The invention relates to a method for correcting an optical signal produced by a sample comprising the following steps: illuminating a surface of the sample by a first light beam, produced by a first light source, the said first light source being coupled to a first optical system, focusing the said first light beam in an object focal plane of the first optical system, the said object focal plane being situated, in the sample, at a measuring depth z from the surface of the sample; measuring, with a first photodetector, of a first optical signal backscattered by the sample in response to the first light beam, the first photodetector producing a first measured signal representative of the said first optical signal, a spatial filter being interposed between the first optical system and the first photodetector, the spatial filter comprising a window which transmits the said first optical signal towards the said first photodetector, the window being disposed in a conjugate focal plane of the object focal plane of the first optical system; wherein the method also comprises the following steps: determining an optical scattering property of the sample; applying a correction function to the first measured signal so as to generate a first corrected signal, the said correction function taking into account the said optical scattering property.