Effectiveness of neuro-fuzzy recognition approach in evaluating steel bridge paint conditions

The development of digital image recognition techniques has contributed to increased precision in pattern recognition and led to numerous applications in industries. In September 1999, the Indiana Department of Transportation (INDOT) first tried out digital image recognition techniques to steel bridge coating assessment. The purpose of this tryout was to obtain a rust percentage, which was required in the INDOT bridge painting warranty contract, when conducting steel bridge coating investigation. Despite the advantages of digital image recognition, some problems that may cause inaccurate recognition results still exist. Nonuniform illumination (i.e., brightness or darkness or shadow) is one of them. The neuro-fuzzy recognition approach (NFRA) was developed to minimize the effect of nonuniform illumination. In this technical note, the framework of NFRA, its application to steel bridge coating assessment, and its performance comparison to three other image recognition methods will be presented.Key words: neuro-fuzzy recognition approach (NFRA), artificial neural network (ANN), double sampling plan, multiresolution pattern classification (MPC), iterated conditional modes (ICM).