CN103406286A - Online grading method for external quality of fruit based on LabVIEW - Google Patents

Abstract

The invention discloses an online grading method for the external quality of a fruit based on LabVIEW. The online grading method is characterized in that a LabVIEW mounted computer, a PLC (Programmable Logic Controller), an image acquiring device, a conveying device and a grading device are provided in the method. The online upgrading method comprises the following steps of firstly, controlling the image acquiring device to shoot a fruit image to be tested in real time through LabVIEW, and then, calling an IMAQ (Image Acquisition) toolbox to analyze the size, shape, defect point and color of each fruit image to obtain a grading result; and conveying fruits to ports of chutes with corresponding grades through the conveying device, sending a control character for controlling the grading device to the PLC by the LabVIEW to enable a pneumatic executive component to act to push the fruits into the chutes with the corresponding grades to finish the grading operation. The external quality of the fruit is graded by using the method; and compared with the traditional grading method, the online grading method has the advantages of low cost, high speed and precision, interface friendliness, convenience in use and maintenance and the like.

Description

An Online Grading Method of Fruit External Quality Based on LabVIEW

technical field

The invention relates to a method for grading fruit external quality, in particular to a method for grading fruit external quality based on LabVIEW.

Background technique

China's fruit industry has developed rapidly after 30 years of reform and opening up, and has become the world's largest producer of fruit, with a total fruit output reaching 100 million tons. From the analysis of the entire industrial chain of fruit products in the country, the current problems affecting quality and price efficiency mainly occur in the process of transforming products into commodities. The concept of fruit quality control is relatively lagging behind, which is the shortest "short board" currently affecting the improvement of the efficiency of the Chinese fruit industry system. It can be seen that using advanced equipment and technology to detect fruit quality, grade fruit, and control fruit quality has become an urgent task for the development of agricultural automation.

At present, fruit quality inspection mostly adopts manual inspection and mechanical grading. Manual inspection is not only time-consuming and inefficient, but also has a great relationship with the inspector's own technical level and experience, which has become a bottleneck factor restricting processing efficiency. The traditional mechanical grading technology is only grading according to the size and weight of the fruit, and the fruit is divided into a limited number of grades by using the holes or gaps on the conveyor belt or conveyor rollers. This type of grading method is usually simple in structure, but the fruit may be damaged due to collision during grading, and it is generally only used for those fruits that are not sensitive to mechanical load and will be further processed subsequently.

Therefore, combining computer technology and electrical control technology, it is of great significance to develop a fruit quality grading method with low cost, high speed and high efficiency.

Contents of the invention

The object of the present invention is to provide a method for grading fruit external quality based on LabVIEW, which can realize online grading of fruit external quality.

The method comprises a computer equipped with LabVIEW, a PLC, an image acquisition device, a transmission device and a grading device. The invention utilizes the powerful instrument connection and data communication capabilities of LabVIEW to establish a fruit external quality grading platform in a computer to complete fruit image real-time acquisition, quality analysis and grading. First, the image acquisition device is controlled by LabVIEW to capture the image of the fruit to be tested in real time; then IMAQ is called to analyze the size, shape, defect point and color of the fruit image to obtain the classification result; Send control characters to the PLC to control the grading device, so that the pneumatic actuator will act, and the fruit will be pushed into the trough of the corresponding grade, thus completing the grading.

The image acquisition device is composed of a photoelectric sensor, a light box, and a camera. The photoelectric sensor monitors the position of the fruit in real time. Once the fruit reaches the optimal position for shooting, a program is called to take a photo of the fruit to complete the acquisition of the fruit image.

The conveying device is composed of a 1500mm×67mm×2mm conveyor belt, a three-phase AC geared motor, AC380V, an output speed of 130r/min, rolling bearings, and rollers to complete the fruit conveying.

The classifying device is composed of a photoelectric sensor, a solenoid valve, a material pushing cylinder and a material trough. When the fruit reaches the trough of the corresponding grade, the photoelectric sensor outputs a high level, and LabVIEW sends a command character to the PLC through the VISA interface to control the corresponding solenoid valve, so that the pushing cylinder performs a grading action, pushes the material into the trough, and completes the process. Grading of fruit.

The fruit external quality grading man-machine interface of the present invention also includes a man-machine interface, which has the function of checking the original image of the fruit; it has the function of checking the status of size analysis, shape analysis, defect point analysis and color analysis; It has the function of modifying grading threshold parameters and grading results.

The external quality of fruit mainly refers to size, shape, defects and color. The present invention can also be easily extended to the detection and classification of other external qualities. The system provided by the invention combines computer technology and electrical control technology, and has low cost, high speed and high efficiency, and has important significance.

Description of drawings

Fig. 1 is a schematic diagram of the system structure of the present invention;

1. Light box 2. CCD camera 3. Feed photoelectric sensor 4. Belt conveyor line 5. Computer equipped with LabVIEW 6. Communication module 7. PLC 8. Three-phase AC gear motor 9. Grading mechanism

Fig. 2 is a schematic diagram of system operation of the present invention;

Fig. 3 is a software flowchart of the present invention;

Figure 4 is the front panel of size processing;

Fig. 5 is the program block diagram of size processing;

Figure 6 is the front panel of the shape analysis;

Fig. 7 is the program block diagram of shape analysis;

Figure 8 is the front panel of defect point analysis;

Fig. 9 is a program block diagram of defect point analysis;

Figure 10 is the front panel of the color analysis;

Figure 11 is a program block diagram of color analysis.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

The system structure schematic diagram of the present invention described in Fig. 1, this system comprises the computer that LabVIEW is equipped with, PLC, image acquisition device, transmission device and classifying device. The invention utilizes the powerful instrument connection and data communication capabilities of LabVIEW to establish a fruit external quality grading platform in a computer to complete fruit image real-time acquisition, quality analysis and grading. First, the image acquisition device is controlled by LabVIEW to capture the image of the fruit to be tested in real time; then IMAQ is called to analyze the size, shape, defect point and color of the fruit image to obtain the classification result; Send control characters to the PLC to control the grading device, so that the pneumatic actuator will act, and the fruit will be pushed into the trough of the corresponding grade, thus completing the grading.

The image acquisition device is composed of a light box 1, a CCD camera 2 and a photoelectric sensor 3, and a computer 5 equipped with LabVIEW transfers the fruit image for quality analysis and classification judgment. The conveying device is composed of a 1500mm×67mm×2mm belt conveying line 4, a three-phase AC geared motor 8 (AC380V, output speed 130r/min), rolling bearings, and rollers to complete the fruit conveying. Described grading mechanism 9 is made up of photoelectric sensor, solenoid valve, pushing material cylinder, hopper is formed, and the computer 5 that LabVIEW is equipped with will grade result send order character to PLC7 by the VISA interface of communication module 6, realizes fruit's classification by grading mechanism 9. Grading.

The system operating schematic diagram of the present invention described in Fig. 2, the photoelectric sensor monitors the position of fruit in real time, once the fruit arrives at the best position for shooting, the CCD camera takes a photo to complete the acquisition of the fruit image. LabVIEW calls IMAQ to analyze the size, shape, defect point and color of the fruit image to obtain the classification result. The conveying device transports the fruit to the corresponding level of material slot, the photoelectric sensor outputs a high level, and LabVIEW sends command characters to the PLC through the VISA interface to control the corresponding solenoid valve, so that the pneumatic actuator moves and pushes the fruit into the corresponding level of material. In the tank, the external quality grading of the fruit is completed.

Shown in Fig. 3 is the software flowchart of the present invention, and working process is as follows:

(1) Communication detection, check whether the communication between the PLC and the upper computer is correct.

(2) The fruit feeding photoelectric sensor constantly detects whether there is fruit passing by. If there is no fruit passing by, the feed photoelectric sensor continues to detect, once there is fruit passing by, it will go to the next step.

(3) PLC corresponding input coil becomes high level. LabVIEW reads the state of the PLC input coil, and at the same time calls the camera camera program to capture fruit images.

(4) LabVIEW analyzes fruit size, shape, defect point and color through IMAQ.

Size Analysis: Use the IMAQ threshold function to process images in the block diagram. Take the threshold value from the image, only extract the pixels within the threshold value in the image, and ignore the pixels outside the threshold value, so as to segment the image. Then use the IMAQ FILLHOLE function to fill the gaps in the particles of the image, and finally use Particle Analysis to analyze the particle points in the image. According to the set adjacent categories, the node analyzes the particle points, and obtains the number, area, number, quality and direction of particles (see Figure 4-5 for details).

Shape analysis: IMAQ Extract contour extracts a single, best contour from a color image. If the image itself has a scale, the processed contour also has a scale. IMAQ FIT CONTOUR calculates an approximate equation based on the image contour to describe the contour. If the contour is scaled, the equations will be corrected for the exact position. IMAQCONTOUR DISTANCE compares the template contour and target contour and calculates the distance between them. IMAQ OVERLAYCONTOUR Overlays contour lines on the image. Finally, a custom subvi is used to analyze the edge angle of the contour, etc., and analyze the shape according to the set value (Figure 6-Figure 7).

Defect point analysis: analyze the number and area of defect points. In this program, the threshold of the image is firstly performed, and the image is divided according to the required threshold value, and then the image is filled and unfilled respectively, and then the defect point is processed. Analyze, obtain the area with defect points and the area without defect points, and subtract them to obtain the area of defect points. Then calculate the proportion of defective points (Figure 8-Figure 9).

Color analysis: using a sequence structure, in the first sequence structure, the GET COLOR PROFIL function is mainly used to analyze the color of the apple surface in RGB, so as to obtain its RGB value. The call chain is used in the program, which returns the chain of each caller from the current VI to the top-level VI. Element 0 of the call chain array contains the name of the lowest level VI in the call chain. Subsequent elements are the callers of the lowest-level VI in the call chain. The last element of the call chain array is the name of the top-level VI. If the current VI is used as a subVI, you can use this function to find all VIs that call this subVI. Use IMAQ read to read the information of the image, and use get line color profile to process the obtained information to obtain the color information of the outline processed by the upper vi. The color of the apple can be obtained by taking the average of the RGB values of the color (Figure 10-Figure 11).

(5) Select which external quality is used for grading, extract the corresponding characteristic parameters, and calculate the grading result, transfer it to the Case Structure, and send command characters to the PLC through the VISA interface.

(6) Determine the grade corresponding to the fruit, and the pneumatic actuator acts to push the fruit into the trough of the corresponding grade, thereby realizing the grading of the fruit.

Claims (5)

1. a kind of online grading method of fruit external quality based on LabVIEW, it is characterized in that comprising installing the computer of LabVIEW, PLC, image acquisition device, transmission device and grading device; Call IMAQ to analyze the size, shape, defect point and color of the fruit image to obtain the grading result; the conveying device transports the fruit to the corresponding grade trough, and LabVIEW sends control characters to the PLC to control the grading device, so that the pneumatic actuator operates , push the fruit into the trough of the corresponding level. 2. The fruit external quality grading method according to claim 1, wherein the image acquisition device is composed of a photoelectric sensor, a light box, and a camera, and the photoelectric sensor monitors the position of the fruit in real time. position, call the program to take pictures of the fruit, and complete the acquisition of the fruit image. 3. The fruit external quality grading method according to claim 1, characterized in that the transmission device is composed of a 1500mm×67mm×2mm conveyor belt, a three-phase AC geared motor, AC380V, an output speed of 130r/min, rolling bearings, and rollers. Delivery of fruit. 4. The fruit external quality grading method according to claim 1, characterized in that the grading device is composed of a photoelectric sensor, a solenoid valve, a material pushing cylinder, and a material trough. When the fruit reaches the trough of the corresponding grade, the photoelectric sensor outputs a high level, and LabVIEW sends a command character to the PLC through the VISA interface to control the corresponding solenoid valve, so that the pushing cylinder performs a grading action, pushes the material into the trough, and completes the process. Grading of fruit. 5. The fruit external quality grading method according to claim 1, characterized in that: it also includes a man-machine interface, which has the function of checking the original image of the taken fruit; it has the ability to check the size analysis, shape analysis, defect point analysis and color The function of analyzing the status; it has the function of modifying the classification threshold parameters and the classification results.

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