Title
Wavelet-based defect detection in solar wafer images with inhomogeneous texture
Abstract
Solar power is an attractive alternative source of electricity. Multicrystalline solar cells dominate the market share owing to their lower manufacturing costs. The surface quality of a solar wafer determines the conversion efficiency of the solar cell. A multicrystalline solar wafer surface contains numerous crystal grains of random shapes and sizes in random positions and directions with different illumination reflections, therefore resulting in an inhomogeneous texture in the sensed image. This texture makes the defect detection task extremely difficult. This paper proposes a wavelet-based discriminant measure for defect inspection in multicrystalline solar wafer images. The traditional wavelet transform techniques for texture analysis and surface inspection rely mainly on the discriminant features extracted in individual decomposition levels. However, these techniques cannot be directly applied to solar wafers with inhomogeneous grain patterns. The defects found in a solar wafer surface generally involve scattering and blurred edges with respect to clear and sharp edges of crystal grains in the background. The proposed method uses the wavelet coefficients in individual decomposition levels as features and the difference of the coefficient values between two consecutive resolution levels as the weights to distinguish local defects from the crystal grain background, and generates a better discriminant measure for identifying various defects in the multicrystalline solar wafers. Experimental results have shown the proposed method performs effectively for detecting fingerprint, contaminant, and saw-mark defects in solar wafer surfaces.
Year
DOI
Venue
2012
10.1016/j.patcog.2011.07.025
Pattern Recognition
Keywords
Field
DocType
wavelet-based defect detection,multicrystalline solar wafer image,inhomogeneous texture,individual decomposition level,multicrystalline solar wafer surface,multicrystalline solar wafer,solar cell,solar wafer surface,solar wafer,solar power,multicrystalline solar cell,wavelet transform
Energy conversion efficiency,Wafer,Pattern recognition,Optics,Solar power,Fingerprint,Solar cell,Scattering,Artificial intelligence,Mathematics,Wavelet transform,Wavelet
Journal
Volume
Issue
ISSN
45
2
0031-3203
Citations 
PageRank 
References 
18
0.79
22
Authors
2
Name
Order
Citations
PageRank
Wei-Chen Li1544.03
Du-Ming Tsai297068.17