Abstract: The invention relates to an optical-computing device and method for analysing a container (12) made of transparent or translucent material by means of a polarimetric camera (18), comprising: —acquiring at least one master digital image (IM) of the container using the photoelectric sensor (22) of the polarimetric camera; —computing an intensity image (It) in which the value of each intensity pixel (Pt(n)) is an averaged value of the value of at least two pixels of the master digital image corresponding to two circular analyses in opposite directions to one another, or two linear analyses of orthogonal polarisation axes or two orthogonal elliptical analyses; —computing at least one phase-shift image (ID) by calculating, for a series of composite pixels, a phase-shift pixel (Pd(n)) from the value of a set of one or more partial pixel(s) (Ppk(n)) belonging to a combination of one or more partial images (Ipk).