Flange nut is a kind of mechanical part widely used in the industrial field, especially in some fine production and processing fields, it is often necessary to use professional precision nuts for production and assembly of products. In recent years, with the continuous improvement of automation requirements in the industrial production field, machine vision detection technology, as a new technical means, has been widely used in the fields of industry, medical treatment, telemetry detection and intelligent transportation. Many flange nut manufacturers are still using the traditional manual sampling method to control the quality of their products, which not only relies heavily on human resources and improves the cost of the enterprise, but also leads to a large number of missed inspection due to the separation of the detection process and the production process.

The detection and screening system of flange nut based on machine vision detection technology is very important for changing this situation. Although with the increasing persification of industrial application requirements, the current shape of mechanical parts is more and more complex, but most of these complex shapes are composed of lines and arcs. Therefore, the feature recognition and detection of lines and circles is still the basis and important content of these complex shape detection.