Citrus huanglongbing detection device and system based on conjugate optical multispectral acquisition

Abstract

The utility model discloses a Candidatus Liberobacter asiaticum detection device and system based on conjugate optical multispectral acquisition, the Candidatus Liberobacter asiaticum detection device comprises a conjugate optical lens composed of a lens cone and two biconvex lenses, the two biconvex lenses are arranged at two ends of the lens cone in parallel, a sample to be detected is located at a first conjugate point, and the two biconvex lenses are arranged in parallel. A target surface of the sensor chip is arranged at the second conjugate point; the sensor chip can collect spectral energy of at least four wave bands, the sensor chip is electrically connected with a micro-control unit, and the micro-control unit is electrically connected with a display unit. According to the utility model, a certain optical axis angle can be set according to actual conditions, and according to the diameter and curvature radius of the biconvex lens, light rays reflected beyond the optical axis angle cannot enter the optical lens, and light rays reflected within the optical axis angle range are refracted into parallel light through the first biconvex lens. And the light rays are converged at the second conjugate point through the second biconvex lens, so that the light rays with larger optical axis angles are filtered, and the utilization rate of energy is ensured.

Description

Technical Field

[0001] The utility model relates to the technical fields of conjugate optics and multispectral detection, and particularly relates to a citrus huanglongbing detection device and system for conjugate optical multispectral acquisition. Background Art

[0002] Huanglongbing is one of the most serious threats to the citrus planting industry. It is a devastating disease for citrus, which will ultimately lead to the death of the tree body. Oranges, tangerines, sweet oranges, lemons and grapefruits are all susceptible to the disease. The citrus planting areas in nearly 50 countries and regions in the world are all infected with this disease. The disease is mainly distributed in North and South America, Asia, Oceania, Africa and other places. If it is allowed to spread, it will cause a fatal blow to the citrus industry in China, resulting in dead trees and destroyed orchards. Unfortunately, a large number of experiments have proved that citrus huanglongbing cannot be cured completely. At present, the main measure for huanglongbing is prevention and control. Once a diseased plant is found, it must be removed root and all, and the surrounding soil must be thoroughly cleaned to control the source of transmission, so as to prevent other healthy plants from being infected. Therefore, how to effectively distinguish huanglongbing plants from other plants with similar symptoms and study and establish a rapid detection method and technology for huanglongbing has important economic value and social benefits.

[0003] The existing citrus huanglongbing detections mainly have the following methods:

[0004] The first method is the field artificial diagnosis method, that is, observing by eyes and judging according to experience. Although it is simple and easy to implement, it has the disadvantages of strong subjectivity and low discrimination accuracy.

[0005] The second method is the laboratory pathological analysis method. Polymerase chain reaction is performed on the leaves of the detected plants to judge whether they are infected with huanglongbing. This method is accurate, but the detection speed is slow, the cycle is long, the equipment is expensive, and it can only be detected in the laboratory, and it is difficult to meet the detection requirements of large outdoor orchards.

[0006] The above two detection methods have great limitations and are difficult to detect in a large range in the orchard. Therefore, the third method, spectral detection method, is commonly used in the current orchard detection, that is, using the hyperspectral images of healthy leaves and huanglongbing leaves or the spectral data differences in the near-infrared band to diagnose huanglongbing. However, on the one hand, due to the uneven surface of the leaves, the reflected light is irregular diffuse reflection. Therefore, the correlation between adjacent bands in these spectral information is high, and there is a lot of redundant information, which increases the processing complexity and processing time. On the other hand, hyperspectral cameras and near-infrared spectrometers are expensive, and when collecting spectral signals outdoors, they are greatly affected by the angle of the reflected light of the leaves, and the data fluctuates violently. Content of the Utility Model

[0007] Aiming at the deficiencies of the prior art, the utility model aims to provide a citrus huanglongbing detection device and system for conjugate optical multispectral acquisition, so as to solve the problems in the prior art that the spectral detection equipment for huanglongbing is easily interfered by stray light, resulting in severe data fluctuations affecting the detection results and high costs. The specific technical solutions are as follows:

[0008] A citrus huanglongbing detection device for conjugate optical multispectral acquisition, including a conjugate optical lens composed of a lens barrel and two double convex lenses. The two double convex lenses are arranged in parallel at both ends of the lens barrel. The two conjugate points of the conjugate optical lens are the first conjugate point and the second conjugate point respectively. The sample to be detected is located at the first conjugate point, and the target surface of the sensor chip is arranged at the second conjugate point;

[0009] The sensor chip can collect spectral energy in at least four bands. The sensor chip is electrically connected to a micro control unit, and the micro control unit is electrically connected to a display unit. The micro control unit converts the spectral energy signals received in each band into spectral amplitude data and sends them to the display unit for display.

[0010] As a preferred implementation: The sensor chip can collect spectral energy in six bands.

[0011] As a preferred implementation: The two double convex lenses are arranged in mirror image.

[0012] As a preferred implementation: The absolute value of the radius of curvature of the inner curved surface of the double convex lens located in the lens barrel is less than the absolute value of the radius of curvature of its outer curved surface located in the lens barrel.

[0013] As a preferred implementation: The diameter of the lens barrel is 15 mm, the diameter of the double convex lens is the same as that of the lens barrel, and the four curved surfaces of the two double convex lenses are 42.9 mm, -15.1 mm, 15.1 mm, and -42.9 mm respectively along the direction from the first conjugate point to the second conjugate point.

[0014] As a preferred implementation: The double convex lens is detachably mounted on the lens barrel.

[0015] As a preferred implementation: It further includes a connecting cylinder. The end of the lens barrel near the second conjugate point is provided with an external thread, and the connecting cylinder is provided with an internal thread. The connecting cylinder is threadedly connected to one end of the lens barrel near the second conjugate point;

[0016] An adjusting block is also threadedly connected inside the connecting cylinder. A turning rod is arranged on the outer side surface of the adjusting block. By turning the turning rod, the adjusting block is driven to rotate, and the sensor chip is arranged on the inner side surface of the adjusting block.

[0017] The present utility model also provides a citrus huanglongbing detection system for conjugate optical multispectral acquisition. For the detection device, the micro control unit is also electrically connected to a storage module and a data interface. The storage module is used to save spectral amplitude data and system codes, and the data interface is used to be electrically connected to an external computer.

[0018] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0019] By providing double convex lenses on both sides of the lens barrel in the present utility model to form a conjugate optical lens, the leaf sample to be detected is located at the first conjugate point of the optical lens, and the target surface of the sensor chip is provided at the second conjugate point. Thus, a certain optical axis angle can be set according to the actual situation, and the diameter and curvature radius of the double convex lens are designed according to the optical axis angle. Therefore, the light reflected on the leaf to be detected beyond this optical axis angle cannot enter the optical lens, while the light reflected within this optical axis angle range is refracted into parallel light by the first double convex lens and converged at the second conjugate point by the second double convex lens. Thus, the light with a larger optical axis angle is filtered out, avoiding interference, reducing signal fluctuations, and the energy is concentrated at one point, ensuring the utilization rate of energy. The sensor chip converts the collected light energy into an electric current signal, and after the electric current signal is quantified, a digital signal is generated to complete the generation of spectral data. Then, the amplitudes of the spectra at the central wavelengths of each band are recorded, and the amplitudes of the spectra of each band are compared with those of normal leaves respectively, so as to detect whether the citrus huanglongbing has been infected. The detection reliability is high, and the equipment cost is low. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of the conjugate optical lens part in the present utility model;

[0021] Figure 2 is a schematic diagram of the state when measuring the reflection spectrum in the present utility model;

[0022] Figure 3 is a partial cross-sectional view of the detection device in the present utility model;

[0023] Figure 4 is a schematic diagram of the connection relationship between the modules in the detection system of the present utility model.

[0024] In the figure, 1. lens barrel; 11. first conjugate point; 12. second conjugate point; 2. double convex lens; 21. first curved surface; 22. second curved surface; 23. third curved surface; 24. fourth curved surface; 3. sensor chip; 4. connecting cylinder; 5. adjusting block; 51. screwing rod; 6. leaf; 7. incident light; 8. reflected light. Detailed Embodiments

[0025] The following describes the embodiments of the present disclosure in detail with reference to the drawings.

[0026] The following specific examples illustrate the embodiments of the present disclosure. Those skilled in the art can easily understand other advantages and effects of the present disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without making creative efforts belong to the scope of protection of the present disclosure.

[0027] As Figure 1 and Figure 2 shown, a citrus huanglongbing detection device for conjugate optical multispectral acquisition includes a lens barrel 1 and two plano-convex lenses 2 arranged in parallel at both ends of the lens barrel. These three components form an optical lens. The two plano-convex lenses 2 are arranged mirror-symmetrically, thus forming a conjugate optical lens. The optical lens has two conjugate points, namely the first conjugate point 11 and the second conjugate point 12. The first conjugate point 11 is used to place the sample to be detected, that is, the leaf 6 in this embodiment, and the second conjugate point 12 is used to place the target surface of the sensor chip 3. Four curved surfaces are respectively provided on the two plano-convex lenses 2 from the direction of the first conjugate point 11 to the second conjugate point 12, which are the first curved surface 21, the second curved surface 22, the third curved surface 23, and the fourth curved surface 24.

[0028] The following provides a set of better data combinations: the distance between the first conjugate point 11 and the first plano-convex lens 2 is 20 mm, the thickness of both plano-convex lenses 2 is 3.5 mm, the distance between the two plano-convex lenses 2 is 42.8 mm, the distance from the second plano-convex lens 2 to the second conjugate point 12 is 17.5 mm, and the diameters of the plano-convex lenses 2 are both 15 mm. The radius of curvature of the first curved surface 21 is 42.9 mm, the radius of curvature of the second curved surface 22 is -15.1 mm, the radius of curvature of the third curved surface 23 is 15.1 mm, and the radius of curvature of the fourth curved surface 24 is -42.9 mm. The above data can be obtained through simulation and calculation. The purpose is to filter the light rays with a relatively large optical axis angle (the set optical axis angle in this embodiment is 20 degrees). As Figure 2 shown, due to the uneven surface shape of the leaf 6, its reflection form is diffuse reflection. The light rays with an optical axis angle greater than 20 degrees with respect to the optical lens cannot enter the plano-convex lens 2. The light rays with an optical axis angle within 20 degrees are refracted by the first plano-convex lens 2 into approximately parallel light, and then refracted by the second plano-convex lens 2 and converge at the second conjugate point 12. Thus, the redundant information of the light rays with a relatively large optical axis angle can be filtered, interference can be avoided, signal fluctuations can be reduced, and a relatively large amount of energy can be concentrated at the second conjugate point 12, improving the energy utilization rate.

[0029] As shown Figure 3 in the figure, as a preferred embodiment, two biconvex lenses 2 are connected to both ends of the lens barrel 1 by threads, which facilitates the replacement of the biconvex lenses 2. One end of the lens barrel 1 close to the second conjugate point 12 is provided with an external thread for fixing to the connecting cylinder 4 with an internal thread. An adjusting block 5 is also threadedly connected inside the connecting cylinder 4. A sensor chip 3 is installed on the inner side of the adjusting block 5, and a screwing rod 51 is integrally provided on the outer side. The operator can adjust the position of the target surface of the sensor chip 3 by rotating the screwing rod 51 to accurately position it at the second conjugate point 12. At the same time, the connecting cylinder 4 can play a role in shading to prevent external light interference and make the energy information collected by the sensor chip 3 more accurate.

[0030] The sensor chip 3 can collect energy in at least four bands. In order to make the differences between the bands more obvious, six bands are adopted in this embodiment, which are 610±10, 680±10, 730±10, 760±10, 810±10, 860±10 (unit: nm) respectively. When the optical signal irradiates the target surface of the sensor chip 3, the photoelectric effect occurs and the light energy is converted into current. After the current signal is quantized, a digital signal is generated, completing the generation of spectral data. The sensor chip 3 receives the instructions of the micro control unit and sends the spectral data to the micro control unit. The commands and data between the sensor chip and the micro control unit are all transmitted through the IIC (Inter-Integrated Circuit) bus. The micro control unit is also electrically connected to a human-machine interface. The main body of the human-machine interface is a display and a key, which can display the processed spectral data and input instructions for operation through the key.

[0031] After the spectral data is transmitted to the computer through the data interface, the central wavelengths of 6 bands, which are 610, 680, 730, 760, 810, and 860 (unit: nm) respectively, are extracted through an algorithm, and an analysis model is used to judge whether the measured sample is infected with huanglongbing. Taking the broadband spectrum as a reference value, for example, the amplitude of the 680nm wavelength reflected by a white screen is 100 units, and the amplitude of the 680nm wavelength reflected by the leaf 6 is 60 units, and the relative value of the leaf is obtained as 0.6. The amplitude values reflected by the white screen are different at different wavelengths. The relative values need to be calculated for all 6 wavelengths of 610, 680, 730, 760, 810, and 860nm, and then the differences in the relative values between the healthy leaf 6 and the diseased leaf are compared. The process of finding the relative values at different wavelengths is normalization. Taking the amplitude of the normalized reflection spectrum as an example, at 610 and 680nm, the diseased leaf is higher than the healthy leaf 6; at 730, 760, 810, and 860nm, the amplitude of the spectrum of the diseased leaf 6 is lower than that of the healthy leaf 6.

[0032] As shown Figure 4As shown in the figure, the present utility model also provides a citrus huanglongbing detection system for conjugate optical multispectral acquisition. The micro control unit is also electrically connected to a storage module and a data interface. The storage module consists of a 1MB NAND Flash memory and a 16M NOR Flash memory. The former is used to cache spectral data, and the latter stores the embedded system code.

[0033] The data interface extends from the microcontroller peripheral circuit, and its specific form is Mini-USB. After the spectral acquisition is completed, the computer is connected to the multispectral acquisition device through this interface to read the spectral data therein.

[0034] The micro control unit uses an STM32F103VC chip, which has a high cost performance and can expand relatively rich peripheral circuits. It is connected to the sensor chip 3, the human-machine interface, the storage unit, and the data interface.

[0035] The power supply module uses a rechargeable battery to provide the working voltage and current for the entire device.

[0036] The specific working process of the present utility model is as follows:

[0037] S1: Under sunny conditions, calibrate the normalization parameters of the outdoor calibration device. The calibration method is to align the optical lens of the detection device with the white reference screen, with the lens 2 cm away from the reference screen, and press the button according to the prompt on the liquid crystal screen to collect the broadband spectrum reflected by the reference screen.

[0038] S2: Align the lens of the device with the surface of the citrus plant leaf to be measured. The first double convex lens 2 is 6 cm away from the leaf, and press the button according to the prompt on the liquid crystal screen to collect the red light and near-infrared spectrum reflected by the leaf 6.

[0039] S3: Change to different positions to collect the red light and near-infrared spectrum reflected by different leaves.

[0040] S4: Transmit the collected spectral data to the computer through the Mini-USB data interface, and then obtain the amplitudes of the central wavelengths of six bands through the analysis algorithm and model, and compare with the healthy leaf 6 to judge the disease condition of the plant where the measured leaf is located.

[0041] The present utility model has at least the following advantages:

[0042] 1. Due to the adoption of the multispectral detection method, the sensor chip 3 receives the red light and near-infrared light information reflected by the citrus plant leaf 6, and judges the disease condition by analyzing the spectral data. Compared with the field manual diagnosis method and the laboratory pathological analysis method, this method has the advantages of non-contact, non-destructive, and objective evaluation.

[0043] 2. Since the method of using a conjugate optical lens to collect reflected light is adopted, the interference of stray light is reduced, and incident light from different directions is converged on the target surface of the sensor chip 3, making full use of the light energy, which brings the advantages of small data fluctuation and high light energy utilization rate.

[0044] 3. The embedded system design method is adopted to integrate the integrated circuit and the optical system into a portable terminal, and a rechargeable battery is used for power supply, which is suitable for real-time detection in the outdoor fields, bringing the advantages of convenient, fast, accurate data collection and low equipment cost.

[0045] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "middle", "length", "upper", "lower", "front", "rear", "vertical", "horizontal", "inner", "outer", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0046] In the present invention, unless otherwise clearly specified and limited, the first feature being "on" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. The meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically limited.

[0047] In the present invention, unless otherwise clearly specified and limited, the terms such as "mounted", "connected", "connected to", "fixed" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] The above is only to illustrate the embodiments of the present invention and is not intended to limit the present invention. For those skilled in the art, any modifications, equivalent replacements, improvements, etc. made without creative labor within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A citrus Huanglongbing detection device using conjugate optical multispectral acquisition, characterized in that: The invention comprises a conjugate optical lens composed of a lens barrel (1) and two biconvex lenses (2), wherein the two biconvex lenses (2) are arranged in parallel at two ends of the lens barrel (1), and the two conjugate points of the conjugate optical lens are respectively a first conjugate point (11) and a second conjugate point (12), a sample to be detected is located at the first conjugate point (11), and a target surface of a sensor chip (3) is arranged at the second conjugate point (12); The sensor chip (3) can collect spectral energy in at least four bands. The sensor chip (3) is electrically connected to a microcontroller unit, which is electrically connected to a display unit. The microcontroller unit converts the received spectral energy signals in each band into spectral amplitude data and sends the data to the display unit for display.

2. The citrus Huanglongbing detection device based on conjugate optical multi-spectral acquisition as claimed in claim 1, characterized in that: The sensor chip (3) can collect spectral energy in six bands.

3. The citrus Huanglongbing detection device based on conjugate optical multi-spectral acquisition as claimed in claim 1, characterized in that: The two biconvex lenses (2) are arranged in a mirror image.

4. The citrus Huanglongbing detection device based on conjugate optical multi-spectral acquisition as claimed in claim 3, characterized in that: The absolute value of the curvature radius of the curved surface of the biconvex lens (2) located on the inner side of the lens barrel (1) is smaller than the absolute value of the curvature radius of the curved surface of the biconvex lens (2) located on the outer side of the lens barrel (1).

5. The citrus Huanglongbing detection device based on conjugate optical multi-spectral acquisition as claimed in claim 4, characterized in that: The diameter of the lens barrel (1) is 15 mm, the diameter of the biconvex lens (2) is the same as that of the lens barrel (1), and the four curved surfaces of the two biconvex lenses (2) along the direction from the first conjugate point (11) to the second conjugate point (12) are 42.9 mm, -15.1 mm, 15.1 mm, and -42.9 mm respectively.

6. The citrus Huanglongbing detection device based on conjugate optical multi-spectral acquisition as claimed in claim 1, characterized in that: The biconvex lens (2) is detachably mounted on the lens barrel (1).

7. The citrus Huanglongbing detection device using conjugate optical multi-spectral acquisition as claimed in any one of claims 1 to 6, characterized in that: It also comprises a connecting tube (4), wherein the end of the lens barrel (1) close to the second conjugate point (12) is provided with an external thread, the connecting tube (4) is provided with an internal thread, and the connecting tube (4) is threadedly connected to the end of the lens barrel (1) close to the second conjugate point (12); The connection tube (4) is also threadedly connected to an adjustment block (5), and a screw rod (51) is provided on the outer side of the adjustment block (5). The adjustment block (5) is driven to rotate by screwing the screw rod (51), and the sensor chip (3) is arranged on the inner side of the adjustment block (5).

8. A citrus Huanglongbing detection system based on conjugate optical multi-spectral acquisition, characterized in that: The detection device comprises any one of claims 1 to 7, wherein the microcontroller unit is also electrically connected to a storage module and a data interface, the storage module is used to store spectral amplitude data and system code, and the data interface is used to electrically connect to an external computer.

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