The increase in dearth of image analysis and interpretation in the field of remote sensing, communication, medical imaging, forensics and industrial inspection demands for a complete automated image processing system. Especially, automating the process of region of interest extraction is a great challenge as it depends completely on the domain information. Many of the researchers had attempted to automate the process of image interpretation and classification only. In particular, automating ROI extraction process in greyscale images containing weld defects had demonstrated great difficulty towards the accuracy. This paper attempted to address the issue of complete automation of greyscale image ROI extraction for further image analysis and classification. The attempt also outlines the necessity of segregating background and foreground images in industrial radiographs through a new intensity-based filtering method. A study is made to determine an appropriate segmentation method for different defect detection. In order to evaluate the designed methodology, industrial radiographs containing defects of welding process are considered. Copyright © 2014 Inderscience Enterprises Ltd.