Browsing by Author "Liu, TL"

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Direct energy minimization for super-resolution on nonlinear manifolds
(2006)
Chang, TL
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Liu, TL
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Chuang, JH
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資訊工程學系
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Department of Computer Science
We address the problem of single image super-resolution by exploring the manifold properties. Given a set of low resolution image patches and their corresponding high resolution patches, we assume they respectively reside on two non-linear manifolds that have similar locally-linear structure. This manifold correlation can be realized by a three-layer Markov network that connects performing super-resolution with energy minimization. The main advantage of our approach is that by working directly with the network model, there is no need to actually construct the mappings for the underlying manifolds. To achieve such efficiency, we establish an energy minimization model for the network that directly accounts for the expected property entailed by the manifold assumption. The resulting energy function has two nice properties for super-resolution. First, the function is convex so that the optimization can be efficiently done. Second, it can be shown to be an upper bound of the reconstruction error by our algorithm. Thus, minimizing the energy function automatically guarantees a lower reconstruction error- an important characteristic for promising stable super-resolution results.
Structures and properties of the SiNC films on Si wafer at different deposition stages
(2001-11-01)
Wu, JY
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Kuo, CT
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Liu, TL
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材料科學與工程學系
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Department of Materials Science and Engineering
The films were deposited on Si wafer by a microwave plasma chemical vapor deposition (MPCVD) system with CH4, N-2, up to 8.3 vol.% HZ and additional Si chips as the sources. The films were examined at different deposition times to explore different growth stages of deposition. Examination indicated the deposition can be roughly divided up to three stages, depending on deposition time and based on their structure and property. In the early deposition stages, the films consist of two layers, i.e. Si-oxide and SiNC layers. The SiNC layer consists essentially of nano-crystals embedded in ternary SiNC amorphous matrix with crystal structure close to SiC. In contrast, in the later stage, the films are further covered by a layer of the binary SiN crystalline phases with crystal structures much closer to alpha -Si3N4 than beta -Si3N4 and tetragonal Si3N4 type structures. The band gaps, as revealed by CL (cathodoluminescence) spectra, are similar to3.88 eV (320 nm) for SiN layer and similar to2.82 eV (440 nm) for SiNC layer. Depending on the deposition conditions, the growth competitions among SiC, Si-N and SiNC crystalline phases may result in different morphologies, compositions and properties of the films. (C) 2001 Elsevier Science B.V All rights reserved.