Want to implement a series of basic human activities, such as living, working and learning must rely on their own organs, in addition to the brain, the most important thing is to our eyes, (industrial) robot is not exceptional also, to complete the normal production tasks, there is no a set of perfect, advanced visual system is hard to imagine.
The machine vision system USES machines instead of human eyes to make various measurements and judgments. It is an important branch of computing division, it combines optical, mechanical, electronic, computer software and hardware technology, involves the computer, image processing, pattern recognition, artificial intelligence, signal processing, optic-mechanical integration, and other fields. The rapid development of image processing and pattern recognition technology has also greatly promoted the development of machine vision.
Application of machine vision system
On the production line, such measurements and judgments made by people will cause errors and errors due to fatigue, personal differences, etc., but the machine will carry on tirelessly and steadily. Generally speaking, machine vision system includes lighting system, lens, camera system and image processing system. For each application, we all need to consider the system and running speed of image processing speed, the size of the color or black and white camera, were used to detect target or detecting target with and without defects, view how much, need more high resolution and contrast how much, etc. From the perspective of function, a typical machine vision system can be divided into: image acquisition, image processing and motion control.
The working process of the
The main working process of a complete machine vision system is as follows:
1. The workpiece positioning detector detects that the object has moved to the visual field center near the camera system, and sends the trigger pulse to the image acquisition part.
2. According to the preset procedure and time delay, the image acquisition part respectively sends starting pulses to the camera and the lighting system.
3. The camera stops the current scan and starts a new frame scan, or the camera is in a waiting state before the start pulse arrives, and starts a frame scan after the start pulse arrives.
4. Open the exposure mechanism before the camera starts a new frame scanning, and the exposure time can be set in advance.
5. When another starting pulse turns on the light, the light opening time should match the exposure time of the camera.
6. After the camera is exposed, the scanning and output of one frame of images are officially started.
7. the image acquisition section receives the analog video signal and digitizes it through A/D, or directly receives the digital video data after the camera digitizes it.
8. the image acquisition section will store the digital image in the memory of the processor or computer.
9. The processor processes, analyzes and recognizes the image to obtain the measurement result or the logical control value. < br>10. Process the results to control the operation of the assembly line, carry out positioning, and correct the error of movement, etc.
Advantages
The advantages of the machine vision system include:
1. Non-contact measurement will not cause any damage to the observer or the observer, thus improving the reliability of the system.
2. It has a wide spectral response range, such as the use of invisible infrared measurement, which expands the visual range of human eyes.
3. Working steadily for a long time, it is difficult for human to observe the same object for a long time, while machine vision can perform measurement, analysis and recognition tasks for a long time.
4. The application of machine vision system is more and more extensive. In industry, agriculture, national defense, transportation, medical, financial, and even sports, entertainment industry has obtained widespread application, it has deep into every aspect of our life, production and work.
Intelligent robots in science fiction movies
———As shown in the picture below, it is a processing machine device controlled by computer.
———The device mainly carries out image acquisition and processing positioning of the processed object through the front-end camera, so as to complete the processing.
———Mechanical parts of the precision by the proficiency of the workers and work experience as well as the machining tools, such as various types of machine tools) to today's digital and intelligent processing equipment (such as numerical control machine), more can meet the need of society and the development of high precision, difficult parts are processed.
The visual system can be simply summarized by three independent and interrelated modules: object image acquisition, image processing and instruction sending.
The design of visual system is divided into software design and hardware design.
Hardware design of visual system
The hardware of the visual system consists of lens, camera, image acquisition card, input and output unit and control device.
The quality of a visual system depends on the level of camera pixels, the quality of hardware, and more importantly, the coordination and reasonable use of each component.
——In the bad natural environment, in the production of a line, in many complex situations, in order to guarantee the normal work of the entire visual system, a system of various hardware must have good wear resistance and withstand all kinds of unpredictable situation and test.
——With the progress of science and technology and the need of modern production and living, is a machine vision system, especially the rapid development of intelligent mechanical, hardware of the original system has not adapt to the new need, therefore, must improve the level and quality of the hardware to ensure normal operation of the system.
——Camera, video camera, image acquisition card, the control unit, input/output device structure is like a computer monitor, power supply, the host (processor, memory, hard disk, video card, etc.), each of the components is crucial, if their quality closes nevertheless, the whole machine can't work properly, let alone to complete complex tasks and give the task.
Software design of visual system
——The software design of visual system is very important. Under the current trend of information technology, intelligent control increasingly depends on the function of software.
——Visual system software design is a complex subject, not only should consider programming optimization, but also the validity of the algorithm is given, and its realization, in the process of software design to consider the possible problems.
——The software design of visual system needs to detect and improve its robustness to adapt to the complex external environment (robustness is the robustness of the system). It is the key to system survival in exceptional and dangerous situations.
A visual navigation software process flow chart
Practical application of visual system
•The urban traffic warning system of machine vision technology
•In recent years, with the development of economy, China's major cities within the traffic infrastructure construction has been rapid development, however, although city built more and more wide roads, flyovers, to build more and more traffic signal is more and more complex, the incidence of road congestion and traffic accident has not been apparent ease, transportation industry, especially in urban traffic under increasing pressure.
At present, with the modernization and intellectualization of urban transportation, the research on relevant fields in China has become a new hotspot. Intelligent Transportation System; Referred to as ITS) study was in Europe, America, Japan, Canada and so on wide attention of many developed countries, they have invested heavily used in intelligent transportation system research, and a large number of simulation experiments, many subsystems have been able to preliminary achieve desirable intelligent degree. More and more facts have proved that the advanced ITS effective use of the existing traffic facilities, reduce the number of traffic load and environmental pollution, ensure traffic safety, improve transport efficiency, and promote social and economic development, improve people's quality of life, and can promote the social informatization and the formation of new industries. City traffic warning system based on machine vision technology, it is a subsystem of advanced traffic management system, is through according to the change of traffic situation of early warning, cooperate with the traffic management of intelligent monitoring system.
The framework of urban traffic warning system based on machine vision technology
• introduction to main functional modules of the system
• visual monitoring: urban traffic environment changes in real time. Video monitoring technology is used to collect relevant data and send the detected environmental feature value to the information fusion processor.
• information fusion processor: the output results are obtained through the fuzzy neural network method.
• monitoring and early warning: according to and make decisions, i.e. adjust real-time traffic information and signal control accordingly, and take emergency rescue measures for areas that will or have an accident.
Robot vision
• a system that enables robots to have visual perception function.
, robot vision can get environment of a two-dimensional image through visual sensor, and carries on the analysis and interpretation through visual processor, and then converted into symbols, and let the robot can identify objects, and determine its position.
• robot vision is broadly called machine vision, and its basic principle is similar to computer vision.
• a system that enables robots to have visual perception function.
, robot vision can get environment of a two-dimensional image through visual sensor, and carries on the analysis and interpretation through visual processor, and then converted into symbols, and let the robot can identify objects, and determine its position.
• robot vision is broadly called machine vision, and its basic principle is similar to computer vision.
• computer vision studies the general theory of visual perception, and studies the calculation methods of hierarchical information representation of visual processes and functional modules of visual processing. Machine vision, on the other hand, focuses on the special vision system with application as the background and only provides the description of the scene related to the execution of a specific task.
The robot vision hardware mainly includes image acquisition and visual processing, while image acquisition consists of lighting system, visual sensor, analog-digital converter and frame memory. According to different functions, robot vision can be divided into visual inspection and visual guidance, which is widely used in electronics, automobile, machinery and other industrial sectors as well as medical and military fields.
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