Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 21 of 21
Full-Text Articles in Entire DC Network
Laser Driven Variable Dot Size Thermal Wax Transfer Printing, Steven Van Korol
Laser Driven Variable Dot Size Thermal Wax Transfer Printing, Steven Van Korol
Theses
A digital image hardcopy device has been designed using a laser exposure mechanism, a pigmented wax /resin donor ink sheet, and an opaque receiver sheet. The writing system relies on image-wise thermal mass transfer of molten ink to the receiver in order to produce high resolution output. With the receiver media and a specially designed donor ribbon being held to a platen through vacuum pressure, a pulsed solid-state diode pumped near IR NdrYAG laser provides the energy necessary to complete the thermal transfer process. By varying pulse width, dot size variation is possible. A mathematical model was developed to explain …
Design And Performance Evaluation Of A Modular Imaging Spectrometer Instrument, Xiaofan Feng
Design And Performance Evaluation Of A Modular Imaging Spectrometer Instrument, Xiaofan Feng
Theses
This thesis involved the design and testing of a modular imaging spectrometer instrument (MISI), which can provide hyperspectral image data at a very high ground resolution. The instrument can serve as an airborne laboratory for many remote sensing applications. The optical/mechanical/electrical system was designed using a system engineering approach with emphasis on system and sub-system modulation transfer function (MTF) analysis. Extensive modeling was used to predict the system performance and to aid the design trade process. Many sensor testing methodologies were developed to evaluate the performance of this electro-optical imaging system. The system engineering approach, the modeling tools developed, and …
Iterative Morphological Filters And Application In Document Restoration, Yeqing Zhang
Iterative Morphological Filters And Application In Document Restoration, Yeqing Zhang
Theses
The binary nature of document degradation decides the suitability of morphological methods for restoration. Although the computational burden in morphological filter design can be mitigated by imposing constraints on the filter and employing the morphological filter MAE theorem in an efficient search strategy, the design constraints on the filter limit the performance of single-pass filter. It has been shown that iterative morphological filters can outperform single-pass filters. The investigation of iterative morphological filter design for image restoration is the main contribution of the present thesis. The study of iterative morphological filter design provides the understanding in depth of how filters …
Signal Detection Using Pseudocolor Scales, Hong Li
Signal Detection Using Pseudocolor Scales, Hong Li
Theses
Historically, gray scale has been the standard method of displaying univariate medical images. A few color scales have been proposed and evaluated, but have had little acceptance by radiologists. It is possible that carefully desired scales might give lesion detection performance that equals gray scale and improves performance of other tasks. We investigated 13 display scales including the physically linear gray scale, the popular rainbow scale and the other 1 1 perceptually linearized scales. One was the hot body (heated object) scale and the other 10 were spiral trajectories in the CIELAB uniform color space. The experiments were performed using …
An Investigation Into The Distuibution Of Portable Documents In A Prepress Environment, Timothy Conroy
An Investigation Into The Distuibution Of Portable Documents In A Prepress Environment, Timothy Conroy
Theses
Portable document files (PDF's) are used in many types of environments; such as, office, world wide web, and desktop publishing to name a few. PDF technology allows electronic documents to become truly portable. PDF files maintain their original look and feel across various computer systems and platforms. PDF use in a prepress environment was tested by creating various electronic mechanicals with numerous file formats and having these PDF files imaged across the country on various high resolution imagesetting devices. It has been determined that PDF files can be used in a prepress environment at this point in time in some …
Neural Network For Optimization Of Binary Computer-Generated Hologram With Printing Model, Guo Li
Neural Network For Optimization Of Binary Computer-Generated Hologram With Printing Model, Guo Li
Theses
Hopfield neural nets are used to optimize point-oriented binary computer-generated holograms (CGHs). It can be considered as a parallel and iterative 'halftoning' process in the spatial frequency domain. The results are comparable to other iterative methods but require shorter computation times. In this process, the generation of the CGH by FFT, binarization, and IFFT is viewed as a "black box" with inputs and outputs consisting of 512 arrays containing an object of size 64 . The neural-network optimization feeds back the Fourier transform of the reconstruction error to update the neuron states, which correspond to the samples of the continuous …
A Comparison Of The Performance Of Non-Parametric Classifies With Gaussian Maximum Likelihood For The Classification Of Multispectral Remotely Sensed Data, Steven Nessmiller
A Comparison Of The Performance Of Non-Parametric Classifies With Gaussian Maximum Likelihood For The Classification Of Multispectral Remotely Sensed Data, Steven Nessmiller
Theses
This study compares the performance of two non-parametric classifiers and Gaussian Maximum Likelihood (GML) for the classification of LANDSAT TM 30-meter resolution six-band data. The mathematical assumptions made in developing GML are valid if the pixels that constitute the training classes are normally distributed. Since it requires a model of the data, GML is termed a "parametric" classifier. Of current interest are new classification methodologies that make no assumptions about the statistical distribution of the pixels in the training class; these approaches are termed "non-parametric" classifiers. This study will compare the n-Dimensional Probability Density Function (nPDF) essentially a projection technique …
The Effect Of Image Content On Color Difference Perceptibility, Susan Farnand
The Effect Of Image Content On Color Difference Perceptibility, Susan Farnand
Theses
Considerable work has been conducted regarding the perceptibility of color differences for simple images such as uniform color patches. From this work comes such tools as the MacAdam ellipses. Less is known regarding color difference perceptibility when complex images are involved. However, the proliferation of desktop publishing equipment and the increasingly technically elegant accompanying software makes questions around this topic both more facile and more relevant to study. The information that could be gleaned may be useful for the design of color printer algorithms or other imaging systems. The objective of this research was to examine the impact of image …
Matched Wavelet Construction And Its Application To Target Detection, Joseph Chapa
Matched Wavelet Construction And Its Application To Target Detection, Joseph Chapa
Theses
This dissertation develops a new wavelet design technique that produces a wavelet that matches a desired signal in the least squares sense. The Wavelet Transform has become very popular in signal and image processing over the last 6 years because it is a linear transform with an infinite number of possible basis functions that provides localization in both time (space) and frequency (spatial frequency). The Wavelet Transform is very similar to the matched filter problem, where the wavelet acts as a zero mean matched filter. In pattern recognition applications where the output of the Wavelet Transform is to be maximized, …
Temporal Sampling Of Forward Looking Infra-Red Imagery For Sub-Resolution Enhancment Post-Processing, Serge Dutremble
Temporal Sampling Of Forward Looking Infra-Red Imagery For Sub-Resolution Enhancment Post-Processing, Serge Dutremble
Theses
Forward Looking Infra Red (FLIR) and RADAR images are examples of low resolution and inherently noisy images. These images are often very sensitive to weather conditions or imaging system characteristics and are usually difficult to evaluate. Interpretation of such images is often restricted to specialists with many years of experience. We propose a quantitative evaluation of two Post-Processing methods of combining temporally close sequential video FLIR images to produce sub-pixel resolution still images. Although we can conceive many different methods to increase the resolution of a video image, this Thesis studies methods based on subpixel interpolation and subpixel separate sampling. …
An Examination Of Distributional Assumptions In Landsat Tm Imagery, Elizabeth Frey
An Examination Of Distributional Assumptions In Landsat Tm Imagery, Elizabeth Frey
Theses
The first portion of this study checked water, vegetation, and urban class features of LANDSAT TM data for univariate normality using Pearson's system of frequency curves. Results indicated that of the 144 image bands tested 135 were determined to be normal in distribution. The second part of the study developed an image generator that uses the mean, covariance matrix and intraband correlation of LANDSAT TM images to create synthetic class scenes. Imagery composed of multiple synthetic class scenes, which ranged from normal to non-normal in their distributions, were classified using a maximum likelihood classifier. No significant difference in classification accuracy …
Polarization Modulation And Splicing Techniques For Stressed Birefringent Fiber, Risa Robinson
Polarization Modulation And Splicing Techniques For Stressed Birefringent Fiber, Risa Robinson
Theses
A study has been conducted in the areas of polarization modulation and splicing techniques for a polarization maintaining PANDA type fiber. Polarization modulation was achieved by compressing the fiber both along the fast and slow axes. A sensitivity of 16.69 rad/(g/um) and 27.56 rad/(g/um), corresponding to a maximum phase diffrerence of 2.39 radians and 3.96 radians for compressing along the x and y birefringent axis, respectively, was achieved, with the compression material complying to a 15 degree arc around the fiber circumference. Polarization cross coupling was measured to be 0.6% for compressing with a force of 1.3 g/um. Polarization cross …
Convergence Of Adaptive Morphological Filters In The Context Of Markov Chains, Yidong Chen
Convergence Of Adaptive Morphological Filters In The Context Of Markov Chains, Yidong Chen
Theses
A typical parameterized r-opening *r is a filter defined as a union of openings by a collection of compact, convex structuring elements, each of which is governed by a parameter vector r. It reduces to a single parameter r-opening filter by a set of structuring elements when r is a scalar sizing parameter. The parameter vector is adjusted by a set of adaptation rules according to whether the re construction Ar derived from r correctly or incorrectly passes the signal and noise grains sampled from the image. Applied to the signal-union-noise model, the optimization problem is to find the vector …
A Computational Analysis Of Observer Metamerism In Cross-Media Color Matching, Richard Alfvin
A Computational Analysis Of Observer Metamerism In Cross-Media Color Matching, Richard Alfvin
Theses
Standard color-matching functions are designed to represent the mean color-matching response of the population of human observers with normal color vision. When using these functions, two questions arise. Are they an accurate representation of the population? And what is the uncertainty in color-match predictions? To address these questions in the dual context of human visual performance and cross-media reproduction, a color-matching experiment was undertaken in which twenty observers made matches between seven different colors presented in reflective and transmissive color reproduction media and a CRT display viewed through an optical apparatus that produced a simple split field stimulus. In addition, …
Imaging Modes In Force Regulated Near-Field Scanning Optical Microscopy: Amplitude, Polarization, And Interference Contrast, Ricardo Toledo-Crow
Imaging Modes In Force Regulated Near-Field Scanning Optical Microscopy: Amplitude, Polarization, And Interference Contrast, Ricardo Toledo-Crow
Theses
This dissertation describes the force regulated near-field scanning optical microscope (NSOM) and two important adaptations: one for imaging polarization contrast with a linear response, and the other for interference imaging. An introduction to near- field optics is first presented, followed by a description of the background to this work that includes the relevant references to the literature and previous results. A simple theoretical description of the NSOM in terms of scalar fields is then presented, followed by an exposition of an early but relevant rigorous vectorial interpretation of the experiment. The basic force regulated NSOM is presented: its parts, operation, …
A Study Of Ellipsoidal Variance As A Function Of Mean Cielab Values In A Textile Data Set, Seth Ansell
A Study Of Ellipsoidal Variance As A Function Of Mean Cielab Values In A Textile Data Set, Seth Ansell
Theses
An analysis of the variances of a set of colored textile patches, sampled from the Scott-Munsell textile set, relative to their mean values, demonstrated several systematic trends. Overall, the amount of variance in the data as expressed by the shape and the orientation of the ellipsoids was found to be greatest in the L direction. Additionally, the shape and orientation of the ellipsoids was determined to be largely a function of chroma and lightness. No overall correlation was found between the distribution of the ellipsoidal volume and their hue or chroma. However, with exceptions, ellipsoidal volume peaked in patches with …
The Effect Of Instrumental Spherical Aberration On Visual Image Quality, Kevin P. Lyons
The Effect Of Instrumental Spherical Aberration On Visual Image Quality, Kevin P. Lyons
Theses
None provided.
The Effect Of Environment On Latent Image Formation And Stability, Sean O'Toole
The Effect Of Environment On Latent Image Formation And Stability, Sean O'Toole
Theses
This thesis uses an unsensitized emulsion and two chemically sensitized emulsions to investigate the effect of oxygen and water vapor on latent-image formation and stability. At exposure times that cause little or no low-intensity reciprocity failure, vacuum treatment of an emulsion can result in photographic speeds significantly lower than those found in a humidified environment. This is presumably due to competition between internal desensitization sites and surface electron traps for conduction-band electrons. Storage of a latent image in a humidified air environment will induce a speed loss in some emulsions. The unsensitized emulsion was most sensitive to environmental factors while …
Application Of Imaging System Geometric Models To A Synthetic Image Generation System, James M. Salacain
Application Of Imaging System Geometric Models To A Synthetic Image Generation System, James M. Salacain
Theses
A generalized imaging system geometric model has been incorporated into the Center for Imaging Science Digital Imaging and Remote Sensing Image Generation (DIRSIG) software system. The camera model is capable of simulating the geometric characteristics of frame cameras, line scanners and pushbroom scanners. The user of the model has the ability to define both the sensor internal orientation as well as provide time varying external orientation parameters. The model has been successfully validated through the use of both diagnostic simulated scenes as well as quantitative comparisons between actual imagery and simulated imagery.
Automated Detection Of Effective Scene Illuminant Chromaticity From Specular Highlights In Digital Images, Wayne Richard
Automated Detection Of Effective Scene Illuminant Chromaticity From Specular Highlights In Digital Images, Wayne Richard
Theses
An advanced, automated method is presented for determining an effective scene illuminant chromaticity (scene illuminant plus imaging system variables) from specular highlights in digital images subsequent to image capture. Underlying theories are presented based on a two component reflection model where the scene illuminant relative spectral power distribution is preserved in the specular component. Related methodologies for extracting scene illuminant information as well as alternative methods for achieving color constancy are presented along with factors which inhibit successful implementation. Following, development of a more robust algorithm is discussed. This algorithm is based on locating the center of convergence of a …
Statistical Characterization For 3-D Two-Component Tissue Models Using An Extended Microbeam Technique, Dongli Yang
Statistical Characterization For 3-D Two-Component Tissue Models Using An Extended Microbeam Technique, Dongli Yang
Theses
None provided.