Device and method for inspecting a hair sample

A device for inspecting a scalp surface of a user, the device comprising a housing in which an image sensor is arranged to receive measurement light emitted from a measuring area configured to accommodate a keratinous surface of the scalp surface, the image sensor configured to acquire an image of the scalp surface that includes the keratinous surface through a measurement window in a front wall of the housing, over a corresponding imaging light path, the device being further equipped with an illumination ring arranged in the housing rear of the measurement window around the imaging light path, said illumination ring having two opposed partially peripheral illumination portions extending over a sector of 30 to 60° and separated by two opposed complementary partially peripheral non-illuminating portions, the illumination portions being further configured to illuminate the measuring area by directing light emitted from the illumination portions from rear of the measurement window through the measurement window to the measuring area over an illumination light path, said illumination light path having an angle of incidence of 45° so as to form a 45:0 measurement configuration, wherein the device is configured so that both illumination portions may be on when the image is taken.