Research of image processing method on alage conolized on the insulator surface

Algae have recently been colonized on insulator surfaces, especially on surfaces of composite and RTV-coated insulators installed in warm and humid regions. The adverse effect produced by algae on hydrophobicity, flashover characteristics, and the material performance of insulators has been previously demonstrated in the laboratory. However, previous studies have not explored the research method for measuring the degree of growth to determine the severity of the effect of algae on insulators. A new kind of image processing method based on color segmentation is presented to discriminate the distribution of algae on the insulator surface. Two main procedures are included in this method. First, the unambiguous insulator images are obtained using a digital camera presupposed with a white balance. Second, the green algae pixels are recognized and extracted from the insulator images through a specific MATLAB program, which is determined to be capable of discriminating the algae distribution and calculating the algae coverage rate and characteristic green value. The insulators acquired from the 500-kV DC transmission lines have been considered for this study. Results show that the growth degree of algae was more serious on RTV-coated insulators than on composite insulators.