I am a postdoctoral researcher at Stanford University working in the Artificial Intelligence Lab. I am also affiliated with the Univ. of Florence (Italy), and I am supported by a prestigious Marie Curie Fellowship from the European Commission under the FP7-PEOPLE-2013-IOF programme.
I got my Ph.D. in computer engineering, multimedia and telecommunication in 2011 and my Laurea degree in computer engineering in 2006, both from the Univ. of Florence. I also spent a quarter at the Signal and Image Processing department at Telecom ParisTech (France) in 2010.
My research interests lie at the boundary of Computer Vision and Multimedia. My current specific interests include automatic image and video annotation, large-scale visual recognition and retrieval, web mining and social media analysis.
Curriculum Vitae / ORCID / DBLP / Google Scholar / arXiv / Github
In the past two weeks I have been involved as computer vision project mentor in the Stanford Artificial Intelligence Laboratory’s OutReach Summer program (SAILORS). SAILORS is a summer camp for high school girls and it is intended to increase diversity in the field of AI. SAILORS aims to teach technically rigorous AI concepts in the context of societal impact.
Check out SAILORS blog to know more about the program. SAILORS was also recently featured in Wired.
Our paper “Knowledge Transfer for Scene-specific Motion Prediction”, by L. Ballan, F. Castaldo, A. Alahi, F. Palmieri and S. Savarese, has been accepted to ECCV 2016. A pre-print is available on arXiv.
When given a single frame of the video, humans can not only interpret the content of the scene, but also they are able to forecast the near future. This ability is mostly driven by their rich prior knowledge about the visual world, both in terms of (i) the dynamics of moving agents, as well as (ii) the semantic of the scene. We exploit the interplay between these two key elements to predict scene-specific motion patterns.
We gave a tutorial on “Image Tag Assignment, Refinement and Retrieval” at CVPR 2016, based on our survey. The focus is on challenges and solutions for content-based image retrieval in the context of online image sharing. We present a unified review on three problems: tag assignment, refinement, and tag-based image retrieval.
The slides are available on this page.
I am co-organizing the 4th Int’l Workshop on Web-scale Vision and Social Media (VSM) at ECCV 2016, with Marco Bertini (Univ. Florence, Italy), Thomas Mensink (Univ. Amsterdam, NL).
Vision and social media has recently become a very active inter-disciplinary research area, involving computer vision, multimedia, machine learning, and data mining. This workshop aims to bring together researchers in the related fields to promote new research directions for problems involving vision and social media, such as large-scale visual content analysis, search and mining.
Everything you wanted to know about image tagging, tag refinement and social image retrieval. Our paper has been (finally) accepted to ACM Computing Surveys! This is a titanic effort, by Xirong Li, Tiberio Uricchio, myself, Marco Bertini, Cees Snoek and Alberto Del Bimbo, to structure the growing literature in the field, understand the ingredients of the main works, clarify their connections and difference, and recognize their merits and limitations.
A pre-print is available on arXiv and the source code is on GitHub.
Our paper “Love Thy Neighbors: Image Annotation by Exploiting Image Metadata”, by J. Johnson*, L. Ballan* and L. Fei-Fei (* equal contribution), has been accepted to ICCV 2015. A pre-print is now available on arXiv.
Some images that are difficult to recognize on their own may become more clear in the context of a neighborhood of related images with similar social-network metadata. We build on this intuition to improve multilabel image annotation. Our model uses image metadata nonparametrically to generate neighborhoods of related images using Jaccard similarities, then uses a deep neural network to blend visual information from the image and its neighbors.
We gave a tutorial on “Image Tag Assignment, Refinement and Retrieval” at ACM MM 2015, based on our recent survey. Our tutorial focuses on challenges and solutions for content-based image retrieval in the context of online image sharing and tagging. We present a unified review on three closely linked problems: tag assignment, tag refinement, and tag-based image retrieval. We introduce a taxonomy to structure the growing literature, understand the ingredients of the main works, and recognize their merits and limitations.
We provided also an hands-on session with the main methods, software and datasets. All data, code and slides are online at: http://www.micc.unifi.it/tagsurvey
I have just given a tutorial on kNN at the Stanford Artificial Intelligence Laboratory’s Outreach Summer program (SAILORS). SAILORS is designed to expose high school students in underrepresented populations to the field of Artificial Intelligence.
The slides are available on this page and the Matlab code is also available for download. This is an updated version of the code used in class and should work also on Octave.
Our paper “A Data-Driven Approach for Tag Refinement and Localization in Web Videos”, by myself, Marco Bertini, Giuseppe Serra, Alberto Del Bimbo, has been accepted for publication in Computer Vision and Image Understanding (CVIU) and is now available online.
Alberto Del Bimbo has been also invited to present our work at the Workshop on Large-Scale Video Search and Mining at CVPR 2015.
Estimating the relevance of a specific tag with respect to the visual content of a given image and video has become the key problem in order to have reliable and objective tags. With video tag localization is also required to index and access video content properly. In this paper, we present a data-driven approach for automatic video annotation by expanding the original tags through images retrieved from photo-sharing website, like Flickr, and search engines such as Google or Bing. Compared to previous approaches that require training classifiers for each tag, our approach has few parameters and permits open vocabulary.
Watch the TED 2015 talk by my postdoc advisor Prof. Fei-Fei Li about the recent advances in computer vision, from the detection and classification of objects in images to algorithms that are able to construct natural descriptions of those images. It is an exciting overview of the current state of the art in computer vision, in which she shares her thoughts on its potential use and impact. http://goo.gl/8O5Fch