Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 30 for “"Image quality metrics"”.
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Scene-Dependency of Spatial Image Quality Metrics
… imaging performance and the modelling of spatial image quality in digital capturing systems. Spatial imaging performance and image quality relate to the objective and subjective reproduction of luminance contrast signals by the system, respectively; they are critical to overall perceived image …
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A quantitative analysis and assessment of the performance of image quality metrics
Image quality assessment addresses the distortion levels and the perceptual quality of a restored or corrupted image. A plethora of metrics has been developed to that end. The usual mean of success of an image quality metric is their ability to agree with the opinions of human subjects, often …
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Modulation transfer function measurements, image quality metrics, and subjective image quality for soft-copy color images
… of spatial frequency manipulation of color images and its impact on subjective image quality were examined by measuring subjective image quality and the changes in several prominent image quality metrics. The Modulation Transfer Function Area (M1F A), the Square Root Integral (SQRI), the …
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An image quality analysis of ANVIS-6 night vision goggles
… an effort to relate ANVIS-6 Night Vision Goggle image quality to user performance. The purpose was to determine which of five image quality metrics best related to performance tasks. The image quality metrics examined Modulation Transfer Function Area (MTFA), Integrated Contrast Sensitivity …
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Inverse Scattering Image Quality with Noisy Forward Data
Image quality metrics for several inverse scattering methods and algorithms are presented. Analytical estimates and numerical simulations provide a basis for poor image quality diagnostics. The limitations and noise behavior of reconstructed images are explored analytically and empirically using a …
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Effects of field of view, MTF shape, and noise upon the perception of image quality and motion
… first was to develop and evaluate a metric of image quality that incorporates a model of suprathreshold contrast and is based upon the perceived magnitude of suprathreshold contrast. The second objective was to determine the effects that common display characteristics, such as MTF shape, noise, …
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Effects of luminance, color, and spatial frequency variations on perceived image quality
… and spatial frequency content on the perceived image quality of a soft-copy color image. A secondary objective was to test the robustness of selected image quality metrics (MTFA, SQRI, and ICS) to the color variations as measured by the change in correlations between the perceived quality …
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The effect of scene content on image quality
Device-dependent metrics attempt to predict image quality from an ‘average signal’, usually embodied on test targets. Consequently, the metrics perform well on individual ‘average looking’ scenes and test targets, but provide lower correlation with subjective assessments when working with a variety …
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The (travel) times they are a changing : a computational framework for the diagnosis of non-alcoholic fatty liver disease (NAFLD)
… is lower than that in a healthy liver and 2) the quality of an ultrasound image is maximized when the beamforming speed of sound used in image formation matches the speed in the medium under examination. The proposed method uses image brightness and sharpness as quantitative image-quality metrics …
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An analytic model to predict detection threshold and performance data for misconvergence on a shadow-mask CRT
… of a visual task and on subjective estimates of image quality. While subjective quality and threshold detection have previously been investigated for some color combinations, the three tasks (i.e., threshold detection, visual task performance, and subjective estimates) have not been …
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Advanced Algorithmic Approaches for Improving Image Quality in 2D and 3D Holographic Displays
… and focuses specifically on potential image quality improvements based on algorithmic development. The thesis builds a holographic display system prototype and reconstructs established 3D scenes and real-world scenes using commercially available RGB-D cameras. By closely examining the …
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Digital signal processing techniques for optical coherence tomography : OCT and OCT image enhancement
… to improve the flexibility, functionality, and image quality of ultrahigh resolution optical coherence tomography (OCT) systems. To reduce the dependence of OCT research systems on fixed analog electronics and to improve overall system flexibility, a digital demodulation scheme implemented …
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Quantitative evaluation of image quality in CT imaging using iodine and nanoparticle-based contrast agents
… of concentrations and nanoparticle sizes. CT Image quality was assessed in terms of image signal intensity, CNR, and image noise. Results: For all agents, lower tube voltage (kVp) increased both signal intensity and CNR, although this improvement came with elevated noise levels. For ICM, …
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Deep Learning Domain Adaptation in Brain MRI: Investigating Motion Mitigation in Adult and Neonatal Scans
… critically assesses the reliability of common image quality metrics (IQMs). The analysis reveals that traditional metrics are often insensitive to subtle motion and can even yield paradoxical results, where motion-corrupted images appear higher in quality than corrected ones. Overall, this work …
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Backscatter Spatial Coherence for Ultrasonic Image Quality Characterization: Theory and Applications
… and dynamically tune imaging parameters based on image quality feedback, represent a promising solution for reducing the user-dependence of ultrasound. The efficacy of such systems, however, depends on the ability to accurately and reliably measure in vivo image quality with minimal user …
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Optimization of Fast MR Imaging Technologies using the Case-PDM to Quantitatively Assess Image Quality
… an extraordinary number of ways to create an MR image, and the number seems to grow daily. In almost all cases, images will be viewed by radiologists to make a diagnosis, to stage a disease, to apply a treatment, and/or to assess a treatment. Since images are viewed, one needs to assess visual …
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Active sampling, scaling and dataset merging for large-scale image quality assessment
… subjective measurements is difficult is image quality assessment. The results from these studies are used to develop and train automated or objective image quality metrics, which, with the advent of deep learning, require large amounts of versatile and heterogeneous data. I present three …
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A human spatial-chromatic vision model for evaluating electronic displays
… color matrix displays) which degrade image quality. Based on this analysis, it is suggested that a comprehensive metric should measure image quality in terms of transmitted signal and noise modulation, both achromatic and chromatic. Moreover, it is suggested that these signal and noise …
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Characterizing the perceived quality degradation of still-camera motion blur
… of the associated degradation in photographic image quality. In the first experiment, motion of a hand-held 35-mm single-lens-reflex camera was measured using inertial sensors while film was simultaneously exposed. Thirty-two subjects photographed two studio scenes at 1/60-s, 1/30-s, 1/15-s, …
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CRT anti-glare treatments, image quality, and human performance
… effort. Phase I investigated the physical image quality of 16 mesh, etched, and quarterwave antireflection filters for varying levels of filter transmissivity. Three levels of ambient lighting and two levels of monochrome CRT resolution were combined factorially with the filters. In …
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