A dynamic sensing method for large-area Raman scattering characteristics of chemical residues in meat

Abstract

The present invention relates to the field of Raman optical acquisition and analysis technology, and in particular to a dynamic sensing method for large-area Raman scattering characteristics of chemical residues in meat. In the present solution, an independently designed irregular agricultural product detection device is used to realize automatic tracking and focusing of the meat to be detected, and the coordinated movement of the detection device and the integrated probe is combined to quickly obtain the Raman scattering characteristics of the meat surface, complete the correction of the meat surface height, and comprehensively and accurately judge the chemical residue information of the meat as a whole and at each point. Compared with the traditional Raman scattering characteristic detection method, the present solution has the advantages of simple operation, accurate detection and high degree of automation.

Description

Technical Field

[0001] The present invention relates to the field of Raman optical collection and analysis technology, and in particular to a dynamic sensing method for large-area Raman scattering characteristics of chemical residues in meat. Background Art

[0002] Raman spectroscopy is a non-destructive, non-contact detection technology that can quickly obtain the chemical composition and structural information of samples. In recent years, Raman spectroscopy has been widely used in the field of food testing, and surface-enhanced Raman spectroscopy has been widely used to identify chemical residues in meat.

[0003] The traditional method of detecting the Raman scattering characteristics of chemical residues in meat requires multiple measurements at multiple locations on the meat, but the detection results are independent of each other in the case of multiple measurements. In addition, the acquisition of the Raman scattering characteristics of chemical residues in meat requires the use of an enhanced substrate to enhance the Raman scattering characteristic intensity of the chemical residues. The intensity of the Raman scattering characteristics of some chemical residues has a nonlinear relationship with the distance between the meat and the probe, and the traditional detection method cannot find a suitable excitation distance. In addition, the vertical height of each location on the upper surface of the meat is different, resulting in a different distance between each location and the probe, which affects the Raman light intensity during detection by the traditional detection method, and then affects the accuracy of the detection results. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a dynamic perception method for large-area Raman scattering characteristics of chemical residues in meat, which can quickly acquire the Raman scattering characteristics of the meat surface, complete the meat surface height correction, and comprehensively and accurately judge the chemical residue information of the meat as a whole and at each point by combining the coordinated movement of a meat detection platform and an integrated probe.

[0005] In order to solve the above technical problems, the technical solution provided by the present invention is as follows: the solution adopts the irregular agricultural product detection device designed by the present invention, the detection device comprises a horizontally placed sample holding platform which can be lifted and lowered and can rotate in a horizontal plane, and a horizontally movable integrated frame located above the sample holding platform, and the integrated frame is provided with a multiple light source optical fiber integrated assembly;

[0006] The method comprises the following steps:

[0007] (1) The staff places the meat to be tested on the sample holding platform, and at this time, the multiple light source optical fiber integrated assembly is located in the center of the sample holding platform;

[0008] (2) Start the test, the multiple light source optical fiber integrated assembly turns on the excitation light source, the sample holding platform starts to rise, and the relationship between the Raman light intensity of the chemical residues in the meat to be tested and the rising distance h at different distances is fitted. The fitting relationship curve is shown in the following formula:

[0009] y=α+βe -exp(ε-δh) #(1)

[0010] Wherein, h is the rising distance of the sample holding platform, y is the intensity of the light received at this distance, α is the full intensity noise value of the real-time change between the light source in the meat detection device and the meat to be tested at different distances, δ is the slope of the curve at this point, β is the maximum value of the estimated Raman intensity when h is the maximum, and ε is the interval width of the Raman light intensity change;

[0011] (3) The optimal detection distance is fixed; as the rising distance h increases to a certain value, when the Raman light intensity growth rate of the chemical residues in the meat is less than 1 / 10 of the maximum growth rate, the distance is set as the optimal detection distance h1. At this time, the multiple light source optical fiber integrated assembly takes the center point a of the sample holding platform as the center of the circle and the spacing of the Raman single light source optical fibers in the multiple light source optical fiber integrated assembly as the radius to perform a 360° Raman scattering characteristic signal scan on the meat to be tested;

[0012] (4) The multiple light source optical fiber integrated assembly moves horizontally, cooperates with the sample holding platform to rotate, completes the circular grid detection of the meat to be tested, and obtains the Raman scattering characteristics of any point of the meat to be tested;

[0013] (5) Assuming that the acquired Raman scattering characteristic signal X′ is 2r / p×2r / p, four dotted lines 1, 2, 3, and 4 are set on the sample holding platform. The size of the Raman scattering characteristic signal X′ is related to the minimum circumscribed square formed by the sample detection area, and its size is:

[0014]

[0015] Among them, i,j∈[1,1+2r / p], when x′ ij satisfy The corresponding calculation coefficient matrix M′ is (1+2r / p)×2πr / p×4, and 2πr / p spectral scattering characteristic function curves are obtained, thereby obtaining the chemical residue information in the meat at each point;

[0016] (6) Based on the obtained information on chemical residues in meat, let the value of the chemical residue information in meat at any point s of the tested meat be y(s), and let the value of the chemical residue information in meat at any point s′ on the circle with the resolution p of the Raman multi-light source as the radius be y(s)′. Let y(s)>y(s)′. If the distance relationship between s and s′ is consistent with Ds With D s′ The size relationship satisfies the following formula:

[0017]

[0018] Mark all points on the meat product that meet the conditions as the chemical residue concentration mutation area, where p is the resolution of the Raman multi-light source, and t is the chemical residue concentration mutation threshold parameter that can be changed according to the accuracy requirements. The higher t is, the lower the detection accuracy is, and vice versa.

[0019] (7) Move the light source to the area where the chemical residue concentration suddenly changes, and use the function curve of the distance between the chemical residue in the meat to be tested and the light source and the Raman light intensity to obtain the vertical height position h2 of each point in the area. Suppose the light intensity of the area where the chemical residue concentration suddenly changes before correction is y(s). After the surface height correction of the meat to be tested is completed, the light intensity of the area where the chemical residue concentration suddenly changes is y(s)+y(h2)-y(h1). According to the functional relationship between Raman light intensity and chemical residue concentration, the distribution result of the chemical residue in the meat to be tested is obtained.

[0020] Furthermore, the meat inspection device also includes a vertically arranged fixed slide column group and a threaded slide column, and the threaded slide column and the fixed slide column group are provided with a sample rotating motor and a fixed platform, and the sample rotating motor is transmission-connected to the sample holding platform.

[0021] Furthermore, a vertically arranged connecting column is connected to the top of the integrated frame, a slide rail is fixedly connected to the connecting column, and a transverse movement motor is transmission-connected to the slide rail. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0023] Figure 1 It is a structural schematic diagram of the irregular agricultural product detection device in this scheme;

[0024] Figure 2 10mg / kg pork ractopamine 635cm in this scheme -1 Schematic diagram of the relationship between the Raman light intensity at and the rising distance h of the sample holding platform 6;

[0025] Figure 3 This is a schematic diagram of the circular short dash trajectory of the scanning stroke in this scheme;

[0026] Figure 4 This is a schematic diagram of the scanning trajectory of a traditional Raman point light source;

[0027] Figure 5This is a comparison chart of the detection results of the traditional method and the detection method of this scheme;

[0028] In the figure: 1-lifting motor, 2-fixed sliding column group, 3-fixed platform, 4-threaded sliding column, 5-sample rotation motor, 6-sample rice serving platform, 7-integrated frame, 8-multiple light source optical fiber integrated assembly, 9-connecting column, 10-transverse movement motor, 11-slide rail. DETAILED DESCRIPTION

[0029] The preferred examples of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred examples described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0030] The dynamic sensing method of large-area Raman scattering characteristics of chemical residues in meat of the present invention adopts the following method: Figure 1 The irregular agricultural product meat detection device shown in the figure includes a vertically arranged fixed slide column group 2 and a threaded slide column 4, on which a sample rotating motor 5 and a fixed platform 3 are provided, the sample rotating motor 5 is transmission-connected to a horizontally arranged sample holding platform 6, and the bottom of the threaded slide column 4 is transmission-connected to a lifting motor 1.

[0031] An integrated frame 7 is provided above the sample holding platform 6, on which a multi-light source optical fiber integrated assembly 8 is provided. A vertically arranged connecting column 9 is connected to the top of the integrated frame 7, and a horizontally arranged slide rail 11 is fixedly connected to the connecting column 9, which is transmission-connected to a transverse movement motor 10.

[0032] In the above structural design, the fixed slide column group 2 and the threaded slide column 4 are fixed by the fixed platform 3, and the lifting motor 1 drives and controls the lifting of the threaded slide column 4 to adjust the height of the sample holding platform 6 in the vertical plane. The sample rotation motor 5 controls the rotation speed and angle of the sample holding platform 6. The traverse motor 10 controls the horizontal movement of the integrated frame 7, thereby adjusting the position of the multi-light source optical fiber integrated assembly 8 in the horizontal plane.

[0033] The dynamic perception method comprises the following steps:

[0034] (1) The staff places the meat to be tested on the sample holding platform 6 . At this time, the multiple light source optical fiber integrated assembly 8 is located in the center of the sample holding platform 6 .

[0035] (2) Start the test. The multiple light source optical fiber integrated assembly 8 turns on the excitation light source. The lifting motor 1 controls the sample holding platform 6 to rise slowly and uniformly from the lowest point of the threaded slide column 4. The relationship between the Raman light intensity of the chemical residue in the meat to be tested at different distances and the rising distance h of the sample holding platform 6 is fitted. The fitting relationship curve is shown in the following formula:

[0036] y=α+βe-exp(ε-δh) #(1)

[0037] Figure 2 Shows 635cm of ractopamine in 10mg / kg pork -1 The relationship between the Raman light intensity and the rising distance of the sample holding platform 6.

[0038] In the above formula, h is the rising distance of the sample holding platform 6, y is the intensity of the light received at this distance, α is the full intensity noise value of the real-time change between the light source in the meat detection device and the meat to be tested at different distances, δ is the slope of the curve at this point, β is the maximum value of the estimated Raman intensity when h is maximum, and ε is the interval width of the Raman light intensity change.

[0039] As the sample holding platform 6 rises, the light intensity increases rapidly. As the meat to be tested gradually approaches the probe, when the Raman light intensity growth rate is less than 1 / 10 of the maximum growth rate for the first time, this point is set as the light intensity deceleration point. In order to receive the maximum light intensity while ensuring that the sample does not contact the multi-light source optical fiber integrated assembly 8, the distance represented by this point is selected as the optimal detection distance. This process improves the shortcoming of fixed measurement distance in traditional methods and effectively optimizes the accuracy and stability of sample collection results.

[0040] Assuming that the fixed distance is h1, the multiple light source optical fiber integrated assembly 8 is Figure 3 The center point a of the sample holding platform 6 is taken as the center of the circle, and the spacing of the Raman single light source optical fibers in the multiple light source optical fiber integrated assembly 8 is taken as the radius to perform a 360° Raman scattering characteristic signal scan on the meat to be tested. In this embodiment, the scanning forms the following Figure 3 As shown in the circle and short dashed line trajectories b, c, d, and e.

[0041] (4) The multi-light source optical fiber integrated assembly 8 moves horizontally, and cooperates with the sample holding platform 6 to rotate 90 degrees to complete the circular grid detection of the meat to be tested, and obtain the Raman scattering characteristics of any point of the meat to be tested.

[0042] In the traditional Raman scattering feature processing flow, the radius of the sample holding platform is r, the maximum radius of the multi-light source fiber integrated assembly is also r, and the resolution of the Raman multi-light source is p. Therefore, the scanning trajectory of the traditional Raman point light source scattering feature is as follows: Figure 4 As shown by the dotted line 5, the traditional Raman point source scattering characteristic X = [x1,…,x i ,…x 1+2r / p ], where i∈[1, 1+2r / p]. The corresponding calculation coefficient matrix M is (1+2r / p)×2, and the linear function of the spectral scattering characteristics and the concentration of chemical residues in the meat is calculated.

[0043] (5) The Raman scattering feature processing flow in this scheme is:

[0044] Assume that the Raman scattering characteristic signal X′ is 2r / p×2r / p. The size of the Raman scattering characteristic signal X′ is related to the minimum circumscribed square of the sample detection area. The minimum circumscribed square is composed of four line segments 1, 2, 3, and 4. The size of the Raman scattering characteristic signal is:

[0045]

[0046] Among them, i,j∈[1,1+2r / p], when x′ ij satisfy The corresponding calculation coefficient matrix M′ is (1+2r / p)×2πr / p×4, and 2πr / p spectral scattering characteristic function curves are obtained, thereby obtaining the chemical residue information in the meat at each point;

[0047] (6) Based on the obtained information on chemical residues in meat, let the value of the chemical residue information in meat at any point s of the tested meat be y(s), and let the value of the chemical residue information in meat at any point s′ on the circle with the resolution p of the Raman multi-light source as the radius be y(s)′. Let y(s)>y(s)′. If the distance relationship between s and s′ is consistent with D s With D s′ The size relationship satisfies the following formula:

[0048]

[0049] Mark all points on the meat product that meet the conditions as the chemical residue concentration mutation area, where p is the resolution of the Raman multi-light source, and t is the chemical residue concentration mutation threshold parameter that can be changed according to the accuracy requirements. The higher t is, the lower the detection accuracy is, and vice versa.

[0050] (7) Move the light source to the area where the chemical residue concentration suddenly changes, and use the function curve of the distance between the chemical residue in the meat to be tested and the light source and the Raman light intensity to obtain the vertical height position h2 of each point in the area. Suppose the light intensity of the area where the chemical residue concentration suddenly changes before correction is y(s). After the surface height correction of the meat to be tested is completed, the light intensity of the area where the chemical residue concentration suddenly changes is y(s)+y(h2)-y(h1). According to the functional relationship between Raman light intensity and chemical residue concentration, the distribution result of the chemical residue in the meat to be tested is obtained.

[0051] Taking the 10mg / kg ractopamine sample in pork as an example, the Raman scattering characteristics before and after correction at 5 randomly selected positions were compared with the chemical residue concentration. The results are as follows: Figure 5 shown.

[0052] Compared with the traditional detection method, the measurement scheme proposed in this scheme can obtain 2πr / p spectral scattering characteristic functions, and the 0nm offset position is the center of the sample holding platform 6. The height of the center of the meat to be tested is used as the reference height, and the height of the remaining positions of the meat to be tested is corrected, which reduces the result fluctuations in the case of multiple tests on the same test sample. Therefore, compared with the traditional detection scheme, the accuracy of the results of this scheme is significantly improved.

[0053] Finally, it should be noted that the above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A dynamic sensing method for large-area Raman scattering characteristics of chemical residues in meat, characterized in that: The method adopts a meat detection device, which includes a horizontally placed sample holding platform that can be raised and lowered and can rotate in a horizontal plane, and a horizontally movable integrated frame located above the sample holding platform, wherein a multiple light source optical fiber integrated component is provided on the integrated frame; The method comprises the following steps: (1) The staff places the meat to be tested on the sample holding platform, and at this time, the multiple light source optical fiber integrated assembly is located in the center of the sample holding platform; (2) Start the test, the multiple light source optical fiber integrated assembly turns on the excitation light source, the sample holding platform starts to rise, and the relationship between the Raman light intensity of the chemical residues in the meat to be tested and the rising distance h at different distances is fitted. The fitting relationship curve is shown in the following formula: y=α+βe -exp(ε-δh) Wherein, h is the rising distance of the sample holding platform, y is the intensity of the light received at this distance, α is the full intensity noise value of the real-time change between the light source in the meat detection device and the meat to be tested at different distances, δ is the slope of the curve at this point, β is the maximum value of the estimated Raman intensity when h is the maximum, and ε is the interval width of the Raman light intensity change; (3) The optimal detection distance is fixed; as the rising distance h increases to a certain value, when the Raman light intensity growth rate of the chemical residues in the meat is less than 1 / 10 of the maximum growth rate, the distance is set as the optimal detection distance h1. At this time, the multiple light source optical fiber integrated assembly takes the center point a of the sample holding platform as the center of the circle and the spacing of the Raman single light source optical fibers in the multiple light source optical fiber integrated assembly as the radius to perform a 360° Raman scattering characteristic signal scan on the meat to be tested; (4) The multiple light source optical fiber integrated assembly moves horizontally, cooperates with the sample holding platform to rotate, completes the circular grid detection of the meat to be tested, and obtains the Raman scattering characteristics of any point of the meat to be tested; (5) Assuming that the acquired Raman scattering characteristic signal X' is 2r / p×2r / p, four dot-dashed lines 1, 2, 3, and 4 are set on the sample holding platform. The size of the Raman scattering characteristic signal X' is related to the minimum circumscribed square formed by the sample detection area, and its size is: Among them, i,j∈[1,1+2r / p], when x' ij satisfy The corresponding calculation coefficient matrix M' is (1+2r / p)×2πr / p×4, and 2πr / p spectral scattering characteristic function curves are obtained, thereby obtaining the chemical residue information in the meat at each point; (6) Based on the obtained information on chemical residues in meat, let the value of the chemical residue information in meat at any point s of the tested meat be y(s), and let the value of the chemical residue information in meat at any point s' on the circle with the resolution p of the Raman multi-light source as the radius be y(s)'. Let y(s)>y(s)'. If the distance relationship between s and s' is consistent with D s With D s' The size relationship satisfies the following formula: Mark all points on the meat product that meet the conditions as the chemical residue concentration mutation area, where p is the resolution of the Raman multi-light source, and t is the chemical residue concentration mutation threshold parameter that can be changed according to the accuracy requirements. The higher t is, the lower the detection accuracy is, and vice versa. (7) Move the light source to the area where the chemical residue concentration suddenly changes, and use the function curve of the distance between the chemical residue in the meat to be tested and the light source and the Raman light intensity to obtain the vertical height position h2 of each point in the area. Suppose the light intensity of the area where the chemical residue concentration suddenly changes before correction is y(s). After the surface height correction of the meat to be tested is completed, the light intensity of the area where the chemical residue concentration suddenly changes is y(s)+y(h2)-y(h1). According to the functional relationship between Raman light intensity and chemical residue concentration, the distribution result of the chemical residue in the meat to be tested is obtained.

2. The method for dynamic perception of large-area Raman scattering characteristics of chemical residues in meat according to claim 1, characterized in that: The meat inspection device also includes a vertically arranged fixed slide column group and a threaded slide column, the threaded slide column and the fixed slide column group are provided with a sample rotating motor and a fixed platform, the sample rotating motor is transmission-connected to the sample holding platform, and the bottom of the threaded slide column is transmission-connected to a lifting motor.

3. The method for dynamic perception of large-area Raman scattering characteristics of chemical residues in meat according to claim 1, characterized in that: The top of the integrated frame is connected with a vertically arranged connecting column, the connecting column is fixedly connected with a slide rail, and the slide rail is transmission-connected with a transverse movement motor.

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