A reflectivity spectrum detection device

Abstract

A reflectivity spectrum detection device provided by an embodiment of the present invention relates to the field of spectrum detection technology. The reflected light reflected by the surface of the target object when the ambient light is irradiated is received through a polarization structure, and the mirror reflected light perpendicular to the polarization direction in the reflected light is eliminated to obtain the reflected light parallel to the polarization direction; the spectrum sensor receives the reflected light parallel to the polarization direction, and identifies the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction; the upper spectrometer collects diffuse scattered light at multiple angles, and identifies the spectral intensity of multiple preset bands in the diffuse scattered light at multiple angles; the processor calculates the composition information of the target object according to the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction and the spectral intensity of multiple preset bands in the diffuse scattered light at multiple angles. Through the reflectivity spectrum detection device of the present application, the influence of the mirror reflected light can be avoided, thereby improving the accuracy of the measurement of the reflectivity spectrum.

Description

Technical Field

[0001] The invention relates to the technical field of spectrum detection, and in particular to a reflectivity spectrum detection device. Background Art

[0002] At present, hyperspectral technology plays an increasingly important role in the field of material analysis. By analyzing the hyperspectral reflectivity of materials, a variety of information such as the surface structure, composition, content and even temperature of the material can be obtained.

[0003] However, for water bodies with relatively smooth surfaces, the obtained reflectance spectrum often contains a large amount of specular reflection light of ambient light. These specular reflection lights do not contain any information related to the target objects, and will result in poor stability of the reflectivity obtained in real-time monitoring, making it difficult to conduct subsequent structure and component analysis. Summary of the invention

[0004] The purpose of the embodiment of the present invention is to provide a reflectivity spectrum detection device to improve the accuracy of the reflectivity spectrum measurement. The specific technical solution is as follows:

[0005] In a first aspect of an embodiment of the present application, a reflectivity spectrum detection device is first provided, comprising: a processor, a lens, a polarization structure, a spectrum sensor, a uniform light path, and an upper spectrometer;

[0006] The lens is arranged between the polarization structure and the spectrum sensor, the upper spectrometer is arranged at the rear end of the uniform light path, and the processor is connected to the spectrum sensor and the upper spectrometer respectively;

[0007] The polarization structure is used to receive the reflected light from the surface of the target object when the ambient light is irradiated, and eliminate the mirror reflected light perpendicular to the polarization direction in the reflected light to obtain the reflected light parallel to the polarization direction;

[0008] The lens is used to transmit the reflected light parallel to the polarization direction to the spectral sensor;

[0009] The spectral sensor is used to receive the reflected light parallel to the polarization direction and identify the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction;

[0010] The uniform light path is used to receive ambient light of multiple incident angles and diffuse the received ambient light to obtain diffuse scattered light at multiple angles;

[0011] The upper spectrometer is used to collect the multi-angle diffuse scattered light and identify the spectral intensity of multiple preset bands in the multi-angle diffuse scattered light;

[0012] The processor is used to calculate the composition information of the target object according to the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction and the spectral intensity of multiple preset bands in the multi-angle diffuse scattered light.

[0013] Optionally, the processor is specifically used to calculate the ratio of the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction to a reference spectrum to obtain the reflectivity of the target object, wherein the reference spectrum is positively correlated with the spectral intensity of multiple preset bands in the multi-angle diffusely scattered light; and calculate the composition information of the target object based on the reflectivity of the target object.

[0014] Optionally, the processor is also used to send sampling instructions to the spectral sensor and the upper spectrometer so that the spectral sensor and the upper spectrometer collect spectral intensity according to the sampling instructions; receive and store the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction and the spectral intensity of multiple preset bands in the multi-angle diffusely scattered light.

[0015] Optionally, the device further comprises a reflector;

[0016] The reflector is used to receive the reflected light from the surface of the target object irradiated by the ambient light, and reflect the reflected light from the surface of the target object irradiated by the ambient light to the polarization structure.

[0017] Optionally, the device further comprises a first conducting optical fiber;

[0018] The first transmission optical fiber is used to receive the reflected light parallel to the polarization direction, and transmit the reflected light parallel to the polarization direction to the spectrum sensor.

[0019] Optionally, the light uniforming optical path is a second transmission optical fiber;

[0020] The second transmission optical fiber is used to receive the multi-angle diffuse scattered light generated by the uniform light path, and transmit the multi-angle diffuse scattered light to the upper spectrometer.

[0021] Optionally, the spectral sensor is an imaging spectrometer;

[0022] The imaging spectrometer is used to identify the spectral intensity of a plurality of preset wavebands corresponding to the preset detection area in the reflected light parallel to the polarization direction.

[0023] Optionally, the composition information of the target object includes content information of a plurality of preset components;

[0024] The processor is further configured to generate a composition report of the target object according to the content information of the plurality of preset components and a preset template.

[0025] Optionally, the composition information of the target object includes content information of target pollutants;

[0026] The processor is also used to determine that the target object has been contaminated when the content of the target pollutant is greater than a preset threshold, and to generate and send pollution warning information.

[0027] A second aspect of the embodiments of the present application provides a mobile detection device, including a movable platform and any of the reflectance spectrum detection devices described above.

[0028] Beneficial effects of the embodiments of the present invention:

[0029] A reflectivity spectrum detection device provided by an embodiment of the present invention includes: a processor, a lens, a polarization structure, a spectrum sensor, a uniform light path, and an upper spectrometer; the lens is arranged between the polarization structure and the spectrum sensor, the upper spectrometer is arranged at the rear end of the uniform light path, and the processor is connected to the spectrum sensor and the upper spectrometer respectively; the polarization structure is used to receive reflected light reflected from the surface of a target object by ambient light, and eliminate the mirror reflected light perpendicular to the polarization direction in the reflected light to obtain reflected light parallel to the polarization direction; the lens is used to transmit the reflected light parallel to the polarization direction to the spectrum sensor; The spectral sensor is used to receive the reflected light parallel to the polarization direction and identify the spectral intensities of multiple preset bands in the reflected light parallel to the polarization direction; the uniform light path is used to receive ambient light at multiple incident angles and diffuse the received ambient light to obtain multi-angle diffusely scattered light; the upper spectrometer is used to collect the multi-angle diffusely scattered light and identify the spectral intensities of multiple preset bands in the multi-angle diffusely scattered light; the processor is used to calculate the composition information of the target object based on the spectral intensities of multiple preset bands in the reflected light parallel to the polarization direction and the spectral intensities of multiple preset bands in the multi-angle diffusely scattered light. Through the reflectivity spectrum detection device of the present application, not only can the reflected light parallel to the polarization direction be received by the spectrum sensor, and the spectral intensities of multiple preset bands in the reflected light parallel to the polarization direction be identified, the multi-angle diffuse scattered light can be collected by the upper spectrometer, and the spectral intensities of multiple preset bands in the multi-angle diffuse scattered light can be identified, but also the reflected light reflected by the ambient light irradiated on the surface of the target object can be received through the polarization structure, and the mirror reflected light perpendicular to the polarization direction in the reflected light can be eliminated. Therefore, when the processor calculates the composition information of the target object according to the spectral intensities of multiple preset bands in the reflected light parallel to the polarization direction and the spectral intensities of multiple preset bands in the multi-angle diffuse scattered light, the influence of the mirror reflected light can be avoided, thereby improving the accuracy of the reflectivity spectrum measurement.

[0030] Of course, it is not necessary to achieve all of the advantages described above at the same time to implement any product or method of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0032] Figure 1 A schematic diagram of the first structure of a reflectance spectrum detection device provided in an embodiment of the present application;

[0033] Figure 2 A second structural schematic diagram of a reflectivity spectrum detection device provided in an embodiment of the present application;

[0034] Figure 3 A third structural schematic diagram of the reflectivity spectrum detection device provided in an embodiment of the present application;

[0035] Figure 4 A fourth structural schematic diagram of a reflectance spectrum detection device provided in an embodiment of the present application;

[0036] Figure 5 A schematic diagram of a process for obtaining an ambient light mapping relationship model provided in an embodiment of the present application;

[0037] Figure 6 A schematic diagram of a process flow for material parameter inversion provided in an embodiment of the present application;

[0038] Figure 7 A fifth structural schematic diagram of the reflectivity spectrum detection device provided in an embodiment of the present application;

[0039] Figure 8 A sixth structural schematic diagram of a reflectance spectrum detection device provided in an embodiment of the present application;

[0040] Fig. 9 A seventh structural schematic diagram of a reflectivity spectrum detection device provided in an embodiment of the present application;

[0041] Fig.10 A schematic diagram of the installation environment of the mobile detection device provided in the embodiment of the present application;

[0042] Fig.11 A schematic diagram of the structure of a mobile detection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field based on this application belong to the scope of protection of the present invention.

[0044] First, the professional terms that may be used in the embodiments of the present application are explained:

[0045] Hyperspectral: refers to high spectral resolution. Hyperspectral technology is a technology that uses very narrow and continuous spectral channels to obtain light intensity information of the target. It has the characteristics of multiple bands. The number of spectral channels can reach more than hundreds, and the spectral channels are often continuous.

[0046] Reflectivity spectrum: The reflectivity spectrum is the selective reflection of electromagnetic waves of different wavelengths produced by the ground object. It has the characteristics of the ground object and is calculated by dividing the target spectrum reflected by the ground object by the reference spectrum received by the ground object (the spectrum reflected by 100% of the standard white board).

[0047] Ambient light mapping relationship calibration: The mapping relationship between the acquired ambient light spectrum and the reflection spectrum obtained from the standard diffuse reflection whiteboard is calibrated. In subsequent tests, only the ambient light spectrum information corresponding to the target needs to be measured, and the corresponding reference spectrum can be obtained using the mapping relationship.

[0048] In situ: refers to the original, normal, natural position or location. This technology will not change the location of the detection target and will not damage the detection target.

[0049] Specular reflected light: A beam of parallel light remains parallel light after being reflected by the medium surface. The reflection at this time is called specular reflected light.

[0050] Brewster's angle: also known as the polarization angle, is the condition that natural light must meet for the reflected light to be linearly polarized light after being reflected from the dielectric interface. The mirror reflected light incident along the Brewster's angle must be linearly polarized light with the polarization direction parallel to the dielectric surface.

[0051] In a first aspect of the embodiments of the present application, a reflectivity spectrum detection device is provided. Figure 1 , including: a processor 101, a lens 102, a polarization structure 103, a spectrum sensor 104, a uniform light path 105, and an upper spectrometer 106;

[0052] The lens is arranged between the polarization structure and the spectrum sensor, the upper spectrometer is arranged at the rear end of the uniform light path, and the processor is connected to the spectrum sensor and the upper spectrometer respectively;

[0053] The polarization structure 103 is used to receive the reflected light from the surface of the target object irradiated by the ambient light, and eliminate the mirror reflected light perpendicular to the polarization direction in the reflected light to obtain the reflected light parallel to the polarization direction;

[0054] The lens 102 is used to transmit the reflected light parallel to the polarization direction to the spectral sensor;

[0055] The spectral sensor 104 is used to receive the reflected light parallel to the polarization direction and identify the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction;

[0056] The light homogenization optical path 105 is used to receive ambient light of multiple incident angles and diffuse the received ambient light to obtain diffuse scattered light at multiple angles;

[0057] The upper spectrometer 106 is used to collect diffuse scattered light at multiple angles and identify the spectral intensity of multiple preset bands in the diffuse scattered light at multiple angles;

[0058] The processor 101 is used to calculate the composition information of the target object according to the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction and the spectral intensity of multiple preset bands in the diffuse scattered light at multiple angles.

[0059] Specifically, the lens in the embodiment of the present application can collect or image the reflected light of the target area, and can be directly connected to the spectral sensor or connected through an optical fiber relay. In actual use, the lens can be an imaging lens or a collimating lens, etc. Among them, the polarization structure can selectively transmit the polarization direction of the light collected by the lens, and only allow the light component parallel to the polarization direction to pass through, while eliminating the light component perpendicular to the polarization direction. According to the Fresnel theorem, the mirror reflected light incident at the Brewster angle is linearly polarized light with a polarization direction parallel to the medium surface. Therefore, using a polarization structure perpendicular to this direction can completely eliminate the mirror reflected light on the surface of the object and obtain a pure reflection spectrum. In actual use, the polarization structure can be a polarizer, a polarization film or a prism structure, etc. The above-mentioned spectral sensor can obtain the spectral intensity of the reflected light of the target area imaged or collected by the lens in different bands, and can be a multi-channel sensor, a hyperspectral sensor, a single-point fiber optic spectrometer or an imaging spectrometer, etc. For example, see Figure 2The light collected by the uniform light path 201 is received by the upper spectrometer 202 to obtain the ambient light spectrum. The light signal reflected by the target object first passes through the polarization structure 205 installed in front of the lens 204 to eliminate the mirror reflection light on the surface. The remaining light signal is received by the lens 204 and then collected by the lower spectrometer 203 to obtain the target spectrum. The industrial control board 206 performs exposure control and data storage for the data collection of the upper spectrometer 202 and the lower spectrometer 203. After the data collection is completed, the data analysis device 207 first pre-processes the data. After the pre-processing is completed, the target reflectance spectrum is calculated using the ambient light mapping relationship obtained by pre-calibration, and finally the material parameters are inverted according to the input model and displayed in real time.

[0060] The polarization structure in the embodiment of the present application can eliminate the specular reflection light on the surface of the target object, thereby obtaining a pure reflectivity spectrum of the surface of the target object. The target object in the embodiment of the present application can refer to an object with a smooth surface, such as a smooth surface ore, water body, etc.

[0061] Specifically, the uniform light path can receive ambient light at multiple incident angles, and the ambient light can be sunlight, sky light, light and other radiation modes of light, as a reference spectrum in the reflectivity calculation. The uniform light path needs to obtain ambient light in real time at different times and in different environments, and then measure the spectral intensity of multiple preset bands in the multi-angle diffuse scattered light through the upper spectrometer. The above processor can store the spectral intensity of multiple preset bands measured by the upper spectrometer, and calculate the composition information of the target object according to the stored spectral intensity. Specifically, the uniform light path collects light at different incident angles and makes it diffusely scattered at multiple angles after transmission, and then is collected by the spectral sensor. The purpose is to enable the ambient light acquisition module to effectively collect ambient light spectra at larger azimuth angles and zenith angles. The upper spectrometer is used to collect the diffusely scattered light after homogenization and detect its spectral intensity in different bands. In actual use, the upper spectrometer can be a multi-channel photodiode, a spectral sensor, or a hyperspectral sensor or a single-point fiber optic spectrometer.

[0062] Optionally, the composition information of the target object includes content information of multiple preset components; the processor is further used to generate a target object composition report based on the content information of the multiple preset components and a preset template. For example, the preset template may include a specified plurality of components, and a target object composition report is generated based on the content information of the multiple preset components and a preset template. The content information of the multiple preset components may be filled into a specified position in the preset template to obtain a composition report. In actual use, the preset template in the embodiment of the present application may include the components that need to be included in the report to be generated, as well as the order of each component, etc.

[0063] Optionally, the target object in the embodiment of the present application may refer to a water body, and the composition information of the target object includes the content information of the target pollutant; the processor is also used to determine that the target object has been polluted when the content of the target pollutant is greater than a preset threshold, and to generate and send pollution warning information. The reflectance spectrum detection device in the embodiment of the present application can be applied to the detection of polluted water bodies. For example, the device of the embodiment of the present application is installed near the sewage outlet, sewage pool, etc. of the factory. The water quality of the sewage outlet, sewage pool, etc. can be monitored by the device of the embodiment of the present application. For another example, the reflectance spectrum detection device of the embodiment of the present application can be installed on the lakeside or riverside where water quality monitoring is required, such as near a drinking water source. When it is detected that the monitored water body has been polluted, a warning message is generated, which can facilitate timely processing.

[0064] It can be seen that through the reflectivity spectrum detection device of the present application, not only can the reflected light parallel to the polarization direction be received by the spectral sensor, and the spectral intensities of multiple preset bands in the reflected light parallel to the polarization direction be identified, and the diffuse scattered light at multiple angles can be collected by the upper spectrometer, and the spectral intensities of multiple preset bands in the diffuse scattered light at multiple angles can be identified, but also the reflected light reflected by the ambient light irradiated on the surface of the target object can be received through the polarization structure, and the mirror reflected light perpendicular to the polarization direction in the reflected light can be eliminated. Therefore, when the processor calculates the composition information of the target object according to the spectral intensities of multiple preset bands in the reflected light parallel to the polarization direction and the spectral intensities of multiple preset bands in the diffuse scattered light at multiple angles, the influence of the mirror reflected light can be avoided, thereby improving the accuracy of the reflectivity spectrum measurement.

[0065] Optionally, the processor 101 is specifically used to calculate the ratio of the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction to a reference spectrum to obtain the reflectivity of the target object, wherein the reference spectrum is positively correlated with the spectral intensity of multiple preset bands in the diffusely scattered light at multiple angles; and calculate the composition information of the target object based on the reflectivity of the target object.

[0066] Optionally, the processor 101 calculates the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction and the ratio of the reference spectrum to obtain the reflectivity of the target object, and can also perform preprocessing, ambient light mapping relationship calibration, reflectivity calculation, material parameter inversion analysis, and data display on the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction and the spectral intensity of multiple preset bands in the diffuse scattered light at multiple angles. Specifically, the input data can be processed by denoising, filtering, etc. through preprocessing; the ambient light mapping relationship calibration can calibrate the difference between the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction and the spectral intensity of multiple preset bands in the diffuse scattered light at multiple angles; the reflectivity calculation can use the pre-calibrated ambient light mapping relationship to calculate the reflectivity spectrum of the target object; the material parameter inversion can use the input material parameter inversion model to perform inversion calculation of some specific parameters according to the calculated reflectivity spectrum of the target object, thereby obtaining the structure, composition and other information of the target in real time. In actual use, the device of the embodiment of the present application may also include a display unit, through which the calculated reflectivity spectrum and the parameters obtained by inversion can be displayed in real time. For example, see Figure 3 In the hardware module part, the ambient light acquisition module is used to acquire the ambient light spectrum. The target spectrum acquisition module is used to acquire the reflection spectrum of the target object. Then, the data acquisition module is used to pre-process and cache the spectra acquired by the ambient light acquisition module and the target spectrum acquisition module. Finally, in the software module part, the data analysis module is used to calculate the reflectance of the target spectrum, so as to analyze the components according to the calculated reflectance.

[0067] Specifically, the processor calculates the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction, and the ratio of the spectral intensity to the reference spectrum to obtain the reflectivity of the target object, which can be obtained by the preset formula:

[0068]

[0069] Calculate the reflectivity of the target object, where I o is the spectral intensity of multiple preset bands in the light component parallel to the polarization direction, I r is the spectral intensity of multiple preset bands in the diffuse scattered light at multiple angles, r is the ambient light mapping coefficient, and the reference spectrum I Ref =r*I r .

[0070] In the actual calibration process, the above preset formula can also include the following forms:

[0071]

[0072] The spectral sensor and the upper spectrometer can be used to measure the reflection spectrum of the whiteboard at two mutually perpendicular polarization angles, with the polarization direction parallel to the medium surface as 0°, the polarization direction of the polarizer is set to 0°, and the spectral sensor and the upper spectrometer synchronously collect the original spectra, which are I and w0 with I r0 Then the polarization direction of the polarizer is set to 90°, and the spectral sensor and the upper spectrometer synchronously collect the original spectra, which are I w90 with I r90 In actual use, the ambient light mapping relationship can be calibrated to obtain the mapping relationship between the ambient light spectrum and the reflection spectrum obtained by the standard diffuse reflection whiteboard, and then the ambient light spectrum can be directly calculated through the mapping relationship, so as to calculate the reflectivity of the target object according to the ambient light spectrum.

[0073] Optionally, the processor 101 is also used to send sampling instructions to the spectral sensor and the upper spectrometer so that the spectral sensor and the upper spectrometer collect spectral intensity according to the sampling instructions; receive and store the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction and the spectral intensity of multiple preset bands in the diffusely scattered light at multiple angles.

[0074] Specifically, the processor 101 may include two parts: data acquisition and data storage. During data acquisition, the processor may send parameters such as acquisition frame rate, exposure time, acquisition time, and average number of acquired spectral data to the spectral sensor and the upper spectrometer through sampling instructions, so that the spectral sensor and the upper spectrometer acquire the spectral intensity according to the received parameters. During data storage, the processor may store the data collected by the spectral sensor and the upper spectrometer, which may be implemented in various ways such as a memory card or cloud storage.

[0075] For details, see Figure 4, 401 in the figure is a uniform light path, which is used to collect light with different incident angles and make it diffusely scattered at multiple angles after transmission, and can effectively obtain the ambient light spectrum at a larger azimuth angle and zenith angle, and then use a spectral sensor to collect it. In the figure, 402 is an upper spectrometer, which is used to collect the diffusely scattered ambient light after homogenization and detect its spectral intensity in different bands; 403 is a lower spectrometer, which can obtain the spectral intensity of the reflected light of the target area imaged or collected by the lens in different bands. In actual use, 402 and 403 can use multi-spectral or hyperspectral sensors, or single-point fiber optic spectrometers. In the figure, 404 is a lens, which can collect or image the reflected light of the target area and is directly connected to the lower spectrometer 403. In the figure, 405 is a polarization structure, which includes a linear polarizer and a rotating mount, which is used to change the polarization direction of the polarizer to achieve the purpose of completely eliminating the mirror reflection light on the surface of the object. In the figure, 406 is an industrial control board, which controls the data acquisition of the upper spectrometer 402 and the lower spectrometer 403 and stores the collected data. In the figure, 407 is a data analysis device, which is used for the calculation of target reflectivity, material parameter inversion analysis and data display. The uniform light path 401 is relatively fitted with the upper spectrometer 402 and installed vertically upward, facing the zenith direction. The lower spectrometer 403, the lens 404 and the polarization structure 405 are combined together, and are installed obliquely downward at an inclination angle near the Brewster angle of the target surface (generally, the deviation does not exceed 10°) to collect the spectrum of the target area below. During the detection process, the uniform light path and the target object will be irradiated by ambient light, and the irradiance of the two is basically the same. The light collected by the uniform light path is received by the upper spectrometer 402 to obtain the ambient light spectrum. The light signal reflected by the target object first passes through the polarization structure 405 installed in front of the lens 404 to eliminate the mirror reflection light on the surface. The remaining light signal is received by the lens 404 and then collected by the lower spectrometer 403 to obtain the target spectrum. The industrial control board 406 performs exposure control and data storage on the data collection of the upper spectrometer 402 and the lower spectrometer 403. After data collection is completed, the data analysis device 407 first pre-processes the data. After pre-processing is completed, the target reflectance spectrum is calculated using the ambient light mapping relationship obtained by pre-calibration, and finally the material parameters are inverted according to the input model and displayed in real time.

[0076] Specifically, in actual use, the process of calculating the reflectance spectrum of the target may include:

[0077] 1. Ambient light mapping relationship calibration process

[0078] In order to calculate the spectral reflectance of the target object, it is necessary not only to obtain the reflection spectrum of the target, but also to obtain the spectrum of the incident radiation flux as a reference spectrum. Although the ambient light acquisition module can directly obtain the ambient spectrum corresponding to the target, the ambient spectrum at this time does not take into account the difference between the ambient light acquisition module and the target spectrum acquisition module, so it cannot be directly used as a reference spectrum. A common method for obtaining a reference spectrum is to replace it with the intensity value of the reflection of a standard diffuse reflection whiteboard. This method first requires the ambient light mapping relationship between the ambient light spectrum obtained by the ambient light acquisition module and the reflection spectrum obtained by the standard diffuse reflection whiteboard to be calibrated. In subsequent tests, only the ambient light acquisition module needs to be used to measure the ambient light spectrum information corresponding to the target, and the ambient light mapping relationship can be used to obtain the corresponding reference spectrum. Ambient cursor timing, because the target spectrum acquisition module has a polarization structure, the directly measured whiteboard reflection spectrum will be affected by the polarization of the ambient light. Therefore, it is necessary to use the target spectrum acquisition module to measure the reflection spectrum of the whiteboard at two mutually perpendicular polarization angles. The sum of the two can reflect the true whiteboard reflection spectrum. The specific steps for calibrating the ambient light mapping relationship are as follows:

[0079] 1.1 Measurement environment setup. The measurement needs to be performed outdoors in an open environment to ensure that the ambient light illumination corresponding to the sensing area of ​​the target spectrum acquisition module and the ambient light acquisition module is consistent and not affected by shadows. When measuring, it is necessary to first calculate the Brewster angle θ of the target object, and then use the target spectrum acquisition module to collect the reflection spectrum at an inclination angle near θ. Place the whiteboard in the collection area of ​​the target spectrum acquisition module so that the whiteboard can completely cover the collection range of the target spectrum acquisition module. The measurement diagram of the whiteboard calibration is shown in the figure below. Figure 5 shown.

[0080] 1.2 Synchronously acquire the ambient light spectrum and the whiteboard spectrum at different polarization angles. When starting calibration, in order to eliminate the influence of ambient light polarization, it is necessary to use the target spectrum acquisition module to measure the reflectance spectrum of the whiteboard at two mutually perpendicular polarization angles. Taking the polarization direction parallel to the medium surface as 0°, first set the polarization direction of the polarizer to 0°, so that the target spectrum acquisition module and the ambient light acquisition module synchronously collect the original spectra, respectively. w0 with I r0 Then the polarization direction of the polarizer is set to 90°, and the target spectrum acquisition module and the ambient light acquisition module are synchronously collected to obtain the original spectrum. w90 with I r90 Since the ambient light intensity varies greatly at different times and in different weather conditions, it is impossible to use a uniform exposure time to acquire the original spectrum. During the acquisition process, the data acquisition module needs to be used to adjust the exposure time of the target spectrum acquisition module and the ambient light acquisition module.

[0081] 1.3 Spectral preprocessing, denoising, filtering and other processing processes are performed on the input data.

[0082] 1.4 Calculate the ambient light mapping relationship, see Figure 5 For the total reflection spectrum of the whiteboard, it is necessary to add the reflection spectra of the whiteboard measured at polarization angles of 0° and 90°, that is, I w0 +I w90 As for the ambient spectrum at this time, since the ambient spectrum measured twice by the ambient light acquisition module may be different, the two measured ambient spectra are averaged here to serve as the ambient spectrum corresponding to the whiteboard reflection spectrum, that is, (I r0 +I r90 ) / 2. Therefore, the ambient light mapping coefficient r can be expressed as the ratio of the whiteboard reflection spectrum to the corresponding ambient spectrum, that is, r = 2*(I w0 +I w90 ) / (I r0 +I r90 ), and then save this mapping relationship. In subsequent measurements, there is no need to use a whiteboard to obtain a reference spectrum. You only need to use the ambient light acquisition module to measure the ambient spectrum I r , the ambient light mapping coefficient can be used to calculate the reference spectrum I Ref =r*I r .

[0083] 2. Reflectivity calculation process

[0084] After the ambient light mapping relationship is calibrated, the system can be used directly to monitor the reflectivity of ground objects in real time. By synchronously collecting the ambient spectrum of the ambient light acquisition module and the target spectrum of the target spectrum acquisition module, the reflectivity spectrum of the target can be directly calculated. The specific steps for reflectivity calculation are as follows:

[0085] 2.1 Acquire the ambient light spectrum and the target object spectrum simultaneously. The measurement needs to be carried out in an open environment to ensure that the ambient light illumination corresponding to the sensing area of ​​the target spectrum acquisition module and the ambient light acquisition module is consistent and there is no shadow obstruction. When measuring, the target spectrum acquisition module needs to be tilted near the Brewster angle θ of the surface of the object to collect the reflection spectrum, such as Figure 4 The target spectrum acquisition module and the ambient light acquisition module start to collect the original spectrum synchronously, which are I o with I r During the acquisition process, the data acquisition module needs to be used to adjust the exposure time of the target spectrum acquisition module and the ambient light acquisition module.

[0086] 2.2 Spectral preprocessing, denoising, filtering and other processing processes are performed on the input data.

[0087] 2.3 Loading the ambient light mapping relationship model, loading the previously acquired ambient light mapping relationship model, and using the ambient light spectrum I measured by the ambient light acquisition module r , we can calculate the reference spectrum I Ref =r*I r .

[0088] 2.4 Calculation of ground reflectance spectrum, see Figure 6 Since the target spectrum acquisition module has a polarization structure, the measured diffuse reflection spectrum of the target object will also be attenuated by about 50%. Therefore, the spectrum I measured by the target spectrum acquisition module can generally be o The target reflection spectrum is taken as twice of the reference spectrum I Ref , the reflectance spectrum can be directly calculated using the following formula:

[0089]

[0090] Among them, I o is the spectral intensity of multiple preset bands in the light component parallel to the polarization direction, I r is the spectral intensity of multiple preset bands in the diffuse scattered light at multiple angles, r is the ambient light mapping coefficient, and the reference spectrum I Ref =r*I r , the polarization direction parallel to the medium surface is 0°, the polarization direction of the polarizer is set to 0°, and the spectral sensor and the upper spectrometer synchronously collect the original spectra respectively. w0 with I r0 Then the polarization direction of the polarizer is set to 90°, and the spectral sensor and the upper spectrometer synchronously collect the original spectra, which are I w90 with I r90 .

[0091] In most cases, the reflection spectrum of the target object has no or only a small polarization characteristic, so the above formula can be used directly to calculate the reflectance spectrum with high accuracy. However, for some objects with polarized reflection characteristics, since the polarization structure will affect the spectrum type or intensity of the target reflection spectrum, the error calculated directly using the above formula will be large. In this case, the spectral polarization characteristics of the target can be calibrated first to obtain the polarization mapping relationship model of the target spectrum, and then this model can be introduced during the reflectance spectrum calculation to greatly improve the measurement accuracy of these objects with polarized reflection characteristics.

[0092] After obtaining the reflectivity spectrum of the ground target, the data analysis module can perform inversion calculations on some specific parameters based on the input model, thereby obtaining real-time information on the structure, composition, and other aspects of the target. Since the mirror reflection light on the target surface is effectively eliminated, the measured reflectivity spectrum is more accurate, and the inversion parameters are more accurate.

[0093] Optional, see Figure 7 , the above-mentioned device also includes a reflector; used to receive the reflected light reflected by the ambient light irradiating the surface of the target object, and reflect the reflected light reflected by the ambient light irradiating the surface of the target object to the polarization structure. Optionally, 708 in the figure is a reflector, and the light collected by the uniform light path 701 is received by the upper spectrometer 702 to obtain the ambient light spectrum. The lower spectrometer 703 and the lens 704 are changed to vertically downward measurement, which is more conducive to the assembly of the two spectrometers. The polarization structure 705 is still measured at the Brewster angle θ, and is not directly connected to the lens 704. The reflector 708 is placed at an inclination angle of θ / 2, and is used to reflect the light information collected by the polarization structure 705 into the lens 704, and then collected by the lower spectrometer 703. The data analysis device 707 is connected to the industrial control board 706. The calibration and reflectivity calculation process of this embodiment remains unchanged.

[0094] Optional, see Figure 8 , the polarization structure is an optical fiber, and the above device also includes a first transmission optical fiber; the first transmission optical fiber is used to receive the reflected light parallel to the polarization direction, and transmit the reflected light parallel to the polarization direction to the spectrum sensor. Optionally, the uniform light path is a second transmission optical fiber; the second transmission optical fiber is used to receive the multi-angle diffuse scattered light generated by the uniform light path, and transmit the multi-angle diffuse scattered light to the upper spectrometer. Figure 8 809 and 810 are optical fibers, the uniform light path 801 is connected to the upper spectrometer 802 through the optical fiber 809, the lower spectrometer 803 is connected to the polarization structure 805 through the optical fiber 810, the data analysis device 807 is connected to the industrial control board 806, and there is no specific requirement for the installation angle of the upper spectrometer 802 and the lower spectrometer 803. It is only necessary to control the installation angle of the uniform light path 801 and the polarization structure 805 to remain unchanged, and the upper and lower spectrometers can collect the ambient light and target reflected light information through the optical fiber light guide. The upper and lower spectrometers can adopt the optical fiber spectrometer structure, and can also receive the signal introduced by the optical fiber through the optical fiber adapter. The calibration and reflectivity calculation process of this embodiment remains unchanged.

[0095] Optional, see Fig. 9, the spectral sensor is an imaging spectrometer; the imaging spectrometer is used to identify the spectral intensity of multiple preset bands corresponding to the preset detection area in the reflected light parallel to the polarization direction. In the figure, 911 is an imaging spectrometer. By replacing the single-point spectrometer with an imaging spectrometer, the imaging spectrometer 911 and the lens 904 are still combined together to detect along the Brewster angle, the uniform light path 901 is connected to the upper spectrometer 902, the imaging spectrometer 911 is connected to the polarization structure 905 through the lens 904, and the data analysis device 907 is connected to the industrial control board 906, so that the hyperspectral image of the entire detection area can be obtained, rather than the spectrum of a single point. Therefore, the whiteboard area can be accurately extracted during the calibration process to prevent the detection area from exceeding the whiteboard range. At the same time, the reflectivity of the target object obtained is no longer a spectral curve, but a whole hyperspectral reflectivity cube, so that the detection of the material structure is more reliable. And the calibration and reflectivity calculation process is basically unchanged from the above embodiment, only in the calibration of the ambient light mapping relationship, an additional step of the extraction process of the whiteboard area in the hyperspectral image is required.

[0096] In actual use, the target surface to be measured is not limited to the horizontal direction, but can be any angle. It is only necessary to change the measurement angle of the target spectrum acquisition module accordingly to be near the Brewster angle, and the calibration and reflectivity calculation processes remain unchanged.

[0097] See also Fig.10 In actual use, when using hyperspectral technology for water quality testing, the acquisition of water-leaving radiation is an extremely important part of determining its detection accuracy. The water reflected light directly obtained by the probe often contains a large amount of specular reflections on the water surface (mainly including sky reflected light and solar flares). These specular reflections do not carry any water information and must be eliminated in the preliminary processing work. This is a key step to improve the accuracy of water quality detection. Fig.10 For the application in the field of hyperspectral water quality monitoring. Under the irradiation of sky light, the radiation obtained by the uniform light material and the water area is basically the same. The ambient light acquisition module and the target spectrum acquisition module respectively collect the ambient spectrum and the water body reflection spectrum in real time. The mirror reflection light of the water surface is almost completely eliminated after passing through the polarization structure, so the target spectrum acquisition module can collect a relatively pure water-leaving radiation spectrum. According to the previously calibrated ambient light mapping relationship model, the reflectivity spectrum of the water-leaving radiation can be calculated. Then the reflectivity spectrum is input into the water body parameter inversion model to calculate the water quality parameter value of the current water quality. This solution can realize all-weather online water quality monitoring. Due to the elimination of water surface reflection light, the stability and accuracy of detection have been greatly improved compared with traditional methods.

[0098] In the second aspect of the embodiment of the present application, see Fig.11, a mobile detection device is also provided, including a movable platform and any of the above-mentioned reflectivity spectrum detection devices.

[0099] Specifically, this technical solution can be applied to other component and structure detection fields, such as water, soil or ore composition monitoring. Soil monitoring is mainly to obtain the current soil composition information to determine the impact on the growth of crops; while ore monitoring is mainly to obtain the type and location of ore in the mine for mining. The hyperspectral remote sensing technology of this embodiment can obtain the target's composition information in real time. And it solves the problem that the existence of mirror reflection light makes it difficult for traditional monitoring technology to obtain accurate target reflectance spectra. For example, in soil composition monitoring, when there is water accumulation or ice in the target area, the measurement accuracy will be significantly reduced; for example, in ore composition monitoring, many ores with smooth surfaces will have strong mirror reflection light, which will also greatly affect the detection results. Fig.11 The above-mentioned embodiment is applied to soil / ore composition monitoring, with UAV hyperspectral remote sensing as the platform. In an open outdoor environment, the radiation obtained by the uniform light material on the UAV and the target area is basically the same. The ambient light acquisition module and the target spectrum acquisition module respectively collect the ambient spectrum and the reflection spectrum of the target area in real time. The mirror reflection light on the target surface is almost completely eliminated after passing through the polarization structure, so a more accurate reflectance spectrum of the target area can be calculated. Due to the use of a planar array imaging spectrometer, the reflectance cube of the entire detection area can be obtained, rather than the spectrum of a single point. This makes it possible to accurately extract the whiteboard area during the calibration process, and the calibration process is more convenient and reliable. At the same time, the components and structural parameters at different positions in the target area can also be inverted, which is very important in the field of soil and ore composition monitoring.

[0100] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk Solid State Disk (SSD)), etc.

[0101] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0102] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A reflectivity spectrum detection device, characterized in that: include: Processor, lens, polarization structure, spectral sensor, uniform light path, upper spectrometer; The lens is arranged between the polarization structure and the spectrum sensor, the upper spectrometer is arranged at the rear end of the uniform light path, and the processor is connected to the spectrum sensor and the upper spectrometer respectively; The polarization structure is used to receive the reflected light from the surface of the target object when the ambient light is irradiated, and eliminate the mirror reflected light perpendicular to the polarization direction in the reflected light to obtain the reflected light parallel to the polarization direction; the polarization structure receives the reflected light from the surface of the target object when the ambient light is irradiated at a Brewster angle, and is not directly connected to the lens; The device further comprises a reflector for receiving the reflected light parallel to the polarization direction and reflecting the reflected light parallel to the polarization direction to the lens; the reflector is placed at an inclination angle of half the Brewster angle; The lens is used to transmit the reflected light parallel to the polarization direction to the spectral sensor; The spectral sensor is used to receive the reflected light parallel to the polarization direction and identify the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction; The uniform light path is used to receive ambient light of multiple incident angles and diffuse the received ambient light to obtain diffuse scattered light at multiple angles; The upper spectrometer is used to collect the multi-angle diffuse scattered light and identify the spectral intensity of multiple preset bands in the multi-angle diffuse scattered light; The processor is used to calculate the composition information of the target object based on the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction and the spectral intensity of multiple preset bands in the multi-angle diffusely scattered light; wherein the calculation process includes calculating the ratio of the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction to a reference spectrum to obtain the reflectivity of the target object, wherein the reference spectrum is positively correlated with the spectral intensity of multiple preset bands in the multi-angle diffusely scattered light; and calculating the composition information of the target object based on the reflectivity of the target object.

2. The device according to claim 1, characterized in that The processor is also used to send sampling instructions to the spectral sensor and the upper spectrometer so that the spectral sensor and the upper spectrometer collect spectral intensity according to the sampling instructions; receive and store the spectral intensity of multiple preset bands in the reflected light parallel to the polarization direction and the spectral intensity of multiple preset bands in the multi-angle diffusely scattered light.

3. The device according to claim 1, characterized in that The apparatus further comprises a first conducting optical fiber; The first transmission optical fiber is used to receive the reflected light parallel to the polarization direction, and transmit the reflected light parallel to the polarization direction to the spectrum sensor.

4. The device according to claim 1, characterized in that The uniform light path is a second transmission optical fiber; The second transmission optical fiber is used to receive the multi-angle diffuse scattered light generated by the uniform light path, and transmit the multi-angle diffuse scattered light to the upper spectrometer.

5. The device according to claim 1, characterized in that The spectral sensor is an imaging spectrometer; The imaging spectrometer is used to identify the spectral intensity of a plurality of preset wavebands corresponding to the preset detection area in the reflected light parallel to the polarization direction.

6. The device according to claim 1, characterized in that The component information of the target object includes content information of a plurality of preset components; The processor is further configured to generate a composition report of the target object according to the content information of the plurality of preset components and a preset template.

7. The device according to claim 1, characterized in that The composition information of the target object includes content information of the target pollutant; The processor is also used to determine that the target object has been contaminated when the content of the target pollutant is greater than a preset threshold, and to generate and send pollution warning information.

8. A mobile detection device, characterized in that: It comprises a movable platform and the reflectivity spectrum detection device described in any one of claims 1-7.

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