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提出了一种用于探测热钢表面质量的光学方法。该方法基于四个激光源,这四个激光源从不同的方向以掠入射方式对钢坯表面进行照射。一台垂直固定于表面上方的CCD线列摄象机俘获由各个光源单独产生的散射光。表面缺陷会造成与各个光源方向及入射角相关的阴影和亮视场图形。为了能根据正常反射率和表面几何变化来鉴别实际表面缺陷,就需要这样的多光源结构。先将各光源分别产生的图形转换成数字,然后用一种简单而快速的算法将它们组合起来。我们在实验室用该方法对冷钢坯样品进行了试验。获得了诸如气泡、铁鳞嵌入、大裂纹和针眼之类大多数表面缺陷的性能特征。对于工业样机,我们计划将扫描速率定为每秒几千条线,这将通过为每个激光源选择不同的波长和通过使用一个四波长CCD线列摄象机来实现。
An optical method for detecting the surface quality of hot steel was proposed. The method is based on four laser sources that irradiate the surface of the billet by grazing incidence from different directions. A CCD line camera mounted vertically above the surface captures the scattered light produced by each light source alone. Surface defects cause shadow and bright field patterns associated with the direction and angle of incidence of each light source. In order to be able to identify actual surface defects based on normal reflectivity and surface geometry changes, such a multi-light source structure is needed. Convert the graphics generated by each light source into numbers first and then combine them in a simple and fast algorithm. Cold billet samples were tested by this method in the laboratory. The performance characteristics of most surface defects such as bubbles, scale-in embedding, macro-cracks and pinholes are obtained. For industrial prototypes, we plan to set the scan rate to a few thousand lines per second, by choosing a different wavelength for each laser source and by using a four-wavelength CCD line camera.