A common metaphor for visual attention is the spotlight (Posner, 1980). It follows from the spotlight metaphor and other similar models (e.g., zoom-lens model; Eriksen and Yeh, 1985) that attention can, according to task-demands, be constricted into a focused beam (i.e., analogous to selective attention) or dilated to encompass a larger breadth (i.e., analogous to divided attention). It is currently unclear how variations in perceptual load of a display affect the FFOV. Lavie (1995; Lavie et al., 2004) proposed that the critical determinant of selective attention (i.e., a constriction of the FFOV) was the perceptual load imposed by the taskselective attention is a necessary outcome of limited perceptual processing capacity. Age-related differences in perceptual processing capacity (e.g., Maylor and Lavie, 1998) may then explain observed age-related differences in FFOV size (e.g., Ball, Beard, Roenker, Miller, and Griggs, 1988). The current study examined how perceptual load and aging affected the FFOV. Younger and older participants viewed brief displays in which they engaged in two tasks: the first task was a perceptual load manipulation, while the second task was a measure of the FFOV. Multiple measures of peripheral task performance suggest that the size of the FFOV for older adults was significantly reduced by increasing perceptual load and this effect of load was greater with increasing distance from fixation. As predicted from the perceptual load model, when perceptual load of the task increased, perceptual sensitivity for the distant peripheral task decreased for older adults. This decrease was greater when the task was farther from fixationindicative of a shrinking spotlight. However, for younger adults, increasing load did not affect peripheral task performance. This age-related difference may be attributable to older adults reduced perceptual processing capacity. The current results support the notion that older adults reduced perceptual processing capacity may be one cause of their reduced FFOV. Limitations of the current study as well as future research are discussed.

Astronomy large-scale surveys require instrumentation to minimize the time required to complete observations of large sections of the sky. Optimizing receiver systems has been achieved through reducing the system temperature primarily by advances in low-noise amplifier technology to a point that the internally generated noise is now fast approaching the quantum limit. Instead, reflector-coupled focal plane arrays are now used to increase the field of view (FoV) by employing either multi-element horn feeds or phased array feeds. Widely spaced (2-3 wavelengths diameter) horn feeds inefficiently sample the available focal plane radiation, thus requiring multiple imaging passes. Alternatively, a more efficient method is to use a narrow element (0.5 wavelengths diameter) phased array feed with a beamformer to produce overlapping beams on the sky, fully Nyquist sampling the focal plane with a single pass. The FoV can be further increased with additional phased array feed (PAF) antenna-receiver modules adding to the contiguous fully sampled region. A 5 x 5 K-band (18 - 26 GHz) single polarization modular PAF incorporating an antenna array of planar axially symmetric elements is designed, simulated, manufactured and tested. Each narrow width tapered slot antenna element has an independent receiver chain consisting of a cryogenic packaged monolithic microwave integrated circuit (MMIC) GaAs amplifier and a packaged MMIC down converting mixer. Synthesized beams and beamformer characteristics are presented. The PAF imaging system performance is evaluated by survey speed and compared to the industry standard, the single pixel feed (SPF). Scientifically, K-band is attractive because it contains numerous molecular transitions, in particular the rotation-inversion lines of ammonia. These transitions are excited in dense gas, and can be used to directly measure kinetic temperatures and velocities of protostars throughout the Galaxy. Depending on the line detected, gas of different temperatures can be probed. It is concluded that even with a higher system temperature, a PAF with sufficient number of synthesized beams can outperform a SPF in imaging speed by more than an order of magnitude. / Graduate

Field of view in virtual environments such as games is the angular cone-of-vision a camera uses to display content on screen, and is subject to various characteristics and effects. Some of these effects have been documented based on simulation. However little to no research is readily available regarding video games. This paper set out to document and verify if field of view can reliably be used to affect potential game design aspects, particularly for first-person cameras. Several factors were identified and tests constructed which had participants play through a virtual first-person environment on regular computer hardware (no head-mounted display or other viewing mediums). The measured properties were distance, scale and speed as a function of field of view. According to the results, distances appear longer, objects appear smaller and movement faster at higher field of view, however at varying amounts depending on the context, scenario and viewing angle of the camera. In addition it was also shown that text readability and peripheral vision were significantly affected. It was concluded that field of view can be used within games and virtual applications to enable certain game design elements, and that field of view also should be a consideration in designing a game as it may be interpreted differently given a different field of view.

Výpočetní tomografie je nástroj pro nedestruktivní inspekci vzorků, který je běžně používán v mnoha oblastech průmyslu a výzkumu. Některé tomografické přístroje umožňují snímání obrazů s prostorovým rozlišením pod jeden mikrometr. Zorné pole takovýchto přístrojů bývá malé, v rozsahu jednotek milimetrů či méně. Tím jsou omezeny rozměry vzorků, což je značně limitující. Toto omezení lze překonat pomocí různých technik pro rozšíření zorného pole. Jedna takováto dříve publikovaná metoda byla v této práci upravena a implementována pro přístroj Rigaku Nano3DX. Tato technika téměř zdvojnásobuje zorné pole přístroje bez nutnosti většího detektoru. Implementovaný přístup byl testován pomocí umělých i skutečných dat, a jeho účinnost byla zhodnocena subjektivně i objektivně, pomocí vizuální kontroly a metrik kvality obrazu. Hodnocení je převážně založeno na srovnání obrazů rekonstruovaných pomocí této metody s obrazy získanými pomocí většího detektoru. Implementovaná technika rozšíření zorného pole poskytuje věrné rekonstrukce vzorku, srovnatelné se zmíněnými protějšky.

Tidigare forskning har visat att bilförare tenderade att underskatta hastigheten de färdas i med ca 20%. Forskning har även visat att hastighetsupplevelse hos bilförare kan påverkas av ett utökat Field of View (FoV) vilket resulterar i lägre hastighetsval (Pretto et al., 2009; Schütz et al., 2015; Lidestam, Eriksson & Eriksson, 2019). Utöver FoV har även virtuella vägmarkeringar (VRM), visats ha potentialen att påverka hastighetsval genom att bistå bilförare med ytterliggare visuell information kring dennes omgivning (Lidestam, Eriksson & Eriksson, 2019). Attityder gentemot system som syftar till att påverka bilförares hastighetsval har studerats (Wall et al., 2013), med det finns luckor i forskning gällande hur dessa upplevs av bilförare med ADHD. Vidare har även upprepning av körningar med samma konstellationer av visuella stimuli har visats påverka hastighetsval vilket skulle tyda på perceptuell inlärning sker under bilkörning (Lindestam, Eriksson & Eriksson, 2019). Syftet med den aktuella studien var att undersöka huruvida VRM påverkade hastighetsval samt hur de upplevs av bilförare med respektive utan ADHD. Studien ämnade att göra detta genom att besvara följande frågeställningar 1. a. Hur upplevdes VRM? b. Finns det en skillnad i upplevelsen av VRMs mellan bilförare med ADHD och utan ADHD? 2. Vilken effekt har ADHD, FoV, VRM och replikat på självvald hastighet? Resultaten visade att upplevelsen av VRM inte skiljde sig signifikant mellan de två guppen, trots detta skattades samtliga frågor kring upplevelsen av VRM högre av bilförare med ADHD än bilförare utan ADHD. Körningarna rapporterades som signifikant mer koncentrationskrävande av bilförare utan ADHD. Replikat och FoV uppvisade en signifikant interaktionseffekt på hastighetsval. Framtida forskning kan med fördel studera hur VRM kan utformas för att upplevas som mer hjälpsamma samt hur de bör implementeras för att bilförare ska vilja använda dem vid körningar. Det är viktigt att framtida forskning i området även inkluderar bilförare med ADHD för att säkerställa att system som utformas även är gynnsamma för dessa bilförare.

There has been an increasing interest in visual sensors and vision-based solutions for single and multi-robot systems. Vision-based sensors, e.g., traditional RGB cameras, grant rich semantic information and accurate directional measurements at a relatively low cost; however, such sensors have two major drawbacks. They do not generally provide reliable depth estimates, and typically have a limited field of view. These limitations considerably increase the complexity of controlling multiagent systems. This thesis studies some of the underlying problems in vision-based multiagent control and mapping. The first contribution of this thesis is a method for restoring bearing rigidity in non-rigid networks of robots. We introduce means to determine which bearing measurements can improve bearing rigidity in non-rigid graphs and provide a greedy algorithm that restores rigidity in 2D with a minimum number of added edges. The focus of the second part is on the formation control problem using only bearing measurements. We address the control problem for consensus and formation control through non-smooth Lyapunov functions and differential inclusion. We provide a stability analysis for undirected graphs and investigate the derived controllers for directed graphs. We also introduce a newer notion of bearing persistence for pure bearing-based control in directed graphs. The third part is concerned with the bearing-only visual homing problem with a limited field of view sensor. In essence, this problem is a special case of the formation control problem where there is a single moving agent with fixed neighbors. We introduce a navigational vector field composed of two orthogonal vector fields that converges to the goal position and does not violate the field of view constraints. Our method does not require the landmarks' locations and is robust to the landmarks' tracking loss. The last part of this dissertation considers outlier detection in pose graphs for Structure from Motion (SfM) and Simultaneous Localization and Mapping (SLAM) problems. We propose a method for detecting incorrect orientation measurements before pose graph optimization by checking their geometric consistency in cycles. We use Expectation-Maximization to fine-tune the noise's distribution parameters and propose a new approximate graph inference procedure specifically designed to take advantage of evidence on cycles with better performance than standard approaches. These works will help enable multi-robot systems to overcome visual sensors' limitations in collaborative tasks such as navigation and mapping.

Virtual Reality (VR) and Augmented Reality (AR) Head Mounted Display (HMD) or Head Worn Display (HWD) technology represents low-cost, wide Field of Regard (FOR), deployable systems when compared to traditional simulation facilities. However, given current technological limitations, HWD flight simulator implementations provide a limited effective Field of View (eFOV) far narrower than the normal human 200[degrees] horizontal and 135[degrees] vertical FOV. Developing a HWD with such a wide FOV is expensive but can increase the aviator's visual stimulus, perception, sense of presence and overall training effectiveness. This research and experimentation test this proposition by manipulating the eFOV of experienced pilots in a flight simulator while measuring their reflexive motor response and task performance. Reflexive motor responses are categorized as information, importance and effort behaviors. Performance metrics taken include runway alignment error (RAE) and vertical track error (VTE). Results indicated a significant and systematic change in visual scan pattern, head movement and flight control performance as the eFOV was sequentially decreased. As FOV decreased, the average visual scan pattern changed to focus less on out-the-window (OTW) and more on the instruments inside the cockpit. The head range of movement significantly increased below 80[degrees] horizontal x 54[degrees] vertical eFOV as well as significantly decreasing runway alignment and vertical track performance, which occurred below 120[degrees] horizontal x 81[degrees] vertical eFOV.

In remote or teleoperational tasks involving humans and robots, various aspects of the remote display system may greatly influence the individual's interactions with the teleoperated entity. This dissertation examined various configurations of display systems on several measures of operator performance, physiological states, and perceptions of the task. Display configurations included altering the camera placement (attached to the robot or placed overhead), screen orientation (horizontal or vertical), and screen size (small or large). Performance was measured in terms of specific task goals, accuracies, strategies, and completion times. Physiological state was assessed through physiological markers of arousal, specifically heart rate and skin conductance. Operator perception of the task was measured with a self-reported perception of workload and frustration. Scale model live simulation was used to create a task driven environment to test the display configurations. Screen size influenced performance on complex tasks in mixed ways. Participants using a small screen exhibited better problem solving strategies in a complex driving task. However, participants using the large screen exhibited better driving precision when the task required continual attention. These findings have value in design decisions for teleoperated interfaces where the advantages and disadvantages of screen size must be considered carefully. Orientation of the visual information seems to have much less impact on the operator than the source of the information, though it was an important factor of the display system when taken together with screen size and camera view. Results show strong influence of camera placement on many of the performance variables. Interestingly, the participants rated a higher frustration in the overhead condition, but not a higher task load, indicating that while they realized that the task was frustrating and perhaps they could have done better, they did not recognize the task as overloading. This was the case even though they took longer to complete the task and experienced more errors related to turning in the overhead camera condition. This finding may indicate a potential danger for systems in which the operator is expected to recognize when he or she is being overloaded. This type of performance decrease due to added frames of reference may be too subtle to register in the operator's self awareness

Wide-field photometry is prone to various degradations, such as atmospheric ex- tinction, varying point spread functions, and aliasing in addition to classical noise sources such as photon, sky background, readout, and thermal noise. While space- borne observations do not suer from atmospheric eects, varying star images over a large sensor and aliasing may seriously impede good results. A measure of the achievable precision of ground-based dierential photometry with the prototype photometer for the BRITE satellite mission is reported, using real sky observa- tions. The data were obtained with the photometer attached to a paramount tracking platform, using the Image Reduction and Analysis Facility Software (IRAF) image reduction and analysis methods as well as the author's own Matlab Code. Special emphasis is placed on the analysis of varying apertures for vary- ing point spread functions, which shows that the accuracy can be improved by taking into account the statistics for each star instead of using a xed aperture. In addition a function is dened, which describes the expected error in terms of instrumental magnitudes, taking into account Poisson distributed noise and mag- nitude independent noise, mainly aliasing. This function is then t to observed data in a two-dimensional least squares sense, providing a calculated aliasing error of 7 millimagnitudes. This function is furthermore rewritten in terms of the stan- dard magnitude B. A maximum magnitude can then be determined for a certain precision, which shows that the Bright Target Explorer (BRITE) can reach a pho- tometric error of 1 millimagnitude for stars with magnitude B &lt; 3:5, assuming the worst case duty cycle of 15 minutes. / <p>Validerat; 20110211 (anonymous)</p>

Virtual reality (VR) head-mounted displays provide a high definition, immersive experi-ence to the viewer. However, most existing technologies have flaws like bulky design and vergence-accommodation conflict that may cause stress in the neck muscles, posture issues, nausea, motion sickness and dizziness. Similarly, augmented reality (AR) displays, which use transparent light modulators, exist, but they possess low field of view and a limited number of discrete depth planes when wide field of view and continuous depth would be ideal. The ultimate goal of my research is use leaky mode waveguide devices to create wide-view angle, transparent near eye holographic displays for AR with strong continuous depth accommo-dation and no vergence-accommodation conflict. The leaky mode platform has the advantages of low fabrication complexity and monolithic design. Unfortunately, bottom-exit leaky mode devices to date have had produced relatively small view angles. The specific objective of this thesis is to explore the use of static structures in leaky mode waveguide devices to increase field of view. In this work I will show that it is theoretically possible to achieve increased field of view with increased resolution and no overlap among view zones. My specific contributions to this research include: i) modeling of integrated Lithium Nio-bate device and testrig that contains quartz substrates on MATLAB, ii) construction of a simulator of the integrated device which involved fabrication of a prototype test rig for intermediate laser induced structures, iii) fabrication of intermediate diffractive structures by photolithography and by femto-second laser ablation which involved - 100 sample test, dose test and creation of sample femtograting on Lithium Niobate substrate. Results which are obtained from the modelling of inte-grated device and the prototype simulator are analysed. This analysis is provided in my manuscript to show how precise is the prototype simulator when compared with integrated device. The ob-tained result of the integrated device is 52.4541° where as it is 69.113° for prototype simulator. This effort was reported in a publication and presentation at Brigham Young University, Provo, Utah.