This letter studies the performance of various image representation schemes used for image search problems for the purpose of geographic image retrieval from satellite imagery. We compare the most widely adopted method of the bag-of-words (BoW) approach with the more recently introduced vector of locally aggregated descriptors (VLAD) and its more compact binary version product quantized VLAD (VLAD-PQ). We show with the experiments on a publicly available 21-class land-use/land-cover data set that the VLAD-based representation outperforms BoW at the cost of increased query time, but the more compact VLAD-PQ representation achieves very similar performance as VLAD without the increased time requirement.Index Terms-Geographic information systems, image representation, image retrieval.

Content Based Copy Detection (CBCD) emerges as a viable choice against active detection methodology ofwatermarking. The very first reason is that the media already under circulation cannot be marked and secondly, CBCD inherently can endure various severe attacks, which watermarking cannot. Although in general, media content is handled independently as visual and audio in this work both information sources are utilized in a unified framework, in which coarse representation of fundamental features are employed. From the copy detection perspective, number of attacks on audio content is limited with respect to visual case. Therefore audio, if present, is an indispensable part of a robust video copy detection system. In this study, the validity of this statement is presented through various experiments on a large data set.

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Information theoretic tools lead to the design and analysis of new blind data hiding methods. A novel quantizationbased blind method, which uses trellis coded quantization, is proposed in this manuscript. The redundancy in initial state selection during trellis coded quantization is exploited to hide information as the index of this initial state. This index is recovered at the receiver by Viterbi decoding after comparison with all initial states. The performance of the proposed method is compared against other well-known approaches via simulations and promising results are obtained. Based on these results, the proposed method can be preferred in certain applications with high distortion attacks.