Reasonable Use of Invisible Light Illumination to Improve Visual Inspection Efficiency

Machine vision has traditionally been defined as a system that uses machines instead of human eyes to make various measurements and judgments, and has been very maturely applied to various fields of industry and national production. In machine vision applications, lighting is one of the very key technologies. By adjusting the information such as the shape, illumination angle, and brightness of the light source, it can significantly highlight the features we want to detect or measure, and shield out unwanted information. Interference to the system.

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In the past, machine vision technology relied on many light sources to capture images, including fluorescent lamps, quartz halogen lamps, LEDs, metal halides (mercury), and xenon. In the current vision system, more, more common and mature, are Various types of visible light LED light sources. However, what we are going to discuss today are two invisible light lighting technologies that are being used in machine vision systems and solving many practical problems, namely ultraviolet and infrared lighting, in addition to visible light LEDs. Reasonable use of invisible light in the visual system can greatly improve system efficiency. This article mainly introduces the application of infrared imaging.

Infrared is an electromagnetic wave between microwave and visible light. Its wavelength is usually from 760nm to 1mm. It is a kind of non-visible light with a longer wavelength than red light. Infrared light covers the band of thermal radiation emitted by objects at room temperature. The following uses two typical application cases to briefly introduce the application of infrared imaging technology in machine vision.

The first typical application is iris recognition. The iris is a ring-shaped film located between the black pupil and the white sclera on the surface of the human eye. It shows rich visual characteristics, such as spots, stripes, filaments, crowns, crypts, etc. under infrared light. Iris recognition has uniqueness, stability, non-invasiveness, and security. It is a commonly used recognition method in artificial intelligence pattern recognition. With the aid of infrared light, not only can the image of the iris be acquired quickly and accurately, but because the human eye cannot perceive infrared light, it will not affect the human eye. The image below shows an iris image taken under infrared conditions. Using this image, you can accurately identify a person's identity.

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The second typical application is EL detection in the photovoltaic industry. It adopts the electroluminescence characteristics of solar cell modules, and cooperates with Veszvision's own industrial digital cameras with high-efficiency response to the infrared band, which can detect the hidden cracks, broken grids, black hearts, black edges, low-efficiency sheets, and sintered mesh of solar cell modules. There are many kinds of defects such as grain, fragments, over-engraved edges, material defects, etc. The effect is shown in the following figure:

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Of course, in addition to the two typical applications mentioned above, infrared thermal imaging and near-infrared imaging technologies are also very common in other industries, including but not limited to scientific research, detection, medical treatment, communications, monitoring, and military. If you encounter a problem that cannot be solved by visible light, please call us to discuss.