A single-pixel phase imaging method, system, device and storage medium

Abstract

The application discloses a kind of single-pixel phase imaging method, system, device and storage medium, imaging system includes light source, pre-processing module, first spatial modulator, second spatial modulator, lens, detector, data acquisition card and processor, light emitted by light source collimates and attenuates after pre-processing module, in turn after first spatial modulator, measured object, second spatial modulator and lens, to detector;Imaging method includes: obtaining the first hologram and second hologram of phase difference preset phase shift, according to first hologram, second hologram and pre-design formula, the hologram of measured object is calculated, according to the hologram of measured object and preset algorithm, the reconstructed image of measured object is calculated.The efficiency of the embodiment of the application improves phase shift holographic imaging, and can be widely applied to imaging technical field.

Description

Technical Field

[0001] The present invention relates to the field of imaging technology, and in particular to a single-pixel phase imaging method, system, device and storage medium. Background Art

[0002] Single-pixel imaging is a novel optical computational imaging method. Traditional imaging methods use a two-dimensional array detector to directly acquire images, while single-pixel imaging uses a series of pre-generated masks to encode the target image, and then uses a single-pixel detector to record the total light intensity corresponding to each mask, and finally restores the image through an algorithm. For real objects, in addition to amplitude information, phase information is also included. For objects made of transparent materials, such as cells, obtaining phase information is particularly important. In order to obtain the phase information of the object, single-pixel phase imaging came into being. Currently common single-pixel phase imaging technologies include combining single-pixel imaging with holographic imaging and stacked imaging.

[0003] Currently, commonly used phase-shift holographic imaging techniques include four-step phase shifting, three-step phase shifting, and two-step phase shifting. Four-step phase shifting requires acquiring four holograms, three-step phase shifting requires acquiring three holograms, and two-step phase shifting requires acquiring two holograms as well as intensity maps of the object light and reference light, which requires improvement in efficiency. Summary of the Invention

[0004] In view of this, in order to solve one of the above problems, an object of the embodiments of the present invention is to provide a single-pixel phase imaging method, system, device and storage medium to improve the efficiency of phase-shift holographic imaging.

[0005] In one aspect, an embodiment of the present invention provides a single-pixel phase imaging method, comprising:

[0006] Acquire a first hologram and a second hologram having a preset phase shift difference;

[0007] Calculating a hologram of the object under test according to the first hologram, the second hologram and a preset calculation formula;

[0008] A reconstructed image of the object to be measured is calculated according to the hologram of the object to be measured and a preset algorithm.

[0009] Optionally, calculating the hologram of the object under test according to the first hologram, the second hologram and a preset calculation formula includes:

[0010] determining an average value of a first hologram based on the first hologram, and determining an average value of a second hologram based on the second hologram;

[0011] determining a reference light amplitude according to the first hologram and the second hologram;

[0012] A hologram of the object to be measured is calculated according to the first hologram, the average value of the first holograms, the second hologram, the average value of the second holograms, the reference light amplitude, and the preset calculation formula.

[0013] Optionally, the preset calculation formula is as follows:

[0014]

[0015] Among them, P0 represents the hologram of the object being measured, P r represents the reference light amplitude, I1 represents the first hologram, represents the average value of the first hologram, I2 represents the second hologram, represents the average value of the second hologram.

[0016] Optionally, calculating a reconstructed image of the object under test according to the hologram of the object under test and a preset algorithm includes:

[0017] Calculating a reconstructed image of the object under test based on the hologram of the object under test and an angular spectrum diffraction propagation algorithm;

[0018] or, calculating a reconstructed image of the object under test based on the hologram of the object under test and a Fresnel diffraction propagation algorithm;

[0019] Alternatively, a reconstructed image of the object to be measured is calculated based on the hologram of the object to be measured and a Fourier diffraction propagation algorithm.

[0020] On the other hand, an embodiment of the present invention provides a single-pixel phase imaging system, comprising a light source, a preprocessing module, a first spatial modulator, a second spatial modulator, a lens, a detector, a data acquisition card, and a processor. The light emitted by the light source is collimated and attenuated by the preprocessing module, and then passes through the first spatial modulator, the object to be measured, the second spatial modulator, and the lens in sequence before reaching the detector.

[0021] The first spatial modulator is used to load phase-shift fringes;

[0022] The second spatial modulator is used to load single-pixel code;

[0023] The detector is used to collect light intensity signals;

[0024] The data acquisition card is used to convert the light intensity signal into a hologram corresponding to the digital signal;

[0025] The processor is used to execute the above imaging method.

[0026] Optionally, the first spatial modulator comprises an amplitude spatial light modulator.

[0027] Optionally, the second spatial modulator comprises a digital micromirror device.

[0028] Optionally, the detector comprises a silicon-based multi-pixel photon counter.

[0029] In another aspect, an embodiment of the present invention provides a single-pixel phase imaging device, comprising:

[0030] at least one processor;

[0031] at least one memory for storing at least one program;

[0032] When the at least one program is executed by the at least one processor, the at least one processor implements the above method.

[0033] On the other hand, an embodiment of the present invention provides a computer-readable storage medium storing a program executable by a processor. When the program is executed by the processor, it is used to perform the above method.

[0034] The implementation of the embodiment of the present invention includes the following beneficial effects: in this embodiment, a first hologram and a second hologram with a preset phase shift are first obtained, then a hologram of the object to be measured is calculated based on the first hologram, the second hologram and a preset calculation formula, and finally, a reconstructed image of the object to be measured is calculated based on the hologram of the object to be measured and a preset algorithm. Only two holograms need to be collected to reconstruct a single-pixel phase image of the object to be measured, and there is no need to collect intensity maps of object light or reference light, thereby improving the efficiency of phase-shift holographic imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 1 is a schematic structural diagram of a single-pixel phase imaging system provided by an embodiment of the present invention;

[0036] Figure 2 This is a schematic flow chart of the steps of a single-pixel phase imaging method provided by an embodiment of the present invention;

[0037] Figure 3 This is a schematic flow chart of the steps for calculating a hologram of a measured object provided by an embodiment of the present invention;

[0038] Figure 4 This is a structural block diagram of a single-pixel phase imaging system provided by an embodiment of the present invention;

[0039] Figure 5 This is a structural block diagram of a single-pixel phase imaging device provided by an embodiment of the present invention;

[0040] Figure 6 These are two holograms with preset phase shifts provided by an embodiment of the present invention;

[0041] Figure 7 This is a hologram of a measured object provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The step numbers in the following embodiments are provided for ease of description only and do not limit the order of the steps. The order of execution of the steps in the embodiments can be adaptively adjusted based on the understanding of those skilled in the art.

[0043] See Figure 1 An embodiment of the present invention provides a single-pixel phase imaging system, including a light source M1, a beam expander M2, an attenuation plate M3, a first spatial modulator M4, a measured object M5, a second spatial modulator M6, a lens M7, a detector M8, a data acquisition card M9 and a processor. The light emitted by the light source M1 is collimated by the beam expander M2 and attenuated by the attenuation plate M3, and then passes through the first spatial modulator M4, the measured object M5, the second spatial modulator M6 and the lens M7 in sequence before reaching the detector M8. The data acquisition card M9 collects the hologram detection signal of the detector M8, and the processor processes the collected hologram detection signal.

[0044] The working principle of the single-pixel phase imaging system is as follows: after the light source emits a light beam, it is first collimated by a beam expander, and the attenuation plate reduces the light intensity to an extremely weak light level. The first spatial light modulator loads phase-shifting stripes and generates a phase-shifting hologram through the object, which is transmitted to the second spatial light modulator; the second spatial light modulator loads a series of pre-designed single-pixel codes to modulate the phase-shifting hologram, and the modulated light signal is focused by the lens onto the detector; then the data acquisition card converts the collected light intensity signal into a digital signal, and finally the computer restores the image of the object being measured.

[0045] like Figure 2 As shown, an embodiment of the present invention provides a single-pixel phase imaging method, including:

[0046] S100, obtaining a first hologram and a second hologram having a preset phase shift difference;

[0047] S200, calculating a hologram of the object under test according to the first hologram, the second hologram, and a preset calculation formula;

[0048] S300 , calculating a reconstructed image of the object under test according to the hologram of the object under test and a preset algorithm.

[0049] It should be noted that the preset phase shift between the first hologram and the second hologram is determined according to actual application. For example, the preset phase shift between the first hologram and the second hologram is π / 2. If the phase shift of the first hologram is 0, the phase shift of the second hologram is π / 2. If the phase shift of the first hologram is π, the phase shift of the second hologram is 3π / 2.

[0050] The preset calculation formula and the preset algorithm are determined based on actual application and are not specifically limited in this embodiment. The parameters of the preset calculation formula include relevant data of the first hologram and the second hologram. The parameters of the preset algorithm include relevant parameters of the hologram of the measured object.

[0051] Specifically, first, a first hologram and a second hologram with a preset phase shift are obtained through a data acquisition card, then, a hologram of the object to be measured is calculated based on the first hologram, the second hologram and a preset calculation formula, and finally, a reconstructed image of the object to be measured is calculated based on the hologram of the object to be measured and a preset algorithm.

[0052] Alternatively, as Figure 3 As shown, calculating the hologram of the object under test according to the first hologram, the second hologram and a preset calculation formula includes:

[0053] S210, determining an average value of the first hologram based on the first hologram, and determining an average value of the second hologram based on the second hologram;

[0054] S220, determining the reference light amplitude according to the first hologram and the second hologram;

[0055] S230, calculating a hologram of the object under test according to the first hologram, the average value of the first hologram, the second hologram, the average value of the second hologram, the reference light amplitude, and a preset calculation formula.

[0056] Specifically, first, the average value of the first hologram is calculated based on all values ​​of the first hologram, and the average value of the second hologram is calculated based on all values ​​of the second hologram; then, the first hologram and the second hologram are processed to obtain the reference light amplitude; finally, the first hologram, the average value of the first hologram, the second hologram, the average value of the second hologram and the reference light amplitude are substituted into a preset calculation formula to calculate the hologram of the object under test.

[0057] Optionally, the preset calculation formula is as follows:

[0058]

[0059] Among them, P0 represents the hologram of the object being measured, P r represents the reference light amplitude, I1 represents the first hologram, represents the average value of the first hologram, I2 represents the second hologram, It should be noted that if the hologram is normalized, 2P r =1.

[0060] Optionally, calculating a reconstructed image of the object under test according to the hologram of the object under test and a preset algorithm includes:

[0061] Calculate the reconstructed image of the object under test based on the hologram of the object under test and the angular spectrum diffraction propagation algorithm;

[0062] or, calculating a reconstructed image of the object under test based on the hologram of the object under test and a Fresnel diffraction propagation algorithm;

[0063] Alternatively, a reconstructed image of the object to be measured is calculated based on the hologram of the object to be measured and a Fourier diffraction propagation algorithm.

[0064] Specifically, any one of the angular spectrum diffraction propagation algorithm, the Fresnel diffraction propagation algorithm, or the Fourier diffraction propagation algorithm is used with the hologram of the object to calculate the reconstructed image of the object. Taking the angular spectrum diffraction propagation algorithm as an example, the calculation formula for the reconstructed image of the object is as follows:

[0065]

[0066] O=abs(E)

[0067] Among them, O represents the reconstructed image of the measured object, F represents the inverse Fourier transform, and F -1 represents inverse Fourier transform, P0 represents the hologram of the object being measured, z represents the propagation distance, λ represents the wavelength of the light source, fx and fy represent the frequency domain coordinates, and abs() represents the square of the modulus.

[0068] like Figure 4 As shown, an embodiment of the present invention provides a single-pixel phase imaging system, including:

[0069] The first module is configured to obtain a first hologram and a second hologram having a preset phase shift;

[0070] The second module is used to calculate the hologram of the object under test according to the first hologram, the second hologram and a preset calculation formula;

[0071] The third module is used to calculate the reconstructed image of the object under test based on the hologram of the object under test and a preset algorithm.

[0072] It can be seen that the contents of the above method embodiments are all applicable to the present system embodiments. The functions specifically implemented by the present system embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0073] like Figure 5As shown, an embodiment of the present invention provides a single-pixel phase imaging device, comprising:

[0074] at least one processor;

[0075] at least one memory for storing at least one program;

[0076] When at least one program is executed by at least one processor, the at least one processor implements the above method.

[0077] Among them, the memory is a non-transient computer-readable storage medium that can be used to store non-transient software programs and non-transient computer executable programs. The memory may include a high-speed random access memory and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory optionally includes a remote memory remotely arranged relative to the processor, and these remote memories can be connected to the processor via a network. Examples of the above-mentioned network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network and a combination thereof.

[0078] It can be seen that the contents of the above method embodiments are all applicable to the present device embodiments. The functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0079] In addition, embodiments of the present application further disclose a computer program product or computer program, which is stored in a computer-readable storage medium. A processor of a computer device can read the computer program from the computer-readable storage medium and execute the computer program, causing the computer device to perform the above-described method.

[0080] An embodiment of the present invention further provides a computer-readable storage medium storing a program executable by a processor. When executed by the processor, the program is used to implement the above-described method. Similarly, the contents of the above-described method embodiment are applicable to the present storage medium embodiment. The functions implemented by the present storage medium embodiment are the same as those of the above-described method embodiment, and the beneficial effects achieved are also the same as those achieved by the above-described method embodiment.

[0081] It is understood that all or some steps, systems in the disclosed method above can be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components can be implemented as software by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application specific integrated circuit. Such software can be distributed on a computer-readable medium, and the computer-readable medium can include computer storage media (or non-transitory media) and communication media (or temporary media). As known to those of ordinary skill in the art, the term computer storage medium is included in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data) and is volatile and non-volatile, removable and non-removable media. Computer storage media includes but is not limited to RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disk (DVD) or other optical disk storage, magnetic cassette, magnetic tape, disk storage or other magnetic storage device, or can be used to store desired information and any other medium that can be accessed by a computer. Furthermore, as is well known to those skilled in the art, communication media typically embodies computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0082] On the other hand, in biomedical imaging, phase imaging techniques under extremely weak light conditions must be developed to prevent sample photobleaching and phototoxicity. Current solutions still use single-photon avalanche diodes (SPADs) or photomultiplier tubes (PMTs) to collect light intensity data. These SPADs or PMTs must be coupled with a time-correlated photon counter (TCSPC) to collect data. This combination is costly and complex.

[0083] See Figure 1 An embodiment of the present invention provides a single-pixel phase imaging system, comprising a light source, a preprocessing module, a first spatial modulator, a second spatial modulator, a lens, a detector, a data acquisition card, and a processor. Light emitted by the light source is collimated and attenuated by the preprocessing module, and then passes through the first spatial modulator, the object to be measured, the second spatial modulator, and the lens in sequence before reaching the detector.

[0084] A first spatial modulator, used for loading phase-shifting fringes;

[0085] A second spatial modulator, used for loading single-pixel code;

[0086] A detector for collecting light intensity signals;

[0087] A data acquisition card, used to convert the light intensity signal into a hologram corresponding to the digital signal;

[0088] A processor is used to execute the above imaging method.

[0089] Specifically, the light source is determined based on the actual application and is not specifically limited in this embodiment. For example, a helium-neon laser (wavelength of 632.8 nm) is used. The preprocessing module includes a beam expander and an attenuator. A lens is used to focus the optical signal. The processor can be a different type of electronic device, including but not limited to desktop computers, laptops, wearable devices, and other terminals.

[0090] Optionally, the first spatial modulator comprises an amplitude spatial light modulator.

[0091] Optionally, the second spatial modulator comprises a digital micromirror device.

[0092] Optionally, the detector comprises a silicon-based multi-pixel photon counter.

[0093] This method uses a silicon-based multi-pixel photon counter (MPPC) as a detector to directly read the light intensity signal, avoiding the complex equipment configuration of existing methods that combine single-photon avalanche diodes (SPADs) or photomultiplier tubes (PMTs) with time-correlated photon counters (TCSPCs). It greatly reduces equipment cost and operational complexity, and has significant advantages such as simplicity, high reliability, and high precision.

[0094] The process of the single-pixel phase imaging method is described below with a specific embodiment.

[0095] The HeNe laser is first expanded and collimated by a beam expander, and then reduced to an extremely weak light level by an attenuator. The amplitude spatial light modulator (first spatial modulator) is loaded with a 0-phase-shift fringe pattern and generates a 0-phase-shift hologram through the object being measured, which is then transmitted to a digital micromirror device (second spatial modulator); the digital micromirror device loads Hadamard-based coding to modulate the hologram, and the modulated light signal is focused by a lens onto a multi-pixel photon counter; the data acquisition card converts the collected light intensity signal into a voltage value, which constitutes the Hadamard spectrum coefficient, and then reconstructs the 0-phase-shift hologram through the inverse Hadamard transform, as shown in Figure 2. Figure 6 As shown in (a) in the figure. A π / 2 phase-shifted fringe pattern is then loaded onto the amplitude-type spatial light modulator (first spatial modulator), generating a π / 2 phase-shifted hologram through the object. This hologram is then propagated to the digital micromirror device (second spatial modulator). The digital micromirror device loads the Hadamard basis code to modulate the hologram, and the modulated light signal is focused by the lens onto a multi-pixel photon counter. The data acquisition card converts the collected light intensity signal into a voltage value, which constitutes the Hadamard spectrum coefficient. The π / 2 phase-shifted hologram is then reconstructed through the inverse Hadamard transform, as shown in Figure 1. Figure 6Then, the two phase-shifted holograms are substituted into the reconstruction formula, and the angular spectrum diffraction algorithm is used to reconstruct the object image. The result is as follows: Figure 7 shown.

[0096] It can be seen that the contents of the above method embodiments are all applicable to the present system embodiments. The functions specifically implemented by the present system embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0097] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A single-pixel phase imaging method, characterized in that: include: Acquire a first hologram and a second hologram having a preset phase shift difference; Calculating a hologram of the object under test according to the first hologram, the second hologram and a preset calculation formula; Calculating a reconstructed image of the object under test according to the hologram of the object under test and a preset algorithm; The step of calculating the hologram of the object under test according to the first hologram, the second hologram, and a preset calculation formula includes: determining an average value of a first hologram based on the first hologram, and determining an average value of a second hologram based on the second hologram; determining a reference light amplitude according to the first hologram and the second hologram; Calculating a hologram of the object under test according to the first hologram, the average value of the first holograms, the second hologram, the average value of the second holograms, the reference light amplitude, and the preset calculation formula; The preset calculation formula is as follows: in, represents the hologram of the object being measured, represents the reference light amplitude, represents the first hologram, represents the average value of the first hologram, represents the second hologram, represents the average value of the second hologram.

2. The imaging method according to claim 1, wherein Calculating a reconstructed image of the object under test according to the hologram of the object under test and a preset algorithm includes: Calculating a reconstructed image of the object under test based on the hologram of the object under test and an angular spectrum diffraction propagation algorithm; or, calculating a reconstructed image of the object under test based on the hologram of the object under test and a Fresnel diffraction propagation algorithm; Alternatively, a reconstructed image of the object to be measured is calculated based on the hologram of the object to be measured and a Fourier diffraction propagation algorithm.

3. A single-pixel phase imaging system, characterized in that: The device comprises a light source, a preprocessing module, a first spatial modulator, a second spatial modulator, a lens, a detector, a data acquisition card, and a processor. The light emitted by the light source is collimated and attenuated by the preprocessing module, and then passes through the first spatial modulator, the object to be measured, the second spatial modulator, and the lens in sequence before reaching the detector. The first spatial modulator is used to load phase-shift fringes; The second spatial modulator is used to load single-pixel code; The detector is used to collect light intensity signals; The data acquisition card is used to convert the light intensity signal into a hologram corresponding to the digital signal; The processor is used to execute the imaging method according to any one of claims 1-2.

4. The imaging system according to claim 3, wherein: The first spatial modulator includes an amplitude spatial light modulator.

5. The imaging system according to claim 3, wherein: The second spatial modulator includes a digital micromirror device.

6. The imaging system according to claim 3, wherein: The detector includes a silicon-based multi-pixel photon counter.

7. A single-pixel phase imaging device, characterized in that: include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the method according to any one of claims 1 to 2.

8. A computer-readable storage medium storing a program executable by a processor, characterized in that: The processor-executable program is used to perform the method according to any one of claims 1 to 2 when executed by the processor.

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