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The effects of target orientation on the dynamic contrast sensitivity functionCroxton, Craig A. 05 September 2009 (has links)
Much research has been accomplished on the effects of target motion on visual acuity. Research has also been accomplished on the effects of target orientation on visual acuity. The contrast sensitivity function (CSF) also has been studied as a predictor of visual performance under dynamic conditions. However, no previous studies have combined these areas of research and examined the effect of target orientation on the Dynamic Contrast Sensitivity Function (DCSF).
This study examined the effects of target orientation on the DCSF and found that diagonal lines (relative to vertical lines) decreased the DCSF, on average over 19%. Previous research indicated that target motion reduces contrast sensitivity, and at the same time shifts the peak of the CSF toward lower spatial frequencies. This study rotated the target in a circular path (velocities of 22°, 30°, and 39°/second) and found a similar decrement and shift in the CSF.
The main effects for Target Orientation, Velocity, and Spatial Frequency and their two-way interactions were all statistically significant (p ≤ .05). Additionally, all velocity conditions were found to be statistically different from each other. These results advance the validity of our measurement device and procedures.
The effect of target orientation presumably is a function of the magnocellular and parvocellular visual pathway systems and their roles in the detection of form and motion. While the magnocellular system is primarily responsible for detection of motion and large objects, the parvocellular system is responsible for the detection of color and fine detail. / Master of Science
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The effects of target vibration on the human contrast sensitivity functionAdams, William F. 10 November 2009 (has links)
A great deal of research has been conducted on the effects of vibration on visual acuity. The human contrast sensitivity function (CSF) has also been studied extensively as a predictor of visual performance under real-world conditions. However, no previous studies have combined the two lines of research and examined the effect of vibration on the CSF. Prior research indicates that increasing rates of vibration correspond to a decrease in traditional measures of visual acuity. However, other studies indicate that motion enhances target detection. The present study examined the effects of vibration upon the CSF and found that vibration lowers the threshold of detection for low spatial frequencies but raises the threshold for high spatial frequencies. A loss of contrast at high spatial frequencies due to retinal "smear" may be the cause of this increase in high spatial frequency thresholds under vibration. Physiological mechanisms of motion detection, direction selectivity, and visual pathways are also discussed. This study may have important implications for aerospace medicine and occupations which demand viewing a target or instrument panel under conditions of vibration. / Master of Science
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Fite FuaiteMcElwaine, Donal Padraig 02 December 2016 (has links)
Exploration of the architectural re-purposing of a historic building ruin with the goal of maintaining and emphasizing its current character and state of decay. Simultaneously examining how new interventions can clearly achieve modern expectations of function and enclosure, while allowing the character of the existing structure to be minimally impacted. The intervention in the historic building fabric demonstrates how new materials and construction techniques allow for a distinct contrast between old and new, and how the two can work harmoniously together. Specifically integrates new glued-laminated timber frame structure in contrast to existing concrete walls, testing a general case for the potential power of interventions and adaptive reuse to be a means to a rebirth and retelling of the stories of existing buildings. / Master of Architecture
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Gallery design focused on contrast & dynamismKwun, Joon Bum January 1996 (has links)
The purpose of this study is, first of all, to establish contrast and dynamism as a method to figure out the static and uniform experience through space. Second, through a study of books and an analysis of previous works of other architects, it will give a direction on how the actual design would be used in reality by finding the effects of contrast and dynamism, and finally, based on the analysis above, it will show a gallery design with contrast and dynamism, which will ultimately provide a guide to a better or more vivid spatial composition.
This study provides an understanding of how the perceptual contrast and dynamism not only appear on interior, but also on exterior space composition. Works of great contemporary architects, focusing on exhibition buildings were chosen for the analysis. A classification of the effects that generate contrast and dynamism can be different by various standards. Since there have not been any previous studies of a gallery design, this analysis is classified subjectively based on documents.
The site is in the Olympic Park, Seoul, South Korea. The park has a total of 291 hectares, which takes a good three hours to walk all around the Olympic Park on foot. There are six stadiums, such as cycling, fencing, weight-lifting, gymnastics, tennis and swimming.
The park has also an open-air Sculpture Park with its over 200 modern sculptures in stone, metal, timber and glass, donated in celebration of the Olympics by the artists from the 66 participating countries in the World International Open Air Sculpture Exhibition. Near the sports venues is a lake with water foundation and some lawn areas. / Master of Architecture
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Contrast Sensitivity to One- and Two-Dimensional Luminance PatternsPersaud, Steven S. 14 May 2004 (has links)
Contrast sensitivities to one- and two-dimensional luminance patterns were compared in a two-alternative forced choice (2AFC) experiment. Space-averaged luminance was also manipulated. Statistical analyses revealed a main effect of stimulus dimension (p < .05) and no effect of space-averaged luminance. The main effect of stimulus dimension was explained in terms of an on-center, off-center receptive field model combined with watershed spatial vision behavior at spatial frequencies below 1 cycle-per-degree (cpd). The non-significant result for space-averaged luminance was explained by the limited range of manipulation of the variable. Two-dimensional luminance patterns were suggested as ideal patterns for reconciling grating-based spatial vision research with spatial vision behavior in an ecological context. Future research directions are suggested. / Master of Science
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Fluoroscopy, contrast agents and image-guided interventionChaplin, Elaine, Culpan, Gary January 2008 (has links)
No
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Context sensitive cardiac x-ray imaging: a machine vision approach to x-ray dose controlKengyelics, S.M., Gislason-Lee, Amber J., Keeble, C., Magee, D.R., Davies, A.G. 21 September 2015 (has links)
Yes / Modern cardiac x-ray imaging systems regulate their radiation output based on the thickness of the
patient to maintain an acceptable signal at the input of the x-ray detector. This approach does not account for the
context of the examination or the content of the image displayed. We have developed a machine vision algorithm
that detects iodine-filled blood vessels and fits an idealized vessel model with the key parameters of contrast,
diameter, and linear attenuation coefficient. The spatio-temporal distribution of the linear attenuation coefficient
samples, when appropriately arranged, can be described by a simple linear relationship, despite the complexity
of scene information. The algorithm was tested on static anthropomorphic chest phantom images under different
radiographic factors and 60 dynamic clinical image sequences. It was found to be robust and sensitive to
changes in vessel contrast resulting from variations in system parameters. The machine vision algorithm
has the potential of extracting real-time context sensitive information that may be used for augmenting existing
dose control strategies. / Project PANORAMA, funded by grants from Belgium, Italy, France, the Netherlands, United Kingdom, and the ENIAC Joint Undertaking.
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Machine vision image quality measurement in cardiac x-ray imagingKengyelics, S.M., Gislason-Lee, Amber J., Keeble, C., Magee, D., Davies, A.G. 16 March 2015 (has links)
Yes / The purpose of this work is to report on a machine vision approach for the automated measurement of x-ray
image contrast of coronary arteries lled with iodine contrast media during interventional cardiac procedures.
A machine vision algorithm was developed that creates a binary mask of the principal vessels of the coronary
artery tree by thresholding a standard deviation map of the direction image of the cardiac scene derived using a
Frangi lter. Using the mask, average contrast is calculated by tting a Gaussian model to the greyscale pro le
orthogonal to the vessel centre line at a number of points along the vessel. The algorithm was applied to sections
of single image frames from 30 left and 30 right coronary artery image sequences from di erent patients. Manual
measurements of average contrast were also performed on the same images. A Bland-Altman analysis indicates
good agreement between the two methods with 95% con dence intervals -0.046 to +0.048 with a mean bias of
0.001. The machine vision algorithm has the potential of providing real-time context sensitive information so
that radiographic imaging control parameters could be adjusted on the basis of clinically relevant image content. / Project PANORAMA, funded by grants from Belgium, Italy, France, the Netherlands, and the United Kingdom, and the ENIAC Joint Undertaking.
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Effective Visual Design for Proposal WritingJohnston, Allegra Christine 23 April 2003 (has links)
The field of document design has gained considerable attention over the past couple of decades. New technology has drastically increased the design possibilities for writers, and researchers are gaining greater insight into the way that readers interact with the visual elements of their texts. This has led to an explosion in the availability of guidance on document design, but there are still areas where the research is incomplete. One of these areas concerns a common but important type of document: the proposal. There are numerous guides on proposal writing, but most of them are concerned with content and give little attention to document design. Since successful proposals are crucial to both the business and non-profit arenas, it is important that the documents are accessible and make a good impression on reviewers. Good document design can help.
In this study I took the existing research on document design and developed a set of questions meant to address the different elements of document design. I tested a sampling of both grant proposals and contract proposals using those questions with a system of scoring based on Likert scaling. I combined the quantitative results with qualitative responses from interviews in order to gain insight regarding the overall effect of visual design elements in proposals. The results of this study showed that there are certain elements of document design (such as layout or contrast) that are important to proposals, but that non-design factors (such as cost or experience) usually outweigh the design for evaluation purpose. / Master of Arts
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Red-green and blue-yellow mechanisms are matched in sensitivity for temporal and spatial modulation.McKeefry, Declan J., Murray, I.J., Kulikowski, J.J. January 2001 (has links)
No / The spatial and temporal properties of human colour vision are examined using isoluminant, red¿green and blue¿yellow tritanopic gratings. Chromatic sensitivity is found to be low-pass as a function of both spatial and temporal frequency along all the chromatic axes investigated, including the tritanopic confusion lines employed to examine the properties of the S-cone driven mechanism. Comparison of sensitivity to on-off and contrast reversing stimuli indicates that transient mechanisms contribute to the detection of red¿green patterns but that the detection of S-cone specific patterns is governed by sustained mechanisms. By compensating for transient contributions to red¿green sensitivity, it is shown that sensitivity of chromatic mechanisms dominated by L- and M-cone input are closely matched to those with S-cone input.
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