Polarized illumination based tomographic imaging method, apparatus and device for multilayer target

Abstract

The application provides a multi-layer object tomography method, device and equipment based on polarized illumination. The method comprises the following steps: obtaining a pair of orthogonal polarization images; establishing a current Jones matrix based on a current optical axis direction and a current phase delay, and establishing a Jones vector by using an initial polarized incident light corresponding to the pair of orthogonal polarization images; establishing a current forward propagation model by using the current Jones matrix and the Jones vector; performing parameter update processing on the current forward propagation model based on the pair of orthogonal polarization images to obtain updated light field data; and performing reverse propagation processing on the updated light field data to obtain a post-layer light field. In the application, the forward propagation model is established based on the polarization characteristics of the target scattering light field, and the reverse update processing is continuously performed on the Jones matrix through the iterative process of the reverse propagation, so that the parallel reconstruction of multiple target information is finally realized, and the multi-layer object tomography result is obtained. Since the calibration of the hardware device and the illumination state is not required, the efficiency of the tomography is improved.

Description

Technical Field

[0001] This invention relates to the field of computational imaging technology, and specifically to a multi-layer target tomography method, apparatus, and device based on polarized illumination. Background Technology

[0002] Existing deep multilayer microscopy imaging techniques enable high-speed parallel imaging and sensing of multiple targets. This technique establishes sample constraints on the light field interpretation process by varying the incident light illumination angle, modeling different target layers as different coded surfaces and reconstructing them. However, this technique relies on variations in the incident light illumination angle. This not only necessitates the introduction of mechanical moving parts or the use of LEDs to provide illumination at different angles during experiments, but also requires calculation and calibration of the illumination light state during reconstruction, thus increasing the complexity of the solution process.

[0003] For most biological tissues and crystalline materials, their anisotropic structure causes changes in the polarization information carried by light as it propagates through the sample (target). After being modulated by the sample structure and birefringence properties, the emitted scattered light field highlights its polarization characteristics. By measuring and interpreting the polarization information of this scattered light field, information about the sample can be obtained. Therefore, if we utilize the modulation effect of the sample on the polarization information of the scattered light field to analyze the change process of polarization information when the light field passes through multiple targets, establish new sample constraints, and achieve light field information modeling under single-angle illumination, it will greatly simplify the complexity of the experimental system and improve imaging efficiency.

[0004] Therefore, improving the structure and imaging process of existing imaging systems has significant application prospects and value for improving detection efficiency. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a method, apparatus, and device for multi-layer target tomography based on polarized illumination.

[0006] The technical problem to be solved by this invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a multi-layer target tomography method based on polarized illumination, comprising:

[0008] S101. Obtain an orthogonal polarization image pair; the first polarization image and the second polarization image in the orthogonal polarization image pair are a pair of polarization images acquired by a multi-layer target tomography device under fixed polarization illumination conditions, and the orthogonal polarization image pair contains multiple target information; the multiple target information contains preset coding layer information.

[0009] S102. Establish the current Jones matrix based on the current optical axis direction and the current phase delay, and use the orthogonal polarization image to establish the Jones vector for the corresponding initial polarized incident light.

[0010] S103. Establish the current forward propagation model using the current Jones matrix and Jones vector;

[0011] S104. Based on the orthogonal polarization image pair, perform parameter update processing on the current forward propagation model to obtain updated light field data;

[0012] S105. Perform backpropagation processing on the updated light field data to obtain the back-layer light field;

[0013] S106. Based on the back-layer optical field, update the current optical axis direction and current phase delay in S102 to obtain the updated optical axis direction and updated phase delay. Use the updated optical axis direction as the current optical axis direction in S102 and the updated phase delay as the current phase delay in S102.

[0014] S107. Repeat S102-S106 until the current Jones matrix corresponding to each layer of the target in the orthogonal polarization image pair satisfies the preset convergence condition.

[0015] S108. When S107 is true, the updated optical axis direction and updated phase delay corresponding to the most recent execution of S106 are used as the result of multi-layer target tomography.

[0016] Optionally, the current Jones matrix is ​​represented as:

[0017]

[0018] Among them, Js t Let θ represent the current Jones matrix of the target at layer t, θ represent the current optical axis direction, δ represent the current phase delay, i represent the imaginary unit, and T represent the total number of layers of the target.

[0019] Jones vector representation is:

[0020]

[0021] Among them, E j Let E represent the Jones vector under the j-th illumination condition. x E represents the initial polarized incident light in the x-axis component of an orthogonal polarization image. y denoted as the initial polarized incident light in the y-axis component of the orthogonal polarization image, and J represents the total number of illumination conditions.

[0022] Optionally, the current forward propagation model is represented as:

[0023]

[0024] in, This represents the current light field data of the target at layer T under the j-th illumination condition, PSF. free (d1) represents the free-space propagation kernel at a propagation distance d1, where d1 represents the distance between the first-layer target and the second-layer target, and PSF. free (d T-1 ) represents the propagation distance d T-1 The free-space propagation kernel under d T-1 This represents the distance between the target at layer T-1 and the target at layer T.

[0025] Optionally, the current forward propagation model is updated based on the orthogonal polarization image pair to obtain updated optical field data, including:

[0026] Based on the amplitude values ​​corresponding to the orthogonal polarization images and the current forward propagation model, the updated optical field data is calculated using the following formula:

[0027]

[0028] I represents the Jones vector component in the k-th row corresponding to the updated light field data of the target at layer T under the j-th illumination condition. jk This represents the Jones vector component in the k-th row corresponding to the light intensity value of the orthogonal polarization image under the j-th illumination condition. Let I represent the Jones vector component in the k-th row corresponding to the current light field data of the target at layer T under the j-th illumination condition, where I jk The intensity value is obtained based on the orthogonal polarization image.

[0029] Alternatively, the back-layer light field can be represented as:

[0030]

[0031] in, Let $\frac{ ... This represents the Jones vector component in the k-th row corresponding to the updated light field data of the target at layer t under the j-th illumination condition, PSF. free (-d t ) represents the propagation distance -d t The free-space propagation kernel under d t This represents the distance between the target at layer t and the target at layer t+1.

[0032] Optionally, the current optical axis direction and current phase delay in S102 are updated based on the back-layer optical field to obtain the updated optical axis direction and updated phase delay. The updated optical axis direction is used as the current optical axis direction in S102, and the updated phase delay is used as the current phase delay in S102. This includes:

[0033] Using the back-layer optical field, the current optical axis direction, and the current phase delay, the following formula is used for updating to obtain the non-complex increment of the current optical axis direction and the non-complex increment of the current phase delay:

[0034]

[0035] Let $\frac{ ... Indicates the state before the update Let represent the partial derivative expression of the element in the k-th row and u-th column of the current Jones matrix of the target at layer t with respect to θ. Let represent the partial derivative of the element in row k and column u of the current Jones matrix of the target at layer t with respect to δ, where Δθ represents the non-complex increment of the current optical axis direction, and Δδ represents the non-complex increment of the current phase delay. This represents the u-th Jones vector component of the current light field data of the target at layer t-1 under the j-th illumination condition;

[0036] Based on the non-complex increment of the current optical axis direction and the non-complex increment of the current phase delay, the updated optical axis direction and the updated phase delay are calculated using the following formula:

[0037] θ' = θ + α·Δθ;

[0038] δ' = δ + α·Δδ;

[0039] θ' represents the updated optical axis direction, δ' represents the updated phase delay, θ represents the current optical axis direction, δ represents the current phase delay, and α represents the step size coefficient;

[0040] The updated optical axis direction is used as the current optical axis direction in S102, and the updated phase delay is used as the current phase delay in S102.

[0041] Optionally, the preset convergence condition is that the non-complex increment corresponding to the updated optical axis direction and the non-complex increment corresponding to the updated phase delay are both less than a preset threshold.

[0042] In a second aspect, the present invention provides a multi-layer target tomography imaging device based on polarized illumination, comprising: an acquisition unit, a matrix establishment unit, an update unit, a processing unit, an iteration unit, and a judgment unit;

[0043] The acquisition unit is used to: acquire orthogonal polarization image pairs; the first polarization image and the second polarization image in the orthogonal polarization image pair are a pair of polarization images acquired by a multi-layer target tomography device under fixed polarization illumination conditions, and the orthogonal polarization image pair contains multiple target information; the multiple target information contains preset coding layer information;

[0044] The matrix establishment unit is used to: establish the current Jones matrix based on the current optical axis direction and the current phase delay, and establish the Jones vector for the corresponding initially polarized incident light using an orthogonal polarization image;

[0045] The current forward propagation model is established by combining the current Jones matrix and Jones vector;

[0046] The update unit is used to: perform parameter update processing on the current forward propagation model based on orthogonal polarization image pairs to obtain updated light field data;

[0047] The processing unit is used to: perform backpropagation processing on the updated light field data to obtain the back-layer light field;

[0048] The update unit is also used to: perform update processing based on the current optical axis direction and current phase delay of the back-layer optical field to obtain the updated optical axis direction and updated phase delay, and use the updated optical axis direction as the current optical axis direction in the matrix building unit, and use the updated phase delay as the current phase delay in the matrix building unit;

[0049] The iteration unit is used to control the repeated execution of the matrix building unit, update unit and processing unit until the current Jones matrix corresponding to each layer of the target in the orthogonal polarization image pair satisfies the preset convergence condition.

[0050] The judgment unit is used to: when the preset convergence condition of the iteration unit is met, take the updated optical axis direction and updated phase delay of the most recent update in the update unit as the result of multi-layer target tomography.

[0051] Thirdly, the present invention provides a multi-layer target tomography device based on polarized illumination, the multi-layer target tomography device based on polarized illumination comprising: a first unit, a second unit and a third unit arranged sequentially.

[0052] The first unit includes: a coherent light source, a collimating lens, and a first polarization modulation device arranged sequentially; the center of the coherent light source is aligned with the center of the collimating lens;

[0053] The second unit is equipped with a second polarization modulation device; multiple targets to be imaged are stacked axially between the first unit and the second polarization modulation device, and the centers of the multiple targets to be imaged are all aligned with the center of the collimating lens; the last layer of the multiple targets to be imaged is set as an encoding layer.

[0054] The third unit includes: detectors and computing devices arranged sequentially; the distance between the edge of the coding layer and the detector is 1-5mm.

[0055] Fourthly, the present invention provides a multi-layer target tomography device based on polarized illumination, comprising: a processor, a storage medium and a bus, wherein the storage medium stores machine-readable instructions executable by the processor, and when the multi-layer target tomography device based on polarized illumination is running, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the multi-layer target tomography method based on polarized illumination as described in the first aspect above.

[0056] This invention provides a method, apparatus, and device for multi-layer target tomography based on polarized illumination. The method includes: S101, acquiring orthogonal polarization image pairs; the first and second polarization images in the orthogonal polarization image pairs are a pair of polarization images acquired using a multi-layer target tomography device under fixed polarized light illumination conditions, and the orthogonal polarization image pairs contain information about multiple targets; S102, establishing a current Jones matrix based on the current optical axis direction and current phase delay, and establishing a Jones vector using the initial polarized incident light corresponding to the orthogonal polarization image pairs; S103, jointly establishing a current forward propagation model using the current Jones matrix and Jones vector; S104, performing parameter update processing on the current forward propagation model based on the orthogonal polarization image pairs to obtain an updated light field. Data; S105, perform backpropagation processing on the updated optical field data to obtain the back-layer optical field; S106, update the current optical axis direction and current phase delay in S102 based on the back-layer optical field to obtain the updated optical axis direction and updated phase delay, and use the updated optical axis direction as the current optical axis direction in S102, and the updated phase delay as the current phase delay in S102; S107, repeat S102-S106 until the current Jones matrix corresponding to each layer of target in the orthogonal polarization image pair satisfies the preset convergence condition; S108, when S107 is true, use the updated optical axis direction and updated phase delay corresponding to the most recent execution of S106 as the multi-layer target tomography imaging result. In this invention, a pair of polarized images acquired under polarized illumination conditions are used as the starting point to effectively separate the target information of each single layer from the aliased image information of multiple targets. Specifically, a forward propagation model is established based on the polarization characteristics of the target's scattered light field, and the Jones matrix is ​​continuously updated through a backward propagation iterative process. Ultimately, parallel reconstruction of multiple target information under single-angle illumination is achieved, resulting in multi-layer target tomography. Since this invention does not require calibration of hardware equipment and illumination conditions, the efficiency of multi-layer target tomography is improved.

[0057] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0058] Figure 1 A schematic flowchart of a multi-layer target tomography method based on polarized illumination provided in an embodiment of the present invention;

[0059] Figure 2 A flowchart illustrating a multi-layer target tomography method based on polarized illumination, provided in an embodiment of the present invention;

[0060] Figure 3 A schematic diagram of a multi-layer target tomography imaging device based on polarized illumination provided in an embodiment of the present invention;

[0061] Figure 4 A schematic diagram of a multi-layer target tomography imaging device based on polarized illumination provided in an embodiment of the present invention;

[0062] Figure 5 This is a schematic diagram of a multi-layer target tomography device based on polarized illumination, provided as an embodiment of the present invention. Detailed Implementation

[0063] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0064] To improve the efficiency of multi-layer target tomography, this invention provides a multi-layer target tomography method based on polarized illumination. Figure 1 This is a schematic flowchart illustrating a multi-layer target tomography method based on polarized illumination, provided as an embodiment of the present invention. Figure 1 As shown, it includes:

[0065] S101. Obtain orthogonal polarization image pairs.

[0066] It should be noted that the orthogonal polarization image pair includes a first polarization image and a second polarization image. The first polarization image and the second polarization image are a pair of polarization images acquired using a multi-layer target tomography device under fixed polarization illumination conditions. The orthogonal polarization image pair contains multiple target information, and the multiple target information contains preset coding layer information.

[0067] Specifically, the last layer of multiple targets to be imaged is set as the coding layer, and the information corresponding to the coding layer is the preset coding layer information.

[0068] It should be noted that, in this embodiment of the invention, the first polarization image and the second polarization image correspond to the images acquired by the second polarization modulation device along the horizontal and vertical directions.

[0069] In addition, in this embodiment of the invention, the last layer of the target to be imaged is set as the encoding layer. It can be understood that by setting the encoding layer, the light field information of the blank area of ​​the target to be imaged can be modulated. At the same time, the encoding layer can act as a high-resolution computational lens to achieve clear imaging of the target to be imaged.

[0070] The process of acquiring orthogonal polarization image pairs based on a multi-layer target tomography device is as follows:

[0071] Step 1: Turn on coherent light source 1;

[0072] Step 2: Align the coherent light source 1 with the center of the collimating lens 2 so that the light spot of the coherent light source 1 completely covers the target 4;

[0073] Step 3: Place the first polarization modulation device 3 in front of the target 4 and behind the collimating lens 2;

[0074] Step 4: Stack all targets 4 along the axis and place them in the same horizontal position, align them with the center of the collimating lens 2, and set the target spacing;

[0075] Step 5: Place detector 6 2-3 cm away from the last target, and place the second polarization modulation device 5 between target 4 and detector 6;

[0076] Step 6: Turn on detector 6 to receive the images generated by the first unit and the second unit, and adjust the first unit and the second unit so that the imaging spot is located at the center of the detector target surface;

[0077] Step 7: Rotate the first polarization modulator 3 to generate different polarization illuminations, and rotate the second polarization modulator 5 to make the polarization axis be in the 0-degree and 90-degree directions respectively to obtain two images containing orthogonal polarization information, which are used as the first polarization image and the second polarization image.

[0078] S102. Establish the current Jones matrix based on the current optical axis direction and the current phase delay, and establish the Jones vector for the corresponding initial polarized incident light using the orthogonal polarization image.

[0079] Optionally, the current Jones matrix is ​​represented as:

[0080]

[0081] Among them, Js t Let θ represent the current Jones matrix of the target at layer t, θ represent the current optical axis direction, δ represent the current phase delay, i represent the imaginary unit, and T represent the total number of layers of the target.

[0082] Jones vector representation is:

[0083]

[0084] Among them, E j Let E represent the Jones vector under the j-th illumination condition. x E represents the initial polarized incident light in the x-axis component of an orthogonal polarization image. y denoted as the initial polarized incident light in the y-axis component of the orthogonal polarization image, and J represents the total number of illumination conditions.

[0085] S103. Establish the current forward propagation model using the current Jones matrix and Jones vector.

[0086] Optionally, the current forward propagation model is represented as:

[0087]

[0088] in, This represents the current light field data of the target at layer T under the j-th illumination condition, PSF. free (d1) represents the free-space propagation kernel at a propagation distance d1, where d1 represents the distance between the first-layer target and the second-layer target, and PSF. free (d T-1 ) represents the propagation distance d T-1 The free-space propagation kernel under d T-1 This represents the distance between the target at layer T-1 and the target at layer T.

[0089] S104. Based on the orthogonal polarization image pair, perform parameter update processing on the current forward propagation model to obtain updated light field data.

[0090] Optionally, S104 may specifically include:

[0091] Based on the amplitude values ​​corresponding to the orthogonal polarization images and the current forward propagation model, the updated optical field data is calculated using the following formula:

[0092]

[0093] I represents the Jones vector component in the k-th row corresponding to the updated light field data of the target at layer T under the j-th illumination condition. jk This represents the Jones vector component in the k-th row corresponding to the light intensity value of the orthogonal polarization image under the j-th illumination condition. Let I represent the Jones vector component in the k-th row corresponding to the current light field data of the target at layer T under the j-th illumination condition, where I jk The intensity value is obtained based on the orthogonal polarization image.

[0094] It should be noted that, The overall representation represents the amplitude value corresponding to the orthogonal polarization image.

[0095] S105. The updated light field data is backpropagated to obtain the back-layer light field.

[0096] Alternatively, the back-layer light field can be represented as:

[0097]

[0098] in, Let $\frac{ ... This represents the Jones vector component in the k-th row corresponding to the updated light field data of the target at layer t under the j-th illumination condition, PSF. free (-d t ) represents the propagation distance -d t The free-space propagation kernel under d t This represents the distance between the target at layer t and the target at layer t+1.

[0099] Furthermore, in this embodiment of the invention, PSF free It can be represented as follows:

[0100]

[0101] Where d represents the interlayer spacing, n is the refractive index of the interlayer medium, and f x and f y Let λ and i represent the spatial frequency distribution along the x-axis and y-axis, respectively, where λ represents the wavelength and i represents the imaginary number.

[0102] S106. Based on the back-layer optical field, update the current optical axis direction and current phase delay in S102 to obtain the updated optical axis direction and updated phase delay. Use the updated optical axis direction as the current optical axis direction in S102 and the updated phase delay as the current phase delay in S102.

[0103] Optionally, S106 may specifically include:

[0104] Using the back-layer optical field, the current optical axis direction, and the current phase delay, the following formula is used for updating to obtain the non-complex increment of the current optical axis direction and the non-complex increment of the current phase delay:

[0105]

[0106] Let $\frac{ ... Indicates the state before the update Let represent the partial derivative expression of the element in the k-th row and u-th column of the current Jones matrix of the target at layer t with respect to θ. Let represent the partial derivative of the element in row k and column u of the current Jones matrix of the target at layer t with respect to δ, where Δθ represents the non-complex increment of the current optical axis direction, and Δδ represents the non-complex increment of the current phase delay. This represents the u-th Jones vector component of the current light field data of the target at layer t-1 under the j-th illumination condition;

[0107] Based on the non-complex increment of the current optical axis direction and the non-complex increment of the current phase delay, the updated optical axis direction and the updated phase delay are calculated using the following formula:

[0108] θ' = θ + α·Δθ;

[0109] δ' = δ + α·Δδ;

[0110] θ' represents the updated optical axis direction, δ' represents the updated phase delay, θ represents the current optical axis direction, δ represents the current phase delay, and α represents the step size coefficient;

[0111] The updated optical axis direction is used as the current optical axis direction in S102, and the updated phase delay is used as the current phase delay in S102.

[0112] Furthermore, in embodiments of the present invention, The update process is represented as follows:

[0113]

[0114] Indicates will In the updated result, γ represents the step size coefficient.

[0115] Will Substitute the calculation formula corresponding to S104 and repeat the update process of the target layer until an update has been completed under all polarized illuminations. Then, update the Js. t (t=1,2,...T) are fed into the forward propagation model as input, and then the update process is executed until the current Jones matrix corresponding to each layer of the target satisfies the preset convergence condition.

[0116] S107. Repeat S102-S106 until the current Jones matrix corresponding to each layer of the target in the orthogonal polarization image pair satisfies the preset convergence condition.

[0117] Optionally, the preset convergence condition is that the non-complex increment corresponding to the updated optical axis direction and the non-complex increment corresponding to the updated phase delay are both less than a preset threshold.

[0118] S108. When S107 is true, the updated optical axis direction and updated phase delay corresponding to the most recent execution of S106 are used as the result of multi-layer target tomography.

[0119] This invention provides a multi-layer target tomography method based on polarized illumination, comprising: using a pair of polarized images acquired under polarized illumination as the focus, effectively separating the target information of each single layer from the aliased image information of multiple targets; specifically, establishing a forward propagation model based on the polarization characteristics of the target scattered light field, and continuously updating the Jones matrix through an iterative process of backpropagation, ultimately achieving parallel reconstruction of multiple target information to obtain multi-layer target tomography results. Since this invention does not require calibration of hardware equipment and illumination conditions, it improves the efficiency of multi-layer target tomography.

[0120] To explain in detail the execution process of the method of the present invention, Figure 2 This is a flowchart illustrating a multi-layer target tomography method based on polarized illumination, provided as an embodiment of the present invention. Figure 2 As shown, firstly, a quarter-wave plate is rotated at fixed angles from 0 to 180 degrees to obtain polarized illumination, and two images are acquired under single polarized illumination to obtain an orthogonal polarized image pair. Then, the detector's planar optical field information is updated based on the orthogonal polarized image pair. During this period, the initial guess (initial optical axis direction and initial phase delay) for each target layer is set, and the optical field wavefront information is obtained according to the forward propagation model. Based on the planar optical field information and the optical field wavefront information, the optical field information behind the target layer is updated by backpropagation (obtaining the back-layer optical field). Then, the target information and the optical field information in front of the target layer are updated according to the formula in the above embodiment (obtaining the updated optical axis direction and updated phase delay). The updated optical axis direction is used as the initial optical axis direction, and the updated phase delay is used as the initial phase delay. The above process is repeated until the Jones matrix corresponding to each target layer in the orthogonal polarized image pair satisfies the preset convergence condition, and finally, the multi-layer target tomography result is obtained.

[0121] The method provided in this embodiment of the invention can be applied to electronic devices. Specifically, the electronic device can be a desktop computer, a portable computer, a smart mobile terminal, a server, etc., and this embodiment of the invention does not limit the application to such devices.

[0122] This corresponds to a multi-layer target tomography method based on polarized illumination. Figure 3 This is a schematic diagram of a multi-layer target tomography imaging device based on polarized illumination, provided as an embodiment of the present invention. Figure 3 As shown, the multi-layer target tomography device includes, in sequence: a first unit A, a second unit B, and a third unit C;

[0123] The first unit A includes: a coherent light source 1, a collimating lens 2, and a first polarization modulation device 3 arranged sequentially; the center of the coherent light source 1 is aligned with the center of the collimating lens 2.

[0124] The second unit B is equipped with a second polarization modulation device 5; multiple targets 4 to be imaged are stacked axially between the first unit A and the second polarization modulation device 5, and the centers of the multiple targets 4 to be imaged are all aligned with the center of the collimating lens 2; the last layer of the multiple targets to be imaged is set as an encoding layer.

[0125] The third unit C includes: a detector 6 and a computing device 7 arranged sequentially; the distance between the edge of the coding layer and the detector 6 is 1-5 mm.

[0126] Furthermore, in another embodiment, a polarization camera can be used to integrate the functions of the second polarization modulation device 5 and the detector 6 to reduce the design complexity of the multi-layer target tomography apparatus.

[0127] Based on the same inventive concept, embodiments of the present invention also provide a multi-layer target tomography imaging device based on polarized illumination. Figure 4 This is a schematic diagram of a multi-layer target tomography imaging device based on polarized illumination, provided as an embodiment of the present invention. Figure 4 As shown, it includes: an acquisition unit 401, a matrix building unit 402, an update unit 403, a processing unit 404, an iteration unit 405, and a judgment unit 406;

[0128] The acquisition unit 401 is used to: acquire orthogonal polarization image pairs; the first polarization image and the second polarization image in the orthogonal polarization image pair are a pair of polarization images acquired by a multi-layer target tomography imaging tomography device under fixed polarization light illumination conditions, the orthogonal polarization image pair contains multiple target information, and the multiple target information contains preset coding layer information;

[0129] Matrix establishment unit 402 is used to: establish the current Jones matrix based on the current optical axis direction and the current phase delay, and establish the Jones vector for the corresponding initial polarized incident light using an orthogonal polarization image;

[0130] The current forward propagation model is established by combining the current Jones matrix and Jones vector;

[0131] The update unit 403 is used to: perform parameter update processing on the current forward propagation model based on the orthogonal polarization image pair to obtain updated light field data;

[0132] Processing unit 404 is used to: perform backpropagation processing on the updated light field data to obtain the back-layer light field;

[0133] The update unit 403 is also used to: perform update processing based on the current optical axis direction and the current phase delay of the back-layer optical field to obtain the updated optical axis direction and the updated phase delay, and use the updated optical axis direction as the current optical axis direction in the matrix establishment unit, and use the updated phase delay as the current phase delay in the matrix establishment unit;

[0134] Iteration unit 405 is used to control the repeated execution of the matrix building unit, update unit and processing unit until the current Jones matrix corresponding to each layer of target in the orthogonal polarization image pair satisfies the preset convergence condition;

[0135] The judgment unit 406 is used to: when the preset convergence condition of the iteration unit is met, take the updated optical axis direction and updated phase delay of the most recent update in the update unit as the result of multi-layer target tomography.

[0136] Figure 5 A schematic diagram of a multi-layer target tomography device based on polarized illumination provided in an embodiment of the present invention includes: a processor 710, a storage medium 720, and a bus 730. The storage medium 720 stores machine-readable instructions executable by the processor 710. When the multi-layer target tomography device based on polarized illumination is running, the processor 710 communicates with the storage medium 720 via the bus 730, and the processor 710 executes the machine-readable instructions to perform the steps of the above-described method embodiment. Specific implementation methods and technical effects are similar and will not be described in detail here.

[0137] The storage medium may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the storage medium may also be at least one storage device located remotely from the aforementioned processor.

[0138] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0139] It should be noted that the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the invention.

[0140] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0141] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings and the disclosure, will understand and implement other variations of the disclosed embodiments in carrying out the claimed invention. In the description of the invention, the word "comprising" does not exclude other components or steps, "a" or "an" does not exclude a plurality, and "a plurality" means two or more, unless otherwise explicitly specified. Furthermore, while different embodiments may describe certain measures, this does not mean that these measures cannot be combined to produce good results.

[0142] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the inventive concept, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A multi-layer target tomography method based on polarized illumination, characterized in that, include: S101. Obtain an orthogonal polarization image pair; the first polarization image and the second polarization image in the orthogonal polarization image pair are a pair of polarization images acquired by a multi-layer target tomography device under fixed polarization illumination conditions, and the orthogonal polarization image pair contains multiple target information; the multiple target information contains preset coding layer information; S102. Establish the current Jones matrix based on the current optical axis direction and the current phase delay, and use the orthogonal polarization image to establish the Jones vector for the corresponding initial polarized incident light. S103. Establish the current forward propagation model using the current Jones matrix and the Jones vector; S104. Based on the orthogonal polarization image pair, perform parameter update processing on the current forward propagation model to obtain updated light field data; S105. Perform backpropagation processing on the updated light field data to obtain the back-layer light field; S106. Based on the back-layer optical field, update the current optical axis direction and the current phase delay in S102 to obtain the updated optical axis direction and the updated phase delay, and use the updated optical axis direction as the current optical axis direction in S102, and use the updated phase delay as the current phase delay in S102. S107. Repeat S102-S106 until the current Jones matrix corresponding to each layer of the target in the orthogonal polarization image pair satisfies the preset convergence condition. S108. When S107 is true, the updated optical axis direction and the updated phase delay corresponding to the most recent execution of S106 are used as the result of multi-layer target tomography.

2. The multi-layer target tomography method based on polarized illumination according to claim 1, characterized in that, The current Jones matrix is ​​represented as follows: Among them, Js t Let θ represent the current Jones matrix of the target at layer t, θ represent the current optical axis direction, δ represent the current phase delay, i represent the imaginary unit, and T represent the total number of layers of the target. The Jones vector is represented as: Among them, E j Let E represent the Jones vector under the j-th illumination condition. x E represents the initial polarized incident light in the x-axis component of an orthogonal polarization image. y denoted as the initial polarized incident light in the y-axis component of the orthogonal polarization image, and J represents the total number of illumination conditions.

3. The multi-layer target tomography method based on polarized illumination according to claim 2, characterized in that, The current forward propagation model is expressed as: in, This represents the current light field data of the target at layer T under the j-th illumination condition, PSF. free (d1) represents the free-space propagation kernel at a propagation distance d1, where d1 represents the distance between the first-layer target and the second-layer target, and PSF. free (d T-1 ) represents the propagation distance d T-1 The free-space propagation kernel under d T-1 d represents the distance between targets at layer T-1 and layer T. T This represents the distance between the target in layer T and the detector.

4. The multi-layer target tomography method based on polarized illumination according to claim 1, characterized in that, The step of updating the parameters of the current forward propagation model based on the orthogonal polarization image pair to obtain updated light field data includes: Based on the amplitude values ​​corresponding to the orthogonal polarization images and the current forward propagation model, the updated optical field data is calculated using the following formula: I represents the Jones vector component in the k-th row corresponding to the updated light field data of the target at layer T under the j-th illumination condition. jk This represents the Jones vector component in the k-th row corresponding to the light intensity value of the orthogonal polarization image under the j-th illumination condition. This represents the k-th row Jones vector component corresponding to the current light field data of the target at layer T under the j-th illumination condition, where I jk The intensity value is obtained based on the orthogonal polarization image.

5. The multi-layer target tomography method based on polarized illumination according to claim 1, characterized in that, The back-layer optical field is represented as follows: in, Let $\frac{ ... This represents the Jones vector component in the k-th row corresponding to the updated light field data of the target at layer t under the j-th illumination condition, PSF. free (-d t ) represents the propagation distance -d t The free-space propagation kernel under d t This represents the distance between the target at layer t and the target at layer t+1.

6. The multi-layer target tomography method based on polarized illumination according to claim 1, characterized in that, Based on the back-layer optical field, the current optical axis direction and the current phase delay in S102 are updated to obtain an updated optical axis direction and an updated phase delay. The updated optical axis direction is used as the current optical axis direction in S102, and the updated phase delay is used as the current phase delay in S102. This includes: Using the back-layer optical field, the current optical axis direction, and the current phase delay, the non-complex increments of the current optical axis direction and the current phase delay are obtained through the following formula: Let $\frac{ ... Indicates the state before the update Let represent the partial derivative expression of the element in the k-th row and u-th column of the current Jones matrix of the target at layer t with respect to θ. Let represent the partial derivative of the element in row k and column u of the current Jones matrix of the target at layer t with respect to δ, where Δθ represents the non-complex increment of the current optical axis direction, and Δδ represents the non-complex increment of the current phase delay. This represents the u-th Jones vector component of the current light field data of the target at layer t-1 under the j-th illumination condition; Based on the non-complex increment of the current optical axis direction and the non-complex increment of the current phase delay, the updated optical axis direction and the updated phase delay are calculated using the following formulas: θ' = θ + α·Δθ; δ' = δ + α·Δδ; θ' represents the updated optical axis direction, δ' represents the updated phase delay, θ represents the current optical axis direction, δ represents the current phase delay, and α represents the step size coefficient; The updated optical axis direction is taken as the current optical axis direction in S102, and the updated phase delay is taken as the current phase delay in S102.

7. The multi-layer target tomography method based on polarized illumination according to claim 1, characterized in that, The preset convergence condition is that the non-complex increment corresponding to the updated optical axis direction and the non-complex increment corresponding to the updated phase delay are both less than a preset threshold.

8. A multi-layer target tomography imaging device based on polarized illumination, characterized in that, include: The system includes an acquisition unit, a matrix creation unit, an update unit, a processing unit, an iteration unit, and a judgment unit. The acquisition unit is used to: acquire orthogonal polarization image pairs; the first polarization image and the second polarization image in the orthogonal polarization image pair are a pair of polarization images acquired by a multi-layer target tomography device under fixed polarization illumination conditions, and the orthogonal polarization image pair contains multiple target information; the multiple target information contains preset coding layer information; The matrix establishment unit is used to: establish the current Jones matrix based on the current optical axis direction and the current phase delay, and establish the Jones vector for the corresponding initial polarized incident light using the orthogonal polarization image; The current forward propagation model is established by combining the current Jones matrix and the Jones vector. The updating unit is used to: perform parameter update processing on the current forward propagation model based on the orthogonal polarization image pair to obtain updated light field data; The processing unit is used to: perform backpropagation processing on the updated light field data to obtain the post-layer light field; The updating unit is further configured to: perform an update process based on the current optical axis direction and the current phase delay of the back-layer optical field to obtain an updated optical axis direction and an updated phase delay, and use the updated optical axis direction as the current optical axis direction in the matrix building unit, and use the updated phase delay as the current phase delay in the matrix building unit; The iterative unit is used to control the repeated execution of the matrix establishment unit, the update unit, and the processing unit until the current Jones matrix corresponding to each layer of the target in the orthogonal polarization image pair satisfies the preset convergence condition. The judgment unit is used to: when the preset convergence condition of the iteration unit is met, take the updated optical axis direction and the updated phase delay of the most recent update in the update unit as the result of multi-layer target tomography.

9. A multi-layer target tomography imaging device based on polarized illumination, characterized in that, The multi-layer target tomography device based on polarized illumination includes, in sequence, a first unit, a second unit, and a third unit; The first unit includes: a coherent light source, a collimating lens, and a first polarization modulation device arranged sequentially; the center of the coherent light source is aligned with the center of the collimating lens; The second unit is provided with a second polarization modulation device; a plurality of targets to be imaged are stacked along the axial direction between the first unit and the second polarization modulation device, and the centers of the plurality of targets to be imaged are all aligned with the center of the collimating lens; the last layer of the plurality of targets to be imaged is set as an encoding layer; The third unit includes: a detector and a computing device arranged sequentially; the distance between the edge of the coding layer and the detector is 1-5 mm.

10. A multi-layer target tomography imaging device based on polarized illumination, characterized in that, include: The device includes a processor, a storage medium, and a bus. The storage medium stores machine-readable instructions executable by the processor. When the polarized illumination-based multi-layer target tomography apparatus is in operation, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the polarized illumination-based multi-layer target tomography method as described in any one of claims 1-7.

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