A computer implemented method for learning a function configured for captioning a region of an image. The method comprises providing a dataset of triplets each including a respective image, a respective region of the respective image, and a respective caption of the respective region. The method also comprises learning, with the dataset of triplets, a function that is configured to generate an output caption based on an input image and on an input region of the input image. Such a method constitutes an improved solution for captioning a region of an image.