Real-time automated visual inspection system for contaminant removal from wool

In the textile industry, scoured wool contains different types of foreign materials (contaminants) that need to be separated out before it goes into further processing, so that the textile machines are protected from damage and the quality of the final woollen products is ensured. This paper presents an automated visual inspection (AVI) system for detecting and sorting contaminants from wool in real time. The techniques were first developed in the lab and subsequently applied to a large-scale factory system. The combinative use of image processing algorithms in RGB and HSV colour spaces can segment 96% of contaminant types (minimum size around 4cm long and 5mm in diameter) in real-time on the lab test rig. One of the most important aspects of the system is to use the non-linear colour space transformation and merge the threshold algorithm in HSV colour space into the image processing algorithms in RGB colour space to enhance the contaminant identification in real time. The real-time capability of the system is also analysed in detail. The experimental results demonstrate that the factory AVI system could identify and remove the contaminants at a camera speed of around 800 lines/s and the conveyor speed of 20m/min in real time.

[1]  N. Otsu.  A threshold selection method from gray level histograms , 1979 .

[2]  P. W. Chudleigh,et al.  Detecting Colored Fiber Contaminants in Wool Top Using Balanced Illumination , 1985 .

[3]  Marvin R Paulsen,et al.  Real-Time Detection of Colour and Surface Defects of Maize Kernels Using Machine Vision , 1994 .

[4]  Roland T. Chin,et al.  Automated visual inspection: 1981 to 1987 , 1988, Computer Vision Graphics and Image Processing.

[5]  P. W. Chudleigh.  Detecting Colored Contaminants in Wool Using an Integrating Sphere , 1991 .

[6]  Edward Roy Davies,et al.  The use of variance and entropic thresholding methods for image segmentation , 1995, Pattern Recognit..

[7]  P.K Sahoo,et al.  A survey of thresholding techniques , 1988, Comput. Vis. Graph. Image Process..

[8]  Stan Sclaroff,et al.  Estimation and prediction of evolving color distributions for skin segmentation under varying illumination , 2000, Proceedings IEEE Conference on Computer Vision and Pattern Recognition. CVPR 2000 (Cat. No.PR00662).

[9]  Sankar K. Pal,et al.  A review on image segmentation techniques , 1993, Pattern Recognit..

[10]  John D. Holt,et al.  Real-time Industrial Visual Inspection: A Review , 1995, Real Time Imaging.

[11]  K. Plataniotis,et al.  Color Image Processing and Applications , 2000 .

[12]  M. Levesley,et al.  Development of a mechatronic sorting system for removing contaminants from wool , 2005, IEEE/ASME Transactions on Mechatronics.

[13]  Na Li,et al.  Real-time video object segmentation using HSV space , 2002, Proceedings. International Conference on Image Processing.

[14]  Andrew K. C. Wong,et al.  A gray-level threshold selection method based on maximum entropy principle , 1989, IEEE Trans. Syst. Man Cybern..

[15]  Charles A. Harlow,et al.  Automated Visual Inspection: A Survey , 1982, IEEE Transactions on Pattern Analysis and Machine Intelligence.

[16]  Du-Ming Tsai,et al.  A fast histogram-clustering approach for multi-level thresholding , 1992, Pattern Recognit. Lett..

[17]  Zhenwei Su,et al.  Identification of white contaminants and their removal from wool fibers , 2003, IS&T/SPIE Electronic Imaging.

[18]  T. G. King,et al.  An incremental real-time pattern tracking algorithm for line-scan camera application , 1994 .

[19]  Josef Kittler,et al.  Minimum error thresholding , 1986, Pattern Recognit..

[20]  Sanguklee,et al.  A comparative performance study of several global thresholding techniques for segmentation , 1990 .

[21]  G. M. Abbott.  An Automated Color-Sorting Device for Wool and Other Fibers , 1995 .

[22]  Tim King.  Vision-in-the-loop for control in manufacturing , 2003 .

[23]  E. R. Davies,et al.  Machine vision - theory, algorithms, practicalities , 2004 .

[24]  Anil K. Jain,et al.  A Survey of Automated Visual Inspection , 1995, Comput. Vis. Image Underst..

[25]  Bruce G. Batchelor,et al.  Automated Visual Inspection , 1985 .

[26]  Alper Baykut,et al.  Real-time Defect Inspection of Textured Surfaces , 2000, Real Time Imaging.