Quantum entangled light spatial correlation imaging method based on iterative deconvolution

Abstract

This invention discloses a quantum entangled light spatial correlation imaging method based on iterative deconvolution, belonging to the field of quantum information. The method includes the following steps: illuminating the target sample with a position-momentum entangled light source, and acquiring multiple frames of entangled light carrying sample information using a single-photon camera; performing statistical operations on the acquired multi-frame images to remove irrelevant background noise and obtain a joint probability distribution image of the sample; extracting the correlation width using the spatial distribution image of the joint probability distribution through differential coordinate projection to construct the point spread function of the optical system; using the point spread function for forward convolution projection and backward error projection, updating the image estimate through iterative calculation until the convergence condition is met to obtain the target sample image. This invention utilizes a camera to image with a position-momentum entangled light source under low illumination conditions, which can obtain high-contrast target imaging and has potential advantages in imaging light-sensitive samples.

Description

Technical Field

[0001] This invention belongs to the field of quantum information, specifically relating to a quantum entangled optical spatial correlation imaging method based on iterative deconvolution. Background Technology

[0002] In traditional classical imaging systems, the core mechanism of image reconstruction stems from the amplitude and phase evolution caused by the interaction between light and matter, achieving detection by capturing the scattering, absorption, or reflection signals of the sample. Depending on the spatial sampling method, it is mainly divided into point-by-point scanning imaging and wide-field imaging: the former has advantages in extracting deep information from static samples, while the latter is more suitable for high-speed dynamic observation. Despite its wide application, the information carrying capacity of classical imaging is limited by resolution and sensitivity. Regarding sensitivity, detection accuracy is limited by photon shot noise under the standard quantum limit; in scenarios of extremely weak light detection or photosensitive sample detection, improving the signal-to-noise ratio often depends on increasing the illumination power, but this can easily cause phototoxic damage to the sample or lead to detector dynamic range saturation. Regarding resolution, limited by the finite aperture of the optical system and the Rayleigh diffraction limit, spatial resolution is always limited to the wavelength range. Furthermore, traditional illumination modes have weak suppression capabilities for ambient stray light, and imaging contrast is easily interfered with in complex backgrounds. Summary of the Invention

[0003] The purpose of this invention is to provide a quantum entangled light spatial correlation imaging method based on iterative deconvolution. By combining the position-momentum correlation characteristics of quantum entangled light, it is possible to image the target object under low light conditions, reduce damage to the target object, and solve the problem of spatial resolution being limited by the diffraction limit and weak noise resistance in the traditional optical field. At the same time, the iterative deconvolution algorithm is combined to further improve the image resolution.

[0004] The technical solution of this invention is:

[0005] A quantum entangled light spatial correlation imaging method based on iterative deconvolution is proposed. This method illuminates a target sample using entangled light sources with position-momentum correlation, and images of the entangled light carrying sample information are captured by a single-photon camera. A large number of frames are acquired using the camera. A joint probability distribution image is calculated. Utilizing the correlation of the entangled light sources, non-correlated background noise can be significantly reduced, achieving signal reconstruction in noisy environments. The correlation width is extracted from the joint probability distribution image through differential coordinate projection and used as the point spread function of the system. Furthermore, the obtained joint probability distribution image is used as an initial estimation image. The target object image is then reconstructed using an iterative deconvolution algorithm.

[0006] The beneficial effects of this invention are as follows:

[0007] Compared to traditional classical illumination, entangled light imaging exhibits higher second-order photon correlation, significantly improving the imaging's noise resistance. Iterative deconvolution algorithms can further enhance image resolution. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the method of the present invention. Detailed Implementation

[0009] The technical principles and solutions of the present invention will now be described in detail with reference to the accompanying drawings:

[0010] like Figure 1 As shown, a quantum entangled light spatial correlation imaging method based on iterative deconvolution is presented. The method employs a target sample illuminated by a position-momentum entangled light source. Entangled light carrying target sample information is captured in multiple frames by a single-photon camera. Statistical operations are performed on the acquired images to obtain the joint probability distribution image of the target sample. The spatial distribution of the joint probability distribution is used to extract the correlation width through differential coordinate projection, constructing the point spread function (PSF) of the optical system. Forward convolution projection and backward error projection are performed using the PSF, and the image estimate is updated iteratively until the convergence condition is met, thereby obtaining the target sample image. The details are as follows:

[0011] S1. The target sample is illuminated using a position-momentum entangled light source, and the image is projected onto the detection plane of a single-photon camera via an optical system. Assume the spatial intensity distribution of the target sample is as follows: The point spread function of the optical system is Then the emphasis of each pixel in the planar image detected by a single-photon camera can be expressed as:

[0012] ;

[0013] Due to environmental noise and detector electronic noise, the actual output observation intensity of each pixel of a single-photon camera can be expressed as:

[0014] ;

[0015] in, These are the pixel coordinates. This refers to the noise introduced during the imaging process.

[0016] S2. Acquire multiple frames of images and denoise the observed images by calculating the joint probability distribution image. The calculation process is as follows:

[0017] A camera takes N images with a fixed exposure time, and the pixel count can be measured. Average intensity value at :

[0018] ;

[0019] Furthermore, in pixels and The product of the average strength measured between them can be expressed as:

[0020] ;

[0021] The first The pixel values ​​in the image are related to the first Multiplying the pixel values ​​in the images and averaging them over the entire set yields:

[0022] ;

[0023] Furthermore, the joint probability distribution image can be obtained:

[0024] ;

[0025] in, This represents an estimate of the average value of the intensity products between images in the same frame. Indicates different frames of images and The average value of the intensity product between the two values ​​is estimated. This yields the denoised image. .

[0026] S3. Project the joint probability distribution image using differential coordinates and perform Gaussian fitting to extract the correlation width as the point spread function of the optical system. .

[0027] S4, the obtained As the initial estimation map for iterative deconvolution .

[0028] S5. Initial estimation map With effective point spread function Perform convolution operations:

[0029] ;

[0030] S6, Calculation error ratio :

[0031] ;

[0032] S7. Calculate the correction factor by performing convolution operation on back projection:

[0033] ;

[0034] S8, Update Image:

[0035] ;

[0036] S9. A new image estimate is obtained in each iteration. Then, calculate the result compared to the previous iteration. relative rate of change :

[0037] ;

[0038] When it is less than the convergence precision Stop the iteration, output the final image, and if it does not meet the requirements, return to S5 to continue the iteration.

[0039] Furthermore, the quantum entangled optical spatial correlation imaging method based on iterative deconvolution is characterized by employing multi-frame averaging for image acquisition to suppress random noise. The "averaging of adjacent frame products" estimation further reduces noise introduced by camera magnification gain fluctuations.

[0040] Furthermore, the quantum entangled optical spatial correlation imaging method based on iterative deconvolution is characterized in that the imaging system consists of a position-momentum entangled light source, a target imaging module, and a correlation measurement and image reconstruction module.

[0041] Furthermore, the aforementioned quantum entangled optical spatial correlation imaging method based on iterative deconvolution is characterized in that the entangled source includes a continuous-wave pump laser, a pump filter, and a nonlinear optical crystal. The continuous-wave pump laser is used to generate pump light with a preset center wavelength and spectral characteristics; the pump filter is a narrow-band filter that selectively filters and controls the bandwidth of the output spectrum of the continuous-wave pump laser to meet the conversion conditions of the nonlinear optical crystal; the nonlinear optical crystal can be a type I or type II nonlinear crystal, i.e., a BBO or PPKTP crystal, used to generate position-momentum entangled photon pairs that satisfy energy and momentum conservation.

[0042] Furthermore, a quantum entangled optical spatial correlation imaging method based on iterative deconvolution is characterized in that: the target imaging module includes an imaging lens group and a filter group. The imaging lens group is a 4-f imaging system with the two-dimensional Fourier transform characteristics of an ideal lens, ensuring the integrity of the sample spatial frequency distribution and imaging quality. Further, the filter group is composed of a narrowband bandpass filter and a high-pass filter, and is placed in the frequency plane and imaging path of the 4-f imaging system to suppress pump light residue, ambient scattered light, and system stray light, thereby improving the signal-to-noise ratio of the optical system.

[0043] Furthermore, the quantum entangled optical spatial correlation imaging method based on iterative deconvolution is characterized in that the correlation measurement and image reconstruction module includes a single-photon detection camera and a host computer. The single-photon camera can be an sCMOS camera, an EMCCD camera, or an ICCD camera, used to acquire data on the arrival position, arrival time, and intensity distribution of photons from the position-momentum entangled light source after passing through the imaging target. The host computer can be a computer, microcontroller, ARM, DSP, FPGA, GPU, or ASIC device, etc., receiving data from the single-photon camera and performing correlation analysis, statistical processing, and image reconstruction.

[0044] This invention discloses a quantum entangled light spatial correlation imaging method based on iterative deconvolution, belonging to the field of quantum information. It employs a position-momentum entangled light source to illuminate the target sample, and the entangled light carrying sample information is captured in multiple frames by a single-photon camera. Statistical operations are performed on the acquired images to remove irrelevant background noise, obtaining a joint probability distribution image of the sample. The spatial distribution of this joint probability distribution image is used to extract the correlation width through differential coordinate projection, constructing the point spread function (PSF) of the optical system. The PSF is then used for forward convolution projection and backward error projection, and the image estimate is updated iteratively until a convergence condition is met, thereby obtaining a high-resolution image of the target sample. This invention utilizes a position-momentum entangled light source for imaging under low illumination conditions, achieving high-contrast target imaging, and has potential advantages in imaging light-sensitive samples.

Claims

1. A quantum entangled optical spatial correlation imaging method based on iterative deconvolution, characterized in that, The target sample is illuminated by a position-momentum entangled light source, and the entangled light carrying the target sample information is captured in multiple frames by a single-photon camera. Statistical operations are performed on the acquired images to obtain the joint probability distribution image of the target sample. The spatial distribution of the joint probability distribution is used to extract the correlation width through differential coordinate projection, constructing the point spread function of the optical system. The point spread function is then used for forward convolution projection and backward error projection, and the image estimate is updated iteratively until the convergence condition is met, thereby obtaining the target sample image. Specifically, as follows: S1. Illuminate the target sample using a position-momentum entangled light source, and image the image onto the detection plane of a single-photon camera via an optical system; let the spatial intensity distribution of the target sample be... The point spread function of the optical system is Then the emphasis of each pixel in the planar image detected by a single-photon camera can be expressed as: ； Due to environmental noise and detector electronic noise, the actual output observation intensity of each pixel of a single-photon camera can be expressed as: ； in, These are the pixel coordinates. This refers to noise introduced during the imaging process; S2. Acquire multiple frames of images and denoise the observed images by calculating the joint probability distribution image. The calculation process is as follows: A camera takes N images with a fixed exposure time, and the pixel count can be measured. Average intensity value at : ； Furthermore, in pixels and The product of the average strength measured between them can be expressed as: ； The first The pixel values ​​in the image are related to the first Multiplying the pixel values ​​in the images and averaging them over the entire set yields: ； Furthermore, the joint probability distribution image can be obtained: ； in, This represents an estimate of the average value of the intensity products between images in the same frame. Indicates different frames of images and The average value of the intensity product between the elements is estimated, thus yielding the denoised image. ; S3. Project the joint probability distribution image using differential coordinates and perform Gaussian fitting to extract the correlation width as the point spread function of the optical system. ; S4, the obtained As the initial estimation map for iterative deconvolution ; S5. Initial estimation map With effective point spread function Perform convolution operations: ； S6, Calculation error ratio : ； S7. Calculate the correction factor by performing convolution operation on back projection: ； S8, Update Image: ； S9. A new image estimate is obtained in each iteration. Then, calculate the result compared to the previous iteration. relative rate of change : ； When it is less than the convergence precision Stop the iteration, output the final image, and if it does not meet the requirements, return to S5 to continue the iteration.

2. The quantum entangled optical spatial correlation imaging method based on iterative deconvolution according to claim 1, characterized in that, Image acquisition employs multi-frame averaging to suppress random noise, and uses "adjacent frame product averaging" estimation to further reduce noise introduced by camera magnification gain fluctuations.

3. The quantum entangled optical spatial correlation imaging method based on iterative deconvolution according to claim 2, characterized in that, The imaging system consists of a position-momentum entangled light source, a target imaging module, and a correlation measurement and image reconstruction module.

4. The quantum entangled optical spatial correlation imaging method based on iterative deconvolution according to claim 3, characterized in that, The entangled source includes a continuous-wave pumped laser, a pump filter, and a nonlinear optical crystal. The continuous-wave pumped laser is used to generate pump light with a preset center wavelength and spectral characteristics. The pump filter is a narrowband filter that selectively filters and controls the bandwidth of the output spectrum of the continuous-wave pumped laser to meet the conversion conditions of the nonlinear optical crystal. The nonlinear optical crystal can be a type I or type II nonlinear crystal, i.e., a BBO or PPKTP crystal, used to generate position-momentum entangled photon pairs that satisfy the conservation of energy and momentum.

5. The quantum entangled optical spatial correlation imaging method based on iterative deconvolution according to claim 3, characterized in that: The target imaging module includes an imaging lens group and a filter group; the imaging lens group is a 4-f imaging system with Fourier transform characteristics to ensure the integrity of the sample spatial frequency distribution and imaging quality; furthermore, the filter group is composed of a narrowband bandpass filter and a high-pass filter, and is placed in the frequency plane and imaging path of the 4-f imaging system to suppress pump light residue, ambient scattered light and system stray light, and improve the signal-to-noise ratio of the optical system.

6. The quantum entangled optical spatial correlation imaging method based on iterative deconvolution according to claim 3, characterized in that, The correlation measurement and image reconstruction module includes a single-photon detection camera and a host computer. The single-photon camera can be at least one of an sCMOS camera, an EMCCD camera, or an ICCD camera, and is used to acquire data on the arrival position, arrival time, and intensity distribution of photons from a position-momentum entangled light source after passing through the imaging target. The host computer includes at least one of a computer, a microcontroller, an ARM processor, a DSP, an FPGA, a GPU, or an ASIC device, and is used to receive data from the single-photon camera for correlation analysis, statistical processing, and image reconstruction.

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