What is the principle of visual inspection machine's appearance defect detection?

Machine vision equipment is an important part of automation industry. In industrial production automation, with machine vision measurement, detection of various size parameters of the workpiece, such as length measurement, circle measurement, Angle measurement, arc measurement, area measurement, not only can obtain the size parameters of online products, but also can make online real-time decision and sorting of product appearance, defect detection and removal, the application is very common.

Principle of machine vision appearance defect detection:

The optical characteristics of various defects on the surface of the product must be different from those of the product itself. When the light incident on the surface of the product, all kinds of defects and defects will be different from the surrounding areas in terms of reflection and refraction. For example, when uniform light is incident vertically on the surface of the product, if there is no defect on the surface of the product, the direction of the outgoing light will not change, and the detected light is uniform. When the surface of the product contains a defect, the light emitted will change and the image detected will change accordingly.

Due to the existence of defects, stress concentration and deformation occur around it, which is also easy to observe in the image. In case of light transmission defects (such as cracks, bubbles, etc.), light will be refracted at the defect position, and the intensity of light will be greater than that of the surrounding area, so the light detected on the camera target will be enhanced accordingly. If a light-absorbing impurity (such as sand) is encountered, the light at the defect site becomes weaker, and the light detected on the camera's target surface is weaker than the surrounding light. The corresponding defect information can be obtained by analyzing the intensity change and image characteristics of the image signal collected by the camera.

The detection equipment of machine vision system can replace the traditional manual detection, realize the online high-speed automatic detection of product appearance, realize the automatic identification of product surface defects and defect characteristics, with the advantages of high efficiency, high precision, low cost, simple operation, coupled with powerful visual software, easy to adjust, flexible and convenient, and the measurement data can be stored. Easy to establish statistical analysis, easy to quickly find problems, to solve problems, is the industry testing technology of choice.