Publications by Rita Cucchiara

This paper presents an effective system for streaming over low-capacity networks (such as GPRS and EGPRS) of live videos with low latency. Existing solutions are either too complex or not suitable to our scope. For this reason, we developed a complete, ready-to-use streaming system based on H.264/AVC codec and UDP/IP stack. The system employs adaptive controls to achieve the best tradeoff between low latency and good video fluency, by keeping the UDP buffer occupancy at the decoder side between two given levels. Our experiments demonstrate that this system is able to transmit live videos at CIF format and 10 fps over GPRS/EGPRS with very low latency (1.73 sec on average, basically due to the network delay), good fluency and average quality, measured with PSNR, of 31 dB on GPRS at 23 kbps at 10 fps.

Effective usage of multimedia digital libraries has to deal with the problem of building efficient content annotation and retrieval tools. MOM (Multimedia Ontology Manager) is a complete system that allows the creation of multimedia ontologies, supports automatic annotation and creation of extended text (and audio) commentaries of video sequences, and permits complex queries by reasoning on the ontology.

A system for the automatic creation of Pictorially Enriched Ontologies is presented, that is ontologies for context-based video digital libraries, enriched by pictorial concepts for video annotation, summarization and similarity-based retrieval. Extraction of pictorial concepts with video clips clustering, ontology storing with MPEG-7, and the use of the ontology for stored video annotation are described. Re-sults on sport videos and TRECVID2005 video material are reported.

Multimedia surveillance relates to the exploitation of multimedia tools for retrieving information from surveillance data, for emerging applications such as video post-analysis for forensic purposes. Searching for all the sequences in which a certain person was present is a typical query that is carried out by means of example images. Unfortunately, surveillance cameras often have low resolution, making retrieval based on appearance difficult. This paper proposes to exploit a two-step retrieval process that merges similarity-based retrieval with multicamera tracking-based retrieval able to create consistent traces of a person from different views and, thus, different resolutions. A mixture model is used to summarize these traces into a single prototype on which retrieval is performed. Experimental results demonstrate the accuracy of the retrieval process also in the case of varying illumination conditions.

In this DEMO, we present a tool set for video digital library management that allows i) structural annotation of edited videos in MPEG-7 by automatically extracting shots and clips; ii) automatic semantic annotation based on perceptual similarity against a taxonomy enriched with pictorial concepts iii) video clip access and hierarchical summarization with stand-alone and web interface iv) access to clips from mobile platform in GPRS-UMTS videostreaming. The tools can be applied in different domain-specific Video Digital Libraries. The main novelty is the possibility to enrich the annotation with pictorial concepts that are added to a textual taxonomy in order to make the automatic annotation process more fast and often effective. The resulting multimedia ontology is described in the MPEG-7 framework. The PEANO (Perceptual Annotation of Video) tool has been tested over video art, sport (Soccer, Olimpic Games 2006, Formula 1) and news clips.

In this work, we describe in detail the MPEG-7 Shape Spectrum Descriptor and provide a set of tests with different 3D objects databases. To verify if the literature reported low performance of this descriptor were due to the comparison employed, we also used the Earth Movers Distance which allows much more detailed histograms comparisons. Finally we compare our outcomes with the best results in related work.

This paper describes a system for motion detection based on background suppression,specifically conceived for working in complex scenes with vacillating background,camouflage, illumination changing, etc.. The system contains proper techniques for background bootstrapping, shadow removal, ghost suppression and selective updating of the background model. The results on the challenging videos provided in VSSN '06 Open Source Algorithm Competition dataset demonstrate that the proposed system outperforms the widely-used mixture-of-Gaussians approach.

In semantic video adaptation measures of performance must consider the impact of the errors in the automatic annotation over the adaptation in relationship with the preferences and expectations of the user. In this paper, we define two new performance measures Viewing Quality Loss and Bit-rate Cost Increase, that are obtained from classical peak signal-to-noise ration (PSNR) and bit rate, and relate the results of semantic adaptation to the errors in the annotation of events and objects and the user's preferences and expectations. We present and discuss results obtained with a system that performs automatic annotation of soccer sport video highlights and applies different coding strategies to different parts of the video according to their relative importance for the end user. With reference to this framework, we analyze how highlights' statistics and the errors of the annotation engine influence the performance of semantic adaptation and reflect into the quality of the video displayed at the user's client and the increase of transmission costs.

This paper addresses multimedia tools for universal multimedia access to sports videos by means of automatic annotation and content-based adaptation. The goal is to provide boosting technologies to allow the new generations of mobile devices (phones and PDAs) to better exploit the available bandwidth and to achieve a reasonable cost/quality trade-off in remote access to long-lasting live events, such as sport competitions. Although the available bandwidth for mobile communication has increased thanks to new telecommunication standards such as GPRSand UMTS, it is still insufficient for high quality video transmission. The limited resources of low-cost terminals and the high costs of data transfer hinder de-facto many possible multimedia services. First, the quality is limited by the small display size and memory available on many mobile devices. Second, the limited bandwidthmay affect user satisfaction either because of the time spent waiting for the download or the latency in streaming a live video. Moreover, even if the user is willing to wait for the download or accepts frame dropping, a reduction of data to send would be unavoidable in order to bring down the costs of the service. As a matter of fact, most telecommunication companies charge a fee proportional to the number of bytes transferred. Hence, the cost of accessing a long-lasting live video, such as a 90-minute soccer competition, is stilltoo high for most users.

It is with considerable pride that we present this special issue of ACM multimedia based on the presentations at the third Video Surveillance and Sensor Network workshop, in conjunction with the ACM conference in Singapore 2005. The papers were thoroughly reviewed independently of the review process for the workshop. This special issue consists of eight papers drawn from a number of areas. It appears that we are breaking new ground as explained in this issue.Whenever we say multimedia, we think of systems and services that manage heterogeneous data for human-oriented applications; human users are normally the subjects who access and use multimedia data, multimediastreams, multimedia content, and multimedia interfaces in many different applications contexts. Following this abstraction, multimedia surveillance systems would be only a surveillance system able to produce output of the task in a multimedia format, providing distilled video, images and sounds of the monitored environment, which would possibly be annotated in an efficient and standard way or possibly transcoded in another media such as text or animation, to improve further querying to surveillance stored data.