Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"transform coding"”.
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Nonlinear transform coding with lossless polar coordinates
In conventional transform coding, the importance of preserving desirable quantization partition cell shapes prevents one from considering the use of a nonlinear change of variables. If no linear transformation of a given source would yield independent components, this means having to encode it at a …
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Audio compression via nonlinear transform coding and stochastic binary activation
… others, that have surpassed the longstanding MP3 coding format. However most of the methods are laboriously engineered using psychoacoustic modeling, and some of them are proprietary and only see limited use. This thesis, inspired by recent major breakthroughs in lossy image compression via …
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Approximate signal reconstruction from partial information
It is known that transform techniques do not represent an optimal way in which to code a signal in terms of theoretical rate distortion bounds. A signal may be coded more efficiently if side information is included with the signal during transmission. This side information can then be used to …
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Investigation of Different Video Compression Schemes Using Neural Networks
… the development of various techniques including transform coding, vector quantization and neural networks. this thesis neural network based methods are investigated to achieve good compression ratios while maintaining the image quality. Parts of this investigation include motion detection, and …
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Hardware Implementation of a Novel Image Compression Algorithm
… have been developed in the past, including transform coding, vector quantization and neural networks. In this thesis, a novel adaptive compression technique is introduced based on adaptive rather than fixed transforms for image compression. The proposed technique is similar to Neural Network …
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Image Compression Using Cascaded Neural Networks
… techniques developed for this purpose include transform coding, vector quantization and neural networks. In this thesis, a new neural network method is used to achieve image compression. This work extends the use of 2-layer neural networks to a combination of cascaded networks with one node in …
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Astronomical image manipulation in the transform domain
… bandwidth. Among many image compression schemes, transform coding is a widely used coding method. Traditionally, processing a compressed image requires decompression first. Following manipulations, the processed image is compressed again for storage. To reduce the computational complexity and …
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Source coded image data in the presence of channel errors
… the tendency is towards trans-form source coding of the image data. This method of source coding has reached a stage where very high reductions in the number of bits representing the data can be made while still preserving image fidelity. The point has thus been reached where channel errors …
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Signal compression and reconstruction using multiple bases representation
… at low data rates involves, in general, the encoding of the source for maximum data compression at the transmitter end, and the reconstruction using the received information and all the available a priori or side information at the receiver end. In this thesis, we propose an adaptive signal …
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Group testing for image compression
… testing is a generalization of the zerotree coding method widely used in wavelet-based image compression. We also show the equivalence of elementary Golomb codes and the binary splitting procedure used in Hwang's generalized group testing method. Next, we present new image coding techniques …
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Functional quantization
… point. Are performance gains possible if source coding accounts for the user's function? How about when the encoders cannot themselves compute the function? We introduce the notion of functional quantization and use the tools of high-resolution analysis to get to the bottom of this question. …
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Image data compression using multiple bases representation
… has been a lot of research into the efficient coding of gray scale images. Vector quantization (Va) methods have been successfully applied to the efficient coding of images. These methods, however, are computationally intensive. Full search Multiple Bases Representation (MBR) is similar to Va …
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Video coding with adaptive vector quantization and rate distortion optimization
… quantization is applied in <br>the wavelet transform domain. The organization of the wavelet coefficients is then made more efficient using adaptive partition techniques. Moreover, the main adaptability mechanism of adaptive vector quantization, the so-called codebook update, is studied. …
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Image Compression Using Balanced Multiwavelets
The success of any transform coding technique depends on how well the basis functions represent the signal features. The discrete wavelet transform (DWT) performs a multiresolution analysis of a signal; this enables an efficient representation of smooth and detailed signal regions. Furthermore, …
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Some Notes on Compressive Sensing
We are living in a world in which the growth rate of the data generated every year is almost exponential. A significant problem is how we can store this amount of data. Compressive sensing is giving us a clue about how we can reconstruct images and signals from frequency data, by having less …
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Subspace methods for portfolio design
… video compression applications, Discrete Cosine Transform (DCT) has been successfully employed in transform coding where Karhunen-Loeve Transform (KLT) is the optimum block transform. In this dissertation, a signal processing framework to design investment portfolios is proposed. Portfolio theory …
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Structured vector quantizers in image coding
… to retain the high-frequency coefficients in transform coding, two methods are suggested. One is developed for moderate to high rate data compression while the other is effective for low to moderate data rate. In the first part of this thesis, a residual VQ using a low rate optimal VQ in the …