Listen, Look, and Gotcha: Instant Video Search with Mobile Phones by Layered Audio-Video Indexing *

ABSTRACT Mobile video is quickly becoming a mass consumer phenomenon. More and more people are using their smartphones to search and browse video content while on the move. In this paper, we have developed an innovative instant mobile video search system through which users can discover videos by simply pointing their phones at a screen to capture a very few seconds of what they are watching. The system is able to index large-scale video data using a new layered audio-video indexing approach in the cloud, as well as extract light-weight joint audio-video signatures in real time and perform progressive search on mobile devices. Unlike most existing mobile video search applications that simply send the original video query to the cloud, the proposed mobile system is one of the first attempts at instant and progressive video search leveraging the light-weight computing capacity of mobile devices. The system is characterized by four unique properties: 1) a joint audio-video signature to deal with the large aural and visual variances associated with the query video captured by the mobile phone, 2) layered audio-video indexing to holistically exploit the complementary nature of audio and video signals, 3) light-weight fingerprinting to comply with mobile processing capacity, and 4) a progressive query process to significantly reduce computational costs and improve the user experience-the search process can stop anytime once a confident result is achieved. We have collected 1,400 query videos captured by 25 mobile users from a dataset of 600 hours of video. The experiments show that our system outperforms state-of-the-art methods by achieving 90.79% precision when the query video is less than 10 seconds and 70.07% even when the query video is less than 5 seconds. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from [email protected]. The search process can stop anytime once a confident search result is achieved. Thus, the user does not need to wait for a fixed time lag. The proposed system is characterized by its unique features such as layered audio-video indexing, as well as instant and progressive search. Categories and Subject Descriptor

combining multimodal external resources for event-based news video retrieval and question answering

Ph.DDOCTOR OF PHILOSOPH

Fine-grained Incident Video Retrieval with Video Similarity Learning.

PhD ThesesIn this thesis, we address the problem of Fine-grained Incident Video Retrieval (FIVR) using video similarity learning methods. FIVR is a video retrieval task that aims to retrieve all videos that depict the same incident given a query video { related video retrieval tasks adopt either very narrow or very broad scopes, considering only nearduplicate or same event videos. To formulate the case of same incident videos, we de ne three video associations taking into account the spatio-temporal spans captured by video pairs. To cover the benchmarking needs of FIVR, we construct a large-scale dataset, called FIVR-200K, consisting of 225,960 YouTube videos from major news events crawled from Wikipedia. The dataset contains four annotation labels according to FIVR de nitions; hence, it can simulate several retrieval scenarios with the same video corpus. To address FIVR, we propose two video-level approaches leveraging features extracted from intermediate layers of Convolutional Neural Networks (CNN). The rst is an unsupervised method that relies on a modi ed Bag-of-Word scheme, which generates video representations from the aggregation of the frame descriptors based on learned visual codebooks. The second is a supervised method based on Deep Metric Learning, which learns an embedding function that maps videos in a feature space where relevant video pairs are closer than the irrelevant ones. However, videolevel approaches generate global video representations, losing all spatial and temporal relations between compared videos. Therefore, we propose a video similarity learning approach that captures ne-grained relations between videos for accurate similarity calculation. We train a CNN architecture to compute video-to-video similarity from re ned frame-to-frame similarity matrices derived from a pairwise region-level similarity function. The proposed approaches have been extensively evaluated on FIVR- 200K and other large-scale datasets, demonstrating their superiority over other video retrieval methods and highlighting the challenging aspect of the FIVR problem

Robust short clip representation and fast search through large video collections

Master'sMASTER OF ENGINEERIN

HIERARCHICAL LEARNING OF DISCRIMINATIVE FEATURES AND CLASSIFIERS FOR LARGE-SCALE VISUAL RECOGNITION

Enabling computers to recognize objects present in images has been a long standing but tremendously challenging problem in the field of computer vision for decades. Beyond the difficulties resulting from huge appearance variations, large-scale visual recognition poses unprecedented challenges when the number of visual categories being considered becomes thousands, and the amount of images increases to millions. This dissertation contributes to addressing a number of the challenging issues in large-scale visual recognition. First, we develop an automatic image-text alignment method to collect massive amounts of labeled images from the Web for training visual concept classifiers. Specif- ically, we first crawl a large number of cross-media Web pages containing Web images and their auxiliary texts, and then segment them into a collection of image-text pairs. We then show that near-duplicate image clustering according to visual similarity can significantly reduce the uncertainty on the relatedness of Web images’ semantics to their auxiliary text terms or phrases. Finally, we empirically demonstrate that ran- dom walk over a newly proposed phrase correlation network can help to achieve more precise image-text alignment by refining the relevance scores between Web images and their auxiliary text terms. Second, we propose a visual tree model to reduce the computational complexity of a large-scale visual recognition system by hierarchically organizing and learning the classifiers for a large number of visual categories in a tree structure. Compared to previous tree models, such as the label tree, our visual tree model does not require training a huge amount of classifiers in advance which is computationally expensive. However, we experimentally show that the proposed visual tree achieves results that are comparable or even better to other tree models in terms of recognition accuracy and efficiency. Third, we present a joint dictionary learning (JDL) algorithm which exploits the inter-category visual correlations to learn more discriminative dictionaries for image content representation. Given a group of visually correlated categories, JDL simul- taneously learns one common dictionary and multiple category-specific dictionaries to explicitly separate the shared visual atoms from the category-specific ones. We accordingly develop three classification schemes to make full use of the dictionaries learned by JDL for visual content representation in the task of image categoriza- tion. Experiments on two image data sets which respectively contain 17 and 1,000 categories demonstrate the effectiveness of the proposed algorithm. In the last part of the dissertation, we develop a novel data-driven algorithm to quantitatively characterize the semantic gaps of different visual concepts for learning complexity estimation and inference model selection. The semantic gaps are estimated directly in the visual feature space since the visual feature space is the common space for concept classifier training and automatic concept detection. We show that the quantitative characterization of the semantic gaps helps to automatically select more effective inference models for classifier training, which further improves the recognition accuracy rates