A time-synchronized method for tobacco foreign object detection and rejection, and a rejection control method.

Abstract

This invention discloses a time-synchronized method and rejection control method for detecting and removing foreign objects in tobacco products. The method uses a line scan camera to acquire real-time images of the conveyed material at a fixed line frequency and frame rate. After image acquisition, the images are sent to an image processing unit for detection and processing. If foreign objects need to be rejected after image processing, the detection result data is sent to the timing and rejection control unit, which then drives the corresponding rejection solenoid valve to remove the foreign objects or unqualified materials from the material. This invention achieves time-synchronized control between image acquisition, image processing, and foreign object rejection, ensuring that each function of the system operates in an orderly manner according to a fixed rhythm. The entire detection and rejection system operates stably and without temporal chaos, improving the accuracy of rejecting target objects in the material. Furthermore, the rejection rate is improved through extended control of the rejection action.

Description

Technical Field

[0001] This invention relates to a time-synchronized method and rejection control method for detecting and removing tobacco foreign objects, specifically a time-synchronized method and rejection control method for acquiring, processing, and removing tobacco foreign objects using image detection and computer technology. Background Technology

[0002] Currently, automated control of production lines has been achieved in fields such as tobacco and food processing. The application of computer vision systems to monitor raw materials or products on the production line in real time, and to detect and remove foreign objects or substandard materials from the production line, has been widely adopted in recent years. In the tobacco industry, a common method involves installing a line-scanning camera on the upper surface of the material, perpendicular to the conveyor line, to acquire real-time images. After image acquisition, the images are processed and the results are sent to multiple solenoid valves neatly arranged on the upper surface of the material, perpendicular to the conveyor line, behind the line-scanning camera. If a foreign object is detected, the corresponding solenoid valve is activated for removal.

[0003] As production efficiency demands increase, so too do the requirements for the timeliness and accuracy of material inspection and rejection. A line scan camera is used to acquire real-time images of the conveyed materials at a fixed line frequency and frame rate. After image acquisition, the images are sent to an image processing unit for detection and processing. If foreign objects need to be rejected after image processing, the detection results are sent to a timing and rejection control unit, which then drives the corresponding rejection solenoid valve to remove foreign objects or unqualified materials. Because this process takes place on a running production line, the time for image acquisition, processing, and rejection is extremely short, requiring extremely high continuity and timeliness. Therefore, a method is needed to quickly and accurately synchronize the timing of image acquisition, processing, and rejection to ensure the orderly and stable operation of the entire inspection and rejection process. Summary of the Invention

[0004] The technical problem to be solved by this invention is to improve the timeliness and accuracy of detecting and removing impurities and unqualified materials in tobacco processing, to ensure that each execution action in the process of image acquisition, image processing and impurity removal is carried out in an orderly manner, to achieve accurate removal of impurities, and to make the entire system work stably.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A time-synchronized method and rejection control for foreign object detection and rejection in tobacco products. The method uses a line scan camera to acquire real-time images of the conveyed material at a fixed line frequency and frame rate. After image acquisition, the images are sent to an image processing unit for image detection and processing. If foreign objects need to be rejected after image processing, the detection result data is sent to the timing and rejection control unit, which then drives the corresponding rejection solenoid valve to remove the foreign objects or unqualified materials from the material.

[0007] Specifically, the time-synchronized method for detecting and removing tobacco foreign objects includes:

[0008] The conveyor belt for transporting materials operates at a constant speed. The line scan camera is set to continuously acquire images at a fixed line frequency and frame rate. The number of lines and frame rate for each frame are fixed, thus ensuring that the acquisition time for each frame is constant.

[0009] The time interval between each image frame is t. The action cycle of the three functions of image acquisition, processing, and rejection is based on the image frame signal of the line scan camera.

[0010] After receiving the frame signal of one frame, the image acquisition unit begins acquiring images. After time t, the acquisition of one frame is complete. After acquiring one frame, the image acquisition unit receives the frame signal of two frames and continues acquiring those two frames. Simultaneously, after receiving the frame signal of two frames, the image processing unit synchronously begins processing the acquired one frame. The processing result for the one frame must be completed within time t. After another time t, the image acquisition unit receives the frame signal of three frames and begins acquiring those three frames. Simultaneously, the image processing unit receives the frame signal of three frames and synchronously begins processing the two frames. At the same time, after receiving the frame signal of three frames, the rejection unit removes impurities based on the processing result of the one frame. If the rejection unit has not received the processing result of the one frame when it receives the frame signal of three frames (processing time of one frame > t), the rejection unit does not reject the one frame, and the processing unit immediately releases the resources occupied by the one frame to prepare for the processing of the two frames. The timing control method for subsequent image acquisition, processing, and removal is repeated in the same manner. This ensures a high degree of consistency in the action rhythm between image acquisition, processing, and removal, guaranteeing a stable and smooth workflow.

[0011] Specifically, the tobacco foreign object removal and control method includes:

[0012] (1) Generate the elimination control matrix

[0013] The number of columns in the matrix is ​​divided at equal intervals along the width of the conveying device according to the number of rejection units. The number of rows in the matrix is ​​divided at equal intervals along the height of the image in each frame, with the number of pixels acquired in the rejection control cycle as the step size. A matrix is ​​constructed using the number of rows and columns to control the position and time of the rejection unit's action.

[0014] After the image detection process is completed, the removal control matrix of the target object is obtained based on the shape, contour and other characteristics of the target object.

[0015] (2) The corresponding rejection information is sent to the rejection solenoid valve according to the rejection control matrix. The rejection solenoid valve at the corresponding position opens for the corresponding time according to the rejection control matrix and then accurately rejects the target object in the material.

[0016] Once a foreign object is identified in the image, the foreign object rejection solenoid valve A should be activated to remove the object at an appropriate time. Since different foreign objects have different movement trajectories, the opening time T of either the extended solenoid valve (its adjacent solenoid valves A-1 and A+1) or the extended solenoid valve A can be set in the solenoid valve arrangement direction to increase the likelihood of the foreign object being hit, thereby further increasing the rejection accuracy of the entire rejection system.

[0017] The beneficial effects of this invention include:

[0018] I. It realizes the timing synchronization control between image acquisition, image processing and debris removal, so that the various functions of the system are carried out in an orderly manner according to a fixed rhythm, and the working sequence of the entire detection and removal system is not chaotic and the operation is stable;

[0019] II. Improved the accuracy of removing target items from materials;

[0020] III. It achieves extended control of the rejection action, thereby improving the rejection rate. Attached Figure Description

[0021] Figure 1 This is a system composition diagram of the method of the present invention.

[0022] Figure 2 This is a schematic diagram of the timing synchronization method of the present invention.

[0023] Figure 3 This is a schematic diagram illustrating the elimination method of the solenoid valve extension in this invention.

[0024] Figure 4 This is a diagram illustrating time allocation. Detailed Implementation

[0025] The technical solutions of the present invention will now be described in detail with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the protection scope of the present invention.

[0026] Example 1

[0027] First, a 2048-pixel linear scan camera continuously acquires images of the material at a fixed scanning frequency and frame rate. After image acquisition, the images are sent to the image processing unit for processing. If any target object needs to be rejected after image processing, a rejection signal is sent to the rejection solenoid valve. After the rejection solenoid valve is activated, foreign objects or unqualified materials are rejected. Since the above process is carried out on the running production line, the time for image acquisition, processing, and rejection is extremely short. The requirements for the continuity and timeliness of the entire workflow are extremely high. A method that can quickly and accurately synchronize the sequence of image acquisition, processing, and rejection is needed to ensure the orderly and stable operation of the entire detection and rejection process.

[0028] like Figure 1 As shown, the system consists of: a conveyor belt, image data acquisition, image detection and processing, timing and rejection control, and rejection valve.

[0029] like Figure 2 As shown, the actions of image acquisition, processing, and object removal are synchronized, and the time allocation method in the timing synchronization method is as follows: Figure 4 The time allocation diagram shown illustrates the division of time.

[0030] First, set: line scan camera resolution (horizontal resolution) - Rh; number of rows in one frame image (vertical resolution) - Rv; conveyor belt speed v; conveyor belt width W; frame image acquisition time T1; frame image processing time T2; rejection control element action time (i.e., execution time to complete the rejection action) T3; result transmission time T5; rejection preparation time T6.

[0031] Then, complete the following steps based on the above conditions:

[0032] S1 calculates the detection accuracy based on the width of the conveying device and the horizontal resolution of the image:

[0033]

[0034] In the formula: R represents the detection accuracy, W represents the width of the conveyor belt, and Rh represents the lateral resolution of the acquired image.

[0035] S2 calculates the longitudinal field of view detection size based on the longitudinal resolution and detection accuracy of the line scan camera:

[0036] Fv=Rv*R

[0037] In the formula: Fv represents the longitudinal field of view detection size, Rv represents the longitudinal resolution of the image, and R represents the detection accuracy.

[0038] S3 calculates the scanning frequency of the line scan camera based on the conveyor belt speed and detection accuracy.

[0039]

[0040] In the formula: S represents the scanning frequency of the line scan camera, v represents the conveyor belt speed, and R represents the detection accuracy.

[0041] S4 calculates the scanning cycle of the line scan camera using the scanning frequency of the line scan camera:

[0042]

[0043] In the formula: T′ represents the scanning period of the line scan camera, and S represents the scanning frequency of the line scan camera.

[0044] S5 calculates the frame interval time of the line scan camera based on the scan cycle of the line scan camera:

[0045] t=T′

[0046] In the formula: t represents the frame signal interval time, and T′ represents the scanning period of the line scan camera.

[0047] S6 calculates the distance from the scan line of the line scan camera to the end of the conveyor belt using the frame signal interval time of the line scan camera and the conveyor belt speed:

[0048] L1 = t * 2 * v

[0049] In the formula: L1 represents the distance from the scan line of the line scan camera to the end of the conveyor belt, t represents the frame signal interval time, and v represents the conveyor belt speed.

[0050] S7 calculates the distance from the end of the conveyor to the rejection point by taking the action time of the rejection element and the conveying speed of the conveyor:

[0051] L2 = T3 * v

[0052] In the formula: L2 represents the distance from the end of the conveying device to the rejection point, T3 represents the action time of the rejection control element, and v represents the conveying speed of the conveying device.

[0053] Furthermore, the timing synchronization method in the technical solution is adopted for setting the time allocation of line scan camera image acquisition, image processing, and rejection. Material starts scanning and completes frame image acquisition in time T1, followed by frame image processing in time T2, and then rejection data transmission and rejection preparation. At this point, the material reaches the end of the conveyor belt, and the rejection solenoid valve completes the corresponding rejection action based on the frame signal and image processing results. T3 is the action time of the rejection control element. The time allocation method must satisfy: T1 = T2 = T4 + T5 + T6; T3 = rejection element action time; the image processing algorithm's running time should be less than T4.

[0054] After calculating the above series of parameters, the image detection and removal system designed based on these parameters can meet the synchronization time requirements of each execution action between image detection, image processing, and removal.

[0055] Furthermore, extension solenoid valves A-1 and A+1, which open the debris removal solenoid valve A, are arranged in the solenoid valve arrangement direction to compensate for the uncertainty caused by the different movement trajectories of different debris (such as...). Figure 3 (As shown).

[0056] Furthermore, by extending the action time T3 of the rejection control element of the debris rejection solenoid valve A, the probability of debris being hit is increased, in order to offset the uncertainty caused by the different movement trajectories of different debris.

[0057] Furthermore, according to the rejection control method in the technical solution, after the image is detected and identified, the rejection control matrix of the target object to be rejected can be obtained by using the conversion method from the target debris image to the rejection control matrix. Based on the rejection control matrix, the corresponding rejection information is sent to the rejection solenoid valve. The rejection solenoid valve at the corresponding position opens for the corresponding time according to the result of the timing calculation to accurately reject the target object in the material.

Claims

1. A method for controlling the removal of foreign objects from tobacco, characterized in that, include: (1) Generate the elimination control matrix The number of columns in the matrix is ​​divided at equal intervals along the width of the conveying device according to the number of rejection units. The number of rows in the matrix is ​​divided at equal intervals along the height of the image in each frame, with the number of pixels acquired in the rejection control cycle as the step size. A matrix is ​​constructed using the number of rows and columns to control the position and time of the rejection unit's action. After the image detection process is completed, the removal control matrix of the target object to be removed is obtained based on the shape and contour characteristics of the target object. (2) The corresponding rejection information is sent to the rejection solenoid valve according to the rejection control matrix. The rejection solenoid valve at the corresponding position opens for the corresponding time according to the result of the timing synchronization method and then accurately rejects the target object in the material. The timing synchronization method includes: Step (1): The conveyor belt for conveying materials has a constant speed. The line scan camera is set to continuously acquire images at a fixed line frequency and frame rate. The number of acquisition lines and the frame rate of each frame are fixed. The time interval between each frame is t. Step (2), the action rhythm of the three functions of image acquisition, processing and elimination is based on the image frame signal of the line scan camera; After receiving the frame signal of 1 frame image, the image acquisition unit begins to acquire images. After time t, the acquisition of 1 frame image is completed. After acquiring 1 frame image, the image acquisition unit will receive the frame signal of 2 frames image and continue to acquire 2 frames image. At the same time, after receiving the frame signal of 2 frames image, the image processing unit synchronously begins to process the acquired 1 frame image. The processing result of 1 frame image is completed within time t. After another time t, the image acquisition unit receives the frame signal of 3 frames image and begins to acquire 3 frames image. At the same time, after receiving the frame signal of 3 frames image, the image processing unit synchronously begins to process 2 frames image. At the same time, after receiving the frame signal of 3 frames image, the rejection unit removes impurities based on the processing result of 1 frame image. If the rejection unit has not received the processing result of 1 frame image when it receives the frame signal of 3 frames image, the rejection unit does not perform rejection processing on 1 frame image, and the processing unit synchronously releases the various resources occupied by the processing unit for 1 frame image to prepare for the processing of 2 frames image.

2. The tobacco foreign object removal and control method according to claim 1, characterized in that, The timing synchronization method further includes: S1, set the following parameters The horizontal resolution of the line scan camera is Rh, the number of rows in one frame is Rv, the conveyor belt speed is v, the conveyor belt width is W, the frame image acquisition time is T1, the frame image processing time is T2, the action time of the rejection control element is T3, the result transmission time is T5, and the rejection preparation time is T6. S2, calculate the detection accuracy respectively. Longitudinal field of view inspection dimensions Line scan camera scanning frequency Line scan camera scanning cycle Frame signal interval of line scan camera Distance from the scan line of the line scan camera to the end of the conveyor belt and the distance from the end of the conveyor to the rejection point : ； S3, the material starts from the scanning line and completes frame image acquisition in time T1, then completes frame image processing and rejection data transmission and rejection preparation in time T2. At this time, the material reaches the end of the conveyor belt, and the rejection solenoid valve completes the corresponding rejection action according to the frame signal and image processing results. T3 is the action time of the rejection control element. The time allocation method satisfies: T1=T2=T4+T5+T6, where T4 is defined as the maximum running time of the image processing algorithm.

3. The tobacco foreign matter removal and control method according to claim 1 or 2, characterized in that: Extended solenoid valves A-1 and A+1, which open the debris removal solenoid valve A, are arranged in the solenoid valve arrangement direction to offset the uncertainty caused by the different movement trajectories of different debris. The extended solenoid valves are adjacent to solenoid valves A-1 and A+1 of the debris removal solenoid valve A. Once debris is identified in the image, the debris removal solenoid valve A should be activated to remove the debris at an appropriate time.

4. The method for controlling the removal of foreign matter from tobacco according to claim 2, characterized in that: Extending the action time T3 of the rejection control element of the debris rejection solenoid valve A increases the likelihood of debris being hit, thus offsetting the uncertainty caused by the different movement trajectories of different debris.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the tobacco foreign object removal control method as described in any one of claims 1-4.

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