A method of accumulating an image of a specimen using a scanning-type
microscope, comprising the following steps: poviding a beam of
radiation that is directed from a source through an illuminator so as to irradiate the specimen; poviding a
detector for detecting a flux of
radiation emanating from the specimen in response to said
irradiation; causing said beam to undergo scanning motion relative to a surface of the specimen, and recording an output of the
detector as a function of scan position, which method additionally comprises the following steps: in a first sampling session S1 , gathering
detector data from a first collection P1 of sampling points distributed sparsely across the specimen; repeating this procedure so as to accumulate a set {Pn} of such collections, gathered during an associated set {Sn} of sampling sessions, each set with a cardinality N>1; assembling an image of the specimen by using the set {Pn} as input to an integrative mathematical
reconstruction procedure, wherein, as part of said
assembly process, a mathematical registration correction is made to compensate for drift mismatches between different members of the set {Pn}.