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Efficient video retrieval using complex sketches and exploration based on semantic descriptors
Blažek, Adam ; Lokoč, Jakub (advisor) ; Mráz, František (referee)
This thesis focuses on novel video retrieval scenarios. More particularly, we aim at the Known-item Search scenario wherein users search for a short video segment known either visually or by a textual description. The scenario assumes that there is no ideal query example available. Our former known- item search tool relying on color feature signatures is extended with major enhancements. Namely, we introduce a multi-modal sketching tool, the exploration of video content with semantic descriptors derived from deep convolutional networks, new browsing/visualization methods and two orthogonal approaches for textual search. The proposed approaches are embodied in our video retrieval tool Enhanced Sketch-based Video Browser (ESBVB). To evaluate ESBVB performance, we participated in international competitions comparing our tool with the state-of-the-art approaches. Repeatedly, our tool outperformed the other methods. Furthermore, we show in our user study that even novice users are able to effectively employ ESBVB capabilities to search and browse known video clips. Powered by TCPDF (www.tcpdf.org)
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Vektorový screencast
Rozsíval, Šimon ; Děcký, Martin (advisor) ; Lokoč, Jakub (referee)
The goal of this bachelor thesis is to create a software for recording and playback of educational videos for Khanova škola (Czech clone of Khan Academy). Contrary to common videos the visual data is not stored as a sequence of bitmaps, but as vectors. This allows to reduce the data bandwidth and playback sharp images in any target resolution. The player and also the tool for recording the videos runs in a web browser. The thesis also focuses on designing and implementing a suitable file format for storing the visual and audio data and implementing the software according to the client/server paradigm. Powered by TCPDF (www.tcpdf.org)
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The Impact of Image Resolution on the Precision of Content-based Retrieval
Navrátil, Lukáš ; Lokoč, Jakub (advisor) ; Skopal, Tomáš (referee)
This thesis is focused on comparing methods for similarity image retrieval. Common techniques and testing sets are introduced. The testing sets are there to measure the accuracy of the searching systems based on similarity image retrieval. Measurements are done on those models which are implemented on the basis of presented techniques. These measurements examine their results depending on the input data, used components and parameters settings, especially the impact of image resolution on the retrieval precision is examined. These results are analysed and the models are compared. Powered by TCPDF (www.tcpdf.org)
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A SQL front-end for the Bobox system
Klimperová, Lucie ; Bednárek, David (advisor) ; Lokoč, Jakub (referee)
The goal of this thesis is to design and implement a SQL frontend for Bobox framework which is being developed by Department of software engineering MFF UK. The development of the Bobox framework is motivated by the effort to simplify writing parallel software. The Bobox framework is one of many system implementations for processing stream data and provides runtime environment for evaluating execution plans in the parallel environment. This thesis deals with implementation of a frontend for this framework. The input is a query in SQL language and information about database structure. Frontend will perform syn- tactic and semantic analysis and then translate the input query into intermediate code. The output of this frontend is the intermediate code in the form of relatio- nal algebra written as XML and is used as the input for the following optimizing backend.
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Presentation Layer For Multimedia Exploration In Multimedia Collections
Macík, Miroslav ; Lokoč, Jakub (advisor) ; Hoksza, David (referee)
Multimedia exploration is addressing the issue of searching within multimedia collections where the data is not annotated, the user is not able to formulate the text query, does not have any example data or wants to get quickly acquainted with the features of the collection. Part of the exploration is also the presentation of the results which is the main contribution of this thesis. The relations between the pictures in the exploration results are transformed into a graph which is visualised through a particle physics model. To visualize a large number of pictures, it is necessary to optimize the calculation. This thesis describes the optimization of both the basic algorithms and their adaptations for the need of multimedia exploration. The calculation layout is available in 2D and 3D space. Powered by TCPDF (www.tcpdf.org)
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A fingerpring database
Kubát, Jaroslav ; Babka, Martin (advisor) ; Lokoč, Jakub (referee)
The main goal of this thesis is to provide full description of an implementation of an application that is supposed to be a complex dactyloscopic database tool. The text is divided into parts according to the functional blocks of the application. The parts are namely processing of input fingerprint, the minutiae point analysis, the description of minutiae representation, the database and index structure described with its operations. Usually we describe multiple algorithms for a single task. In this case we provide their comparison. At the end of this thesis, there is a user manual describing the main usage scenarios. Powered by TCPDF (www.tcpdf.org)
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Multi-model Approach For Effective Multimedia Exploration
Grošup, Tomáš ; Lokoč, Jakub (advisor)
This work is focusing on exploration of multimedia collections. It describes the problematic of exploration and proposes new approaches to it, two based on the data structure M-Index and two utilizing multiple similarity models at once. Those approaches were compared using an extensive user study. Part of this work is also devoted to analysis of a new exploration system, design of its architecture, system implementation and its deployment. This exploration system was used in several applications, which are also shown and described in this thesis.
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Multi-model Approach For Effective Multimedia Exploration
Grošup, Tomáš ; Lokoč, Jakub (advisor) ; Somol, Petr (referee)
This work is focusing on exploration of multimedia collections. It describes the problematic of exploration and proposes new approaches to it, two based on the data structure M-Index and two utilizing multiple similarity models at once. Those approaches were compared using an extensive user study. Part of this work is also devoted to analysis of a new exploration system, design of its architecture, system implementation and its deployment. This exploration system was used in several applications, which are also shown and described in this thesis.
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Using Metric Indexes For Effective and Efficient Multimedia Exploration
Čech, Přemysl ; Lokoč, Jakub (advisor) ; Skopal, Tomáš (referee)
The exponential growth of multimedia data challenges effectiveness and efficiency of the state-of-the- art retrieval techniques. In this thesis, we focus on browsing of large datasets using exploration approaches where query cannot be particularly expressed or where the need of some general notion of the dataset is required. More specifically, we study exploration scenarios utilizing the metric access method PM-Tree which natively creates a hierarchy of nested metric regions. We enhance the PM- Tree for the exploration purposes and define different traversing and querying strategies. Further, we investigate range multi-query (range query defined by multiple objects) approaches. We propose new effective and efficient cut-region range query and compare the new query with other approaches for efficient multi-query processing. Finally, we implemented all new methods and strategies for the PM- Tree into multimedia exploration framework and tested browsing algorithms on a game-like demo application.
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Signature-based video browser
Blažek, Adam ; Lokoč, Jakub (advisor) ; Kruliš, Martin (referee)
In this thesis, we present an effective yet efficient approach for Known-Item Search in video data. The approach utilizes so called feature signatures - simple and flexible visual descriptors based on color distribution. The feature signatures enable to efficiently represent video key-frames and at the same time allow users to intuitively draw simple colored sketches of the searched scenes. In the thesis, we describe in detail a novel video retrieval model and also discuss and carefully optimize it's parameters. To achieve high efficiency, we expose several indexing techniques suitable for the model and empirically evaluate their performance in the experiments. The described model is implemented in C# programming language with simple and intuitive user interface enabling users to~ interactively browse up to tens of hours of video. Powered by TCPDF (www.tcpdf.org)
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