Humans rely on their own organs to perform a series of basic activities, such as living, working, and learning. Apart from the brain, the most important organ is our eyes. Industrial robots are no exception. It is hard to imagine completing normal production tasks without a complete and advanced vision system.
Machine vision systems utilize machines to perform various measurements and judgments, replacing human eyes. It is an important branch of computer science, integrating technologies from optics, mechanics, electronics, and computer hardware and software, involving multiple fields such as computer science, image processing, pattern recognition, artificial intelligence, signal processing, and opto-mechatronics. The rapid development of technologies such as image processing and pattern recognition has also greatly promoted the development of machine vision.
Understanding Robot Vision Systems
Generally, a machine vision system includes a lighting system, a lens, a camera system, and an image processing system. For each application, we need to consider the system's operating speed and image processing speed, whether to use a color or monochrome camera, whether to detect the size of the target or whether to detect defects, the required field of view, the required resolution, and the required contrast ratio, etc.
Functionally, a typical machine vision system can be divided into three parts: image acquisition, image processing, and motion control.
1. Non-contact measurement does not cause any damage to either the observer or the observed, thereby improving the reliability of the system.
2. It has a wide spectral response range, for example, by using infrared measurements that are invisible to the human eye, thus expanding the visual range of the human eye.
3. Long-term stable operation: Humans find it difficult to observe the same object for a long time, while machine vision can perform measurement, analysis, and recognition tasks for extended periods.
4. The application fields of machine vision systems are becoming increasingly widespread. They have been widely used in industries such as manufacturing, agriculture, defense, transportation, healthcare, finance, and even sports and entertainment, and can be said to have penetrated into all aspects of our lives, production, and work.
I. Composition of Machine Vision System
The design of a vision system is divided into two main parts: software design and hardware design.
(I) Hardware Design of the Vision System
The hardware of a vision system mainly consists of a lens, camera, image acquisition card, input/output unit, and control device.
The quality of a vision system depends on the camera's pixel count, the quality of the hardware, and, more importantly, the coordination and proper use of its various components.
(II) Software Design of the Vision System
The software design of a vision system is a complex subject. It requires consideration of not only the optimization of the program design, but also the effectiveness of the algorithm and its feasibility. Potential problems must also be taken into account during the software design process.
After the software design of the vision system is completed, its robustness must be tested and improved to adapt to complex external environments.
II. Machine Vision Working principle
Robot vision hardware mainly consists of two parts: image acquisition and vision processing. Image acquisition comprises a lighting system, vision sensors, an analog -to-digital converter, and a frame buffer. Robot vision acquires two-dimensional images of the environment through vision sensors, analyzes and interprets them through a vision processor, and then converts them into symbols, enabling the robot to recognize objects and determine their locations.
The specific process is as follows:
III. Application Areas of Machine Vision
The challenge of industrial machine vision lies in precision and speed, both requiring millimeter-level accuracy, especially since the movements of industrial robot grippers occur in three-dimensional space. Depending on their function, robot vision can be divided into visual inspection and visual guidance.
What are the main application areas of machine vision ?
1) Touchscreen
With the development of technology, people have increasingly higher requirements for the interactive experience of electronic products. Touch screens, as the next generation of electronic product input devices, are gradually becoming the new favorite of devices such as tablets, mobile phones, e-readers, GPS devices, and game consoles. The manufacturing process of touch screens is complex. From upstream ITO glass coating, photolithography, and IC component processing, to midstream touch screen module bonding, screen printing, and cutting, and then to downstream touch screen module bonding and cover glass inspection, all of these processes place higher demands on the technology, making machine vision technology an essential technology for production and quality inspection in related stages.
2) FPD
The FPD (Flat Panel Display) industry encompasses various display devices such as LCD, LED, and OLED, with each technology and process being highly complex. LCD is currently the dominant display technology. The FPD industry demands extremely high production efficiency and product quality, making machine vision technology, as a non-contact, high-precision, and high-speed production method, an indispensable technological tool for inspection capabilities. From front-end ITO glass inspection and backlight module inspection to cell bonding, COG equipment for LCD modules, alignment bonding, cutting machines, and flying probe inspection equipment, the application of machine vision technology enhances the core competitiveness of equipment manufacturers.
3) Laser processing
Laser processing is a widely used industrial processing technology that utilizes the motion control of lasers to achieve high-precision marking, cutting, engraving, welding, and other functions. With the upgrading of laser processing techniques, traditional technologies can no longer meet the high-precision and high-speed requirements of industrial processing. This has led to the integration of machine vision technology and laser technology. Simultaneously, vision-based positioning and guidance enable high-precision processing, reducing the need for expensive precision fixtures, improving equipment accuracy, and lowering processing costs.
4) Solar energy
Solar energy, as one of the most valuable future green energy sources, is a key industry for national development. Short-term relative overcapacity places higher demands on solar cell production equipment. From the purity of silicon ingots and wafers to quality control during processing and coating, everything affects the final photovoltaic conversion efficiency of the solar cells. High-quality production lines can reduce scrap rates, thereby lowering the energy consumption-to-output ratio of solar cells and making solar energy a truly clean energy source. In the solar cell production process, technologies such as machine vision positioning, measurement, and inspection can significantly improve the yield and reduce production costs.
5) Semiconductors
Semiconductor technology is the foundation of the modern information industry and the earliest origin of machine vision technology. In the 1990s , European and American semiconductor companies applied image technology to the semiconductor industry, which gradually developed into today's machine vision technology and has become an indispensable key technology in the semiconductor industry. At the same time, the semiconductor industry is massive, and the Moore's Law effect constantly challenges industry processes, leading to increasingly higher requirements for machine vision in its production equipment.
6) PCB
Printed Circuit Boards (PCBs) are the primary carriers of electronic information products. In today's relatively mature PCB industry, fierce competition demands increasingly higher levels of comprehensive manufacturing capabilities from high-performance equipment. The development of PCB manufacturing technologies such as multilayer boards, flexible boards, and rigid-flex boards has placed even greater emphasis on PCB production processes. Machine vision technology is widely used in PCB manufacturing. In equipment such as film AOI, PCB AOI, PCB AVI, inner layer AXI, PCB screen printing, automatic exposure machines, SPI, and drilling machines, machine vision technologies for positioning and inspection enable rapid and accurate quality inspection and process control, improving product quality and production efficiency, and providing a reliable guarantee for equipment performance enhancement.
7) SMT
Surface Mount Technology (SMT) is another key sector in the electronics and information industry after PCB manufacturing, and it's also the birthplace of machine vision equipment manufacturers in China. The miniaturization of electronic components, the high density of component placement, and the complexity and diversity of component pin arrays all place higher demands on modern SMT equipment. By utilizing machine vision for positioning, measurement, and inspection, SMT equipment production efficiency, placement accuracy, and the stability of continuous placement operations can be improved. This contributes to equipment upgrades and technological advancements within the SMT industry.
8) Robotics and Factory Automation
Industrial robots are multi-jointed manipulators or multi-degree-of-freedom robots designed for industrial applications. They replace manual labor in performing monotonous, frequent, and long-term tasks, or in hazardous and harsh environments, such as stamping, pressure forging, heat treatment, welding, painting, plastic product molding, machining, and simple assembly. They are an important indicator of the automation level of modern factories. Combining robots with vision technology enables more precise assembly, welding, processing, and material handling.
9) Pharmaceutical manufacturing
The production and processing of pharmaceuticals are highly regulated processes, and even minor errors can have serious consequences. Using machine vision to achieve quality control and management of the pharmaceutical production process can improve drug and packaging quality, thereby safeguarding patient safety.
10) Logistics
Modern industrial production process management embodies the efficiency and sophistication of modern production. Through the identification and tracking of barcodes and characters, a one-to-one correspondence can be established between raw materials, components, finished products, packaging boxes, and product stacks, making modern production manageable and traceable. This has significant applications in industrial product production management and component traceability, in preventing cross-selling and ensuring safety in the food and beverage industry, and in component traceability in the automotive industry.
11) Automobile
As a highly automated, high-tech industry, the automotive sector has successfully implemented numerous advanced automation technologies across its various production processes. Many stages of automobile manufacturing have achieved unmanned operation, necessitating reliable inspection technology to verify the correctness of each assembly and the qualification of assembled components. Machine vision technology, with its unique technological advantages, has become the preferred choice for automated inspection systems. Machine vision is widely used in various stages of automobile manufacturing, such as the dimensional and appearance quality inspection of automotive parts and the verification of the correctness of automated assembly. Previously, traditional inspection methods were labor-intensive and easily affected by worker subjectivity and skill levels, failing to guarantee a high pass rate. Many automobile manufacturers have begun to experiment with machine vision inspection to replace traditional methods, achieving excellent results.
12) OCR
Optical Character Recognition (OCR) is widely used in many industries, such as printing, packaging, and logistics, involving processes like printing quality inspection, packaging quality inspection, and barcode inspection and character recognition on product packaging. These applications share common characteristics: continuous high-volume production, high requirements for appearance quality, and high repeatability and intelligence. By leveraging the accuracy, speed, and reliability of machine vision in industrial environments, character and barcode recognition enables automated and efficient measurement, inspection, and identification during the production process.
Traditional manufacturing is facing new disruptions, and transformation and upgrading will bring huge market opportunities to China's automation industry. Machine vision, as a highly intelligent product in the automation field, has enormous development potential in the future.
Chinese electronics manufacturers and contract manufacturers have been purchasing large amounts of automated equipment to replace manual labor in recent years to cope with China's growing labor shortage, and this trend is expected to peak in the next few years. This automation shift will occur within the next 2-3 years, undoubtedly creating new growth opportunities for machine vision products in the industry.
