ILLUMINATION ADUSTMENT FOR BRIDGE COATING IMAGES USING BEMD-MORPHOLOGY APPROACH

  • Po-Han Chen (School of Civil and Environmental Engineering, Nanyang Technological University) ;
  • Ya-Ching Yang (Nanyang Technological University, Singapore and National Taiwan University) ;
  • Luh-Maan Chang (Dept. of Civil Engineering, National Taiwan University)
  • Published : 2009.05.27

Abstract

Digital image recognition has been used for steel bridge surface assessment since late 1990s. However, the non-uniform illumination problems such as shades, shadows, and highlights are still challenges in image processing to date. Therefore, this paper develops a new approach to tackle the non-uniform illumination problem for rust image adjustment. The inhomogeneous illumination problem is divided into shades/shadows and highlights in this paper. The proposed BEMD-morphology approach (BMA) utilizes the bidimensional empirical mode decomposition to mitigate the shade/shadow effect, and the morphological processing to detect and replace the highlight area. Finally, the rust image processed with the BMA will be segmented by the K-Means algorithm, one of the most popular and effective methods, to show the effectiveness of illumination adjustment.

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