Semi-automatic photo annotation strategies using event based clustering and clothing based person recognition

Managing a large number of digital photos is a challenging task for casual users. Personal photos often don't have rich metadata, or additional information associated with them. However, available metadata can play a crucial role in managing photos. Labeling the semantic content of photos (i.e., annotating them), can increase the amount of metadata and facilitate efficient management. However, manual annotation is tedious and labor intensive while automatic metadata extraction techniques often generate inaccurate and irrelevant results. This paper describes a semi-automatic annotation strategy that takes advantage of human and computer strengths. The semi-automatic approach enables users to efficiently update automatically obtained metadata interactively and incrementally. Even though automatically identified metadata are compromised with inaccurate recognition errors, the process of correcting inaccurate information can be faster and easier than manually adding new metadata from scratch. In this paper, we introduce two photo clustering algorithms for generating meaningful photo groups: (1) Hierarchical event clustering; and (2) Clothing based person recognition, which assumes that people who wear similar clothing and appear in photos taken in one day are very likely to be the same person. To explore our semi-automatic strategies, we designed and implemented a prototype called SAPHARI (Semi-Automatic PHoto Annotation and Recognition Interface). The prototype provides an annotation framework which focuses on making bulk annotations on automatically identified photo groups. The prototype automatically creates photo clusters based on events, people, and file metadata so that users can easily bulk annotation photos. We performed a series of user studies to investigate the effectiveness and usability of the semi-automatic annotation techniques when applied to personal photo collections. The results show that users were able to make annotations significantly faster with event clustering using SAPHARI. We also found that users clearly preferred the semi-automatic approaches. (C) 2007 Elsevier B.V. All rights reserved.