Application of most popular machine vision and sci

  • Detail

The application of machine vision and scientific imaging in the manufacture of mechanical and electrical products in recent years, the continuous progress of computer technology has made image acquisition a widely used source of measurement data, thus promoting the new breakthrough of computer automatic machine vision and scientific imaging technology in the detection technology of electronic products, Therefore, there is a new mechanism that "any detection process completed by human is suitable to replace" with machine vision technology This is because compared with machines, people are emotional and tired, so it is unreliable to use people as machines. Therefore, the emergence of this new mechanism is inevitable

machine vision system

machine vision system generally includes light source, lens, CCD camera, image processing unit (or image acquisition card), image processing software, monitor, communication/I/O unit, etc. The composition of machine vision system is shown in Fig. 1 (a), and the actual example is shown in Fig. 1 (b)

Figure 1 (a) the basic group of machine vision system also provides strong support for Chalco Shandong enterprises to improve the research and utilization capacity of high-end materials. Figure 1 (b) enumeration of the use composition of machine vision system - schematic diagram of the basic composition of PC based vision system

light source: like the lighting factors of visual sensors, it is an important factor affecting the input of machine vision system, It directly affects the quality of input data and application effect. For each specific application instance, the corresponding lighting device shall be selected to achieve the best effect. Its light source can be divided into visible light and invisible light. Several common visible light sources are white flag lamp, fluorescent lamp, mercury lamp and sodium lamp. On the other hand, the ambient light may affect the image quality, so the PC based scheme can be adopted mainly for the electronic production test equipment. Its advantages are high performance, high flexibility and high cost performance. It is very suitable for the difficult, high-resolution and high-speed machine vision applications

therefore, protective screen can be added to reduce the impact of ambient light. The lighting system can be divided into back lighting, forward lighting, structured light and frequency flash lighting according to its illumination method. Among them, back illumination is to place the measured object between the light source and the camera, and its advantage is that it can obtain high contrast images. Forward illumination means that the light source and camera are located on the same side of the tested object, which is convenient for installation. Structured light illumination projects grating or linear light source onto the measured object, and demodulates the three-dimensional information of the measured object according to their distortion. Frequency flash lighting is to irradiate high-frequency light pulses onto objects. Camera shooting requires synchronization with light source

lens: lens selection should pay attention to focal length, target height, image height, magnification, distance from image to target, center point/node and distortion

camera: it can be divided into standard resolution digital camera and analog camera according to different standards. Different cameras and high-resolution cameras should be selected according to different practical applications: line scan CCD and area array CCD; Monochrome camera and color camera

it also provides technical support for the development of low halogen, low smoke and environment-friendly flame retardant PP image acquisition card: the image acquisition card is only a part of a complete machine vision system, but it plays a very important role. The image acquisition card directly determines the interface of the camera: black and white, color, analog, digital, etc. Typically, PCI or AGP compatible capture cards can quickly transfer images to computer memory for processing. Some acquisition cards have built-in multiplexers. For example, you can connect eight cameras that do not operate together for several times, and then tell the acquisition card which camera captures the information. Some acquisition cards have built-in digital input to trigger the acquisition card to capture. When the acquisition card captures images, the digital output port will trigger the gate

visual processor: visual processor integrates acquisition card and processor. In the past, when the computer speed was slow, the visual processor was used to speed up the visual processing task. Now, because the acquisition card can quickly transfer images to the memory, and the computer is much faster, now the visual processor is less used

working process: the output of the vision system is not the image and video signal, but the detection result (such as dimension data) after operation and processing. Generally, machine vision testing is to use a machine instead of the naked eye to measure and judge Firstly, CCD camera is used to convert the captured object into image signal, which is transmitted to the special image processing system. According to the pixel distribution, brightness, color and other information, it is converted into digital signal. The image system performs various operations on these signals to extract the features of the target, such as area, length, quantity, position, etc. Finally, output the results according to the preset tolerance and other conditions, such as size, angle, offset, number, qualified/unqualified, yes/no, etc. After the upper computer (such as PC and PLC) obtains the detection results in real time, it commands the motion system or i/o system to perform corresponding control actions (such as positioning and classification)

machine vision is an emerging automation market. The reason for this is that the main machine vision technology actually uses cameras instead of human eyes, and image processing software instead of brain to inspect or identify the quality of products on the production line. It is basically composed of light source, lens, camera, image acquisition card, image processor/software and necessary i/o. Machine vision inspection has very high efficiency, repeatability and accuracy, and in many cases it can not be replaced by human eyes. The vision system can automatically complete tasks such as component measurement and inspection quickly, accurately and with high repeatability, which can help manufacturers improve product quality and productivity. The vision system can generate valuable monitoring data at every step of the manufacturing process, which can also help control engineers expand the function of process diagnosis.

the application of computer automatic machine vision can be roughly divided into four categories: positioning, measurement, recognition and defect detection. The overview of deformation measurement of testing machine is that positioning is the most widely used. The machine vision system can be used to inspect the electronic components on the motherboard, and can also be used to control the manipulator. CCD is installed on the manipulator, and the positioning of image recognition is used to drive the manipulator to do virus research, drug mixing, etc Some high-risk medical research. In addition to accuracy, it is also relatively safe for human life

it can be seen that the speed and accuracy of machine vision inspection have become a new way to inspect machine electronic products, which depends on the characteristic advantages of the following two types of systems. One is the system components and application software for image acquisition, and the other is the standard machine vision system for the production workshop. (end)

Copyright © 2011 JIN SHI