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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Alternativní JPEG kodér/dekodér / An alternative JPEG coder/decoder

Jirák, Jakub January 2017 (has links)
The JPEG codec is currently the most widely used image format. This work deals with the design and implementation of an alternative JPEG codec using proximal algorithms in combination with the fixation of points from the original image to suppression of artifacts created in common JPEG coding. To solve the problem, the prox_TV and then the Douglas-Rachford algorithm were used, for which special functions using l_1-norm for image reconstruction were derived. The results of the proposed solution are very good because they can effectively suppress the artefacts created and the result corresponds to the image with a higher set qualitative factor. The proposed method achieves very good results for both simple images and photos, but in the case of large images (1024 × 1024 px) and larger, a large amount of computing time is required, so the method is more suitable for smaller images.
122

Zpracování digitální fotografie / Digital Photo Processing

Zdražil, Vít Unknown Date (has links)
This document focuses on processing of RAW image data from digital cameras. In first section is described principle of image capturing by digital camera, common way of image processing in the device and what the RAW format is, its pros and cons. In the next section is described existing demosaicing methods, methods for additional processing of RAW image data and there is analyzed specific RAW format, Canon's CR2, including structure and guide for its conversion. Next sections contains proposal of the new improved demosaicing method and method for suppressing digital noise. On this basis a library for basic CR2 files processing was implemented. There is comparison of methods for processing RAW image data with this library in the next section. In the conclusion there is summary of finished work and there is also mentioned outline of future work.
123

PCA and JPEG2000-based Lossy Compression for Hyperspectral Imagery

Zhu, Wei 30 April 2011 (has links)
This dissertation develops several new algorithms to solve existing problems in practical application of the previously developed PCA+JPEG2000, which has shown superior rate-distortion performance in hyperspectral image compression. In addition, a new scheme is proposed to facilitate multi-temporal hyperspectral image compression. Specifically, the uniqueness in each algorithm is described as follows. 1. An empirical piecewise linear equation is proposed to estimate the optimal number of major principal components (PCs) used in SubPCA+JPEG2000 for AVIRIS data. Sensor-specific equations are presented with excellent fitting performance for AVIRIS, HYDICE, and HyMap data. As a conclusion, a general guideline is provided for finding sensor-specific piecewise linear equations. 2. An anomaly-removal-based hyperspectral image compression algorithm is proposed. It preserves anomalous pixels in a lossless manner, and yields the same or even improved rate-distortion performance. It is particularly useful to SubPCA+JPEG2000 when compressing data with anomalies that may reside in minor PCs. 3. A segmented PCA-based PCA+JPEG2000 compression algorithm is developed, which spectrally partitions an image based on its spectral correlation coefficients. This compression scheme greatly improves the rate-distortion performance of PCA+JPEG2000 when the spatial size of the data is relatively smaller than its spectral size, especially at low bitrates. A sensor-specific partition method is also developed for fast processing with suboptimal performance. 4. A joint multi-temporal image compression scheme is proposed. The algorithm preserves change information in a lossless fashion during the compression. It can yield perfect change detection with slightly degraded rate-distortion performance.
124

Komprese obrazu pomocí vlnkové transformace / Image Compression Using the Wavelet Transform

Urbánek, Pavel January 2013 (has links)
This thesis is focused on subject of image compression using wavelet transform. The first part of this document provides reader with information about image compression, presents well known contemporary algorithms and looks into details of wavelet compression and following encoding schemes. Both JPEG and JPEG 2000 standards are introduced. Second part of this document analyzes and describes implementation of image compression tool including inovations and optimalizations. The third part is dedicated to comparison and evaluation of achievements.
125

Komprese videa v obvodu FPGA / Implementation of video compression into FPGA chip

Tomko, Jakub January 2014 (has links)
This thesis is focused on the compression algorithm's analysis of MJPEG format and its implementation in FPGA chip. Three additional video bitstream reduction methods have been evaluated for real-time low latency applications of MJPEG format. These methods are noise filtering, inter-frame encoding and lowering video's quality. Based on this analysis, a MJPEG codec has been designed for implementation into FPGA chip XC6SLX45, from Spartan-6 family.
126

Reducing Energy Consumption Through Image Compression / Reducera energiförbrukning genom bildkompression

Ferdeen, Mats January 2016 (has links)
The energy consumption to make the off-chip memory writing and readings are aknown problem. In the image processing field structure from motion simpler compressiontechniques could be used to save energy. A balance between the detected features suchas corners, edges, etc., and the degree of compression becomes a big issue to investigate.In this thesis a deeper study of this balance are performed. A number of more advancedcompression algorithms for processing of still images such as JPEG is used for comparisonwith a selected number of simpler compression algorithms. The simpler algorithms canbe divided into two categories: individual block-wise compression of each image andcompression with respect to all pixels in each image. In this study the image sequences arein grayscale and provided from an earlier study about rolling shutters. Synthetic data setsfrom a further study about optical flow is also included to see how reliable the other datasets are. / Energikonsumtionen för att skriva och läsa till off-chip minne är ett känt problem. Inombildbehandlingsområdet struktur från rörelse kan enklare kompressionstekniker användasför att spara energi. En avvägning mellan detekterade features såsom hörn, kanter, etc.och grad av kompression blir då en fråga att utreda. I detta examensarbete har en djuparestudie av denna avvägning utförts. Ett antal mer avancerade kompressionsalgoritmer förbearbetning av stillbilder som tex. JPEG används för jämförelse med ett antal utvaldaenklare kompressionsalgoritmer. De enklare algoritmerna kan delas in i två kategorier:individuell blockvis kompression av vardera bilden och kompression med hänsyn tillsamtliga pixlar i vardera bilden. I studien är bildsekvenserna i gråskala och tillhandahållnafrån en tidigare studie om rullande slutare. Syntetiska data set från ytterligare en studie om’optical flow’ ingår även för att se hur pass tillförlitliga de andra dataseten är.
127

Digitální knihovna / Digital Library

Krbeček, Daniel January 2008 (has links)
The thesis contains basic information about image documents digitalization. A brief list of common used standards in Czech republic is shown. The standards can be used in description of digitalized documents by institutions such as libraries, scientific departments and universities. The thesis specifically solves the dilemma of the preservation and the accessing of B.P.Molls large map collection stored in Moravian Library in Brno city. It analyses step by step the characteristics of the saved documents, style of their interlacing and data representation. In terms of deposition and manipulation it comes with description list of open-source digital libraries and it chooses the Fedora repository. It solves methods of object-model implementation while using this digital library. The functional parts are web presentation of the mentioned map collection and an effectiveness test showing large-scale maps using the flash Zoomify browser. Web presentation uses the repository services as often as possible, and thus allows searching and searching through the bibliographic records of the presented documents. The end of the thesis sums up the obtained results and presents the incoming development course of presentation and popularization of the map collection.
128

Produkce digitálních obrazových dat a jejich kontrola / Digital Images Production and Quality Control

Vychodil, Bedřich January 2013 (has links)
(EN) This dissertation provides a broad understanding of fundamental terminology and an inside view of the digitization workflow and quality control processes. The main foci are on quality assurance during and outside the digitization processes and identification of the most suitable format for access, long term preservation, rendering and reformatting issues. An analysis of selected digitization centers is also included. An application called DIFFER (Determinator of Image File Format propERties) and subsequently The Image Data Validator - DIFFER has been developed using results from previously conducted research. The application utilizes new methods and technologies to help accelerate the whole processing and quality control. The goal was to develop a quality control application for a select group of relevant still image file formats capable of performing identification, characterization, validation and visual/mathematical comparison integrated into an operational digital preservation framework. This application comes with a well-structured graphic user interface, which helps the end user to understand the relationships between various file format properties, detect visual and non visual errors and simplify decision-making. Additional comprehensive annexes, describing the most crucial still image...
129

Knihovna pro efektivní záznam videa v 3D aplikaci / Library for Efficient Video Capture in 3D Application

Pospíšil, Petr January 2012 (has links)
This thesis deals with library for recording video in the background of 3D application. A library is designed to work under the Microsoft Windows and Linux operation systems.  It records image and also sound. Image recording is supported in OpenGL, Direct3D9, Direct3D10 and Direct3D11. To reduce video data size, library supports image compression using MJPG codec. Audio is recorded by WaveForm audio, Windows Core Audio or ALSA. Recorded sound is for whole operation system. A library is able to record up to two audio streams to accommodate possible microphone input. It can mix audio data together if needed. Output data are then written into AVI file. It is possible to write own text information as overlay that is rendered as part of application screen output.

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