Manfred Del Fabro

The Video Browser Showdown: a live evaluation of interactive video search tools

The Video Browser Showdown evaluates the performance of exploratory video search tools on a common data set in a common environment and in presence of the audience. The main goal of this competition is to enable researchers in the field of interactive video search to directly compare their tools at work. In this paper, we present results from the second Video Browser Showdown (VBS2013) and describe and evaluate the tools of all participating teams in detail. The evaluation results give insights on how exploratory video search tools are used and how they perform in direct comparison. Moreover, we compare the achieved performance to results from another user study where 16 participants employed a standard video player to complete the same tasks as performed in VBS2013. This comparison shows that the sophisticated tools enable better performance in general, but for some tasks common video players provide similar performance and could even outperform the expert tools. Our results highlight the need for further improvement of professional tools for interactive search in videos.

Keyframe extraction in endoscopic video

In medical endoscopy more and more surgeons archive the recorded video streams in a long-term storage. One reason for this development, which is enforced by law in some countries, is to have evidence in case of lawsuits from patients. Another more practical reason is to allow later inspection of previous procedures and also to use parts of such videos for research and for training. However, due to the dramatic amount of video data recorded in a hospital on a daily basis, it is very important to have good preview images for these videos in order to allow for quick filtering of undesired content and for easier browsing through such a video archive. Unfortunately, common shot detection and keyframe extraction methods cannot be used for that video data, because these videos contain unedited and highly similar content, especially in terms of color and texture, and no shot boundaries at all. We propose a new keyframe extraction approach for this special video domain and show that our method is significantly better than a previously proposed approach.

Instant Video Browsing: A Tool for Fast Non-sequential Hierarchical Video Browsing

We introduce an easy-to-use video browsing tool which assists users in getting a quick overview of videos as well as in finding segments of interest. It provides a parallel and a tree-based view for browsing the content of videos - or even video collections - in a hierarchical, non-sequential manner. The tool has a plug-in architecture and can be extended both by further presentation methods and by video analysis algorithms.

Why did you take this photo: a study on user intentions in digital photo productions

Why do people take pictures? While substantial work has been done on the intentions of people producing photos in specific domains (e.g. Flickr users or mobile phone cameras) the general case - arbitrary users taking photos with arbitrary devices - has not yet been investigated in detail. In this short paper, we present an exploratory study on the intentions and goals of people taking digital photos. 40 different specific photo taking situations of 10 people where investigated. We classified the situations and reflected them into context of existing work to investigate the applicability and usefulness of classifications existing for specific domains. Our findings show that applicability of existing models for small domains is limited and they indicate the need of a generalized taxonomy. We further identify hypotheses and research questions for future work in this area.

Summarization and presentation of real-life events using community-contributed content

We present an algorithm for the summarization of social events with community-contributed content from Flickr and YouTube. A clustering algorithm groups content related to the searched event. Date information, GPS coordinates, user ratings and visual features are used to select relevant photos and videos. The composed event summaries are presented with our video browser.

AAU video browser: non-sequential hierarchical video browsing without content analysis

We participate in the Video Browser Showdown with our easy-to-use video browsing tool. It can be used for getting a quick overview of videos as well as for simple Known Item Search (KIS) tasks. It offers a parallel and a tree-like browsing interface for navigating through the content of single videos or even small video collections in a hierarchical, non-sequential manner. We want to validate whether simple KIS tasks can be completed without a time consuming content analysis in advance.

Hierarchical video browsing with a 3D carousel

We present a video browsing tool that combines advantages of the hierarchical browsing concept with 3D projection and multi-threaded programming in order to provide a convenient and efficient interface. The tool allows for instantaneous hierarchical browsing of video and uses a dynamic approach (i.e. tree of playable video segments instead of static key frames)that also supports parallel playback.

Video Scene Detection Based on Recurring Motion Patterns

We present an algorithm for video scene detection based on the identification of recurring motion patterns within a video stream. The motion information is extracted in the compressed domain of H.264/AVC videos, no full decoding of the video stream is needed. Based on the motion information our algorithm identifies sequences of adjacent frames with similar motion. Throughout all identified motion sequences we are searching for recurring patterns. The pattern recurring most often is used for the segmentation of the video stream into scenes. The evaluation shows promising results.

Dynamic Hierarchical Visualization of Keyframes in Endoscopic Video

The after-inspection of endoscopic surgeries can be a tedious and time consuming task. Physicians have to search for important segments in the video recording of an intervention, which may have a duration of several hours. Automatically selected keyframes can support physicians in this task. The problem is that either too few keyframes are selected, missing some important information, or too many keyframes are selected, which overwhelms the user. Furthermore, keyframes of endoscopic videos typically show highly similar content. It is hence difficult to keep track of the temporal context of selected keyframes if they are presented in a grid view. To overcome these limitations, we present a dynamic hierarchical browsing technique for large sets of keyframes that preserves the temporal context in the visualization of the frames.

Interactive Evaluation of Video Browsing Tools

The Video Browser Showdown (VBS) is a live competition for evaluating video browsing tools regarding their efficiency at known-item search (KIS) tasks. The first VBS was held at MMM 2012 with eight teams working on 14 tasks, of which eight were completed by expert users and six by novices. We describe the details of the competition, analyze results regarding the performance of tools, the differences between the tasks and the nature of the false submissions.