, and thus the program code and the storage medium storing the program code constitute a part of the present invention.

[0134] The storage medium embodiments for providing the program code include a floppy disk, a hard disk, a magneto-optical disk, an optical disk (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), a magnetic tape, a non-volatile memory card, and a ROM. Alternatively, the program code can be downloaded from a server computer by a communication network.

[0135] In addition, it should be clear that the functions of any of the above embodiments can be implemented not only by executing the program code read by the computer, but also by enabling an operating system operating on the computer to complete part or all of the actual operations based on instructions from the program code.

[0136] In addition, it can be understood that the program code read from the storage medium is written to a memory provided in an expansion board inserted into the computer or to a memory provided in an expansion module connected to the computer, and then based on the instructions of the program code, a CPU installed on the expansion board or expansion module is enabled to perform part or all of the actual operations, thereby realizing the functions of any of the above-mentioned embodiments.

[0137] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical factors in the process, method, article or device including the elements.

[0138] A person of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk, etc., various media that can store program codes.

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for transforming from an image domain to an RCS domain, characterized in that: include: Determine the angle range corresponding to the transformation into the RCS domain; According to the angle range, acquiring a two-dimensional target image to be transformed; Determine each observation angle within the angle range according to a preset angle step; For each observation angle, the two-dimensional target image is projected according to a preset distance step by using RADON transformation to obtain a one-dimensional range image corresponding to each observation angle; Perform fast Fourier transform on each one-dimensional range image to obtain frequency data corresponding to each observation angle.

2. The method according to claim 1, characterized in that The step of acquiring the two-dimensional target image to be transformed according to the angle range includes: Using a radar to measure the RCS of a target, the angular domain range of the RCS measurement covers the angular range; Acquire corresponding data within the angle range from the RCS measured data; The acquired corresponding data within the angle range is converted into the two-dimensional target image.

3. The method according to claim 1, characterized in that The projecting the two-dimensional target images respectively according to the preset distance step by using the RADON transform includes: According to a current observation angle in each observation angle, determining a plurality of projection lines perpendicular to the current observation angle according to the preset distance step; Based on the vertical distance between the coordinate origin of the two-dimensional target image and each projection line, performing RADON transformation on each pixel point in the two-dimensional target image to obtain a projection result of the two-dimensional target image vertically projected onto each projection line; The projection results corresponding to the multiple projection lines are determined as a one-dimensional range image corresponding to the current observation angle.

4. The method according to claim 3, characterized in that The performing RADON transformation on each pixel point in the two-dimensional target image includes: The following formula is used to perform RADON transformation on each pixel in the two-dimensional target image: Wherein, p is the vertical distance between the coordinate origin and the projection line of the two-dimensional target image, φ is the current observation angle, g(rcosθ,rsinθ) is the two-dimensional scattering function of the two-dimensional target image, r is the polar diameter of the pixel point in the polar coordinate system, θ is the angle of the pixel point in the polar coordinate system, δ() is the Dirac function, and R(p,φ) is the one-dimensional range image of the current observation angle.

5. The method according to claim 3, characterized in that: The fast Fourier transform of each one-dimensional range image comprises: Perform a fast Fourier transform on each one-dimensional range image according to the following formula: Among them, G(ρ,φ) is the frequency data corresponding to the observation angle, R(p,φ) is the one-dimensional distance image, p is the vertical distance between the projection line and the coordinate origin, φ is the current observation angle, is the wave number, f is the frequency, c is the speed of light, and -j represents the conjugate complex number.

6. The method according to any one of claims 1 to 5, characterized in that: Before projecting the two-dimensional target images respectively, the method further includes: The constructed regional gate function is used to perform at least one of corner attenuation processing, mouse drawing area processing and eraser processing on the two-dimensional target image, and the processed two-dimensional target image is used to perform the projection of the two-dimensional target image.

7. The method according to any one of claims 1 to 5, characterized in that: After performing fast Fourier transform on each one-dimensional range image and before obtaining frequency data corresponding to each observation angle, the method further includes: Determine the amount of zero padding to be performed on the one-dimensional range image and the type of window function to be used when performing a fast Fourier transform; Determining an error correction factor according to the zero padding amount and the window function type; The product of the initial frequency data obtained after the fast Fourier transform and the error correction factor is determined as the frequency data corresponding to the observation angle.

8. A device for transforming from image domain to RCS domain, characterized in that: include: An angle range determination unit, used to determine the angle range corresponding to the transformation into the RCS domain; A two-dimensional target image acquisition unit, used for acquiring a two-dimensional target image to be transformed according to the angle range; An observation angle determination unit, used to determine each observation angle within the angle range according to a preset angle step; A one-dimensional range image projection unit is used to project the two-dimensional target image according to a preset distance step size using RADON transformation for each observation angle, so as to obtain a one-dimensional range image corresponding to each observation angle; The Fourier transform unit is used to perform fast Fourier transform on each one-dimensional range image to obtain frequency data corresponding to each observation angle.

9. A computing device, comprising a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to execute the method according to any one of claims 1 to 7.

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