Visual sensing technology is one of the seven major categories of sensing technology. Visual sensors refer to sensors that calculate the characteristic quantities (area, center of gravity, length, position, etc.) of an object through image processing of images captured by a camera, and output data and judgment results. Visual sensors are the direct source of information for the entire machine vision system, mainly composed of one or two graphic sensors, sometimes accompanied by light projectors and other auxiliary equipment. The main function of a vision sensor is to obtain sufficient original images to be processed by a machine vision system.
Working principle of visual sensing：
Vision originates from a way of obtaining external environmental information in the biological world, and is the most effective means for natural organisms to obtain information. It is one of the core components of biological intelligence. "80% of human information is obtained through vision. Based on this inspiration, researchers began to install" eyes "for machinery to enable machines to obtain external information through" looking "like humans, resulting in the birth of a new discipline - computer vision. Through research on biological visual systems, people imitate and create machine vision systems, although there is a significant difference from human visual systems.", But this is a breakthrough in sensor technology. The essence of visual sensor technology is image processing technology, which captures signals from the surface of an object and draws images for presentation to researchers.
Visual sensors have thousands of pixels that capture light from an entire image. The clarity and fineness of an image is usually measured in terms of resolution, expressed in terms of the number of pixels. After capturing the image, the visual sensor compares it with the reference image stored in memory for analysis. For example, if a visual sensor is set to identify machine components with eight bolts correctly inserted, the sensor knows that components with only seven bolts should be rejected, or components with misaligned bolts. In addition, regardless of where the machine component is located in the field of view, and regardless of whether the component rotates within a 360 degree range, visual sensors can make judgments. The emergence of visual sensing technology solves the problem of other sensors being unable to operate due to site size limitations or large detection equipment, which is widely welcomed by the industrial manufacturing industry.
Visual sensing technology includes 3D visual sensing technology, and 3D visual sensors have a wide range of applications, such as multimedia mobile phones, network cameras, digital cameras, robot visual navigation, automotive safety systems, biomedical pixel analysis, human-computer interfaces, virtual reality, monitoring, industrial testing, wireless remote sensing, microscopy technology, astronomical observation, autonomous ocean navigation, scientific instruments, and so on. These different applications are based on 3D visual image sensor technology. In particular, 3D imaging technology has urgent applications in industrial control and autonomous vehicle navigation.
Intelligent visual sensing technology is also a kind of visual sensing technology. Intelligent visual sensors under intelligent visual sensing technology, also known as intelligent cameras, are the fastest developing new technology in the field of machine vision in recent years. Intelligent camera is a small machine vision system with functions of image acquisition, image processing, and information transmission. It is an embedded computer vision system. It integrates image sensors, digital processors, communication modules, and other peripherals into a single camera. Due to this integrated design, the complexity of the system can be reduced and reliability improved. At the same time, the system size has been greatly reduced, broadening the application field of visual technology.
The advantages of intelligent visual sensors such as ease of learning, use, maintenance, and installation, as well as the ability to construct reliable and effective visual inspection systems in a short period of time, have led to the rapid development of this technology. The image acquisition unit of the visual sensor is mainly composed of a CCD/CMOS camera, an optical system, a lighting system, and an image acquisition card. It converts the optical image into a digital image and transmits it to the image processing unit.