Cross-band correlated imaging system and method based on optical calculation

Abstract

The invention provides a cross-band correlated imaging system and method based on optical calculation. The system comprises a single-pixel measurement module, an electrical feedback module and an optical calculation intensity correlation module. The single-pixel measurement module measures the total light intensity of the target to be measured after spatial light modulation and coding; the electrical feedback module processes the total light intensity signal and electrically feeds back the total light intensity signal to the second light source to enable the second light source to generate illumination light with corresponding intensity; the light calculation intensity correlation module modulates and encodes the illumination light, and integrates light wave intensity distribution through the array detector to reconstruct a target image to be detected. According to the method, the signal modulation capability and the correlation demodulation characteristic of the correlation imaging technology are fused, and the electrical feedback and optical calculation intensity correlation decoding technology are combined, so that the correlation imaging can perform cross-band imaging on the to-be-detected target in a complex scene.

Description

Technical Field

[0001] This application relates to the field of correlated imaging technology, and particularly to a cross-band correlated imaging system and method based on optical computing. Background Art

[0002] Traditional optical imaging technology relies on array detectors, such as charge-coupled device (CCD), complementary metal oxide semiconductor (CMOS), etc., to obtain spatial resolution information. It is one of the most important ways for humans to obtain images at present. However, in some complex scenarios, such as extremely low-light scenarios, strong scattering light scenarios, non-visible light band scenarios, etc., traditional imaging technology will face problems such as too high detector cost, low detection sensitivity, immature technology resulting in poor imaging quality or even inability to image. Correlated imaging technology, with its characteristic of achieving imaging through mask sequence modulation and correlation demodulation, has the imaging ability to penetrate clouds and distinguish objects clearly, and can meet the general requirements for imaging in the above complex scenarios. However, there are still many deficiencies in actual imaging applications, specifically as follows:

[0003] Insufficient imaging ability. Currently, the mainstream correlated imaging technology is still the traditional spatial light modulation coding combined with computer post-processing reconstruction. This method faces a trade-off between measurement time and reconstruction quality, that is, generally, more spatial light modulation times will obtain better correlation reconstruction effects, but it takes more time for modulation, thus reducing the real-time performance of correlated imaging. In addition, if fewer spatial light modulation times are used, better algorithms (such as compressive sensing, deep learning, etc.) need to be used for image reconstruction, which will face problems such as long calculation time, insufficient algorithm generalization, large storage overhead, and limited transmission bandwidth, thus affecting the timeliness of correlated imaging.

[0004] Poor imaging compatibility in complex scenarios. Existing correlated imaging technology is usually designed only for a specific situation (such as a specific band range or a specific light intensity level, etc.), lacking the ability of cross-band (here, cross-band means spanning a certain physical quantity range) imaging such as cross-bandwidth and cross-light intensity. In actual applications, the situation is often complex and changeable, and the capabilities of sensor devices are limited. In some band ranges and some light intensity levels, array detection is difficult to achieve, and relying on multiple independent correlated imaging systems to achieve multi-band and multi-light intensity level imaging will inevitably cause device redundancy and a multiple increase in detection cost, and at the same time limit the flexibility of correlated imaging applications.

[0005] Due to the above limitations, it is difficult for existing correlation imaging technologies to achieve cross-band imaging of the target to be measured. Therefore, there is an urgent need for a technical solution that can solve the above problems to promote the application of correlation imaging in some more challenging extreme environments. Summary of the Invention

[0006] In view of this, the embodiments of the present application provide a cross-band correlation imaging system and method based on optical computing. By fusing the signal modulation ability and correlation demodulation characteristics of correlation imaging technology, and combining electrical feedback and optical computing intensity correlation decoding technology, correlation imaging can perform cross-band imaging of the target to be measured in complex scenarios (such as extremely weak light, strong scattering, imaging band in the non-visible light band, etc.).

[0007] The technical solution of the embodiments of the present application is implemented as follows:

[0008] In a first aspect, the embodiments of the present application provide a cross-band correlation imaging system based on optical computing. The system includes: a single-pixel measurement module, an electrical feedback module, and an optical computing intensity correlation module;

[0009] The single-pixel measurement module includes a first light source, a first spatial light modulator, and a total light intensity detector. The first light source is used to irradiate the target to be measured. The first spatial light modulator is used to perform spatial light modulation encoding on the target to be measured. The total light intensity detector is used to measure the total light intensity value of the target to be measured after spatial light modulation encoding;

[0010] The electrical feedback module includes a signal processing unit and a second light source. The signal processing unit is used to perform analog-to-digital conversion, signal amplification, and specific function operations on the analog signal output by the total light intensity detector. The second light source is used to generate illumination light with an emission intensity that has a specific functional relationship with the captured total light intensity value according to the drive signal output by the signal processing unit;

[0011] The optical computing intensity correlation module includes a second spatial light modulator and an array detector. The second spatial light modulator is used to modulate the illumination light output by the second light source. The array detector is used to decode and reconstruct the cross-band image of the target to be measured by integrating the light wave intensity distribution modulated by the second spatial light modulator.

[0012] In a second aspect, the embodiments of the present application further provide a cross-band correlation imaging method based on optical computing. The method includes:

[0013] Irradiate the target to be measured with a first light source, construct a modulation matrix, generate a preset number of modulation masks, and load the generated modulation masks onto the first spatial light modulator, so that the first spatial light modulator displays the modulation masks at a preset switching frequency, and synchronously capture the total light intensity value through the total light intensity detector;

[0014] Input the total light intensity value into a signal processing unit for analog-to-digital conversion, signal amplification, and specific function operations to obtain a driving signal, and input the driving signal into a second light source to cause the second light source to generate illumination light whose emission intensity has a specific functional relationship with the captured total light intensity value;

[0015] Irradiate the illumination light output by the second light source onto a second spatial light modulator to achieve spatial light modulation encoding, collect the light field modulated and encoded by the second spatial light modulator through an array detector with a preset integration time, and determine the integral image recorded by the array detector as the object image obtained by cross-band light calculation intensity correlation decoding; wherein, the second spatial light modulator and the first spatial light modulator are loaded with modulation masks of the same sequence, and the integration process of the integral image is used to achieve cross-band light calculation intensity correlation;

[0016] Perform post-processing on the object image to improve the image quality; the post-processing includes but is not limited to using relevant algorithms or filters.

[0017] The embodiments of the present application have the following beneficial effects:

[0018] By fusing the signal modulation ability and correlation demodulation characteristics of correlation imaging technology, combining electrical feedback and optical calculation intensity correlation decoding technology, correlation imaging can perform cross-band imaging on a target to be measured in complex scenarios (such as extremely weak light, strong scattering, imaging band in the non-visible light band, etc.).

[0019] Specifically, on the one hand, the embodiments of the present application use optical calculation to achieve device-level intensity correlation decoding, breaking the convention that traditional correlation imaging technology needs to use a computer for image post-processing and reconstruction. Instead, it directly realizes intensity correlation by using the integration process of an array detector. The integral image recorded by the array detector is the object image obtained by cross-band light calculation decoding, and cross-band imaging on the target to be measured can be realized in the above complex scenarios. In addition, through the use of a clever structured modulation mask construction, the contribution of the modulation mask to image reconstruction is enhanced, thereby enhancing the quality of the reconstructed image. That is, the technical solution corresponding to the embodiments of the present application significantly increases the imaging performance while ensuring the quality of image reconstruction, and at the same time, the embodiments of the present application have almost zero computational burden and imaging bandwidth limitations.

[0020] On the other hand, the embodiments of the present application utilize electrical feedback technology to enable correlation imaging to achieve compatibility with various complex scenarios. Specifically, the total light intensity signal function after spatial light modulation encoding is collected and converted into illumination light of corresponding intensity for subsequent cross-band optical calculation intensity correlation decoding. This enables the correlation imaging system designed based on this solution to be no longer only applicable to a specific situation (such as a specific wavelength band range or a specific light intensity level, etc.), but can achieve cross-band (here, cross-band means crossing a certain physical quantity range) correlation imaging across wavelength bands, light intensities, etc., and no longer requires multiple independent systems to achieve this function. Thus, it significantly reduces the hardware redundancy and detection cost, and also greatly enhances the application flexibility of correlation imaging, enabling it to flexibly cope with various complex, changeable, and even extreme imaging environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 It is a schematic diagram of the overall process of the cross-band correlation imaging method based on optical calculation provided by the embodiments of the present invention;

[0023] Figure 2 It is a schematic diagram of the overall structure of the cross-band correlation imaging system based on optical calculation provided by the embodiments of the present invention;

[0024] Figure 3 It is a schematic diagram of the image post-processing sub-module in the optical calculation intensity correlation module of the cross-band correlation imaging system based on optical calculation provided by the embodiments of the present invention;

[0025] Figure 4 It is a schematic diagram of the overall structure of the cross-light intensity correlation imaging system based on optical calculation provided by the embodiments of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application in conjunction with the accompanying drawings in the embodiments of this application. It should be understood that the accompanying drawings in this application are only for the purposes of illustration and description, and are not used to limit the protection scope of this application. Additionally, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate the operations implemented according to some embodiments of this application. It should be understood that the operations in the flowchart may not be implemented in sequence, and steps without a logical context relationship may be reversed in order or implemented simultaneously. Furthermore, those skilled in the art can add one or more other operations to the flowchart or remove one or more operations from the flowchart under the guidance of the content of this application.

[0027] In the following description, reference is made to "some embodiments", which describe a subset of all possible embodiments. However, it can be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments, and can be combined with each other without conflict.

[0028] In addition, the described embodiments are only some embodiments of this application, rather than all embodiments. The components of the embodiments of this application usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of this application to be protected, but merely represents the selected embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of this application.

[0029] In the following description, the terms "first / second / third" involved are only used to distinguish similar objects and do not represent a specific order for the objects. It can be understood that "first / second / third" can be interchanged with a specific order or sequence when allowed, so that the embodiments of this application described here can be implemented in an order other than that illustrated or described here.

[0030] It should be noted that the term "including" will be used in the embodiments of this application to indicate the existence of the features stated thereafter, but does not exclude the addition of other features.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used herein are for the purpose of describing the embodiments of this application and do not limit this application.

[0032] An embodiment of the present application provides a cross-band correlation imaging system based on optical computing. The system includes: a single-pixel measurement module, an electrical feedback module, and an optical computing intensity correlation module;

[0033] The single-pixel measurement module includes a first light source, a first spatial light modulator, and a total light intensity detector. The first light source is used to irradiate the target to be measured. The first spatial light modulator is used to perform spatial light modulation encoding on the target to be measured. The total light intensity detector is used to measure the total light intensity value of the target to be measured after spatial light modulation encoding;

[0034] The electrical feedback module includes a signal processing unit and a second light source. The signal processing unit is used to perform analog-to-digital conversion, signal amplification, and specific function operations on the analog signal output by the total light intensity detector. The second light source is used to generate illumination light with an emission intensity that has a specific functional relationship with the captured total light intensity value according to the drive signal output by the signal processing unit;

[0035] The optical computing intensity correlation module includes a second spatial light modulator and an array detector. The second spatial light modulator is used to modulate the illumination light output by the second light source. The array detector is used to decode and reconstruct the cross-band image of the target to be measured by integrating the light wave intensity distribution modulated by the second spatial light modulator.

[0036] In some embodiments, the cross-band correlation imaging characterization can perform correlation imaging across the range of physical quantities, and the spatial light modulation encoding of the single-pixel measurement module implemented before or after the object to be measured does not affect the correlation imaging result; the physical quantities include, but are not limited to, the wavelength of light and the intensity of light;

[0037] When implementing cross-band optical computing correlation imaging, cross-band optical computing correlation imaging is achieved by selecting the first light source and the second light source, the total light intensity detector, and the array detector with different wavelength ranges;

[0038] When implementing cross-light-intensity optical computing correlation imaging, cross-light-intensity optical computing correlation imaging is achieved by selecting the first light source and the second light source with different powers or light fluxes, and the total light intensity detector and the array detector with different detection sensitivities.

[0039] In some embodiments, the modulation masks loaded by the first spatial light modulator and the second spatial light modulator are masks capable of implementing spatial light modulation. The modulation masks include, but are not limited to, Hadamard basis modulation masks, Vandermonde matrix basis modulation masks, Fourier basis modulation masks, discrete cosine basis modulation masks, Gaussian / sub-Gaussian distribution basis modulation masks, Poisson / sub-Poisson distribution basis modulation masks, random matrix basis modulation masks, Toeplitz matrix basis modulation masks, Hankel matrix basis modulation masks, orthogonal basis modulation masks, and sparse basis modulation masks.

[0040] In some embodiments, when the modulated lights in the single-pixel measurement module and the optical computing intensity correlation module do not interfere with each other, the first light source and the second light source share the same one, and the first spatial light modulator and the second spatial light modulator share the same one.

[0041] If the first spatial light modulator and the second spatial light modulator are not the same one, the first spatial light modulator and the second spatial light modulator control the timing error within the tolerance range through a connection synchronization control unit.

[0042] In some embodiments, the total light intensity detector includes a point detector or a bucket detector; the integration time of the array detector is adjusted as needed.

[0043] See Figure 1 , Figure 1 is the overall flowchart of the cross-band correlation imaging method based on optical computing provided by the embodiments of the present invention, steps S101 - S104.

[0044] S101, single-pixel measurement.

[0045] Irradiate the target to be measured with the first light source, construct a modulation matrix, generate a preset number of modulation masks, and load the generated modulation masks onto the first spatial light modulator, so that the first spatial light modulator displays the modulation masks at a preset switching frequency, and synchronously capture the total light intensity value through the total light intensity detector.

[0046] S102, electrical feedback.

[0047] Input the total light intensity value into the signal processing unit for analog-to-digital conversion, signal amplification, and specific function operations to obtain a drive signal, and input the drive signal into the second light source, so that the second light source generates illumination light whose emission intensity has a specific functional relationship with the captured total light intensity value.

[0048] S103, optical computing intensity correlation.

[0049] Irradiate the illumination light output by the second light source onto the second spatial light modulator to achieve spatial light modulation encoding. Collect the light field modulated and encoded by the second spatial light modulator through an array detector with a preset integration time, and determine the integrated image recorded by the array detector as the object image obtained by cross-band optical computational intensity correlation decoding; wherein, the second spatial light modulator and the first spatial light modulator are loaded with modulation masks of the same sequence, and the integration process of the integrated image is used to achieve cross-band optical computational intensity correlation.

[0050] S104, Image post-processing.

[0051] Perform post-processing on the object image to improve the image quality; the post-processing includes but is not limited to using relevant algorithms or filters.

[0052] In some embodiments, the cross-band correlation imaging characterization can perform correlation imaging across a range of physical quantities, and the spatial light modulation encoding of the single-pixel measurement module implemented before or after the object to be measured does not affect the correlation imaging result; the physical quantities include but are not limited to the wavelength and intensity of light.

[0053] When performing cross-band optical computational correlation imaging, achieve cross-band optical computational correlation imaging by selecting the first light source and the second light source with different wavelength ranges, the total light intensity detector, and the array detector.

[0054] When performing cross-light intensity optical computational correlation imaging, achieve cross-light intensity optical computational correlation imaging by selecting the first light source and the second light source with different powers or light fluxes, and the total light intensity detector and the array detector with different detection sensitivities.

[0055] The cross-band optical computational correlation imaging characterizes that the signal acquisition of the single-pixel measurement module and the integral decoding process of the optical computational intensity correlation module are respectively implemented within different band ranges, including non-visible band to visible band or non-array measurable band to array measurable band.

[0056] The cross-light intensity optical computational correlation imaging characterizes that the signal acquisition of the single-pixel measurement module and the integral decoding process of the optical computational intensity correlation module are respectively implemented under different light intensities, including weak light, single-photon target signal to strong light array detection.

[0057] In some embodiments, the modulation masks loaded by the first spatial light modulator and the second spatial light modulator are masks capable of implementing spatial light modulation. The modulation masks include, but are not limited to, Hadamard basis modulation masks, Vandermonde matrix basis modulation masks, Fourier basis modulation masks, discrete cosine basis modulation masks, Gaussian / sub-Gaussian distribution basis modulation masks, Poisson / sub-Poisson distribution basis modulation masks, random matrix basis modulation masks, Toeplitz matrix basis modulation masks, Hankel matrix basis modulation masks, orthogonal basis modulation masks, and sparse basis modulation masks.

[0058] In some embodiments, the electrical feedback module further includes, but is not limited to, screening the total light intensity value using the consistency imaging mechanism in correlation imaging, and then performing modulation mask gating on the modulation mask sequence loaded by the second spatial light modulator. Alternatively, the driving signal and the total light intensity value satisfy a specific functional relationship through an objective function, and the objective function includes, but is not limited to, one of high-order type, exponential type, logarithmic type, triangular type, and differential type.

[0059] In some embodiments, the electrical feedback module and the second light source need to be calibrated, including but not limited to the following methods:

[0060] Using a standard target object, fitting and correcting the total light intensity value output by the single-pixel measurement module and the illumination light output by the electrical feedback module.

[0061] Next, the processes of correlation imaging for the ranges of physical quantities across the embodiments of the present application will be explained separately, specifically including cross-band optical calculation correlation imaging and cross-light-intensity optical calculation correlation imaging.

[0062] Now, an embodiment of the present invention - a cross-band correlation imaging system and method based on optical calculation will be described in detail. The overall structural schematic diagram of the system is as Figure 2 shown. Next, each module in the above process will be described in combination with Figure 2 Single-pixel measurement module, the composition of this module is included in

[0063] Figure 2 Figure 2 as Figure 2As shown, this module consists of a first light source 1 (a halogen lamp is selected in this embodiment, model SLS202L, with a light emission band of 450 - 5500 nm, a peak wavelength of 1500 nm, and a light emission power of 7.2 W), a band-pass filter (model FKB-VIS-10 is selected in this embodiment, with a central wavelength of 800 nm and a bandwidth of 10 nm) 2, a target to be measured 3, a first spatial light modulator 4 (a digital micromirror device (DMD) is selected as the spatial light modulator in this embodiment, denoted as DMD1, model DLP9500), and a total light intensity detector 5 (a photodiode with a detection band belonging to the near-infrared band is selected in this embodiment, model HS-PD1000-2).

[0064] Generate a Hadamard matrix of N orders (taking N = 1024 as an example) through a computer (this is also an example and is not limited to this Hadamard matrix). Each row of it is called a basis. Optimize and sort the bases, and then recombine each basis into a modulation mask of 32×32 pixels (the product is N). 1024 modulation masks are obtained for spatial light modulation encoding of the target to be measured.

[0065] After generating the modulation masks, display these modulation masks through the first spatial light modulator 4 (DMD1) at a frequency of 22 kHz (for this embodiment). Then, use the light generated by the first light source 1 to extract 800 nm (for this embodiment) near-infrared illumination light through the band-pass filter 2. After that, the near-infrared light irradiates the object to be measured 3, and the reflected light beam then irradiates the first spatial light modulator 4 (DMD1) with the modulation mask loaded to achieve spatial light modulation encoding. The encoded optical signal is finally received by the total light intensity detector 5, and this received signal is the total light intensity value D W (t) collected by the single-pixel measurement module after spatial light modulation encoding of the target to be measured. Its mathematical expression can be written as:

[0066] D W (t) = ∫∫ Ω O W (x, y)H W (x, y, t)dxdy (1)

[0067] Wherein, O W (x, y) is the light intensity distribution of the target to be measured in the cross-band imaging embodiment, and H W (x, y, t) is the t-th frame modulation mask loaded by the first spatial light modulator 5 (DMD1), and Ω is the illumination area.

[0068] The electrical feedback module, the composition of this module is included in Figure 2 As Figure 2As shown, this module consists of a signal processing unit 6 (in this embodiment, a current-voltage conversion amplifier with model number YK-IV120K100 is selected) and a second light source 7 (in this embodiment, a white light LED with model number F5 white light and a color temperature of 6500 - 8000K is selected).

[0069] The total light intensity value D W (t) output from the single-pixel measurement module is fed to the signal processing unit 6 in the electrical feedback module via a circuit connection line, and D W (t) is converted into a driving signal V W (t), and they satisfy a certain functional relationship. In this embodiment, taking the linear functional relationship V W (t) = kD W (t) as an example, where k is a constant calibration coefficient. Then, V W (t) is further transmitted to the second light source 7 to drive its output light intensity I W (t), satisfying I W (t) ∝ V W (t) (also taking the linear functional relationship as an example), and further satisfying I W (t) ∝ V W (t) ∝ D W (t). In the cross-band correlation imaging embodiment, the light intensity signal used for optical correlation demodulation in the optical computing intensity correlation module and the total light intensity signal collected in the single-pixel measurement module have equivalent effects when using the same modulation mask.

[0070] Optical computing intensity correlation module, the composition of this module is included in Figure 2 . As Figure 2 shown, this module consists of a second spatial light modulator 8 (in this embodiment, a digital micromirror device is also selected as the second spatial light modulator, denoted as DMD2, with model number ViALUXV - 700), an array detector 9 (in this embodiment, a high-dynamic range CCD camera with model number ASI2600MC) and an image post-processing sub-module 10. It should be noted that the first spatial light modulator 4 (DMD1) and the second spatial light modulator 8 (DMD2) are synchronously loaded with the same modulation mask, and this synchronization process is completed by the synchronization control unit 12. And in this embodiment, the synchronization control unit is used to generate dual-channel synchronization signals to drive DMD1 and DMD2 respectively.

[0071] The illumination light output from the electrical feedback module irradiates the second spatial light modulator 8 (DMD2) to achieve spatial light modulation encoding. Then, this encoded optical signal is reflected into the array detector 9. In this embodiment, the integration time is set to 50 ms to achieve optical computing intensity correlation decoding. This process can be expressed as:

[0072]

[0073] Among them, I W (x, y, t) is the illumination light output by the electrical feedback module, and H W (x, y, t) is the modulation mask loaded on the second spatial light modulator 8 (DMD2) in a certain frame. At the same time, considering I W (t) ∝ V W (t) ∝ D W (t) and Equation (1), then there is:

[0074]

[0075] Among them, is the autocorrelation of the modulation mask. The entire correlation imaging autocorrelation process above can be completed through the integration of the array detector 9, that is, the image O can be directly decoded through optical computing intensity correlation (x, y). Finally, the decoded image is input into the image post-processing sub-module 10. W (x, y). Finally, the decoded image is input into the image post-processing sub-module 10.

[0076] The schematic diagram of the image post-processing process in the cross-band correlation imaging method based on optical computing provided by the embodiment of the present invention is as follows Figure 3 shown. In this embodiment, in the post-processing sub-module, the process S301 is first performed, that is, the gray value of the 32×32 pixel image output by the array detector 9 is normalized (dynamic range 0-255). Then, the process S302 is performed, and the background noise is filtered by applying digital band-pass filtering (cut-off frequency is 0.1-0.5 times the Nyquist frequency). Finally, the process S303 is performed, and the edge enhancement algorithm (such as the Sobel operator) is applied to enhance the clarity of the target details. After being processed by the image post-processing sub-module 10, the final imaging image 11 is output.

[0077] The present invention can be used not only for the above-mentioned cross-band imaging across bands, but also for cross-band imaging across light intensities. In order to have a deeper understanding of the present invention, another embodiment of the present invention - the cross-light intensity correlation imaging system and method based on optical computing will be described in detail below.

[0078] The overall flow schematic diagram of the cross-light intensity correlation imaging method based on optical computing provided by the described invention example is also as follows Figure 1 shown. The overall structure diagram of the cross-light intensity correlation imaging system based on optical computing provided by the above embodiment is as follows Figure 4 shown, and its difference from Figure 2 is that the total light intensity detector is replaced, and the first spatial light modulator and the second spatial light modulator are multiplexed, that is, only one spatial light modulator is required, and other devices remain unchanged. Below, each module in the above process will be described in more detail in combination with Figure 4 the above.

[0079] Single-pixel measurement module, which consists of components included in Figure 4 . As Figure 4 shown, this module is composed of a first light source 1-1 (in this embodiment, a halogen lamp is also selected as the first light source, model SLS202L, with a light-emitting band of 450-5500 nm, a peak wavelength of 1500 nm, and a light-emitting power of 7.2 W), a first spatial light modulator 2-1 (in this embodiment, a digital micromirror device is also selected as the spatial light modulator, denoted as DMD, model DLP9500), an attenuation medium 3-1 (in this embodiment, a neutral density filter, i.e., an attenuation sheet, is selected as the attenuation medium to attenuate the illumination light to create a low-light illumination environment), a target to be measured 4-1, and a total light intensity detector 5-1 (in this embodiment, a photomultiplier tube (PMT), model H10682).

[0080] Generate a Hadamard matrix of N orders (taking N = 1024 as an example) through a computer (which is also an example and is not limited to this Hadamard matrix). Each row of it is called a basis. Optimize the sorting of the bases, and then recombine each basis into a modulation mask of 32×32 pixels (the product is N). Obtain 1024 modulation masks for spatially light modulating and encoding the target to be measured.

[0081] After generating a preset number of modulation masks, display the above modulation masks through the first spatial light modulator 2-1 at a frequency of 22 kHz. Then use the first light source 1-1 to generate illumination light. The light beam irradiates the spatial light modulator 2-1 to form structured illumination light. The structured illumination light passes through the attenuation medium 3-1 to simulate a low-light extreme environment. Then the low-illumination light irradiates the target to be measured 4-1. The low light of the target to be measured 4-1 is received by the total light intensity detector 5-1. The received signal is the total light intensity value D I (t) collected by the single-pixel measurement module for the target to be measured after spatial light modulation encoding. Its mathematical expression can be written as:

[0082] D I (t) = ∫∫ Ω' O I (x,y)H I (x,y,t)dxdy (4)

[0083] where O I (x,y) is the light intensity distribution of the target to be imaged in the cross-light intensity imaging embodiment, and H I (x,y,t) is the structured illumination light generated after the illumination light irradiates the spatial light modulator 2-1, and Ω′ is the light modulation area.

[0084] Electrical feedback module, which consists of components included in Figure 4 . As Figure 4As shown, this module consists of a signal processing unit 6-1 (in this embodiment, a current-voltage conversion amplifier with model YK-IV120K100 is selected), and a second light source 1-1 (the second light source in this embodiment is multiplexed with the first light source).

[0085] The total light intensity value D I (t) output from the single-pixel measurement module is fed to the signal processing unit 8-1 in the electrical feedback module via a circuit connection line, and D I (t) is converted into a driving signal V I (t), and they satisfy a certain functional relationship. In this embodiment, taking the linear functional relationship V I (t) = kD I (t) as an example, where k is a constant calibration coefficient. Then, V I (t) is further transmitted to the second light source 1, enabling it to output illumination light I I (t), satisfying I I (t) ∝ V I (t) (also taking the linear functional relationship as an example), and further satisfying I I (t) ∝ V I (t) ∝ D I (t). Then, in the cross-intensity correlation imaging embodiment, the light intensity signal used for optical correlation demodulation and the total light intensity signal collected in the single-pixel measurement module have equivalent effects when using the same modulation mask.

[0086] An optical computing intensity correlation module, the composition of this module is included in Figure 4 . As Figure 4 shown, this module consists of a second spatial light modulator 2-1 (in this embodiment, the first and second spatial light modulators are multiplexed, that is, the second spatial light modulator is the same as the first spatial light modulator), an array detector 7-1 (in this embodiment, a high-dynamic range CCD camera with model FLIR-BFS-U3-16S2C-CS is selected), and an image post-processing sub-module 8-1.

[0087] The illumination light output from the electrical feedback module irradiates the second spatial light modulator 2-1 displaying the modulation mask, and the optical signal is reflected into the array detector 7-1 (in this embodiment, its integration time is set to 50 ms) to achieve optical computing intensity correlation decoding of the image. This process can be expressed as:

[0088]

[0089] Among them, I I (x, y, t) is the illumination light output from the electrical feedback module, H I(x, y, t) is a certain modulation mask loaded by the second spatial light modulator 2-1. Similar to the cross-band imaging embodiment, considering I I (t) ∝ V I (t) ∝ D I (t) and Equation (4), then we have:

[0090]

[0091] Among them, is the autocorrelation of the modulation mask. The entire correlation imaging autocorrelation process above is completed through the integration of the array detector 7-1, that is, the optical calculation intensity correlation directly decodes the image O I (x, y). Finally, the decoded image is input into the image post-processing sub-module 8-1.

[0092] The schematic diagram of the image post-processing process in the cross-band correlation imaging method based on optical calculation of the image post-processing sub-module 8-1 is also as Figure 3 shown. The image post-processing process is the same as that of the cross-band correlation imaging embodiment, that is, first perform the S301 process, normalize the gray value of the 32×32 pixel image output by the array detector 7-1 (taking the dynamic range of 0 to 255 as an example), then perform the S302 process, apply digital band-pass filtering (cutoff frequency is 0.1 to 0.5 times the Nyquist frequency) to filter out background noise, and finally perform the S303 process, apply an edge enhancement algorithm (such as the Sobel operator) to enhance the clarity of target details. After being processed by the image post-processing sub-module 8-1, the final imaging image 9-1 is output.

[0093] It should be noted that in the cross-band correlation imaging system and method based on optical calculation, regardless of whether the cross-band or cross-intensity imaging scheme is adopted, and whether the spatial light modulation coding of the single-pixel measurement module is implemented before or after the object, the effect is the same.

[0094] In summary, the embodiments of the present application have the following beneficial effects:

[0095] By fusing the signal modulation ability and correlation demodulation characteristics of the correlation imaging technology, combining the electrical feedback and optical calculation intensity correlation decoding technology, the correlation imaging can perform cross-band imaging on the target to be measured in complex scenarios (such as extremely weak light, strong scattering, imaging band in the non-visible light band, etc.).

[0096] Specifically, on the one hand, the embodiments of the present application use optical computing to achieve device intensity correlation decoding, breaking the convention that traditional correlation imaging technology requires computer-based image post-processing reconstruction. Instead, it directly realizes intensity correlation through the integration process of an array detector. The integrated image recorded by the array detector is the image of the object to be measured obtained by cross-band optical computing intensity correlation decoding, enabling cross-band imaging of the object to be measured in the above complex scenarios. In addition, through the use of a cleverly structured modulation mask construction, the contribution of the modulation mask to image reconstruction is enhanced, thereby enhancing the quality of the reconstructed image. That is, the technical solution corresponding to the embodiments of the present application greatly increases the imaging performance while ensuring the quality of image reconstruction, and at the same time, the embodiments of the present application have almost zero computational burden and imaging bandwidth limitations.

[0097] On the other hand, the embodiments of the present application use electrical feedback technology to enable correlation imaging to obtain compatibility with various complex scenarios. Specifically, the total optical intensity signal function after spatial light modulation encoding collected is converted into illumination light of corresponding intensity for subsequent cross-band optical computing intensity correlation decoding. This makes the correlation imaging system designed based on this scheme no longer only applicable to a specific situation (such as a specific wavelength band range or a specific light intensity level, etc.), but can achieve cross-band (here, cross-band means crossing a certain physical quantity range) correlation imaging such as cross-bandwidth and cross-light intensity. It no longer needs to rely on multiple independent systems to achieve this function, thereby greatly reducing hardware redundancy and detection costs, and also greatly enhancing the application flexibility of correlation imaging, enabling it to flexibly cope with various complex, changeable, and even extreme imaging environments.

[0098] In several embodiments provided by the present application, it should be understood that the disclosed methods and electronic devices can be implemented in other ways. The device embodiments described above are only illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined, or integrated into another system, or some features can be ignored, or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed may be through some interfaces. The indirect coupling or communication connection of devices or units can be electrical, mechanical, or other forms.

[0099] The modules described as separate components may or may not be physically separated. The components shown as modules may or may not be physical units, that is, they may be located in one place, or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0100] In addition, in each embodiment of the present application, each functional unit may be integrated into one processing unit, may exist physically alone for each unit, or two or more units may be integrated into one unit.

[0101] If the above-mentioned function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium executable by a processor. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a platform server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical discs that can store program codes.

[0102] The above are only the specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A cross-band correlation imaging system based on optical computing, characterized in that The system includes: a single-pixel measurement module, an electrical feedback module, and an optical computing intensity correlation module; The single-pixel measurement module includes a first light source, a first spatial light modulator, and a total light intensity detector. The first light source is used to irradiate the target to be measured. The first spatial light modulator is used to perform spatial light modulation encoding on the target to be measured. The total light intensity detector is used to measure the total light intensity value of the target to be measured after spatial light modulation encoding; The electrical feedback module includes a signal processing unit and a second light source. The signal processing unit is used to perform analog-to-digital conversion, signal amplification, and specific function operations on the analog signal output by the total light intensity detector. The second light source is used to generate illumination light whose emission intensity has a specific functional relationship with the captured total light intensity value according to the drive signal output by the signal processing unit; The optical computing intensity correlation module includes a second spatial light modulator and an array detector. The second spatial light modulator is used to modulate the illumination light output by the second light source. The array detector is used to decode and reconstruct the cross-band image of the target to be measured by integrating the light wave intensity distribution modulated by the second spatial light modulator; 2. The system according to claim 1, wherein The cross-band correlation imaging characterization can perform correlation imaging across the range of physical quantities. Whether the spatial light modulation encoding of the single-pixel measurement module is implemented before or after the object to be measured does not affect the correlation imaging result; The physical quantities include, but are not limited to, the wavelength of light and the intensity of light; When implementing cross-band optical computing correlation imaging, cross-band optical computing correlation imaging is achieved by selecting the first light source, the second light source, the total light intensity detector, and the array detector with different wavelength ranges; When implementing cross-light-intensity optical computing correlation imaging, cross-light-intensity optical computing correlation imaging is achieved by selecting the first light source and the second light source with different powers or light fluxes, and the total light intensity detector and the array detector with different detection sensitivities; 3. The system according to claim 1, wherein The modulation masks loaded by the first spatial light modulator and the second spatial light modulator are masks capable of realizing spatial light modulation. The modulation masks include, but are not limited to, Hadamard basis modulation masks, Vandermonde matrix basis modulation masks, Fourier basis modulation masks, discrete cosine basis modulation masks, Gaussian / sub-Gaussian distribution basis modulation masks, Poisson / sub-Poisson distribution basis modulation masks, random matrix basis modulation masks, Toeplitz matrix basis modulation masks, Hankel matrix basis modulation masks, orthogonal basis modulation masks, sparse basis modulation masks; 4. The system according to claim 1, characterized in that When the modulated lights in the single-pixel measurement module and the optical computing intensity correlation module do not interfere with each other, the first light source and the second light source share the same one, and the first spatial light modulator and the second spatial light modulator share the same one; If the first spatial light modulator and the second spatial light modulator are not the same one, the first spatial light modulator and the second spatial light modulator control the timing error within the tolerance range by connecting to a synchronization control unit; 5. The system according to claim 1, characterized in that, The total light intensity detector includes a point detector or a bucket detector; The integration time of the array detector is adjusted as needed; 6. A cross-band correlation imaging method based on optical computing, characterized in that, The method includes: Irradiate the target to be measured with a first light source, construct a modulation matrix, generate a preset number of modulation masks, and load the generated modulation masks onto a first spatial light modulator, so that the first spatial light modulator displays the modulation masks at a preset switching frequency, and synchronously capture the total light intensity value through a total light intensity detector; Input the total light intensity value into a signal processing unit for analog-to-digital conversion, signal amplification, and specific function operations to obtain a drive signal, and input the drive signal into a second light source, so that the second light source generates illumination light whose emission intensity has a specific functional relationship with the captured total light intensity value; Irradiate the illumination light output by the second light source onto a second spatial light modulator to achieve spatial light modulation encoding, collect the light field modulated and encoded by the second spatial light modulator through an array detector with a preset integration time, and determine the integrated image recorded by the array detector as the object image obtained by cross-band light calculation intensity correlation decoding; wherein, the second spatial light modulator and the first spatial light modulator load the modulation masks with the same sequence, and the integration process of the integrated image is used to achieve cross-band light calculation intensity correlation; Perform post-processing on the object image to improve the image quality; the post-processing includes but is not limited to using relevant algorithms or filters.

7. The method according to claim 6, wherein The cross-band correlation imaging characterization can perform correlation imaging across the range of physical quantities, and the spatial light modulation encoding of the single-pixel measurement module involved does not affect the correlation imaging result whether it is implemented before or after the object to be measured; the physical quantities include but are not limited to the wavelength and intensity of light; When implementing cross-band light calculation correlation imaging, cross-band light calculation correlation imaging is achieved by selecting the first light source and the second light source, the total light intensity detector and the array detector with different wavelength ranges; When implementing cross-light intensity light calculation correlation imaging, cross-light intensity light calculation correlation imaging is achieved by selecting the first light source and the second light source with different powers or light fluxes, and the total light intensity detector and the array detector with different detection sensitivities; The cross-band light calculation correlation imaging characterization means that the signal acquisition of the single-pixel measurement module and the integral decoding process of the light calculation intensity correlation module are respectively implemented in different wavelength bands, including non-visible band to visible band or non-array measurable band to array measurable band; The cross-light intensity light calculation correlation imaging characterization means that the signal acquisition of the single-pixel measurement module and the integral decoding process of the light calculation intensity correlation module are respectively implemented at different light intensities, including weak light, single-photon target signal to strong light array detection.

8. The method according to claim 6, wherein The modulation masks loaded by the first spatial light modulator and the second spatial light modulator are masks capable of realizing spatial light modulation, and the modulation masks include but are not limited to one of Hadamard basis modulation masks, Vandermonde matrix basis modulation masks, Fourier basis modulation masks, discrete cosine basis modulation masks, Gaussian / sub-Gaussian distribution basis modulation masks, Poisson / sub-Poisson distribution basis modulation masks, random matrix basis modulation masks, Toeplitz matrix basis modulation masks, Hankel matrix basis modulation masks, orthogonal basis modulation masks, sparse basis modulation masks.

9. The method according to claim 6, wherein The electrical feedback module further includes, but is not limited to, screening the total light intensity value by using the consistency imaging mechanism in correlated imaging, and then performing modulation mask gating on the modulation mask sequence loaded by the second spatial light modulator. Alternatively, the driving signal and the total light intensity value satisfy a specific functional relationship through an objective function, and the objective function includes, but is not limited to, one of a high-order type, an exponential type, a logarithmic type, a triangular type, and a differential type.

10. The method according to claim 6, wherein The electrical feedback module and the second light source need to be calibrated, including but not limited to the following methods: Using a standard target object, fitting and correcting the total light intensity value output by the single-pixel measurement module and the illumination light output by the electrical feedback module.

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