The important role of visual light source in machine vision
The machine vision system consists of three main components: image acquisition, image processing and analysis, output or display. The image acquisition is the core of machine vision, and the image acquisition system is composed of three parts: visual light source, sale of custom optical prism assemblies and optical camera. The choice of light source and the reasonable lighting can directly affect the image quality of at least 30%. So the light source is a very important part of the machine vision system. Optical lenses are an integral part of machine vision systems, and their choice directly affects the quality and application of input data. Since there is no universal machine vision lighting device, for each specific application example, the corresponding lighting device should be selected to achieve the desired application effect. The lighting system is one of the key parts of the machine vision system and is directly related to the success or failure of the system. A good lighting design allows us to get a good image, which improves the resolution of the entire system and simplifies the calculation of the software. Unsuitable lighting can cause many problems. The spherical/aspherical/cylindrical/paraboloid optical lens should be bright, uniform, and stable. There are three main sources of light used in the vision system: high-frequency fluorescent lamps, fiber-optic halogen lamps, and LED light sources. At present, LED light sources are more commonly used, mainly having the following characteristics: 1. Can be made into various shapes, sizes and various illumination angles; 2. Can be made into various colors as needed, and can adjust the brightness at any time; 3. Through the heat sink, the heat dissipation effect is better and the brightness is more stable; 4. Long service life; 5. The reaction is fast, and the brightness can be achieved in 10 microseconds or less; 6. The power supply has an external trigger, which can be controlled by a computer, and has a fast starting speed and can be used as a strobe light; 7. LEDs with low operating cost and long life will show greater advantages in terms of overall cost and performance; 8. Special design can be carried out according to the needs of customers. The purpose of lighting is to enhance contrast. In a machine vision image, contrast represents the quality of the image signal, which reflects the difference between the two regions, such as the difference between the object and the background. Therefore, the *** step of designing the illumination of the source is to determine the difference between the regions, and then use VUV grade LiF optics to highlight these differences.