Combustion surface retreating monitoring method based on cylindrical array three-dimensional imaging

Abstract

The invention relates to a combustion surface retreating monitoring method based on cylindrical array three-dimensional imaging. The combustion surface retreating monitoring method comprises the steps of obtaining a complete radar three-dimensional image; based on the two radar images, obtaining a registered image; phase information of the overlaying monitoring points is separated through differential interference processing; performing phase filtering according to the characteristics of noise in the interferogram; through phase unwrapping, a noise dense area is avoided, and unwrapping error propagation is reduced; and calculating the retreating amount. According to the embodiment of the invention, the problem that a plurality of scatterers in the same pixel unit cannot be distinguished in the elevation direction by a conventional differential interference technology is solved, and high-precision combustion surface back-moving information extraction is realized.

Description

Technical Field

[0001] The present disclosure relates to the technical field of radar imaging, and particularly to a method for monitoring the burning surface recession based on cylindrical array three-dimensional imaging. Background Art

[0002] In the prior art, a conventional two-dimensional radar imaging system does not have the height resolution ability, and cannot distinguish multiple scatterers within the same pixel unit. Overlay phenomena are likely to occur at the monitoring points in the image, resulting in problems of "unmeasurable" and "inaccurate measurement" in the recession inversion, and the recession information at the monitoring points of the solid rocket motor cannot be accurately obtained. Summary of the Invention

[0003] The present disclosure aims to provide a method for monitoring the burning surface recession based on cylindrical array three-dimensional imaging, which solves the problem that multiple scatterers within the same pixel unit cannot be distinguished in the elevation direction by the conventional differential interference technology, and realizes the extraction of high-precision burning surface recession information.

[0004] According to one of the solutions of the present disclosure, the method for monitoring the burning surface recession based on cylindrical array three-dimensional imaging includes:

[0005] Obtaining a complete radar three-dimensional image;

[0006] Based on two radar images, obtaining a registered image;

[0007] Through differential interference processing, separating the phase information of the overlay monitoring points;

[0008] Performing phase filtering according to the characteristics of the noise in the interferogram;

[0009] Through phase unwrapping to avoid noise-dense areas and reduce the propagation of unwrapping errors;

[0010] Calculating the recession amount.

[0011] In some embodiments, obtaining a complete radar three-dimensional image includes:

[0012] Obtaining the target echo signal;

[0013] Constructing a reference function;

[0014] Performing image focusing processing.

[0015] In some embodiments, obtaining the target echo signal includes:

[0016] Obtaining the echo signal of the target received by a single antenna element;

[0017] Determining the distance between the antenna element and the target;

[0018] Obtaining the echo signal of the entire target;

[0019] Obtain the target echo signal based at least on a three-dimensional inverse transform.

[0020] In some embodiments, constructing a reference function includes:

[0021] Uniformly divide the imaging area between the arc aperture radius and the set observable maximum distance into a plurality of cylindrical surfaces with different radii, and calculate the distance term of the approximate surface reference function;

[0022] Combine the target echo signal to obtain the reference function based on the approximate surface reference function.

[0023] In some embodiments, image focusing processing includes:

[0024] For discrete signals, achieve target reconstruction in the form of discrete value accumulation;

[0025] Repeat the operation for the cylindrical surfaces at all radii within the imaging area, arrange and integrate the imaging results of the profiles at different radii to obtain the complete radar three-dimensional image of the target.

[0026] In some embodiments, obtaining the registered image based on two radar images includes:

[0027] Perform three-dimensional imaging on the target before and after migration respectively to obtain two radar images;

[0028] Find the geometric transformation model between the main image and the auxiliary image through the corresponding relationship between homologous points;

[0029] Obtain the registered image according to the geometric transformation relationship between the main image and the auxiliary image.

[0030] In some embodiments, separating the phase information of the layover monitoring points through differential interferometry processing includes:

[0031] Independently extract the phase differences of each elevation layer, and separate the phase information of the layover monitoring points through elevation-direction layering processing.

[0032] In some embodiments, performing phase filtering for the characteristics of the noise in the interferogram includes:

[0033] Select the Goldstein filtering method, and perform phase filtering through frequency-domain adaptive weighting to balance noise suppression and phase detail retention.

[0034] In some embodiments, phase unwrapping includes:

[0035] After the two images are registered, obtain the interferogram by conjugate multiplication of the corresponding pixel points;

[0036] Phase unwrapping is performed by the branch cut method.

[0037] In some embodiments, sampling the echo data of the range cells to obtain spatio-temporal snapshots includes:

[0038] The radar extracts the minute target back-off amount by analyzing the differential phase between two images.

[0039] The method for monitoring the burning surface recession based on cylindrical array three-dimensional imaging according to various embodiments of the present disclosure can at least obtain a complete radar three-dimensional image; obtain a registered image based on two radar images; separate the phase information of the layover monitoring points through differential interferometric processing; perform phase filtering for the characteristics of the noise in the interferogram; perform phase unwrapping to avoid noise-dense areas and reduce the propagation of unwrapping errors; calculate the back-off amount, so as to maintain the azimuth-range resolution ability in traditional two-dimensional radar imaging while also having the elevation resolution ability. On this basis, a reference function is constructed, imaging is performed layer by layer along the range direction, and integration is performed along the k direction on each imaging layer, completely avoiding the interpolation operation of conventional three-dimensional imaging algorithms, reducing the computational amount in the imaging process without introducing any approximation, and being easier to implement; obtaining the recession information of the monitored burning surface on the target through differential interferometry based on the obtained radar three-dimensional image, solving the problem that conventional differential interferometry cannot distinguish multiple scatterers within the same pixel unit in the elevation direction, and realizing the extraction of high-precision burning surface recession information.

[0040] It should be understood that the foregoing general description and subsequent detailed description are exemplary and explanatory only and are not limiting of the claimed present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In the drawings, which are not necessarily drawn to scale, like reference numerals in different views may represent like components. Like reference numerals with alphabetic suffixes or like reference numerals with different alphabetic suffixes may represent different instances of like components. The drawings generally illustrate various embodiments by way of example and not limitation and are used in conjunction with the description and the claims to explain the disclosed embodiments.

[0042] Figure 1 Shows a flowchart of a method for monitoring the burning surface recession based on cylindrical array three-dimensional imaging according to an embodiment of the present disclosure;

[0043] Figure 2 Shows a schematic diagram of a radar cylindrical array antenna structure according to an embodiment of the present disclosure;

[0044] Figure 3 Shows a geometric diagram of a monitoring point according to an embodiment of the present disclosure;

[0045] Figure 4Shows a three-dimensional radar image of an embodiment of the present disclosure;

[0046] Figure 5 Shows the back-projection inversion result of an embodiment of the present disclosure. Detailed implementation manners

[0047] In order to make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. Apparently, the described embodiments are some but not all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts shall fall within the scope of protection of the present disclosure.

[0048] The burning surface recession rate is a key parameter characterizing the dynamic characteristics of the solid fuel combustion process, which directly affects the thrust and combustion stability of the engine. The traditional burning surface recession monitoring methods are mainly divided into two categories: contact type and non-contact type. The contact type method embeds thermocouples, fiber optic sensors and other devices on the inner wall of the combustion chamber or the fuel surface, and indirectly calculates the burning surface position using temperature or strain signals. However, the sensors need to be pre-installed outside the fuel, which poses a potential risk to the structural integrity of the engine. The non-contact type method obtains the burning surface information through external detection means, mainly including optical imaging, ultrasonic detection, etc. For the optical imaging monitoring method, the combustion products during the combustion of the grain will seriously block the line of sight and affect the monitoring results. The ultrasonic detection also has the problem of short continuous test time and cannot meet the real-time test of the propellant burning surface recession during the whole process of the solid engine combustion.

[0049] Radar is an active microwave remote sensor that can record the scattering intensity and phase information of the observed target and obtain a complex scattering image. However, the conventional two-dimensional radar image does not have the height resolution ability and cannot distinguish multiple scatterers within the same pixel unit.

[0050] Combined with the content recorded in the background art part above, the present disclosure exemplarily records corresponding solutions in the form of embodiments to solve the defects existing in the prior art, but does not limit the scope of patent protection required by the present disclosure.

[0051] As one of the solutions, the embodiment of the present disclosure provides a burning surface recession monitoring method based on cylindrical array three-dimensional imaging, including:

[0052] Obtain a complete radar three-dimensional image;

[0053] Based on two radar images, obtain a registered image;

[0054] Through differential interferometry, separate the phase information of the layover monitoring points;

[0055] Perform phase filtering according to the characteristics of noise in the interference pattern;

[0056] Through phase unwrapping, avoid noise-dense areas and reduce the propagation of unwrapping errors;

[0057] Calculate the back-off amount.

[0058] Regarding the foregoing content, each embodiment of the present disclosure aims to propose a method for monitoring the burning surface back-off based on cylindrical array three-dimensional imaging, which solves the problem that conventional differential interference technology cannot distinguish multiple scatterers within the same pixel unit in the elevation direction and realizes high-precision extraction of burning surface back-off information. First, the method of the present disclosure scans the target through a cylindrical array to obtain original echo data; secondly, uses the wavenumber domain imaging algorithm to process the echo signal to obtain a radar three-dimensional image of the target; performs differential interference processing on the radar three-dimensional images in adjacent time periods, where the differential interference processing includes complex image registration, interference pattern generation, phase filtering, phase unwrapping, and back-off amount calculation, and finally obtains the back-off information of the monitoring points of the engine grain.

[0059] The steps of the embodiments of the present disclosure, by way of example, in combination with Figure 1 The flowchart of the method for monitoring the burning surface back-off based on cylindrical array three-dimensional imaging shown in the embodiments of the present disclosure, the method for monitoring the burning surface back-off based on cylindrical array three-dimensional imaging of the present disclosure will be further described below by taking steps S1 to S6 as examples.

[0060] In some specific implementation manners, the present disclosure may be to obtain a complete radar three-dimensional image, including: obtaining the target echo signal; constructing a reference function; and image focusing processing.

[0061] Step S1: Perform three-dimensional imaging on the target.

[0062] In some specific implementation manners, the present disclosure may be to obtain the target echo signal, including: obtaining the echo signal of the target received by a single antenna element; determining the distance between the antenna element and the target; obtaining the echo signal of the entire target; and obtaining the target echo signal based on at least three-dimensional inverse transformation.

[0063] Step S11: Obtain the target echo signal.

[0064] Conventional two-dimensional imaging radars synthesize a one-dimensional aperture in the azimuth direction to obtain the echo signal in the target, and can only obtain the resolution in the azimuth and range directions, lacking the elevation resolution ability.

[0065] Each embodiment of the present disclosure uses a cylindrical array antenna to construct a two-dimensional aperture to obtain three-dimensional space echo data. Figure 2The figure shows a schematic diagram of a radar cylindrical array antenna. The target to be measured is located within the rectangular coordinate system OXYZ, and a set of antenna arrays is set up in the vertical direction. A continuous wave signal with a bandwidth of B is radiated and received. The antenna array rotates around the Z-axis in a circular motion with a radius of ρ′ within an angular range of [-30°, 30°], thereby constructing a cylindrical antenna array. The coordinates of the antenna element in the Cartesian coordinate system are T(x′, y′, z′), and the corresponding cylindrical coordinates are T(ρ′, θ′, z′); the coordinates of the target in the Cartesian coordinate system are P(x, y, z), and the corresponding cylindrical coordinates are P(ρ, θ, z).

[0066] The antenna array performs penetrative imaging on the grain. Assuming that the grain medium exhibits uniform characteristics, and has no loss characteristics and dispersion characteristics, to simplify the observation model. At this time, under the assumption of a uniform medium, the electromagnetic wave propagation speed C m can be expressed as

[0067]

[0068] where ε r is the relative permittivity, and u r is the relative permeability. The grain of a solid rocket motor is mainly composed of solid propellant, which usually consists of oxidizer, metal fuel, binder, and additives. In the case of low metal content, let its permittivity be 4, and the relative permeability u r is usually taken as 1.

[0069] The echo signal of the target received by a single antenna element at the position T(ρ′, θ′, z′) can be expressed as:

[0070] s(k, θ′, z′) = I(ρ, θ, z)exp(-j2kR) (2)

[0071] where I(ρ, θ, z) is the scattering coefficient of the target, k ∈ [k min , k max , k min = 2πf min / C m and k max = 2πf max / C m are the wave numbers of the minimum frequency f min and the maximum frequency f max respectively, C m is the propagation speed of the electromagnetic wave in the medium, and R is the distance between the antenna element and the target, which can be expressed as:

[0072]

[0073] In this case, the echo signal of the entire target observed can be expressed as:

[0074] S(k, θ′, z′) = ∫∫∫I(ρ, θ, z) exp(-j2kR) dν (4)

[0075] For the cylindrical array three-dimensional imaging used in the embodiments of the present disclosure, |θ - θ′| ≤ θ y / 2, where θ y represents the beam width of the antenna array in the azimuth direction; |z - z′| ≤ L z / 2, where L z represents the length of the antenna array in the height direction. Integrating the echo signal by performing a three-dimensional inverse transform with respect to k, θ′, and z′, the following can be obtained:

[0076]

[0077] Express exp(+j2kR) in Equation (5) as the following integral form:

[0078]

[0079] Substitute Equation (6) into Equation (5) and exchange the order of integration, then the following can be obtained:

[0080]

[0081] Where:

[0082] S(k, θ′, k z ) = ∫ z′ S(k, θ′, z′) exp(-jk z z′) dz′ (8)

[0083]

[0084] In some specific implementation manners, the present disclosure may be to construct a reference function, including:

[0085] Uniformly divide the imaging area between the arc aperture radius and the set maximum observable distance into a plurality of cylindrical surfaces with different radii, and calculate the distance term of the approximate surface reference function;

[0086] Combine the target echo signal to obtain a reference function based on the approximate surface reference function.

[0087] Step S12: Construct a reference function.

[0088] Uniformly divide the imaging area between the arc aperture radius and the set maximum observable distance into N cylindrical surfaces with different radii, and calculate the distance term of the approximate surface reference function. The calculation formula is as follows:

[0089]

[0090] Among them, represents the exact value of the approximate surface reference function distance term. Substituting Equation (10) into Equation (9), the reference function of the approximate surface can be obtained as:

[0091]

[0092] Substituting Equation (11) into Equation (7) and converting the integral with respect to the azimuth angle θ′ into a convolution operation, we can obtain:

[0093]

[0094] Among them, * represents the convolution operation in the angular domain. To further improve the operation efficiency, the fast Fourier transform can be used to reduce the computational complexity. Therefore, in Equation (12) can be expressed in the following form:

[0095]

[0096] Among them:

[0097]

[0098] FFT θ represents the fast Fourier transform with respect to θ.

[0099] In some specific implementation manners, the present disclosure may be for image focusing processing, including:

[0100] For discrete signals, target reconstruction is achieved in the form of discrete value accumulation;

[0101] The operation is repeated for all cylinders at all radii within the imaging region, and the imaging results of the profiles at different radii are arranged and integrated to obtain the complete three-dimensional radar image of the target.

[0102] Step S13, image focusing processing.

[0103] For discrete signals, the one-dimensional integral with respect to k in Equation (12) can also be converted into a summation of discrete values, and then target reconstruction can be achieved in the following form of discrete value accumulation:

[0104]

[0105] Among them, represents along k θ and k zInverse fast Fourier transform in the direction. Equation (15) indicates that when the sampling criterion is met, for profile imaging, the same operation is repeated for the cylinders at all radii within the imaging region, and the imaging results of the profiles at different radii are arranged and integrated to obtain the three-dimensional reconstruction image of the target. The complete three-dimensional radar image obtained can be expressed as:

[0106]

[0107] In some specific embodiments, the present disclosure can be to obtain a registered image based on two radar images, including:

[0108] Perform three-dimensional imaging on the target before and after migration respectively to obtain two radar images;

[0109] Find the geometric transformation model between the main image and the auxiliary image through the corresponding relationship between homologous points;

[0110] Obtain the registered image according to the geometric transformation relationship between the main image and the auxiliary image.

[0111] Step S2: Radar complex image registration.

[0112] Perform three-dimensional imaging on the target before and after migration respectively to obtain two radar images. Registration is a prerequisite for solving the interference phase of two radar images. By finding the corresponding relationship between homologous points, the geometric transformation model between the main image and the auxiliary image is found, and the registered image is obtained according to their geometric transformation relationship. The phase gradient method is used to register the complex image. The phase gradient method is sensitive to small migrations and is suitable for high-resolution three-dimensional imaging.

[0113] In some specific embodiments, the present disclosure can be to separate the phase information of the layover monitoring points through differential interferometry, including: independently extracting the phase differences of each elevation layer, and separating the phase information of the layover monitoring points through elevation-layered processing.

[0114] Step S3: Differential interferometry processing.

[0115] The conventional differential interferometry process is to obtain the migration information at the monitoring points by analyzing the mapping relationship between the phase change and the displacement amount at the monitoring points within adjacent imaging periods. However, when calculating the phase difference in the two-dimensional interferogram, the migration signals of different elevation monitoring points within the same pixel cannot be separated, which will lead to confusion in the inversion results. The present invention performs differential interferometry processing based on three-dimensional radar images, independently extracts the phase differences of each elevation layer, and separates the phase information of the layover monitoring points through elevation-layered processing.

[0116] The radar uses differential interferometry measurement technology to invert the migration of the monitoring points by analyzing the phase difference. The reference plane at a distance ρ from the radar can be expressed as:

[0117]

[0118] Among them, PSF represents the time-domain point spread function. Assume that the target migration amount is Δρ. For the resolution cell of the radar image, when the target migrates, the slant range within the resolution cell will change. The radar image after migration can be expressed as follows:

[0119]

[0120] Among them, Δρ is the migration amount of the target line of sight relative to the radar. By multiplying the radar images before and after migration conjugately, the result is given by the following formula:

[0121]

[0122] Among them, * represents complex conjugation, and the phase information in formula (19) contains the target migration information. When the phase in formula (19) is within the range [-π, π], the relationship between the differential phase and the target migration can be directly obtained:

[0123]

[0124] In some specific implementation manners, the present disclosure may be to perform phase filtering according to the characteristics of the noise in the interferogram, including: selecting the Goldstein filtering method, and performing phase filtering through frequency-domain adaptive weighting to balance noise suppression and phase detail retention.

[0125] Step S4: Phase filtering.

[0126] The noise in the interferogram includes system noise, noise caused by image registration error, noise caused by image decorrelation, etc. According to the characteristics of the noise in the interferogram, the Goldstein filtering method is selected for phase filtering. This method can effectively balance noise suppression and phase detail retention through frequency-domain adaptive weighting.

[0127] In some specific implementation manners, the present disclosure may be phase unwrapping, including: after registering two images, obtaining an interferogram by conjugately multiplying corresponding pixel points; performing phase unwrapping by the branch cut method.

[0128] Step S5: Phase unwrapping.

[0129] When two images are registered, an interferogram between them can be obtained by conjugately multiplying the corresponding pixel points in the two images. Thereafter, phase unwrapping is the key to solving the true phase. It is related to whether the finally obtained target migration amount is accurate. The branch cut method is used for phase unwrapping. This method can effectively avoid noise-dense regions, reduce the propagation of unwrapping errors, and has a low algorithm complexity, which is suitable for large-scale data processing and meets the real-time requirements.

[0130] In some specific embodiments, the present disclosure may be to sample the echo data of the range unit to obtain spatio-temporal snapshots, including: the radar extracts the target's micro-displacement amount by analyzing the differential phase between two images.

[0131] Step S6: Calculate the displacement amount

[0132]

[0133] At this time, the radar extracts the target's micro-displacement amount by analyzing the differential phase between two images.

[0134] The feasibility of the burning surface displacement monitoring method based on cylindrical array three-dimensional imaging is verified through the above steps. In the burning surface displacement monitoring scenario, the combustion situation of the solid rocket motor grain is monitored, and three monitoring points A, B, and C are introduced. The observation geometry of the monitoring points is as shown in Figure 3 the monitoring point geometry diagram shown. The coordinates of the radar aperture center and each monitoring point are shown in Table 1, and it is set that the monitoring points A, B, and C are displaced according to Table 2.

[0135] Table 1 Radar and monitoring point coordinates

[0136] Radar Aperture center / m Monitoring point Three-dimensional coordinates / m R (0,0,0) A (5,0,0) B (4,0,-3) C (3,0,-4)

[0137] Table 2 Displacement information of each monitoring point

[0138] Monitoring point Retreat direction Retreat amount / mm A X-axis 2.0 B 0 C X-axis 1.0

[0139] After performing the above steps, the three-dimensional images before and after the radar displacement are as shown in Figure 4 the radar three-dimensional image shown. Among them, Figure 4 part (a) shows the original image, and part (b) shows the image after displacement.

[0140] Through differential interferometry of the two radar three-dimensional images, the displacement amounts of each monitoring point obtained are as shown in Figure 5 the displacement inversion result shown. Among them, Figure 5 part (a) shows the inversion result of point A, part (b) shows the inversion result of point B, and part (c) shows the inversion result of point C.

[0141] It should be noted that since the focus of the present disclosure is on the high-precision inversion of the displacement amount of the layover target, the simulation experiments are all carried out under ideal conditions. The complex image registration and phase filtering operations in the above differential interferometry process can be ignored; the set displacement amounts are all within the range of λ / 4, so the phase unwrapping operation is not required either. The error analysis is shown in Table 3.

[0142] Table 3 Error analysis of differential interferometry results

[0143] Monitoring point Theoretical retreat amount / mm Inversion result / mm Error / mm A 2.0 2.0083 0.0083 B 0 -0.0015 -0.0015 C 1.0 0.9995 -0.0005

[0144] The results show that the burning surface recession monitoring method based on cylindrical array three-dimensional imaging can accurately extract the recession amount of the "layover" monitoring points, and can support the high-resolution inversion of the recession amount during the burning surface recession process.

[0145] Compared with the prior art, the beneficial effects of the burning surface recession monitoring method based on cylindrical array three-dimensional imaging in various embodiments of the present disclosure are at least reflected in: imaging the target through a cylindrical aperture radar, and performing differential interferometry based on the obtained radar three-dimensional image, the steps of which include complex image registration, interferogram generation, phase filtering, phase unwrapping, and recession amount calculation, solving the pain points of conventional DInSAR in the burning surface monitoring of solid rocket motors, that is, the accurate extraction of monitoring points cannot be achieved for the problem of scatterer layover. The results show that the burning surface recession monitoring method proposed by the present invention can respectively obtain high-precision recession information at the layover monitoring points on the solid rocket motor, providing a theoretical basis for solving the problem of scatterer layover that may occur in the burning surface recession monitoring.

[0146] Based on the above inventive concept, the burning surface recession monitoring method based on cylindrical array three-dimensional imaging in various embodiments of the present disclosure at least obtains a complete radar three-dimensional image; based on two radar images, obtains a registered image; through differential interferometry processing, separates the phase information of the layover monitoring points; performs phase filtering according to the characteristics of the noise in the interferogram; through phase unwrapping, to avoid noise-intensive areas and reduce the propagation of unwrapping errors; calculates the recession amount, so as to have the resolution ability in the elevation direction while maintaining the azimuth-range resolution ability in traditional two-dimensional radar imaging. On this basis, a reference function is constructed, imaging layer by layer along the range direction, and integrating along the k direction on each imaging layer, completely avoiding the interpolation operation of conventional three-dimensional imaging algorithms, reducing the calculation amount in the imaging process and not introducing any approximation, and being easier to implement; obtaining the recession information of the burning surface of the monitoring point on the target through differential interferometry technology based on the obtained radar three-dimensional image, solving the problem that conventional differential interferometry technology cannot distinguish multiple scatterers within the same pixel unit in the elevation direction, and realizing the extraction of high-precision burning surface recession information.

[0147] The present disclosure also provides a burning surface recession monitoring device based on cylindrical array three-dimensional imaging, including one or more processing modules, configured to perform the burning surface recession monitoring based on cylindrical array three-dimensional imaging described above, and at least configured to be able to execute the specific implementation manners of steps S1 to S6.

[0148] The present disclosure also provides a computer-readable storage medium, on which computer-executable instructions are stored. When the computer-executable instructions are executed by a processor, it mainly implements the burning surface recession monitoring method based on cylindrical array three-dimensional imaging according to the above, at least including:

[0149] Obtain a complete three-dimensional radar image;

[0150] Based on two radar images, obtain the registered image;

[0151] Through differential interferometry processing, separate the phase information of the layover monitoring points;

[0152] Perform phase filtering according to the characteristics of the noise in the interferogram;

[0153] Through phase unwrapping, avoid noise-dense areas and reduce the propagation of unwrapping errors;

[0154] Calculate the migration amount.

[0155] The above embodiments are only exemplary embodiments of the present disclosure and are not used to limit the present disclosure. The protection scope of the present disclosure is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present disclosure, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the present disclosure.

Claims

1. A combustion surface retreat monitoring method based on cylindrical array three-dimensional imaging, comprising: Get a complete radar 3D image; Based on the two radar images, a registered image is obtained; Separate the phase information of overlapping monitoring points through differential interferometry processing; Perform phase filtering based on the characteristics of noise in the interference pattern; Through phase unwrapping, we can avoid noise-intensive areas and reduce the propagation of unwrapping errors; Calculate the amount of setback.

2. The method according to claim 1, wherein: Get a complete radar 3D image, including: Acquire target echo signal; Construct reference function; Image focus processing.

3. The method according to claim 2, wherein: Obtain target echo signals, including: Obtain the echo signal of the target received by a single antenna array element; Determine the distance between the antenna array element and the target; Get the echo signal of the entire target; A target echo signal is obtained based at least on the three-dimensional inverse transform.

4. The method according to claim 3, wherein: Construct reference functions, including: The imaging area between the arc aperture radius and the set maximum observable distance is evenly divided into multiple cylinders with different radii, and the distance term of the approximate surface reference function is calculated; Combined with the target echo signal, a reference function is obtained based on the approximate surface reference function.

5. The method according to claim 4, wherein: Image focus processing, including: For discrete signals, target reconstruction is achieved by accumulating discrete values; The operation is repeated for cylinders at all radii within the imaging area, and the imaging results of profiles at different radii are arranged and integrated to obtain a complete radar three-dimensional image of the target.

6. The method according to claim 5, wherein: Based on the two radar images, the registered image is obtained, including: The target before and after the retreat is imaged in three dimensions to obtain two radar images; Through the correspondence between the same-name points, the geometric transformation model between the main image and the auxiliary image is found; According to the geometric transformation relationship between the main image and the auxiliary image, the registered image is obtained.

7. The method according to claim 6, wherein: Through differential interferometry processing, the phase information of overlapping monitoring points is separated, including: The phase difference of each elevation layer is extracted independently, and the phase information of overlapping monitoring points is separated through elevation stratification processing.

8. The method according to claim 7, wherein: Phase filtering is performed based on the characteristics of the noise in the interference pattern, including: The Goldstein filtering method is selected, and phase filtering is performed through frequency domain adaptive weighting to balance noise suppression and phase detail retention.

9. The method according to claim 8, wherein: Phase unwrapping, including: After the two images are registered, the interference pattern is obtained by conjugate multiplication of corresponding pixels; Phase unwrapping by branch cutting.

10. The method according to claim 9, wherein: The echo data of the range unit is sampled to obtain space-time snapshot data, including: The radar extracts the tiny displacement of the target by analyzing the differential phase between the two images.

Images