Disclosed is a method for training a neural network, for the recognition of a sequence of characters in an image and without a predefined format, including: a step of creating an artificial database of a plurality of sequences of characters in images, some sequences being generated randomly, other sequences being derived from transformations of sequences generated randomly; a learning step that teaches the neural network to recognize a sequence of characters in an image, directly on at least some of the sequences of the artificial database, without a preliminary subdividing of these sequences into their component characters.