An optical path structure, a spectrometer, a spectral signal processing method and an electronic device

Abstract

Embodiments of the present application provide a kind of optical path structure, spectrometer and spectrum signal processing method, electronic equipment, light source and sample module generate target light beam to be analyzed, after being obtained by incidence slit and spherical collimating mirror parallel light beam, echelle grating is used to carry out dispersion to parallel light beam in first direction, shear interference plate will be dispersed in first direction Parallel light beam, in second direction interference, second direction is perpendicular to first direction, cylindrical mirror is used to reflect the light beam after interference, and focus to photoelectric sensor in first direction, the energy of the light of a certain wavelength can be distributed in interference direction, by all pixels of photoelectric sensor in interference direction, it is more evenly borne, so as to improve the sensitivity of photoelectric sensor to measure light beam.Signal processing module carries out Fourier transform in spatial frequency domain according to the electrical signal converted by photoelectric sensor, calculates the spectral characteristic information of target light beam, can also eliminate dark current, average noise, and improve signal-to-noise ratio.

Description

Technical Field

[0001] This invention relates to the field of spectral analysis technology, and in particular to an optical path structure, a spectrometer and a spectral signal processing method, and electronic equipment. Background Technology

[0002] The emergence and rise of spectroscopic detection technology has enabled humanity to make a qualitative leap in its ability to conduct in-depth research on things of interest. After more than two decades of rapid development, spectroscopic detection technology has formed a distinctive modern discipline.

[0003] A slit spectrometer is an instrument used to measure the wavelength distribution of light. The basic principle of a slit spectrometer is that light passes through a slit and is dispersed by a beam-splitting element such as a grating or prism, separating light of different wavelengths. These separated light beams are then detected and recorded by a receiver. By measuring the light intensity at different wavelengths, a spectrum can be plotted, showing the wavelength distribution of the light.

[0004] Slit spectrometers have wide applications in many fields, including physics, chemistry, biology, and astronomy. They can be used to analyze the composition of substances, measure the spectral characteristics of light sources, and study the interaction between light and matter. Through slit spectrometers, we can obtain information about the wavelength, intensity, and spectrum of light, thus gaining a deeper understanding of the properties of light and the characteristics of matter. Compared to ordinary spectrometers, echelle grating spectrometers are spectrometers with stronger dispersive capabilities and are often used to analyze the fine structure of spectra. Conventional echelle grating spectrometers use an echelle grating as the first-order dispersive element and a dispersive prism as the second-order dispersive element. However, the aforementioned spectrometer with an echelle grating and dispersive prism is more suitable for dense, continuous measurements across the entire spectrum. For sparse spectra, such as elemental emission spectra, the spectrometer sensor target surface will only show many scattered points in a certain row. This is because the sensitivity adjustment of the spectrometer sensor is usually global and cannot be adjusted for individual pixels. Since the light intensity of different scattered points varies greatly, the sensitivity of the measurement results depends on the dynamic range and noise of individual pixels. Some high-energy scatter points may cause measurement results to overflow or even damage the pixels. On the other hand, if the sensor sensitivity is reduced, some darker spectral points may be masked by the dark current and noise of the pixels, resulting in inaccurate measurements. Summary of the Invention

[0005] The purpose of this invention is to provide an optical path structure, a spectrometer, a spectral signal processing method, and an electronic device to improve the sensitivity of spectral analysis using an echelle grating spectrometer. The specific technical solution is as follows:

[0006] An optical path structure includes: a light source and sample module, a beam splitting module, and a photoelectric sensor; wherein,

[0007] The light source and sample module are used to generate the target beam to be analyzed.

[0008] The beam splitting module includes an entrance slit, a spherical collimating mirror, an echelle grating, a shearing interferometer, and a cylindrical mirror.

[0009] The entrance slit is used to receive the target beam;

[0010] The echelle grating disperses the parallel beam obtained after passing through the entrance slit and the spherical collimating mirror in the first direction.

[0011] The shearing interference plate is used to interfere the parallel beam after the dispersion of the echelle grating in a second direction, which is perpendicular to the first direction.

[0012] The cylindrical mirror is used to reflect the interfered light beam and focus it onto the photoelectric sensor in the first direction;

[0013] The photoelectric sensor is used to convert the received target beam from an optical signal into an electrical signal and send it to a signal processing module electrically connected to it, so that the signal processing module can perform a spatial frequency domain Fourier transform based on the converted electrical signal and calculate the spectral characteristic information of the target beam.

[0014] Optionally, the light source and sample module, the entrance slit, and the spherical collimating lens are arranged on the same optical axis.

[0015] Optionally, the entrance slit is a light-shielding plate with a slit, and the slit is aligned with the spherical collimating lens so that the target beam passes through the slit and illuminates the spherical collimating lens;

[0016] The spherical collimating mirror is a concave reflecting mirror, which faces the slit and is used to collimate the target beam into a parallel beam.

[0017] Optionally, the diffraction order of the echelle grating is greater than 30.

[0018] Optionally, the shearing interference plate includes: a wedge-shaped optical glass plate, the top surface of which is a semi-transparent and semi-reflective first reflecting surface, and the bottom surface of which is a total internal reflection second reflecting surface, wherein the first reflecting surface and the second reflecting surface form a wedge-shaped angle of the optical glass plate.

[0019] Optionally, the cylindrical reflector has a cylindrical concave mirror facing the shearing interference plate. The axis of the cylindrical concave mirror is parallel to the direction of interference, used to focus the interfered light beam in the direction of dispersion, maintain it in the direction of interference, and reflect it to the photoelectric sensor.

[0020] Optionally, the photoelectric sensor is a two-dimensional image receiving sensor.

[0021] A spectrometer includes: the aforementioned optical path structure, signal processing module, and display module;

[0022] The signal processing module is electrically connected to the photoelectric sensor and the display module, respectively;

[0023] The signal processing module performs a spatial frequency domain Fourier transform on the electrical signal converted by the photoelectric sensor, calculates the spectral characteristic information of the target beam, and displays it through the display module.

[0024] A spectral signal processing method is applied to the signal processing module of the aforementioned spectrometer, wherein the dispersion direction of the target beam is transverse to the photoelectric sensor, and the interference direction of the target beam is longitudinal to the photoelectric sensor; the method includes:

[0025] The vertical pixel data of the photoelectric sensor is obtained for each column, and each column of pixel data includes: pixel coordinate information and pixel brightness information;

[0026] Based on the pixel coordinate information and pixel brightness information of each column of pixel data, a spatial frequency domain Fourier transform is performed on each column of pixel data in sequence to calculate the beam frequency domain sequence corresponding to each column of pixel data. The beam frequency domain sequence includes the corresponding data of beam frequency and beam intensity.

[0027] By statistically analyzing the frequency domain data of the beams calculated from each column of pixel data, the corresponding data of all beam frequencies and all beam intensities are established, generating the spectral characteristic information of the target beam.

[0028] An electronic device includes a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus;

[0029] Memory, used to store computer programs;

[0030] The processor, when executing the program stored in the memory, implements the above-described spectral signal processing method.

[0031] Beneficial effects of the embodiments of the present invention:

[0032] The optical path structure provided in this embodiment of the invention includes a light source and sample module that generates a target beam to be analyzed. After passing through an entrance slit and a spherical collimating lens, a parallel beam is obtained. A middle-elliptic grating is used to disperse the parallel beam in a first direction. A shearing interferometer plate interferes with the dispersed parallel beam in a second direction, perpendicular to the first direction. A cylindrical mirror reflects the interfered beam and focuses it onto the photoelectric sensor in the first direction. Compared to existing technologies, the energy of light of a certain wavelength can be distributed along the interference direction, and is more evenly distributed among all pixels of the photoelectric sensor in that direction, thereby improving the sensitivity of the photoelectric sensor in measuring the beam. Furthermore, the signal processing module, electrically connected to the photoelectric sensor, performs a spatial frequency domain Fourier transform on the electrical signal converted by the photoelectric sensor to calculate the spectral characteristics of the target beam. This effectively eliminates dark current, averages noise, and improves the signal-to-noise ratio.

[0033] Of course, implementing any product or method of the present invention does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0035] Figure 1 This is a schematic diagram of a two-dimensional array sensor for a stepped grating spectrometer used in this application to image signals acquired from a target surface.

[0036] Figure 2 for Figure 1 A schematic diagram of the image formed by grating dispersion in the spectrometer shown;

[0037] Figure 3 for Figure 1 The diagram shows the image formed after dispersion by the grating and prism of the spectrometer.

[0038] Figure 4 This is a schematic diagram of an optical path structure provided in Embodiment 1 of this application;

[0039] Figure 5 for Figure 4 A top-view schematic diagram of the optical path structure shown;

[0040] Figure 6 for Figure 4 A schematic diagram of the imaging of the photoelectric sensor in the optical path structure shown;

[0041] Figure 7 This is a schematic diagram of the electrical connection structure of a spectrometer provided in Embodiment 2 of this application;

[0042] Figure 8 This is a flowchart illustrating a spectral signal processing method provided in Embodiment 3 of this application;

[0043] Figure 9 for Figure 8 A schematic diagram of the frequency domain sequence function relationship of a column of pixel data in the spectral signal processing method shown;

[0044] Figure 10 This is a schematic diagram of the imaging of the electrical sensor in the verification embodiment of this application;

[0045] Figure 11 This is a spectral characteristic information diagram of a mercury argon lamp measured in a verification embodiment of this application;

[0046] Figure 12 This is a schematic diagram of the structure of an electronic device provided in Embodiment 5 of this application.

[0047] The attached figures are labeled as follows:

[0048] The light source and sample module 10, the entrance slit 21, the spherical collimating lens 22, the echelle grating 23, the first reflecting surface 231, the second reflecting surface 232, the shearing interference plate 24, the cylindrical mirror 25, and the photoelectric sensor 31.

[0049] Signal processing module 32, display module 33.

[0050] Processor 41, communication interface 42, memory 43, communication bus 44. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of the present invention.

[0052] In a comparative embodiment of the spectrometer provided in this application, the spectrometer utilizes prisms and grating dispersive components for imaging.

[0053] From the grating resolution formula, we know that R = λ / Dλ = m·N. Improving resolution can be achieved by increasing the total number of grating lines N or by using higher diffraction orders. An echelle grating is a type of grating with a very high diffraction order. Spectroscopic instruments made with echelle gratings are characterized by small size, high dispersion, and high resolution. In this comparative embodiment, an echelle grating is used. In the spectrometer of this comparative embodiment, through the action of the echelle grating and the dispersive prism, light of different orders is separated longitudinally, i.e., cross-dispersion occurs, thereby transforming the one-dimensional spectrum into a two-dimensional spectrum. Simultaneously, a highly sensitive two-dimensional array sensor is used to detect the signal on the target surface. Figure 1 This is a schematic diagram of a two-dimensional array sensor for a stepped grating spectrometer used in this application to image signals acquired from a target surface. (See attached diagram.) Figure 1 As shown, the acquired signal exhibits a multi-layered horizontal stripe pattern. Each horizontal row in the image represents a small, fine range within a spectral sub-level, typically a few nanometers in size; while the vertical rows represent different sub-levels, encompassing a larger spectral range. The computer can stitch together the data vertically and then horizontally to obtain a complete spectrum. This is the operating method of a traditional echelle grating spectrometer.

[0054] Specifically, echelle gratings have a relatively large grating constant, meaning a lower line density. Simultaneously, the small, angled planes within the grooves serve as the working surfaces, resulting in a large blaze angle, typically above 60 degrees. According to the simplified calculation equation for gratings: mλ = 2dsinθ, where m is the diffraction order, λ is the diffraction wavelength, d is the grating constant, and θ is the diffraction angle, the echelle grating, with its large grating constant d (i.e., line spacing) and large blaze angle, generally exhibits a diffraction order above 30.

[0055] This means that although the resolution within the same order of the spectrum is high, there is significant overlap between different orders. For example, 532 nm in the 30th-order diffraction, 514.8 nm in the 31st-order diffraction, and 498.75 nm in the 32nd-order diffraction (the wavelength is the same as the product of the order). Figure 2 for Figure 1 The diagram shown is an image of the spectrometer after grating dispersion. Figure 2 As shown, light of these wavelengths, such as 532nm and 354.7nm, cannot be separated by an echelle grating and overlaps after passing through the grating.

[0056] A dispersive prism can separate light of different secondary orders longitudinally (and laterally within the secondary order), a process known as cross dispersion. Figure 3 for Figure 1 The diagram shows the image formed by the dispersion of the grating and prism in the spectrometer, as shown below. Figure 3 As shown, a dispersive prism transforms a one-dimensional spectrum into a two-dimensional spectrum. However, due to... Figure 3The spectrum in the image is sparse, and many scattered points (341nm, 532nm, 354.7nm, 540nm) will only appear on a certain row on the target surface of the spectrometer sensor. The sensitivity adjustment of the target surface of the spectrometer sensor is global, which leads to low sensitivity of the spectrometer sensor and poor accuracy of the measured spectral information.

[0057] Example 1

[0058] To address the aforementioned issues, this application provides a medium-sized echelle grating spectrometer.

[0059] Figure 4 This is a schematic diagram of an optical path structure provided in an embodiment of this application. Figure 5 for Figure 4 The diagram shows a top view of the optical path structure. Please refer to [link / reference]. Figure 4 and Figure 5 As shown, the optical path structure provided in this embodiment includes: a light source and sample module 10, a beam splitting module, and a photoelectric sensor 31. The light source and sample module 10 generates the target beam to be analyzed. The beam splitting module includes an entrance slit 21, a spherical collimating mirror 22, an echelle grating 23, a shearing interferometer 24, and a cylindrical mirror 25. The entrance slit 21 receives the target beam. The echelle grating 23 directs the parallel beam obtained after passing through the entrance slit 21 and the spherical collimating mirror 22 in a first direction (the first direction is as shown in the image). Figure 4 The shearing interference plate 24 is used to disperse the parallel beam after dispersion by the echelle grating 23 in a second direction (the second direction can be as shown in the x-direction). Figure 4 The beam is interfered with in the y-direction shown, and the second direction is perpendicular to the first direction. The cylindrical reflector 25 is used to reflect the interfered beam and focus it onto the photoelectric sensor 31 in the first direction. The photoelectric sensor 31 is used to convert the received target beam from an optical signal into an electrical signal and send it to a signal processing module electrically connected to it, so that the signal processing module can perform a spatial frequency domain Fourier transform based on the converted electrical signal to calculate the spectral characteristic information of the target beam.

[0060] The optical path structure provided in this embodiment of the invention includes a light source and sample module 10 that generates a target beam to be analyzed. After passing through an entrance slit 21 and a spherical collimating lens 22, a parallel beam is obtained. An echelle grating 23 is used to disperse the parallel beam in a first direction. A shearing interference plate 24 interferes with the parallel beam dispersed in the first direction in a second direction, which is perpendicular to the first direction. A cylindrical reflector 25 is used to reflect the interfered beam and focus it onto the photoelectric sensor 31 in the first direction.

[0061] Figure 6 for Figure 4 Please refer to the imaging schematic diagram of the photoelectric sensor in the optical path structure shown. Figure 6 As shown, the energy of light of a certain wavelength (341nm, 532nm, 354.7nm, 540nm) can be distributed along the interference direction. Compared to the contrast implementation, the energy is more evenly distributed across all pixels of the photoelectric sensor 31 along the interference direction, thereby improving the sensitivity of the photoelectric sensor 31 in measuring the light beam. Figure 6 As shown, light beams with wavelengths of 532nm and 354.7nm cannot be separated by the echelle grating and are located in the same column of the photoelectric sensor 31. The target light beam appears as an alternating bright and dark pattern along the column direction. Using a signal processing module electrically connected to the photoelectric sensor 31, the spectral characteristics of the target light beam are calculated by performing a Fourier transform in the spatial frequency domain based on the electrical signal converted by the photoelectric sensor 31. This can also effectively eliminate dark current, average noise, and improve the signal-to-noise ratio.

[0062] like Figure 4 As shown, the light source and sample module 10, the entrance slit 21, and the spherical collimating mirror 22 are arranged along the same optical axis. The entrance slit 21 restricts the target beam emitted by the light source and sample module 10 to the direction of the spherical collimating mirror 22. Specifically, the entrance slit 21 is a light-shielding plate with a slit, and the slit is aligned with the spherical collimating mirror 22 so that the target beam passes through the slit and illuminates the spherical collimating mirror 22.

[0063] The spherical collimating mirror 22 is a concave reflecting mirror, which faces the slit and is used to collimate the target beam into a parallel beam.

[0064] Specifically, the diffraction order of the echelle grating 23 is greater than 30, which enables the optical path structure to have high resolution in the same order of the spectrum.

[0065] like Figure 5 As shown, the shearing interference plate 24 includes a wedge-shaped optical glass plate. The top surface of the optical glass plate is a semi-transparent, semi-reflective first reflecting surface 231, and the bottom surface of the optical glass plate is a totally reflective second reflecting surface 232. The first reflecting surface 231 and the second reflecting surface 232 form a wedge-shaped angle between the optical glass plate and the plate. When light passes through the shearing interference plate 24, part of the light is reflected by the first reflecting surface 231, and another part of the light passes through the semi-transparent, semi-reflective first reflecting surface 231 and is then reflected by the second reflecting surface 232. The two reflected light rays can form an interference effect, which causes the light intensity to change periodically in the direction of the angle. Figure 5 As shown, interference fringes are generated at point a.

[0066] like Figure 4 and Figure 5 As shown, the cylindrical reflector 25 has a cylindrical concave mirror facing the shearing interference plate 24. The axis of the cylindrical concave mirror is parallel to the direction of interference, and is used to control the interfered light beam, such as... Figure 5 As shown, at point b, the interference fringes are focused in the direction of dispersion, maintained in the direction of interference, and reflected to the photoelectric sensor 31. The photoelectric sensor 31 can be a two-dimensional image receiving sensor. For example, the two-dimensional image receiving sensor can be a CMOS (Complementary Metal-Oxide-Semiconductor) type two-dimensional image receiving sensor, or it can be a CCD (charge-coupled device) type two-dimensional image receiving sensor. Of course, in the echelle grating spectrometer of this application embodiment, the two-dimensional image receiving sensor is not limited to CMOS type and CCD type.

[0067] In the embodiments of this application, the echelle grating spectrometer has the echelle grating 23 mounted vertically, such that its dispersion direction is... Figure 4 In the first direction shown, the shearing interference plate is located behind the echelle grating 23, and its wedge angle direction is perpendicular to the first direction of beam splitting of the grating, i.e. Figure 4 The second direction shown.

[0068] After cross-dispersion by the echelle grating 23 and the shearing interference plate, a cylindrical mirror projects the beam onto the sensor target surface. The cylindrical mirror is mounted parallel to the dispersion direction of the shearing interference plate, i.e., the second direction. This means it focuses only the beam along the direction of beam splitting by the echelle grating 23 (i.e., the first direction). Figure 5 As shown at point b, the light does not focus in the beam-splitting direction (i.e., the second direction) of the shearing interference plate 24.

[0069] Based on the principle of shear interference plates, such as Figure 5 As shown, it consists of two reflecting planes on the front and back of an optical glass plate. The first reflecting plane is a semi-transparent and semi-reflective surface. There is a small angle between the two reflecting planes, namely the wedge angle θ. The parallel beam is split into two beams by the first reflecting plane on the shearing interference plate 24 and reflected by the front and back reflecting planes respectively.

[0070] Because of the wedge angle between the two reflecting surfaces, the wavefronts W1 and W2 of the two reflected beams will have corresponding angles. If the incident light is monochromatic parallel light, after passing through the sheared interference plate, interference fringes will form in front of the cylindrical mirror. According to theoretical calculations, the intensity distribution of the interference light is sinusoidal, and the period T of the interference fringes is related to the wavelength of the beam and the tilt angle θ: T = λ / θ.

[0071] The cylindrical mirror will converge the light beam in the first direction, while keeping the second direction unchanged. The sensor target surface is located on the focal plane of the cylindrical mirror; therefore, the image on the sensor is a thin stripe of periodically distributed sinusoidal light intensity, oriented in the second direction. For example... Figure 5 As shown at point a, the position of the thin strip in the first direction is determined by the dispersion effect of the echelle grating 23.

[0072] Example 2

[0073] Figure 7 This is a schematic diagram of the electrical connection structure of a spectrometer provided in Embodiment 2 of this application, as shown below. Figure 7 As shown, a spectrometer includes: the aforementioned optical path structure, a signal processing module 32, and a display module 33. The signal processing module 32 is electrically connected to the photoelectric sensor 31 and the display module 33, respectively. The signal processing module 32 performs a spatial frequency domain Fourier transform on the electrical signal converted by the photoelectric sensor 31 to calculate the spectral characteristic information of the target beam, and displays it through the display module 33.

[0074] The spectrometer provided in this embodiment of the invention generates a target beam to be analyzed from a light source and sample module 10 in its optical path structure. After passing through an entrance slit 21 and a spherical collimating lens 22, a parallel beam is obtained. An echelle grating 23 disperses the parallel beam in a first direction. A shearing interference plate 24 interferes with the dispersed parallel beam in a second direction, perpendicular to the first direction. A cylindrical mirror 25 reflects the interfered beam and focuses it onto the photoelectric sensor 31 in the first direction. Compared to related technologies, the energy of light of a certain wavelength can be distributed along the interference direction, and is more evenly distributed among all pixels of the photoelectric sensor 31 in the interference direction, thereby improving the sensitivity of the photoelectric sensor 31 in measuring the beam. Furthermore, a signal processing module electrically connected to the photoelectric sensor 31 performs a spatial frequency domain Fourier transform on the electrical signal converted by the photoelectric sensor 31 to calculate the spectral characteristics of the target beam. This effectively eliminates dark current, averages noise, and improves the signal-to-noise ratio.

[0075] Therefore, this invention proposes a novel spectrometer that achieves cross-dispersion by using a shearing interference plate instead of a dispersive prism, such as... Figure 6As shown, the beam separation at wavelengths of 532nm and 354.7nm is not a direct positional separation, but rather a separation based on spatial frequency. Specifically, light of different wavelengths is divided into stripes with different periodicity, which are then read by a sensor and analyzed using a signal processing module. In practice, the signal processing module can be implemented using a computer. A Fourier transform is performed longitudinally to separate the spatial frequency spectrum and read its intensity. The advantage of this method is that the light energy is distributed longitudinally across the entire sensor target surface, ensuring full utilization of all sensor pixels. Simultaneously, the Fourier transform process averages the noise of each pixel, eliminating the influence of dark current, thereby significantly improving the overall signal-to-noise ratio. Through these innovations, the new echelle grating spectrometer achieves more efficient spectral separation and improved signal-to-noise ratio, further expanding the application areas of spectrometers.

[0076] Example 3

[0077] Figure 8 For a flowchart illustrating a spectral signal processing method provided in Embodiment 3 of this application, please refer to [link / reference]. Figure 8 As shown, a spectral signal processing method is applied to the signal processing module of the above-mentioned spectrometer, wherein the dispersion direction of the target beam is transverse to the photoelectric sensor, and the interference direction of the target beam is longitudinal to the photoelectric sensor.

[0078] The method includes:

[0079] S10. Obtain the pixel data of each column in the vertical direction of the photoelectric sensor. Each column of pixel data includes: pixel coordinate information and pixel brightness information.

[0080] After the target beam is dispersed in the first direction (x direction) by the echelle grating:

[0081] Therefore, on a given x-coordinate, there exists a series of discrete wavelengths: n~m represents the diffraction secondary range of the echelle grating, f is the focal length of the spectrometer, and d is the grating constant.

[0082] Without interference in the second direction (y-direction) via a shearing interferometer, the spectrum is a one-dimensional spectrum, and the signal value read by the sensor is...

[0083]

[0084] Here, A(λxi) represents the energy intensity of light at wavelength λxi. Each A(x) contains the superposition of energy values ​​of multiple wavelengths, and a one-dimensional spectrum cannot distinguish the energy values ​​of different sub-wavelengths individually.

[0085] When interference is achieved in the second direction by shearing an interference plate...

[0086] The dispersion of the echelle grating in the first direction and the interference fringes produced by the interference of the sheared interference plate in the second direction, the light intensity sensed by the photoelectric sensor can be expressed as:

[0087]

[0088] The formula before importing can be obtained

[0089]

[0090] This refers to the theoretical distribution of the target surface image of the photoelectric sensor under this method. In the implementation of the two-dimensional image receiving sensor, each pixel can be arranged into an array along a first direction and a second direction. A(u,v) corresponds to the photoelectric signal intensity data of the u-th pixel in the first direction and the v-th pixel in the second direction.

[0091] The signal processing module can read the pixel data of the two-dimensional image receiving sensor A(x,y), thereby obtaining the pixel brightness information x of each column of pixel data in the vertical direction of the photoelectric sensor:

[0092]

[0093] S20. Based on the pixel coordinate information and pixel brightness information of each column of pixel data, perform a spatial frequency domain Fourier transform on each column of pixel data in sequence to calculate the beam frequency domain sequence corresponding to each column of pixel data. The beam frequency domain sequence includes the corresponding data of beam frequency and beam intensity.

[0094] In performing a spatial frequency domain Fourier transform on a series of pixel data:

[0095]

[0096] Figure 9 for Figure 8 The diagram illustrating the frequency domain sequence function relationship of a beam corresponding to a column of pixel data in the spectral signal processing method shown is available in the original text. Figure 9 As shown in the equation, after spatial frequency domain transformation, a series of discrete peaks will appear on the frequency domain spectrum, with the peak positions being ki and their amplitudes representing the light wave intensity with wavelength λxi. Therefore, the separation of different secondary light waves is achieved, and their respective signal intensities can be read separately. In computer processing, since k is a known quantity, it is only necessary to obtain the signal intensity at positions ki,i = n to m on the frequency domain spectrum, which corresponds to the intensity of that secondary light wave.

[0097] In practice, by changing the x value and performing the above steps, the frequency domain sequence of the beam corresponding to each column of pixel data can be obtained.

[0098] S30. Statistically calculate the frequency domain sequence of the beams using the pixel data in each column, establish the corresponding data of all beam frequencies and all beam intensities, and generate the spectral characteristic information of the target beam.

[0099] The spectral signal processing method provided in this invention addresses the issue of sensor noise, such as dark current (DC component) or other noise, in the target beam sensed by the photoelectric sensor. Through a Fourier transform in the spatial frequency domain, the noise is located at a zero point in the frequency domain, thereby eliminating the noise and improving the accuracy of the target beam's spectral characteristics. Furthermore, the white noise in the photoelectric sensor, through a Fourier transform in the spatial frequency domain, is evenly distributed across the entire spectrum, significantly reducing its relative intensity to the target beam and improving the signal-to-noise ratio.

[0100] Example 4 (Verification Example)

[0101] In this verification embodiment, the spectrometer adopts the optical path structure described in Embodiment 1 above, wherein...

[0102] The echelle grating used is model GE2550-0863, with a grating constant of 79 lines per millimeter, a blaze angle of 63 degrees, and a dispersion of 5.75 nm / mrad. The spherical collimating mirror is a silver-plated spherical mirror with a focal length of f = 200 mm and a diameter of 2 inches. The cylindrical mirror has a focal length of f = 200 mm and dimensions of 52 x 30 mm. The wedge angle of the shearing interferometer is 10 arcseconds. The slit diameter of the entrance slit is 20 micrometers. The photoelectric sensor is a 1-inch x 1-inch cooled CMOS sensor from Hamamatsu Corporation, Japan, with 4096 x 4096 pixels. The light source and sample module use a mercury argon lamp, exhibiting a series of discrete emission spectra.

[0103] Figure 10 This is a schematic diagram of the imaging of the electrical sensor in the verification embodiment of this application. The sensor image obtained by experimental measurement is shown below. Figure 10 As shown. Figure 11 This application verifies the spectral characteristic information of a mercury-argon lamp lamp measured in the embodiment. After comparison, Figure 11 The spectral characteristics shown are consistent with those from authoritative laboratory databases.

[0104] Example 5

[0105] Figure 12 This is a schematic diagram of an electronic device provided in Embodiment 5 of this application. The electronic device provided in Embodiment 5 implements the spectral signal processing method described in the above embodiments. Please refer to... Figure 12 As shown.

[0106] An electronic device includes a processor 41, a communication interface 42, a memory 43, and a communication bus 44, wherein the processor 41, the communication interface 42, and the memory 43 communicate with each other through the communication bus 44.

[0107] Memory 43 is used to store computer programs;

[0108] When the processor 41 executes the program stored in the memory 43, it implements the above-described spectral signal processing method:

[0109] The vertical pixel data of the photoelectric sensor is obtained for each column, and each column of pixel data includes: pixel coordinate information and pixel brightness information;

[0110] Based on the pixel coordinate information and pixel brightness information of each column of pixel data, a spatial frequency domain Fourier transform is performed on each column of pixel data in sequence to calculate the beam frequency domain sequence corresponding to each column of pixel data. The beam frequency domain sequence includes the corresponding data of beam frequency and beam intensity.

[0111] By statistically analyzing the frequency domain data of the beams calculated from each column of pixel data, the corresponding data of all beam frequencies and all beam intensities are established, generating the spectral characteristic information of the target beam.

[0112] The communication bus mentioned in the above electronic devices can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0113] The communication interface is used for communication between the aforementioned electronic devices and other devices.

[0114] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0115] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0116] It should be noted that, in this document, 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.

[0117] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. The above descriptions are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. An optical path structure, characterized in that, include: The light source and sample module (10), the spectrometer module, and the photoelectric sensor (31) are included. The light source and sample module (10) are used to generate the target beam to be analyzed; The beam splitting module includes an entrance slit (21), a spherical collimating lens (22), an echelle grating (23), a shearing interference plate (24), and a cylindrical reflector (25); The entrance slit (21) is used to receive the target beam; The echelle grating (23) disperses the parallel beam obtained after passing through the entrance slit (21) and the spherical collimating lens (22) in the first direction; The shearing interference plate (24) is used to interfere the parallel beam after the dispersion of the echelle grating (23) in a second direction, which is perpendicular to the first direction. The cylindrical mirror (25) is used to reflect the interfered light beam and focus it onto the photoelectric sensor (31) in the first direction; The photoelectric sensor (31) is used to convert the received target beam from an optical signal into an electrical signal and send it to the signal processing module electrically connected to it, so that the signal processing module can perform a spatial frequency domain Fourier transform based on the converted electrical signal and calculate the spectral feature information of the target beam.

2. The optical path structure according to claim 1, characterized in that, The light source and sample module (10), the entrance slit (21), and the spherical collimating mirror (22) are arranged on the same optical axis.

3. The optical path structure according to claim 1, characterized in that, The entrance slit (21) is a light-shielding plate with a slit, and the slit is aligned with the spherical collimating lens (22) so that the target beam passes through the slit and illuminates the spherical collimating lens (22); The spherical collimating mirror (22) is a concave reflecting mirror, which faces the slit and is used to collimate the target beam into a parallel beam.

4. The optical path structure according to claim 1, characterized in that, The diffraction order of the echelle grating (23) is greater than 30.

5. The optical path structure according to claim 1, characterized in that, The shearing interference plate (24) includes: a wedge-shaped optical glass plate, the top surface of which is a semi-transparent and semi-reflective first reflective surface (231), and the bottom surface of which is a total reflective second reflective surface (232), the first reflective surface (231) and the second reflective surface (232) forming a wedge-shaped angle of the optical glass plate.

6. The optical path structure according to claim 1, characterized in that, The cylindrical reflector (25) has a cylindrical concave mirror facing the shearing interference plate (24). The axis of the cylindrical concave mirror is parallel to the direction of interference, and is used to focus the beam after interference in the direction of dispersion, maintain it in the direction of interference, and reflect it to the photoelectric sensor (31).

7. The optical path structure according to claim 1, characterized in that, The photoelectric sensor (31) is a two-dimensional image receiving sensor.

8. A spectrometer, characterized in that, include: The optical path structure, signal processing module (32), and display module (33) as described in any one of claims 1 to 7; The signal processing module (32) is electrically connected to the photoelectric sensor (31) and the display module (33) respectively; The signal processing module (32) performs a spatial frequency domain Fourier transform on the electrical signal converted by the photoelectric sensor (31), calculates the spectral characteristic information of the target beam, and displays it through the display module (33).

9. A spectral signal processing method, characterized in that, The signal processing module applied in the spectrometer of claim 8, wherein the dispersion direction of the target beam is transverse to the photoelectric sensor (31), and the interference direction of the target beam is longitudinal to the photoelectric sensor (31); the method includes: The vertical pixel data of the photoelectric sensor (31) is obtained, and each column of pixel data includes: pixel coordinate information and pixel brightness information; Based on the pixel coordinate information and pixel brightness information of each column of pixel data, a spatial frequency domain Fourier transform is performed on each column of pixel data in sequence to calculate the beam frequency domain sequence corresponding to each column of pixel data. The beam frequency domain sequence includes the corresponding data of beam frequency and beam intensity. By statistically analyzing the frequency domain data of the beams calculated from each column of pixel data, the corresponding data of all beam frequencies and all beam intensities are established, generating the spectral characteristic information of the target beam.

10. An electronic device, characterized in that, It includes a processor (41), a communication interface (42), a memory (43), and a communication bus (44), wherein the processor (41), the communication interface (42), and the memory (43) communicate with each other through the communication bus (44); Memory (43) is used to store computer programs; The processor (41) is used to implement the spectral signal processing method of claim 9 when executing the program stored in the memory (43).

Images