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- Title
- Performance modeling of liquid crystal phase diffraction gratings suitable for HDTV projection systems.
- Creator
- Wu, Kaiyu., Florida Atlantic University, Glenn, William E., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Because of the inherent inefficiency associated with polarization-rotation liquid crystal light valves in an high intensity environment, this paper discusses the applicability and performance of these valves operated as phase diffraction gratings in HDTV projection systems. A numerical method for evaluating performance and optimizing design parameters is presented. The resulting model is used to consider design improvement to increase the modulation efficiency and to adapt the projector to...
Show moreBecause of the inherent inefficiency associated with polarization-rotation liquid crystal light valves in an high intensity environment, this paper discusses the applicability and performance of these valves operated as phase diffraction gratings in HDTV projection systems. A numerical method for evaluating performance and optimizing design parameters is presented. The resulting model is used to consider design improvement to increase the modulation efficiency and to adapt the projector to use unpolarized light as well as linearly polarized light. The modeling results are used to determine and optimize the parameters of the liquid crystal panel, such as, the refractive index of the liquid crystal, the thickness of liquid crystal cells, and the width of panel pixels.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/15121
- Subject Headings
- High definition television, Liquid crystals, Liquid crystal devices
- Format
- Document (PDF)
- Title
- A novel DSP scheme for image compression and HDTV transmission.
- Creator
- Dong, Xu., Florida Atlantic University, Sudhakar, Raghavan, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The main objective of the research is to develop computationally efficient hybrid coding schemes for the low bit implementations of image frames and image sequences. The basic fractal block coding can compress a relatively low resolution image efficiently without blocky artifacts, but it does not converge well at the high frequency edges. This research proposes a hybrid multi-resolution scheme which combines the advantages of fractal and DCT coding schemes. The fractal coding is applied to...
Show moreThe main objective of the research is to develop computationally efficient hybrid coding schemes for the low bit implementations of image frames and image sequences. The basic fractal block coding can compress a relatively low resolution image efficiently without blocky artifacts, but it does not converge well at the high frequency edges. This research proposes a hybrid multi-resolution scheme which combines the advantages of fractal and DCT coding schemes. The fractal coding is applied to get a lower resolution, quarter size output image and DCT is then used to encode the error residual between original full bandwidth image signal and the fractal decoded image signal. At the decoder side, the full resolution, full size reproduced image is generated by adding decoded error image to the decoded fractal image. Also, the lower resolution, quarter size output image is automatically given by the iteration function scheme without having to spend extra effort. Other advantages of the scheme are that the high resolution layer is generated by error image which covers the bandwidth loss of the lower resolution layer as well as the coding error of the lower resolution layer, and that it does not need a sophisticated classification procedure. A series of computer simulation experiments are conducted and their results are presented to illustrate the merit of the scheme. The hybrid fractal coding method is then extended to process motion sequences as well. A new scheme is proposed for motion vector detection and motion compensation, by judiciously combining the techniques of fractal compression and block matching. The advantage of this scheme is that it improves the performance of the motion compensation, while keeping the overall computational complexity low for each frame. The simulation results on realistic video conference image sequences support the superiority of the proposed method in terms of reproduced picture quality and compression ratio.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/12407
- Subject Headings
- Hybrid integrated circuits, Image compression, Fractals, Image processing--Digital techniques, High definition television
- Format
- Document (PDF)