This book focuses on design and development of a unified framework for radiographic image analysis and interpretation with emphasis on defect classification. The framework is constructed by creating two ontologies namely process ontology and domain ontology. Process ontology structures information for performing gray scale image analysis and it is maintained as a knowledgebase. The images are analyzed by using the process plan which resulted in the enhanced images from which geometrical, statistical and textural features are extracted to construct domain ontology. In addition to that, details of welding defects in radiographic image are conceptualized and maintained in the domain ontology. The framework includes a flexible user interface through which the experts' knowledge of the domain can be uploaded into the knowledgebase. The knowledgebase search is minimized into single selection on the domain ontology using which the entire content of defects and type of defect appearing in the image can be visualized. The performance study shows that the developed unified framework outperformed the other two models viz. neural and statistical with respect to classification of defects.