166 results about "Phase map" patented technology

The invention relates to the technical field of remote sensing science and technology, in particular to a frozen soil region freeze-thaw disaster identification method and system and a storage medium, and the method comprises the steps: generating a target differential interference image set; carrying out homogeneous point filtering, phase unwrapping optimization and unwrapping error correction on the basis of the target differential interference image set to obtain an unwrapped phase image set; for each unwrapped phase diagram, performing uniform sub-block division, and based on an elevation-phase empirical relationship, estimating and removing an atmospheric delay phase existing in each sub-block through a linear fitting method to obtain a phase optimization diagram set after atmospheric influence is removed; performing sequential superposition on unwrapping phases corresponding to the interferograms in the phase optimization diagram set, and performing analysis by using the relationship between the average phase change rate after superposition and the radar wavelength to obtain earth surface deformation data; and unsupervised classification and screening are carried out based on the earth surface deformation data, and freeze-thaw change areas are optimized, so that a high-precision freeze-thaw recognition result is obtained.

The invention discloses a distributed denial of service attack defense method and system, a medium and a program product, and the method comprises the steps: calculating feature parameters of network flow data; generating a multi-dimensional feature vector; constructing a time sequence state transition matrix; extracting a feature root sequence, and calculating a modulus length change rate; constructing a dynamic phase diagram based on the mode length change rate; the Euclidean distance between adjacent orbit points in the dynamic phase diagram is calculated, when it is determined that an abnormal attractor appears, corresponding flow data are extracted, and a self-similarity index is calculated; when the self-similarity index is greater than a third preset threshold value, determining a high danger level; when the value is greater than a fourth preset threshold and less than or equal to a third preset threshold, determining that the danger level is a middle danger level; when less than or equal to a fourth preset threshold, determining that the danger level is low; executing a discarding strategy on the high danger level; executing a bandwidth limiting strategy for the middle danger level; a delayed forwarding policy is performed for a low hazard level. The accuracy of formulating and implementing the protection strategy is improved, and the security of the network is further improved.

The invention discloses a phase unwrapping method and device based on Poisson correction, terminal equipment and a storage medium, and relates to the field of interferometry, and the method comprises the steps: obtaining a to-be-processed interferometric phase diagram of a target position, and inputting the to-be-processed interferometric phase diagram into a winding number prediction model to generate a predicted winding number; according to the predicted winding number, calculating a winding number gradient, and performing lower edge filtering correction to obtain a corrected winding number gradient; performing discrete Fourier transform on the corrected horizontal component of the winding number gradient to obtain a first frequency domain transform result; carrying out Laplace operator calculation on the corrected winding number gradient and then carrying out discrete Fourier transform to obtain a second frequency domain transform result; performing inverse discrete Fourier transform on a result obtained by dividing the sum of the two frequency domain transform results by a preset frequency domain adjustment factor to obtain an error winding number; and determining a real phase according to the predicted winding number and the error winding number, and further calculating the actual elevation of the target position. According to the invention, the accuracy of phase unwrapping can be improved.

The invention discloses an SAR (Synthetic Aperture Radar) image overlay detection method, device and equipment and a storage medium. The method comprises the following steps: acquiring SAR time sequence image data, external DEM (Digital Elevation Model) data and external earth surface classification coverage data of a current detection area; obtaining a region amplitude diagram of the current detection region according to the SAR time sequence image data, and carrying out normalization processing on the region amplitude diagram; obtaining a corresponding interferometric phase diagram according to the SAR time sequence image data, and calculating a coherence coefficient; performing normalization processing on the external DEM data, performing wave band splicing on the normalized region amplitude diagram, interference phase diagram and coherence coefficient, and the normalized external DEM data and external earth surface classification coverage data to generate a corresponding data block, and inputting the data block into a preset overlay identification model, and obtaining an overlay identification result of the current detection area. The SAR overlay recognition method can improve the overlay recognition precision of the SAR.

The invention relates to the technical field of optical precision interference measurement, in particular to a correction method for projection distortion detection of a primary mirror of a dynamic interferometer and a related product, and the method comprises the steps: obtaining a first coordinate and a second coordinate; determining a zero distortion point; obtaining an ideal imaging point set and an actual mapping point set after system projection through ray tracing; fitting to obtain a distortion function representing the distortion of the optical system; performing point-by-point correction on a phase diagram obtained by interference measurement, mapping pixel coordinates of the phase diagram into workpiece coordinates, obtaining interference measurement data corresponding to the actual surface of the primary mirror, and completing distortion correction; according to the method for correcting the surface shape projection distortion during interference measurement of the high-precision primary mirror of the large-aperture dynamic interferometer, the problem that in the process of assembling, repairing and developing the large-aperture Twyman type dynamic interferometer, the projection distortion effect of a detection system causes the loss of an accurate matching relation between a workpiece coordinate system and a detection coordinate system is solved.

The invention provides a real-time holographic phase unwrapping and phase distortion elimination method and system, computer equipment and a storage medium. The method comprises the following steps: acquiring and recording a hologram of an object to be measured; preprocessing the hologram to obtain a wrapped phase diagram; inputting the parcel phase diagram into an HS-TransUNet neural network to carry out parcel counting segmentation so as to obtain a parcel number diagram; multiplying the wrapping number diagram by 2pi and then superposing the wrapping number diagram and the wrapping phase diagram to obtain an unwrapping phase diagram; inputting the unwrapped phase diagram into an HS-TransUNet neural network to carry out background segmentation so as to obtain a background image; inputting the background image into an HS-ResNet50 neural network to obtain the first six Zernike coefficients; performing prediction by using the first six Zernike coefficients to obtain background distortion data; and subtracting the background distortion data from the unwrapped phase diagram to obtain a real phase of the target object. The method can realize real-time high-precision holographic phase unwrapping and phase distortion elimination.

The invention relates to a synthetic aperture radar interferometry phase unwrapping method based on a convolutional neural network and a visual converter, and belongs to the technical field of synthetic aperture radar interferometry. Aiming at the problem that a traditional deep learning method is insufficient in phase unwrapping precision in a complex terrain and noise environment, the method comprises the following steps of inputting a synthetic aperture radar interferogram to be unwrapped, extracting local features by using a convolutional neural network, generating a fusion feature map through a multi-scale feature capture module, and performing phase unwrapping on the fusion feature map; and after channel weights are adjusted through an extrusion-excitation network, a single-head self-attention mechanism is applied to capture a global relationship, and finally a continuous phase diagram is reconstructed through a convolutional layer. According to the method, local feature extraction and global relation modeling are effectively combined, the processing capacity for a phase jump area and noise is improved, the method is suitable for phase unwrapping of large-gradient surface deformation areas such as mining areas, continuous phase information in interference measurement can be accurately recovered, and accurate data support is provided for application such as surface deformation monitoring.

The present invention discloses a holographic grating self-calibration method, which relates to the field of optical technology, including collecting interference image data and performing preprocessing, extracting phase data of the interference image data after preprocessing; generating a phase map based on the phase data to perform holographic grating self-calibration, and evaluating and adjusting the result of the holographic grating self-calibration; constructing a visual interface to display the holographic grating self-calibration in real time, implementing secure encryption on the phase data, and storing, collecting and analyzing the generated data. The present invention collects interference image data and performs preprocessing, extracts phase data of the interference image data after preprocessing, and generates a phase map based on the phase data to perform holographic grating self-calibration, which greatly simplifies the calibration process, improves the convenience of operation and the extraction accuracy of phase data, and significantly improves the calibration accuracy and stability of the holographic grating.

The invention discloses a light field display method and system with holography as a representation medium, and the method comprises the following steps: S1, collecting a multi-view image of a target scene, carrying out the coding of the multi-view image, and generating a light field tensor containing space and angle information; s2, mapping the light field tensor in the step S1 into a two-dimensional space phase diagram; s3, converting the two-dimensional space phase diagram in the step S2 into a modulation diagram used for driving a spatial light modulator; and S4, driving the spatial light modulator to perform light wavefront modulation according to the modulation graph in the step S3, and reproducing the image of the target scene through optical diffraction. According to the invention, integration from dynamic scene information acquisition to high-quality three-dimensional image reproduction is realized, a low-redundancy and high-fidelity processing link is realized, and the efficiency and quality of holographic display are greatly improved.

The invention discloses a ship identification method based on multiple acoustic feature fusion. The ship identification method comprises the following steps: acquiring and preprocessing underwater noise signals of a ship; carrying out MEL frequency spectrum, CQT frequency spectrum and STFT phase diagram feature transformation on the preprocessed ship underwater noise signals, and carrying out stacking on channel dimensions to obtain three-channel feature images; constructing a recognition neural network; performing feature extraction on the three-channel feature image through an asymmetric convolution feature extraction module to obtain a preliminary feature; strengthening the preliminary features through a feature strengthening module to obtain strengthened features; and performing classification identification on the reinforced features through a classification module to obtain an identification result. Through multiple acoustic feature extraction, deep information in original data is mined and utilized to the greatest extent while the calculation cost is reduced, the noise robustness is excellent, the model structure is simple, and the recognition effect can be effectively improved.

Disclosed is a structured light three-dimensional measurement method based on joint multi-frequency heterodyne and time-gated overlapping coding strategy. Specifically, fringe images modulated by a target surface are firstly collected and processed to obtain corresponding wrapped phase maps according to the phase-shifting method. Then, the wrapped phase maps are re-organized following the time-gated overlapping coding strategy, and further proceeded to obtain corresponding multi-frequency heterodyne unwrapped phase maps. With the unwrapped phase maps, a corresponding three-dimensional point cloud can be derived with the calibration parameters. The present application uses multi-frequency heterodyne method for phase unwrapping, promising high stability of phase-unwrapping and high measurement accuracy. Furthermore, the temporal correlation among the fringe images is fully exploited by the proposed time-gated overlapping coding strategy to further improve the measurement accuracy. Besides, only a few sinusoidal fringe images need to be used to complete one single measurement, highly promoting the measuring speed.

The invention discloses a field calibration method and system for SMT 3D AOI equipment, and relates to the surface mounting technology, and the method comprises the steps: feeding a calibration board into the SMT 3D AOI equipment according to the same board feeding mode as a common PCB, and carrying out the initialization; multiple groups of horizontal and vertical grating images are acquired; performing phase calculation on the grating image acquired by the camera by using a phase shift method to obtain a plurality of groups of horizontal and vertical phase diagrams; performing image processing on the calibration plate image acquired by the camera, calculating circle center coordinates of all the circular patterns, and calculating corresponding point coordinates of the circle center coordinates on the imaging plane of each projector; calculating coordinate values of all circle centers on the calibration plate in a world coordinate system according to the adopted Z-axis height and the distance between the circular patterns of the calibration plate; repeatedly calculating world coordinates; and determining optimized system parameters according to the projection process of conversion from the coordinate values of the world coordinate system to the camera pixel coordinate system. According to the invention, the internal parameters and the external parameters of the equipment can be quickly optimized, and the precision of the imaging system is recovered to the initial state.

The invention relates to a speckle interferometric phase diagram filtering method based on a conditional diffusion model, and belongs to the technical field of optical measurement. The method comprises the following steps: S1, obtaining training data: generating or collecting multiple groups of paired speckle interferometric phase diagrams including noisy speckle interferometric phase diagrams and corresponding denoising reference phase diagrams; s2, constructing a conditional diffusion model; S3, training the conditional diffusion model: training the diffusion model in a supervision mode; and S4, taking the to-be-processed phase diagram as a conditional image, and generating a denoised phase diagram through a back diffusion process. According to the invention, the noise processing accuracy of the phase diagram in laser speckle interference measurement can be improved.

The invention discloses a multi-focus laser micro-nano manufacturing method and system, and relates to the technical field of laser processing, and the method comprises the steps: analyzing SVG vector coding information of a processing pattern; an LCOS-SLM multi-focus array is obtained by adopting an annular segmentation algorithm; adjusting the size of the graph, carrying out discretization processing on the graph, and carrying out interval homogenization processing on coordinate points of the graph; dividing the uniformly dispersed graph into n processing areas, and grouping coordinate information by taking uniform distribution of focus positions as a principle to obtain a processing path; substituting the coordinate information of each partition into an annular segmentation algorithm to generate a holographic phase image set; and splicing parameters between the machining areas are calibrated, and multi-focus parallel machining is completed. The efficient laser parallel machining method is achieved, the efficiency and stability of a laser machining system and the machining uniformity of a curve structure can be improved, and an efficient and reliable solution is provided for the field of micro-nano machining.

The invention discloses a color Gray code coding auxiliary phase unwrapping method and an applied three-dimensional imaging method and system, and belongs to the technical field of three-dimensional imaging. The method comprises the following steps: constructing two groups of colored sine stripe patterns with different frequencies, projecting a scene to be detected, and capturing the two groups of stripe patterns; converting the stripe pattern from an RGB format into an HSV format, extracting a hue channel and performing Gray code decoding; extracting a hue channel from the RGB-format fringes to perform intensity normalization processing, then filling the hue channel into a single-channel image, calculating a wrapped phase by using a phase shift formula, then calculating heterodyne phases of fringe patterns with different frequencies through a multi-frequency heterodyne method, and performing first unwrapping on the wrapped phase; and unfolding the phase diagram which is unfolded for the first time in an auxiliary manner by utilizing a Gray code decoding order, thereby obtaining a final absolute phase. Gray codes are coded and embedded into different channels of two groups of patterns, so that the number of required patterns is remarkably reduced, and the measurement efficiency is effectively improved.

The invention discloses an image-based suspension bridge surface anomaly measurement method and measurement system, and relates to the technical field of optical measurement and image processing. The method comprises the following steps: projecting a first polarization grating and a second polarization grating with mutually orthogonal polarization directions to a to-be-measured area of the suspension bridge in a time-sharing manner; polarization information of reflected light is collected by adopting a polarization state imaging unit, and corresponding first and second Moire phase diagrams are generated. The data processing unit further performs double-path parallel processing on the two Moire phase diagrams: on one hand, a two-dimensional inclined field representing the macroscopic contour of an object is solved through a joint solution algorithm; and on the other hand, through differential operation, microscopic optical anisotropy abnormal points caused by material stress, damage and the like are identified and positioned by utilizing symmetrical response of the optical isotropic surface to the orthogonal grating. The method realizes synchronous decoupling of geometric and physical characteristics from a single data source through one-time measurement, has the advantages of non-contact and high efficiency, and is suitable for precise detection of large-scale structures such as a suspension bridge and the like.

Embodiments of the present application provide a deep learning-based phase unwrapping method and apparatus, a device, and a medium. The method comprises: acquiring a wrapped phase map; and inputting the wrapped phase map into a pre-trained deep learning network model and performing phase unwrapping, such that the deep learning network model outputs, on the basis of a non-linear mapping relationship between wrapped phases and absolute phases, an absolute phase map corresponding to the wrapped phase map, wherein the deep learning network model adopts a U-Net framework and comprises an encoder, a decoder, a deep-supervision feature fusion module, and an atrous spatial pooling pyramid module, and the encoder and the decoder comprise Inception modules. On this basis, even in high-noise environments and in the presence of phase discontinuity, the embodiments of the present application enable a trained deep learning network model to predict a high-quality absolute phase map in just one step, thereby achieving accurate phase unwrapping.

This invention discloses a three-dimensional contour measurement method and apparatus based on multi-projection gratings, relating to the field of three-dimensional topography measurement technology. The method includes: obtaining intrinsic and extrinsic parameters through calibration; projecting a set of speckle patterns; preliminarily analyzing the surface topography gradient of the object to determine a non-uniform spatial frequency sequence; sequentially projecting and acquiring multiple sets of phase-shifting grating patterns, and calculating the wrapping phase map corresponding to each frequency; for the same pixel, based on its reliability assessment in wrapping phase maps at different frequencies, assigning confidence weights to the phase values ​​of each frequency, and calculating and optimizing the phase map and the corresponding fused confidence map; calculating gradient information and combining it with the fused confidence map to perform region division, and executing a region-guided path consistency verification unfolding algorithm to obtain the absolute phase; converting the absolute phase into three-dimensional point cloud coordinates of the object surface. This application aims to solve the problems of complex topography, discontinuities, and noise easily leading to unfolding path errors and order jumps during phase unfolding.

For reconstruction in medical imaging using phase correction, a machine learning model is trained for reconstruction of an image. The reconstruction may be for a sequence without repetitions or may be for a sequence with repetitions. Where repetitions are used, rather than using just a loss for that repetition in training, the loss based on an aggregation of images reconstructed from multiple repetitions may used to train the machine learning model. In either approach, a phase correction is applied in machine training. A phase map is extracted from output of the model in training or extracted from the ground truth of the training data. The phase correction, based on the phase map, is applied to the ground truth and / or the output of the model in training. The resulting machine-learned model may better reconstruct an image as a result of having been trained using phase correction.

The present application relates to the field of information optics, more particularly, to a spatial structure vertical focal field generation method and system. The present application provides a spatial structure vertical focal field generation method, according to the constructed phase map of the spatial structure vertical focal field, the incident light beam is modulated into a cylindrical wave light beam at the light beam modulation, and then the cylindrical wave light beam is focused to generate a spatial structure vertical focal field. Wherein, the phase map only needs to be calculated according to the superposition of the column lens phase or the column lens phase and the flash grid phase, and the calculation amount and calculation time are obviously reduced compared with the iterative calculation of the existing method. The present application solves the problems of large calculation amount and long time consumption of the existing method for generating a spatial structure vertical focal field.

The invention discloses a Fourier lamination microscopy high-resolution reconstruction system based on a WSTFPM (Wavelet Transform Template Fabry-Perot Microscopy). A traditional FPM reconstruction method has the defects of low time resolution, poor robustness under system aberration and the like. The method comprises the following steps: firstly, carrying out one-time FPM iteration on a collected low-resolution image to obtain an initial amplitude diagram and an initial phase diagram, taking the two initial diagrams as the input of a WSTFPM network, and outputting the two initial diagrams as a high-resolution amplitude diagram and a high-resolution phase diagram; the WSTFPM network decomposes an initial amplitude diagram and an initial phase diagram into different frequency components by using wavelet transform, extracts local features and global features in combination with CNN and Transform, and finally reconstructs a high-resolution amplitude diagram and a high-resolution phase diagram. Experimental results show that compared with a traditional FPM reconstruction method based on iteration, WSTFPM consumes much less time while obtaining a good effect, and meanwhile, a good reconstruction effect can still be achieved under the condition that low-resolution images are few or system errors exist.

The application relates to a kind of quantitative imaging methods of living cells based on digital holographic microscopic sequential displacement aberration correction, and belongs to the field of optical measurement, comprising: collecting three holograms by sequentially displacing living cells; obtaining three original phase maps by phase demodulation; obtaining total mask map; sequentially displacing phase map in reverse direction; performing difference calculation to obtain global phase system aberration difference data; obtaining local system aberration difference data by using total mask map; performing difference processing on Chebyshev polynomial to obtain local polynomial difference data by using total mask map; fitting global system aberration by calculating corresponding coefficients from difference data; subtracting global system aberration from three original phase maps to obtain phase map of living cells after aberration correction. The application realizes high-precision quantitative phase imaging of living cells while retaining high-frequency information, has excellent displacement distance robustness, does not need to be equipped with high-precision displacement mechanism, and greatly reduces the hardware cost of measurement system.

A composite material gas cylinder layering defect displacement prediction method based on deep learning and laser shearing speckle interference comprises the following steps: constructing a training data set combining simulation data and experimental data, generating the simulation data based on a shearing speckle interference imaging principle, and combining the experimental data acquired by an experiment to predict the layering defect displacement of a composite material gas cylinder. Constructing a mixed data set containing a wrapped phase diagram and an out-of-plane displacement diagram; constructing a deep convolutional neural network fused with an attention mechanism, and extracting displacement features from high-frequency stripes: starting from an input layer, sequentially connecting an encoder path, a bottleneck layer, a decoder path and an output layer; constructing a composite loss function and training the network, and constructing a composite loss function comprising a pixel-level error constraint and a gradient consistency constraint; and utilizing the trained deep learning neural network to predict out-of-plane displacement response at the layering defect of the gas cylinder. According to the method, the problems of image distortion, data missing and the like caused by a traditional phase unwrapping algorithm are effectively solved, and the out-of-plane displacement field can be accurately, smoothly and continuously reconstructed.

A monolithic homodyne encoder is described herein. The monolithic homodyne encoder includes a diffractive optical slab. The diffractive optical slab includes a first side and a second side that are optically parallel to each other, a first set of phase maps on the first side of the diffractive optical slab that apply a spatial phase map to incoming light, and a second set of phase maps on the second side of the diffractive optical slab that directs the light to a component.

This application discloses a 3D imaging method and system based on structured light phase measurement, relating to the field of 3D imaging technology. The method includes: calibrating a structured light measurement system to obtain intrinsic and extrinsic parameters, and determining the effective measurement depth range and the corresponding effective absolute phase interval; controlling a projector to project a preset sinusoidal fringe pattern onto the measured scene, acquiring a deformed fringe image modulated by the surface of the measured object, and obtaining a wrapping phase map; calculating the initial fringe order of each pixel based on the effective measurement depth range using a frequency domain order-based fringe order no-neighborhood solution algorithm; performing no-neighborhood verification and error correction on the initial fringe order based on the effective absolute phase interval using an order self-verification and error correction algorithm to obtain the final fringe order; and calculating the absolute phase map of the entire field of view based on the wrapping phase map and the final fringe order, and converting the point cloud data. This application aims to solve the technical problem of existing spatial phase unfolding techniques relying on the continuity of adjacent pixels.

The application belongs to the technical field of optical three-dimensional measurement, and discloses a two-division iteration sub-pixel matching method and system for phase structured light three-dimensional measurement, which comprises the following steps: obtaining a phase map; performing legality marking and pixel-level initial matching on the phase map; determining a sub-pixel search area based on the pixel-level initial matching; and performing sub-pixel matching point search based on the sub-pixel search area by using a two-division iteration method to obtain a sub-pixel matching point. The application can improve the precision of binocular matching in phase structured light three-dimensional measurement, thereby improving the precision of three-dimensional reconstruction.

The invention discloses a multi-focus composite Fresnel phase diagram rapid generation and power equalization method and system for one-to-many free space laser communication. According to the method, aiming at a scene in which a plurality of user targets are located at different directional angles and different propagation distances, a focusing + directional single-beam phase is constructed for each target on the basis of analyzing a Fresnel zone lens phase and a linear tilt phase, and the phase is taken after complex field superposition is performed according to a preset power weight, so that the target target is obtained. A composite phase diagram for a phase-type spatial light modulator (SLM) is directly obtained. The power weight is preset according to a link budget or a task demand so as to realize on-demand distribution and equalization of multi-beam output power; and meanwhile, fixed phase bias can be introduced to each beam to suppress inter-beam interference fringes. According to the method, frame-by-frame iterative solution is not needed, the calculation complexity is low, and high-frame-rate and low-delay online updating is easy to realize.

The invention discloses a cell hologram automatic focusing and aberration compensation phase reconstruction method based on deep learning, and the method comprises the steps: obtaining a to-be-processed off-axis digital hologram of a cell sample based on an off-axis digital holographic microscopy system, and carrying out the preprocessing of an original hologram, and enhancing the data size; processing the holograms in batches by using a phase reconstruction method considering aberration compensation to generate corresponding phase diagrams, and forming a ''hologram-phase diagram'' image pair data set for model training; the image pair data set is used for training a pix2pix network model, the input of the model is a cell hologram, and the output of the model is a focusing phase diagram; according to the invention, automatic focusing and phase reconstruction can be simultaneously realized for a single hologram, a clear and distortionless in-focus phase diagram is directly output, the problem that only an object in a specific distance range can be clearly imaged is solved, and the method is suitable for cell observation, label-free pathological detection and dynamic analysis of living cells in the field of biomedicine.

The invention belongs to the technical field of optical processing and detection, and particularly relates to a CGH design method for detecting an axisymmetric complex curved surface, which is characterized in that a half-side phase diagram is binarized according to the characteristics of axisymmetric parts, and the calculation power is saved through symmetric complementation subsequently; accurately determining a stripe curve contour through a Newton iteration method; based on a chord height error control method, adaptive fast coding of CGH stripe positions is realized, and stripe coding accuracy and processing error evaluation consistency are improved. And a Python writing program is applied to complete the generation of a processing file GDSII, and the processing file GDSII is saved in a segmented manner, so that the requirement on the computer performance is reduced.

This invention discloses a method and system for de-flattening preprocessing, belonging to the field of radar imaging. The method includes: acquiring a main radar image and a secondary radar image, each containing several main image scattering points and several secondary image scattering points; calculating the secondary image scattering points corresponding to the main image scattering points to form several scattering point pairs; performing a flat-ground phase acquisition action to obtain an ideal flat-ground phase, thereby forming an ideal flat-ground phase map and completing the de-flattening preprocessing process. The flat-ground phase acquisition action includes: calculating the main image Doppler history and the secondary image Doppler history of the scattering point pairs; determining the main image focusing time that meets a preset time threshold to calculate the main image slant range, thereby determining the secondary image focusing time that meets the preset time threshold, and calculating the secondary image slant range based on the secondary image focusing time; and obtaining the ideal flat-ground phase of the scattering point pairs based on the main image slant range and the secondary image slant range. The de-flattening preprocessing method disclosed in this invention can effectively reduce the processing error of de-flattening preprocessing methods.