Non-contact on-line near infrared spectrum analyzer and analysis method

Abstract

The invention relates to the technical field of non-contact near-infrared spectrum analysis, and discloses a non-contact online near-infrared spectrum analyzer and an analysis method.A light source module adopts a main light source and a plurality of auxiliary light sources with characteristic absorption peaks, so that enhanced analysis based on characteristic wavelength direct response can be realized; the inherent limitations of absorption peak overlapping and baseline drift in a traditional diffuse reflection spectrum are overcome, the prediction precision is improved, and the measurement effect is optimized. The receiving module adopts a plurality of optical fibers, the sampling ends of the plurality of optical fibers are uniformly distributed along the circumferential direction, the sampling ends of the plurality of optical fibers are distributed up and down in the direction vertical to the sample, and the detection ends of the optical fibers are uniformly distributed along the length direction of the slit of the spectrometer, so that the light collection efficiency is greatly improved, and the utilization efficiency of light source energy is maximized; and diffuse reflection / scattered light signals returned from the sample are efficiently captured, and the interference of environmental stray light is effectively isolated and weakened. In addition, a linear method and a nonlinear method are used in a mixed mode, and higher prediction precision is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of non-contact near-infrared spectroscopy analysis, in particular to a non-contact online near-infrared spectroscopy analyzer and analysis method. BACKGROUND

[0002] Near-infrared spectroscopy analysis technology has been widely used in biomedical, pharmaceutical, agricultural and food industries due to its advantages of rapidity and non-destructiveness. However, there are still deficiencies in non-contact measurement of online near-infrared spectroscopy for increasing demands such as in-vivo tissue monitoring, online quality control of pharmaceuticals, and industrial online analysis.

[0003] In a non-contact mode, the light energy emitted by the light source is rapidly dissipated in free space. The light flux irradiated to the sample surface is limited, and the effective diffuse reflection / scattering signal generated is even weaker. Traditional parallel light irradiation or simple focusing light path is difficult to efficiently collect these weak scattered light, resulting in low signal-to-noise ratio of the final acquired spectrum, which is difficult to meet the demand of high-precision quantitative analysis, leading to low light energy utilization and insufficient signal-to-noise ratio.

[0004] In addition, in non-contact measurement, there is a certain distance between the optical fiber and the sample surface, which will cause a sharp change in the irradiation spot area and the collection light path efficiency in actual application, causing a large drift in signal intensity, seriously affecting the repeatability and reliability of the measurement results.

[0005] The open non-contact measurement environment is easily disturbed by environmental light, further degrading the already weak effective signal, and the measurement results are seriously disturbed by environmental stray light. For example, in tobacco detection, the tobacco sample is placed on a conveyor belt, and the analyzer is located above the conveyor belt for detection, which is easily disturbed by the environment. SUMMARY

[0006] The purpose of the present application is to provide a non-contact online near-infrared spectroscopy analyzer and analysis method, which can efficiently suppress stray light and effectively improve the signal-to-noise ratio, thereby improving the measurement reliability and repeatability.

[0007] In order to achieve the above-mentioned purpose, the present application provides the following scheme: In a first aspect, the present application provides a non-contact online near-infrared spectroscopy analyzer, comprising: a light source module comprising a main light source, a plurality of auxiliary light sources, a wavelength calibration light source, and a light source switching mirror; the main light source is used to provide near-infrared light for irradiating a sample; the auxiliary light source is used to emit light of a specific wavelength range to the sample to improve the signal intensity at the characteristic absorption peak of the component in the sample; the wavelength calibration light source is used to emit reference light of a known characteristic wavelength, and the reference light is used for wavelength calibration; the light source switching mirror is used to guide the auxiliary light source and / or the wavelength calibration light source to the light path module; a light path module for guiding the light emitted by the main light source and / or the auxiliary light source and / or the wavelength calibration light source to the sample, and / or shaping the light emitted by the main light source and / or the auxiliary light source and / or the wavelength calibration light source; a calibration plate between the light path module and the sample for background calibration and wavelength calibration; a receiving module comprising a plurality of optical fibers, the optical fibers having sampling ends and detection ends, the sampling ends being used to collect optical signals, and the detection ends being coupled to a spectrometer and used to conduct the optical signals to the spectrometer, the sampling ends of the plurality of optical fibers being uniformly distributed in a circumferential direction, and each of the sampling ends of the optical fibers having a different height position relative to the sampling ends of the other optical fibers in a direction perpendicular to the sample, and the detection ends of the plurality of optical fibers being uniformly arranged along a length direction of a slit of the spectrometer; a spectrometer for receiving the optical signals conducted by the optical fibers and generating corresponding spectral data; a data processing and analysis module for processing and analyzing the spectral data.

[0008] In a second aspect, the present application provides a non-contact online near-infrared spectral analysis method based on the above-described analyzer, comprising: S100, only turn on the main light source, the light emitted by the main light source forms a transmission cone-shaped light path to irradiate the sample through the light path module, the sampling ends of the optical fibers receive the optical signals carrying the component information of the sample generated under the irradiation of the light source module, form a receiving cone-shaped light path, and the receiving cone-shaped light paths of the plurality of optical fibers form a three-dimensional intersection sampling area in the vertical direction of the sample; the transmission cone-shaped light path and the receiving cone-shaped light path intersect in the vertical direction of the sample, so that the optical signals generated after the light emitted by the light source module interacts with the sample are captured by the optical fibers and conducted to the spectrometer, and the spectrometer generates basic light intensity data; S200, only turn on the selected auxiliary light source to irradiate the sample, and obtain corresponding supplementary light intensity data; S300, place the calibration plate in the transmission cone-shaped light path to shield the sample, only turn on the main light source, the spectrometer receives the optical signals reflected by the calibration plate, and generates corresponding first calibration light intensity data; turn off the main light source, only turn on the auxiliary light source used in step S200 to irradiate the calibration plate, and obtain corresponding second calibration light intensity data; S400, only turn on the wavelength calibration light source, the spectrometer receives the optical signals reflected by the calibration plate, and generates corresponding third calibration light intensity data; S500, the data processing and analysis module is generated to the spectrometer basis light intensity data, the supplementary light intensity data, the first calibration light intensity data, the second calibration light intensity data and the third calibration light intensity data are preprocessed, obtain the preprocessed sample spectrum data, then based on the preset algorithm is calculated to the preprocessed sample spectrum data and the corresponding component content value is output.

[0009] Compared with the prior art, the present application has the following advantages: The light source module of the present application adopts a main light source and several auxiliary light sources with characteristic absorption peaks, which can realize enhanced analysis based on direct response of characteristic wavelengths, overcome the inherent limitations of overlapping absorption peaks and baseline drift in traditional diffuse reflectance spectroscopy, and significantly improve the prediction accuracy, robustness and discrimination ability of similar materials of the correction model, thereby optimizing the measurement effect. The receiving module of the present application adopts multiple optical fibers, the sampling ends of which are uniformly distributed in the circumferential direction, and the sampling ends of the multiple optical fibers are distributed in height in the direction perpendicular to the sample. The detection ends of the optical fibers are uniformly arranged along the length direction of the slit of the spectrometer. Within a certain axial distance variation range, because the sampling ends of optical fibers of different heights receive different ranges of diffuse reflection light, the depth of field of the received light is increased, which enables the instrument to have better adaptability to samples at different distances. The structure is equivalent to constructing an "optical funnel" in space, which can collect scattered light from the sample from multiple angles and a large range, greatly improving the light collection efficiency, maximizing the utilization efficiency of light source energy, and efficiently capturing the diffuse reflection / scattering light signal returned from the sample. At the same time, it realizes the "self-adaptive" tolerance at the physical level without the need for complex active feedback mechanisms. Moreover, the circumferential high-low arrangement of the multiple optical fibers enables them to mainly receive signal light from the sample detection area, while naturally shielding environmental stray light from other angles, forming a spatial filtering effect, effectively isolating and weakening the interference of environmental stray light, forming a stray light suppression mechanism, and effectively improving the signal-to-noise ratio. In addition, the present application uses a combination of linear and nonlinear, which has higher prediction accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is the optical path diagram of the non-contact online near-infrared spectrum analyzer of the embodiment of the present application.

[0011] Figure 2 is the tobacco sample spectrum diagram of the second embodiment of the present application.

[0012] Figure 3 is the acetic acid fiber sample spectrum diagram of the second embodiment of the present application.

[0013] Figure 4 is the flowchart of the non-contact online near-infrared spectrum analysis method of the embodiment of the present application.

[0014] In the figure, 1 - main light source; 2 - auxiliary light source; 3 - wavelength calibration light source; 4 - light source switching mirror; 5 - calibration plate; 6 - optical fiber; 7 - spectrometer; 8 - collimation unit; 801 - off-axis parabolic mirror; 802 - plano-convex lens; 803 - light extinction lens barrel; 9 - mirror; 10 - protective window piece. DETAILED DESCRIPTION

[0015] The specific embodiments of the present application will be further described in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but are not used to limit the scope of the present application.

[0016] In the description of the present application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0017] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0018] In addition, in the description of the present application, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0019] Example 1 As Figure 1 shown, the non-contact online near-infrared spectrum analyzer of the preferred embodiment of the present application comprises: The light source module comprises a main light source 1, a plurality of auxiliary light sources 2, a wavelength calibration light source 3 and a light source switching mirror 4; the main light source 1 is used to provide near-infrared light to irradiate the sample; the auxiliary light source 2 is used to emit light of a specific wavelength range to the sample to improve the signal intensity at the characteristic absorption peak of the component in the sample; the wavelength calibration light source 3 is used to emit reference light of a known characteristic wavelength, and the reference light is used for wavelength calibration; the light source switching mirror 4 is used to guide the auxiliary light source 2 and / or the wavelength calibration light source 3 to the light path module; a light path module for guiding the light emitted by the main light source 1 and / or the auxiliary light source 2 and / or the wavelength calibration light source 3 onto the sample, and / or shaping the light emitted by the main light source 1 and / or the auxiliary light source 2 and / or the wavelength calibration light source 3; a calibration plate 5 located between the light path module and the sample for background calibration and wavelength calibration; the calibration plate 5 is rotated between or removed from the light path module and the sample; a receiving module including a plurality of optical fibers 6, the optical fibers 6 having sampling ends and detection ends, the sampling ends being used for collecting light signals, and the detection ends being coupled to a spectrometer 7 and used for conducting the light signals to the spectrometer 7; the sampling ends of the plurality of optical fibers 6 are uniformly distributed in a circumferential direction, and each sampling end of the optical fibers 6 has a different height position relative to the sampling ends of the other optical fibers 6 in a direction perpendicular to the sample, and the detection ends of the plurality of optical fibers 6 are uniformly arranged along a length direction of a slit of the spectrometer 7; the spectrometer 7 is used for receiving the light signals conducted by the optical fibers 6 and generating corresponding spectral data; a data processing and analysis module, which is used for processing and analyzing the spectral data.

[0020] The light source module of the embodiment adopts the main light source 1 and a plurality of auxiliary light sources 2 with characteristic absorption peaks, and can realize enhanced analysis based on direct response of characteristic wavelengths, overcome the inherent limitations of overlapping absorption peaks and baseline drift in traditional diffuse reflectance spectroscopy, and thus significantly improve the prediction accuracy, robustness and distinguishing ability of similar materials of the correction model, so as to optimize the measurement effect. The receiving module of the embodiment adopts a plurality of optical fibers 6, the sampling ends of the plurality of optical fibers 6 are uniformly distributed in a circumferential direction, and the sampling ends of the plurality of optical fibers 6 have a high-low distribution in a direction perpendicular to the sample, and the detection ends of the optical fibers 6 are uniformly arranged along a length direction of a slit of the spectrometer 7. Within a certain axial distance variation range, because the sampling ends of the optical fibers 6 at different heights receive different ranges of diffuse reflection light, the depth of field of the received light is increased, the instrument has better adaptability to samples at different distances, and this structure is equivalent to constructing an "optical funnel" in space, which can collect scattered light from the sample from multiple angles and a large range, greatly improve the light collection efficiency, realize the maximum utilization efficiency of light source energy, and efficiently capture the diffuse reflection / scattering light signals returned from the sample, and at the same time realize the "self-adaptive" tolerance at the physical level without the need for complex active feedback mechanisms. Moreover, the circumferential high-low arrangement of the plurality of optical fibers 6 enables the optical fibers 6 to mainly receive signal light from the sample detection area, and has a natural shielding effect on environmental stray light at other angles, forming a spatial filtering effect, effectively isolating and weakening the interference of environmental stray light, forming a stray light suppression mechanism, and effectively improving the signal-to-noise ratio.

[0021] In some embodiments, the light path module comprises a collimating unit 8 for collimating and / or converging the light emitted by the light source module; and a mirror 9 located at the geometric center surrounded by the sampling ends of the plurality of optical fibers 6, the mirror 9 being configured to direct the light emitted by the light source module to the sample. The light emitted by the light source module is irradiated on the sample after passing through the collimating unit 8 and the mirror 9. By using the collimating unit 8, the divergent and disordered light energy is converted into a concentrated and controllable light beam, greatly improving the light energy utilization and signal quality, and fundamentally ensuring the high repeatability, stability and reliability of the analysis model. By using the mirror 9, the overall device is small. In addition, in addition to the positions of the light source module and the light path module shown in the figure, other positions can also use the mirror 9. The mirror 9 is inclined, and the inclination angle of the mirror 9 in the embodiment is 45°. It should be pointed out that the inclination angle of the mirror 9 in the present application is not limited to only 45°. When the inclination angle of the mirror 9 is other angles (such as 30°, 60°, etc.), the included angle between the optical fiber 6 and the mirror 9 also changes accordingly, and the changed angle is determined by the presented light spot. Figure 1

[0022] Further, the collimating unit 8 can move in the direction close to or away from the light source module. By moving the collimating unit 8, the distance between the collimating unit 8 and the light source module can be changed, so as to control the size of the light spot emitted by the light source module. Optionally, the collimating unit 8 comprises one or more than one lens, and therefore, the number of lenses is not limited and the shape is also not limited. When the collimating unit 8 comprises more than one lens, the adjacent two lenses can be close to or away from each other, so as to adjust the size, energy density, etc. of the irradiation light spot. In the embodiment, the collimating unit 8 comprises two lenses, which are a aspherical lens and a plano-convex lens 802, and the aspherical lens is located between the light source module and the plano-convex lens 802. The combination of the aspherical lens and the light extinction lens barrel 803 is the core basis of the analyzer device, and the important purpose is to realize a high-quality controllable parallel light beam, reduce the stray light of the analyzer device, improve the light spot shape and uniformity irradiated on the sample, and further improve the repeatability and accuracy of the analyzer device. Optionally, the aspherical lens can be a double-convex lens.

[0023] ​In some other embodiments, the analyzer further comprises a protective window sheet 10 arranged between the light path module and the sample, the protective window sheet 10 is used to isolate the internal environment of the detection analyzer from the external environment, the light emitted by the light source module is guided by the light path module and transmitted by the protective window sheet 10 before irradiating on the sample, wherein the protective window sheet 10 is arranged obliquely to reduce the specular reflection of the light source module. The protective window sheet 10 is a flat lens. The analyzer device has a shell, the shell is provided with a window, and the protective window sheet 10 is arranged at the window. The near-infrared light emitted by the light source module is finally irradiated on the sample after being transmitted by the protective window sheet 10. The protective window sheet 10 is a medium for isolating the internal environment of the device from the external environment. The protective window sheet 10 is not placed horizontally but has a certain inclination angle. The main reason is that the horizontal placement may cause errors in the collection of the light spot due to the specular reflection of light. The inclined placement can reflect the reflected light out of the collection range.

[0024] In this embodiment, four optical fibers 6 are used, and the mirror 9 is located at the geometric center surrounded by the four optical fibers 6. It should be pointed out that the number of optical fibers 6 is not limited, and the number is as large as possible under the condition of considering the signal collection intensity and the slit height of the spectrometer.

[0025] In this embodiment, the light source module emits near-infrared light, which is focused into a specific range of light by the shaping unit 8. After the reflected light passes through the protective window sheet 10, it irradiates on the sample. This light path is a transmission cone-shaped light path. At the same time, the shaping unit 8 can move linearly left and right in the horizontal direction to control the size of the light spot of the transmission light path, so that the light spot irradiating on the sample is only slightly larger than the sample, and the light intensity in the range of the sample irradiated by the light source module approaches the maximum, thereby constructing an independent transmission light cone. The light irradiating on the sample is collected by the optical fibers 6 and then transmitted to the photosensitive elements inside the spectrometer 7 after being collected. This light path is a receiving cone-shaped light path. At the same time, the optical fibers 6 can move linearly up and down in the direction perpendicular to the sample to control the size of the light spot of the receiving light path, so that the size of the light spot receiving the sample is only slightly smaller than the light spot of the transmission light path, and the light spot of the receiving light path and the light spot of the transmission light path can infinitely approach the sample range, and the two intersect in the space of the sample to form a three-dimensional intersection sampling area. This is that the transmission cone-shaped light path and the receiving cone-shaped light path can realize cooperative action in use, thereby constructing a double-cone-shaped cooperative light path device. Optionally, the range of sample distribution, the irradiation area formed by the light source module, and the receiving area formed by all optical fibers 6 infinitely approach each other, wherein the range of sample distribution accounts for less than 90-95% of the irradiation area formed by the light source module, and the receiving area formed by all optical fibers 6 accounts for 90%-98% of the irradiation area formed by the light source module.

[0026] Embodiment two The difference between the present embodiment and Embodiment One is that the shaping unit 8 of the present embodiment is different from that of Embodiment One, and the analyzer is further described based on Embodiment One.

[0027] In the present embodiment, the shaping unit 8 comprises an off-axis parabolic mirror 801, a plano-convex lens 802 and an extinction lens barrel 803, the off-axis parabolic mirror 801 and the plano-convex lens 802 are installed in the extinction lens barrel 803, and the light emitted by the light source module is sequentially irradiated on the sample through the off-axis parabolic mirror 801, the plano-convex lens 802 and the mirror 9. The off-axis parabolic mirror 801 and the plano-convex lens 802 are used to realize reflection achromatism and refractive flexible regulation, so as to obtain better light spot quality and light source uniformity. The off-axis parabolic mirror 801 collimates and focuses the light beam, first realizes perfect light beam control of wide spectral range and without aberration, and fundamentally eliminates dispersion. The plano-convex lens 802 is used as a subsequent fine adjustment component, and locally shapes, finely focuses or compensates the light beam, so as to finally realize higher precision and flexibility of light path regulation ability on the premise of ensuring full-band spectral fidelity. The light source module is located at the focal point of the parent parabolic surface of the off-axis parabolic mirror 801, and the light emitted by the light source module forms a non-occluded parallel light beam after being reflected by the off-axis mirror surface area.

[0028] As for the extinction lens barrel 803, an extinction lens barrel 803 with an extinction structure and / or an extinction material can be used. In terms of structure, the extinction structure refers to a geometric structure arranged in the inner wall or internal light path of the lens barrel for suppressing the reflection and propagation of stray light, which reduces the possibility of stray light reaching the imaging surface by changing the light incidence angle, increasing the light path occlusion or prolonging the non-imaging light path. For example, the extinction structure can include but is not limited to inner wall grooves, light blocking rings, multi-stage steps or rough surfaces formed by sandblasting; in terms of material, the extinction material refers to a material with low reflectivity or high light absorption performance used to constitute the lens barrel body or its surface treatment layer, which suppresses stray light by reducing the reflection of light in the inner wall of the lens barrel; such materials can include but are not limited to: black non-reflective coating (such as black chromium, black nickel, carbon nanotube coating or Acktar metal black film) coated on the surface of a metal substrate (such as aluminum alloy, stainless steel), directly injection molded using engineering plastics (such as carbon black added polyether ether ketone PEEK or polysulfone PSU) with high light absorption performance, or forming a low reflectivity surface layer on metal and plastic substrates through anodizing, chemical deposition, physical vapor deposition (PVD) and other processes, and commercially available high absorption extinction paint (such as Nextel Velvet Coating, Aeroglaze Z306, etc.) can also be used for spraying treatment.

[0029] In some embodiments, the light source switching mirror 4 is movably arranged between the main light source 1 and the optical path module, so that the light source switching mirror 4 is located in or removed from the light path of the main light source 1. When the light source switching mirror 4 is not located in the light path of the main light source 1, the light emitted by the main light source 1 is guided to the sample through the optical path module. When the main light source 1 is turned off, the light source switching mirror 4 is located in the light path of the main light source 1, and the light emitted by the auxiliary light source 2 and / or the wavelength calibration light source 3 is guided to the optical path module through the light source switching mirror 4 and then guided to the sample through the optical path module. Specifically, the light source switching mirror 4 is located in or removed from the light path of the main light source 1 by rotating.

[0030] In other embodiments, the light source switching mirror 4 is a half-reflective and half-transmissive mirror. The light source switching mirror 4 has a transmission side and a reflection side arranged opposite to each other. The transmission side faces the main light source 1, and the reflection side faces the auxiliary light source 2 and the wavelength calibration light source 3. The light source switching mirror 4 can be always in the light path, and the switching of multiple light sources is achieved by electric control. The opposite sides of the light source switching mirror 4 are coated with an anti-reflection film and an anti-reflection film respectively to form the transmission side and the reflection side. The transmission side can effectively reduce the reflection loss of the main light source 1, so that most of the light emitted by the main light source 1 can be transmitted through the mirror, greatly improving the energy utilization efficiency of the light path. The reflection side can enhance the reflection ability of the auxiliary light source 2 and the wavelength calibration light source 3, so that most of the light emitted by the light source can be reflected and turned, achieving high-efficiency light path beam splitting or turning, while unnecessary transmission loss is suppressed.

[0031] In addition, in the present embodiment, the auxiliary light source 2 is arranged as three, and one of the auxiliary light sources 2 is used to improve the signal intensity at the characteristic absorption peak of water. The light source switching mirror 4 is used for light source switching, and different light sources enter the shaping unit 8 by switching the light source switching mirror 4. It should be pointed out that the auxiliary light source 2 is used to emit light of a specific wavelength range to the sample to improve the signal intensity at the characteristic absorption peak of the component in the sample. The selection of the auxiliary light source 2 is based on the component of the sample to be detected. If the protein, fat, etc. of the sample needs to be detected, the auxiliary light source 2 that can improve the signal intensity at the characteristic absorption peak of the protein and fat is selected. In the present embodiment, the moisture of tobacco and acetate fiber is detected, so the auxiliary light source 2 that can improve the signal intensity at the characteristic absorption peak of the moisture is selected. Alternatively, the auxiliary light source 2 that can improve the signal intensity at the characteristic absorption peak of the moisture near 1450 nm is selected in the present embodiment, wherein the near 1450 nm is 1450 ± 20 nm.

[0032] In addition, the working wavelength range of the main light source 1 is 400-2500 nm, that is, the wavelength of the light emitted by the main light source 1 covers a wide range of 400-2500 nm. The auxiliary light source 2 can use a narrow-band light source such as an LED or an LD. The wavelength calibration light source 3 can be a xenon lamp, an LED or an SLD laser diode.

[0033] In the embodiment, the light emitted by the main light source 1 and / or the auxiliary light source 2 and / or the wavelength calibration light source 3 is collimated by the off-axis parabolic mirror 801 to form a high-quality parallel light beam, and then is transmitted to the mirror 9 after being converged by the plano-convex lens 802. The reflected light beam is reflected by the mirror 9 and then is irradiated on the sample after passing through the protection window sheet 10. Meanwhile, the plano-convex lens 802 can be linearly moved left and right in the horizontal direction to control the spot size of the light path, so that the spot size on the sample is only slightly larger than the sample, and the light intensity in the range of the sample irradiated by the light source module approaches the maximum, thereby constructing an independent emission cone. The light irradiated on the sample is collected by the optical fiber 6, and then is transmitted to the photosensitive element in the spectrometer 7 after being collected, and the light path is a receiving cone-shaped light path. Meanwhile, the optical fiber 6 can be linearly moved up and down in the direction perpendicular to the sample to control the spot size of the receiving light path, so that the spot size of the received sample is only slightly smaller than the spot size of the emission light path, and the spot size of the receiving light path and the spot size of the emission light path can infinitely approach the sample range, and the two are converged in the space of the sample to form a three-dimensional cross-sampling area. This is that the emission cone-shaped light path and the receiving cone-shaped light path can realize the cooperative effect in use, thereby constructing a double-cone-shaped cooperative light path device. Optionally, the sample distribution range, the irradiation area formed by the light source module, and the receiving area formed by all the optical fibers 6 infinitely approach each other, wherein the sample distribution range accounts for less than 90-95% of the irradiation area formed by the light source module, and the receiving area formed by all the optical fibers 6 accounts for 90%-98% of the irradiation area formed by the light source module.

[0034] The data processing and analysis module is configured to process and analyze the spectral data generated by the spectrometer 7. In the detection, only the main light source 1 is turned on, and the light emitted by the main light source 1 forms a transmission cone-shaped light path through the light path module and irradiates on the sample. The sampling end of the optical fiber 6 receives the light signal carrying the component information of the sample under the irradiation of the light source module, forms a receiving cone-shaped light path, and the receiving cone-shaped light paths of the plurality of optical fibers 6 form a three-dimensional cross-sampling area in the vertical direction of the sample. The transmission cone-shaped light path and the receiving cone-shaped light path intersect in the vertical direction of the sample, so that the light signal generated after the light emitted by the light source module interacts with the sample is captured by the optical fiber 6 and conducted to the spectrometer 7, and the spectrometer 7 generates basic light intensity data. Only the selected auxiliary light source 2 is turned on to irradiate the sample, and corresponding supplementary light intensity data is obtained. The calibration plate 5 is placed in the transmission cone-shaped light path to shield the sample, only the main light source 1 is turned on to irradiate the calibration plate 5, the spectrometer 7 receives the light signal reflected by the calibration plate 5, and corresponding first calibration light intensity data is generated. The main light source 1 is turned off, and only the selected auxiliary light source 2 is turned on to irradiate the calibration plate 5, and corresponding second calibration light intensity data is obtained. Only the wavelength calibration light source 3 is turned on, and the spectrometer 7 receives the light signal reflected by the calibration plate 5 and generates corresponding third calibration light intensity data. The data processing and analysis module pre-processes the basic light intensity data, the supplementary light intensity data, the first calibration light intensity data, the second calibration light intensity data and the third calibration light intensity data generated by the spectrometer 7 to obtain sample spectral data, and then calculates and outputs the corresponding component content value based on the preset algorithm.

[0035] The preprocessing includes background calibration, wavelength calibration and spectrum combination. The background calibration includes: The first calibration light intensity data is used for background calibration of the basic light intensity data to obtain background-calibrated basic spectral data, and the second calibration light intensity data is used for background calibration of the supplementary light intensity data to obtain background-calibrated supplementary spectral data.

[0036] The wavelength calibration includes: The third calibration light intensity data is used to generate third calibration spectral data, the third calibration spectral data is compared with a preset mapping relationship to determine a current wavelength calibration deviation, the preset mapping relationship is updated based on the wavelength calibration deviation to obtain updated wavelength calibration parameters, the background-calibrated basic spectral data is wavelength-corrected by using the updated wavelength calibration parameters to output wavelength-calibrated basic spectral data, and the background-calibrated supplementary spectral data is wavelength-corrected by using the updated wavelength calibration parameters to output wavelength-calibrated supplementary spectral data. The preset mapping relationship is used to represent the correlation between each sampling unit of the detector of the spectrometer 7 and its corresponding physical wavelength, such as the function relationship between the pixel index and the wavelength (nm). The mapping relationship can be a linear or nonlinear model, which is obtained by standard light source calibration at the factory, and can be dynamically updated by the wavelength calibration light source 3 during use.

[0037] The spectral combination includes: The sample spectral data is generated based on the wavelength-calibrated base spectral data and the wavelength-calibrated supplementary spectral data. In this embodiment, the spectral combination is to accumulate the wavelength-calibrated base spectral data and the wavelength-calibrated supplementary spectral data to obtain the final sample spectral data. It should be pointed out that the wavelength-calibrated base spectral data and the wavelength-calibrated supplementary spectral data can also be averaged or weighted summed.

[0038] This embodiment mainly measures the moisture of the sample. In the foregoing measurement, the auxiliary light source 2 used is to enhance the signal intensity at the characteristic absorption peak of the moisture, specifically the auxiliary light source 2 for enhancing the signal intensity near the characteristic absorption peak 1450 nm. The preprocessing also includes further processing the sample spectral data obtained by the spectral combination, including processing the sample spectral data according to the water content of the sample. According to the water content of the sample based on the wavelength-calibrated supplementary spectral data, if the water content of the sample is greater than a threshold, the water content of the sample is high, and if the water content of the sample is lower than the threshold, the water content is low.

[0039] If the water content of the sample is high, the sample spectral data is subjected to Savitzky-Golay smoothing filtering to suppress high-frequency noise to obtain smoothed spectral data; the asymmetric least squares method ALS is used to perform baseline correction on the smoothed spectral data to obtain baseline-corrected spectral data; the standard normal variate transformation SNV is performed on the baseline-corrected spectrum to simultaneously correct the scattering effect caused by the difference in the physical state of the sample and the amplitude fluctuation caused by the moisture to obtain transformed spectral data; the transformed spectral data is divided into a low waveband and a high waveband, and the high waveband is subjected to a second-order Savitzky-Golay derivative processing to enhance the component resolution capability to obtain high waveband spectral data; the low waveband is subjected to Savitzky-Golay smoothing filtering processing to obtain low waveband spectral data; the high waveband spectral data and the low waveband spectral data are spliced to obtain spliced spectral data, and the spliced spectral data is subjected to mean centering to obtain the preprocessed sample spectral data.

[0040] If the sample has low water content, the sample spectral data is subjected to Savitzky-Golay smoothing filtering to suppress high-frequency noise to obtain smoothed spectral data; the smoothed spectral data is subjected to baseline correction by asymmetric least squares (ALS) to obtain baseline-corrected spectral data; the baseline-corrected spectral data is subjected to standard normal variate (SNV) transformation to simultaneously correct the scattering effect caused by the difference in the physical state of the sample and the amplitude fluctuation caused by water to obtain transformed spectral data; the transformed spectral data is subjected to continuum removal (CR) processing, wherein the wavelength band where the characteristic absorption peak is located is avoided during envelope fitting to obtain removed spectral data; the removed spectral data is subjected to mean centering to obtain the pretreated sample spectral data.

[0041] The data processing and analysis module analyzes the pretreated sample spectral data, calculates the pretreated sample spectral data based on a preset algorithm, and outputs the corresponding component content value. The preset algorithm includes a correction model, which is established as follows: a set of representative calibration set samples is prepared, and the spectral data thereof is collected by the analyzer of the present embodiment; the concentration or property reference value of the calibration set samples is determined by a standard method; the pretreated sample spectral data is associated with the reference value, and a correction model between the spectral data and the reference value is established by using a modeling algorithm. The correction model of the present embodiment includes a linear regression model and a nonlinear regression model. The pretreated sample spectral data is input into the linear regression model to obtain a first component content value; the pretreated spectral data is input into the nonlinear regression model to obtain a second component content value; and the first component content value and the second component content value are weighted and fused to obtain the final component content value.

[0042] In an embodiment, tobacco is selected as the sample to be detected, and 210 representative tobacco samples of different sources are collected. When detecting, the distance between the tobacco sample and the protective window sheet 10 is 200-300 mm. The component content value of the 210 tobacco samples is detected, the spectral data of the 210 tobacco samples is collected by the spectrometer 7 respectively, and the spectral graph output after the spectral data of the tobacco sample is pretreated is as shown in FIG. 6. Figure 2 The standard chemical analysis method is used to collect each tobacco sample for 3 times, and the average value thereof is taken as the reference value of the sample.

[0043] The spectral data of the tobacco sample is subjected to the pretreatment method for samples with high water content to obtain pretreated tobacco sample spectral data. The pretreated tobacco sample spectral data and the reference value are used to train and verify the correction model established by using a multivariate correction algorithm. The performance of the comprehensive correction model of the present embodiment is shown in Table 1.

[0044] Table 1: Performance of tobacco sample component content value detection

[0045] In another embodiment, acetate fiber was selected as the sample to be tested. Fifty-six representative acetate fiber samples from different sources were collected. Using the analyzer of this embodiment, the distance between the acetate fiber sample and the protective window 10 was 200-300 mm during detection. The component content of these 56 acetate fiber samples was determined. Spectral data of these 56 acetate fiber samples were acquired by spectrometer 7. The preprocessed spectrograms of the acetate fiber sample spectral data are shown below. Figure 3 As shown in the figure. Standard chemical analysis methods were used to collect samples three times for each acetate fiber sample, and the average value was taken as the reference value for that sample.

[0046] The spectral data of acetate fiber samples were preprocessed using a method that minimizes sample moisture content, resulting in preprocessed spectral data. This preprocessed spectral data, along with reference values, was used to train and validate the calibration model established using a multivariate calibration algorithm. The overall performance of the calibration model in this embodiment is shown in Table 2. Table 2 Performance of Acetate Fiber Sample Component Content Value Detection

[0047] As can be seen from the above, when detecting tobacco samples and acetate fiber samples, the correlation coefficient R is high, the root mean square error of calibration SEC and the root mean square error of cross-validation calibration Rmsecv are small, and there is a very strong linear correlation between the model prediction value and the reference value. Therefore, the analyzer in this embodiment has high accuracy, high reliability and good repeatability.

[0048] The other structures in this embodiment are the same as in Embodiment 1, and will not be described again here.

[0049] Example 3 like Figure 4 As shown, this embodiment of the invention provides a non-contact online near-infrared spectroscopy analysis method, based on the analyzer of Embodiment 1 or Embodiment 2, comprising: S100: Only the main light source 1 is turned on. The light emitted by the main light source 1 passes through the optical path module to form an emission cone-shaped optical path that illuminates the sample. The sampling end of the optical fiber 6 receives the light signal generated by the sample under the illumination of the light source module, which carries its composition information, and forms a receiving cone-shaped optical path. The receiving cone-shaped optical paths of multiple optical fibers 6 form a three-dimensional cross sampling area in the vertical direction of the sample. The emission cone-shaped optical path and the receiving cone-shaped optical path intersect in the vertical direction of the sample, so that the light signal generated after the light emitted by the light source module interacts with the sample is captured by the optical fiber 6 and transmitted to the spectrometer 7, which generates basic light intensity data. S200: Only turn on the selected auxiliary light source 2 to illuminate the sample and obtain the corresponding supplementary light intensity data; S300, placing the calibration plate 5 in the emission cone light path, shielding the sample, only turning on the main light source 1, the spectrometer 7 receives the light signal reflected by the calibration plate 5, and generates corresponding first calibration light intensity data; turning off the main light source 1, only turning on the auxiliary light source 2 used in step S200 to irradiate the calibration plate 5, and obtaining corresponding second calibration light intensity data; S400, only turning on the wavelength calibration light source 3, the spectrometer 7 receives the light signal reflected by the calibration plate 5, and generates corresponding third calibration light intensity data; S500, the data processing and analysis module pre-processes the basic light intensity data, the supplementary light intensity data, the first calibration light intensity data, the second calibration light intensity data and the third calibration light intensity data generated by the spectrometer 7 to obtain pre-processed sample spectrum data, and then calculates the pre-processed sample spectrum data based on a preset algorithm and outputs corresponding component content value.

[0050] In some embodiments, the pre-processing of step S500 includes background calibration, wavelength calibration and spectrum combination, The background calibration includes: Based on the first calibration light intensity data, the background calibration is performed on the basic light intensity data to obtain background-calibrated basic spectrum data; based on the second calibration light intensity data, the background calibration is performed on the supplementary light intensity data to obtain background-calibrated supplementary spectrum data; The wavelength calibration includes: Based on the third calibration light intensity data, third calibration spectrum data is generated, the third calibration spectrum data is compared with a preset mapping relationship to determine the current wavelength calibration deviation; based on the wavelength calibration deviation, the preset mapping relationship is updated to obtain updated wavelength calibration parameters; the background-calibrated basic spectrum data is wavelength-corrected by using the updated wavelength calibration parameters to output wavelength-calibrated basic spectrum data; the background-calibrated supplementary spectrum data is wavelength-corrected by using the updated wavelength calibration parameters to output wavelength-calibrated supplementary spectrum data; The spectrum combination includes: Based on the wavelength-calibrated basic spectrum data and the wavelength-calibrated supplementary spectrum data, the sample spectrum data is generated.

[0051] The embodiment mainly measures the moisture of the sample. The auxiliary light source 2 used in step S100 is an auxiliary light source 2 for improving the signal intensity at the characteristic absorption peak of moisture, specifically, the signal intensity near the characteristic absorption peak 1450 nm. The preprocessing of the embodiment also includes further processing of the sample spectral data obtained by spectral combination, including processing the sample spectral data according to the water content of the sample. According to the water content of the sample after wavelength calibration of the supplementary spectral data, if the water content of the sample is greater than the threshold value, the water content of the sample is high, and if the water content of the sample is lower than the threshold value, the water content is low.

[0052] The step of further processing the sample spectral data obtained by spectral combination includes: S510, selecting a preprocessing mode according to the water content of the sample. If the water content of the sample is greater than the threshold value, the water content of the sample is high, and if the water content of the sample is lower than the threshold value, the water content is low. If the water content of the sample is high, step S520 is performed, and if the water content of the sample is low, step S530 is performed. S520, if the water content of the sample is high, steps S521-S525 are performed: S521, Savitzky-Golay smoothing filtering is performed on the spectral data generated by the spectrometer 7 to suppress high-frequency noise, to obtain smoothed spectral data; S522, asymmetric least squares (ALS) is used to correct the baseline of the smoothed spectral data to obtain baseline-corrected spectral data; S523, standard normal variate transformation (SNV) is performed on the baseline-corrected spectrum to simultaneously correct the scattering effect caused by the difference in the physical state of the sample and the amplitude fluctuation caused by moisture, to obtain transformed spectral data; S524, the transformed spectral data is divided into a low waveband and a high waveband, and a second-order Savitzky-Golay derivative processing is performed on the high waveband to enhance the component resolution capability, to obtain high waveband spectral data; Savitzky-Golay smoothing filtering is performed on the low waveband to obtain low waveband spectral data. In this embodiment, the division of the low waveband and the high waveband is performed according to the effective spectrum by wavelength median or a preset ratio; S525, splicing the high waveband spectral data and the low waveband spectral data to obtain spliced spectral data, and performing mean centering on the spliced spectral data to obtain preprocessed spectral data; S530, if the water content of the sample is low, steps S531-S535 are performed: S531, Savitzky-Golay smoothing filtering is performed on the spectral data generated by the spectrometer 7 to suppress high-frequency noise, to obtain smoothed spectral data; S532, performing baseline correction on the smoothed spectral data by using asymmetric least squares (ALS) to obtain baseline-corrected spectral data; S533, performing standard normal variate (SNV) transformation on the baseline-corrected spectral data to simultaneously correct scattering effects caused by differences in physical state of the sample and amplitude fluctuations caused by water to obtain transformed spectral data. S534, performing continuum removal (CR) on the transformed spectral data, wherein when performing envelope fitting, the wavelength range where the characteristic absorption peaks are located is avoided to obtain removed spectral data; wherein the characteristic absorption peaks are determined by: obtaining absorption peaks of representative components according to chemical prior knowledge, and the absorption peaks of these representative components are the characteristic absorption peaks, for example, for tobacco, the characteristic absorption peaks mainly come from the overtone and combination vibrations of O–H, N–H and C–H bonds in sugars, nicotine, proteins and cellulose, and are usually located near 1200 nm, 1450-1500 nm and 1720-1760 nm; for acetate fibers, the characteristic absorption peaks mainly come from the overtone and combination vibrations of acetyl and ester bonds, and are usually located near 1170 nm, 1420 nm and 1720 nm; S535, performing mean centering on the removed spectral data to obtain preprocessed spectral data.

[0053] In this embodiment, the preset algorithm includes a correction model, and the correction model is established as follows: a set of representative calibration set samples are prepared, and spectral data of the calibration set samples are collected by the analyzer of embodiment one or embodiment two; the concentration or property reference value of the calibration set samples is determined by using a standard method; the preprocessed sample spectral data is associated with the reference value, and a correction model between the spectral data and the reference value is established by using a modeling algorithm.

[0054] In some embodiments, the correction model includes a linear regression model and a nonlinear regression model, and in step 500, the preprocessed sample spectral data is calculated based on the preset algorithm and the corresponding component content value is output, including: inputting the preprocessed sample spectral data into the linear regression model to obtain a first component content value; inputting the preprocessed spectral data into the nonlinear regression model to obtain a second component content value; and weighting and fusing the first component content value and the second component content value to obtain a final component content value. In this embodiment, the linear regression model is a partial least squares (PLS) model, and the nonlinear regression model is a support vector machine regression (SVR) model.

[0055] Specifically, the spectral data of the calibration set samples after preprocessing are divided into different bands based on the bands corresponding to the components, forming multiple sub-training sets. Linear regression and nonlinear regression models are trained using these corresponding sub-training sets to obtain the trained linear and nonlinear regression models. In the weighted fusion, a validation set sample, independent of the training set and with known true values, is used to calculate the prediction accuracy index of each model in the model set, and a fixed fusion weight is assigned to each model based on its prediction accuracy index. Let the weight be... ,in, For the first The root mean square error (RMSE) of each model on the validation set is n, where n is the total number of models. The validation set consists of representative samples covering the concentration range of the tested component that were not used in any model training.

[0056] The working process of the present application is as follows: (1) only open the main light source 1, the light emitted by the main light source 1 is collimated by the off-axis parabolic reflector 801 to form a high-quality parallel light beam, and then is condensed by the plano-convex lens 802, and then is transmitted to the reflector 9, and then is reflected by the reflector 9, and then the reflected light beam is irradiated on the sample through the protection window piece 10, and at the same time, the plano-convex lens 802 can move linearly in the horizontal direction, the size of the light spot of the light emitting path is controlled, the size of the light spot irradiated on the sample is only slightly larger than the sample, the light intensity in the range of the sample irradiated by the light source module is close to the maximum, and an independent emission light cone is constructed; the light irradiated on the sample is collected by the optical fiber 6, and then is transmitted to the photosensitive element in the spectrometer 7 after being collected, and this light path is a receiving conical light path, and at the same time, the optical fiber 6 can move linearly up and down in the direction perpendicular to the sample, the size of the light spot of the receiving light path is controlled, the size of the light spot receiving the sample is only slightly smaller than the light spot of the light emitting path, and the light spot of the receiving light path and the light spot of the light emitting path can infinitely approach the sample range, and the two are converged in the space of the sample to form a three-dimensional intersection sampling area, which is the cooperative effect of the emission conical light path and the receiving conical light path, thereby constructing a double-cone cooperative light path device. Optionally, the range of sample distribution, the irradiation area formed by the light source module, and the receiving area formed by all the optical fibers 6 infinitely approach each other, wherein the range of sample distribution accounts for less than 90-95% of the irradiation area formed by the light source module, and the receiving area formed by all the optical fibers 6 accounts for 90%-98% of the irradiation area formed by the light source module. The light response signal generated by the main light source 1 and the auxiliary light source 2 irradiating the sample is transmitted to the spectrometer 7 by the optical fiber 6 to generate basic light intensity data. (2) Only open the selected auxiliary light source 2 to irradiate the sample, and obtain the corresponding supplementary light intensity data. (3) Place the calibration plate 5 in the emission conical light path to shield the sample, only open the main light source 1, the spectrometer 7 receives the light signal reflected by the calibration plate 5, and generates corresponding first calibration light intensity data; close the main light source 1, only open the selected auxiliary light source 2 to irradiate the calibration plate 5, and obtain corresponding second calibration light intensity data; (4) only open the wavelength calibration light source 3, the spectrometer 7 receives the light signal reflected by the calibration plate 5, and generates corresponding third calibration light intensity data; (5) the data processing and analysis module pre-processes the basic light intensity data, the supplementary light intensity data, the first calibration light intensity data, the second calibration light intensity data and the third calibration light intensity data generated by the spectrometer 7, obtains the pre-processed sample spectrum data, and calculates and outputs the corresponding component content value based on the preset algorithm.

[0057] In summary, this invention provides a non-contact online near-infrared spectrometer, whose light source module uses a main light source 1 and several auxiliary light sources 2 with characteristic absorption peaks. It can realize enhanced analysis based on the direct response of characteristic wavelengths, overcoming the inherent limitations of absorption peak overlap and baseline drift in traditional diffuse reflectance spectra. This significantly improves the prediction accuracy, robustness, and ability to distinguish similar materials of the calibration model, thereby optimizing the measurement effect. The receiving module of this invention employs multiple optical fibers 6. The sampling ends of these fibers 6 are uniformly distributed circumferentially, and their heights vary perpendicular to the sample. The detection ends of the fibers 6 are uniformly arranged along the length of the slit in the spectrometer 7. Within a certain axial distance variation range, the sampling ends of the fibers 6 at different heights receive diffuse reflection light from different ranges, increasing the depth of field of the received light. This allows the instrument to better adapt to samples at different distances. Furthermore, this structure essentially constructs an "optical funnel" in space, enabling the collection of scattered light from the sample from multiple angles over a wide area, significantly improving light collection efficiency and maximizing the utilization efficiency of the light source energy. It also efficiently captures diffuse reflection / scattered light signals returned from the sample, achieving physical "adaptive" tolerance without the need for complex active feedback mechanisms. Moreover, the circumferential height variation of the fibers 6 ensures that they primarily receive signal light from the sample detection area, while naturally shielding stray environmental light from other angles, creating a spatial filtering effect. This effectively isolates and reduces interference from stray environmental light, forming a stray light suppression mechanism and effectively improving the signal-to-noise ratio. This invention also preprocesses the spectral data based on water content, which better preserves the characteristics of the spectral data and thus improves the reliability of the final component content values. Furthermore, this invention employs a hybrid approach of linear and nonlinear methods, resulting in higher prediction accuracy.

[0058] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A non-contact online near-infrared spectroscopy analyzer, characterized in that, include: The light source module includes a main light source (1), several auxiliary light sources (2), a wavelength calibration light source (3), and a light source switching mirror (4); the main light source (1) is used to provide near-infrared light to irradiate the sample; the auxiliary light sources (2) are used to emit light in a specific wavelength range to the sample to enhance the signal intensity at the characteristic absorption peaks of the components in the sample; the wavelength calibration light sources (3) are used to emit reference light with known characteristic wavelengths, and the reference light is used for wavelength calibration; the light source switching mirror (4) is used to guide the auxiliary light sources (2) and / or the wavelength calibration light sources (3) to the optical path module; An optical path module is used to guide the light emitted by the main light source (1) and / or the auxiliary light source (2) and / or the wavelength calibration light source (3) onto the sample, and / or to shape the light emitted by the main light source (1) and / or the auxiliary light source (2) and / or the wavelength calibration light source (3). The calibration plate (5) is located between the optical path module and the sample and is used for background calibration and wavelength calibration. The receiving module includes multiple optical fibers (6), each optical fiber (6) having a sampling end and a detection end. The sampling end is used to collect optical signals, and the detection end is coupled to a spectrometer (7) to transmit the optical signals to the spectrometer (7). The sampling ends of the multiple optical fibers (6) are evenly distributed circumferentially, and the sampling end of each optical fiber (6) has a different height position relative to the sampling ends of other optical fibers (6) in the direction perpendicular to the sample. The detection ends of the multiple optical fibers (6) are evenly arranged along the slit length direction of the spectrometer (7). Spectrometer (7), the spectrometer (7) is used to receive the optical signal transmitted by the optical fiber (6) and generate corresponding spectral data; A data processing and analysis module is used to process and analyze the spectral data.

2. The non-contact online near-infrared spectrometer according to claim 1, characterized in that, The optical path module includes: Shaping unit (8) is used to collimate and / or converge the light emitted by the light source module; A reflector (9) is located at the geometric center surrounded by the sampling ends of the plurality of optical fibers (6), and the reflector (9) is used to guide the light emitted by the light source module onto the sample.

3. The non-contact online near-infrared spectrometer according to claim 2, characterized in that, The shaping unit (8) includes an off-axis parabolic mirror (801), a plano-convex lens (802), and an extinction mirror tube (803). The off-axis parabolic mirror (801) and the plano-convex lens (802) are installed inside the extinction mirror tube (803). The light emitted by the light source module is sequentially irradiated onto the sample by the off-axis parabolic mirror (801), the plano-convex lens (802), and the mirror (9).

4. The non-contact online near-infrared spectrometer according to claim 1, characterized in that, It also includes a protective window (10), which is disposed between the optical path module and the sample. The protective window (10) is used to isolate the internal environment of the detection analyzer from the external environment. The light emitted by the light source module is guided by the optical path module and transmitted through the protective window (10) to irradiate the sample. The protective window (10) is tilted to reduce the specular reflection light of the light source module.

5. The non-contact online near-infrared spectrometer according to claim 1, characterized in that, The light source switching mirror (4) is placed in the optical path of the main light source (1) or removed from the optical path of the main light source (1) by rotation.

6. The non-contact online near-infrared spectrometer according to claim 1, characterized in that, One of the auxiliary light sources (2) is used to enhance the signal intensity at the moisture characteristic absorption peak.

7. A non-contact online near-infrared spectroscopy analysis method, based on the analyzer described in any one of claims 1-6, characterized in that, include: S100, only the main light source (1) is turned on. The light emitted by the main light source (1) passes through the optical path module to form an emission cone optical path that irradiates the sample. The sampling end of the optical fiber (6) receives the light signal generated by the sample under the illumination of the light source module, which carries its composition information, and forms a receiving cone optical path. The receiving cone optical paths of multiple optical fibers (6) form a three-dimensional cross sampling area in the vertical direction of the sample. The emission cone optical path and the receiving cone optical path intersect in the vertical direction of the sample, so that the light signal generated after the light emitted by the light source module interacts with the sample is captured by the optical fiber (6) and transmitted to the spectrometer (7). The spectrometer (7) generates basic light intensity data. S200, turn on only the selected auxiliary light source (2) to irradiate the sample and obtain the corresponding supplementary light intensity data; S300: Place the calibration plate (5) in the emission cone light path to block the sample, turn on only the main light source (1), and the spectrometer (7) receives the light signal reflected by the calibration plate (5) and generates the corresponding first calibration light intensity data; turn on only the auxiliary light source (2) used in step S200 to illuminate the calibration plate (5) and obtain the corresponding second calibration light intensity data. S400, only turn on the wavelength calibration light source (3), the spectrometer (7) receives the light signal reflected by the calibration plate (5) and generates the corresponding third calibration light intensity data; S500, the data processing and analysis module preprocesses the basic light intensity data, the supplementary light intensity data, the first calibration light intensity data, the second calibration light intensity data and the third calibration light intensity data generated by the spectrometer (7) to obtain the preprocessed sample spectral data, and then calculates the preprocessed sample spectral data based on the preset algorithm and outputs the corresponding component content value.

8. The non-contact online near-infrared spectroscopy analysis method according to claim 7, characterized in that, The preprocessing in step S500 includes background calibration, wavelength calibration, and spectral combination. The background calibration includes: Based on the first calibration light intensity data, background calibration is performed on the basic light intensity data to obtain the background-calibrated basic spectral data; based on the second calibration light intensity data, background calibration is performed on the supplementary light intensity data to obtain the background-calibrated supplementary spectral data. The wavelength calibration includes: A third calibration spectral data is generated based on the third calibration light intensity data. The third calibration spectral data is compared with a preset mapping relationship to determine the current wavelength calibration deviation. The preset mapping relationship is updated based on the wavelength calibration deviation to obtain updated wavelength calibration parameters. The updated wavelength calibration parameters are used to perform wavelength correction on the background-calibrated basic spectral data to output wavelength-calibrated basic spectral data. The updated wavelength calibration parameters are used to perform wavelength correction on the background-calibrated supplementary spectral data to output wavelength-calibrated supplementary spectral data. The spectral combination includes: The sample spectral data is generated based on the wavelength-calibrated basic spectral data and the wavelength-calibrated supplementary spectral data.

9. The non-contact online near-infrared spectroscopy analysis method according to claim 7, characterized in that, The preset algorithm includes a calibration model, which is established as follows: a set of representative calibration set samples are prepared, and their spectral data are collected by the analyzer described in any one of claims 1-6; the concentration or property reference value of the calibration set samples is determined by a standard method; the preprocessed sample spectral data is correlated with the reference value, and the calibration model between the spectral data and the reference value is established using a modeling algorithm.

10. The non-contact online near-infrared spectroscopy analysis method according to claim 9, characterized in that, The correction model includes a linear regression model and a nonlinear regression model. In step 500, the step of calculating and outputting the corresponding component content value based on the preprocessed sample spectral data according to a preset algorithm includes: inputting the preprocessed sample spectral data into the linear regression model to obtain a first component content value; inputting the preprocessed spectral data into the nonlinear regression model to obtain a second component content value; and weighting and fusing the first component content value and the second component content value to obtain the final component content value.

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