The surface defects are loosely separated into two types. One is local textural irregularities which is the main concern for most visual surface inspection applications. The other is global deviation of colour and/or texture, where local pattern or texture does not exhibit abnormalities. The second type of defects have been largely neglected until recently, particularly when colour imaging system has been widely used in visual inspect ion and where chromatic consistency plays an important role in quality control. The techniques used to inspect textural abnormalities are discussed in four categories, statistical approaches, structural approaches, filter based methods, and model based approaches, with a comprehensive list of references to some recent works. Due to rising demand and practice of colour texture analysis in application to visual inspection, those works that are dealing with colour texture analysis are discussed separately. It is also worth noting that processing vector-valued data has its unique challenges, which conventional surface inspection methods have often ignored or do not encounter. In existing system optical microscopy is used for surface inspection to capture high-resolution images, although it has limited field of view and is more suitable for small samples. In this existing system the resolutions of the images obtained are much lower as compared to images from microscopy. In this project, a contrast-adjusted Otsu’s method and contrast-adjusted median-based Otsu’s method is proposed. he threshold for median-based MET is selected using similar set of rule for finding the optimum threshold using MET.