A method of accumulating an image of a specimen using a scanning-type microscope, comprising the following steps: - Directing a beam of radiation from a source through an illuminator so as to irradiate a surface S of the specimen; - Using a detector to detect a flux of radiation emanating from the specimen in response to said irradiation; - Causing said beam to follow a scan path relative to said surface; - For each of a set of sample points in said scan path, recording an output D n of the detector as a function of a value P n of a selected measurement parameter P, thus compiling a measurement set M = {(D n, P n)}, where n is a member of an integer sequence; - Using computer processing apparatus to automatically deconvolve the measurement set M and spatially resolve it so as to produce reconstructed imagery of the specimen, wherein, considered at a given point p i within the specimen, the method comprises the following steps: - In a first probing session, employing a first beam configuration B 1 to irradiate the point p i with an associated first Point Spread Function F 1, whereby said beam configuration is different to said measurement parameter; - In at least a second probing session, employing a second beam configuration B 2 to irradiate the point p i with an associated second Point Spread Function F 2, whereby: ▪ F 2 overlaps partially with F 1 in a common overlap zone O i in which point p i is located; ▪ F 1 and F 2 have respective non-overlapping zones F 1 ' and F 2 ' outside of O i, - Using a Source Separation algorithm in said computer processing apparatus to perform image reconstruction in said overlap zone O i considered separately from said non-overlapping zones F 1 ' and F 2 '; wherein - Said surface is defined to extend parallel to an XY-plane of a Cartesian coordinate system XYZ; - Said beam configuration is chosen to be a Z-position of a point of entry of the beam into the specimen; - Between said first and second probing sessions, a physical slicing procedure is used to remove a layer of material of thickness L from an initial surface S 1, thereby exposing a new surface S 2; and - Point Spread Functions F 2 and F 1 are displaced relative to one another in said Z-direction by an amount L. - Directing a beam of radiation from a source through an illuminator so as to irradiate a surface S of the specimen; - Using a detector to detect a flux of radiation emanating from the specimen in response to said irradiation; - Causing said beam to follow a scan path relative to said surface; - For each of a set of sample points in said scan path, recording an output D n of the detector as a function of a value P n of a selected measurement parameter P, thus compiling a measurement set M = {(D n, P n)}, where n is a member of an integer sequence; - Using computer processing apparatus to automatically deconvolve the measurement set M and spatially resolve it so as to produce reconstructed imagery of the specimen, - In a first probing session, employing a first beam configuration B 1 to irradiate the point p i with an associated first Point Spread Function F 1, whereby said beam configuration is different to said measurement parameter; - In at least a second probing session, employing a second beam configuration B 2 to irradiate the point p i with an associated second Point Spread Function F 2, whereby: ▪ F 2 overlaps partially with F 1 in a common overlap zone O i in which point p i is located; ▪ F 1 and F 2 have respective non-overlapping zones F 1 ' and F 2 ' outside of O i, ▪ F 2 overlaps partially with F 1 in a common overlap zone O i in which point p i is located; ▪ F 1 and F 2 have respective non-overlapping zones F 1 ' and F 2 ' outside of O i, - Using a Source Separation algorithm in said computer processing apparatus to perform image reconstruction in said overlap zone O i considered separately from said non-overlapping zones F 1 ' and F 2 '; - Said surface is defined to extend parallel to an XY-plane of a Cartesian coordinate system XYZ; - Said beam configuration is chosen to be a Z-position of a point of entry of the beam into the specimen; - Between said first and second probing sessions, a physical slicing procedure is used to remove a layer of material of thickness L from an initial surface S 1, thereby exposing a new surface S 2; and - Point Spread Functions F 2 and F 1 are displaced relative to one another in said Z-direction by an amount L.