Ghost imaging method based on computer-generated holography, computing device and readable storage medium
By combining computational holographic technology and ghost imaging methods, holographic phase maps are generated and high-resolution images are reconstructed, and the resolution of ghost imaging technology is limited is solved, which improves imaging resolution without changing the system structure and expands applicability.
Patent Information
- Application Number
- CN202510940027.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-09
- Publication Date
- 2025-08-15
AI Technical Summary
The spatial resolution of ghost imaging technology is limited by the Rayleigh diffraction limit. The existing methods are difficult to effectively improve the resolution without changing the hardware structure of the imaging system. The traditional methods are not effective or have limited applicability when the imaging distance exceeds the depth Fresnel region.
Combining computational holographic technology and ghost imaging technology, by establishing a matrix set on the object plane and generating a holographic phase map, high-resolution images are reconstructed using Fresnel diffraction formula and second-order correlation function to achieve the modulation of the light intensity distribution of the Fresnel region beyond the depth of the imaging distance.
Without changing the imaging system conditions, the ghost imaging resolution is improved, and it is not limited by the sparsity of the object to be measured, with wider applicability and smaller data processing volume.
Smart Images
Figure CN120491416A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of optical imaging technology, in particular to ghost imaging technology, and specifically to a ghost imaging method, computing device, and readable storage medium based on computational holography. Background Art
[0002] Ghost imaging is a technique that uses the second-order coherence of light to reconstruct the image of the object under test. Its unique imaging mechanism enables imaging under many conditions that are impossible with traditional imaging techniques, such as imaging of obstructed objects, imaging using acoustic waves, and lensless imaging. Currently, ghost imaging has been widely applied in many fields, including lithography, remote sensing imaging, microscopy, and X-ray imaging. However, the spatial resolution of ghost imaging is still limited by the Rayleigh diffraction limit, which in turn restricts the further application of this technology in reality. Therefore, how to improve imaging resolution plays an important role in strengthening the further application of ghost imaging technology in reality.
[0003] Currently, solutions for improving ghost imaging resolution include low-pass filtering ghost imaging, compressed sensing ghost imaging, second-order cumulant ghost imaging, pseudo-inverse ghost imaging, and deep learning ghost imaging. Although these solutions have been widely used and have achieved significant results, they all have limitations. For example, low-pass filtering ghost imaging requires changes to the hardware structure of the imaging system, which in turn results in the loss of ghost imaging's original advantages, such as long-range remote sensing imaging. Compressed sensing ghost imaging has limited effect on improving the imaging resolution of objects that lack sparse characteristics, such as low-contrast and complex grayscale objects. Second-order cumulant ghost imaging includes cross-interference terms in its imaging information, which affects the resolution improvement of this solution. Traditional speckle modulation schemes, such as pseudo-inverse ghost imaging, are difficult to apply when the imaging distance exceeds the deep Fresnel region. As for deep learning ghost imaging, the network model trained on a given dataset can only effectively reconstruct images similar to those in the dataset. Due to its dependence on the training dataset, it may be limited in practical application scenarios and cannot meet the requirements of wide applicability. Summary of the Invention
[0004] A main purpose of the present invention is to overcome at least one of the above-mentioned defects, and to provide a ghost imaging method based on computer holography, which combines computer holography technology with ghost imaging technology, and uses the principle of computer holography to modulate the light intensity distribution on the object plane in the ghost imaging system where the imaging distance exceeds the deep Fresnel region, thereby improving the imaging resolution without changing the imaging system.
[0005] In order to achieve the above object, the technical solution adopted by the present invention is: The present invention provides a ghost imaging method based on computer-generated holography, which includes the following working steps: Step 1: Create a matrix set on the object plane , the object plane is the plane where the object to be measured is located; Step 2: The negative numbers of each matrix in are cleared to zero, and the corresponding positive matrix set is obtained. ; Step 3, respectively The positive numbers of each matrix in are cleared to zero, and the corresponding negative matrix set is obtained. , then Take the absolute value of each negative element in the matrix to achieve Updates; Step 4: and Each matrix in is used as a target pattern, and the corresponding holographic phase image is generated on the light source plane using the computational holography technology. and , get the set and .
[0006] Step 5, Each holographic phase image They are loaded into the spatial light modulator respectively and projected onto the plane of the object to be measured as illumination speckles. The total light intensity of each illumination speckle after transmission (or reflection) is Received by the bucket detector, the set of signals received by the bucket detector is obtained ; Step 6, Each holographic phase image They are loaded into the spatial light modulator and projected onto the plane of the object to be measured as illumination speckles. The total light intensity of each illumination speckle after transmission (or reflection) is Received by the bucket detector, the set of signals received by the bucket detector is obtained ; Step 7, use the Fresnel diffraction formula to calculate and The actual light intensity distribution formed when each holographic phase image propagates to the object plane and , get the set and ; Step 8, use 、 、 and Combined with the second-order correlation function, a high-resolution image of the object to be measured is reconstructed.
[0007] According to one embodiment of the present application, in step 1, a matrix set is established on the object plane. The process includes: Design a dimension on the object plane Orthogonal Matrix ; Will Each row vector in is created as a vector of dimension Matrix , , and get the matrix set .
[0008] According to one embodiment of the present application, the second-order correlation function used in step 8 is Where, is the reconstructed image, and They represent the horizontal and vertical coordinates of the object plane respectively.
[0009] According to one embodiment of the present application, the Fresnel diffraction formula used in step 7 is: Where, and Respectively represent the horizontal and vertical coordinates of the light source plane; and Respectively represent the horizontal and vertical coordinates of the object plane; is the wave vector; is the wavelength of the light source; is the distance between the light source and the object plane.
[0010] According to one embodiment of the present application, in step 7, and Calculate the real light intensity distribution and The formula is .
[0011] In particular, the present invention also provides a computing device, comprising a memory, a processor, and a computer program stored in the memory and executable by the processor, wherein the processor implements the method described above when executing the computer program.
[0012] The present invention also provides a computer-readable storage medium having a computer program stored therein, wherein the computer program implements the above method when executed by a processor. The computer-readable storage medium is preferably a non-volatile readable storage medium.
[0013] Compared with the prior art, the advantages and beneficial effects of the ghost imaging method, computing device, and readable storage medium based on computer-generated holography in the present invention patent application are: The ghost imaging method based on computational holography of the present application combines computational holography technology with ghost imaging technology. By generating a holographic phase map as illumination speckle through computational holography technology, it is possible to modulate the light intensity distribution on the object plane whose imaging distance exceeds the deep Fresnel region. Without changing the imaging system, the imaging resolution is effectively improved through improvements in the processing method. In addition, there is no need to consider whether the object to be measured is sparse, and no training set is required. The data processing volume is relatively small, and therefore, it has wider applicability. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings: Figure 1 Schematic diagram of a ghost imaging system based on a spatial light modulator in the prior art; Figure 2 is a schematic diagram of the working principle of a ghost imaging method based on computer-generated holography according to an embodiment of the present invention; Figure 3 1 is a schematic diagram of a workflow of a ghost imaging method based on computer-generated holography according to an embodiment of the present invention; Figure 4 is an image of an object to be measured in an experimental example according to the present invention, and the dimension of the image is 64*64; Figure 5 is an imaging composition of a ghost imaging method based on computer-generated holography in an experimental example of the present invention; Figure 6 This is a comparison of imaging results using different ghost imaging methods; Figure 7 is a structural diagram of a computing device according to another embodiment of the present application; Figure 8 It is a structural diagram of a computer-readable storage medium according to another embodiment of the present application. DETAILED DESCRIPTION
[0015] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.
[0016] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.
[0017] Ghost imaging (GI), also known as correlation imaging, is an imaging technology that uses the correlation characteristics of light intensity fluctuations to reconstruct the spatial information of objects. Its core idea is to achieve imaging through the correlation measurement of the light intensity fluctuations of two light fields, without the need to directly detect the spatial distribution of the object.
[0018] Computational ghost imaging systems such as Figure 1 As shown, it uses a pseudothermal light source, which is a light source that uses a classical light source (usually a laser) through a specific random modulation method to make its light field statistical characteristics (such as intensity fluctuations) simulate a real thermal light source (such as high-temperature blackbody radiation or a laser passing through a rotating frosted glass). Figure 1 The ghost imaging system shown uses a laser as the primary light source. This laser passes through a spatial light modulator (SLM) to generate a structured light field (such as speckle, Fourier basis, or Hadamard basis). This structured light field forms the optical path of the object. After illuminating the object, the total light intensity is recorded by a bucket detector (also known as a single-pixel detector, such as a photodiode) without spatial resolution. Because the structured light field distribution in the light source plane is predictable, the spatial distribution of the light field formed by the structured light irradiating the object plane can be calculated. The total light intensity transmitted (or reflected) by the object is recorded by the bucket detector without spatial resolution. Finally, a second-order correlation function is established between the calculated object plane light intensity distribution and the measured light intensity received by the bucket detector to reconstruct the object image. The key lies in performing a fluctuation correlation operation using the light intensity distribution on the object plane and the intensity received by the bucket detector to extract the spatial information of the object. Advantages of this method include the absence of lenses, strong anti-interference capabilities, and the ability to penetrate scattering media. However, disadvantages include the requirement for a large amount of sample data and the slow imaging speed. Reducing the number of samples results in poor imaging quality.
[0019] This embodiment describes a ghost imaging method based on computer generated holography, the working principle of which is as follows: Figure 2 As shown, the workflow is as follows Figure 3 Specifically, the following steps may be included: Step 1: Create a matrix set on the object plane , wherein the object plane is the plane where the object to be measured is located, specifically establishing a matrix set The process includes: Design a dimension on the object plane Orthogonal Matrix ; Will Each row vector in is created as a vector of dimension Matrix , , get the matrix set corresponding to the object plane ; Step 2: The negative numbers of each matrix in are cleared to zero, and the corresponding positive matrix set is obtained. ; Step 3, respectively The positive numbers of each matrix in are cleared to zero, and the corresponding negative matrix set is obtained. , then Take the absolute value of each negative element in the matrix to achieve Updates; Step 4: and Each matrix in is used as a target pattern, and the corresponding holographic phase image is generated on the light source plane using the computational holography technology. and , get the set and .
[0020] Step 5, Each holographic phase image They are loaded into the spatial light modulator respectively and projected onto the plane of the object to be measured as illumination speckles. The total light intensity of each illumination speckle after transmission (or reflection) is Received by the bucket detector, the set of signals received by the bucket detector is obtained ; Step 6, Each holographic phase image They are loaded into the spatial light modulator and projected onto the plane of the object to be measured as illumination speckles. The total light intensity of each illumination speckle after transmission (or reflection) is Received by the bucket detector, the set of signals received by the bucket detector is obtained ; Step 7, use the Fresnel diffraction formula to calculate and The actual light intensity distribution formed when each holographic phase image propagates to the object plane and , get the set and ; Step 8, use 、 、 and Combined with the second-order correlation function, a high-resolution image of the object to be measured is reconstructed.
[0021] The Fresnel diffraction formula used in step 7 is: Where, and Respectively represent the horizontal and vertical coordinates of the light source plane; and Respectively represent the horizontal and vertical coordinates of the object plane; is the wave vector; is the wavelength of the light source; is the distance between the light source and the object to be measured.
[0022] In step 7, and Calculate the real light intensity distribution and The formula is .
[0023] The second-order correlation function used in step 8 is Where, is the reconstructed image, and They represent the horizontal and vertical coordinates of the object plane respectively.
[0024] Experimental example: The light source parameters used in the imaging system used in this study are: The wavelength of the light source is , the diameter of the light source is , the pixel size of the light source is The object to be tested is a double-hole object consisting of two transmissive squares, with a side length of The center distance between the two holes is ,like Figure 4 As shown. The object to be measured is placed at a distance of 100 meters from the light source plane. location.
[0025] The following steps are included when generating ghost imaging composition: In the object plane Design a dimension for The Hadamard matrix ; Will Each row vector in is created as a vector of dimension Matrix , , and finally we get a set of 4096 matrices ; Respectively The negative numbers of each matrix in are cleared to zero, and the corresponding positive matrix set is obtained. ; Respectively The positive numbers of each matrix in are cleared to zero, and the corresponding negative matrix set is obtained. , then Take the absolute value of each negative element in the matrix to achieve Updates; Respectively and Each matrix in is used as the target pattern, and the Gerchberg-Saxton algorithm in the computational holography technology is used to generate a Generate the corresponding holographic phase image and , get the set and collection ; Will Each holographic phase image is loaded into the SLM in turn and projected onto the plane of the object to be measured as an illumination speckle. The total light intensity of each illumination speckle after transmission is Received by a bucket detector without spatial resolution, the result is a set of signals received by the bucket detector. ; Will Each holographic phase image is loaded into the SLM in turn and projected onto the plane of the object to be measured as an illumination speckle. The total light intensity of each illumination speckle after transmission is Received by a bucket detector without spatial resolution, the result is a set of signals received by the bucket detector. ; Introduce the Fresnel diffraction formula: The Fresnel diffraction formula is used to calculate and The actual light intensity distribution formed on the object plane and , get the set and , the calculation formula is use 、 、 and Design a second-order correlation function to reconstruct a high-resolution image of the object to be measured. The expression of the second-order correlation function is: According to the above formula To reconstruct the image of the object to be measured, Figure 5 shown.
[0026] In addition, in order to verify the composition effect and technical prominence of this application, the imaging results of the ghost imaging method based on computer holography are compared with those of the traditional ghost imaging technology based on random speckle and the traditional ghost imaging technology based on Hadamard speckle. The comparison results are as follows: Figure 6 It is not difficult to find that the ghost imaging technology based on computer-generated holography in this application is closer to the object to be measured, and has a shorter imaging cycle and higher efficiency.
[0027] In summary, it can be seen that the ghost imaging method based on computational holography of the present application combines computational holography technology with ghost imaging technology, and generates a holographic phase map as illumination speckle through computational holography technology, which can realize the modulation of the light intensity distribution on the object plane where the imaging distance exceeds the deep Fresnel region. Without changing the imaging system, the imaging resolution is effectively improved through improvements in the processing method, and there is no need to consider whether the object to be measured is sparse, nor does it require a training set. The data processing volume is relatively small, and therefore, it has a wider applicability.
[0028] The present application also provides a computing device, referring to Figure 7 The computing device includes a memory 1120, a processor 1110 and a computer program stored in the memory 1120 and capable of being executed by the processor 1110. The computer program is stored in a space 1130 for program code in the memory 1120. When the computer program is executed by the processor 1110, it is implemented to execute any one of the method steps 1131 according to the present invention.
[0029] The present application also provides a computer-readable storage medium. Figure 8 The computer-readable storage medium comprises a storage unit for program code, the storage unit being provided with a program 1131 ′ for executing the method steps according to the present invention, the program being executed by a processor.
[0030] The present application also provides a computer program product comprising instructions. When the computer program product is run on a computer, the computer is caused to execute the steps of the method according to the present invention.
[0031] In the above embodiments, all or part of the embodiments can be implemented using software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When a computer loads and executes the computer program instructions, all or part of the processes or functions described in the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be magnetic media (e.g., floppy disk, hard disk, tape), optical media (e.g., DVD), or semiconductor media (e.g., solid-state drive (SSD)).
[0032] Professionals should also be further aware that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.
[0033] Those skilled in the art will appreciate that all or part of the steps in the above-described embodiment method can be performed by instructing a processor through a program, and the program can be stored in a computer-readable storage medium, which is a non-transitory medium, such as a random access memory, a read-only memory, a flash memory, a hard disk, a solid-state drive, a magnetic tape, a floppy disk, an optical disc, and any combination thereof.
[0034] In particular, the present invention also provides a computing device, comprising a memory, a processor, and a computer program stored in the memory and executable by the processor, wherein the processor implements the method described above when executing the computer program.
[0035] The present invention also provides a computer-readable storage medium having a computer program stored therein, wherein the computer program implements the above method when executed by a processor. The computer-readable storage medium is preferably a non-volatile readable storage medium.
[0036] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable people familiar with this technology to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.
Claims
1. A ghost imaging method based on computer generated holography, characterized in that: The following steps are included: Step 1: Create a matrix set on the object plane ; Step 2: The negative numbers of each matrix in are cleared to zero, and the corresponding positive matrix set is obtained. ; Step 3, respectively The positive numbers of each matrix in are cleared to zero, and the corresponding negative matrix set is obtained. , then Take the absolute value of each negative element in the matrix to achieve Updates; Step 4: and Each matrix in is used as a target pattern, and the corresponding holographic phase image is generated on the light source plane using the computational holography technology. and , get the set and . Step 5, Each holographic phase image They are loaded into the spatial light modulator and projected onto the plane of the object to be measured as illumination speckles. The total light intensity of each illumination speckle after transmission or reflection is Received by the bucket detector, the set of signals received by the bucket detector is obtained ; Step 6, Each holographic phase image They are loaded into the spatial light modulator and projected onto the plane of the object to be measured as illumination speckles. The total light intensity of each illumination speckle after transmission or reflection is Received by the bucket detector, the set of signals received by the bucket detector is obtained ; Step 7, use the Fresnel diffraction formula to calculate and The actual light intensity distribution formed when each holographic phase image propagates to the object plane and , get the set and ; Step 8, use 、 、 and Combined with the second-order correlation function, a high-resolution image of the object to be measured is reconstructed.
2. The ghost imaging method based on computer generated holography according to claim 1, characterized in that: In step 1, a matrix set is established on the object plane. The process includes: Design a dimension on the object plane Orthogonal Matrix ; Will Each row vector in is created as a vector of dimension Matrix , , and get the matrix set .
3. The ghost imaging method based on computer generated holography according to claim 1 or 2, characterized in that: The second-order correlation function used in step 8 is Where, is the reconstructed image, and They represent the horizontal and vertical coordinates of the object plane respectively.
4. The ghost imaging method based on computer generated holography according to claim 1, characterized in that: The Fresnel diffraction formula used in step 7 is: Where, and Respectively represent the horizontal and vertical coordinates of the light source plane; and Respectively represent the horizontal and vertical coordinates of the object plane; is the wave vector; is the wavelength of the light source; is the distance between the light source and the object plane.
5. The ghost imaging method based on computer generated holography according to claim 4, characterized in that: In step 7, and Calculate the real light intensity distribution and The formula is 。 6. A computing device comprising a memory, a processor, and a computer program stored in the memory and executable by the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 5 is implemented. 7 . A computer-readable storage medium having a computer program stored therein, wherein the computer program implements the method according to claim 1 when executed by a processor.