Cees Snoek

The paper Balancing Thread Based Navigation for Targeted Video Search by Ork de Rooij, Cees Snoek, and Marcel Worring is available online now. Various query methods for video search exist. Because of the semantic gap each method has its limitations. We argue that for effective retrieval query methods need to be combined at retrieval time. However, switching query methods often involves a change in query and browsing interface, which puts a heavy burden on the user. In this paper, we propose a novel method for fast and effective search through large video collections by embedding multiple query methods into a single browsing environment. To that end we introduced the notion of query threads, which contain a shot-based ranking of the video collection according to some feature-based similarity measure. On top of these threads we define several thread-based visualizations, ranging from fast targeted search to very broad exploratory search, with the ForkBrowser as the balance between fast search and video space exploration. We compare the effectiveness and efficiency of the ForkBrowser with the CrossBrowser on the TRECVID 2007 interactive search task. Results show that different query methods are needed for different types of search topics, and that the ForkBrowser requires signifficantly less user interactions to achieve the same result as the CrossBrowser. In addition, both browsers rank among the best interactive retrieval systems currently available.

The paper A Comparison of Color Features for Visual Concept Classification by Koen van de Sande, Theo Gevers, and Cees Snoek is available online now. The paper improves upon the CVPR 2008 paper below by considering also the points at which color features are extracted. Hence, different point sampling strategies based on Harris-Laplace salient points, dense sampling and the spatial pyramid are studied in concert with color features.