Single-frame phase shift off-axis digital holographic phase determination method and device

Abstract

The invention relates to the technical field of holographic imaging, and discloses a single-frame phase shift off-axis digital holographic phase determination method and device, and the method comprises the steps: carrying out the preprocessing of an original off-axis hologram, and generating an off-axis hologram; processing the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shift amounts; respectively carrying out image processing on the off-axis hologram, the first off-axis hologram and the second off-axis hologram to obtain an original complex amplitude result, a first complex amplitude result and a second complex amplitude result containing real image information; according to the original complex amplitude result, the first complex amplitude result and the second complex amplitude result, simulating to generate a reference light diagram only containing carrier information; and multiplying the reference light pattern only containing carrier information by the original off-axis hologram, and filtering high-frequency carrier information through a filtering algorithm to obtain phase information of the to-be-detected sample. Through a digital phase shift technology and a filtering technology, high-quality reconstruction of an off-axis digital holographic technology can be realized only through a single-frame off-axis hologram.

Description

Technical Field

[0001] The present invention relates to the technical field of holographic imaging, and in particular to a method and device for determining the phase of a single-frame phase-shifted off-axis digital hologram. Background Art

[0002] According to whether there is an angle between the object light and the reference light, digital holography technology is divided into on-axis digital holography technology and off-axis digital holography technology. On-axis digital holography can make full use of the spatial bandwidth utilization of the image sensor and has a higher resolution, but the real image spectrum, zero-order spectrum and conjugate image spectrum overlap with each other, and multiple phase-shifted holograms need to be collected to achieve three-dimensional reconstruction, which increases the complexity of the system. Off-axis digital holography introduces an angle between the object light and the reference light to achieve spectral separation of the real image spectrum, zero-order spectrum and conjugate image spectrum, and can obtain wavefront in a single exposure, thereby improving the time or space efficiency of the system and being suitable for high-precision measurement of dynamic samples.

[0003] One of the existing technologies proposes an off-axis digital imaging method based on multiple derivatives. This method reconstructs the phase information of the sample under test through the third-order derivative relationship. However, in order to eliminate distortion information such as aberration, an additional sample-free hologram needs to be collected, and the distortion information of the sample-free hologram must be consistent with the distortion information of the hologram containing sample information. Therefore, this method places high demands on the acquisition device and has low universality.

[0004] Another existing technology proposes a method for improving the resolution of a single-frame off-axis hologram based on extrapolation iteration and Kronecker interpolation. This method combines iterative technology with interpolation technology to achieve high-quality reconstruction of off-axis digital holography. However, its algorithm is highly complex and requires more time cost to obtain high-quality imaging.

[0005] It can be seen from this that the existing phase determination method for phase-shifted off-axis digital holography has high requirements on the stability of the acquisition system, strict requirements on the accuracy of the optical path alignment, and high computational complexity. At the same time, due to the limited dynamic range of the acquisition system, phase information loss or distortion is prone to occur when the height of the object changes greatly, making it difficult to maintain stability in a dynamic environment for the demand for multi-frame images. Summary of the invention

[0006] The purpose of the present invention is to provide a single-frame phase-shifted off-axis digital holographic phase determination method, device, computer-readable storage medium and electronic device, which can solve at least one of the above-mentioned technical problems. The specific solution is as follows: According to the specific embodiments disclosed in the present invention, the first aspect of the present invention provides a single-frame phase-shifted off-axis digital holographic phase determination method, which pre-processes the original off-axis hologram containing the information of the sample to be tested to generate an off-axis hologram; Processing the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shifts; Performing two-dimensional Fourier transform, bandpass filtering and two-dimensional inverse Fourier transform on the off-axis hologram, the first off-axis hologram and the second off-axis hologram respectively to obtain an original complex amplitude result containing real image information, a first complex amplitude result and a second complex amplitude result; Simulating and generating a reference light pattern containing only carrier information according to the original complex amplitude result containing real image information, the first complex amplitude result and the second complex amplitude result; The reference light image containing only carrier information is multiplied by the original off-axis hologram, and the phase information of the sample to be tested is obtained after filtering out the high-frequency carrier information through a filtering algorithm.

[0007] Preferably, the preprocessing of the original off-axis hologram containing the information of the sample to be tested to generate the off-axis hologram comprises: The original off-axis hologram containing the information of the sample to be tested is obtained by the off-axis digital holography device I 0 , the expression is: ; in, a is the DC term; b is the modulation term of the interference fringes; is the phase; k x For the original off-axis hologram x The carrier frequency of the direction; k y For the original off-axis hologram y The carrier frequency of the direction; The off-axis hologram is generated by removing the zero-order diffraction image information contained in the original off-axis hologram , the expression is: .

[0008] Preferably, the processing of the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shifts comprises: Using digital phase shift technology to move the off-axis hologram by m pixels in a first direction to obtain a first off-axis hologram; The off-axis hologram is moved n pixels in a second direction by using a digital phase shifting technique to obtain a second off-axis hologram.

[0009] Preferably, the off-axis hologram is processed to obtain a first off-axis hologram and a second off-axis hologram with different phase shifts, comprising: The off-axis hologram is shifted to the left by 1 pixel using digital phase shift technology to obtain the first off-axis hologram: ; The off-axis hologram is moved upward by 1 pixel using digital phase shifting technology to obtain a second off-axis hologram: .

[0010] Preferably, simulating and generating reference light containing only carrier information according to the original complex amplitude result containing real image information, the first complex amplitude result and the second complex amplitude result comprises: The first complex amplitude result is divided by the original complex amplitude result to obtain the off-axis hologram edge x The carrier frequency in the direction is expressed as: ; The second complex amplitude result is divided by the original complex amplitude result to obtain the off-axis hologram along the y The carrier frequency in the direction is expressed as: ; in, C is the original complex amplitude result containing real image information; is the first complex amplitude result containing real image information; is the second complex amplitude result containing real image information; represents the imaginary part, Represents the real part.

[0011] The off-axis hologram is x direction of the carrier frequency and the off-axis hologram along y The carrier frequency in the direction is simulated to generate a reference light pattern containing only carrier information.

[0012] Preferably, the multiplication of the reference light image containing only carrier information with the original off-axis hologram, and obtaining the phase information of the sample to be tested after filtering out the high-frequency carrier information through a filtering algorithm, comprises: The reference light image containing only carrier information is multiplied by the original off-axis hologram, and a mean filter is used to perform smoothing interpolation to obtain the phase information of the sample to be tested.

[0013] Preferably, the reference light containing only carrier information is multiplied by the original off-axis hologram, and the phase information of the sample to be tested is obtained after filtering out the high-frequency carrier information through a filtering algorithm, including: The reference light image containing only carrier information is multiplied by the original off-axis hologram, and a bicubic interpolation filter is used to perform smooth interpolation to obtain the phase information of the sample to be measured.

[0014] According to a specific embodiment disclosed in the present invention, a second aspect of the present invention discloses a single-frame phase-shifted off-axis digital holographic phase determination device, comprising: An image preprocessing unit, used for preprocessing the original off-axis hologram containing the information of the sample to be tested to generate an off-axis hologram; An image processing unit, used for processing the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shift amounts; An image conversion unit is used to perform two-dimensional Fourier transformation, bandpass filtering and two-dimensional Fourier inverse transformation on the off-axis hologram, the first off-axis hologram and the second off-axis hologram respectively to obtain an original complex amplitude result containing real image information, a first complex amplitude result and a second complex amplitude result; An image production unit, used for simulating and generating a reference light image containing only carrier information according to the original complex amplitude result containing real image information, the first complex amplitude result and the second complex amplitude result; The image filtering unit is used to multiply the reference light image containing only carrier information with the original off-axis hologram, and obtain the phase information of the sample to be tested after filtering out the high-frequency carrier information through a filtering algorithm.

[0015] According to the specific embodiments disclosed in the present invention, the third aspect of the present invention discloses a computer-readable storage medium having a computer program stored thereon, wherein when the program is executed by a processor, the method for editing the content in a document as described in any one of the above items is implemented.

[0016] According to the specific embodiments disclosed in the present invention, the fourth aspect of the present invention discloses an electronic device, comprising: one or more processors; a storage device for storing one or more programs, when the one or more programs are executed by the one or more processors, the one or more processors implement the method for editing the content in a document as described in any one of the above items.

[0017] Compared with the prior art, the above solution disclosed in the present invention has at least the following beneficial effects: The present invention uses digital phase shifting technology to obtain multiple off-axis holograms with different phase shift amounts, without the need for a high-precision phase shifter, and can achieve high-precision measurement of dynamic samples; by filtering the multiplied hologram, the information of the measured sample can be obtained without phase compensation. Therefore, the algorithm complexity of the present invention is low, time and space costs are saved, and high-quality reconstruction of off-axis digital holography technology can be achieved with only a single frame image. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the disclosure of the present invention, and together with the specification, are used to explain the principles disclosed in the present invention. Obviously, the drawings described below are only some embodiments disclosed in the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings: Figure 1 A flow chart of a single-frame phase-shifted off-axis digital holographic phase determination method provided by the first embodiment of the present invention; Figure 2 a is an off-axis hologram obtained in the first embodiment of the present invention; Figure 2 b is the first off-axis hologram after being phase-shifted upward by one pixel; Figure 2 c is the second off-axis hologram after being shifted one pixel to the left; Figure 2 d is the original complex amplitude result diagram including the real image; Figure 2 e is the first complex amplitude result diagram containing the real image; Figure 2 f is the second complex amplitude result graph containing the real image; Figure 2 g is the result of multiplying the original off-axis hologram and the simulated reference light pattern; Figure 2 h is the information diagram of the tested sample after the phase information is restored; Figure 2 i is the original sample information; Figure 3 A schematic diagram of a single-frame phase-shifted off-axis digital holographic phase determination device provided by a second embodiment of the present invention; Figure 4 A schematic structural diagram of an electronic device provided in the third embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages disclosed in the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments disclosed in the present invention, rather than all the embodiments. Based on the embodiments disclosed in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection disclosed in the present invention.

[0020] The terms used in the embodiments disclosed in the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the disclosure of the present invention. The singular forms "a", "said" and "the" used in the embodiments disclosed in the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0021] It should be understood that although the terms first, second, third, etc. may be used to describe in the disclosed embodiments of the present invention, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, without departing from the scope of the disclosed embodiments of the present invention, the first may also be referred to as the second, and similarly, the second may also be referred to as the first.

[0022] The following is combined with Figure 1-Figure 2 Detailed description of the alternative embodiments of the present disclosure.

[0023] Digital phase shifting technology refers to phase shifting an off-axis hologram at intervals of one or several pixels along one direction to obtain multiple off-axis holograms containing different phase shift components. The phase information of the object containing the carrier is calculated using a recovery algorithm, and then the carrier is removed to obtain accurate object phase information.

[0024] Bandpass filtering technology retains part of the image information (real image) while filtering out unnecessary information (conjugate image) by selecting frequencies within a certain range in the frequency domain.

[0025] The first embodiment of the present invention provides a single-frame phase-shifted off-axis digital holographic phase determination method, such as Figure 1 As shown, the following steps are included: Step S1, preprocessing the original off-axis hologram containing the information of the sample to be tested to generate an off-axis hologram; Step S2, processing the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shifts; Step S3, performing two-dimensional Fourier transform, bandpass filtering and two-dimensional inverse Fourier transform on the off-axis hologram, the first off-axis hologram and the second off-axis hologram respectively to obtain an original complex amplitude result containing real image information, a first complex amplitude result and a second complex amplitude result; Step S4, simulating and generating a reference light pattern containing only carrier information according to the original complex amplitude result containing real image information, the first complex amplitude result and the second complex amplitude result; Step S5, multiplying the reference light image containing only carrier information with the original off-axis hologram, and filtering out the carrier information through a filtering algorithm to obtain the phase information of the sample to be tested.

[0026] The present invention utilizes digital phase shift technology and filtering technology, does not require phase compensation, and only requires a single-frame off-axis hologram to achieve high-quality reconstruction of off-axis digital holography.

[0027] Furthermore, the step of preprocessing the original off-axis hologram containing the information of the sample to be tested in step S1 to generate the off-axis hologram includes: Step S1-1: Obtaining an original off-axis hologram containing information of the sample to be tested through an off-axis digital holographic device I 0 .

[0028] Step S1-2: removing the original off-axis hologram I 0 The zero-order diffraction image information contained in the off-axis hologram is generated I .

[0029] Specifically, the off-axis digital holographic device used to obtain the original off-axis hologram can be an interference pattern of the sample to be measured obtained by a CCD camera in any prior art device, and there is no restriction on the system stability and optical path alignment accuracy of the device.

[0030] When a plane reference light wave has a certain angle with the object light wave of the sample to be measured in the transmission direction, interference will occur. At this time, the original off-axis hologram obtained I 0 It can be expressed as: ; in, a is the DC term; b is the modulation term of the interference fringes; is the phase; k x The original off-axis hologram x The carrier frequency of the direction; k y The original off-axis hologram y The carrier frequency of the direction; Since the original off-axis hologram I 0 In order to better separate the +1-order diffraction real image, the off-axis hologram is obtained by obtaining the mean information of the off-axis hologram and performing subtraction to remove the zero-order image contained in the original off-axis hologram. I , which can be expressed as: .

[0031] Step S2: Off-axis hologram IProcessing is performed to obtain a first off-axis hologram and a second off-axis hologram with different phase shift amounts, comprising the following steps: Step S2-1: using digital phase shifting technology to move the off-axis hologram in a first direction m pixels, and obtain a first off-axis hologram; Step S2-2: using digital phase shifting technology to move the off-axis hologram to a second direction n pixels to obtain a second off-axis hologram.

[0032] In this step, multiple off-axis holograms with different phase shifts can be obtained simply by using digital phase shifting technology, without the need for a high-precision phase shifter, thereby achieving high-precision measurement of dynamic samples.

[0033] In a preferred embodiment of the present invention, in order to ensure the fidelity of the phase information, The off-axis hologram is moved to the left by 1 pixel to obtain the first off-axis hologram: ; The off-axis hologram is moved upward by 1 pixel to obtain a second off-axis hologram: .

[0034] In step S3, the off-axis hologram is subjected to a two-dimensional Fourier transform, a bandpass filter and a two-dimensional Fourier inverse transform to obtain an original complex amplitude result containing real image information. C , the expression is: ; The first off-axis hologram is subjected to two-dimensional Fourier transform, bandpass filtering and two-dimensional inverse Fourier transform to obtain the first complex amplitude containing real image information: , the expression is: ; The second off-axis hologram is subjected to two-dimensional Fourier transform, bandpass filtering and two-dimensional inverse Fourier transform to obtain the second complex amplitude result containing real image information. , the expression is; ; In this step, the phase information in the time domain is converted into frequency domain information by performing two-dimensional Fourier transform, bandpass filtering and two-dimensional inverse Fourier transform operations, so as to extract the real image information using a bandpass filter. Among them, the time domain phase information of the off-axis hologram is converted into frequency domain phase information by performing a two-dimensional Fourier transform.

[0035] By using a bandpass filter, the conjugate image in the off-axis hologram is filtered out, thereby extracting specific real image information from multiple effective information.

[0036] The extracted real image information is converted from the frequency domain to the time domain by performing a two-dimensional inverse Fourier transform.

[0037] Step S4, simulating and generating a reference light pattern containing only carrier information according to the original complex amplitude result containing real image information, the first complex amplitude result and the second complex amplitude result, comprising the following steps: Step S4-1, compare the first complex amplitude result with the original complex amplitude result C Divide to get the carrier frequency in the x direction in, represents the imaginary part, Represents the real part.

[0038] Step S4-2, dividing the second complex amplitude result by the original complex amplitude result to obtain the carrier frequency in the y direction in, represents the imaginary part, Represents the real part.

[0039] Step S4-3, simulating the carrier frequency in the x direction and the carrier frequency in the y direction to generate a reference light pattern containing only carrier information, the expression is: ; In this step, the complex amplitude result is divided by the original complex amplitude result to obtain x and y The carrier information in the direction is removed, and the phase information and original carrier modulation information are eliminated.

[0040] In step S5, the reference light image containing only carrier information is multiplied by the original off-axis hologram, and the expression is as follows: , In the off-axis hologram, the carrier frequency is much greater than the object phase frequency. The second term in the above formula is the term containing carrier modulation and is considered to be in the high-frequency region. The first term is the term that only contains the phase information of the sample being measured.

[0041] The high-frequency phase information is further filtered out through a filtering algorithm to obtain the phase information of the sample to be tested.

[0042] Specifically, the phase information of the sample under test can be obtained by performing smooth interpolation using a mean filter or a bicubic interpolation filter.

[0043] Mean filtering is a commonly used image processing technology. Its basic principle is to replace each pixel value in an image with the average value of its neighborhood pixels. It is mainly used to remove image noise and achieve image smoothing.

[0044] Bicubic interpolation filtering uses the information of surrounding known pixels to estimate the grayscale value or signal value of the interpolation point. By applying the cubic spline interpolation function in the vertical and horizontal directions, a smooth interpolation effect is achieved to avoid obvious jagged or distorted images.

[0045] Example 1 In this embodiment, Matlab software is used to simulate the process of off-axis hologram phase determination, and the initial parameters of the simulated image are set: the sampling frequency is 4.8µm, the amplitude transmittance of the background part is 0.2, the phase is 0rad, the amplitude transmittance of the line and digital part is 1, and the phase is -2rad; the reference light wavelength is 632.8nm.

[0046] According to the off-axis hologram expression; , Get as Figure 2 Off-axis hologram shown in a.

[0047] The off-axis hologram is moved one pixel to the left to obtain the first off-axis hologram. The generated image is as follows: Figure 2 As shown in b; The off-axis hologram is moved up by one pixel to obtain a second off-axis hologram. The generated image is as follows: Figure 2 As shown in c; right I , I 1 and I 2 Perform Fourier transform, bandpass filtering and inverse Fourier transform respectively to obtain the original complex amplitude result C containing real image information: ; First complex amplitude result : ; Second complex amplitude result : ; Respectively Figure 2 d. Figure 2 e and Figure 2 f: Divide the above complex amplitude results to obtain the carrier frequencies in the x and y directions respectively: ; ; Using the above obtained x and y The carrier frequency in the direction of the reference light is simulated to generate a reference light containing only the carrier information and multiplied with the original hologram to obtain an off-axis hologram containing only the phase in the low-frequency region, such as Figure 2 As shown in g.

[0048] The phase information of the sample under test can be obtained by smoothing with a mean filter or a bicubic interpolation filter, such as Figure 2 h.

[0049] and Figure 2 i By comparison, it can be seen that the single-frame phase-shifted off-axis digital holographic phase determination method of the present invention is effective, the reconstructed image has a high degree of restoration, and high-quality reconstruction is achieved.

[0050] The second aspect of the present invention discloses an apparatus embodiment that is consistent with the above embodiment, which is used to implement the method steps described in the above embodiment. The explanation based on the same name meaning is the same as the above embodiment, and has the same technical effect as the above embodiment, which will not be repeated here.

[0051] The second aspect of the present invention provides a single-frame phase-shifted off-axis digital holographic phase determination device, such as Figure 3 As shown, including: An image preprocessing unit 201 is used to preprocess the original off-axis hologram containing the information of the sample to be tested to generate an off-axis hologram; An image processing unit 202 is used to process the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shift amounts; An image transformation unit 203 is used to perform two-dimensional Fourier transformation, bandpass filtering and two-dimensional Fourier inverse transformation on the off-axis hologram, the first off-axis hologram and the second off-axis hologram respectively to obtain an original complex amplitude result containing real image information, a first complex amplitude result and a second complex amplitude result; An image production unit 204 is used to simulate and generate a reference light image containing only carrier information according to the original complex amplitude result containing real image information, the first complex amplitude result and the second complex amplitude result; The image filtering unit 205 is used to multiply the reference light image containing only carrier information with the original off-axis hologram, and obtain the phase information of the sample to be tested after filtering out the high-frequency carrier information through a filtering algorithm.

[0052] A third aspect of the present invention provides an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method steps described in the above embodiments.

[0053] A fourth aspect of the present invention provides a computer-readable storage medium, wherein the computer storage medium stores computer-executable instructions, and the computer-executable instructions can execute the method steps described in the above embodiments.

[0054] Reference below Figure 4 , which shows a schematic diagram of the structure of an electronic device suitable for implementing the disclosed embodiment of the present invention. The terminal device in the disclosed embodiment of the present invention may include but is not limited to mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (personal digital assistants), PADs (tablet computers), PMPs (portable multimedia players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 4 The electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments disclosed in the present invention.

[0055] like Figure 4 As shown, the electronic device may include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 401, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 402 or a program loaded from a storage device 408 to a random access memory (RAM) 403. In RAM 403, various programs and data required for the operation of the electronic device are also stored. The processing device 401, ROM 402, and RAM 403 are connected to each other via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0056] Typically, the following devices may be connected to the I / O interface 405: an input device 406 including, for example, a touch screen, a touch pad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; an output device 407 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 408 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 409. The communication device 409 may allow the electronic device to communicate with other devices wirelessly or by wire to exchange data. Although Figure 4 An electronic device having various devices is shown, but it should be understood that it is not required to implement or possess all the devices shown. More or fewer devices may be implemented or possessed instead.

[0057] In particular, according to the embodiments disclosed in the present invention, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present invention include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program contains program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication device 409, or installed from the storage device 408, or installed from the ROM 402. When the computer program is executed by the processing device 401, the above-mentioned functions defined in the method of the embodiment disclosed in the present invention are executed.

[0058] It should be noted that the computer-readable medium disclosed in the present invention may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, device or device. In the present invention, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. Computer readable signal media may also be any computer readable medium other than computer readable storage media, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. The program code contained on the computer readable medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0059] The computer-readable medium may be included in the electronic device, or may exist independently without being incorporated into the electronic device.

[0060] Computer program code for performing the operations disclosed in the present invention may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0061] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to the various embodiments disclosed in the present invention. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some implementations as replacements, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0062] The units involved in the embodiments disclosed in the present invention may be implemented by software or hardware, wherein the name of a unit does not limit the unit itself in some cases.

Claims

1. A single-frame phase-shifted off-axis digital holographic phase determination method, characterized in that: include: Preprocessing the original off-axis hologram containing the information of the sample to be tested to generate an off-axis hologram; Processing the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shifts; Performing two-dimensional Fourier transform, bandpass filtering and two-dimensional inverse Fourier transform on the off-axis hologram, the first off-axis hologram and the second off-axis hologram respectively to obtain an original complex amplitude result containing real image information, a first complex amplitude result and a second complex amplitude result; Simulating and generating a reference light pattern containing only carrier information according to the original complex amplitude result containing real image information, the first complex amplitude result and the second complex amplitude result; The reference light image containing only carrier information is multiplied by the original off-axis hologram, and the phase information of the sample to be tested is obtained after filtering out the high-frequency carrier information through a filtering algorithm.

2. The method according to claim 1, characterized in that The preprocessing of the original off-axis hologram containing the information of the sample to be tested to generate the off-axis hologram comprises: The original off-axis hologram containing the information of the sample to be tested is obtained by the off-axis digital holography device , the expression is: ； in, a is the DC term; is the phase; b is the modulation term of the interference fringes; k x For the original off-axis hologram x The carrier frequency of the direction; k y For the original off-axis hologram y The carrier frequency of the direction; The off-axis hologram is generated by removing the zero-order diffraction image information contained in the original off-axis hologram, and the expression is: 。 3. The method according to claim 1, characterized in that The processing of the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shifts comprises: The off-axis hologram is moved in a first direction using a digital phase shifting technique. m pixels, and obtain a first off-axis hologram; The off-axis hologram is moved to a second direction using digital phase shifting technology n pixels to obtain a second off-axis hologram.

4. The method according to claim 3, characterized in that The processing of the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shifts comprises: The off-axis hologram is shifted to the left by 1 pixel using digital phase shift technology to obtain the first off-axis hologram, which is expressed as: ； The off-axis hologram is moved upward by 1 pixel using digital phase shift technology to obtain a second off-axis hologram, which is expressed as: 。 5. The method according to claim 1, characterized in that The simulating and generating a reference light pattern containing only carrier information according to the original complex amplitude result containing real image information, the first complex amplitude result and the second complex amplitude result comprises: The first complex amplitude result is divided by the original complex amplitude result to obtain the off-axis hologram edge x The carrier frequency in the direction is expressed as: ; The second complex amplitude result is divided by the original complex amplitude result to obtain the off-axis hologram along the y The carrier frequency in the direction is expressed as: ; in, C is the original complex amplitude result containing real image information; is the first complex amplitude result containing real image information; is the second complex amplitude result containing real image information; represents the imaginary part, represents the real part, The off-axis hologram is x direction of the carrier frequency and the off-axis hologram along y The carrier frequency in the direction is simulated to generate a reference light pattern containing only carrier information.

6. The method according to claim 1, characterized in that The method of multiplying the reference light image containing only carrier information with the original off-axis hologram and filtering out the high-frequency carrier information by a filtering algorithm to obtain the phase information of the sample to be tested comprises: The reference light image containing only carrier information is multiplied by the original off-axis hologram, and a mean filter is used to perform smoothing interpolation to obtain the phase information of the sample to be tested.

7. The method according to claim 1, characterized in that The method of multiplying the reference light image containing only carrier information with the original off-axis hologram and filtering out the high-frequency carrier information by a filtering algorithm to obtain the phase information of the sample to be tested comprises: The reference light image containing only carrier information is multiplied by the original off-axis hologram, and a bicubic interpolation filter is used to perform smooth interpolation to obtain the phase information of the sample to be measured.

8. A single-frame phase-shifted off-axis digital holographic phase determination device, characterized in that: include: An image preprocessing unit, used for preprocessing the original off-axis hologram containing the information of the sample to be tested to generate an off-axis hologram; An image processing unit, used for processing the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shift amounts; An image conversion unit is used to perform two-dimensional Fourier transformation, bandpass filtering and two-dimensional Fourier inverse transformation on the off-axis hologram, the first off-axis hologram and the second off-axis hologram respectively to obtain an original complex amplitude result containing real image information, a first complex amplitude result and a second complex amplitude result; An image production unit, used for simulating and generating a reference light image containing only carrier information according to the original complex amplitude result containing real image information, the first complex amplitude result and the second complex amplitude result; The image filtering unit is used to multiply the reference light image containing only carrier information with the original off-axis hologram, and obtain the phase information of the sample to be tested after filtering out the high-frequency carrier information through a filtering algorithm.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

10. An electronic device, characterized in that: include: one or more processors; A storage device for storing one or more programs, which, when executed by the one or more processors, enables the one or more processors to implement the method according to any one of claims 1 to 7.

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