The invention relates to a system (1) for conveying articles (3), which system comprises an article conveyor (2) extending from an upstream end (4) to a downstream end (5), and a motor-driven shuttle trolley (6) having an article carrier deck (7) and designed to dock with said ends of the conveyor so as to transfer an article between the trolley and the conveyor. The conveyor is a gravity conveyor under which a ramp (12) extends, and the trolley is suitable for travelling under the conveyor and is provided with a lever (11) that is mounted to move vertically relative to the deck and that is designed to co-operate with the ramp while the trolley is moving under the conveyor so that, by following the ramp, the lever moves between a retracted position in which it is retracted under the conveyor and a deployed position in which it projects above the conveyor so as to drive an article along the conveyor. The method of matching digital images of the same article in a data processor unit comprises the steps of: transforming each digital image of an article into a local divergence topographic map of the luminance gradient vector field; detecting singularities or extrema of local divergence in the luminance gradient vector field, such singularities corresponding to points of interest in said digital image; and, for each detected point of interest, encoding the values for the singularity of the gradient field that are located on a plurality of concentric rings centered on the point of interest so as to derive a digital data vector (210); and transforming said vector into a digital hash key (220) by means of a family of hash functions of the cosine Locality-Sensitive Hashing (LSH) type.