Large-Scale Multimedia Data Collections

T he widespread adoption of smartphones equipped with high-quality image-capturing capabilities coupled with the prevalent use of social networks have resulted in an explosive growth of social media content. People now routinely capture the scenes around them and instantly share the multimedia content with their friends over a variety of social networks. The social network functions also ensure that much of this content comes with some form of social annotations. This environment sets the stage for advances in large-scale media research. It is now easy to gather a huge database of images with social annotations. A resulting challenge then is the design of appropriate tasks to motivate advanced research in new directions. This involves both fundamental studies of use cases and task design methodologies as well as the development of new datasets to cater to different needs. Given the large quantities of data, acquiring ground truth becomes a tedious and challenging endeavor. The current trend is toward leveraging crowdsourcing platforms such as Amazon Mechanical Turk to help gather ground truth. However, these methods could result in incomplete and/or unreliable ‘‘ground truth.’’ In addition, given large-scale datasets, a variety of research, both intended and emerging, will be carried out on these datasets. Thus, questions regarding the reusability and repurposing of datasets to different research needs will arise. Finally, in this rapidly changing environment, how can we anticipate and plan for new directions in large-scale multimedia research? This special issue hopes to address these challenges. The call for this special issue was launched after the successful conclusion of the ACM Workshop on Very-Large-Scale Multimedia Corpus, Mining, and Retrieval at the ACM Multimedia 2011 Conference. The articles in this issue cover identification of use cases and task design, dataset development, and basic research over existing datasets. (For more information, visit http://youtu.be/0OtXnqe67Ns to view a video of us discussing the importance of largescale multimedia collections.)