Yong-Ju Jeon

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Presently, product inspection for quality control is becoming an important part in the steel manufacturing industry. In this paper, we propose a vision-based method for detection of pinholes in the surface of scarfed slabs. The pinhole is a very tiny defect that is 1-5 mm in diameter. Because the brightness in the surface of a scarfed slab is not uniform(More)
Presently, automatic inspection algorithms are widely used to ensure high-quality products and achieve high productivity in the steelmaking industry. In this paper, we propose a vision-based method for detecting corner cracks on the surface of steel billets. Because of the presence of scales composed of oxidized substances, the billet surfaces are not(More)
In this paper, we present a new detection algorithm for line defects of scale-covered steel billets. Because of the presence of scales on the billet surface, features of surface images such as brightness and textures are non-uniform. To minimize the influence of scales and to improve the accuracy of detection, a new detection method based on undecimated(More)
We propose a new defect detection algorithm for scale-covered steel wire rods. The algorithm incorporates an adaptive wavelet filter that is designed on the basis of lattice parameterization of orthogonal wavelet bases. This approach offers the opportunity to design orthogonal wavelet filters via optimization methods. To improve the performance and the(More)
This paper presents an automated inspection algorithm for a thick plate. Thick plates typically have various types of surface defects, such as scabs, scratches, and roller marks. These defects have individual characteristics including brightness and shape. Therefore, it is not simple to detect all the defects. In order to solve these problems and to detect(More)
Presently, product inspection based on vision systems is an important part of the steel-manufacturing industry. In this work, we focus on the detection of seam cracks in the edge region of steel plates. Seam cracks are generated in the vertical direction, and their width range is 0.2-0.6 mm. Moreover, the gray values of seam cracks are only 20-30 gray(More)
In this paper a novel filtering scheme combined with a lighting method is proposed for defect detection in steel surfaces. A steel surface has non-uniform brightness and various shaped defects, which cause difficulties in defect detection. To solve this problem we propose a sub-optimal filtering that is combined with a switching-lighting method. First,(More)
Non-destructive automatic inspection systems are in high demand in the steel industry, for controlling the quality and increasing the productivity of steel products. In this study, we developed an algorithm for detecting scratch defects on slabs by using image-processing techniques. To reduce the effect of lighting condition and amplify the features of the(More)
The recently proposed normalized least mean squares algorithm reuses estimated past coefficient vectors for the finite impulse response model and effectively reduces the misadjustment. The affine projection algorithm, which is an extension of the normalized least mean squares algorithm, generally suffers from relatively high misadjustment in the steady(More)
In this paper, we introduce an image-processing algorithm that detects pinholes in steel slabs. Because the pin-hole is relatively small and similar to noise components, it is difficult to distinguish pinhole from a steel slab surface. To increase detection accuracy, we propose a new algorithm for pinhole detection. We applied Gabor filters to extract(More)
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