Giani David Silva

SAPTE: A multimedia information system to support the discourse analysis and information retrieval of television programs

This paper presents a novel multimedia information system, called SAPTE, for supporting the discourse analysis and information retrieval of television programs from their corresponding video recordings. Unlike most common systems, SAPTE uses both content independent and dependent metadata, which are determined by the application of discourse analysis techniques as well as image and audio analysis methods. The proposed system was developed in partnership with the free-to-air Brazilian TV channel Rede Minas in an attempt to provide TV researchers with computational tools to assist their studies about this media universe. The system is based on the Matterhorn framework for managing video libraries, combining: (1) discourse analysis techniques for describing and indexing the videos, by considering aspects, such as, definitions of the subject of analysis, the nature of the speaker and the corpus of data resulting from the discourse; (2) a state of the art decoder software for large vocabulary continuous speech recognition, called Julius; (3) image and frequency domain techniques to compute visual signatures for the video recordings, containing color, shape and texture information; and (4) hashing and k-d tree methods for data indexing. The capabilities of SAPTE were successfully validated, as demonstrated by our experimental results, indicating that SAPTE is a promising computational tool for TV researchers.

A unified approach to content-based indexing and retrieval of digital videos from television archives

This work addresses the development of a unified approach to content-based indexing and retrieval of digital videos fromtelevision archives. The proposed approach has been designed to deal with arbitrary television genres, making it suitablefor various applications. To achieve this goal, the main steps of a content-based video retrieval system are addressed in thiswork, namely: video segmentation, key-frame extraction, content-based video indexing and the video retrieval operation itself.Video segmentation is addressed as a typical TV broadcast structuring problem, which consists in automatically determiningthe boundaries of each broadcasted program (like movies, news, among others) and inter-program (for instance, commercials).Specifically, to segment the videos, Electronic Program Guide (EPG) metadata is combined with the detection of two specialcues, namely, audio cuts (silence) and dark monochrome frames. On the other hand, a color histogram-based approach performskey-frame extraction. Video indexing and retrieval are accomplished by using hashing and k-d tree methods, while visualsignatures containing color, shape and texture information are estimated for the key-frames, by using image and frequencydomain techniques. Experimental results with the dataset of a multimedia information system especially developed for managingtelevision broadcast archives demonstrate that our approach works efficiently, retrieving videos in 0.16 seconds on average andachieving recall, precision and F1 measure values, as high as 0.76, 0.97 and 0.86 respectively.