1. A method of data acquisition for an apparatus having a Scanning Electron Microscope (SEM) for microscopic imaging and a Focused Ion Beam (FIB) unit for sample milling, the method comprising: scanning a sample with the SEM to obtain an image region (I C R ); analyzing the image region with a classifier function (h i ) that operates on the image region and returns a classification image whose content depends on whether the classifier estimates that a pixel in the image region belongs to a determined target structure or not; searching in the classification image for disjoint regions that indicate potential target locations and adding the regions so found to a list of candidates; iterating the steps of scanning, analyzing and searching on the members of the list of candidates.