Market competition promotes the development of machine vision

In the modern industrial automation production, it involves a variety of inspection, measurement and part identification applications, such as automatic positioning of components of electronic assembly lines, printing quality inspection of beverage bottle caps, bar code and character recognition on product packaging, and the like. The common feature of this type of application is the continuous mass production and the very high demands on the appearance quality. Usually this kind of work with high repeatability and intelligence can only be completed by manual inspection. We often see hundreds of inspection workers behind the modernization line in some factories to perform this process, which is increasing the number of factories. At the same time, huge labor costs and management costs still cannot guarantee 100% inspection pass rate (ie "zero defect"). However, today's competition among enterprises obviously has not allowed 0.1% of defects to exist.

At this time, people began to consider the combination of the rapidity, reliability, and repeatability of results with the highly intelligent and abstract capabilities of human vision, resulting in the concept of machine vision. Machine vision is characterized by automation, objectivity, non-contact, and high precision. Compared with image processing systems in the general sense, machine vision emphasizes accuracy and speed, and reliability in industrial field environments. Machine vision is suitable for measurement, inspection and identification in mass production processes, such as: part assembly integrity, assembly dimensional accuracy, part machining accuracy, position and angle measurement, part identification, character recognition, etc. The largest application industry is : pharmaceuticals, manufacturing, food, beverages, medicine, etc., such as: rapid positioning of electronic components on high-speed placement machines; inspection of the number of pins; recognition of characters printed on the surface of the IC; capsule wall thickness and appearance in capsule production Inspection of defects; Inspection of the number and damage of balls in the production of bearings; Identification of production dates on food packaging; Inspection of placement of labels. At present, the application of the visual system in the world is in the ascendant. In 1998, the market size was 4.6 billion U.S. dollars. In China, the industrial vision system is still in the concept introduction period. Leading enterprises in various industries have started to solve the problem of production automation and have begun to Turn your attention to the automation of visual measurement.

The composition and classification of machine vision systems

Machine vision is the use of machines instead of the human eye to make measurements and judgments. The machine vision system converts captured targets into image signals through machine vision products (ie, image capture devices, sub-COMS, and CCD) and transmits them to a dedicated image processing system. Based on pixel distribution, brightness, color, and other information, it is converted into The digital signal; The image system performs various operations on these signals to extract the characteristics of the target, and then according to other results to control the equipment in the field.

Machine vision systems are characterized by increased flexibility and automation of production. In some dangerous working environments that are not suitable for manual work or artificial vision is difficult to meet the requirements, machine vision is often used instead of artificial vision. At the same time, in the process of large-scale industrial production, using artificial vision to check the product quality is inefficient and the precision is not high. Machine vision inspection methods can greatly improve the production efficiency and the degree of automation of production. In addition, machine vision is easy to implement information integration and is the basic technology for computer integration.

A typical industrial machine vision application system includes the following parts: light source, lens, CCD camera, image processing unit (or image capture card), image processing software, monitor, and communication (input and output unit). The workflow is as follows: Using the camera to obtain the image signal of the measured target, and then through the A / D conversion into a digital signal sent to a dedicated image processing system, according to pixel distribution, brightness and color, and other information, conduct a variety of operations to extract the characteristics of the target, and then The judgment result is output according to a preset criterion, and the control and actuation mechanism is controlled to perform corresponding processing. Machine vision is a comprehensive technology, including digital image processing technology, mechanical engineering technology, control technology, light source lighting technology, optical imaging technology, sensor technology, analog and digital video technology, computer hardware and software technology, human-machine interface technology. Machine vision emphasizes practicality, requires adaptability to the harsh environment of industrial sites, requires reasonable cost-effectiveness, common industrial interfaces, high fault tolerance and safety, and has strong versatility and portability. It emphasizes Real-time, requiring high speed and high precision.

In short, the application of machine vision systems can significantly reduce inspection costs, improve product quality, and accelerate production speed and efficiency. As a high-precision, non-contact measurement solution, the vision system involves optical and image processing algorithms. It is a highly specialized product in itself. In the entire measurement control system, position correction and feed control are often performed in conjunction with the motion control system. In addition, the visual system must have a distributed networking capability when the production line performs synchronous continuous inspection of multiple processes. The combination of advanced technologies such as machine vision and motion control, network communications is changing the face of industrial automation production.