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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.
31

Efektivní nástroj pro kompresi obrazu v jazyce Java / JAVA-based effective implementation of an image compression tool

Průša, Zdeněk January 2008 (has links)
This diploma thesis deals with digital image lossy compression. Lossy compression in general inserts some kind of distorsion to the resulting image. The distorsion should not be interupting or even noticable in the better case. For image analysis there is used process called transformation and for choosing relevant coefficients process called coding. Evaluation of image quallity can be done by objective or subjective method. There is encoder introduced and realized in this work. Encoder utilizes two-dimension wavelet transform and SPIHT algortihm for coefficient coding. It was made use of accelerated method of wavelet transform computation by lifting scheme. Coder can proccess color information of images using modificated original SPIHT algorithm. For implementation the JAVA programming language was employed. The object-oriented design principes was made use of and thus the program is easy to extended. At demonstaration pictures there are shown effectiveness and characteristic way of distorsion of the proposed coder at high compression rates.
32

Využití pokročilých objektivních kritérií hodnocení při kompresi obrazu / Advanced objective measurement criteria applied to image compression

Šimek, Josef January 2010 (has links)
This diploma thesis deals with the problem of using an objective quality assessment methods in image data compression. Lossy compression always introduces some kind of distortion into the processed data causing degradation in the quality of the image. The intensity of this distortion can be measured using subjective or objective methods. To be able to optimize compression algorithms the objective criteria are used. In this work the SSIM index as a useful tool for describing the quality of compressed images has been presented. Lossy compression scheme is realized using the wavelet transform and SPIHT algorithm. The modification of this algorithm using partitioning of the wavelet coefficients into the separate tree-preserving blocks followed by independent coding, which is especially suitable for parallel processing, was implemented. For the given compression ratio the traditional problem is being solved – how to allocate available bits among the spatial blocks to achieve the highest possible image quality. The possible approaches to achieve this solution were discussed. As a result, some methods for bit allocation based on MSSIM index were proposed. To test the effectivity of these methods the MATLAB environment was used.
33

Vkládání vodoznaků do 3D modelů / Watermarking 3D Models

Honzátková, Tereza January 2016 (has links)
Goals of this work are to summarize the process and existing methods of 3D models watermarking, to choose relevant methods for embedding/extraction of a watermark to/from 3D models. The final solution is based on Spectral Mesh Compression technique. This method is robust, imperceptible and informed. The embedded watermark is detectable and robust against geometrical transformations, added random noise, mesh smoothing and simplification, compression and cropping.  The realized tool allows a user to embedding watermark into the mesh, modify the mesh and extraction of a watermark from mesh. Testing was conducted on a set of 5 models differing in size, shape and density of points. The resulting tool inserts a watermark composed of four characters that can detect both undamaged models and the models affected. Among the attacks against which the watermark is robust, include transformations, rotation, scale, adaptive random noise, and combination of this.
34

Akcelerace kompresního algoritmu LZ4 v FPGA / Acceleration of LZ4 Compression Algorithm in FPGA

Marton, Dominik January 2017 (has links)
This project describes the implementation of an LZ4 compression algorithm in a C/C++-like language, that can be used to generate VHDL programs for FPGA integrated circuits embedded in accelerated network interface controllers (NICs). Based on the algorithm specification, software versions of LZ4 compressor and decompressor are implemented, which are then transformed into a synthesizable language, that is then used to generate fully functional VHDL code for both components. Execution time and compression ratio of all implementations are then compared. The project also serves as a demonstration of usability and influence of high-level synthesis and high-level approach to design and implementation of hardware applications known from common programming languages.
35

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

Bradáč, Václav January 2017 (has links)
This work deals with image compression using wavelet transformation. At the beginning , you can find theoretical information about the best known techniques used for image compression , a thorough description of wavelet transormation and the EBCOT algorithm. A significant part of the work is devoted to the library's own implementation . Another chapter of the diploma thesis deals with the comparison and evaluation of the achieved results of the processed library with the JPEG2000 format
36

Zachytávání a komprese videa na vestavěných zařízeních / Video Capture and Compression on Embedded Devices

Dušek, Oto January 2020 (has links)
Industrial cameras are often used in conjunction with the application of machine learning. However, these cameras produce large bitrate and it needs to be reduced when processing video further away from the camera. This thesis tries to solve the problem by design of system suitable for grabbing video from industrial cameras, its compression and distribution to machine learning application. The thesis describes technologies applicable to the development of the multimedia application. For example frameworks FFmpeg and GStreamer were used implementation of the system.
37

Software pro převzetí kontroly nad počítačem / Software for assuming control over the computer

Kostelník, Jan January 2008 (has links)
The introduction of this Master’s thesis describes a historical and technological evolution of the terminal application, including its advantages and disadvantages. In the following part, a general description of the services and their understanding are mentioned. The benefits and general advantages of the terminal services are described. For the each type of the terminal service, all the functions, options, exact advantages and disadvantages are described. Consequently, the study of the suitability of the compression is presented. On the demo application, the impact of an excessive (voluntary) loss of information is demonstrated. In the next part, the thesis deals with the most frequently used remote-control applications. The tests and comparisons are made as well. The fifth chapter is the fundamental part of this work. The design approach of the workbench is presented there. Consequently, the design approach and system implementation intended for the supervision and control is described. This system makes the user possible to observe other user’s activities and also to control their workstations. The supervising user can also access their drives and other memory devices, which are located in the monitored workstation. The communication is compressed and encrypted. The symmetric and asymmetric encryption algorithms are used there. In the following part, there are two supplementary applications mentioned – application for the key generating and network file manager. In the end of my work, the results of the performance test and also the design of other improvements are presented.
38

Měření zkreslení signálu EKG / ECG Signal Distortion Measures

Požár, Pavel January 2012 (has links)
This master's thesis deals with electrocardiogram and its distortion, which causes errors, due to which a doctor can make a wrong diagnosis. In the theoretical part electrocardiogram is briefly described, further theory of wavelet transform, introduction to the signal compression and some information about ECG delineation. Methods used for the signal evaluation and therefore determination of the distortion size are described in the main theoretical part. This thesis contains known methods and also a method of own design based on the ECG delineation. Some of the described methods are checked in the practical part. These methods are tested for two different compression algorithms, which cause various distortion. In the final part distortion was tested on the influence on setting the wrong diagnosis.
39

Digitální ekvalizér s kompresorem dynamiky / Digital equalizer with dynamic range compression

Šafer, Radim January 2012 (has links)
The aim of the thesis is to create a digital equalizer with dynamic range compression. The master's thesis is focused on the comparison of functions and parameters of individual digital processors which are given entirely for sound signals processing. It contains the detailed analysis of singular blocks used for signal processing in the circuit AD1953 and possibilities of control over programmable parametres of those blocks by a user. This thesis also contains a comparasion of the chosen A/D converters together with a description of the UDA1361TS circuit. A designed functional diagram of the final device is introduced as well. Thereafter possibilities of controling the individual blocks in the signal processor are mentioned. The final design of the digital equalizer is also introduced along with a description of software essential to a successful control over the processing of the signal in the AD1953 circuit. This thesis also describes a construction of the digital equalizer and involves results of the chosen measurements.
40

Komprese obrazu v interaktivních aplikacích digitálního televizního vysílání / Image compression in interactive applications in digital video broadcasting

Bodeček, Kamil January 2008 (has links)
Compressed images are used very frequently in interactive applications in digital video broadcasting. New methods increasing efficiency of the image transmission in digital video broadcasting networks are proposed. Adaptive spatial filtering methods have been proposed for enhancement of the visual perception of the compressed images. New optimalization method is based on application of the filtering algorithms on more compressed images (data size are reduced). Visual quality enhancement is processed in interactive application. Further, new compression methods JPEG2000 and H.264 for image compression have been analysed. Novel compound image compression method for standard and high spatial television resolution is proposed in the thesis.

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