1. An apparatus for acquiring a two-dimensional image of an external surface of a three-dimensional object, comprising: a conveyor for supporting and displacing the object along a path; a camera for capturing images of portions of the object surface; a friction member for rotating the object about an axes of rotation to vary the object surface that is exposed to the camera to provide a plurality of exposed portions of the object surface, wherein the camera is configured to capture images corresponding to the exposed portions of the object surface, and wherein the camera is configured to capture the images as respective single frames; and an electronic control unit adapted, for each single frame, to: read out a sub-frame from the single frame, the sub-frame corresponding to a respective individual portion of the exposed portion of the object surface, whereby the sub-frames correspond to individual portions of the object surface; and assemble the sub-frames into an assembled frame corresponding to a two-dimensional image of a surface area of the object, wherein the object is a capsule of the type used in pharmaceutical or healthcare applications, the conveyor includes at least one carrier provided with a housing configured to receive the object and a driving member adapted to move the carrier relative to the friction member, and the friction member is arranged to contact locally the external surface of the object when the object is placed in the housing of the carrier.