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Comparison Of The Mid-Frequency Line Edge Noise Algorithms Of Jim Hamerly And Yigal Gur For The Best Correlation To The Psychophysical Defect Known As Raggedness, Kevin Huff
Theses
A study was conducted to compare the mid-frequency line edge noise algorithms of Jim Hamerly and Yigal Gur. Comparisons were made to determine which algorithm correlated best with the psychophysical defect known as raggedness. Tests were conducted on "standard" observers using a series of test images with varying amounts of edge noise. A master image was produced photographically and ensuing images generated with random error using electrophotographic processes. Scanning of the images to determine output metric values was done on a Zeiss microdensitometer. It was found that with electrophotographic prints, the Hamerly algorithm has a correlation coefficient of .83. Determination …
Study Of The Graininess Models Using The Macintosh Computer, Apiwat Nutavej
Study Of The Graininess Models Using The Macintosh Computer, Apiwat Nutavej
Theses
This study attempts to develop a Macintosh program that is able to simulate the photographic graininess models, to perform a Fast Fourier Transform, to plot a three dimensional graph, and to display a digitized image. Because of these four integrated functions, the program could become a useful tool in imaging science. The potential advantages include ease of use and the visual interaction between computer and user. When comparing the simulation results among three density models and four granularity models of random dots used in this study, the answers are found to be in close agreement with the hypothetical equations, with …
A Quantitative Image Evaluation Study Of A Concurrent Photon Amplification Treated Emulsion, Konrad E. Kern
A Quantitative Image Evaluation Study Of A Concurrent Photon Amplification Treated Emulsion, Konrad E. Kern
Theses
A study was performed to evaluate the effect of concurrent photon amplification (CPA) on Kodak Tri-X Pan emulsion in regard to image quality. The study evaluated detective quantum efficiency (DQE), modulation transfer function (MTF), and information content (IC) as a function of exposure in a comparison between normal exposure and CPA. The results showed CPA to enhance image quality relative to normal exposure at very low exposure levels. As the exposure was increased, normally exposed images became comparable and then exceeded CPA exposures in image quality. The exposure level at which normal exposure became preferential was distinct with each image …
Second Order Coherent Power Spectra, Brian A. Gorin
Second Order Coherent Power Spectra, Brian A. Gorin
Theses
The relationship between second order stochastic processes and coherent power spectra are explored for developed grain size frequency distributions of silver halide emulsion/developer combinations. Although Wiener spectra represent incoherent power spectra, the coherent case has been unresolved due to the difficulty of filtering the optical system effect. The emulsion plates were exposed with a uniform irradiance distribution from an incoherent tungsten source to create a series of uniform density samples. Conventional processing chemistry is utilized with substitution of different developer types, from predominantly physical development to direct chemical development. The exposed and processed density samples were liquid gated with refractive …
Perception Of Graininess In Complex Photographic Images Through Objective And Subjective Comparison, Glenn E. Mcneill
Perception Of Graininess In Complex Photographic Images Through Objective And Subjective Comparison, Glenn E. Mcneill
Theses
A model previously used for the perception of graininess in uniform-density images that exist in electrophotography, has been verified for use in silver-halide photography. In addition, a model has been developed which estimates the sensation of graininess in photographic images of non -uniform density. Given the relationship between graininess and density in uniform-density images, the graininess in a complex image is weighted by the frequency of occurrence of each measured density in the image. Such an analysis is compared to subjective evaluations. It is shown that the graininess model is useful in predicting the sensation of graininess in photographs.
Haloid Camera Xerography, Ronald Ruhl Talbott
Image Restoration By Selective Short Space Spectral Subtraction, Rose M. Korte
Image Restoration By Selective Short Space Spectral Subtraction, Rose M. Korte
Theses
Image restoration by short space spectral subtraction has been applied recursively to a photographic system in an attempt to increase the signal to noise ratio proportionally to the amount of optical density present. The image is smoothed in the frequency domain a small space at a time based on the power spectrum at a given density level. The method is a variable filter that is a function of photographic density.
An Investigation Of A Mathematical Model To Characterize The Nonlinear Nature Of A Lithographic Film System, David S. Holbrook
An Investigation Of A Mathematical Model To Characterize The Nonlinear Nature Of A Lithographic Film System, David S. Holbrook
Theses
An attempt was made to obtain a set of spatial transfer functions which would allow the prediction of output effective exposure distributions for a nonlinear lithographic film system. Slit exposures were used as one-dimensional system inputs. It was proposed that the use of slits would allow the calculation of a general system transfer function to be simplified. The mathematical model chosen to describe this nonlinear transfer was shown to be invalid due to the nonlinear relationship of small area system gain (small area output effective exposure divided by the input exposure) as a function on input exposure. The model,, based …
Granularity: Investigating Equations That Convert (T) To (D), Frederick Catt
Granularity: Investigating Equations That Convert (T) To (D), Frederick Catt
Theses
An investigation was done on three published expanded equations, that convert (T) to (D). T. Celio, J. Altman and M. Abouelata published equations of the same form, but with differing constants. Their equations were derived by using an assumed square-wave transmittance trace. The investigation was to find the best predictor of (D) from (T) . Both practical and simulation tests were run. The density range was extended, to check for failure at both high and low densities. Standard granularity measurement procedures were followed as close as possible. Results, from the practical tests, showed Altman 's equation the best predictor of …
Comparison Of The Derivative-Transform Edge Gradient Analysis Technique To Tatian's Method Of Edge Gradient Analysis, Varying Random Noise, Truncation Interval And Sampling Internal On Analytical Edges, Robert Laflesh
Theses
The following work has been computer simulated. A cumulative gaussian step response and the step response of a photographic emulsion 1 were taken through the derivative-transform edge gradient analysis technique and Tatian's method of analysis. Random noise levels, truncation intervals and sampling intervals on the analytic edges were varied to determine their influence on each technique. The variance and means of the calculated m.T.F.s were then statistically tested for no difference of the two techniques. The exact noise free M.T.F. was also calculated and compared to the M.T.F.s calculated by the two techniques. The results show a statistical difference in …