REPORT Lebret_Idiap-RR-08-2015/IDIAP Phrase-based Image Captioning Lebret, Rémi Pinheiro, Pedro H. O. Collobert, Ronan EXTERNAL https://publications.idiap.ch/attachments/reports/2015/Lebret_Idiap-RR-08-2015.pdf PUBLIC Idiap-RR-08-2015 2015 Idiap May 2015 Under review by the International Conference on Machine Learning (ICML). Generating a novel textual description of an image is an interesting problem that connects computer vision and natural language processing. In this paper, we present a simple model that is able to generate descriptive sentences given a sample image. This model has a strong focus on the syntax of the descriptions. We train a purely bilinear model that learns a metric between an image representation (generated from a previously trained Convolutional Neural Network) and phrases that are used to described them. The system is then able to infer phrases from a given image sample. Based on caption syntax statistics, we propose a simple language model that can produce relevant descriptions for a given test image using the phrases inferred. Our approach, which is considerably simpler than state-of-the-art models, achieves comparable results in two popular datasets for the task: Flickr30k and the recently proposed Microsoft COCO.