Saudi Cultural Missions Theses & Dissertations
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Item Restricted IN-LABORATORY SIMPLIFIED IMAGE-BASED EMPIRICAL POLARIMETRIC BIDIRECTIONAL REFLECTANCE DISTRIBUTION FUNCTION MEASUREMENT USING 3D GEOMETRIC TARGETS(University of Dayton, 2024-04-21) Aldkeelalah, Sultan; Ratliff, BradleyThe bidirectional reflectance distribution function (BRDF) is essential to remote sensing, computer graphics, and material science applications. It aids the development of photo-realistic rendering models, target detection and recognition, and atmospheric characterization tasks in remote sensing. BRDF measurements are cumbersome to make, requiring dense, full hemispherical sampling that often results in millions of individual measurements conducted at precise sensor and illumination source geometries. Methods have been proposed based upon theoretical, experimental, and empirical approaches that aim to simplify the data collection process. Empirically, researchers have proposed using targets of different geometric shapes in conjunction with image-based sensors to acquire measurements in parallel, thus reducing the acquisition time. This work surveys studies of such proposed methods to measure BRDF/polarimetric BRDF (pBRDF). Our group previously presented a fast and simple framework for empirically measuring the pBRDF using a linear imaging polarimeter from novel 3D-printed geodesic target spheres with well-characterized surface facets under outdoor environmental conditions. The models derived from this approach were validated against physics-based models and demonstrated good agreement. In this work, we present a modified approach to conduct similar measurements on the same faceted objects in a laboratory environment. The Applied Sensing Lab at the University of Dayton has constructed a solar simulation laboratory that allows for highly accurate and repeatable positioning of light sources, sensors, and objects. The laboratory contains both collimated (direct sun) and diffuse (downwelling) light sources that we have spectrally tuned in this work to match expected solar irradiance under a range of outdoor conditions. The laboratory-based pBRDF models obtained by our proposed framework validate strongly against their corresponding outdoor, spectroradiometric measurements (ground truth), and physics-based models.27 0Item Restricted Enhancement of User Awareness of Virtual Content in Augmented Reality(Saudi Digital Library, 2023-03-02) Ghazwani, Yahya; Smith, Shamus; Blackmore, KarenAugmented reality (AR) technology combines the virtual and real world by superimposing virtual content onto the real-world environment. A key element that allows the user to view the virtual content combined with the real world is the AR display. While there is a wide variety of AR displays such as hand-held displays, projection-based displays, and head-mounted displays, the AR display field of view is limited compared to the typical human vision field of view. Consequently, the AR user can only perceive and interact with the virtual content through a limited view window. To address this problem, this research project has developed and evaluated the use of different AR notification alerts to enhance the AR user awareness of the virtual content out of their AR display's field of view. The alerts include on-screen AR notifications with both passive and active user interfaces, and 3D register notifications with both passive and active user interfaces. In a user study (n=24), the use of AR on-screen notifications with passive UI has been shown to alert and guide the AR user to virtual content out of their field view faster than the other three configurations. In addition, to validate the use of notifications to enhance the user's limited field of view, a study was conducted (n=46) to evaluate the use of notifications in a collaborative work environment with a limited field of view. The study compared the performance of participants in a collaborative work environment with and without the use of notifications. The study demonstrated that the participants that performed the collaborative tasks with the used notifications completed their task faster and made fewer mistakes than the control group that performed their collaborative task without the use of notifications.36 0