Corrosion Grade Evaluation of Carbon Steel Based on Digital Image Analysis

The corrosion binary image of carbon steel was obtained from its digital image by the process of enhancingcontrast,denoising and binarizing.And then the corrosion grade was determined from the calculation and analysis ofthe corrosion area.The calculation of the final corrosion area from the binary image whose contrast was enhanced bythe method of combining local enhancement with Gamma correction and proportioning histogram shows that:althoughthe proportioning hisitogram can improve the contrast,it can not eliminate the shadow generated from the nonuniformillumination,leading a large deviation of the calculated results from the actual corrosion area;However,combininglocal enhancement with Gamma correction can eliminate the adverse effect of nonuniform illumination.