Deformable Beamsplitters: Enhancing Perception with Wide Field of View, Varifocal Augmented Reality Displays

An augmented reality head-mounted display with full environmental awareness could present data in new ways and provide a new type of experience, allowing seamless transitions between real life and virtual content. However, creating a light-weight, optical see-through display providing both focus support and wide field of view remains a challenge. This dissertation describes a new dynamic optical element, the deformable beamsplitter, and its applications for wide field of view, varifocal, augmented reality displays. Deformable beamsplitters combine a traditional deformable membrane mirror and a beamsplitter into a single element, allowing reflected light to be manipulated by the deforming membrane mirror, while transmitted light remains unchanged. This research enables both single element optical design and correct focus while maintaining a wide field of view, as demonstrated by the description and analysis of two prototype hardware display systems which incorporate deformable beamsplitters. As a user changes the depth of their gaze when looking through these displays, the focus of virtual content can quickly be altered to match the real world by simply modulating air pressure in a chamber behind the deformable beamsplitter; thus ameliorating vergence–accommodation conflict. Two user studies verify the display prototypes’ capabilities and show the potential of the display in enhancing human performance at quickly perceiving visual stimuli. This work shows that near-eye displays built with deformable beamsplitters allow for simple optical designs that enable wide field of view and comfortable viewing experiences with the potential to enhance user perception.Doctor of Philosoph

PHOTONIC STRUCTURES AND DEVICES MOLDED ON SOFT POLYMER MATERIALS

Polymer materials are ubiquitous, relatively cheap, easy to process, and functionalize, making them interesting for many applications, in particular for optical systems that are traditionally fabricated from rigid and expensive materials. Polymer properties can be exploited to modulate the optical response of photonic structures. In this dissertation, I will discuss the fabrication and demonstration of several applications of soft polymers in the field of optics. Soft polymers can be used to fabricate structures with optical effects inaccessible using a single optical element created from standard materials. First, I employed a biomimetic approach to produce structural color similar to the bright blue of the Morpho Butterfly. Second, I used shape active polymers to reversibly modulate the height of an optical grating through heat. Lastly, I developed a varifocal polymer lens for an augmented reality system. Structural Color, as opposed to pigmented color, is the result of light interacting with structures with geometrical length scales comparable with the wavelength of visible light. There are many examples of structural color found in nature, from the various colors of the jewel beetles to the vibrant blue of the kingfisher bird. This structural effect can typically be identified by the iridescent nature of the coloration. I will discuss my approach toward biomimicry of the unique photonic structure found on the surface of the Morpho butterfly wings. This sub-micron sized structure is a ridge which in cross-sectional view resembles a tree, with a thin “trunk” and many periodic “branches” that produce a multilayer interference effect, strongly reflecting a brilliant blue color over a wide angular range. Biomimicry of the Morpho butterfly nanostructure has been attempted but the angular insensitivity has never been fully shown in a man-made replica. I will discuss the importance of the inherent randomness found within the Morpho structures that causes light to spread over such a large range. Here in, I will show two different fabrication approaches to integrate microstructure randomness and the consequence of such variations on the angular response. In structures that were fabricated using interference lithography a quasi-randomness (incomplete randomization) is induced through drying. Angular measurements show that a two-lobe reflection, much alike that produced by the true butterfly wing, is produced in angular space and is attributable to this quasi-random nanostructure. However, periodicity needs to be fully destroyed in order to overcome diffraction. To do this a direct-write lithography system was built and used to produce completely non-periodic structures. The results showed a more pronounced a two-lobe reflection at oblique angles. Finite-difference time-domain (FDTD) simulations were employed to understand this reflection signature and to determine effect of other geometric features. From these simulations a photonic structure, capable of spreading light in similar fashion to the butterfly, and that can be fabricated with standard microfabrication techniques is proposed. In connection to the use of polymers in diffractive structures, I will discuss my work with shape active polymers. Shape memory polymers offer a unique approach for application that demand multipurpose parts and have been utilized as heart stents and actuators. The applicability of these shape memory polymers as optical elements is demonstrated by examining the optical response of a shape shifting diffraction grating. As the height of the diffraction grating is reversibly changed the intensity of diffracted light is modulated. This constitutes a simple device realization that nevertheless illustrates the materials and optical issues that arise from the application of shape memory polymer in more complex photonic shapes will lead to the optical systems with versatile components. Finally, the use of elastomeric polymers as shape active lens will be explored. Varifocal lenses have shown the potential to solve an inherent problem in virtual and augmented reality headsets. In augmented and virtual reality headsets, the human eye will focus on the screen several inches from the face but images for both eyes are off set in order cause the users eyes to converge at a certain angle, imitating distance. In the real-world focus and vergence are in sync but these headsets encounter what is known as vergence–accommodation conflict and it is the source of major user discomfort. Vergence–accommodation conflict prevents the wide spread adoption of these potentially impactful technologies. I will present my work in developing a varifocal half silvered mirror for use in an augmented reality system. The system was validated by a perception test that showed users having increased success when the system was properly focusedDoctor of Philosoph

Personal imaging

Thesis (Ph.D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts & Sciences, 1997.Includes bibliographical references (p. 217-223).In this thesis, I propose a new synergy between humans and computers, called "Humanistic Intelligence" (HI), and provide a precise definition of this new form of human-computer interaction. I then present a means and apparatus for reducing this principle to practice. The bulk of this thesis concentrates on a specific embodiment of this invention, called Personal Imaging, most notably, a system which I show attains new levels of creativity in photography, defines a new genre of documentary video, and goes beyond digital photography/video to define a new renaissance in imaging, based on simple principles of projective geometry combined with linearity and superposition properties of light. I first present a mathematical theory of imaging which allows the apparatus to measure, to within a single unknown constant, the quantity of light arriving from each direction, to a fixed point in space, using a collection of images taken from a sensor array having a possibly unknown nonlinearity. Within the context of personal imaging, this theory is a contribution in and of itself (in the sense that it was an unsolved problem previously), but when also combined with the proposed apparatus, it allows one to construct environment maps by simply looking around. I then present a new form of connected humanistic intelligence in which individuals can communicate, across boundaries of time and space, using shared environment maps, and the resulting computer-mediated reality that arises out of long-term adaptation in a personal imaging environment. Finally, I present a new philosophical framework for cultural criticism which arises out of a new concept called 'humanistic property'. This new philosophical framework has two axes, a 'reflectionist' axis and a 'diffusionist' axis. In particular, I apply the new framework to personal imaging, thus completing a body of work that lies at the intersection of art, science, and technology.by Steve Mann.Ph.D

Augmented Reality

Augmented Reality (AR) is a natural development from virtual reality (VR), which was developed several decades earlier. AR complements VR in many ways. Due to the advantages of the user being able to see both the real and virtual objects simultaneously, AR is far more intuitive, but it's not completely detached from human factors and other restrictions. AR doesn't consume as much time and effort in the applications because it's not required to construct the entire virtual scene and the environment. In this book, several new and emerging application areas of AR are presented and divided into three sections. The first section contains applications in outdoor and mobile AR, such as construction, restoration, security and surveillance. The second section deals with AR in medical, biological, and human bodies. The third and final section contains a number of new and useful applications in daily living and learning

TOWARDS EFFECTIVE DISPLAYS FOR VIRTUAL AND AUGMENTED REALITY

Virtual and augmented reality (VR and AR) are becoming increasingly accessible and useful nowadays. This dissertation focuses on several aspects of designing effective displays for VR and AR. Compared to conventional desktop displays, VR and AR displays can better engage the human peripheral vision. This provides an opportunity for more information to be perceived. To fully leverage the human visual system, we need to take into account how the human visual system perceives things differently in the periphery than in the fovea. By investigating the relationship of the perception time and eccentricity, we deduce a scaling function which facilitates content in the far periphery to be perceived as efficiently as in the central vision. AR overlays additional information on the real environment. This is useful in a number of fields, including surgery, where time-critical information is key. We present our medical AR system that visualizes the occluded catheter in the external ventricular drainage (EVD) procedure. We develop an accurate and efficient catheter tracking method that requires minimal changes to the existing medical equipment. The AR display projects a virtual image of the catheter overlaid on the occluded real catheter to depict its real-time position. Our system can make the risky EVD procedure much safer. Existing VR and AR displays support a limited number of focal distances, leading to vergence-accommodation conflict. Holographic displays can address this issue. In this dissertation, we explore the design and development of nanophotonic phased array (NPA) as a special class of holographic displays. NPAs have the advantage of being compact and support very high refresh rates. However, the use of the thermo-optic effect for phase modulation renders them susceptible to the thermal proximity effect. We study how the proximity effect impacts the images formed on NPAs. We then propose several novel algorithms to compensate for the thermal proximity effect on NPAs and compare their effectiveness and computational efficiency. Computer-generated holography (CGH) has traditionally focused on 2D images and 3D images in the form of meshes and point clouds. However, volumetric data can also benefit from CGH. One of the challenges in the use of volumetric data sources in CGH is the computational complexity needed to calculate the holograms of volumetric data. We propose a new method that achieves a significant speedup compared to existing holographic volume rendering methods

Experimental Quantum Communication with GNSS satellites

Quantum Communication (QC) is referred as all those protocols that deal with the faithful transportation of quantum states. The huge technological progress in the manipulation of the single quantum particles has led to the experimental tests of some of the most intriguing features of Quantum Mechanics (QM). The gedankenexperiments that were formulated by the fathers of QM in the last century, have become real. In the words of Schrödinger: “... we never experiment with just one electron or atom or (small) molecule.” This is no longer true. We can do experiments involving single atoms or molecules and even single photons, and thus it becomes possible to demonstrate that the “ridiculous consequences” alluded to by Schrödinger are, in fact, quite real. The possibility of preparing, manipulating and detecting single photons has paved the way for the field of QC . Many interesting applications related to the security of communication start taking shape, of which the most promising is the Quantum Key Distribution ( QKD ). The crucial step towards the establishment of these quantum technologies is the extension of the communication channel up to the possibility of connecting any two points around the Earth. To this aim, two main strategies are being pursued: the development of quantum repeaters in order to interconnect several fiber-based channels, each of which have limited extension due to the inherent losses of the fiber, and the progress of satellite-to-ground and satellite-to-satellite links that take advantage of the lower losses of the free-space channel. This thesis collects my research under the supervision of Prof. Giuseppe Vallone and Prof. Paolo Villoresi on a set of topics in the quantum communication science, the main objective being the extension of the satellite-to-ground channel towards MEO and its applications on the fundamental tests of QM . Particular attention have also been dedicated to the applications of weak measurements

Visualization Authoring for Data-driven Storytelling

Data-driven storytelling is the process of communicating insights and findings that are supported by data, forming a visualization-based narrative. However, most current visualization creation tools either only support fixed sets of designs or require an in-depth understanding of programming concepts. To enable non-programmers to create custom visualizations for data-driven storytelling, we design interactions and implement user interfaces for visualization authoring. In the first part of this dissertation, we introduce and evaluate a series of three visualization authoring tools using traditional user interfaces: (1) iVisDesigner, which uses a data-flow model and enables users to author visualizations by specifying mappings from data to graphics interactively; (2) ChartAccent, a tool for annotating a given visualization; and (3) Charticulator, which allows users to design custom layouts interactively. We then reflect on the evaluation of visualization authoring user interfaces. In the second part of the dissertation, we extend our approach to multiple presentation media or display environments, including traditional 2-dimensional screens, large projection-based virtual-reality (VR) systems, and head-mounted virtual/augmented reality displays (HMDs). To leverage such immersive visualization environments, we ported and extended the iVisDesigner authoring approach to projection-based virtual reality. To facilitate the development of immersive visualizations, we built a visualization library called Stardust, which provides a familiar API to utilize GPU processing power in a cross-platform way. Finally, we present Idyll-MR, a system for authoring data-driven stories in virtual and augmented reality. We evaluated these authoring tools and libraries, and demonstrated high expressiveness, usability, and performance, as well as portability across platforms. In summary, our contributions enable larger audiences to create visual data-driven stories using different presentation media, leading to an overall enriched diversity of visualization designs

Untersuchungen zu nutzerbezogenen und technischen Aspekten beim Langzeiteinsatz mobiler Augmented Reality Systeme in industriellen Anwendungen

Magdeburg, Univ., Fak. für Informatik, Diss., 2009Johannes Tümle