Continuous innovation in machine vision technology drives industrial automation
Nowadays, with the advent of Industry 4.0, machine vision technology has gradually played an important role in industrial automation. The continuous innovation of machine vision technology has promoted the advancement of industrial automation, intelligent security and artificial intelligence industries. The development of the field in which this technology can be applied also brings more development potential and opportunities.
Everyone says that 80% of human perception of external information is obtained through the eyes, and the amount of information contained in the image is the greatest. Then the emergence of machine vision technology is to equip the machine equipment with the perception of the outside world, so that the machine has the same visual function as human beings, thus achieving various functions of detection, judgment, recognition and measurement.
Today, let's take a look at the charm of machine vision technology.
Five typical architectures of machine vision
I remember that when I was attending a conference on machine vision technology, a technical singer specifically emphasized the importance of lighting in machine vision. It is understood that lighting is an important factor affecting the input of the machine vision system, which directly affects the quality and application effect of the input data.
The light source can be divided into visible light and invisible light. Several commonly used sources of visible light are white, fluorescent, mercury, and sodium. The shortcoming of visible light is that light energy can not be kept stable. How to make light energy stable to a certain extent is an urgent problem to be solved in practice. On the other hand, ambient light may affect the quality of the image, so a protective screen can be used to reduce the effects of ambient light.
The lighting system can be divided into: backlight, forward illumination, structured light and stroboscopic illumination according to its illumination method. Among them, the back illumination is placed between the light source and the camera, and has the advantage of obtaining a high contrast image. The forward illumination is that the light source and the camera are located on the same side of the object to be tested, which is convenient for installation. The structured light illumination projects a grating or a line source or the like onto the object to be measured, and demodulates the three-dimensional information of the object to be measured according to the distortion generated by them. The stroboscopic illumination is to illuminate a high-frequency light pulse onto an object, and the camera capture requires synchronization with the light source.
The lens is equivalent to the existence of the human eyeball. It is mainly responsible for beam modulation and signal transmission in the machine vision system. It is understood that most of the lenses on the market so far can meet the needs of machine vision applications, but more professional machine vision systems may require custom lenses and coatings. Fortunately, many lens manufacturers with in-house production capabilities are ready to customize lenses to meet these application needs. Of course, these custom lenses can be expensive, so they are typically only used in specific imaging systems that are not cost sensitive (such as military applications) or in high volume consumer products.
3. Industrial camera
The most essential function of industrial cameras in machine vision systems is the conversion of optical signals into electrical signals. Compared with ordinary cameras, it has higher transmission force, anti-interference ability and stable imaging capability. According to different standards, there are many classifications: according to the output signal method, it can be divided into analog industrial cameras and digital industrial cameras; according to different chip types, it can be divided into CCD industrial cameras and CMOS industrial cameras.
4. Image capture card
Although the frame grabber is only a component of a complete machine vision system, it plays a very important role, directly determining the interface of the camera: black and white, color, analog, digital, and so on. More typical are PCI capture card, 1394 capture card, VGA capture card and GigE Gigabit network capture card. Some of these capture cards have built-in multiplexers that can be connected to multiple cameras while capturing multiple channels of information.
5. Machine vision software
Machine vision software is a key component of automated processing in machine vision systems. The software package is redeveloped according to the specific application requirements, and image acquisition, display, storage and processing can be completed automatically. Through the pre-transmission to the dedicated image processing software, according to the pixel distribution and brightness, color and other information, into a digital signal; machine vision software then perform various operations on these signals to extract the characteristics of the target, and then control the scene according to the results of the discrimination Device action.
Five common application areas
Machine vision can be said to be the soul window of industrial automation systems. From object/barcode identification, product inspection, appearance size measurement to robotic arm/transmission equipment positioning, machine vision technology can play a stage, so its application range is very Wide range, the industry application field is even more dazzling.
1. Image recognition application
Image recognition is the use of machine vision to process, analyze, and understand images to identify targets and objects in various modes. Image recognition The most typical application in the field of machine vision industry is the recognition of two-dimensional codes. The two-dimensional code is the most common one of the commonly used bar codes. A large amount of data information is stored in this small two-dimensional code, and the product is tracked and managed through bar code. Through the machine vision system, the bar code of various material surfaces can be easily recognized and read, which greatly improves the efficiency of modern production. .
2. Image detection application
Detection is one of the most important applications in the machine vision industry. Almost all products need to be tested, and manual detection has many drawbacks. The accuracy of manual detection is low. If it is used for a long time, the accuracy is not guaranteed, and the detection is not guaranteed. Slow speeds can easily affect the efficiency of the entire production process. Therefore, machine vision is also very extensive in the application of image detection, such as the detection of coin edge characters. In the fifth set of RMB issued in October 2000, the side of the round coin enhanced the anti-counterfeiting function. In view of the strict control requirements of the production process, a visual inspection system was installed on the last process of coinage; Color positioning and color inspection, printing quality inspection of beverage bottle caps during packaging, bar code and character recognition on product packaging, and defect detection of glass bottles. Machine vision system for the detection of defects in glass bottles, also includes the scope of medicinal glass bottles, which means that machine vision is also involved in the field of medicine, its main tests include size inspection, bottle appearance defect detection, bottle shoulder defect detection, bottle Mouth detection, etc.
3. Visual positioning application
Visual positioning requires a machine vision system to quickly and accurately find the part being tested and confirm its position. In the field of semiconductor packaging, devices need to adjust the pickup head according to the chip position information obtained by machine vision, accurately pick up the chip and bind it. This is the most basic application of visual positioning in the machine vision industry.
4. Object measurement application
The biggest feature of machine vision industrial applications is its non-contact measurement technology, which also has high precision and high speed performance, but non-contact and wear-free, eliminating the potential for secondary damage caused by contact measurement. Common measurement applications include gears, connectors, automotive parts, IC component pins, twist drills, and Luoding thread inspection.
5. Object sorting application
In fact, the object sorting application is built after the identification and detection, and the image is processed by the machine vision system to realize sorting. It is often used in machine vision industrial applications for food sorting, automatic surface sorting of parts, cotton fiber sorting, etc.