The present invention relates to a low-coherence interferometer apparatus or device (100, 200) for determining information on the structure and/or the location of interfaces of an object (13) comprising: a polychromatic light source (11)； an optical system for generating a measurement optical beam and a reference optical beam； a delay line (14) for introducing a variable optical delay between the measurement optical beam and the reference optical beam； a detection optic (15) for combining the measurement optical beam and the reference optical beam, and for producing a spectral signal representative of an optical-power spectral density of the resulting interference signal； a processing and controlling module (16) arranged to acquire a plurality of spectral signals for a plurality of optical delays, to determine, for each spectral signal, information on the optical lag between interfering beams in a measurement range called the spectral measurement range, to analyse the variation in said optical lags as a function of the optical delay and to assign the one or more optical lags determined on the basis of the various spectral signals to one or more what are called interface curves (521, 522, 523, 524), corresponding to straight lines of positive, negative, zero or almost-zero gradient, depending on the respective optical delay of the acquisition of said spectral signals, and to deduce therefrom information on the structure and/or the location of interfaces of the object (13). The invention also relates to a method implemented in this device or this apparatus.La présente invention concerne un dispositif ou appareil interféromètre à faible cohérence (100, 200) pour déterminer des informations sur la structure et/ou la localisation d'interfaces d'un objet (13) comprenant: une source de lumière (11) polychromatique； un système optique pour générer un faisceau optique de mesure et un faisceau optique de référence； une ligne à retard (14) pour introduire un délai optique vari
