A defect in an image of a semiconductor wafer can be classified as an initial defect type based on the pixels in the image. Critical dimension uniformity parameters associated with the defect type can be retrieved from an electronic data storage unit. A level of defectivity of the defect can be quantified based on the critical dimension uniformity parameters. Defects also can be classified based on critical dimension attributes, topography attributes, or contrast attributes to determine a final defect type.