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Complexity reduction tools for MPEG-2 to H.264 video transcoding
Title
Complexity reduction tools for MPEG-2 to H.264 video transcoding.
Creator
Furht, Borko, Kalva, Hari, Petljanski, Branko
PURL
http://purl.flvc.org/fcla/dt/332412
Subject Headings
Digital video., Video recording --Standards., MPEG (Video coding standard)., Digital communications.
Format
Document (PDF)
Image improvement using dynamic optical low-pass filter
Title
Image improvement using dynamic optical low-pass filter.
Creator
Petljanski, Branko., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
Professional imaging systems, particularly motion picture cameras, usually employ larger photosites and lower pixel counts than many amateur cameras. This results in the desirable characteristics of improved dynamic range, signal to noise and sensitivity. However, high performance optics often have frequency response characteristics that exceed the Nyquist limit of the sensor, which, if not properly addressed, results in aliasing artifacts in the captured image. Most contemporary still and...
Show moreProfessional imaging systems, particularly motion picture cameras, usually employ larger photosites and lower pixel counts than many amateur cameras. This results in the desirable characteristics of improved dynamic range, signal to noise and sensitivity. However, high performance optics often have frequency response characteristics that exceed the Nyquist limit of the sensor, which, if not properly addressed, results in aliasing artifacts in the captured image. Most contemporary still and video cameras employ various optically birefringent materials as optical low-pass filters (OLPF) in order to minimize aliasing artifacts in the image. Most OLPFs are designed as optical elements with a frequency response that does not change even if the frequency responses of the other elements of the capturing systems are altered. An extended evaluation of currently used birefringent-based OLPFs is provided. In this work, the author proposed and demonstrated the use of a parallel optical window p ositioned between a lens and a sensor as an OLPF. Controlled X- and Y-axes rotations of the optical window during the image exposure results in a manipulation of the system's point-spread function (PSF). Consequently, changing the PSF affects some portions of the frequency components contained in the image formed on the sensor. The system frequency response is evaluated when various window functions are used to shape the lens' PSF, such as rectangle, triangle, Tukey, Gaussian, Blackman-Harris etc. In addition to the ability to change the PSF, this work demonstrated that the PSF can be manipulated dynamically, which allowed us to modify the PSF to counteract any alteration of other optical elements of the capturing system. There are several instances presented in the dissertation in which it is desirable to change the characteristics of an OLPF in a controlled way., In these instances, an OLPF whose characteristics can be altered dynamically results in an improvement of the image quality.
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Date Issued
2010
PURL
http://purl.flvc.org/FAU/1927613
Subject Headings
Image processing, Digital techniques, Signal processing, Digital techniques, Frequency response (Dynamics), Polymers and polymerization, Optical wave guides
Format
Document (PDF)
wavelet-based detector for underwater communication
Title
A wavelet-based detector for underwater communication.
Creator
Petljanski, Branko., Florida Atlantic University, Erdol, Nurgun, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
The need for reliable underwater communication at Florida Atlantic University is critical in transmitting data to and from Autonomous Underwater Vehicles (AUV) and remote sensors. Since a received signal is corrupted with ambient ocean noise, the nature of such noise is investigated. Furthermore, we establish connection between ambient ocean noise and fractal noise. Since the matched filter is designed under the assumption that noise is white, performance degradation of the matched filter due...
Show moreThe need for reliable underwater communication at Florida Atlantic University is critical in transmitting data to and from Autonomous Underwater Vehicles (AUV) and remote sensors. Since a received signal is corrupted with ambient ocean noise, the nature of such noise is investigated. Furthermore, we establish connection between ambient ocean noise and fractal noise. Since the matched filter is designed under the assumption that noise is white, performance degradation of the matched filter due non-white noise is investigated. We show empirical results that the wavelet transform provides an approximate Karhunen-Loeve expansion for 1/f-type noise. Since whitening can improve only broadband signals, a new method for synchronization signal design in wavelet subspaces with increased energy-to-peak amplitude ratio is presented. The wavelet detector with whitening of fractal noise and detection in wavelet subspace is shown. Results show that the wavelet detector improves detectability, however this is below expectation due to differences between fractal noise and ambient ocean noise.
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Date Issued
2001
PURL
http://purl.flvc.org/fcla/dt/12778
Subject Headings
Wavelets (Mathematics), Underwater acoustics
Format
Document (PDF)