Target object three-dimensional imaging device and method in severe strong scattering medium environment

Abstract

The invention discloses a target object three-dimensional imaging device and method in a severe strong scattering medium environment. The target object three-dimensional imaging device comprises a transmitting module and a receiving module, the transmitting module comprises a digital projection device. The receiving module comprises a plane mirror, an imaging lens, a TIR prism, a DMD and a camera. A digital projection device emits structured light with phase information to a target object in a strong scattering medium environment, and reflected light of the structured light sequentially passes through a plane mirror, an imaging lens and a TIR prism and then reaches the surface of a DMD to be modulated to form modulated structured light; the camera captures the modulated structured light and transmits the modulated structured light to a computer for Fourier single-pixel imaging to obtain a two-dimensional image containing target phase information, and then the absolute phase of the target is obtained according to a phase unwrapping algorithm; according to system calibration parameters and the triangulation principle, the absolute phase is converted into three-dimensional point coordinates, and a reconstructed target three-dimensional image is obtained. According to the invention, the SPI can provide stronger anti-interference capability and higher imaging quality in a strong scattering environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical imaging and image processing, and in particular relates to a device and method for three-dimensional imaging of a target object in a harsh strong scattering medium environment. Background Art

[0002] In harsh environments with strong scattering media, the ambient light is insufficient. What is more serious is that strong scattering media usually cause a large amount of backscattered light to be generated, which will be received by the imaging sensor, increase noise and reduce the signal strength, resulting in blurred and distorted imaging. Therefore, there are imaging difficulties in the atmospheric environment under haze weather or in aerosols, smoke and underwater environments in various industrial processes. In addition, marine resource exploration, biological population monitoring, underwater target detection and environmental monitoring are of great importance to human survival and development. Therefore, three-dimensional imaging in harsh environments with strong scattering is of great significance. In recent years, the development of computational optical imaging technology and the emergence of high-precision wavefront modulation devices such as spatial light modulators (SLMs) and digital micromirror devices (DMDs) have promoted the development of related research on scattering imaging. New optical technologies such as optical coherence tomography, optical phase conjugation, wavefront feedback regulation, optical transmission matrix, and speckle autocorrelation have emerged. These technologies have achieved good results in overcoming the influence of scattering media on imaging effects. However, the disadvantages of these methods are that they are easily affected by environmental conditions, have high complexity, and are sensitive to changes in scattering media. Therefore, in harsh and strongly scattering medium environments, the problems of high signal-to-noise ratio (SNR) and anti-scattering are still difficult problems that need to be solved urgently in current technologies. Summary of the invention

[0003] The present invention designs a target object three-dimensional imaging device and imaging method suitable for low light and harsh strong scattering medium conditions, which can provide stronger anti-interference ability and higher imaging quality.

[0004] Based on the above problems, the present invention adopts the following technical solutions:

[0005] A three-dimensional imaging device for a target object in a harsh strong scattering medium environment, comprising: a transmitting module and a receiving module;

[0006] The transmitting module includes a digital projection device, and the receiving module includes a plane mirror, an imaging lens, a TIR prism, a DMD and a camera;

[0007] The digital projection device emits structured light with phase information to a target object in a strong scattering medium environment, and the reflected light passes through a plane mirror, an imaging lens, and a TIR prism in sequence, and is projected onto the DMD surface for modulation to form modulated structured light;

[0008] The camera captures the modulated structured light and transmits it to a computer for Fourier single-pixel imaging; a two-dimensional image containing target phase information is obtained, and then the absolute phase of the target is obtained according to a phase unwrapping algorithm. Based on the principle of triangulation and combined with the calibration parameters of the three-dimensional imaging device, the absolute phase is converted into three-dimensional point coordinates to obtain a reconstructed three-dimensional image of the target.

[0009] Furthermore, the DMD is preloaded with a series of Fourier speckle pattern sequences to modulate the structured light reflected by the target object.

[0010] On the other hand, the present invention provides a method for three-dimensional imaging of a target object in a harsh strong scattering medium environment, comprising the following steps:

[0011] Step S1, calibrating the three-dimensional imaging device to obtain calibration parameters of the three-dimensional imaging device;

[0012] Step S2, pre-loading a series of Fourier speckle patterns into the DMD of the three-dimensional imaging device;

[0013] Step S3, modulating the structured light reflected by the target object based on a series of Fourier speckle patterns pre-loaded by the DMD to obtain a reconstructed two-dimensional image;

[0014] Step S4, based on the two-dimensional image reconstructed in step S3 and in combination with a phase unwrapping algorithm, calculating the absolute phase of the target object;

[0015] Step S5, based on the triangulation principle and in combination with the calibration parameters of the three-dimensional imaging device, the absolute phase is converted into three-dimensional point coordinates to obtain a reconstructed target three-dimensional image.

[0016] Furthermore, the step S1 includes calibration of the spatial positions of the camera and the DMD, calibration of the internal and external parameters of the DMD, and calibration of the internal and external parameters of the digital projection device.

[0017] Furthermore, in step S2, a series of Fourier speckle patterns P are loaded. φ (x,y;f x ,f y )for:

[0018] P φ (x,y;f x ,f y )=a+b·cos(2πf x x+2πf y y+φ)

[0019] Where (x, y) is the two-dimensional Cartesian coordinate of the modulation pattern, (f x ,f y) is the spatial frequency, a is the average intensity of the image, b is the amplitude of the modulation pattern, and φ is the initial phase.

[0020] Furthermore, the step S3 comprises:

[0021] Step S31, calculating the total light intensity of the modulation area based on loading a series of Fourier speckle patterns;

[0022] Step S32, calculating the total response of the camera collecting the reflected light reaching its photosensitive surface based on the total light intensity of the modulation area;

[0023] Step S33, estimating the frequency spectrum value of the target object at the spatial frequency;

[0024] Step S34: acquiring a reconstructed two-dimensional image based on the frequency spectrum value of the target object at the spatial frequency and the Fourier single-pixel imaging algorithm.

[0025] Furthermore, the total light intensity E in the modulation area φ (f x ,f y )for:

[0026]

[0027] Where Ω is the modulation area and R(x,y) is the reflectivity of the target.

[0028] Furthermore, the total response of the reflected light D φ (f x ,f y )for:

[0029] D φ (f x ,f y )=D n +kE φ (f x ,f y )

[0030] Where D n is the response to ambient light, and k is the intensity modulation coefficient.

[0031] Furthermore, the spectrum value T(f x ,f y )for:

[0032] T(f x ,f y )=[D 0 (f x ,f y )-D π (f x ,f y)]+j[D π / 2 (f x ,f y )-D 3π / 2 (f x ,f y )]

[0033] Where D 0 (f x ,f y )、D π / 2 (f x ,f y ), D π (f x ,f y )、D 3π / 2 (f x ,f y ) represent the total response when the phase φ is 0, π / 2, π and 3π / 2 respectively, and j represents the imaginary unit.

[0034] Furthermore, the reconstructed two-dimensional image I(x,y) is expressed as:

[0035] I(x,y)=F -1 {T(f x ,f y )}

[0036] =F -1 {[D 0 (f x ,f y )-D π (f x ,f y )]+j[D π / 2 (f x ,f y )-D 3π / 2 (f x ,f y )]}

[0037] =2bk·R(x,y)

[0038] ∝R(x,y)

[0039] Where F -1 {T(f x ,f y )} represents the reconstructed two-dimensional image as the spectrum value T(f x ,f y ) is the inverse Fourier transform function of .

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The present invention designs a three-dimensional imaging device suitable for low-light or harsh strong scattering scenes, and proposes a three-dimensional Fourier single pixel imaging (3D-FSPI) method, which can reconstruct the three-dimensional image of the measured object in a harsh strong scattering environment at a low sampling rate. In a specific embodiment, taking an underwater harsh scattering scene as an example, the proposed device and method realize for the first time the reconstruction of the three-dimensional morphology of an underwater object of medium complexity in a water environment with a sampling rate of only 15% and high turbidity (50NTU). The 3D-FSPI method uses the mPMPC method to calibrate system parameters, uses FSPI to reconstruct a two-dimensional deformed fringe pattern, uses a multi-frequency heterodyne method to calculate the absolute phase of the object, and uses the triangulation principle to obtain the three-dimensional information of the object. At the same time, it is also compared with the SPI (single pixel imaging) method based on cake cutting Hadamard speckle and random Hadamard speckle, which further verifies the superiority of our method in physical experiments. The 3D-FSPI method has shown strong visual reconstruction capabilities in both two-dimensional image reconstruction and three-dimensional object imaging within medium and short distances, for example, it has excellent visual effects in both two-dimensional images and three-dimensional morphology. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a schematic diagram of the imaging device of the present invention;

[0043] Figure 2 A schematic diagram of an experimental hardware device of an imaging device according to an embodiment of the present invention;

[0044] Figure 3 A schematic diagram of a process of adjusting spatial position and mapping pixels according to an embodiment of the present invention;

[0045] Figure 4 This is a comparison diagram of images reconstructed using different speckles and sampling rates under high turbidity according to an embodiment of the present invention;

[0046] Figure 5 The PSNR and SSIM curves of the image reconstructed under high turbidity according to the embodiment of the present invention;

[0047] Figure 6 It is a schematic diagram of the absolute phase and corresponding single-pixel three-dimensional reconstruction results using different sampling rates and reconstruction methods under high turbidity according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to facilitate those skilled in the art to understand and implement the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and the present embodiment. It should be understood that the implementation examples described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0049] Example 1

[0050] like Figure 1 As shown, the present invention provides a three-dimensional imaging device for a target object in a harsh strong scattering medium environment:

[0051] Including: a transmitting module and a receiving module;

[0052] The transmitting module includes a digital projection device, and the receiving module includes a plane mirror, an imaging lens, a TIR prism (total internal reflection prism), a DMD and a camera;

[0053] The digital projection device emits structured light with phase information to a target object in a strong scattering medium environment, and the reflected light passes through a plane mirror, an imaging lens, and a TIR prism in sequence, and is projected onto the DMD surface for modulation to form modulated structured light;

[0054] The camera captures the modulated structured light and transmits it to a computer for Fourier single pixel imaging (FSPI); a two-dimensional image containing target phase information is obtained, and then the absolute phase of the target is obtained according to a phase unwrapping algorithm. Based on the principle of triangulation and combined with the calibration parameters of the three-dimensional imaging device, the absolute phase is converted into three-dimensional point coordinates to obtain a reconstructed three-dimensional image of the target.

[0055] The DMD is preloaded with a series of Fourier speckle pattern sequences to modulate the structured light reflected by the target.

[0056] like Figure 2 As shown, in this embodiment, the digital projection device is a digital projector, which emits structured light with phase information, and the structured light takes sinusoidal stripes as an example; the target object is placed in a water tank containing calcium carbonate suspension to construct a strong scattering medium environment.

[0057] In this embodiment, the camera can be used as a common camera for the calibration process of the imaging device of the present invention, and can also be used as a bucket detector for receiving modulated light from the DMD to facilitate subsequent FSPI reconstruction.

[0058] Example 2

[0059] In this embodiment, a set of sinusoidal fringes emitted by the projector will be deformed by the surface of the object, and the imaging lens projects the object and the deformed fringes onto the DMD surface. Both the plane mirror and the TIR prism in the path help to deflect the light path, and the TIR prism can also minimize the loss of light energy. Then, a series of Fourier speckle pattern sequences are loaded on the DMD to modulate the reflected light from the object, and the modulated light is captured by the camera sensor and transmitted to the computer. Here, the camera can also act as a bucket detector to simplify the experimental setup and reduce costs. The received light intensity information is used for FSPI reconstruction. It is worth noting that the reconstructed image contains the fringe information modulated by the surface of the object, and these distorted fringe images can be used to calculate the absolute phase of the object. Finally, the absolute phase is converted into spatial point coordinates using the system calibration parameters and the principle of triangulation, thereby obtaining a three-dimensional image reconstruction of the target.

[0060] The specific steps include:

[0061] Step S1, calibrating the three-dimensional imaging device to obtain calibration parameters of the three-dimensional imaging device;

[0062] In this embodiment, the spatial position between the CMOS camera and the DMD is adjusted before obtaining the calibration parameters of the three-dimensional imaging device. The DMD is rotated 45 degrees to ensure that the incident light and the outgoing light are on the same horizontal plane. The camera also needs to be rotated by the same angle to meet the condition that the camera frame is parallel to the micromirror array. In addition, a six-degree-of-freedom displacement platform is used to fine-tune the position of the camera to ensure that the DMD is centered within the camera frame. Figure 3 As shown in (a)-(c).

[0063] In this embodiment, step S1 includes calibration of the spatial position of the camera and the DMD, calibration of the internal and external parameters of the DMD, and calibration of the internal and external parameters of the digital projection device, specifically:

[0064] Solve the mapping between the CMOS camera pixel coordinate system and the DMD micromirror coordinate system. Assume that the coordinates of the feature points on the image loaded on the DMD are (u DMD ,v DMD ), the corresponding feature point on the image received by CMOS is (u CMOS ,v CMOS ),like Figure 3 As shown in (d)-(e), the mapping relationship between the two coordinates can be approximated by the following formula.

[0065]

[0066] where a 0 -a 4 and b 0 -b 4is the distortion coefficient, which can be solved by the method of undetermined coefficients according to the coordinates of the feature points.

[0067] Calibration of the internal and external parameters of the DMD pseudo camera. After the above pixel mapping, the DMD can be equivalent to the image detector array used for imaging, so the image captured by the camera can also be regarded as the image taken by the DMD as a pseudo camera. However, during the calibration process, it is not necessary to convert all the calibration images in the camera coordinate system to the DMD coordinate system, but only the extracted feature point coordinates need to be converted, which greatly reduces the computational complexity. Then, the internal parameter matrix and external parameter matrix of the DMD are obtained based on Zhang's calibration method.

[0068] Calibration of internal and external parameters of the projector pseudo camera. In the structured light 3D imaging model, the phase information of the projector coordinate system is known. By projecting the sinusoidal fringes onto the calibration board and performing phase solution, the coordinates of the feature points on the calibration board can be associated with the phase information. Therefore, the projector can also be regarded as a pseudo camera. The corresponding relationship is expressed by the following equation:

[0069]

[0070]

[0071] Where (u pro ,v pro ) represents the coordinates of the feature point in the projector coordinate system, Φ v (u DMD ,v DMD ) and Φ h (u DMD ,v DMD ) represent the absolute phase values ​​of the feature points in the horizontal and vertical directions, respectively. In addition, W and H represent the resolution of the DMD image in the horizontal and vertical directions, and N v and N h Represents the number of fringes in the corresponding direction. After obtaining the coordinates of the feature points in the projector coordinate system, the internal parameter matrix and external parameter matrix of the projector are obtained based on Zhang's calibration method. At this point, the calibration of the entire system is completed.

[0072] Step S2, pre-loading a series of Fourier speckle patterns into the DMD of the three-dimensional imaging device;

[0073] The received light intensity information is used for image reconstruction through the FSPI algorithm. The specific method is as follows: A series of Fourier speckle patterns are generated by the following formula:

[0074] P φ (x,y;f x ,f y )=a+b·cos(2πf x x+2πfy y+φ)

[0075] Where (x, y) is the two-dimensional Cartesian coordinate of the modulation pattern, (f x ,f y ) is the spatial frequency, a is the average intensity of the image, b is the amplitude of the modulation pattern, and φ is the initial phase.

[0076] Step S3, modulating the structured light reflected by the target object based on a series of Fourier speckle patterns pre-loaded by the DMD to obtain a reconstructed two-dimensional image;

[0077] Step S3 includes:

[0078] Step S31, calculating the total light intensity of the modulation area based on loading a series of Fourier speckle patterns;

[0079] The total light intensity E in the modulation area φ (f x ,f y )for:

[0080]

[0081] Where Ω is the modulation area and R(x,y) is the reflectivity of the target.

[0082] Step S32, calculating the total response of the camera collecting the reflected light reaching its photosensitive surface based on the total light intensity of the modulation area;

[0083] The total response of reflected light D φ (f x ,f y )for:

[0084] D φ (f x ,f y )=D n +kE φ (f x ,f y )

[0085] Where D n is the response to ambient light, and k is the intensity modulation coefficient, which depends on the size and position of the detector.

[0086] Step S33, estimating the frequency spectrum value of the target object at the spatial frequency;

[0087] The spectrum value of the target at the spatial frequency T(f x ,f y )for:

[0088] T(f x ,f y )=[D0 (f x ,f y )-D π (f x ,f y )]+j[D π / 2 (f x ,f y )-D 3π / 2 (f x ,f y )]

[0089] Where D 0 (f x ,f y )、D π / 2 (f x ,f y )、D π (f x ,f y )、D 3π / 2 (f x ,f y ) represent the total response when the phase φ is 0, π / 2, π and 3π / 2, respectively, and j represents the imaginary unit. In FSPI, the spatial spectrum of the target can be obtained by a four-step phase shifting method, where the four speckle patterns have the same spatial frequency (f x ,f y ), but the phase is different. The phase shift between two adjacent speckle patterns is a constant π / 2. When the phase φ is 0, π / 2, π and 3π / 2, the corresponding measurement values ​​of the camera detector are D 0 , D π / 2 , D π and D 3π / 2 .

[0090] Step S34: acquiring a reconstructed two-dimensional image based on the frequency spectrum value of the target object at the spatial frequency and the Fourier single-pixel imaging algorithm.

[0091] Since the gray value I(x, y) of the target image is proportional to the reflectivity R(x, y), the reconstructed two-dimensional image I(x, y) is expressed as:

[0092] I(x,y)=F -1 {T(f x ,f y )}

[0093] =F -1 {[D 0 (f x ,f y )-D π (f x ,f y )]+j[D π / 2 (fx ,f y )-D 3π / 2 (f x ,f y )]}

[0094] =2bk·R(x,y)

[0095] ∝R(x,y)

[0096] Where F -1 {T(f x ,f y )} represents the reconstructed two-dimensional image as the spectrum value T(f x ,f y ) is the inverse Fourier transform function of .

[0097] Step S4, calculating the absolute phase of the target object using a multi-frequency heterodyne method based on the two-dimensional image reconstructed in step S3;

[0098] Step S5, based on the triangulation principle and in combination with the calibration parameters of the three-dimensional imaging device, the absolute phase is converted into three-dimensional point coordinates to obtain a reconstructed target three-dimensional image.

[0099] In this embodiment, a designed underwater Fourier single-pixel three-dimensional imaging device is used to collect the required data.

[0100] The collected light intensity data is processed using the FSPI algorithm. Figure 4 Shown are images reconstructed using different methods and different sampling rates under high turbidity.

[0101] The restored data is quantitatively evaluated. Two performance evaluation indicators, peak signal-to-noise ratio (PSNR) and structural similarity (SSIM), are introduced. PSNR is based on the pixel error between images, and SSIM evaluates image quality by considering the brightness, contrast, and structural information of the image.

[0102]

[0103]

[0104]

[0105] Among them MAX I is the maximum grayscale value of the image, MSE is the mean square error of the image, m×n is the size of the image, I(i,j), O(i,j) are the original image and the reconstructed image respectively. i,j are the horizontal and vertical coordinates of the image respectively. μ X ,μ Y represents the mean of the image, σ 2 X,σ 2 Y represents the variance of the image, σ XY represents the covariance of the image. C 1 ,C 2 is a constant to avoid division by 0. Figure 5 As shown, the PSNR and SSIM of images restored by different methods.

[0106] Using the reconstructed two-dimensional deformed fringe image, the phase distribution of the object is calculated using the multi-frequency heterodyne method. The results are as follows Figure 6 shown.

[0107] Reconstruction of the three-dimensional shape of the object. Combining the calibration parameters and the phase distribution of the object, the three-dimensional surface shape of the object is obtained using triangulation. The results are as follows: Figure 6 shown.

[0108] The above is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present application should be covered within the protection scope of the present application.

[0109] It should be understood that parts not elaborated in detail in this specification belong to the prior art.

[0110] It should be understood that the above description of the preferred embodiment is relatively detailed and cannot be regarded as limiting the scope of patent protection of the present invention. Under the enlightenment of the present invention, ordinary technicians in this field can also make substitutions or modifications without departing from the scope of protection of the claims of the present invention, which all fall within the scope of protection of the present invention. The scope of protection requested for the present invention shall be based on the attached claims.

Claims

1. A three-dimensional imaging device for a target object in a harsh strong scattering medium environment, characterized in that: include: Transmitter module and receiver module; The transmitting module includes a digital projection device, and the receiving module includes a plane mirror, an imaging lens, a TIR prism, a DMD and a camera; The digital projection device emits structured light with phase information to a target object in a strong scattering medium environment, and the reflected light passes through a plane mirror, an imaging lens, and a TIR prism in sequence, and is projected onto the DMD surface for modulation to form modulated structured light; The camera captures the modulated structured light and transmits it to a computer for Fourier single-pixel imaging; a two-dimensional image containing target phase information is obtained, and then the absolute phase of the target is obtained according to a phase unwrapping algorithm. Based on the principle of triangulation and combined with the calibration parameters of the three-dimensional imaging device, the absolute phase is converted into three-dimensional point coordinates to obtain a reconstructed three-dimensional image of the target.

2. The three-dimensional imaging device for a target object in a harsh strong scattering medium environment according to claim 1, characterized in that: The DMD is preloaded with a series of Fourier speckle pattern sequences to modulate the structured light reflected by the target object.

3. A method for three-dimensional imaging of a target object in a harsh strong scattering medium environment, characterized in that: The three-dimensional imaging device according to claim 1 or 2 is used to perform three-dimensional imaging, comprising the following steps: Step S1, calibrating the three-dimensional imaging device to obtain internal and external calibration parameters of the three-dimensional imaging device; Step S2, pre-loading a series of Fourier speckle patterns into the DMD of the three-dimensional imaging device; Step S3, modulating the structured light reflected by the target object based on a series of Fourier speckle patterns pre-loaded by the DMD to obtain a reconstructed two-dimensional image; Step S4, based on the two-dimensional image reconstructed in step S3 and in combination with a phase unwrapping algorithm, calculating the absolute phase of the target object; Step S5, based on the triangulation principle and in combination with the calibration parameters of the three-dimensional imaging device, the absolute phase is converted into three-dimensional point coordinates to obtain a reconstructed target three-dimensional image.

4. The method for three-dimensional imaging of a target object in a harsh strong scattering medium environment according to claim 3, characterized in that: The step S1 includes calibration of the spatial positions of the camera and the DMD, calibration of the internal and external parameters of the DMD, and calibration of the internal and external parameters of the digital projection device.

5. The method for three-dimensional imaging of a target object in a harsh strong scattering medium environment according to claim 3, characterized in that: In step S2, a series of Fourier speckle patterns P are loaded. φ (x,y;f x ,f y )for: P φ (x,y;f x ,f y )=a+b·cos(2πf x x+2πf y y+φ) Where (x, y) is the two-dimensional Cartesian coordinate of the modulation pattern, (f x ,f y ) is the spatial frequency, a is the average intensity of the image, b is the amplitude of the modulation pattern, and φ is the initial phase.

6. The method for three-dimensional imaging of a target object in a harsh strong scattering medium environment according to claim 5, characterized in that: The step S3 comprises: Step S31, calculating the total light intensity of the modulation area based on loading a series of Fourier speckle patterns; Step S32, calculating the total response of the camera collecting the reflected light reaching its photosensitive surface based on the total light intensity of the modulation area; Step S33, estimating the frequency spectrum value of the target object at the spatial frequency; Step S34: acquiring a reconstructed two-dimensional image based on the frequency spectrum value of the target object at the spatial frequency and the Fourier single-pixel imaging algorithm.

7. The method for three-dimensional imaging of a target object in a harsh strong scattering medium environment according to claim 6, characterized in that: The total light intensity E in the modulation area φ (f x ,f y )for: Where Ω is the modulation area and R(x,y) is the reflectivity of the target.

8. The method for three-dimensional imaging of a target object in a harsh strong scattering medium environment according to claim 6, characterized in that: The total response of reflected light D φ (f x ,f y )for: D φ (f x ,f y )=D n +kE φ (f x ,f y ) Where D n is the response to ambient light, and k is the intensity modulation coefficient.

9. The method for three-dimensional imaging of a target object in a harsh strong scattering medium environment according to claim 6, characterized in that: The spectrum value of the target at the spatial frequency T(f x ,f y )for: T(f x ,f y )=[D0(f x ,f y )-D π (f x ,f y )]+j[D π / 2 (f x ,f y )-D 3π / 2 (f x ,f y )] In the formula, D0(f x ,f y )、D π / 2 (f x ,f y )、D π (f x ,f y )、D 3π / 2 (f x ,f y ) represent the total response when the phase φ is 0, π / 2, π and 3π / 2 respectively, and j represents the imaginary unit.

10. The method for three-dimensional imaging of a target object in a harsh strong scattering medium environment according to claim 6, characterized in that: The reconstructed two-dimensional image I(x,y) is expressed as: I(x,y)=F -1 {T(f x ,f y )} =F -1 {[D0(f x ,f y )-D π (f x ,f y )]+j[D π / 2 (f x ,f y )-D 3π / 2 (f x ,f y )]} =2bk·R(x,y) ∝R(x,y) Where F -1 {T(f x ,f y )} represents the reconstructed two-dimensional image as the spectrum value T(f x ,f y ) is the inverse Fourier transform function of .

Images