Intelligent selection method and pile-leveling equipment for Longjing tea based on image contour analysis

Abstract

The present invention discloses a Longjing tea selection method and stacking equipment based on image profile analysis, belonging to the technical field of intelligent manufacturing equipment. The stacking equipment includes: a loading mechanism for loading various types of pre-selected Longjing tea into corresponding loads; a mixing mechanism for evenly mixing and flattening the pre-selected Longjing tea from the multiple loading mechanisms; an impurity removal mechanism for removing impurities from the pre-selected Longjing tea after being processed by the mixing mechanism; and a selection mechanism for finely sorting the pre-selected Longjing tea by visual photography. The present invention also includes a Longjing tea selection method based on image profile analysis, which uses image profile analysis to select premium Longjing tea.

Description

Technical Field

[0001] The present invention relates to intelligent manufacturing equipment, and in particular to a Longjing tea selection method and stacking equipment based on image profile analysis. Background Art

[0002] Longjing tea is renowned for its emerald green color, beautiful shape, rich fragrance, and mellow flavor. Its unique "light and distant" and "fragrant and clear" aroma and exceptional quality set it apart from other teas. Longjing tea is a specialty of Zhejiang Province and a national geographical indication product in China. Premium Longjing tea is flat, smooth, and upright, with a lustrous, tender green color, a fresh, refreshing aroma, a refreshing, mellow flavor, and delicate, petal-shaped leaves.

[0003] The production of Longjing tea (flat tea), particularly West Lake Longjing tea, typically involves a rough processing workshop (roasting) and a refining workshop (screening and leveling), with the refining workshop being the primary technical area. The refining workshop's primary tasks involve screening, grading, leveling, and removing impurities from the roasted dry tea leaves to produce a tea product of consistent quality. While screening, grading, and impurity removal are relatively simple, leveling is a complex process that is crucial to product quality stability.

[0004] Heaping is the process of evenly mixing tea leaves of the same grade but different origins, picking times, and batches according to different indicators such as taste, aroma, and color, in order to reduce the quality differences between different batches of tea and achieve relatively stable quality.

[0005] Selection involves meticulously sorting the tea leaves from the pile based on technical indicators such as size, shape, color, luster, and clarity. Finished Longjing tea is classified into six basic categories: special grade and grades one through five. The special grade standard requires appearance: flat and smooth, straight and pointed; tender green and fresh; uniform and heavy; and clean.

[0006] Therefore, in order to improve the quality of Longjing tea and carry out its selection and classification operations, it is necessary to conduct better research and application to make it more accurate, standardized and efficient. Summary of the Invention

[0007] The purpose of the present invention is to provide a Longjing tea selection method and stacking equipment based on image contour analysis, which is used to improve the stacking efficiency of Longjing tea and accurately sort it through efficient stacking and image recognition, while reducing damage to the Longjing tea during the sorting process.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows:

[0009] A stacking device, comprising:

[0010] The loading mechanism is used to load various types of pre-selected Longjing tea into the corresponding materials;

[0011] A mixing mechanism, for uniformly mixing and spreading the pre-selected Longjing tea from the multiple feeding mechanisms;

[0012] The impurity removal mechanism is used to remove impurities from the pre-selected Longjing tea after being processed by the mixing mechanism;

[0013] A selection mechanism, which performs fine sorting operations on the pre-selected Longjing tea by visual photography;

[0014] The feeding mechanism includes a plurality of feeding hoppers, a feeding conveyor belt is arranged below the feeding hopper, and a vibrating conveying mechanism is arranged at the front end of the conductive feeding mechanism, and the front end of the vibrating conveying mechanism has a 45-degree bevel lead-out outlet; the mixing mechanism includes a transverse conveyor belt, which is arranged below the bevel lead-out outlet of the vibrating conveyor mechanism, and the width of the transverse conveyor belt matches the size of the bevel lead-out outlet; the impurity removal mechanism is arranged at the rear end of the transverse conveyor belt, which includes a plurality of electrostatic adsorption components and an impurity removal conveyor belt, and the impurity removal conveyor belt is arranged below the electrostatic adsorption component; the selection mechanism includes a plurality of selection conveyor belts, the front end of the selection conveyor belt is used to receive the pre-selected Longjing tea from the rear end of the impurity removal conveyor belt, a camera is arranged at a fixed position directly above the selection conveyor belt, the camera is used to shoot the Longjing tea directly below it, the camera is connected to a control host, an air nozzle is provided at a fixed position on one side of the selection conveyor belt behind the camera, a first collection box is provided on the opposite side of the air nozzle, the air nozzle is connected to an air source and a valve, the valve is connected to the control host, and a second collection box is provided at the end of the selection conveyor belt.

[0015] Furthermore, the loading conveyor belt is made of a flexible material, and its conveying surface has a plurality of grooves, and a uniform mechanism is provided in the middle of the loading conveyor belt.

[0016] Furthermore, the uniformity mechanism is used to spread the pre-selected Longjing tea evenly onto the conveying surface of the loading conveyor belt. The uniformity mechanism includes a horizontal cross bar and a plurality of staggered rollers arranged on the cross bar. A motor is arranged at one end of the horizontal cross bar, and a flexible scraper is arranged at the end of the cross bar.

[0017] Furthermore, the vibrating conveying mechanism includes a vibrating plate and a vibrating mechanism arranged below the vibrating plate. The vibrating plate is connected to the frame through multiple elastic parts. The rear end of the vibrating plate matches the output port of the loading conveyor belt, and the front end of the vibrating plate is a 45-degree bevel output port.

[0018] Furthermore, the electrostatic adsorption component includes an electrostatic adsorption roller and an electrostatic adsorption roller motor spanning the top of the impurity removal conveyor belt. The electrostatic adsorption roller is connected to a high-voltage electrostatic generator, and the surface of the electrostatic adsorption roller is uniformly charged with static electricity. Sliders are arranged at both ends of the electrostatic adsorption roller, and the sliders are equipped with vertical slide grooves. The sliders are connected to a servo cylinder, and the servo cylinder is used to drive the slider and the electrostatic adsorption roller to rise and fall along the slide groove, and to adjust the distance between the electrostatic adsorption roller and the upper surface of the impurity removal conveyor belt.

[0019] Furthermore, a foreign matter collection mechanism is arranged behind the electrostatic adsorption roller in the direction of rotation. The foreign matter collection mechanism includes a scraper adhered to the surface of the electrostatic adsorption roller, and a U-shaped groove located on one side below the scraper and fixedly connected to the slider. A screw conveyor is arranged in the U-shaped groove, and the screw conveyor is used to continuously discharge impurities accumulated in the U-shaped groove along its axial direction.

[0020] Furthermore, a plurality of funnel-shaped material collecting structures are arranged at the rear end of the impurity removal conveyor belt, and an inclined guide plate is arranged in front of the funnel-shaped material collecting structure. The lower end of the guide plate is arranged above the front end of the selection conveyor belt. The running speed of the selection conveyor belt is greater than the running speed of the impurity removal conveyor belt. The selection conveyor belt is a conveyor belt structure with a light-colored bottom plate.

[0021] A Longjing tea selection method based on image profile analysis is applied to the above-mentioned stacking device, comprising the following steps:

[0022] S1 uses the camera to shoot the Longjing tea at the current position on the selected conveyor belt, obtains the current image and sends it to the control host;

[0023] S2 performs pixel positioning on the Longjing tea image in the current photo, calculates the number of pixels corresponding to the longest diagonal line based on the number of pixels in the X-axis direction and the Y-axis direction, and determines the length of the current Longjing tea based on the pixel number value and a preset relationship between pixels and length. If the length value is not within the set length range, the current Longjing tea is marked as "no";

[0024] S3: If the length of the current Longjing tea is within the set length range, perform sub-pixel edge detection on the current photo, construct and sample pixel points at specific intervals, connect adjacent pixel sampling points, and construct a closed graph consisting of pixel sampling points and connecting lines. The longest diagonal of the graph space is used as the Y axis, and the rear end of the Y axis is used as the coordinate origin. All pixel sampling points are placed in the coordinate system, and several adjacent pixel sampling points on the left and right are connected at the vertex of the Y axis to fit a triangular structure. If the vertex angle of the triangular structure is greater than a preset value, mark the current Longjing tea as "no".

[0025] S4: If the vertex angle of the triangle structure is less than or equal to a preset value, perform acute angle search processing on at least three adjacent pixel sampling points, determine the current acute angle point, connect the acute angle point with the coordinate origin, divide the closed figure into two parts, and calculate the area of ​​the enclosed interval of the corresponding pixel sampling points. If the area ratio of the small area part to the large area part is greater than the preset value, mark the current Longjing tea as "no".

[0026] S5: If the area ratio of the small area portion to the large area portion is less than or equal to a preset value, find the endpoint of the longest side in the outline of the small area portion as a vertex, connect the vertex with the origin, and if the angle between the connecting line and the Y axis is greater than the set value, mark the current Longjing tea as "no";

[0027] S6 marks the current Longjing tea as "yes", calculates the distance deviation between the current position of the Longjing tea and the jet position of the jet nozzle, and calculates the time required for the Longjing tea to move the distance based on the running speed value of the selection conveyor belt. When the time value is reached, the jet nozzle is operated to jet by controlling the valve, and the current Longjing tea marked as "yes" is driven to the first collection box.

[0028] Furthermore, in step S5, if the ratio of the length of the diagonal line of the small area portion to the length of the longest diagonal line is greater than a preset value, the current Longjing tea is marked as "no".

[0029] Furthermore, in any one of steps S2 to S5, if the current Longjing tea has been marked as "no", the process returns to step S1, and the next Longjing tea to be identified on the selection conveyor belt is used as the current Longjing tea.

[0030] Compared with existing technologies, this solution has the following advantages:

[0031] This solution provides a stacking device, in which a loading mechanism can realize the loading of multiple categories of pre-selected Longjing tea, and carry out differentiated loading operations in a reasonable, orderly and set mixing ratio on time according to the corresponding characteristics of these Longjing teas. At the same time, this solution has multiple loading mechanisms, which can perform various combined loading and stacking operations according to set requirements, and ultimately can implement the stacking operation of Longjing tea flexibly and efficiently;

[0032] In order to make the stacking operation more uniform, this solution adopts the method of secondary vibration conveying, and uses the transverse conveyor belt to flatten and stack the primary selected Longjing tea delivered by all the feeding mechanisms and perform vibration mixing operations, so the back-end product has excellent consistency;

[0033] This solution uses electrostatic adsorption to remove foreign matter such as dust, powder, lint, or fine particles from the pre-selected Longjing tea. This can improve the purity of the Longjing tea, reduce the impact of such foreign matter on subsequent selection operations, and improve the stability of equipment operation.

[0034] The selection operation of this solution is mainly carried out by the image contour analysis method of visual recognition. Since Longjing tea is a flat tea, it is always placed on the conveyor belt with both sides facing forward and backward. Therefore, this method can fully utilize the characteristics of the flat tea and greatly improve the recognition efficiency and accuracy. It can also reduce the system calculation amount and improve the overall recognition efficiency.

[0035] As the visual recognition method of this scheme, Longjing tea is photographed vertically downward by a camera. Due to the fixed height, the length of the current Longjing tea can be quickly deduced through the number of pixels corresponding to the current Longjing tea in the image. Therefore, according to the Longjing tea grade standard, the current Longjing tea can be quickly predicted, thereby greatly improving efficiency; this scheme will also adopt sub-pixel edge detection operations, and through pixel sampling, the outline of the current Longjing tea will be polygonized, thereby realizing a variety of subsequent recognition and comparison operations; in this scheme, through feature analysis of special-grade Longjing tea, including technical features such as length, top shape, enclosed area ratio, angle and branch length, special-grade Longjing tea can be accurately distinguished and identified, which can solve the problem of traditional manual participation and reduce damage to Longjing tea during the selection operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the overall structure of a preferred embodiment.

[0037] Figure 2 This is the rear-end structural layout diagram of the six loading mechanisms.

[0038] Figure 3 It is a structural diagram of the feeding mechanism.

[0039] Figure 4 It is a schematic diagram of the overall structure of the impurity removal mechanism and the selection mechanism.

[0040] Figure 5 Schematic diagram of the structural decomposition of the electrostatic adsorption component.

[0041] Figure 6 Schematic diagram of the structure of the selected organization.

[0042] Figure 7 It is a side structural diagram of the selected mechanism.

[0043] Figure 8 Schematic diagram of the structural layout of a single selected mechanism.

[0044] Figure 9This is a table chart of Longjing tea grading standards.

[0045] Figure 10 These are actual pictures of typical premium Longjing tea in dry and wet form.

[0046] Figure 11 Schematic diagram of Longjing tea image recognition processing.

[0047] Figure 12 Schematic diagram of the different structures of Longjing tea. DETAILED DESCRIPTION

[0048] West Lake Longjing tea, particularly pre-Mingqian (picked and produced before the Qingming Festival), is the highest-grade and most valuable Longjing tea. Hangzhou's Xihu District is the most important origin of West Lake Longjing tea, and its value is exemplified by the rigorously standardized production, leveling, and selection of West Lake Longjing tea. West Lake Longjing tea is a product that demands high quality. The applicant of this proposal is committed to promoting and selling Longjing tea domestically and internationally. To achieve greater product consistency, this proposal aims to standardize its production, leveling, and selection processes. While inheriting and developing historical techniques, this proposal utilizes modern technology to preserve details such as its shape, color, and appearance during the selection process, ensuring more standardized and accurate grading.

[0049] refer to Figure 1 (In this figure, the conveyor belt and its supporting wheels, supporting structure, driving structure, and other auxiliary structures have been hidden for clarity.) A stacking device for intelligent selection of Longjing tea includes:

[0050] The feeding mechanism 1 is used for loading various types of pre-selected Longjing tea into the corresponding feeding operation;

[0051] A mixing mechanism 2, which is used to evenly mix and spread the pre-selected Longjing tea from the multiple feeding mechanisms;

[0052] The impurity removal mechanism 3 is used to remove impurities from the pre-selected Longjing tea after being processed by the mixing mechanism;

[0053] The selecting mechanism 4 performs fine sorting operations on the pre-selected Longjing tea by visual photography;

[0054] The control host is connected to the above-mentioned electrical equipment, can analyze and process the image, control the corresponding electrical components, and achieve overall coordinated and precise operation.

[0055] refer to Figure 2 Figure 3The feeding mechanism 1 includes a plurality of feeding hoppers 11, and a feeding conveyor belt 12 is arranged correspondingly below the feeding hoppers 11. In this embodiment, by arranging six feeding mechanisms 1 side by side, the pre-selected Longjing tea of ​​the same grade but different origins, picking times, and batches can be arranged in different feeding hoppers 11 according to different indicators such as taste, aroma, and color, and evenly mixed to reduce the quality differences of tea leaves between different batches and achieve relative stability of quality. The six feeding ports of the stacking equipment can all be independently controlled in speed, and the stacking data can be set according to different needs to meet the stacking requirements of different products. It should be noted that when the pre-selected Longjing tea is placed in the loading hopper 11, it has already undergone operations such as multi-layer screening and air blowing to remove impurities such as dust, mud or tea stems, so that the subsequent processing efficiency can be improved.

[0056] Specifically, the loading conveyor belt 12 is in an inclined upward conveying state. In order to improve the conveying capacity, the loading conveyor belt 12 is made of flexible material, and its conveying surface has multiple grooves 13. The grooves 13 can increase the friction of the preliminary Longjing tea conveyed upward and make the conveying more balanced. A uniform mechanism is provided at the front end of the loading hopper 11, that is, in the middle of the loading conveyor belt 12. The uniform mechanism is used to spread the preliminary Longjing tea evenly on the conveying surface of the loading conveyor belt 12 and maintain a reasonable thickness. The uniform mechanism includes a horizontal cross bar 14 and a plurality of staggered rollers 15 arranged on the cross bar. A motor is arranged at one end of the horizontal cross bar 14. The motor realizes its corresponding rotation speed under the control of the control host. In order to protect the preliminary Longjing tea and prevent it from being damaged, a flexible sheet 141 is arranged at the end of the cross bar 14.

[0057] The front end of the feeding conveyor belt 12 is provided with a vibrating conveying mechanism, which includes a vibrating plate 16 and a vibrating mechanism arranged below the vibrating plate. The vibrating plate 16 is connected to the frame through a plurality of elastic members 17. In some embodiments, the elastic member can be a flexible connecting rubber tube or a pneumatic tube structure, or a spring limit support structure (such as Figure 3 (as shown) a vibration unit is arranged below the vibration plate 16. In some embodiments, the vibration unit can be an eccentric wheel structure driven by a motor. When the motor drives the eccentric wheel to rotate, it will realize the vibration of the vibration plate 16 with a specific frequency and amplitude according to the rotation speed of the eccentric wheel. Therefore, the primary selected Longjing tea (based on the flat state) on the vibration plate 16 can be vibrated and transported forward, and in the process of vibration transportation, the primary selected Longjing tea can be spread more evenly and uniformly. The front end of the vibration plate is a 45-degree beveled edge outlet.

[0058] The mixing mechanism 2 is arranged below the front end of the vibrating plate 16 and includes a transverse conveyor belt 21. The transverse conveyor belt 21 is arranged below the opening of the vibrating plate 16, and the width of the transverse conveyor belt 16 matches the size of the opening of the vibrating plate 16. Therefore, the pre-selected Longjing tea that has been vibrated and conveyed can be transferred to the transverse conveyor belt 21 at the opening in front of the vibrating plate 16. Due to the 45-degree opening, the pre-selected Longjing tea can be transferred to the transverse conveyor belt 21 to maintain its original balanced and flat state without stacking.

[0059] The transverse conveyor belt 21 can receive different Longjing teas conveyed by six feeding mechanisms 1 arranged side by side. After passing through the six feeding mechanisms 1, the primary Longjing teas conveyed by the six feeding mechanisms 1 are evenly stacked and mixed at the rear end of the transverse conveyor belt 21.

[0060] A second vibrating conveying mechanism 22 is arranged at the rear end of the transverse conveyor belt 21. The second vibrating conveying mechanism 22 can have a similar structure to the vibrating conveying mechanism. The front end of the second vibrating conveying mechanism 22 is a straight output port. When the mixed primary Longjing tea is conveyed to the second conveying member 22, during its vibrating conveying process, the primary Longjing tea can be more evenly mixed and staggered to achieve even distribution operation.

[0061] refer to Figure 4 Figure 5 The impurity removal mechanism 3 is arranged at the rear end of the second vibrating conveying mechanism 22. The impurity removal mechanism 3 includes multiple electrostatic adsorption components 31 and an impurity removal conveyor belt 30. It removes dust, powder, lint or fine particles in the pre-selected Longjing tea by electrostatic adsorption, making the finished Longjing tea cleaner and facilitating subsequent selection operations.

[0062] The electrostatic adsorption component 31 includes an electrostatic adsorption roller 32 and an electrostatic adsorption roller motor 33 that spans the top of the dust removal conveyor belt 31. The electrostatic adsorption roller 33 is electrically connected to the electrostatic generating unit, and its surface has a coating or outer ring layer that can accommodate static electricity, so the surface of the electrostatic adsorption roller 33 can be uniformly provided with static electricity. Sliders 34 are arranged at both ends of the electrostatic adsorption roller 33. The slider 34 is equipped with a vertical slide groove 35. A servo cylinder 36 is provided on the slider 35. The servo cylinder 36 can adjust the vertical height of the slider 35 and the electrostatic adsorption roller 33, and is used to adjust the distance between the electrostatic adsorption roller 33 and the upper surface of the dust removal conveyor belt 30, thereby realizing the adsorption and transfer operation of foreign matter such as dust, dust, lint or fine particles on the dust removal conveyor belt 30, so that it is adsorbed and adsorbed to the surface of the electrostatic adsorption roller 33.

[0063] In order to collect foreign matter on the surface of the electrostatic adsorption roller 33, enable it to operate continuously and efficiently, and prevent secondary pollution, a foreign matter collection mechanism is arranged at the rear end of the rotation of the electrostatic adsorption roller 33. The foreign matter collection mechanism includes a scraper 37 attached to the surface of the electrostatic adsorption roller 33 and a U-shaped groove 38 arranged on one side below the scraper. The U-shaped groove 38 is integrally connected to the slider 35 through a connecting piece, and can realize synchronous up and down displacement movement with the electrostatic adsorption roller 33 under the action of the servo cylinder 36. A screw conveyor 39 is arranged in the U-shaped groove. Under the action of the motor on one side of the screw conveyor 39, through its own rotation, the impurities and foreign matter collected by the scraper 33 in the U-shaped groove 38 can be output from the continuous output pipe at one end thereof.

[0064] In actual operation, multiple electrostatic adsorption components 31 can be arranged side by side, and differentiated heights and electrostatic voltages can be set to make the collection of foreign matter and impurities more complete and efficient.

[0065] refer to Figure 6 Figure 7 Figure 8 The selecting mechanism 4 includes multiple selecting conveyor belts 40, which are used to receive the pre-selected Longjing tea from the impurity removal conveyor belt 30. In order to reduce external influences, the selecting mechanism 4 is arranged with a shielding cover 401. As a single selecting conveyor belt 40, a camera 41 is arranged at a fixed position just above its front end. The camera 41 is used to shoot the Longjing tea on the selecting conveyor belt 40 just below it. The camera 41 is connected to the control host. The control host receives the image shot by the camera 41, analyzes and processes it, and configures the corresponding result to the corresponding equipment. An air nozzle 45 is provided at a fixed position on one side of the selecting conveyor belt 40 at the rear end of the camera 41, and a first collecting box 44 is provided on the opposite side of the air nozzle 45. In order to prevent interference with air flow, a ventilation net is provided on the side wall of the first collecting box 44. The air nozzle 45 is connected to an air source and a valve. The valve is connected to the control host and, under the control of the control host, realizes precise air jet operation. A second collecting box is provided at the rear end of the selecting conveyor belt 40.

[0066] A plurality of funnel-shaped material collecting structures 301 are arranged at the rear end of the impurity removal conveyor belt 30. The material collecting structures 301 correspond one-to-one to the selection conveyor belt 40. A guide plate 302 is arranged between the material collecting structure 301 and the selection conveyor belt 40. The front end of the guide plate 302 is arranged in contact with the turning point of the impurity removal conveyor belt 30, and can receive the pre-selected Longjing tea from the impurity removal conveyor belt 30 and transfer it to the front end of the selection conveyor belt 40 in a translational manner. At the same time, under the control of the control host, the running speed of the selection conveyor belt 40 is greater than the running speed of the impurity removal conveyor belt 30, so that the transportation of the pre-selected Longjing tea can be controlled and the tea can be in a flat structure at the selection conveyor belt 40, and there will be no situation where two pieces of Longjing tea are stacked.

[0067] In order to improve the recognition efficiency of the camera 41, soft light components 42 are arranged on both sides of the camera 41 to provide shadowless soft light for the camera; in order to make the green Longjing tea better appear on the selection conveyor belt 40, the selection conveyor belt 40 is a conveyor belt structure with a light-colored bottom plate; in order to reduce the adhesion of debris, a blowing component 43 is arranged at the lower position of the rotation of the selection conveyor belt 40, which is used to use blowing air flow to make the surface of the selection conveyor belt 40 clean and free of foreign matter.

[0068] In order to improve the imaging comparison efficiency of the camera 41 and facilitate the distance calibration of the current Longjing tea, a substrate 47 is provided directly below the camera 41 and on both sides or below the selection conveyor belt 40. A mark 48 is provided at the midline position of the substrate 47. The mark is a fixed physical mark drawn or pasted on the substrate 47. The mark 48 is aligned vertically with the camera 41. The mark 48 can be a line segment structure. The length of the line segment of the mark 48 is a fixed value, which is used for reference comparison during imaging. In order to reduce interference between adjacent selection conveyor belts 40, partitions 49 are provided on both sides of the substrate 47.

[0069] On the other hand, the present solution also includes a Longjing tea selection method based on image contour analysis, which is applied to the above-mentioned equalizing equipment.

[0070] refer to Figure 9 Figure 10 As the grading standard of West Lake Longjing tea, the quality of fresh leaves, among which the special grade is: one bud and one leaf just beginning to unfold, the angle between the bud and the leaf is small, the bud is longer than the leaf, the bud and the leaf are all even and strong, and the bud and leaf length does not exceed 2.5 cm; the first grade: one bud and one leaf to one bud and two leaves just beginning to unfold, mainly one bud and one leaf, the rate of one bud and two leaves just beginning to unfold is less than 10%, the bud is slightly longer than the leaf, all are clean, and the bud and leaf length does not exceed 3 cm. The special grade standard of Longjing tea (finished product) requires the appearance: flat and smooth, straight and sharp; tender green and fresh; even and heavy; all are clean. Typical special grade Longjing tea (finished product) is as follows Figure 12 As shown in M1.

[0071] Based on the above standards, this solution uses image contour analysis to select premium Longjing tea, including the following steps:

[0072] S1 uses the camera to take a picture of the current Longjing tea at the current location, obtains the current photo, and sends it to the control host.

[0073] S2 performs pixel positioning on the Longjing tea image in the current photo, calculates the number of pixels corresponding to the longest diagonal line based on the number of pixels in the X-axis direction and the Y-axis direction, and determines the length of the current Longjing tea based on the pixel number value and a preset relationship between pixels and length. If the length value is not within the set length range, the current Longjing tea is marked as "no";

[0074] Specifically, refer to Figure 11 In the area in the image, after the Longjing tea is imaged, since the camera 42 is located at a fixed position height of the current Longjing tea, its pixel structure is like the grid structure in the figure (in order to make the image clearer, a grid is constructed for multiple pixels in the figure, the same below), so according to the number of pixels in the X-axis and Y-axis directions, the length of the hypotenuse of the triangle corresponding to the current Longjing tea can be calculated through simple technology (as shown in the red frame), and then the length value of the current Longjing tea can be quickly calculated. Under normal circumstances, the length range of the premium West Lake Longjing tea should be between 1.5-2.5, so the current Longjing tea outside the range can be quickly marked as "no".

[0075] S3: If the length of the current Longjing tea is within the set length range, perform sub-pixel edge detection on the current photo, construct and sample pixel points at specific intervals, connect adjacent pixel sampling points, and construct a closed graph consisting of pixel sampling points and connecting lines;

[0076] Specifically, refer to Figure 11 In the second and third areas of the second area, through the sub-pixel edge detection operation, 13 pixel sampling points are sampled from P01 to P13 on the edge of the current Longjing tea (13 sampling points are used to make the image clearer. In actual sampling, the number of pixel sampling points can be far more than 13). Then, the P01-P13 sampling points are placed in the coordinates. In order to make the calculation clearer and more convenient, point P01 can be set as the coordinate origin, so the coordinates of the P01-P13 sampling points can be obtained.

[0077] In order to improve computing and processing efficiency, in some embodiments, the longest diagonal line of the graphic space can be used as the Y axis, and the rear end of the Y axis can be used as the coordinate origin. All pixel sampling points can be placed in the coordinate system, and several adjacent pixel sampling points on the left and right sides can be connected at the vertex of the Y axis to fit into a triangular structure. If the vertex angle of the triangular structure is greater than a preset value, the current Longjing tea is marked as "no";

[0078] Specifically, the sampling points P01-P13 are sequentially connected to form a vector contour map as shown in the third area. In this step, the focus is on detecting whether the tip of the current Longjing tea bud is missing or broken. The typical situation corresponds to Figure 12As shown in M2, the red line represents the defect of the tip of the bud. Although M2 meets the length range of premium Longjing tea in step S2, it does not belong to premium Longjing tea. In this step, select sampling point P07 and connect the corresponding sampling points P06 and P08 in sequence. By calculating the angle formed by P06-P07-P08, if the angle is less than 65 degrees, it can be regarded as the tip is complete, otherwise the current Longjing tea is marked as "no".

[0079] S4: If the vertex angle of the triangle structure is less than or equal to the preset value (which can be 65 degrees), perform acute angle search processing on at least three adjacent pixel sampling points. This operation is used to find the P09 sampling point in the third area diagram, connect the acute angle point with the coordinate origin, and divide the closed figure into two parts (the yellow part and the purple part in the third area diagram). The area calculation processing is performed by enclosing the corresponding pixel sampling points. Specifically, in the yellow part, 7 triangle structures are constructed by connecting P03, P04, P05, P06, P07 and P08 with P01. Since all sampling points have corresponding coordinates, the area of ​​the yellow part can be quickly calculated. Similarly, the area of ​​the purple part can also be quickly calculated. If the area ratio of the purple part (small area part) to the yellow part (large area part) is greater than the preset value, the preset value can be 40%. The typical case corresponds to Figure 12 As shown in M3, the current Longjing tea is marked as "No".

[0080] S5 If the area ratio of the small area to the large area is less than or equal to the preset value, find the vertex of the longest side in the small area, connect the vertex with the origin, and as described by the L2 line segment in the three-area diagram, if the angle A between the connecting line and the Y axis (or the L1 in the yellow part) is greater than the set value, the preset value can be 45 degrees, and the typical case also corresponds to Figure 12 As shown in M3, the current Longjing tea is marked as "No".

[0081] In order to prevent the typical situation Figure 12 As shown in M4, that is, the leaf area is small, the angle is small, but the leaf is thin and long, in S5, if the ratio of the length of the diagonal line L2 of the small area part to the length of the longest diagonal line L1 is greater than the preset value, the preset value can be such as 0.75, then the current Longjing tea is marked as "No".

[0082] S6, under the control of the control host, marks the current Longjing tea as "yes". So far, this method has visually identified the special-grade Longjing tea that meets the requirements through image contour analysis.

[0083] In order to improve efficiency, in any step of steps S2 to S5, if the current Longjing tea has been marked as "no", the process returns to step S1 and the Longjing tea at the next position on the selection conveyor belt 40 is set as the current Longjing tea.

[0084] When the current Longjing tea is identified as "yes", the current position deviation value is calculated. The distance deviation value can be the distance from the current position to the standard position of the air nozzle 45 based on the position distance of the mark 48, and the time value of the distance value is calculated based on the running speed value of the selection conveyor belt 40. When the time value is reached, under the control of the control host, the air nozzle 45 is operated to spray in a point-like manner through the control valve, so that the current Longjing tea marked as "yes" is driven to the first collection box 44, and the other Longjing tea marked as "no" is transported to the second collection box 46.

[0085] At this point, this solution is based on the Longjing tea grading standards and uses image contour analysis to achieve the selection operation of special-grade Longjing tea. On the other hand, through differentiated parameter requirements, corresponding selection operations can also be implemented for first-grade or other grades of Longjing tea, and it is efficient and accurate.

[0086] In summary, the present invention provides a stacking device, wherein the loading mechanism can realize the loading of multiple categories of pre-selected Longjing tea, and according to the corresponding characteristics of these Longjing teas, differentiated loading operations are carried out on time in a reasonable and orderly manner and with a set mixing ratio. At the same time, the present invention has multiple loading mechanisms, which can perform a variety of combined loading and stacking operations according to the set requirements, and finally can flexibly and efficiently implement the stacking operation of Longjing tea;

[0087] In order to make the stacking operation more uniform, this solution adopts the method of secondary vibration conveying, and uses the transverse conveyor belt to flatten and stack the primary selected Longjing tea delivered by all the feeding mechanisms and perform vibration mixing operations, so the back-end product has excellent consistency;

[0088] This solution uses electrostatic adsorption to remove foreign matter such as dust, powder, lint, or fine particles from the pre-selected Longjing tea. This can improve the purity of the Longjing tea, reduce the impact of such foreign matter on subsequent selection operations, and improve the stability of equipment operation.

[0089] The selection operation of this solution is mainly carried out by the image contour analysis method of visual recognition. Since Longjing tea is a flat tea, it is always placed on the conveyor belt with both sides facing forward and backward. Therefore, this method can fully utilize the characteristics of the flat tea and greatly improve the recognition efficiency and accuracy. It can also reduce the system calculation amount and improve the overall recognition efficiency.

[0090] As the visual recognition method of this scheme, Longjing tea is photographed vertically downward by a camera. Due to the fixed height, the length of the current Longjing tea can be quickly deduced through the number of pixels corresponding to the current Longjing tea in the image. Therefore, according to the Longjing tea grade standard, the current Longjing tea can be quickly predicted, thereby greatly improving efficiency; this scheme will also adopt sub-pixel edge detection operations, and through pixel sampling, the outline of the current Longjing tea will be polygonized, thereby realizing a variety of subsequent recognition and comparison operations; in this scheme, through feature analysis of special-grade Longjing tea, including technical features such as length, top shape, enclosed area ratio, angle and branch length, special-grade Longjing tea can be accurately distinguished and identified, which can solve the problem of traditional manual participation and reduce damage to Longjing tea during the selection operation.

Claims

1. A Longjing tea selection method based on image profile analysis, using a stacking device, the stacking device comprising: The loading mechanism is used to load various types of pre-selected Longjing tea into the corresponding materials; A mixing mechanism, for uniformly mixing and spreading the pre-selected Longjing tea from the plurality of feeding mechanisms; The impurity removal mechanism is used to remove impurities from the pre-selected Longjing tea after being processed by the mixing mechanism; A selection mechanism, which performs fine sorting operations on the pre-selected Longjing tea by visual photography; The feeding mechanism includes a plurality of feeding hoppers, a feeding conveyor belt is arranged below the feeding hopper, and a vibrating conveying mechanism is arranged at the front end of the conductive feeding mechanism, and the front end of the vibrating conveying mechanism has a 45-degree bevel lead-out outlet; the mixing mechanism includes a transverse conveyor belt, which is arranged below the bevel lead-out outlet of the vibrating conveyor mechanism, and the width of the transverse conveyor belt matches the size of the bevel lead-out outlet; the impurity removal mechanism is arranged at the rear end of the transverse conveyor belt, which includes a plurality of electrostatic adsorption components and an impurity removal conveyor belt, and the impurity removal conveyor belt is arranged below the electrostatic adsorption component; the selection mechanism includes a plurality of selection conveyor belts, the front end of the selection conveyor belt is used to receive the pre-selected Longjing tea from the rear end of the impurity removal conveyor belt, a camera is arranged at a fixed position just above the selection conveyor belt, the camera is used to shoot the Longjing tea just below it, the camera is connected to a control host, an air nozzle is provided at a fixed position on one side of the selection conveyor belt behind the camera, a first collection box is provided on the opposite side of the air nozzle, the air nozzle is connected to an air source and a valve, the valve is connected to the control host, and a second collection box is provided at the end of the selection conveyor belt; It is characterized in that it includes the following steps: S1 uses the camera to shoot the Longjing tea at the current position on the selected conveyor belt, obtains the current image and sends it to the control host; S2 performs pixel positioning on the Longjing tea image in the current photo, calculates the number of pixels corresponding to the longest diagonal according to the number of pixels in the X-axis direction and the Y-axis direction, and determines the length of the current Longjing tea according to the pixel number value and a preset relationship between pixels and length. If the length value is not within the set length interval, the current Longjing tea is marked as "no"; S3: If the length of the current Longjing tea is within the set length range, perform sub-pixel edge detection on the current photo, construct and sample pixel points at specific intervals, connect adjacent pixel sampling points, and construct a closed graph consisting of pixel sampling points and connecting lines. The longest diagonal of the graph space is used as the Y axis, and the rear end of the Y axis is used as the coordinate origin. All pixel sampling points are placed in the coordinate system, and several adjacent pixel sampling points on the left and right are connected at the vertex of the Y axis to fit a triangle structure. If the vertex angle of the triangle structure is greater than a preset value, mark the current Longjing tea as "no". S4: If the vertex angle of the triangle structure is less than or equal to a preset value, perform acute angle search processing on at least three adjacent pixel sampling points, determine the current acute angle point, connect the acute angle point with the coordinate origin, divide the closed figure into two parts, and calculate the area of ​​the enclosed interval of the corresponding pixel sampling points. If the area ratio of the small area part to the large area part is greater than the preset value, mark the current Longjing tea as "no". S5: If the area ratio of the small area portion to the large area portion is less than or equal to a preset value, find the endpoint of the longest side in the outline of the small area portion as a vertex, connect the vertex with the origin, and if the angle between the connecting line and the Y axis is greater than the set value, mark the current Longjing tea as "no"; S6 marks the current Longjing tea as "yes", calculates the distance deviation between the current position of the Longjing tea and the jetting position of the air nozzle, and calculates the time required for the Longjing tea to move the distance based on the running speed value of the selection conveyor belt. When the time value is reached, the air nozzle is operated to jet by controlling the valve, and the current Longjing tea marked as "yes" is driven to the first collection box.

2. The method for selecting Longjing tea based on image profile analysis according to claim 1, wherein: The feeding conveyor belt is made of flexible material, and its conveying surface is provided with a plurality of grooves. A uniform mechanism is provided in the middle of the feeding conveyor belt.

3. The method for selecting Longjing tea based on image profile analysis according to claim 2, wherein: The uniformity mechanism is used to spread the pre-selected Longjing tea evenly onto the conveying surface of the loading conveyor belt. The uniformity mechanism includes a horizontal cross bar and a plurality of staggered rollers arranged on the horizontal cross bar. A motor is arranged at one end of the horizontal cross bar, and a flexible scraper is arranged at the end of the cross bar.

4. The method for selecting Longjing tea based on image profile analysis according to claim 1, wherein: The vibrating conveying mechanism includes a vibrating plate and a vibrating mechanism arranged below the vibrating plate. The vibrating plate is connected to the frame through multiple elastic parts. The rear end of the vibrating plate matches the output port of the feeding conveyor belt, and the front end of the vibrating plate is a 45-degree bevel output port.

5. The method for selecting Longjing tea based on image profile analysis according to claim 1, wherein: The electrostatic adsorption component includes an electrostatic adsorption roller and an electrostatic adsorption roller motor that spans the top of the impurity removal conveyor belt. The electrostatic adsorption roller is connected to a high-voltage electrostatic generator, and the surface of the electrostatic adsorption roller is uniformly provided with static electricity. Sliders are arranged at both ends of the electrostatic adsorption roller, and the sliders are equipped with vertical slide grooves. The sliders are connected to a servo cylinder, and the servo cylinder is used to drive the slider and the electrostatic adsorption roller to rise and fall along the slide groove, and to adjust the distance between the electrostatic adsorption roller and the upper surface of the impurity removal conveyor belt.

6. The method for selecting Longjing tea based on image profile analysis according to claim 5, characterized in that: A foreign matter collection mechanism is arranged behind the electrostatic adsorption roller in the direction of rotation. The foreign matter collection mechanism includes a scraper adhered to the surface of the electrostatic adsorption roller, and a U-shaped groove located on one side below the scraper and fixedly connected to the slider. A screw conveyor is arranged in the U-shaped groove, and the screw conveyor is used to continuously discharge impurities accumulated in the U-shaped groove along its axial direction.

7. The method for selecting Longjing tea based on image profile analysis according to claim 5, characterized in that: A plurality of funnel-shaped material collecting structures are arranged at the rear end of the impurity removal conveyor belt, and an inclined guide plate is arranged in front of the funnel-shaped material collecting structure. The lower end of the guide plate is arranged above the front end of the selection conveyor belt. The running speed of the selection conveyor belt is greater than the running speed of the impurity removal conveyor belt. The selection conveyor belt is a conveyor belt structure with a light-colored bottom plate.

8. The method for selecting Longjing tea based on image profile analysis according to claim 1, wherein: In step S5, if the ratio of the length of the diagonal line of the small area portion to the length of the longest diagonal line is greater than a preset value, the current Longjing tea is marked as "no".

9. The method for selecting Longjing tea based on image profile analysis according to claim 1, wherein: In any one of steps S2 to S5, if the current Longjing tea has been marked as "no", the process returns to step S1, and the next Longjing tea to be identified on the selection conveyor belt is used as the current Longjing tea.

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