There is provided a system of examination of a semiconductor specimen, comprising a processor and memory circuitry configured to obtain, for each given candidate defect of a plurality of candidate defects in an image of the specimen, a given area of the given candidate defect in the image, obtain a reference image, perform a segmentation of at least part of the reference image, to determine, for each given candidate defect, first reference areas in the reference image matching a given reference area corresponding to the given area, select among the first reference areas, a plurality of second reference areas, obtain a plurality of corresponding second areas in the image, and use data informative of a pixel intensity of the second areas and data informative of a pixel intensity of the given area to determine whether the given candidate defect corresponds to a defect.