1. A computer-implemented method for use in conjunction with critical dimensions metrology of a semiconductor structure, the method comprising: obtaining an image of the semiconductor structure, said semiconductor structure including a plurality of similar structural elements, said plurality of similar structural elements including at least a first group and a second group of similar structural elements, each group of similar structural elements originating from a different manufacturing stage; identifying a sufficient number of structural elements belonging to the first group and a sufficient number of structural elements belonging to the second group; assessing to each given structural element within said sufficient number of elements in the first group and in the second group one or more features indicative of a respective manufacturing stage, wherein values of the respective features are derived from the obtained image, thus giving rise to assessment results; and using said assessment results for a classification decision related to manufacturing stages and respectively originating therefrom structural elements in the first group and in the second group of similar structural elements.