The very nature of the fire fighting environment makes thermal degradation of turnout gear inevitable. Standards that are currently in place to ensure that new gear performs adequately for the protection of the fire fighter do not provide a quantitative measure for assessing this gear once it is in service. When the performance of the gear is compromised due to degradation, it could put the fire fighter wearing the gear at unnecessary risk. A non-destructive test that indicates the end of the useable service of the garment would be a benefit to the fire service. Full scale fire tests were conducted to suggest a range of heat fluxes that turnout gear specimens should be subjected to in order to simulate degradation caused by in-field use of the gear. A series of destructive tests were conducted on exposed specimens. A number of non-destructive tests were performed on the same specimens. The results of destructive and non-destructive tests were compared. This research explored some options for non-destructive tests of turnout gear. Digital image analysis and colorimetry were both offered as possibilities for a diagnostic test of this gear. Correlations between destructive performance tests and the colour changes of the outer shell fabric could be used to develop non-destructive tests to evaluate every garment owned by a department. More work is required to improve these test methods, but the door has been opened to better testing for in-use gear, and ultimately to provide better protection for the fire fighters who use this clothing.

The very nature of the fire fighting environment makes thermal degradation of turnout gear inevitable. Standards that are currently in place to ensure that new gear performs adequately for the protection of the fire fighter do not provide a quantitative measure for assessing this gear once it is in service. When the performance of the gear is compromised due to degradation, it could put the fire fighter wearing the gear at unnecessary risk. A non-destructive test that indicates the end of the useable service of the garment would be a benefit to the fire service. Full scale fire tests were conducted to suggest a range of heat fluxes that turnout gear specimens should be subjected to in order to simulate degradation caused by in-field use of the gear. A series of destructive tests were conducted on exposed specimens. A number of non-destructive tests were performed on the same specimens. The results of destructive and non-destructive tests were compared. This research explored some options for non-destructive tests of turnout gear. Digital image analysis and colorimetry were both offered as possibilities for a diagnostic test of this gear. Correlations between destructive performance tests and the colour changes of the outer shell fabric could be used to develop non-destructive tests to evaluate every garment owned by a department. More work is required to improve these test methods, but the door has been opened to better testing for in-use gear, and ultimately to provide better protection for the fire fighters who use this clothing.

A new framework for simulating the visual attention system in primates is introduced. The proposed architecture is an abstraction of existing approaches influenced by the work of Koch and Ullman, and Tompa. Each stage of the attentional hierarchy is chosen with consideration for both psychophysics and mathematical optimality. A set of attentional operators are derived that act on basic image channels of intensity, hue and orientation to produce maps representing perceptual importance of each image pixel. The development of such operators is realized within the context of a genetic optimization. The model includes the notion of an information domain where feature maps are transformed to a domain that more closely corresponds to the human visual system. A careful analysis of various issues including feature extraction, density estimation and data fusion is presented within the context of the visual attention problem.

De virvelgator som bildas i atmosfären bakom höga berg på öar påminner till utseendet starkt om de periodiska flöden som uppstår vid strömning kring en cirkulär cylinder. Friktionen mellan fluiden och cylinderns yta gör att det bildas en vak nedströms cylindern. Periodisk virvelspridning där von Kármán-virvlar sänds ut kan uppstå. Utifrån Reynolds tal går det att karaktärisera strömningen och med hjälp av en numerisk modell kan tillstånden simuleras. Saknas en turbulensmodell i algoritmen blir resultaten för höga Reynolds tal felaktiga. De atmosfäriska virvelgatorna uppstår dock inte på grund av friktion. Istället krävs blockering av luftmassor och variationer i densitet för att virvlarna ska utvecklas. För att dra slutsatser om de atmosfäriska virvelgatorna har 11 satellitbilder med virvelgator analyserats. Sambandet λ = 3.9b-5.3 (förklaringsgrad r2 = 0.91) hittades mellan virvelgatans våglängd λ och bredden b på ön. Kvoten λ/b beräknades till medelvärdet 4.33 vilket är jämförbart med resultat från en liknande studie. / The visual appearance of the atmospheric vortex street behind a high mountain on an island is very similar to the periodic pattern caused by the flow past a circular cylinder. The friction between the fluid and the surface of the cylinder creates a wake downstream of the cylinder and periodic von Kármán vortex shedding occurs. The flow may be characterized by means of the Reynolds number and using a numerical model the different states can be simulated. If the algorithm lacks a turbulence model, the results for high Reynolds numbers will be wrong. The atmospheric vortex streets do not, however, arise due to friction. Instead, blocking of air masses and density variations are needed for the vortices to develop. To be able to draw conclusions about atmospheric vortex streets 11 satellite images showing the vortex streets have been analyzed. The relation λ = 3.9b-5.3 (coefficient of determination r2 = 0.91) was found, where λ is the wavelength of the vortex street and b the width of the island. The mean value of the ratio λ/b is 4.33 which is comparable with results from a similar study.

The aim of this study is to optimise the acquisition and reconstruction for SPECT with 111In- pentetrotide with the iterative reconstruction software OSEMS. For 111In-pentetrotide SPECT, the uptake in the tumour is usually high compared to uptake in normal tissue. It may, however, be difficult to detect small tumours with the SPECT method because of high noise levels and the low spatial resolution. The liver is a common region for somatostatin-positive metastases, and to visually detect small tumours in the liver, as early as possible, is important for an effective treatment of the cancer disease. The study concentrates on the acquired number of projections, the subset size in the OSEM reconstruction and evaluates contrast as a function of noise for a range of OSEM iterations. The raw-data projections are produced using Monte Carlo simulations of an anthropomorphic phantom, including tumours in the liver. Two General Electric (GE) collimators are evaluated, the extended low-energy general-purpose (ELEGP) and the medium energy general-purpose (MEGP) collimator. Three main areas of reconstruction are investigated. First the reconstructions are performed for so called full time scans with the acquisition time used clinically. Also the effect of performing the examination in half-time or with half the injected activity is evaluated with the most optimal settings gained from the full time scans for both collimators. In addition images reconstructed without model-based compensation are also included for comparison. This study is a continuation of a previous study on 111In-pentetrotide SPECT where collimator choice and model-based compensation were evaluated for a cylindrical phantom representing small tumours in liver background. As in the previous study, ELEGP proved to be the better collimator. For ELEGP, the most optimal setting was 30 projection angles and a subset size of 6 projections in the OSEM reconstruction, and for MEGP optimal setting was 60 projections and 4 subsets. The difference between the different collimator settings were, however, rather small but proven significant. For both collimators the half-time scan including model-based compensation was better compared to the full-time reconstructions without model-based compensation.

A new framework for simulating the visual attention system in primates is introduced. The proposed architecture is an abstraction of existing approaches influenced by the work of Koch and Ullman, and Tompa. Each stage of the attentional hierarchy is chosen with consideration for both psychophysics and mathematical optimality. A set of attentional operators are derived that act on basic image channels of intensity, hue and orientation to produce maps representing perceptual importance of each image pixel. The development of such operators is realized within the context of a genetic optimization. The model includes the notion of an information domain where feature maps are transformed to a domain that more closely corresponds to the human visual system. A careful analysis of various issues including feature extraction, density estimation and data fusion is presented within the context of the visual attention problem.

Due to political decisions regarding the Swedish school, public and independent schools booth face the need topromote themselves in the quest for new pupils. This study aims to, from a communications perspective, examine how four selected upper secondary schools address their target audience; the pupils‐to‐be, on their homepages. Additionally, I intend to investigate whether, and if so, how, said addressing can be connected to the different target groups applying to the schools in question. The questions asked in this study regard the way in which the selected schools describe themselves on their homepage; how do they use the textual and visual content to address their audience, and can there be disagreement between the meaning of the text and that of the image? To answer these questions, I use a theoretical base made out of visual communication and semiotic as well as rhetorical analyses. The methodological procedure is a qualitative approach on the matter, allowing me to understand the “what” of the content on the homepages, as well as the “how” it’s being communicated. I have separated the text from the image, analyzing them separately, so that I can make sense of the whole based on what the segments tell me. I’ve come to the conclusion that there seems to be a pattern between the way in which a Swedish upper secondary school address their target group, and which pupils choose to apply to the school. The schools whose applicants have a high median value in their grades tend to refer to academic values in their descriptions, while the schools whose applicants have the lower median value tend to speak more of the world outside the classroom, and refer to such things as connections with companies or the pupils’ interests.

In this thesis we develop algorithms for the processing of textures and images using a ladder-based biorthogonal directional filter bank (DFB). This work is based on the DFB originally proposed by Bamberger and Smith. First we present a novel implementation of this filter bank using ladder structures. This new DFB provides non-trivial FIR perfect reconstruction systems which are computationally very efficient. Furthermore we address the lack of shift-invariance in the DFB by presenting a novel undecimated DFB that preserves the computational simplicity of its maximally decimated counterpart. Finally, we study the use of the DFB in combination with pyramidal structures to form polar-separable image decompositions. Using the proposed filter banks we develop and evaluate algorithms for texture classification, segmentation and synthesis. We perform a comparative study with other image representations and find that the DFB provides some of the best results reported on the data sets used. Using the proposed directional pyramids we adapt wavelet thresholding algorithms. We find that our decompositions provide better edge and contour preservation than the best results reported using the undecimated discrete wavelet transform. Finally, we apply the developed algorithms to the analysis and processing of synthetic aperture radar (SAR) imagery. SAR image analysis is impaired by the presence of speckle noise. Our first objective will be to study the removal of speckle to enhance the visual quality of the image. Additionally, we implement land cover segmentation and classification algorithms taking advantage of the textural characteristics of SAR images. Finally, we propose a model-based SAR image compression algorithm in which the speckle component is separated from the structural features of a scene. The speckle component is captured with a texture model and the scene component is coded with a wavelet coder at very low bit rates. The resulting decompressed images have a better perceptual quality than SAR images compressed without removing speckle.

One of the primary objectives of this thesis was to design fiber/filler/polymer structures for newsprint and in the process develop a greater understanding of fiber/filler/ polymer structures. Five different designed structures were created for study. The designed structures were composed of virgin, hydrosulfite bleached, TMP southern pine, Georgian kaolin clay and various polymers. Five filler levels from 0% to 20% were employed with each of these different structures. Numerous physical tests were used to gather data which would help to develop an understanding for the macroscopic properties of the structures. Paper structures were created and data from bulk physical tests and particle based SEM image analyses were compared. Comparisons were made using a statistical method called Principal Component Analysis (PCA) where the data is grouped and reduced to find data correlations not readily apparent in the raw data.

This thesis makes significant contributions to the object detection problem in computer vision. The object detection problem is, given a digital image of a scene, to detect the relevant object in the image. One technique for performing object detection, called ``active contours,' optimizes a constructed energy that is defined on contours (closed curves) and is tailored to image features. An optimization method can be used to perform the optimization of the energy, and thereby deform an initially placed contour to the relevant object. The typical optimization technique used in almost every active contour paper is evolving the contour by the energy's gradient descent flow, i.e., the steepest descent flow, in order to drive the initial contour to (hopefully) the minimum curve. The problem with this technique is that often times the contour becomes stuck in a sub-optimal and undesirable local minimum of the energy. This problem can be partially attributed to the fact that the gradient flows of these energies make use of only local image and contour information. By local, we mean that in order to evolve a point on the contour, only information local to that point is used. Therefore, in this thesis, we introduce a new class of flows that are global in that the evolution of a point on the contour depends on global information from the entire curve. These flows help avoid a number of problems with traditional flows including helping in avoiding undesirable local minima. We demonstrate practical applications of these flows for the object detection problem, including applications to both image segmentation and visual object tracking.