A hyperspectral backscattering function and scattering coefficient measuring device

Abstract

The application discloses a hyperspectral backscattering function and scattering coefficient measuring device, and belongs to the technical field of backscattering function measuring devices. The device comprises a light source. The light emitted by the light source is divided into two beams of collimated light through a one-to-two optical fiber jumper wire. One beam of collimated light is introduced into a reference light flux detector through a first optical fiber. The other beam of collimated light enters a first optical window through a second optical fiber and irradiates a scattering body in a sample cell. The scattered light generated after scattering by the scattering body is introduced through a second optical window and transmitted to a scattering flux detector through a third optical fiber. The scattering flux detector is used for receiving the scattered light from the scattering body and performing spectral spectroscopy and array detection on the scattered light. The reference light flux detector is used for receiving the light flux from the light source introduced through the first optical fiber and performing spectral spectroscopy and array detection on the light flux. The application solves the problem that the existing water backscattering function and scattering coefficient measuring device can only detect the backscattering coefficient of water at several wavelengths.

Description

Technical Field

[0001] This invention relates to volume scattering function measurement technology, specifically to a hyperspectral backscattering function and scattering coefficient measurement device. Background Technology

[0002] Volume Scattering Function (VSF, β(θ,λ)) measurement research can generally be divided into forward small-angle scattering measurement techniques, backscattering function measurement techniques within the 90°–180° range using single or multiple angles, and wide-angle (or multi-angle) volume scattering function measurement techniques for measuring scattered light signals from multiple angles within the 0°–180° range. Backscattering occurs when the angle between the scattered light and the incident light is greater than 90°. It is a function of the scattering angle and wavelength, and is an important fundamental optical parameter in water color remote sensing. Its magnitude depends only on the concentration of each component in the water body, making it one of the important intrinsic optical quantities. The backscattering coefficient of water bodies... Backscattering data plays a crucial role in oceanographic applications of optical remote sensing. Water backscattering information is determined by particle density, particle size, and refractive index; the particle size distribution and composition can be derived from the particle backscattering coefficient. Furthermore, it is closely related to the remote sensing reflectance of the water body. By establishing a model of their relationship, water composition can be directly inverted from remote sensing reflectance, laying the foundation for remote sensing inversion of water color component concentrations. Therefore, the backscattering properties of water bodies are of significant importance and value for ocean optical research, remote sensing research of water color components, and marine biogeochemical research.

[0003] Multispectral and hyperspectral volume scattering characteristics are key parameters for water color remote sensing and the optimization and improvement of light radiative transfer models. They can provide rich characteristic wavelength scattering information for ecosystem modeling and the identification of red tides and their dominant algae. Due to limitations in technology and device development, existing instruments for measuring the backscattering coefficient of water bodies can only detect the backscattering coefficient of water bodies at a few wavelengths. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hyperspectral backscattering function and scattering coefficient measuring device to solve the problem that existing water backscattering coefficient measuring instruments can only detect the backscattering coefficient of water at a few wavelengths.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A hyperspectral backscattering function and scattering coefficient measuring device includes a light source, a scattering flux detector, a reference light flux detector, and a sample cell;

[0007] The light emitted by the light source is split into two interconnected collimated beams via a 1-to-2 fiber optic jumper. One collimated beam is guided to the reference optical flux detector via the first fiber, while the other collimated beam enters the first optical window via the second fiber and illuminates the scatterer in the sample cell. The scattered light generated by the scatterer is guided through the second optical window and transmitted to the scattering flux detector via the third fiber.

[0008] The scattering flux detector is used to receive scattered light from the scatterer and perform spectral dispersion and array detection on it to obtain hyperspectral scattering flux in different bands;

[0009] The reference optical flux detector is used to receive the optical flux from the light source introduced by the first optical fiber and to perform spectral dispersion and array detection on it to obtain hyperspectral flux in different bands.

[0010] The sample cell is either a semi-open, light-shielding sample cell or a closed sample cell, and has the functions of light protection and liquid flow.

[0011] Furthermore, both the first and second light windows are quartz glass windows.

[0012] Furthermore, it also includes a sealed chamber, in which the light source, the scattering flux detector, and the reference optical flux detector are fixedly installed; the first optical window and the second optical window are watertightly installed in one end face of the sealed chamber.

[0013] Furthermore, the light source is a fiber-coupled output collimated halogen lamp, an LED lamp, or an LD lamp.

[0014] Furthermore, a watertight power supply and communication plug, a temperature and depth probe, and a non-contact power supply control switch are installed in the other end face of the sealed chamber.

[0015] Furthermore, both the scattering flux detector and the reference light flux detector are fiber-coupled collimated input fiber spectrometers. The grating inside the fiber spectrometer performs spectral dispersion, and the array detector inside it performs array detection.

[0016] Furthermore, the sample cell is a semi-open light-shielding sample cell or a closed sample cell, which has the functions of light protection and liquid flow.

[0017] Furthermore, backscattering measurements are based on the mathematical definition of the volume scattering function:

[0018]

[0019] In the formula, θ is the scattering angle, λ is the wavelength, Ω is the solid angle, and V is the scattering angle. θ For scattering, Φ s (θ) represents the scattering flux, and E represents the incident radiation;

[0020] The scattered flux DN at different wavelengths was obtained based on the scattered flux detector. θ (λ) and the hyperspectral flux DN in different bands detected by the reference optical flux detector mREF (λ), through Mie scattering theory and standard particles, wavelength correction of the light source is introduced. The hyperspectral distribution of the backscattering function at a certain angle θ is obtained by calibration using formula (2):

[0021]

[0022] Furthermore, based on β(θ,λ) and the backscattering coefficient b b The linear correlation between (λ) and the hyperspectral distribution of the backscattering coefficient is obtained based on formula (3):

[0023] b b (λ)=γ λ β(θ,λ) (3)

[0024] In the formula, γ λ This is the linear correlation coefficient.

[0025] Compared with the prior art, the advantages of this invention are as follows:

[0026] The hyperspectral backscattering function and scattering coefficient measuring device of the present invention receives scattered light from a scattering body through a scattering flux detector and performs spectral dispersion and array detection on it, thereby obtaining hyperspectral scattering flux in different wavelength bands; it also receives light flux from a light source introduced by a first optical fiber through a reference light flux detector and performs spectral dispersion and array detection on it, thereby obtaining hyperspectral flux in different wavelength bands; by combining the hyperspectral scattering flux and hyperspectral flux in different wavelength bands, the backscattering function and backscattering coefficient of water bodies at different wavelengths can be obtained, solving the problem that existing instruments for measuring the backscattering function and scattering coefficient of water bodies can only detect the backscattering coefficient of water bodies at a few wavelengths. Attached Figure Description

[0027] Figure 1 A schematic diagram of the internal structure of the hyperspectral backscattering function and scattering coefficient measuring device provided in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram illustrating the measurement principle of hyperspectral backscattering function and absorption coefficient provided in an embodiment of the present invention.

[0029] Figure 3 This is a structural diagram of the hyperspectral backscattering function and scattering coefficient measuring device provided in an embodiment of the present invention;

[0030] In the figure: 1. Light source; 2. Scattering flux detector; 3. Reference optical flux detector; 4. Sample cell; 5. 1-to-2 fiber optic jumper; 6. First fiber; 7. Second fiber; 8. First optical window; 9. Second optical window; 10. Third fiber; 11. Sealed chamber; 111. Upper end face; 112. Lower end face. Detailed Implementation

[0031] Example:

[0032] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0033] See Figure 1-3 As shown, the hyperspectral backscattering function and scattering coefficient measurement device provided in this embodiment mainly includes a light source 1, a scattering flux detector 2 at an angle θ (θ≥90°) to the light source, a reference light flux detector 3, and a sample cell 4.

[0034] In one specific embodiment, the light emitted by the light source 1 is split into two interconnected collimated beams via a split-fiber jumper 5. One collimated beam is guided to a reference optical flux detector 3 via a first optical fiber 6, while the other collimated beam enters a first optical window 8 via a second optical fiber 7 and illuminates a scatterer in the sample cell 4. The scattered light generated by the scatterer is guided through a second optical window 9 and transmitted to a scattering flux detector 2 via a third optical fiber 10. The scattering flux detector 2 is used to receive the scattered light from the scatterer and perform spectral dispersion and array detection to obtain hyperspectral scattering flux in different wavelength bands. The reference optical flux detector is used to receive the light flux from the light source guided by the first optical fiber 6 and perform spectral dispersion and array detection to obtain hyperspectral flux in different wavelength bands. This allows for the determination of the backscattering function and backscattering coefficient of water at different wavelengths, solving the problem that existing instruments for measuring the backscattering function and scattering coefficient of water can only detect the backscattering coefficient of water at a few wavelengths.

[0035] Specifically, backscattering measurements are based on the mathematical definition of the volume scattering function:

[0036]

[0037] In the formula, θ is the scattering angle, λ is the wavelength, Ω is the solid angle, and V is the scattering angle. θ For scattering, Φ s (θ) represents the scattering flux, and E represents the incident radiation; in seawater, β(θ,λ) also varies with time, space, and wavelength λ.

[0038] The scattered flux DN at different wavelengths was obtained based on the scattered flux detector 2. θ (λ) and the hyperspectral flux DN detected by the reference optical flux detector 3 in different bands mREF(λ), through Mie scattering theory and standard particles, wavelength correction of the light source is introduced. The hyperspectral distribution of the backscattering function at a certain angle θ is obtained by calibration using formula (2):

[0039]

[0040] Based on β(θ,λ) and the backscattering coefficient b b The linear correlation between (λ) and the hyperspectral distribution of the backscattering coefficient is obtained based on formula (3).

[0041] b b (λ)=γ λ β(θ,λ)…(3)

[0042] In the formula, γ λ This is the linear correlation coefficient.

[0043] Thus, by using this device, it is possible to obtain the volume scattering function and backscattering coefficient of water at different wavelengths.

[0044] In one specific embodiment, the light source 1, the scattering flux detector 2, and the reference light flux detector 3 are fixedly installed in a cylindrical scattering light flux detection sealed chamber 11 to facilitate underwater detection. The cylindrical sealed chamber 11 has a sealed structure at both the upper and lower ends. The upper end 111 is watertightly fitted with a watertight power supply and communication plug, a temperature and depth probe, and a power control switch to ensure the device can operate normally and communicate with the outside world. The lower end 112 of the cylindrical sealed chamber 11 is watertightly fitted with a first optical window 8 and a second optical window 9. Both the first optical window 8 and the second optical window 9 are quartz glass windows, and the distance between the centers of the two windows is R, which is the backscattering optical path length. The light source 1 is a fiber-coupled output collimated light source, and the scattering flux detector 2 and the reference light flux detector 3 are both fiber-coupled collimated input hyperspectral fiber spectrometers. The grating inside the fiber spectrometer completes the spectral dispersion, and the array detector inside completes the array detection.

[0045] To avoid interference from background light on hyperspectral measurements, the sample cell 4 has light-shielding and liquid-passing functions. Preferably, the sample cell 4 can be a semi-open light-shielding sample cell or a closed sample cell. To achieve hyperspectral flux detection, preferably, the light source 1 is a composite light source such as a halogen lamp, LED, and LD.

[0046] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A device for measuring hyperspectral backscattering function and scattering coefficient, characterized in that, This includes a light source, a scattering flux detector, a reference light flux detector, and a sample cell; The light emitted by the light source is split into two collimated beams that are connected to each other via a 1-to-2 fiber optic jumper. One collimated beam is guided to the reference optical flux detector via the first fiber, and the other collimated beam enters the first optical window via the second fiber and illuminates the scatterer in the sample cell. The scattered light generated after being scattered by the scatterer is guided through the second optical window and transmitted to the scattering flux detector via the third fiber. The scattering flux detector is used to receive scattered light from the scatterer and perform spectral dispersion and array detection on it to obtain hyperspectral scattering flux in different bands; The reference optical flux detector is used to receive the optical flux from the light source introduced by the first optical fiber and to perform spectral dispersion and array detection on it to obtain hyperspectral flux in different bands. The sample cell is a semi-open light-shielding sample cell or a closed sample cell, which has the functions of light protection and liquid flow. It also includes a sealed chamber, in which the light source, the scattering flux detector, and the reference optical flux detector are fixedly installed; the first optical window and the second optical window are watertightly installed in one end face of the sealed chamber. Both the scattering flux detector and the reference light flux detector are fiber-coupled collimated input fiber spectrometers. The grating inside the fiber spectrometer completes the spectral dispersion, and the array detector inside it completes the array detection. Backscattering measurements are based on the mathematical definition of the volume scattering function: In the formula, θ is the scattering angle, λ is the wavelength, Ω is the solid angle, and V is the scattering angle. θ For scattering, Φ s (θ) represents the scattered flux, and E represents the incident radiation; Hyperspectral scattering flux DN in different bands was obtained based on the scattering flux detector. θ (λ) and the hyperspectral luminous flux DN detected by the reference luminous flux detector in different bands mREF (λ), through Mie scattering theory and standard particles, wavelength correction of the light source is introduced. The hyperspectral distribution of the backscattering function at a certain angle θ is obtained by calibration using formula (2): Based on β(θ,λ) and the backscattering coefficient b b The linear correlation between (λ) and the hyperspectral distribution of the backscattering coefficient is obtained based on formula (3): b b (λ)=γ λ β(θ,λ) (3) In the formula, γ λ This is the linear correlation coefficient.

2. The hyperspectral backscattering function and scattering coefficient measuring device as described in claim 1, characterized in that, Both the first optical window and the second optical window are quartz glass windows.

3. The hyperspectral backscattering function and scattering coefficient measuring device as described in claim 1, characterized in that, The light source is a fiber-coupled output collimated halogen lamp, LED lamp, or LD lamp.

4. The hyperspectral backscattering function and scattering coefficient measuring device as described in claim 1, characterized in that, A watertight power supply and communication plug, a temperature and depth probe, and a non-contact power supply control switch are installed in the other end face of the sealed chamber.

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