Spectral calibration methods and systems, data measurement methods and systems, equipment and media

Abstract

This application discloses a spectral calibration method and system, a data measurement method and system, equipment, and a medium, belonging to the technical field of optical instrument technology. The spectral calibration method includes: setting the current bias current value of an SNSPI imager; setting the energy value of a laser to ensure that the photon output rate of the laser to the SNSPI imager reaches a preset value; sequentially emitting laser light into the SNSPI imager according to each wavelength of the spectral data to be calibrated, obtaining the electrical pulse time difference of the pixels in the SNSPI imager, and calculating the photon responsivity of the pixels to each wavelength of the spectral data to be calibrated based on the electrical pulse time difference; constructing the spectral response matrix of the SNSPI imager based on the photon responsivity, thus completing the spectral calibration. This application can obtain a spectral response matrix with a low condition number through spectral calibration, improving measurement accuracy.

Description

Technical Field

[0001] This application relates to the field of optical instrument technology, and in particular to a spectral calibration method and system, a data measurement method and system, equipment and medium. Background Technology

[0002] Spectroscopic measurement technology is a method for analyzing substances by measuring the interaction between substances and electromagnetic radiation to obtain relevant information about the substances.

[0003] In related technologies, the spectral response characteristics of a spectral detector are typically used to acquire the spectral data to be measured. These spectral response characteristics can be represented by a spectral response matrix. However, this matrix has a large number of condition numbers, leading to significant errors in the spectral data calculated using the spectral detector.

[0004] Therefore, how to obtain a spectral response matrix with a low condition number through spectral calibration and improve measurement accuracy is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to provide a spectral calibration method, a spectral calibration system, a spectral data measurement method, a spectral data measurement system, an electronic device, and a storage medium, which can obtain a spectral response matrix with a low condition number through spectral calibration, thereby improving measurement accuracy.

[0006] To address the aforementioned technical problems, this application provides a spectral calibration method, comprising:

[0007] Set the current bias current value of the SNSPI imager;

[0008] Set the energy value of the laser so that the photon output rate of the laser to the SNSPI imager reaches a preset value;

[0009] The laser is used to sequentially emit laser light into the SNSPI imager according to each wavelength of the spectral data to be calibrated, thereby obtaining the electrical pulse time difference of the pixels in the SNSPI imager, and calculating the photon responsivity of the pixel to each wavelength of the spectral data to be calibrated based on the electrical pulse time difference; wherein, the electrical pulse time difference is the time difference between the electrical pulse generated after the pixel absorbs a photon and the two ends of the SNSPI imager where the pixel is located.

[0010] The spectral response matrix of the SNSPI imager is constructed based on the photon responsivity to complete the spectral calibration.

[0011] Optionally, setting the current bias current value of the SNSPI imager includes:

[0012] Determine the wavelength range for all spectral data to be calibrated;

[0013] Set the midpoint value of the wavelength range as the target wavelength;

[0014] The laser is used to emit a laser of the target wavelength toward the SNSPI imager;

[0015] Increase the bias current of the SNSPI imager and record the photon output rate of the SNSPI imager;

[0016] Determine the saturated photon output rate when the photon output rate of the SNSPI imager reaches saturation.

[0017] Set the bias current value corresponding to the saturated photon output rate as the saturated current value;

[0018] The current bias current value of the SNSPI imager is set according to the saturation current value.

[0019] Optionally, setting the current bias current value of the SNSPI imager based on the saturation current value includes:

[0020] The bias current value corresponding to the half-saturated photon output rate is set as the half-saturated current value; wherein, the half-saturated photon output rate is half of the saturated photon output rate;

[0021] Construct a range of candidate current values ​​with an upper bound of the saturation current value and a lower bound of the half-saturation current value;

[0022] Multiple alternative current values ​​are selected from the range of alternative current values, and the alternative current values ​​are set as the current bias current values ​​of the SNSPI imager.

[0023] Optionally, constructing the spectral response matrix of the SNSPI imager based on the photon responsivity includes:

[0024] Generate a spectral response submatrix based on the photon responsivity of the pixel to each wavelength at each current bias current value;

[0025] The spectral response matrix of the SNSPI imager is constructed based on all the spectral response sub-matrices.

[0026] Optionally, setting the energy value of the laser to achieve a preset photon output rate for the SNSPI imager includes:

[0027] Select the test wavelength from the wavelengths of the spectral data to be calibrated;

[0028] The laser is controlled to emit laser light toward the beam splitter according to the test wavelength, so that the beam splitter illuminates the optical power meter and the SNSPI imager with the laser light according to a preset ratio;

[0029] The current photon output rate of the laser to the SNSPI imager is calculated based on the power value detected by the optical power meter and the preset ratio.

[0030] The energy value of the laser is adjusted according to the current photon output rate of the laser to the SNSPI imager, so that the photon output rate of the laser to the SNSPI imager reaches the preset value.

[0031] Optionally, the laser is used to sequentially emit laser light into the SNSPI imager according to each wavelength of the spectral data to be calibrated, to obtain the electrical pulse time difference of the pixels in the SNSPI imager, and the photon responsivity of the pixel to each wavelength of the spectral data to be calibrated is calculated based on the electrical pulse time difference, including:

[0032] Select the current calibration wavelength from the wavelengths of the spectral data to be calibrated;

[0033] The laser is used to sequentially emit lasers at the SNSPI imager according to the current calibration wavelength to obtain the electrical pulse time difference of the pixels in the SNSPI imager;

[0034] Calculate the photon responsivity of the pixel to the current calibration wavelength based on the electrical pulse time difference;

[0035] Determine whether all wavelengths of the spectral data to be calibrated have been selected;

[0036] If not, proceed to the step of selecting the current calibration wavelength from the wavelengths of the spectral data to be calibrated.

[0037] Optionally, calculating the photon responsivity of the pixel to the current calibration wavelength based on the electrical pulse time difference includes:

[0038] Generate statistical histograms corresponding to all the time differences of the electrical pulses;

[0039] Identify n statistical peaks in the statistical histogram; wherein, each statistical peak corresponds one-to-one with a pixel;

[0040] The ratio of the number of electrical pulse time differences contained in each statistical peak to the total number of photons is used as the photon responsivity of the corresponding pixel to the current calibrated wavelength.

[0041] Optionally, before calculating the photon responsivity of the pixel to each wavelength in the spectral data to be calibrated based on the electrical pulse time difference, the method further includes:

[0042] Pixels in the SNSPI imager that meet preset conditions are set as target pixels; wherein, the preset conditions are: the composite degree (i.e., correlation coefficient) of the spectral response curve of the target pixel with the spectral response curve of other pixels is lower than a preset value.

[0043] Accordingly, calculating the photon responsivity of the pixel to each wavelength in the spectral data to be calibrated based on the electrical pulse time difference includes:

[0044] The photon responsivity of the target pixel to each wavelength in the spectral data to be calibrated is calculated based on the time difference of the electrical pulse.

[0045] This application also provides a spectral calibration system, the system comprising:

[0046] The bias current setting module is used to set the current bias current value of the SNSPI imager;

[0047] A laser setting module is used to set the energy value of the laser so that the photon output rate of the laser to the SNSPI imager reaches a preset value.

[0048] The responsivity calculation module is used to sequentially emit laser light to the SNSPI imager according to each wavelength of the spectral data to be calibrated using the laser, obtain the electrical pulse time difference of the pixels in the SNSPI imager, and calculate the photon responsivity of the pixel to each wavelength of the spectral data to be calibrated based on the electrical pulse time difference; wherein, the electrical pulse time difference is the time difference between the electrical pulse generated after the pixel absorbs a photon and the two ends of the SNSPI imager where the pixel is located.

[0049] The matrix construction module is used to construct the spectral response matrix of the SNSPI imager based on the photon responsivity, thereby completing the spectral calibration.

[0050] This application also provides a method for measuring spectral data, the method comprising:

[0051] Receive spectral data measurement tasks;

[0052] The polychromatic light to be measured corresponding to the spectral data measurement task is irradiated onto the SNSPI imager to obtain the observation data;

[0053] The observed data are converted into corresponding spectral data using the spectral response matrix;

[0054] The SNSPI imager and the spectral response matrix are the SNSPI imager and spectral response matrix in the above-mentioned spectral calibration method.

[0055] This application also provides a spectral data measurement system, the system comprising:

[0056] The task receiving module is used to receive spectral data measurement tasks;

[0057] The measurement module is used to illuminate the polychromatic light to be measured corresponding to the spectral data measurement task onto the SNSPI imager to obtain observation data;

[0058] A conversion module is used to convert the observed data into corresponding spectral data using the spectral response matrix;

[0059] Wherein, the SNSPI imager and the spectral response matrix are the SNSPI imager and spectral response matrix in the spectral calibration method described above.

[0060] This application also provides a storage medium storing a computer program thereon, which, when executed, implements the steps of the above-described spectral calibration method and / or the steps of the above-described spectral data measurement method.

[0061] This application also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program, and the processor invokes the computer program in the memory to implement the steps of the above-described spectral calibration method and / or the steps of the above-described spectral data measurement method.

[0062] This application provides a spectral calibration method, comprising: setting the current bias current value of an SNSPI imager; setting the energy value of a laser to make the photon output rate of the laser to the SNSPI imager reach a preset value; using the laser to sequentially emit laser light to the SNSPI imager according to each wavelength of the spectral data to be calibrated, obtaining the electrical pulse time difference of the pixels in the SNSPI imager, and calculating the photon responsivity of the pixel to each wavelength in the spectral data to be calibrated based on the electrical pulse time difference; wherein, the electrical pulse time difference is the time difference between the electrical pulse generated after the pixel absorbs a photon and the two ends of the SNSPI imager where the pixel is located; constructing the spectral response matrix of the SNSPI imager based on the photon responsivity to complete the spectral calibration.

[0063] This application sets the current bias current value of the SNSPI imager and the energy value of the laser, and sequentially emits laser light to the SNSPI imager according to each wavelength of the spectral data to be calibrated, so as to measure the spectral data using an SNSPI imager comprising multiple pixels. After a pixel of the SNSPI imager absorbs a photon, it generates an electrical pulse. This application calculates the photon responsivity of each pixel to each wavelength based on the time difference between the electrical pulses arriving at the two ends of the superconducting nanowire single-photon imager where the pixel is located. Based on the photon responsivity, the spectral response matrix of the SNSPI imager can be constructed, thereby realizing the spectral calibration of the SNSPI imager. The above method can achieve the spectral calibration of the spectral imager, reduce the condition number of the spectral response matrix, and improve the measurement accuracy. This application also provides a spectral calibration method system, a spectral data measurement method, a spectral data measurement system, an electronic device, and a storage medium, which have the above-mentioned beneficial effects, and will not be elaborated further here. Attached Figure Description

[0064] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0065] Figure 1 A flowchart of a spectral calibration method provided in an embodiment of this application;

[0066] Figure 2 This is a schematic diagram of the structure of the first SNSPI imager provided in the embodiments of this application;

[0067] Figure 3 This is a schematic diagram of the structure of the second SNSPI imager provided in the embodiments of this application;

[0068] Figure 4 This is a schematic diagram of an SNSPI imager generating electrical pulses provided in an embodiment of this application;

[0069] Figure 5 A statistical histogram of electrical pulse time difference provided in an embodiment of this application;

[0070] Figure 6 This is a schematic diagram of an SNSPI spectral response matrix calibration process provided in an embodiment of this application;

[0071] Figure 7 This is a schematic diagram of an SNSPI spectral observation data and calculation process provided in an embodiment of this application;

[0072] Figure 8 A schematic diagram showing the comparison of the spectral response matrix of an existing solution in the art with that of this application, provided as an embodiment of this application;

[0073] Figure 9 This is a schematic diagram of the structure of a spectral calibration system provided in an embodiment of this application;

[0074] Figure 10 This is a schematic diagram of the structure of a spectral data measurement system provided in an embodiment of this application. Detailed Implementation

[0075] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0076] Please see below. Figure 1 , Figure 1 This is a flowchart of a spectral calibration method provided in an embodiment of this application.

[0077] Specific steps may include:

[0078] S101: Sets the current bias current value of the SNSPI imager;

[0079] This embodiment can be applied to optical devices including an SNSPI imager (Superconducting Nanowire Single-Photon Imager) and a laser, thereby performing spectral calibration on the SNSPI imager so as to acquire spectral data using the spectrally calibrated SNSPI imager. The SNSPI imager includes multiple pixels.

[0080] Please see Figure 2 , Figure 2 This is a schematic diagram of the structure of the first SNSPI imager provided in the embodiments of this application. Figure 2 The SNSPI imager shown is a planar detector formed by the meandering delay lines fabricated from a single superconducting nanowire; please refer to [link to relevant documentation]. Figure 3 , Figure 3 This is a schematic diagram of the structure of the second SNSPI imager provided in the embodiments of this application. Figure 3 The SNSPI imager shown is a surface array detector formed by the meandering delay lines made of multiple superconducting nanowires.

[0081] SNSPI imagers are area photodetectors formed by meandering delay lines fabricated from single superconducting nanowires. SNSPI imagers have hundreds or thousands of detector pixels. Figure 2 and Figure 3 Each of the small black squares in the image. Typically, SNSPI imagers are used only as detectors for area array imaging; however, SNSPI imagers also have the potential to perform computational spectral measurements, and there is currently no scheme in the art for using SNSPI imagers to perform computational spectral data measurements.

[0082] This embodiment uses spectral data to be calibrated to calibrate the SNSPI imager in order to obtain a spectral response matrix. The spectral data to be calibrated can include spectral data of various known wavelengths. In this embodiment, laser light is irradiated onto the SNSPI imager according to the wavelength of the spectral data to be calibrated, the bias current of the SNSPI imager is adjusted, and then the current bias current value of the SNSPI imager is set according to the relationship between the photon output rate of the SNSPI imager and the bias current.

[0083] S102: Set the energy value of the laser so that the photon output rate of the laser to the SNSPI imager reaches a preset value;

[0084] In this embodiment, the desired photon output rate of the SNSPI imager can be preset, i.e., a preset value. By changing the energy value of the laser when it is working, the photon output rate of the laser to the SNSPI imager can reach the preset value.

[0085] S103: Using the laser, lasers are emitted sequentially at each wavelength of the spectral data to be calibrated to the SNSPI imager to obtain the electrical pulse time difference of the pixels in the SNSPI imager, and the photon responsivity of the pixel to each wavelength in the spectral data to be calibrated is calculated based on the electrical pulse time difference.

[0086] In this embodiment, the current spectral data to be calibrated can be selected from the spectral data to be calibrated. Laser light is emitted into the SNSPI imager according to the wavelength of the current spectral data to be calibrated, and the electrical pulse time difference of the pixel is obtained. This electrical pulse time difference is the time difference between the two ends of the SNSPI imager where the pixel is located after the pixel absorbs photons (photons of the laser light at the wavelength of the current spectral data to be calibrated), specifically the time difference between the left and right ends of the SNSPI imager where the pixel is located. The photon responsivity of the pixel to the wavelength of the current spectral data to be calibrated is calculated based on the electrical pulse time difference.

[0087] After obtaining the photon responsivity corresponding to the current spectral data to be calibrated, this step can select new current spectral data to be calibrated in order to generate the photon responsivity of the pixel for each wavelength in the spectral data to be calibrated.

[0088] As one feasible implementation, this embodiment can calculate the photon responsivity of all pixels in the SNSPI imager for each wavelength in the spectral data to be calibrated based on the electrical pulse time difference. As another feasible implementation, this embodiment can set a target pixel in the SNSPI imager that meets a preset condition; the target pixel is a pixel with relatively good control data. The preset condition is that the composite degree (i.e., correlation coefficient) of the spectral response curve of the target pixel with the spectral response curves of other pixels is lower than a preset value. After determining the target pixel, the photon responsivity of the target pixel for each wavelength in the spectral data to be calibrated can be calculated based on the electrical pulse time difference.

[0089] S104: Construct the spectral response matrix of the SNSPI imager based on the photon responsivity to complete the spectral calibration.

[0090] In this embodiment, after establishing the spectral response matrix of the SNSPI imager, it indicates that the spectral calibration operation of the SNSPI imager has been completed. During subsequent acquisition of spectral data using the SNSPI imager, the spectral response matrix obtained through the spectral calibration method provided in this embodiment can be used to convert the observed data into corresponding spectral data.

[0091] In this embodiment, the spectral response matrix Φ of the SNSPI imager can be constructed from the photon responsivity of n pixels to m wavelengths as follows:

[0092]

[0093] Element φ in the spectral response matrix ij Let represent the photon responsivity of the i-th pixel to the j-th wavelength, 1≤i≤n, 1≤j≤m. The above process provides a scheme for spectral response modulation of each pixel in an SNSPI imager. This scheme treats the n pixels of the SNSPI imager as n different spectral response modulation methods. Using a single bias current, the SNSPI is illuminated successively with m wavelengths to be calibrated, and the spectral responsivity of the n pixels of the SNSPI to each wavelength is measured. Finally, an n x m spectral response matrix is ​​obtained, which can be used to calculate spectral measurements.

[0094] Specifically, in this embodiment, a spectral response sub-matrix can be generated based on the photon responsivity of the pixel to each wavelength under each current bias current value; and the spectral response matrix of the SNSPI imager can be constructed based on all the spectral response sub-matrixes. This embodiment can select the current bias current value from a range of candidate current values, and then generate a spectral response sub-matrix based on the photon responsivity of the pixel to each wavelength in the spectral data to be calibrated when the current bias current value of the SNSPI imager is each candidate current value; and construct the spectral response matrix of the SNSPI imager based on the spectral response sub-matrixes corresponding to all the candidate current values.

[0095] This embodiment allows setting multiple current bias current values ​​for the SNSPI imager, thereby obtaining the photon responsivity of n pixels to m wavelengths under k current bias current values, and thus obtaining the following spectral response matrix Φ:

[0096]

[0097] Element Φ in the spectral response matrix (g) This represents the spectral response submatrix for the g-th current bias current value, where 1 ≤ g ≤ k. The spectral response submatrix is ​​as follows: Φ (g) :

[0098]

[0099] Element φ in the spectral response submatrix ij This represents the photon responsivity of the i-th pixel to the j-th wavelength under the current bias current value.

[0100] The above process provides a scheme for richer spectral response modulation of each pixel and bias current of the SNSPI imager. K bias currents (k≥2) are selected. Under each bias current, the SNSPI imager is successively illuminated with m wavelengths to be calibrated. The spectral responsivity of the n pixels of the SNSPI imager to each wavelength is measured, resulting in an n x m sub-matrix of spectral response. The calibration of the n x m sub-matrixes under the k bias currents is then performed sequentially. Finally, the k spectral response sub-matrices are merged to obtain an nk x m sub-matrix with richer information content, Φ, for higher-quality computational spectral measurements.

[0101] The above process proposes a feasible scheme for using SNSPI to calculate spectral measurements. By treating the hundreds or thousands of pixels in the SNSPI imager as hundreds or thousands of spectral response modulation schemes, each pixel can respond to several different spectral data to be measured under each modulation scheme. In this way, each pixel of the SNSPI imager naturally possesses different spectral response characteristics, i.e., it has the ability to construct a spectral response matrix Φ. Furthermore, in this embodiment, when multiple bias currents are set for the SNSPI imager, each of the hundreds or thousands of pixels can further exhibit its own different spectral response characteristics under various bias currents, thus obtaining a very rich and diverse spectral response matrix.

[0102] This embodiment sets the current bias current value of the SNSPI imager and the energy value of the laser, and sequentially emits laser light to the SNSPI imager according to each wavelength of the spectral data to be calibrated, so as to measure the spectral data using an SNSPI imager comprising multiple pixels. After a pixel of the SNSPI imager absorbs a photon, it generates an electrical pulse. This embodiment calculates the photon responsivity of each pixel to each wavelength based on the time difference between the electrical pulses arriving at the two ends of the superconducting nanowire single-photon imager where the pixel is located. Based on the photon responsivity, the spectral response matrix of the SNSPI imager can be constructed, thereby realizing the spectral calibration of the SNSPI imager. The above method can achieve spectral calibration of the spectral imager, reduce the condition number of the spectral response matrix, and improve measurement accuracy.

[0103] As for Figure 1 In a further description of the corresponding embodiment, based on the obtained spectral response matrix of the SNSPI imager, the following spectral data measurement operations can be performed using the SNSPI imager and its spectral response matrix:

[0104] Step 1: Receive spectral data measurement task;

[0105] Step 2: Illuminate the polychromatic light to be measured corresponding to the spectral data measurement task onto the SNSPI imager to obtain observation data;

[0106] Step 3 uses the spectral response matrix to convert the observed data into corresponding spectral data.

[0107] Furthermore, after obtaining the spectral response matrix, it can be stored. Upon receiving a spectral data measurement task, it is unnecessary to repeat the operations described in S101 to S104. Instead, the pre-obtained spectral response matrix is ​​read to perform the operation of converting the observed data into spectral data.

[0108] Specifically, after receiving the spectral data measurement task, this embodiment can determine the polychromatic light to be measured corresponding to the spectral data measurement task, illuminate the polychromatic light to be measured onto the SNSPI imager to obtain observation data, and then use the calibrated spectral response matrix to convert the observation data into the corresponding spectral data.

[0109] After the polychromatic light to be measured is irradiated onto the SNSPI imager, under the action of the aforementioned spectral response matrix, the SNSPI imager can convert the spectral data x to be measured into observed data y. In this embodiment, x = Φ can be solved using the spectral response matrix Φ of the SNSPI. -1 The mathematical inverse problem of y is that the spectral data to be measured, x, can be recovered from the observed data y.

[0110] As a feasible implementation, when the polychromatic light to be measured is irradiated onto the SNSPI imager to obtain observation data y of an unknown spectrum, k ≥ 2 bias currents can be selected. Under each bias current, the number of electrical pulse time differences recorded by n pixels of the SNSPI imager is measured, and this result is taken as observation data y under a bias current. (k) The observation data under k bias currents are arranged sequentially to form the final nk rows of observation data y.

[0111] The spectral response matrix in this embodiment uses Figure 1 The corresponding embodiment is constructed such that, upon receiving a spectral data measurement task, an SNSPI imager is used to acquire observation data, and the spectral response matrix is ​​used to convert the observation data into corresponding spectral data. This embodiment utilizes an SNSPI imager to achieve spectral data detection, which can reduce the condition number of the spectral response matrix and improve the measurement accuracy of spectral data.

[0112] As for Figure 1 A further description of the corresponding embodiment is that the current bias current value of the SNSPI imager can be set in the following way: determine the wavelength range of all the spectral data to be calibrated; set the midpoint value of the wavelength range as the target wavelength; emit laser light of the target wavelength into the SNSPI imager using the laser; increase the bias current of the SNSPI imager and record the photon output rate of the SNSPI imager; determine the saturated photon output rate when the photon output rate of the SNSPI imager reaches saturation; set the bias current value corresponding to the saturated photon output rate as the saturated current value; and set the current bias current value of the SNSPI imager according to the saturated current value.

[0113] Specifically, in this embodiment, the half-saturated photon output rate can be determined, and the bias current value corresponding to the half-saturated photon output rate can be set as the half-saturated current value; wherein, the half-saturated photon output rate is half of the saturated photon output rate; a candidate current value range with an upper limit of the saturated current value and a lower limit of the half-saturated current value can be constructed; multiple candidate current values ​​can be selected from the candidate current value range, and the candidate current values ​​can be set as the current bias current value of the SNSPI imager.

[0114] As a feasible implementation method, this embodiment can configure the laser as follows: select a test wavelength from the wavelengths of the spectral data to be calibrated; control the laser to emit laser light towards the beam splitter according to the test wavelength, so that the beam splitter illuminates the optical power meter and the SNSPI imager with laser light according to a preset ratio; calculate the current photon output rate of the laser to the SNSPI imager based on the power value detected by the optical power meter and the preset ratio; adjust the energy value of the laser based on the current photon output rate of the laser to the SNSPI imager, so that the photon output rate of the laser to the SNSPI imager reaches the preset value.

[0115] As a feasible implementation method, Figure 1 A corresponding embodiment can calculate the photon responsivity of a pixel to each wavelength in the spectral data to be calibrated as follows: select the current calibration wavelength from the wavelengths of the spectral data to be calibrated; use the laser to sequentially emit laser light to the SNSPI imager according to the current calibration wavelength to obtain the electrical pulse time difference of the pixel; calculate the photon responsivity of the pixel to the current calibration wavelength based on the electrical pulse time difference; determine whether all wavelengths of the spectral data to be calibrated have been selected; if not, proceed to the step of selecting the current calibration wavelength from the wavelengths of the spectral data to be calibrated.

[0116] Specifically, in this embodiment, a statistical histogram can be used to calculate the photon responsivity of a pixel to the current calibration wavelength:

[0117] Generate statistical histograms corresponding to all the electrical pulse time differences; determine n statistical peaks in the statistical histograms; wherein each statistical peak corresponds one-to-one with a pixel; and use the ratio of the number of electrical pulse time differences contained in each statistical peak to the total number of photons as the photon responsivity of the corresponding pixel to the current calibration wavelength. The total number of photons is all photons irradiated by the SNSPI imager.

[0118] The process described in the above embodiments is illustrated below through examples in practical applications.

[0119] Computational spectral measurement is a novel spectral measurement technique that differs from traditional spectral measurement in its fundamental principles. This technique utilizes the spectral response characteristics of a spectral imager to compute the spectral data x = [x1, x2, ..., xm], where the number of spectral channels is m. m ] T Convert the observed data y = [y1, y2, ..., y] to a modulation order of n. n ] T In the computational spectral measurement process of converting x to y, the spectral response characteristics of the spectral imager play a crucial role. These characteristics can be represented by an n x m spectral response matrix Φ.

[0120]

[0121] At this point, the process of converting x to y through computational spectral measurement can be expressed as the mathematical formula y = Φx. Solving for x = Φ... -1 The mathematical inverse problem of y is that the spectral data to be measured, x, can be recovered from the observed data y.

[0122] Spectral response characteristics are a prerequisite for computational spectral measurements. Mathematically, the detector needs to possess n different spectral response modulation methods, with each row of the spectral response matrix Φ representing one modulation method. Under each modulation method, the detector must be able to respond to m different spectral data points, and any row of the spectral response matrix Φ must have the responsivity of m spectral data points. Only when the detector possesses n spectral response modulation methods, each with m spectral responsivity, and constructs an n x m spectral response matrix Φ, can computational spectral measurements be performed.

[0123] In existing computational spectroscopy techniques using superconducting nanowire detectors, the spectral response matrix is ​​typically highly ill-conditioned, which is detrimental to spectral reconstruction. Mathematically, the greater the ill-conditioning of the matrix Φ, the more difficult it is to solve for x = Φ. -1 The larger the error in the mathematical inverse of y, the better. The ill-conditioned nature of a matrix can be measured by its condition number. For a well-conditioned x = Φ -1 The mathematical inverse of y has a condition number of matrix Φ equal to 1. However, in existing computational spectroscopy techniques using superconducting nanowire detectors, the condition number of the spectral response matrix is ​​typically in the range of 10. 4 ~10 7 Between. A huge condition number will lead to problems in solving x = Φ. -1 The mathematical inverse of y introduces significant errors. Currently, the hundreds or thousands of pixels in SNSPI imagers are typically used for area imaging, such as active 3D imaging and passive scene imaging. There is currently no feasible way to utilize the hundreds or thousands of pixels in an SNSPI imager for spectral response modulation to achieve computational spectral measurement.

[0124] Existing computational spectroscopy measurement techniques using superconducting nanowire detectors include:

[0125] Scheme (1): In a superconducting nanowire detector, n uniformly increasing bias currents are set to form n different spectral response modulation methods. Each bias current modulation can produce a different spectral responsivity for m different spectral data to be measured, thus constructing an n x m column spectral response matrix Φ. This superconducting nanowire detector can convert the spectral data to be measured x into the observed data y. The spectral response matrix Φ is used to solve for x = Φ. -1 The mathematical inverse problem of y allows us to recover the spectral data x to be measured from the observed data y.

[0126] The drawback of the above scheme is that when multiple bias currents are used to modulate the spectral response of the superconducting nanowire detector, the spectral responsivity data of the superconducting nanowire detector under different bias currents actually have low distinguishability, meaning that the spectral responsivity data are highly correlated with each other. These highly correlated data form the spectral response matrix Φ, implying that many rows of the spectral response matrix Φ are highly correlated or even overlap. This leads to a severe ill-conditioning of the spectral response matrix Φ, 10 4 ~10 7 The magnitude of the condition number ultimately affects the accuracy of the calculated spectral measurement. Furthermore, when using bias current modulation, even a small deviation in the bias current value can lead to a significant difference in the response rate. In calculated spectral measurements, it is difficult to guarantee that the bias current value of each observed data y is exactly the same as the bias current value of the spectral response matrix Φ. This small difference in the bias current value will introduce errors into the observed data y, ultimately affecting the solution of x = Φ. -1 The serious error caused by the mathematical inverse of y.

[0127] Scheme (2): In a width-gradient superconducting nanowire spectrosensor, n width-gradient superconducting nanowires are used to form n different spectral data-pulse amplitude modulation methods. Each modulation method can generate different pulse amplitude distributions for m different spectral data to be measured. The mapping relationship between spectral data and pulse amplitude here is the spectral response characteristic, which can be described as an n x m column spectral response matrix Φ. The superconducting nanowire spectrosensor converts the spectral data to be measured x into the observed data y. Then, the spectral response matrix Φ is used to solve for x = Φ. -1 The mathematical inverse problem of y allows us to recover the spectral data x to be measured from the observed data y.

[0128] The drawback of the above scheme is that the spectral response modulation result is obtained as pulses of different amplitudes. In reality, due to the reading noise of the circuit, a large error will be generated when reading the pulse amplitude, which is even larger than the error caused by setting the bias current in scheme (1). This method will also introduce a large error into the observed data y, ultimately leading to a problem in solving x = Φ. -1 The mathematical inverse of y produces serious errors.

[0129] To address the problems existing in the aforementioned related technologies, this application provides a computational spectral measurement scheme based on an SNSPI imager. To achieve computational spectral measurement of the SNSPI imager, this embodiment pre-calibrates the spectral response matrix Φ of the SNSPI imager. After completing the calibration of the spectral response matrix Φ, the data measurement and solution for the computational spectrum are performed. This embodiment includes the following steps:

[0130] Step 1: Preparations for calibrating the spectral response matrix Φ of the SNSPI imager

[0131] Assume that any row of the spectral response matrix Φ of the SNSPI imager has m spectral data whose responsivity needs to be calibrated, and assume that the wavelength range of the m spectral data to be calibrated is from λ. min To λ max First, an average wavelength of 0.5 × (λ) is selected. min +λ max Input the SNSPI imager. Then, gradually increase the bias current of the SNSPI imager from 0, and observe the change in the number of photon pulses per second (i.e., photon count rate) output by the SNSPI imager. Record the bias current I when the photon count rate of the SNSPI imager gradually saturates and no longer increases. max The value C at saturation max Then, the photon count rate of the SNSPI imager was recorded when it reached 0.5C. max bias current I at time Half and in I Half To I max Within the range, select any k bias currents {I1, I2, ..., I...} at equal intervals. k If only a bias current is set, the bias current can be selected as I. max .

[0132] Step 2: Set up the laser.

[0133] Select the first wavelength λ from the m spectral data wavelengths to be calibrated in step one, and emit laser light of wavelength λ using a tunable laser. Irradiate the laser onto a beam splitter with an energy ratio of 50% to 50%. The beam splitter inputs 50% of the laser energy to the optical power meter, and the remaining 50% of the laser energy is directed to the SNSPI imager. Record the power value p of the optical power meter at this point, and apply the photon energy formula... Find the number of photons N incident on the SNSPI imager per second. in , For example, here we need to control the energy of the tunable laser to achieve a photon count N per second. in Around 106. h is Planck's constant, and c is the speed of light.

[0134] Step 3: Read data from the SNSPI imager

[0135] Based on step two, the bias current of the SNSPI imager is set to I1 as in step one. At this point, once a photon from the laser emitted in step two is absorbed by a pixel of the SNSPI imager, a pair of reverse-propagating electrical pulses will be simultaneously generated at that pixel's location. A timing circuit is used to record the arrival times t of this pair of electrical pulses at the left and right ends of the SNSPI imager, respectively. L and t R Then calculate t. L and t R The electrical pulse time difference Δt. Since the length L of the SNSPI nanowire and the propagation speed v of the electrical pulse are known, the magnitude of this electrical pulse time difference Δt reflects the position of the pixel in which the SNSPI absorbs the photon.

[0136] Please see Figure 4 , Figure 4 This is a schematic diagram of an SNSPI imager generating electrical pulses according to an embodiment of this application. If the length of a single superconducting nanowire in the SNSPI imager is L, with the midpoint of the superconducting nanowire as the origin, and a photon is incident at an unknown position p, then position p generates a first pulse electrical signal propagating to the left and a second pulse electrical signal propagating to the right. Given the pulse propagation speed v, the position of the left end is -L / 2, and the position of the right end is L / 2, then the time t required for the first pulse electrical signal to reach the left end is... L = (L / 2 + p) / v, where t is the time t required for the second pulse signal to reach the right end. R = (L / 2 - p) / v, photon incident position p = (t L -t R )v / 2.

[0137] Step 4: Calculate the response rate of each SNSPI cell.

[0138] Based on step three, assuming SNSPI consists of n pixels, at least n×10 pixels are collected. 6 After collecting data on the time difference Δt of each electrical pulse, a histogram was plotted to statistically analyze all the time difference data, counting the frequency of each type of electrical pulse time difference. Please refer to [link / reference]. Figure 5 , Figure 5 This is a statistical histogram of electrical pulse time difference provided in an embodiment of this application. The horizontal axis represents the time difference (in nanoseconds), and the vertical axis represents the number of times the time difference occurs. Each statistical peak in the figure represents the number of pulse pairs generated by a pixel absorbing photons. Figure 5 As shown, the statistical histogram of the electrical pulse time difference data has n independent statistical peaks. These n peaks correspond one-to-one with the number of electrical pulse pairs generated by the absorption of photons by the n pixels in SNSPI. The number of electrical pulse time differences contained in each statistical peak is calculated sequentially and denoted as {S1, S2, ..., S...}. n} T Next, assuming the above n×10 is completed... 6 The data acquisition of the time difference of each electrical pulse took a total of T seconds. As can be seen from step two, the total number of photons actually irradiated by SNSPI within T seconds is N. in ×T (i.e., total number of photons). Finally, the number of electrical pulse time differences {S1, S2, ..., S} of each statistical peak is calculated. n} T Divide by the total number of photons N respectively in ×T, we can obtain the photon responsivity {φ1, φ2, ..., φ} of each pixel in SNSPI. n} T ,

[0139] Step 5: Complete the calibration of the SNSPI spectral response matrix under the first bias current I1.

[0140] Steps two through four above complete the calibration of the first wavelength λ among the m spectral data wavelengths required for calibration, obtaining the photon responsivity {φ} of each pixel in SNSPI at the first wavelength. 11 , φ 21 , ..., φ n1} T Then, change to a second wavelength and repeat steps two through four, measuring the photon responsivity {φ} of each pixel in the second wavelength SNSPI. 12 , φ 22 , ..., φ n2} T And so on, until the photon responsivity {φ} of each pixel in SNSPI at the m-th spectral data wavelength is obtained. 1m , φ 2m , ..., φnm} T All photon responsivity data are arranged column-wise to form an n x m spectral response matrix Φ. (1) .

[0141] Step 6: Repeat steps 2 to 5 to complete the calibration of the spectral response matrix Φ of SNSPI under all bias currents.

[0142] Steps two through five only completed the n x m spectral response matrix Φ under the first bias current I1. (1) Calibration. Typically, only the spectral response matrix Φ under the first bias current in step one is measured. (1 This is sufficient for computational spectral measurements. However, to obtain a more informative spectral response matrix and achieve more accurate computational spectral measurement results, this method further proposes the following: changing the second bias current I2 to complete the second n-row, m-column spectral response matrix Φ. (2) Calibration. This process continues until the n x m spectral response matrix Φ under the k-th bias current is obtained. (k) Calibration. Finally, the k n x m spectral response matrices are arranged sequentially according to their row directions to form an nk x m spectral response matrix:

[0143]

[0144] Step 7: Measure the observed data y of the unknown spectral data x.

[0145] In this embodiment, the unknown spectral data (i.e., the polychromatic light to be measured) is irradiated onto the SNSPI, and the bias current value of the SNSPI is set to I1 in step one. Similar to step three, a timing circuit is used to record the timestamps of the electrical pulses arriving at the left and right ends of the SNSPI imager. L and t R Then, the computer is used to calculate t. L and t R The electrical pulse time difference Δt. Similar to step four, at least n×10 can be collected. 6 After collecting data on the time differences Δt of each electrical pulse, the frequency of each type of electrical pulse time difference is counted. This will result in n statistical peaks in the histogram of these frequency counts. The number of electrical pulse time differences contained in each statistical peak is then calculated and denoted as the observed data y. (1) = [y1, y2, ..., y n ] T .

[0146] Typically, the spectral response matrix Φ under the first bias current in step one is measured. (1) With observation data y (1)This is sufficient for computational spectral measurements. However, to achieve more accurate computational spectral measurement results, the observation data needs to match the row number of the nk rows in the more informative spectral response matrix described in step five. Therefore, k types of observation data are required. This method further proposes the following: changing the second bias current I2 to obtain the second observation data y. (2) The measurements are repeated until the observation data y under the k-th bias current is completed. (k) The measurements were then taken. Finally, the k observations were arranged sequentially to form the following nk rows of observation data y:

[0147]

[0148] Step 8: Calculate and solve for the spectral data x to be measured.

[0149] Solve for Φ using the observation data y from step seven and the spectral response matrix Φ from step six. -1 The mathematical inverse problem of y has a solution that is the spectral data x to be measured. When using only a single bias current, the observed data y is used. (1) Step 6: Spectral response matrix Φ (1) Solve The mathematical inverse problem is such that the solution is the spectral data x to be measured. There are various ways to solve this mathematical inverse problem; this embodiment uses the truncated generalized singular value decomposition method as the solution method.

[0150] Please see Figure 6 , Figure 6 This is a schematic diagram of an SNSPI spectral response matrix calibration process provided in an embodiment of this application. After the processing operations in steps one and two described above, a tunable laser can be controlled to generate m wavelengths of laser light and illuminate a 50% to 50% beam splitter. The beam splitter inputs a portion of the laser light into an optical power meter and another portion into the SNSPI imager. In step two, the optical power meter can be used to record the total number of photons during calibration. In step three, k bias currents can be set, and the bias currents applied to the SNSPI imager through a current source cause the SNSPI imager to generate electrical pulse pairs. The timing circuit can transmit the time difference data of the electrical pulse pairs of n pixels to a computer so that the responsivity of each SNSPI pixel can be calculated in step four, and then the spectral response matrix Φ of nk rows and m columns can be obtained through steps five and six.

[0151] Please see Figure 7 , Figure 7This is a schematic diagram illustrating the SNSPI spectral observation data and calculation process provided in an embodiment of this application. In step seven, the unknown spectral data (i.e., the polychromatic light to be measured) is irradiated onto the SNSPI imager. k bias currents are set, and the bias currents applied to the SNSPI imager through a current source generate electrical pulse pairs. The timing circuit transmits the time difference data of the electrical pulse pairs of n pixels to the computer to obtain the observation data y for row nk. Step eight solves for x = Φ. -1 By using y, the unknown spectral data x can be obtained.

[0152] This embodiment implements a computational spectral measurement technique for low condition number spectral response matrix in superconducting nanowire detectors. This technique not only improves the stability of computational spectral measurements in superconducting nanowire detectors but also brings a new and stable measurement method to the entire field of computational spectral measurement.

[0153] This embodiment implements a computational spectral measurement of a low condition number spectral response matrix in a superconducting nanowire detector. The condition number of the spectral response matrix of the SNSPI imager used in this embodiment is lower than that of existing superconducting nanowire detector spectral response matrices in the art. This embodiment requires only one or a few bias currents to achieve spectral response modulation, avoiding data errors caused by significant bias current fluctuations. Simultaneously, this solution eliminates the need to record pulse amplitude information, avoiding data errors caused by inaccurate pulse amplitude measurements. This embodiment provides a feasible method for computational spectral measurement using an SNSPI imager, enabling existing systems using SNSPI for area array imaging to also possess computational spectral measurement capabilities, significantly expanding the information dimension and amount measured by the SNSPI imager.

[0154] Please see Figure 8 , Figure 8 This is a schematic diagram showing the comparison of the spectral response matrix of an existing solution in the art with that of this solution, as provided in an embodiment of this application. Figure 8 The diagram shows a spectral response matrix A generated using a superconducting nanowire detector, as provided in the embodiments of this application, and also shows a spectral response matrix B generated using a scheme based on an SNSPI imager. Figure 8 In the spectral response matrix A, the vertical axis represents the bias current in microamps; the horizontal axis represents the wavelength in nanometers; and the vertical axis represents the photon responsivity. Figure 8 In the spectral response matrix B, the vertical axis represents the SNSPI pixel number; the horizontal axis represents the wavelength in nanometers; and the vertical axis represents the photon responsivity.

[0155] Existing methods in this field employ superconducting nanowire detectors, calibrating the spectral response matrix by setting different bias currents (i.e., the vertical axis in the figure). The existing measurement method has a condition number of 15501 for the spectral response matrix across 10 wavelength channels in the 1550-1559 nm band, and the calculated mean square error of the spectral measurement is 0.0534.

[0156] This embodiment uses an SNSPI imager, and the spectral response matrix is ​​calibrated using the spectral response characteristics of multiple pixels (i.e., the vertical axis in the figure) in the SNSPI imager. Compared with the same experimental conditions described above, the condition number of the spectral response matrix for 10 wavelength channels in the 1550-1559nm band in this embodiment is equal to 719, and the mean square error of the calculated spectral measurement is equal to 0.0052.

[0157] The condition number of existing solutions in the art is approximately 21.6 times that of this solution (15501 / 719). The root mean square error of this solution is approximately 0.0036 / 0.0534 ≈ 0.067 compared to the existing solutions. In other words, the condition number of the SNSPI spectral response matrix using this embodiment is reduced by more than one order of magnitude compared to the condition number of the spectral response matrix of existing superconducting nanowire detectors, and the root mean square error of the calculated spectral measurement results is reduced by 93% compared to the aforementioned existing solutions.

[0158] Please see Figure 9 , Figure 9 This is a schematic diagram of the structure of a spectral calibration system provided in an embodiment of this application. The system may include:

[0159] The bias current setting module 901 is used to set the current bias current value of the SNSPI imager;

[0160] The laser setting module 902 is used to set the energy value of the laser so that the photon output rate of the laser to the SNSPI imager reaches a preset value.

[0161] The responsivity calculation module 903 is used to emit lasers sequentially to the SNSPI imager according to each wavelength of the spectral data to be calibrated using the laser, to obtain the electrical pulse time difference of the pixels in the SNSPI imager, and to calculate the photon responsivity of the pixel to each wavelength of the spectral data to be calibrated based on the electrical pulse time difference; wherein, the electrical pulse time difference is the time difference between the electrical pulse generated after the pixel absorbs a photon and the two ends of the SNSPI imager where the pixel is located.

[0162] The matrix construction module 904 is used to construct the spectral response matrix of the SNSPI imager based on the photon responsivity, thereby completing the spectral calibration.

[0163] This embodiment sets the current bias current value of the SNSPI imager and the energy value of the laser, and sequentially emits laser light to the SNSPI imager according to each wavelength of the spectral data to be calibrated, so as to measure the spectral data using an SNSPI imager comprising multiple pixels. After a pixel of the SNSPI imager absorbs a photon, it generates an electrical pulse. This embodiment calculates the photon responsivity of each pixel to each wavelength based on the time difference between the electrical pulses arriving at the two ends of the superconducting nanowire single-photon imager where the pixel is located. Based on the photon responsivity, the spectral response matrix of the SNSPI imager can be constructed, thereby realizing the spectral calibration of the SNSPI imager. The above method can achieve spectral calibration of the spectral imager, reduce the condition number of the spectral response matrix, and improve measurement accuracy.

[0164] Furthermore, the bias current setting module 901 includes:

[0165] The wavelength determination unit is used to determine the wavelength range of all spectral data to be calibrated; it is also used to set the midpoint value of the wavelength range as the target wavelength.

[0166] The current testing unit is used to emit laser light of the target wavelength into the SNSPI imager using the laser; it is also used to increase the bias current of the SNSPI imager and record the photon output rate of the SNSPI imager; and it is also used to determine the saturated photon output rate when the photon output rate of the SNSPI imager reaches saturation.

[0167] The current setting unit is used to set the bias current value corresponding to the saturated photon output rate to the saturated current value; and is also used to set the current bias current value of the SNSPI imager according to the saturated current value.

[0168] Furthermore, the process by which the current setting unit sets the current bias current value of the SNSPI imager based on the saturation current value includes: setting the bias current value corresponding to the half-saturation photon output rate as the half-saturation current value; wherein the half-saturation photon output rate is half of the saturation photon output rate; constructing a candidate current value range with an upper bound of the saturation current value and a lower bound of the half-saturation current value; selecting multiple candidate current values ​​from the candidate current value range, and setting the candidate current values ​​as the current bias current value of the SNSPI imager.

[0169] Furthermore, the matrix construction module 904 is used to generate a spectral response submatrix based on the photon responsivity of the pixel to each wavelength at each current bias current value; and is also used to construct the spectral response matrix of the SNSPI imager based on all the spectral response submatrixes.

[0170] Furthermore, the laser setting module 902 includes:

[0171] A wavelength selection unit is used to select a test wavelength from the wavelengths of the spectral data to be calibrated.

[0172] A laser emitting unit is used to control the laser to emit laser light toward the beam splitter according to the test wavelength, so that the beam splitter illuminates the optical power meter and the SNSPI imager with the laser light according to a preset ratio;

[0173] A photon output rate determination unit is used to calculate the current photon output rate of the laser to the SNSPI imager based on the power value detected by the optical power meter and the preset ratio.

[0174] An energy adjustment unit is used to adjust the energy value of the laser according to the current photon output rate of the laser to the SNSPI imager, so that the photon output rate of the laser to the SNSPI imager reaches the preset value.

[0175] Furthermore, the responsivity calculation module 903 is used to select the current calibration wavelength from the wavelengths of the spectral data to be calibrated; it is also used to emit lasers sequentially to the SNSPI imager according to the current calibration wavelength using the laser to obtain the electrical pulse time difference of the pixels in the SNSPI imager; it is also used to calculate the photon responsivity of the pixel to the current calibration wavelength based on the electrical pulse time difference; it is also used to determine whether all wavelengths of the spectral data to be calibrated have been selected; if not, it proceeds to the step of selecting the current calibration wavelength from the wavelengths of the spectral data to be calibrated.

[0176] Furthermore, the process by which the response rate calculation module 903 calculates the photon responsivity of the pixel to the current calibration wavelength based on the electrical pulse time difference includes: generating a statistical histogram corresponding to all the electrical pulse time differences; determining n statistical peaks in the statistical histogram; wherein, the statistical peaks correspond one-to-one with the pixels; and using the ratio of the number of electrical pulse time differences contained in each statistical peak to the total number of photons as the photon responsivity of the corresponding pixel to the current calibration wavelength.

[0177] Furthermore, it also includes:

[0178] The pixel selection module is used to set the pixels in the SNSPI imager that meet the preset conditions as target pixels; wherein, the preset conditions are: the composite degree (correlation coefficient) of the spectral response curve of the target pixel with the spectral response curve of other pixels is lower than a preset value.

[0179] Accordingly, the process by which the response rate calculation module 903 calculates the photon response rate of the pixel to each wavelength in the spectral data to be calibrated based on the electrical pulse time difference includes: calculating the photon response rate of the target pixel to each wavelength in the spectral data to be calibrated based on the electrical pulse time difference.

[0180] Please see Figure 10 , Figure 10 This is a schematic diagram of the structure of a spectral data measurement system provided in an embodiment of this application. The system may include:

[0181] Task receiving module 1001 is used to receive spectral data measurement tasks;

[0182] Measurement module 1002 is used to illuminate the polychromatic light to be measured corresponding to the spectral data measurement task onto the SNSPI imager to obtain observation data;

[0183] The conversion module 1003 is used to convert the observation data into corresponding spectral data using the spectral response matrix;

[0184] The SNSPI imager and the spectral response matrix are the SNSPI imager and spectral response matrix in the above-mentioned spectral calibration method.

[0185] In this embodiment, after receiving a spectral data measurement task, an SNSPI imager is used to acquire observation data, and the spectral response matrix is ​​used to convert the observation data into corresponding spectral data. This embodiment utilizes an SNSPI imager to achieve spectral data detection, which can reduce the condition number of the spectral response matrix and improve the measurement accuracy of spectral data.

[0186] Since the embodiments of the system part correspond to the embodiments of the method part, please refer to the description of the embodiments of the method part for the embodiments of the system part, and they will not be repeated here.

[0187] This application also provides a storage medium on which a computer program is stored, which, when executed, can perform the steps provided in the above embodiments. The storage medium may include various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0188] This application also provides an electronic device that may include a memory and a processor. The memory stores a computer program, and when the processor calls the computer program in the memory, it can implement the steps provided in the above embodiments. Of course, the electronic device may also include various network interfaces, power supplies, and other components.

[0189] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

[0190] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A spectral calibration method, characterized in that, include: Set the current bias current value of the SNSPI imager; Set the energy value of the laser so that the photon output rate of the laser to the SNSPI imager reaches a preset value; The laser is used to sequentially emit laser light into the SNSPI imager according to each wavelength of the spectral data to be calibrated, thereby obtaining the electrical pulse time difference of the pixels in the SNSPI imager, and calculating the photon responsivity of the pixel to each wavelength of the spectral data to be calibrated based on the electrical pulse time difference; wherein, the electrical pulse time difference is the time difference between the electrical pulse generated after the pixel absorbs a photon and the two ends of the SNSPI imager where the pixel is located. The spectral response matrix of the SNSPI imager is constructed based on the photon responsivity to complete the spectral calibration. Specifically, the laser is used to sequentially emit laser light into the SNSPI imager according to each wavelength of the spectral data to be calibrated, thereby obtaining the electrical pulse time difference of the pixels in the SNSPI imager, and calculating the photon responsivity of the pixel to each wavelength of the spectral data to be calibrated based on the electrical pulse time difference, including: Select the current calibration wavelength from the wavelengths of the spectral data to be calibrated; The laser is used to sequentially emit lasers at the SNSPI imager according to the current calibration wavelength to obtain the electrical pulse time difference of the pixels in the SNSPI imager; Generate statistical histograms corresponding to all the time differences of the electrical pulses; Identify n statistical peaks in the statistical histogram; wherein, each statistical peak corresponds one-to-one with a pixel; The ratio of the number of electrical pulse time differences contained in each statistical peak to the total number of photons is used as the photon responsivity of the corresponding pixel to the current calibrated wavelength. Determine whether all wavelengths of the spectral data to be calibrated have been selected; If not, proceed to the step of selecting the current calibration wavelength from the wavelengths of the spectral data to be calibrated.

2. The spectral calibration method according to claim 1, characterized in that, Setting the current bias current value of the SNSPI imager includes: Determine the wavelength range for all spectral data to be calibrated; Set the midpoint value of the wavelength range as the target wavelength; The laser is used to emit a laser of the target wavelength toward the SNSPI imager; Increase the bias current of the SNSPI imager and record the photon output rate of the SNSPI imager; Determine the saturated photon output rate when the photon output rate of the SNSPI imager reaches saturation. Set the bias current value corresponding to the saturated photon output rate as the saturated current value; The current bias current value of the SNSPI imager is set according to the saturation current value.

3. The spectral calibration method according to claim 2, characterized in that, Setting the current bias current value of the SNSPI imager based on the saturation current value includes: The bias current value corresponding to the half-saturated photon output rate is set as the half-saturated current value; wherein, the half-saturated photon output rate is half of the saturated photon output rate; Construct a range of candidate current values ​​with an upper bound of the saturation current value and a lower bound of the half-saturation current value; Multiple alternative current values ​​are selected from the range of alternative current values, and the alternative current values ​​are set as the current bias current values ​​of the SNSPI imager.

4. The spectral calibration method according to claim 3, characterized in that, The spectral response matrix of the SNSPI imager is constructed based on the photon responsivity, including: Generate a spectral response submatrix based on the photon responsivity of the pixel to each wavelength at each current bias current value; The spectral response matrix of the SNSPI imager is constructed based on all the spectral response sub-matrices.

5. The spectral calibration method according to claim 1, characterized in that, Setting the energy value of the laser to achieve a preset photon output rate for the SNSPI imager includes: Select the test wavelength from the wavelengths of the spectral data to be calibrated; The laser is controlled to emit laser light toward the beam splitter according to the test wavelength, so that the beam splitter illuminates the optical power meter and the SNSPI imager with the laser light according to a preset ratio; The current photon output rate of the laser to the SNSPI imager is calculated based on the power value detected by the optical power meter and the preset ratio. The energy value of the laser is adjusted according to the current photon output rate of the laser to the SNSPI imager, so that the photon output rate of the laser to the SNSPI imager reaches the preset value.

6. The spectral calibration method according to any one of claims 1 to 5, characterized in that, Before calculating the photon responsivity of the pixel to each wavelength in the spectral data to be calibrated based on the electrical pulse time difference, the method further includes: Pixels in the SNSPI imager that meet preset conditions are set as target pixels; wherein, the preset conditions are: the composite degree of the spectral response curve of the target pixel with the spectral response curve of other pixels is lower than a preset value; Accordingly, calculating the photon responsivity of the pixel to each wavelength in the spectral data to be calibrated based on the electrical pulse time difference includes: The photon responsivity of the target pixel to each wavelength in the spectral data to be calibrated is calculated based on the time difference of the electrical pulse.

7. A spectral calibration system, characterized in that, include: The bias current setting module is used to set the current bias current value of the SNSPI imager; A laser setting module is used to set the energy value of the laser so that the photon output rate of the laser to the SNSPI imager reaches a preset value. The responsivity calculation module is used to sequentially emit laser light to the SNSPI imager according to each wavelength of the spectral data to be calibrated using the laser, obtain the electrical pulse time difference of the pixels in the SNSPI imager, and calculate the photon responsivity of the pixel to each wavelength of the spectral data to be calibrated based on the electrical pulse time difference; wherein, the electrical pulse time difference is the time difference between the electrical pulse generated after the pixel absorbs a photon and the two ends of the SNSPI imager where the pixel is located. The matrix construction module is used to construct the spectral response matrix of the SNSPI imager based on the photon responsivity, thereby completing the spectral calibration. The responsivity calculation module is configured to: select a current calibration wavelength from the wavelengths of the spectral data to be calibrated; emit laser light sequentially to the SNSPI imager according to the current calibration wavelength using the laser to obtain the electrical pulse time difference of the pixels in the SNSPI imager; calculate the photon responsivity of the pixel to the current calibration wavelength based on the electrical pulse time difference; and determine whether all wavelengths of the spectral data to be calibrated have been selected; if not, proceed to the step of selecting the current calibration wavelength from the wavelengths of the spectral data to be calibrated. The process by which the responsivity calculation module calculates the photon responsivity of the pixel to the current calibration wavelength based on the electrical pulse time difference includes: generating a statistical histogram corresponding to all the electrical pulse time differences; determining n statistical peaks in the statistical histogram; wherein, the statistical peaks correspond one-to-one with the pixels; and using the ratio of the number of electrical pulse time differences contained in each statistical peak to the total number of photons as the photon responsivity of the corresponding pixel to the current calibration wavelength.

8. A method for measuring spectral data, characterized in that, include: Receive spectral data measurement tasks; The polychromatic light to be measured corresponding to the spectral data measurement task is irradiated onto the SNSPI imager to obtain the observation data; The observed data are converted into corresponding spectral data using the spectral response matrix; Wherein, the SNSPI imager and the spectral response matrix are the SNSPI imager and spectral response matrix in the spectral calibration method of any one of claims 1 to 6.

9. A spectral data measurement system, characterized in that, include: The task receiving module is used to receive spectral data measurement tasks; The measurement module is used to illuminate the polychromatic light to be measured corresponding to the spectral data measurement task onto the SNSPI imager to obtain observation data; A conversion module is used to convert the observed data into corresponding spectral data using the spectral response matrix; Wherein, the SNSPI imager and the spectral response matrix are the SNSPI imager and spectral response matrix in the spectral calibration method of any one of claims 1 to 6.

10. An electronic device, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program, and the processor, when calling the computer program in the memory, implements the steps of the spectral calibration method as described in any one of claims 1 to 6 and / or the steps of the spectral data measurement method as described in claim 8.

11. A storage medium, characterized in that, The storage medium stores computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the spectral calibration method as described in any one of claims 1 to 6 and / or the steps of the spectral data measurement method as described in claim 8.

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