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

Abstract

The present invention relates to the field of holographic imaging technology. The present invention discloses a method and device for determining the phase of a single-frame phase-shifted off-axis digital hologram, including: preprocessing the original off-axis hologram 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 shift amounts; respectively performing 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 containing real image information, a first complex amplitude result, and a second complex amplitude result; simulating and generating a reference light map containing only carrier information according to the original complex amplitude result, the first complex amplitude result, and the second complex amplitude result; multiplying the reference light map containing only carrier information by the original off-axis hologram, and filtering out the high-frequency carrier information through a filtering algorithm to obtain the phase information of the sample to be measured. Through digital phase shift technology and filtering technology, high-quality reconstruction of off-axis digital holographic technology can be achieved with only a single-frame off-axis hologram.

Description

Technical Field

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

[0002] According to whether there is an angle between the object light and the reference light, digital holographic technology is divided into in-line digital holographic technology and off-axis digital holographic technology. In-line digital holography can make full use of the spatial bandwidth utilization rate of the image sensor and has a high resolution. However, the real image spectrum, the zero-order spectrum, and the conjugate image spectrum overlap with each other, and multiple phase-shifted holograms need to be acquired 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, realizing the spectral separation of the real image spectrum, the zero-order spectrum, and the conjugate image spectrum, and can obtain the wavefront in a single exposure, improving the time or space efficiency of the system and being suitable for high-precision measurement of dynamic samples.

[0003] One of the prior arts proposes an off-axis digital imaging method based on multi-derivatives. This method reconstructs the phase information of the measured sample through a third-order derivative relationship. However, in order to eliminate aberration and other distortion information, an additional hologram without a sample needs to be acquired, and it is required that the distortion information of the hologram without a sample is consistent with the distortion information of the hologram containing the sample information. Therefore, this method places high requirements on the acquisition device and has low universality.

[0004] Another of the prior arts proposes a method for improving the resolution of a single-frame off-axis hologram based on extrapolation iteration and Kronecker interpolation. This method combines the iterative technique and the interpolation technique to achieve high-quality reconstruction of off-axis digital holographic technology. However, its algorithm complexity is high, and more time costs need to be sacrificed to obtain high-quality imaging.

[0005] It can be seen from this that the existing phase-shifting off-axis digital holographic phase determination methods have high requirements for the stability of the acquisition system, strict requirements for the accuracy of the optical path alignment, and large computational complexity. At the same time, due to the limited dynamic range of the acquisition system, phase information loss or distortion is likely to occur when the object height changes greatly, resulting in difficulty in maintaining the stability of the requirement for multiple frames of images in a dynamic environment. Summary of the Invention

[0006] The object of the present invention is to provide a method, device, computer-readable storage medium, and electronic device for determining the phase of a single-frame phase-shifting off-axis digital hologram, which can solve at least one of the above-mentioned technical problems. The specific solutions are as follows:

[0007] According to the specific embodiments disclosed in the present invention, in the first aspect of the present invention, a method for determining the phase of a single-frame phase-shifted off-axis digital hologram is provided. The original off-axis hologram containing the information of the sample to be measured is preprocessed to generate an off-axis hologram;

[0008] The off-axis hologram is processed to obtain a first off-axis hologram and a second off-axis hologram with different phase shift amounts;

[0009] The off-axis hologram, the first off-axis hologram, and the second off-axis hologram are respectively subjected to two-dimensional Fourier transform, band-pass filtering, and two-dimensional inverse Fourier transform to obtain the original complex amplitude result containing real image information, the first complex amplitude result, and the second complex amplitude result;

[0010] A reference light map containing only carrier information is simulated and generated according to the original complex amplitude result containing real image information, the first complex amplitude result, and the second complex amplitude result;

[0011] The reference light map containing only carrier information is multiplied by the original off-axis hologram, and after filtering out the high-frequency carrier information through a filtering algorithm, the phase information of the sample to be measured is obtained.

[0012] Preferably, the preprocessing of the original off-axis hologram containing the information of the sample to be measured to generate an off-axis hologram includes:

[0013] The original off-axis hologram containing the information of the sample to be measured is obtained through an off-axis digital holographic device I 0 , and the expression is:

[0014] ;

[0015] wherein, a is the DC term;

[0016] b is the modulation term of the interference fringes; is the phase;

[0017] k x is the carrier frequency of the original off-axis hologram along the x direction;

[0018] k y is the carrier frequency of the original off-axis hologram along the y direction;

[0019] The zero-order diffraction image information contained in the original off-axis hologram is removed to generate an off-axis hologram , and the expression is:

[0020] .

[0021] Preferably, processing the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shift amounts includes:

[0022] Using digital phase shift technology to move the off-axis hologram m pixels in a first direction to obtain a first off-axis hologram;

[0023] Using digital phase shift technology to move the off-axis hologram n pixels in a second direction to obtain a second off-axis hologram.

[0024] Preferably, processing the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shift amounts includes:

[0025] Using digital phase shift technology to move the off-axis hologram 1 pixel to the left to obtain a first off-axis hologram:

[0026] ;

[0027] Using digital phase shift technology to move the off-axis hologram 1 pixel upward to obtain a second off-axis hologram:

[0028] .

[0029] Preferably, simulating and generating a 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 includes:

[0030] Dividing the first complex amplitude result by the original complex amplitude result to obtain the carrier frequency of the off-axis hologram along x the direction, and the expression is: ;

[0031] Dividing the second complex amplitude result by the original complex amplitude result to obtain the carrier frequency of the off-axis hologram along y the direction, and the expression is: ;

[0032] Wherein, C is the original complex amplitude result containing real image information;

[0033] is the first complex amplitude result containing real image information;

[0034] is the second complex amplitude result containing real image information;

[0035] represents the imaginary part, represents the real part.

[0036] The carrier frequency in the x direction and the carrier frequency in the y direction of the off-axis hologram are simulated to generate a reference optical map containing only carrier information.

[0037] Preferably, multiplying the reference optical map containing only carrier information with the original off-axis hologram, and filtering out the high-frequency carrier information through a filtering algorithm to obtain the phase information of the sample to be measured, includes:

[0038] Multiplying the reference optical map containing only carrier information with the original off-axis hologram, and using a mean filter for smoothing interpolation to obtain the phase information of the sample to be measured.

[0039] Preferably, multiplying the reference light containing only carrier information with the original off-axis hologram, and filtering out the high-frequency carrier information through a filtering algorithm to obtain the phase information of the sample to be measured, includes:

[0040] Multiplying the reference optical map containing only carrier information with the original off-axis hologram, and using a bicubic interpolation filter for smoothing interpolation to obtain the phase information of the sample to be measured.

[0041] According to the specific embodiments disclosed by the present invention, a single-frame phase-shifting off-axis digital holographic phase determination device is disclosed in the second aspect of the present invention, including:

[0042] An image preprocessing unit, configured to preprocess the original off-axis hologram containing the information of the sample to be measured to generate an off-axis hologram;

[0043] An image processing unit, configured to process the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase shift amounts;

[0044] An image transformation unit, configured to perform two-dimensional Fourier transform, band-pass 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;

[0045] An image generation unit, configured to simulate and generate a reference optical map 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;

[0046] An image filtering unit, configured to multiply the reference optical map containing only carrier information with the original off-axis hologram, and filter out the high-frequency carrier information through a filtering algorithm to obtain the phase information of the sample to be measured.

[0047] According to the specific embodiments disclosed by the present invention, a third aspect of the present invention discloses a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, it implements the method for editing the content in a document as described in any one of the above.

[0048] According to the specific embodiments disclosed by the present invention, a fourth aspect of the present invention provides an electronic device, including: one or more processors; a storage device for storing one or more programs, and when the one or more programs are executed by the one or more processors, the one or more processors are caused to implement the method for editing the content in a document as described in any one of the above.

[0049] The above solutions disclosed by the present invention, compared with the prior art, have at least the following beneficial effects:

[0050] By using digital phase-shifting technology, the present invention obtains multiple off-axis holograms with different phase shifts, and does not require a high-precision phase shifter, and can achieve high-precision measurement of dynamic samples; the information of the measured sample can be obtained by filtering the multiplied hologram, without phase compensation. Therefore, the algorithm complexity of the present invention is low, saving time and space costs, and only a single-frame image is required to achieve high-quality reconstruction of off-axis digital holography. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the disclosure of the present invention, and are used together with the specification to explain the principles of the disclosure of the present invention. Obviously, the drawings in the following description are only some embodiments of the disclosure of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. In the drawings:

[0052] Figure 1 is a flowchart of a method for determining the phase of single-frame phase-shifted off-axis digital holography provided by the first embodiment of the present invention;

[0053] Figure 2 a is the off-axis hologram obtained in the first embodiment of the present invention;

[0054] Figure 2 b is the first off-axis hologram with a one-pixel upward phase shift;

[0055] Figure 2 c is the second off-axis hologram with a one-pixel leftward shift;

[0056] Figure 2 d is the original complex amplitude result graph containing the real image;

[0057] Figure 2 e is the first complex amplitude result graph containing the real image;

[0058] Figure 2 f is the second complex amplitude result diagram containing the real image;

[0059] Figure 2 g is the result diagram of multiplying the original off-axis hologram by the simulated reference light diagram;

[0060] Figure 2 h is the measured sample information diagram after restoring the phase information;

[0061] Figure 2 i is the original measured sample information;

[0062] Figure 3 It is a schematic diagram of a single-frame phase-shifting off-axis digital holographic phase determination device provided by the second embodiment of the present invention;

[0063] Figure 4 It is a schematic diagram of the structure of an electronic device provided by the third embodiment of the present invention. Detailed implementation manners

[0064] In order to make the objectives, technical solutions and advantages of the disclosure of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments disclosed by the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments disclosed in the present invention without making creative efforts belong to the scope of protection of the disclosure of the present invention.

[0065] The terms used in the disclosed embodiments of 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", "the" and "said" used in the disclosed embodiments of the present invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. "Plural" generally includes at least two.

[0066] It should be understood that although the terms first, second, third, etc. may be used in the disclosed embodiments of the present invention to describe, 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.

[0067] The following combines the attached Figure 1 - Figure 2 The optional embodiments disclosed by the present invention are described in detail.

[0068] Digital phase-shifting technology refers to shifting a digital off-axis hologram by one or several pixels along a direction to obtain multiple off-axis holograms with different phase-shift components. The object phase information containing the carrier is calculated using a recovery algorithm, and then the carrier is removed to obtain the accurate object phase information.

[0069] Band-pass filtering technology is to retain a part of the image information (real image) by selecting a certain range of frequencies in the frequency domain, while filtering out the unnecessary information (conjugate image).

[0070] The first embodiment of the present invention provides a method for determining the phase of single-frame phase-shifting off-axis digital holography, as Figure 1 shown, including the following steps:

[0071] Step S1: Preprocess the original off-axis hologram containing the information of the sample to be measured to generate an off-axis hologram;

[0072] Step S2: Process the off-axis hologram to obtain a first off-axis hologram and a second off-axis hologram with different phase-shift amounts;

[0073] Step S3: Perform two-dimensional Fourier transform, band-pass filtering, and inverse two-dimensional Fourier transform on the off-axis hologram, the first off-axis hologram, and the second off-axis hologram respectively to obtain the original complex amplitude result containing real image information, the first complex amplitude result, and the second complex amplitude result;

[0074] Step S4: Simulate and generate a reference light map 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;

[0075] Step S5: Multiply the reference light map containing only carrier information by the original off-axis hologram, and filter out the carrier information through a filtering algorithm to obtain the phase information of the sample to be measured.

[0076] The present invention uses digital phase-shifting technology and filtering technology, without phase compensation, and only requires a single-frame off-axis hologram to achieve high-quality reconstruction of off-axis digital holography technology.

[0077] Further, the step of preprocessing the original off-axis hologram containing the information of the sample to be measured in step S1 to generate an off-axis hologram includes;

[0078] Step S1-1: Obtain the original off-axis hologram containing the information of the sample to be measured through an off-axis digital holographic device I 0 .

[0079] Step S1-2: Remove the original off-axis hologram I 0Generate an off-axis hologram from the zero-order diffraction image information contained therein I .

[0080] Specifically, the off-axis digital holographic device for obtaining the original off-axis hologram can be the interference pattern of the sample to be measured obtained by the CCD camera in any existing technical device, and there are no restrictions on the system stability and optical path alignment accuracy of the device.

[0081] 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, and the original off-axis hologram obtained at this time I 0 can be expressed as:

[0082] ;

[0083] Among them, a is the DC term; b is the modulation term of the interference fringes; is the phase;

[0084] k x is the carrier frequency of the original off-axis hologram along the x direction;

[0085] k y is the carrier frequency of the original off-axis hologram along the y direction;

[0086] Since the original off-axis hologram I 0 contains the zero-order image and the conjugate image, in a preferred embodiment of the present invention, 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, the off-axis hologram I is obtained, which can be expressed as:

[0087] .

[0088] Step S2, process the off-axis hologram I to obtain a first off-axis hologram and a second off-axis hologram with different phase shift amounts, including the following steps:

[0089] Step S2-1, use digital phase shift technology to move the off-axis hologram in the first direction m pixels to obtain a first off-axis hologram;

[0090] Step S2-2, use digital phase shift technology to move the off-axis hologram in the second direction n pixels to obtain a second off-axis hologram.

[0091] In this step, multiple off-axis holograms with different phase shifts can be obtained only by using digital phase-shifting technology, without the need for a high-precision phase shifter, realizing high-precision measurement of dynamic samples.

[0092] In a preferred embodiment of the present invention, to ensure the fidelity of the phase information,

[0093] Shift the off-axis hologram 1 pixel to the left to obtain the first off-axis hologram:

[0094] ;

[0095] Shift the off-axis hologram 1 pixel upward to obtain the second off-axis hologram:

[0096] 。

[0097] In step S3, perform two-dimensional Fourier transform, band-pass filtering, and inverse two-dimensional Fourier transform on the off-axis hologram to obtain the original complex amplitude result containing real image information C , The expression is:

[0098] ;

[0099] Perform two-dimensional Fourier transform, band-pass filtering, and inverse two-dimensional Fourier transform on the first off-axis hologram to obtain the first complex amplitude result containing real image information as , The expression is:

[0100] ;

[0101] Perform two-dimensional Fourier transform, band-pass filtering, and inverse two-dimensional Fourier transform on the second off-axis hologram to obtain the second complex amplitude result containing real image information , The expression is;

[0102] ;

[0103] In this step, by performing operations such as two-dimensional Fourier transform, band-pass filtering, and inverse two-dimensional Fourier transform, the phase information in the time domain is converted into frequency domain information, so as to use the band-pass filter to extract the real image information, and

[0104] Among them, the time-domain phase information of the off-axis hologram is converted into frequency-domain phase information by performing two-dimensional Fourier transform.

[0105] By using a band-pass filter, the conjugate image in the off-axis hologram is filtered out, so as to extract specific real image information from multiple effective information.

[0106] The extracted real - image information is transformed from the frequency domain to the time domain by performing an inverse two - dimensional Fourier transform.

[0107] Step S4: Simulate and generate a reference optical - map containing only carrier information according to the original complex - amplitude result, the first complex - amplitude result, and the second complex - amplitude result containing real - image information, including the following steps:

[0108] Step S4 - 1: Divide the first complex - amplitude result by the original complex - amplitude result C to obtain the carrier frequency in the x - direction where represents the imaginary part, represents the real part.

[0109] Step S4 - 2: Divide the second complex - amplitude result by the original complex - amplitude result to obtain the carrier frequency in the y - direction where represents the imaginary part, represents the real part.

[0110] Step S4 - 3: Simulate and generate a reference optical - map containing only carrier information from the carrier frequency in the x - direction and the carrier frequency in the y - direction. The expression is:

[0111] ;

[0112] In this step, by dividing the complex - amplitude result by the original complex - amplitude result, the carrier information in only the x and y directions is obtained, and the included phase information and the original carrier - modulation information are eliminated.

[0113] In step S5, multiply the reference optical - map containing only carrier information by the original off - axis hologram. The expression is as follows:

[0114] ,

[0115] In the off - axis hologram, the transformation frequency of the carrier is much greater than the transformation frequency of the object phase. The second term in the above formula is the term containing the carrier - modulation term and is considered to be in the high - frequency region. The first term is the term containing only the phase information of the sample to be measured.

[0116] Further, through a filtering algorithm, the high - frequency phase information is filtered out to obtain the phase information of the sample to be measured.

[0117] Specifically, the phase information of the sample to be measured can be obtained by using a mean filter or a bicubic interpolation filter for smoothing and interpolation.

[0118] Mean filtering is a commonly used image processing technique. Its basic principle is to replace each pixel value in the image with the average value of its neighboring pixel values, mainly used to remove image noise and achieve image smoothing.

[0119] Bicubic interpolation filtering uses the information of known surrounding pixels to estimate the gray value or signal value of the interpolation point. By applying cubic spline interpolation functions in the vertical and horizontal directions, a smooth interpolation effect is achieved, avoiding obvious jaggedness or distortion in the image.

[0120] Example 1

[0121] In this example, the process of determining the phase of an off-axis hologram is simulated using Matlab software. The initial parameters of the simulation image are set as follows: the sampling frequency is 4.8 µm, the amplitude transmittance of the background part is 0.2, the phase is 0 rad, the amplitude transmittance of the line and digital parts is 1, and the phase is -2 rad; the wavelength of the reference light wave is 632.8 nm.

[0122] According to the off-axis hologram expression;

[0123] ,

[0124] Get the off-axis hologram as shown in Figure 2 a.

[0125] Move the off-axis hologram one pixel to the left to obtain the first off-axis hologram, and the generated image is as shown in Figure 2 b;

[0126] Move the off-axis hologram one pixel up to obtain the second off-axis hologram, and the generated image is as shown in Figure 2 c;

[0127] For I , I 1 and I 2 Perform Fourier transform, band-pass filtering, and inverse Fourier transform respectively to obtain the original complex amplitude result C containing real image information: ;

[0128] The first complex amplitude result : ;

[0129] The second complex amplitude result : ;

[0130] They are respectively as shown in Figure 2 d, Figure 2 e and Figure 2 f:

[0131] Divide the above complex amplitude results to obtain the carrier frequencies in the x and y directions respectively: ;

[0132] ;

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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:

[0138] 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;

[0139] 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;

[0140] 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;

[0141] 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;

[0142] An image filtering unit 205 is configured to multiply the reference optical image containing only carrier information with the original off-axis hologram, and filter out the high-frequency carrier information through a filtering algorithm to obtain the phase information of the sample to be measured.

[0143] In a third aspect of the present invention, an electronic device is provided, which includes: 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 to enable the at least one processor to execute the method steps as described in the above embodiments.

[0144] In a fourth aspect of the present invention, a computer-readable storage medium is provided, which stores computer-executable instructions that can execute the method steps as described in the above embodiments.

[0145] Next, refer to Figure 4 , which shows a schematic structural diagram of an electronic device suitable for implementing the disclosed embodiments of the present invention. The terminal device in the disclosed embodiments 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), in-vehicle terminals (such as in-vehicle 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 impose any limitations on the functions and usage scope of the disclosed embodiments of the present invention.

[0146] As Figure 4 shown, the electronic device may include a processing device (such as 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 into a random access memory (RAM) 403. In the RAM 403, various programs and data required for the operation of the electronic device are also stored. The processing device 401, the ROM 402, and the RAM 403 are connected to each other through a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0147] Generally, the following devices may be connected to the I / O interface 405: an input device 406 including, for example, a touch screen, a touchpad, 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 can allow the electronic device to communicate with other devices wirelessly or wiredly to exchange data. AlthoughFigure 4 An electronic device having various devices is shown, but it should be understood that it is not required to implement or have all the shown devices. Instead, more or fewer devices may be implemented or had.

[0148] In particular, according to the embodiments disclosed in the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. 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 codes for performing the methods shown in the flowcharts. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device 409, or installed from a storage device 408, or installed from a ROM 402. When the computer program is executed by a processing device 401, the above functions defined in the methods of the embodiments disclosed in the present invention are performed.

[0149] It should be noted that the above-mentioned computer-readable medium in the present invention can be a computer-readable signal medium or a computer-readable storage medium or any combination of the two. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples of the computer-readable storage medium can include, but are not limited to: an electrical connection having 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, the computer-readable storage medium can be any tangible medium that contains or stores a program, and the program can be used by or in combination with an instruction execution system, apparatus, or device. And in the present invention, the computer-readable signal medium can include a data signal propagated in a baseband or as part of a carrier wave, in which the computer-readable program code is carried. Such a propagated data signal can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer-readable signal medium can also be any computer-readable medium other than the computer-readable storage medium, and the computer-readable signal medium can send, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted by any appropriate medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0150] The above-mentioned computer-readable medium can be included in the above-mentioned electronic device; or it can exist separately and not be assembled into the electronic device.

[0151] Computer program code for performing the operations disclosed in the present invention may be written in one or more programming languages or combinations thereof. The above-mentioned programming languages include object-oriented programming languages such as Java, Smalltalk, C++, and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, executed as a stand-alone 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 it may be connected to an external computer (e.g., connected through the Internet using an Internet service provider).

[0152] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments disclosed in the present invention. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code that contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, may be implemented by a dedicated hardware-based system that performs the specified functions or operations, or may be implemented by a combination of dedicated hardware and computer instructions.

[0153] The units described in the embodiments disclosed in the present invention may be implemented in software or in hardware. Among them, the name of the unit does not constitute a limitation on 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 optical 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; comprising: The reference light image containing only carrier information is multiplied by the original off-axis hologram, and a mean filter or a bicubic interpolation filter is used for smooth interpolation to obtain the phase information of the sample to be measured.

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 I0 containing the information of the sample to be tested is obtained by the off-axis digital holographic device, and the expression is: Among them, a is the DC term; is the phase; b is the modulation term of the interference fringes; k x is the carrier frequency of the original off-axis hologram along the x direction; k y is the carrier frequency of the original off-axis hologram along the y direction; The off-axis hologram I 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: 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.

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 carrier frequency of the off-axis hologram along the x direction, which is expressed as: k x =tan -1 [I m (C1 / C) / R e (C1 / C)]; The second complex amplitude result is divided by the original complex amplitude result to obtain the carrier frequency of the off-axis hologram along the y direction, which is expressed as: k y =tan -1 [I m C2 / C) / R e (C2 / C)]; Among them, C is the original complex amplitude result containing real image information; C1 is the first complex amplitude result containing real image information; C2 is the second complex amplitude result containing real image information; I m represents the imaginary part, R e represents the real part, The carrier frequency of the off-axis hologram along the x direction and the carrier frequency of the off-axis hologram along the y direction are simulated to generate a reference optical pattern containing only carrier information.

6. 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.

7. 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 5 is implemented.

8. 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 5.

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