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.
Results
Showing 1 to 9 of 9 for “"Visual image quality"”.
-
Evaluation of an Objective Visual Image Quality-Based Method to Identify Spectacle Corrections for Individuals with Keratoconus
… approximation of the neural performance of the visual system; and 3) an objective method to search the refractive space in the phoropter. Methods: This work was conducted in two parts. First, a direct comparison was made between this objective method of identifying a spectacle prescription, …
-
AP pelvis x-ray imaging on a trolley: the impact of trolley design, mattress design and radiographer practices on image quality and radiation dose
… mattress design and radiographer practice on image quality and radiation dose for AP pelvis imaging on a trolley in order to optimise this imaging examination. AP pelvis was chosen as the focus of this thesis due to the frequency of this examination on a trolley and the dose implication …
-
Techniques for Approximating Optimal Linear Estimators of Multidimensional Data
… a time-series of optical coherence tomography images and propose a blind estimator that improves visual image quality by reducing the speckle noise that is characteristic of coherent imaging. Next, a blind estimator for fMRI data is constructed that significantly improves the ability to detect …
-
Rate control and bit allocations for JPEG transcoding
An image transcoder that produces a baseline JPEG file from a baseline JPEG input is developed. The goal is to produce a high quality image while accurately meeting a filesize target and keeping computational complexity-especially the memory usage and number of passes at the input image--low. …
-
Establishing an evidence-base for erect pelvis radiography : positioning, radiation dose and image quality
… radiographic positioning, radiation dose and image quality. Methods: The experimental work described in this thesis was conducted in three phases. Each phase has its own methods with the purpose of achieving a specific set of aims. Phase One was the evaluation of the postural effects of …
-
Image usefulness of compressed surveillance footage with different scene contents
… systems) methods for the completion of visual tasks (e.g person identification). Image quality for police tasks has been defined as the image usefulness, or image suitability of the visual material to satisfy a visual task. It is not necessarily affected by any artefact that may affect …
-
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 …
-
Reversible and imperceptible watermarking approach for ensuring the integrity and authenticity of brain MR images
… workflow has many circumstances in which the image data can be manipulated both within the secured Hospital Information Systems (HIS) and outside, as images are viewed, extracted and exchanged. This potentially grows ethical and legal concerns regarding modifying images details that are …
-
Optimising image quality and radiation dose with a focus on geometry and attenuation
… balance is achieved between acquiring images of diagnostic quality and the radiation dose received by the patient. Pragmatic, simple and effective methods are essential to ensure that optimisation techniques are adopted into clinical practice.The six papers presented within this thesis …