Rapid high-throughput non-interference phase imaging method and system based on polarization multiplexing

Abstract

The invention discloses a rapid high-throughput non-interference phase imaging method and system based on polarization multiplexing. The method comprises the following steps: recording in-focus and out-of-focus light intensity distribution information; obtaining phase distribution information of the tested sample at a certain illumination angle by using a light intensity transmission equation; constructing complex amplitude by using the obtained phase distribution information and light intensity distribution information, implementing Fourier transform to a frequency domain, and filtering complex amplitude distribution in the frequency domain by using a frequency domain filtering means; superposing the complex amplitude distribution of each sub-aperture after filtering to obtain high-flux complex amplitude distribution; inverse Fourier transform is carried out on the high-flux complex amplitude distribution, and the complex amplitude is transformed into an airspace; and extracting argument information of the complex amplitude distribution, and obtaining a high-throughput phase distribution image by using a phase unwrapping algorithm. The contradiction between high-throughput imaging and rapid imaging is effectively considered, the accuracy is improved by using the high-throughput imaging method without sacrificing the imaging speed, and the method has wide application prospects.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-interference quantitative phase imaging in computational optical imaging, and in particular relates to a fast high-throughput non-interference phase imaging method and system based on polarization multiplexing. Background Art

[0002] Due to the high-frequency nature of light waves, common photodetectors usually cannot meet the sampling frequency required to fully record the light field, and can only collect the amplitude information of the light field. However, in common optical measurement scenarios, the phase often carries important information such as the surface morphology or internal structure of the object being measured. Quantitative phase imaging technology implements a phase recovery algorithm through the collected intensity image to invert the phase of the light field, and then can obtain the surface morphology or internal structure information of the object being measured that cannot be obtained by traditional imaging methods through the phase information.

[0003] Quantitative phase imaging methods can be broadly divided into two categories: interference and non-interference. Interference methods have the advantage of high measurement accuracy, but are also restricted by unfavorable factors such as coherent noise, complex system, and large environmental disturbances. Compared with interference methods, non-interference methods have the advantages of being applicable to partially coherent illumination, simple system, and good environmental robustness. They can be divided into two categories: direct solution and iterative solution. Direct solution methods can quickly obtain the phase information of the object under test, but it is often difficult to achieve high-throughput imaging at the same time; iterative solution methods have the advantage of high throughput but are often difficult to achieve fast measurement. Generally speaking, high-throughput phase imaging often means that the system resolution can be improved without sacrificing the field of view, which effectively alleviates the contradiction between high imaging resolution and low imaging field of view in traditional imaging. However, how to strike a balance between fast measurement and high throughput is still a difficult problem to be solved. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a fast high-throughput non-interference phase imaging method and system based on polarization multiplexing in view of the deficiencies in the above-mentioned prior art, which is used to solve the technical problem that the current common phase imaging methods cannot take into account both measurement speed and high-throughput imaging at the same time.

[0005] The present invention adopts the following technical solutions: A fast high-throughput non-interference phase imaging method based on polarization multiplexing comprises the following steps: Record in-focus and out-of-focus light intensity distribution information; The phase distribution information of the sample under test at a certain illumination angle is obtained using the light intensity transmission equation; The obtained phase distribution information and light intensity distribution information are used to construct a complex amplitude, and Fourier transform is performed to the frequency domain, and the complex amplitude distribution is filtered in the frequency domain by using frequency domain filtering means; The complex amplitude distribution of each sub-aperture after filtering is superimposed to obtain a high-throughput complex amplitude distribution; The high-throughput complex amplitude distribution is subjected to inverse Fourier transform to transform the complex amplitude into the spatial domain; the argument information of the complex amplitude distribution is extracted, and the phase unwrapping algorithm is applied to obtain the high-throughput phase distribution image.

[0006] Preferably, two polarization cameras which are in the in-focus and out-focus states respectively are used to simultaneously record the in-focus and out-focus light intensity distribution information.

[0007] Preferably, obtaining the phase distribution information of the sample under test at a certain illumination angle is specifically as follows: The axial differential of the light intensity in the direction of the optical axis is estimated by using the finite difference method; Phase retrieval using the light intensity transmission equation; Using the auxiliary equation, the light intensity transmission equation is transformed into the Poisson equation, combined with the known axial differential of the light intensity , using fast Fourier transform to obtain the phase distribution without phase unwrapping.

[0008] Preferably, the axial differential of the light intensity is estimated as follows:

[0009] in, is the defocus distance, is the out-of-focus light intensity distribution, is the in-focus light intensity distribution.

[0010] Preferably, a fast Fourier transform is used to obtain a phase distribution without phase unwrapping as follows:

[0011] in, is the Fourier transform, is the inverse Fourier transform, is the wavelength, is the phase, is a first-order differential operator, is the frequency coordinate , is the focal plane light intensity distribution, is the axial partial differential of the light intensity.

[0012] Preferably, the complex amplitude is constructed, and Fourier transform is performed to the frequency domain, and the complex amplitude distribution is filtered in the frequency domain by using frequency domain filtering means: The complex amplitude distribution is obtained by using the phase distribution and the collected focal plane intensity distribution ; Complex amplitude distribution Apply Fourier transform to transform the complex amplitude into the frequency domain; The complex amplitude distribution is filtered in the frequency domain using frequency domain filtering.

[0013] Preferably, filtering each illumination sub-aperture is specifically performed as follows:

[0014] in, is the frequency domain coordinate form of the spatial domain complex amplitude distribution, is the light intensity distribution for each illumination subaperture, is the phase distribution of each subaperture, is an imaginary unit, For mask.

[0015] Preferably, the high-throughput complex amplitude distribution is specifically:

[0016] in, is a high-throughput complex amplitude distribution, is the number of illumination subapertures. is the Fourier transform, For the The focal plane light intensity of each sub-aperture is For the The phase of each sub-aperture, is an imaginary unit, For the A mask with a sub-aperture.

[0017] Preferably, the high-throughput spatial domain complex amplitude distribution is specifically:

[0018] in, is the spatial complex amplitude distribution, is the number of illumination subapertures. is the inverse Fourier transform, For the The focal plane light intensity of each sub-aperture is For the The phase of each sub-aperture, is an imaginary unit, For the A mask with a sub-aperture.

[0019] In a second aspect, an embodiment of the present invention provides a fast high-throughput non-interference phase imaging system based on polarization multiplexing, comprising: An information module, recording in-focus and out-of-focus light intensity distribution information; Phase module, which uses the light intensity transmission equation to obtain the phase distribution information of the sample under test at a certain illumination angle; The filtering module constructs a complex amplitude using the obtained phase distribution information and the light intensity distribution information, and performs Fourier transform to the frequency domain, and filters the complex amplitude distribution using frequency domain filtering in the frequency domain; A superposition module superimposes the complex amplitude distribution of each sub-aperture after filtering to obtain a high-throughput complex amplitude distribution; The output module performs inverse Fourier transform on the high-throughput complex amplitude distribution and transforms the complex amplitude into the spatial domain; extracts the argument information of the complex amplitude distribution and applies the phase unwrapping algorithm to obtain the high-throughput phase distribution image.

[0020] In a third aspect, a computer device comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned fast high-throughput non-interference phase imaging method based on polarization multiplexing when executing the computer program.

[0021] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, including a computer program, which, when executed by a processor, implements the steps of the above-mentioned fast high-throughput non-interference phase imaging method based on polarization multiplexing.

[0022] In a fifth aspect, a chip comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned fast high-throughput non-interference phase imaging method based on polarization multiplexing when executing the computer program.

[0023] In a sixth aspect, an embodiment of the present invention provides an electronic device, including a computer program, which, when executed by the electronic device, implements the steps of the above-mentioned fast high-throughput non-interference phase imaging method based on polarization multiplexing.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects: A fast, high-throughput non-interference phase imaging method based on polarization multiplexing uses field of view multiplexing, frequency domain synthetic aperture, and phase recovery technology. It uses the method of polarization camera focal plane multiplexing to simultaneously collect the light intensity distribution of the sample under two different illumination angles without losing the field of view, thereby improving the measurement speed of the imaging system in the amplitude distribution acquisition stage. At the same time, the light intensity transmission equation is used to directly solve the phase, achieving fast phase solution, and improving the measurement speed of the imaging system in the phase recovery stage. The implementation of multi-angle illumination uses the Fourier frequency shift theorem to move the high-frequency components that were originally unable to enter the imaging system into the system passband, and high-throughput imaging is achieved through the synthetic aperture method. The light intensity transmission equation phase recovery method used is a direct solution non-interference phase recovery method, which has the advantages of being applicable to partially coherent illumination, simple system, and good environmental robustness.

[0025] Furthermore, compared with the traditional method of estimating the axial differential of light intensity The commonly used method of utilizing mechanical displacement of the object plane or the image plane and using two polarization cameras that are in focus and out of focus respectively to simultaneously collect a total of four in-focus and out-focus images of two different polarization channels has the advantage of being able to effectively reduce the mechanical movement error of the traditional method, thereby improving the accuracy of the axial differential estimation of the light intensity and thus improving the phase imaging accuracy; on the other hand, simultaneously collecting two polarization channels can also effectively improve the measurement acquisition speed to meet the requirements of fast measurement.

[0026] Furthermore, compared with the traditional method of using a light source parallel to the optical axis to illuminate the sample to be tested for imaging, the use of inclined multi-angle illumination can move the high-frequency information components greater than the system cutoff frequency in the traditional method into the passband of the optical system, which can further expand the system cutoff frequency range and achieve the purpose of high-throughput imaging.

[0027] Furthermore, due to the conjugate characteristics of the system transfer function under oblique illumination conditions, in addition to obtaining high-frequency information, redundant high-frequency information is also obtained during oblique illumination imaging. Therefore, it is necessary to adopt certain filtering methods to filter out the redundant information. Compared with spatial domain filtering, frequency domain filtering has the advantages of small amount of calculation and easy operation. Therefore, it is necessary to use the focal plane intensity information and phase information to construct the complex amplitude and transform it to the frequency domain. In the frequency domain, the complex amplitude distribution is filtered using frequency domain filtering methods.

[0028] Furthermore, since the parameters of the frequency domain filter mask are only related to the wavelength of the illumination source, the numerical aperture of the objective lens and the numerical aperture of the illumination source, after the system parameters are determined, the mask parameters can be directly determined and the mask filter can be applied to achieve the purpose of fast calculation in the image post-processing stage.

[0029] Furthermore, each sub-aperture after filtering carries the low-frequency information of the center of the measured sample and the high-frequency information in a certain coordinate direction. In order to improve the overall phase resolution of the measured sample, it is necessary to superimpose the complex amplitudes of each sub-aperture after filtering in the frequency domain and fill the spectrum so that the imaging flux can be effectively expanded, thereby achieving the purpose of improving the overall phase resolution rather than improving the resolution in a single direction.

[0030] Furthermore, since the above operations are a series of frequency domain operations on the complex amplitude distribution, and what we are really concerned about is the spatial phase distribution of the sample under test, it is necessary to transform the complex amplitude back to the spatial domain and extract the phase distribution of the complex amplitude distribution. Since the trigonometric inverse tangent function is used in the process of extracting the phase distribution, this operation will cause the original absolute phase distribution to be wrapped in Therefore, it is necessary to adopt an appropriate unwrapping algorithm to recalculate the wrapped phase into the absolute phase distribution, so as to finally obtain the high-throughput phase distribution information of the measured sample.

[0031] It can be understood that the beneficial effects of the second to sixth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0032] In summary, the present invention effectively takes into account the contradiction between high-throughput imaging and fast imaging, and uses high-throughput imaging methods to achieve accuracy improvement without sacrificing imaging speed. It has the advantages of high acquisition speed and high reconstruction speed. Compared with the existing phase recovery method based on direct solution, it has the advantages of high throughput and high precision.

[0033] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a flow chart of the method of the present invention; Figure 2 It is a schematic diagram of the system of the present invention; Figure 3 A schematic diagram of the arrangement method of the illumination light source and the selection of the corresponding polarization state in the present invention; Figure 4 A schematic diagram of system flux in an implementation example of a traditional phase imaging method; Figure 5 A schematic diagram of system flux in a specific embodiment of the present invention; Figure 6 A schematic diagram of a computer device provided by an embodiment of the present invention; Figure 7 The block diagram of a chip provided according to an embodiment of the present invention.

[0035] Among them: 1. Fiber-coupled LED light source; 2. Collimating lens; 3. Adjustable aperture; 4. Sample to be tested and sample fixture; 5. Infinity-corrected objective lens; 6. Tube lens; 7. Plane reflector; 8. Beam splitter prism; 9. Polarization camera placed in focus; 10. Polarization camera placed out of focus. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0038] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0039] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects are in an "or" relationship.

[0040] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0041] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0042] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0043] The present invention provides a fast high-throughput non-interference phase imaging method based on polarization multiplexing. Aiming at the problem that the current common phase imaging method cannot take into account both the measurement speed and the high-throughput imaging at the same time, a plurality of asymmetric light sources with different illumination angles are applied on the basis of the traditional optical axis symmetrical illumination, so that the high-frequency information that could not be collected by the optical system before is moved into the passband of the optical system, thereby realizing the improvement of the imaging system flux; the light intensity information under a plurality of illumination angles is simultaneously collected by means of polarization focal plane multiplexing, thereby meeting the technical requirement of fast collection; the light intensity transmission equation is used to perform fast phase solution on the in-focus and out-of-focus light intensity diagram, thereby meeting the technical requirement of fast measurement; the polarization focal plane field of view multiplexing is used to improve the collection speed; the synthetic aperture method is used to realize high-throughput imaging, thereby effectively alleviating the contradiction between high throughput and measurement speed, and having important application value in fast high-throughput phase imaging.

[0044] See also Figure 1 The present invention provides a fast high-throughput non-interference phase imaging method based on polarization multiplexing, including five parts: light intensity map acquisition, quantitative phase imaging, frequency domain filtering, synthetic aperture, and spatial domain unwrapping. The specific steps are as follows: S1. Using two polarization cameras in the in-focus and out-focus states respectively to simultaneously record the in-focus and out-focus light intensity distribution information; For polarization cameras, two channels with orthogonal polarization states can generally achieve focal plane isolation, thereby simultaneously collecting light intensity distribution information of two different polarization channels.

[0045] S2. Use the light intensity transmission equation to obtain the phase distribution information of the sample under test at a certain illumination angle ; S201, using a finite difference method to estimate the axial differential of the light intensity in the direction of the optical axis, and using a formula to estimate the axial differential of the light intensity; The axial differential of the light intensity is estimated as follows:

[0046] in, is the defocus distance, is the out-of-focus light intensity distribution, is the in-focus light intensity distribution.

[0047] S202, performing phase recovery using a light intensity transmission equation; The expression of the light intensity transmission equation is:

[0048] in, is the wavelength, is the phase, is a first-order differential operator; The light intensity transmission equation is a second-order elliptic partial differential equation and cannot be solved directly. Without loss of generality, the following approximation is usually adopted for solution.

[0049] S203, using the auxiliary equation, transform the light intensity transmission equation into Poisson's equation, combined with the known axial differential of light intensity , using fast Fourier transform to obtain the phase distribution without phase unwrapping.

[0050] The auxiliary equation is specifically:

[0051] The light intensity transmission equation is usually transformed into Poisson's equation, as follows:

[0052]

[0053] Combined with the known axial differential of the light intensity The phase distribution without phase unwrapping is directly obtained using fast Fourier transform, as follows:

[0054] in, is the Fourier transform, is the inverse Fourier transform.

[0055] S3, constructing a complex amplitude using the phase distribution information obtained in step S2 and the focal plane light intensity distribution information obtained in step S1, and performing Fourier transform to the frequency domain, and filtering the complex amplitude distribution in the frequency domain using frequency domain filtering means; S301, using the phase distribution and the collected focal plane light intensity distribution to obtain the complex amplitude distribution ; Complex Amplitude Distribution The details are as follows:

[0056] in, is the light intensity distribution for each illumination subaperture, is the phase distribution of each subaperture, Is an imaginary unit.

[0057] S302, complex amplitude distribution Apply Fourier transform to transform the complex amplitude into the frequency domain;

[0058] in, It is the frequency domain coordinate form of the complex amplitude distribution in the spatial domain.

[0059] S303 , filtering the complex amplitude distribution in the frequency domain by using a frequency domain filtering method.

[0060] Select the appropriate mask , so that the low-frequency components of the central illumination aperture are retained as a whole, while only the high-frequency components that do not overlap with the central low-frequency components are retained in the four illumination apertures of the top, bottom, left and right, and the frequency components that overlap with the central mask part are removed, and each illumination sub-aperture is filtered.

[0061] The filtering for each illumination sub-aperture is as follows:

[0062] S4, superimposing the complex amplitude distribution of each sub-aperture after filtering in step S3 to obtain a high-throughput complex amplitude distribution; The high-throughput complex amplitude distribution is specifically:

[0063] in, is the frequency domain coordinate, is the number of subapertures.

[0064] S5, performing an inverse Fourier transform on the high-throughput complex amplitude distribution in step S4, transforming the complex amplitude into the spatial domain; extracting the argument information of the complex amplitude distribution, and applying a phase unwrapping algorithm to finally obtain a high-throughput phase distribution image.

[0065] The high-throughput spatial domain complex amplitude distribution is specifically:

[0066] in, for, is the phase distribution of each subaperture, Is an imaginary unit.

[0067] The argument information of the complex amplitude distribution is extracted, and the phase unwrapping algorithm is applied to finally obtain a high-throughput phase distribution image. Since the operation of extracting the argument from the complex amplitude distribution uses the inverse tangent function, it will cause the phase to be wrapped in In the process, although the phase distribution obtained in step S1 does not need to be unwrapped, it is still necessary to apply an appropriate unwrapping algorithm to perform phase unwrapping. The phase distribution after phase unwrapping is the high-throughput phase map.

[0068] See also Figure 2 In another embodiment of the present invention, a fast high-throughput non-interference phase imaging device based on polarization multiplexing is provided, and the device can be used to implement the fast high-throughput non-interference phase imaging method based on polarization multiplexing. Specifically, the fast high-throughput non-interference phase imaging device based on polarization multiplexing includes: Polarized multi-angle lighting system: comprising an LED light source, a multimode optical fiber, an optical fiber flange, an optical fiber flange fixture, a collimating lens 2, and an adjustable aperture 3.

[0069] The LED light source, multimode optical fiber, and optical fiber flange together constitute the optical fiber-coupled LED light source 1. In order to facilitate the integration of the lighting system, an optical fiber flange with an SM05 external thread specification is selected for integration with the light source fixture.

[0070] In order to achieve the maximum cutoff frequency of the system under bright field conditions , usually the numerical aperture of the fiber-coupled LED light source 1 needs to be The numerical aperture of the objective lens Match.

[0071] Generally, the relative position relationship between multi-angle illumination and central optical axis illumination is roughly calculated using the ray tracing method in geometric optics. However, since the light source in a real optical system cannot be regarded as an ideal point light source and has a certain size, it is necessary to subtract the size of the light source itself from the result of the theoretical calculation and use this size as the basis for designing the fiber optic flange fixture.

[0072] In order to achieve a better light intensity image signal-to-noise ratio and better imaging quality, it is necessary to collimate the divergent LED light source into parallel light. The most important principle to consider when selecting the collimating lens 2 is the numerical aperture of the collimating lens. Usually needs to be larger than the numerical aperture of the objective .

[0073] Usually, in order to achieve a larger numerical aperture, an aspheric lens, a best shape lens or a double cemented achromatic lens with a small focal length and a large clear aperture is selected.

[0074] After collimating the parallel light, since the aperture of the collimating lens 2 is usually larger than that of the microscope objective, it is necessary to add a variable aperture after the collimating lens to control the spot diameter of the outgoing parallel light beam to reduce the adverse effect of the diffracted light that does not pass through the imaging system on the final imaging quality.

[0075] Imaging system: includes the sample to be tested and the sample fixture 4, the infinity correction objective lens 5, the tube lens 6, and the plane reflector 7.

[0076] The sample to be tested and the sample fixture 4 are used to provide stable clamping of the sample and serve as a reference for the object surface. In order to facilitate adjustment, the sample to be tested and the sample fixture 4 have three degrees of freedom of displacement in the xyz direction.

[0077] Since the phase imaging system based on the light intensity transmission equation usually needs to collect in-focus and out-of-focus images, it is particularly important to ensure that the system magnification remains unchanged when out of focus, and to control the influence of parallax. Therefore, it is particularly critical to construct a double telecentric system on the object side and image side through the infinity correction objective lens 5 and the tube lens 6. The advantage of the double telecentric system is that the aperture stop is located on the rear focal plane of the infinity correction objective lens 5 and the front focal plane of the tube lens 6. All light rays incident from the object side parallel to the optical axis remain parallel to the optical axis when emitted from the image side, making the double telecentric optical path have the characteristics of small parallax and stable magnification.

[0078] In order to achieve the best magnification and aberration correction, the focal length of the tube lens 6 needs to match the focal length of the infinity correction objective lens 5. At the same time, in order to reduce the influence of aberration and chromatic aberration, the tube lens 6 should adopt a double cemented achromatic lens.

[0079] In order to achieve real-time measurement of dynamic samples such as cells in suspension, the above-mentioned polarized multi-angle illumination system and the rest of the imaging system should be installed vertically. The function of the plane reflector 7 is to deflect the light and deflect the vertical light path to the horizontal direction, so as to facilitate the construction of the subsequent image acquisition system.

[0080] Image acquisition system: includes a beam splitter prism 8, a polarization camera 9 placed in focus, and a polarization camera 10 placed out of focus.

[0081] For the collection of in-focus and out-of-focus light intensity distribution, in order to reduce the influence of mechanical movement on the measurement speed and measurement accuracy, the light path is divided into two beams by using a beam splitter prism 8, one beam is sent to the in-focus polarization camera 9, and the other beam is sent to the out-of-focus polarization camera 10, forming a dual-camera collection system with a common light path. Since the image-side outgoing light field has a polarization state, a depolarizing beam splitter prism (NPBS) should be used for splitting, so as to achieve the purpose of not changing the polarization state of the light field.

[0082] For a dual-camera system with a common optical path, the dual-camera field of view matching matrix should be calibrated in advance using standard materials such as resolution plates to keep the image coordinate systems in the two camera fields of view consistent.

[0083] In step S1, it is mentioned that the generation of the polarization state of the illumination light source follows the principle of orthogonal polarization states, and the selection of the polarization acquisition channel of the polarization camera is consistent with that in step S1.

[0084] Host computer control system: It consists of an embedded single-board computer with GPIO, corresponding control software and its interface, and image processing algorithm.

[0085] The main functions of the control software include the control of the light source timing and the control of the camera's external trigger signal.

[0086] In order to achieve fast acquisition, GPIO is used to control the timing of each LED light source controller. Figure 3 For example, the specific timing can be divided into: 1. Light up the center LED and send out the 0° channel of PCMOS to collect external trigger signal; 2. Turn off the center LED and light up the left and upper LEDs and send out the 0° and 90° channels of PCMOS to collect external trigger signals; 3. Turn off the left and upper LEDs and light up the right and lower LEDs and send out the 0° and 90° channels of PCMOS to collect external trigger signals.

[0087] The above three steps constitute a cycle, each of which is continuously cycled and can achieve fast dynamic measurement.

[0088] Image processing algorithms mainly include light intensity transmission equation solution algorithm, two-dimensional image Fourier transform and inverse transform algorithm, frequency domain synthetic aperture algorithm, phase unwrapping algorithm, etc. In actual integration, multi-threading technology should be used to enable multiple calculation steps to be performed simultaneously to improve the reconstruction speed.

[0089] In another embodiment of the present invention, a fast high-throughput non-interference phase imaging system based on polarization multiplexing is provided. The system can be used to implement the above-mentioned fast high-throughput non-interference phase imaging method based on polarization multiplexing. Specifically, the fast high-throughput non-interference phase imaging system based on polarization multiplexing includes an information module, a phase module, a filtering module, a superposition module and an output module.

[0090] Among them, the information module records the in-focus and out-of-focus light intensity distribution information; Phase module, which uses the light intensity transmission equation to obtain the phase distribution information of the sample under test at a certain illumination angle; The filtering module constructs a complex amplitude using the obtained phase distribution information and the light intensity distribution information, and performs Fourier transform to the frequency domain, and filters the complex amplitude distribution using frequency domain filtering in the frequency domain; A superposition module superimposes the complex amplitude distribution of each sub-aperture after filtering to obtain a high-throughput complex amplitude distribution; The output module performs inverse Fourier transform on the high-throughput complex amplitude distribution and transforms the complex amplitude into the spatial domain; extracts the argument information of the complex amplitude distribution and applies the phase unwrapping algorithm to obtain the high-throughput phase distribution image.

[0091] In another embodiment of the present invention, a terminal device is provided, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of a fast high-throughput non-interference phase imaging method based on polarization multiplexing, including: Record the in-focus and out-of-focus light intensity distribution information; use the light intensity transmission equation to obtain the phase distribution information of the sample under test at a certain illumination angle; use the obtained phase distribution information and light intensity distribution information to construct the complex amplitude, and perform Fourier transform to the frequency domain, and use frequency domain filtering in the frequency domain to filter the complex amplitude distribution; superimpose the complex amplitude distribution of each sub-aperture after filtering to obtain a high-throughput complex amplitude distribution; perform an inverse Fourier transform on the high-throughput complex amplitude distribution and transform the complex amplitude to the spatial domain; extract the angular information of the complex amplitude distribution, and apply the phase unwrapping algorithm to obtain a high-throughput phase distribution image.

[0092] See also Figure 6 , the terminal device is a computer device, and the computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, the method for calculating the fluid composition in the reservoir transformation wellbore in the embodiment is implemented. To avoid repetition, it is not described one by one here. Alternatively, when the computer program 63 is executed by the processor 61, the functions of each model / unit in the fast high-throughput non-interference phase imaging system based on polarization multiplexing in the embodiment are implemented. To avoid repetition, it is not described one by one here.

[0093] The computer device 60 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will appreciate that Figure 6 This is only an example of the computer device 60 and does not constitute a limitation of the computer device 60. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0094] The processor 61 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0095] The memory 62 may be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the computer device 60.

[0096] Furthermore, the memory 62 may include both an internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is to be output.

[0097] See also Figure 7 , the terminal device is a chip, and the chip 600 of this embodiment includes a processor 622, which may be one or more, and a memory 632 for storing a computer program executable by the processor 622. The computer program stored in the memory 632 may include one or more modules, each corresponding to a set of instructions. In addition, the processor 622 may be configured to execute the computer program to perform the above-mentioned fast high-throughput non-interference phase imaging method based on polarization multiplexing.

[0098] In addition, the chip 600 may further include a power supply component 626 and a communication component 650, wherein the power supply component 626 may be configured to perform power management of the chip 600, and the communication component 650 may be configured to implement communication, for example, wired or wireless communication, of the chip 600. In addition, the chip 600 may further include an input / output interface 658. The chip 600 may operate based on an operating system stored in the memory 632.

[0099] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium, which is a memory device in a terminal device for storing programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs. It should be noted that the computer-readable storage medium here can be a high-speed RAM memory, or a non-volatile memory (Non-VolatileMemory), such as at least one disk memory.

[0100] One or more instructions stored in a computer-readable storage medium may be loaded and executed by a processor to implement the corresponding steps of the method for rapid high-throughput non-interference phase imaging based on polarization multiplexing in the above-mentioned embodiment; one or more instructions in the computer-readable storage medium are loaded and executed by the processor as follows: Record the in-focus and out-of-focus light intensity distribution information; use the light intensity transmission equation to obtain the phase distribution information of the sample under test at a certain illumination angle; use the obtained phase distribution information and light intensity distribution information to construct the complex amplitude, and perform Fourier transform to the frequency domain, and use frequency domain filtering in the frequency domain to filter the complex amplitude distribution; superimpose the complex amplitude distribution of each sub-aperture after filtering to obtain a high-throughput complex amplitude distribution; perform an inverse Fourier transform on the high-throughput complex amplitude distribution and transform the complex amplitude to the spatial domain; extract the angular information of the complex amplitude distribution, and apply the phase unwrapping algorithm to obtain a high-throughput phase distribution image.

[0101] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can usually be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0102] See also Figure 4 , shows the flux of the system when only a light source parallel to the optical axis and symmetrical to the center of the optical axis is used for illumination in a real experimental example. As can be seen from the figure, only the spatial frequency is less than The frequency information passes through the optical system, and due to the low-pass filtering effect of the optical system, it is higher than the cut-off frequency. The frequency cannot pass through the optical system, and finally presents Figure 4 effect.

[0103] See also Figure 5 , showing the high-throughput imaging results obtained using the method proposed in this patent in a real experimental example. Figure 4 The cut-off frequency is The method of this patent successfully extends the cutoff frequency of the system to , compared to Figure 4The theoretical resolution of the traditional method represented by this patent has doubled, and high-throughput imaging has been successfully achieved, which can obtain more specific details of the sample being tested. By combining the relevant high-precision rapid imaging methods proposed in this patent in implementation, higher imaging flux and imaging accuracy can be obtained without sacrificing imaging time, and rapid high-throughput non-interference quantitative phase imaging can be achieved.

[0104] In summary, the present invention provides a fast high-throughput non-interference phase imaging method and system based on polarization multiplexing, which uses the light intensity transmission equation for phase recovery, uses the polarization camera focal plane multiplexing to realize the simultaneous acquisition of light intensity distribution under multiple different illumination angles, and uses the synthetic aperture method to realize high-throughput imaging, which effectively alleviates the shortcomings of the current iterative phase recovery method that realizes high-throughput imaging but has a long measurement time, and the direct phase recovery method that has a short measurement time but cannot realize high-throughput imaging, and has important application value in quantitative phase imaging.

[0105] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0106] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0107] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0108] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0109] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0110] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0111] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0112] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices, and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0113] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0114] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0115] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A fast high-throughput non-interference phase imaging method based on polarization multiplexing, characterized in that: The following steps are involved: Record in-focus and out-of-focus light intensity distribution information; The phase distribution information of the sample under test at a certain illumination angle is obtained using the light intensity transmission equation; The obtained phase distribution information and light intensity distribution information are used to construct a complex amplitude, and Fourier transform is performed to the frequency domain, and the complex amplitude distribution is filtered in the frequency domain by using frequency domain filtering means; The complex amplitude distribution of each sub-aperture after filtering is superimposed to obtain a high-throughput complex amplitude distribution; The high-throughput complex amplitude distribution is subjected to inverse Fourier transform to transform the complex amplitude into the spatial domain; the argument information of the complex amplitude distribution is extracted, and the phase unwrapping algorithm is applied to obtain the high-throughput phase distribution image.

2. The fast high-throughput non-interference phase imaging method based on polarization multiplexing according to claim 1, characterized in that: Two polarization cameras in the in-focus and out-focus states are used to simultaneously record the in-focus and out-focus light intensity distribution information.

3. The fast high-throughput non-interference phase imaging method based on polarization multiplexing according to claim 1, characterized in that: The phase distribution information of the sample under test at a certain illumination angle is obtained as follows: The axial differential of the light intensity in the direction of the optical axis is estimated by using the finite difference method; Phase retrieval using the light intensity transmission equation; Using the auxiliary equation, the light intensity transmission equation is transformed into the Poisson equation, combined with the known axial differential of the light intensity , using fast Fourier transform to obtain the phase distribution without phase unwrapping.

4. The fast high-throughput non-interference phase imaging method based on polarization multiplexing according to claim 3, characterized in that: The axial differential of the light intensity is estimated as follows: in, is the defocus distance, is the out-of-focus light intensity distribution, is the in-focus light intensity distribution.

5. The fast high-throughput non-interference phase imaging method based on polarization multiplexing according to claim 3, characterized in that: Obtaining phase distribution without phase unwrapping using fast Fourier transform as follows: in, is the Fourier transform, is the inverse Fourier transform, is the wavelength, is the phase, is a first-order differential operator, is the frequency coordinate , is the focal plane light intensity distribution, is the axial partial differential of the light intensity.

6. The fast high-throughput non-interference phase imaging method based on polarization multiplexing according to claim 1, characterized in that: Construct the complex amplitude and perform Fourier transform to the frequency domain. Use frequency domain filtering in the frequency domain to filter the complex amplitude distribution. Specifically: The complex amplitude distribution is obtained by using the phase distribution and the collected focal plane intensity distribution ; Complex amplitude distribution Apply Fourier transform to transform the complex amplitude into the frequency domain; The complex amplitude distribution is filtered in the frequency domain using frequency domain filtering.

7. The fast high-throughput non-interference phase imaging method based on polarization multiplexing according to claim 6, characterized in that: The filtering for each illumination sub-aperture is as follows: in, is the frequency domain coordinate form of the spatial domain complex amplitude distribution, is the light intensity distribution for each illumination subaperture, is the phase distribution of each subaperture, is an imaginary unit, For mask.

8. The fast high-throughput non-interference phase imaging method based on polarization multiplexing according to claim 1, characterized in that: The high-throughput complex amplitude distribution is specifically: in, is a high-throughput complex amplitude distribution, is the number of illumination subapertures; is the Fourier transform, For the The focal plane light intensity of each sub-aperture is For the The phase of each sub-aperture, is an imaginary unit, For the A mask with a sub-aperture.

9. The fast high-throughput non-interference phase imaging method based on polarization multiplexing according to claim 1, characterized in that: The high-throughput spatial domain complex amplitude distribution is specifically: in, is the spatial complex amplitude distribution, is the number of illumination subapertures; is the inverse Fourier transform, For the The focal plane light intensity of each sub-aperture is For the The phase of each sub-aperture, is an imaginary unit, For the A mask with a sub-aperture.

10. A fast high-throughput non-interference phase imaging system based on polarization multiplexing, characterized in that: include: An information module, recording in-focus and out-of-focus light intensity distribution information; Phase module, which uses the light intensity transmission equation to obtain the phase distribution information of the sample under test at a certain illumination angle; The filtering module constructs a complex amplitude using the obtained phase distribution information and the light intensity distribution information, and performs Fourier transform to the frequency domain, and filters the complex amplitude distribution using frequency domain filtering in the frequency domain; A superposition module superimposes the complex amplitude distribution of each sub-aperture after filtering to obtain a high-throughput complex amplitude distribution; The output module performs inverse Fourier transform on the high-throughput complex amplitude distribution and transforms the complex amplitude into the spatial domain; extracts the argument information of the complex amplitude distribution and applies the phase unwrapping algorithm to obtain the high-throughput phase distribution image.

Images