Immersion Map Research Articles

Implications of data topology for deep generative models

Many deep generative models, such as variational autoencoders (VAEs) and generative adversarial networks (GANs), learn an immersion mapping from a standard normal distribution in a low-dimensional latent space into a higher-dimensional data space. As such, these mappings are only capable of producing simple data topologies, i.e., those equivalent to an immersion of Euclidean space. In this work, we demonstrate the limitations of such latent space generative models when trained on data distributions with non-trivial topologies. We do this by training these models on synthetic image datasets with known topologies (spheres, torii, etc.). We then show how this results in failures of both data generation as well as data interpolation. Next, we compare this behavior to two classes of deep generative models that in principle allow for more complex data topologies. First, we look at chart autoencoders (CAEs), which construct a smooth data manifold from multiple latent space chart mappings. Second, we explore score-based models, e.g., denoising diffusion probabilistic models, which estimate gradients of the data distribution without resorting to an explicit mapping to a latent space. Our results show that these models do demonstrate improved ability over latent space models in modeling data distributions with complex topologies, however, challenges still remain.

Drawing Connections: Designing Situated Links for Immersive Maps

We explore the design of situated visual links in outdoor augmented reality (AR) for connecting miniature buildings on a virtual map to their real-world counterparts. We first distill design criteria from prior work, then conduct two user studies to evaluate a set of proposed link designs to better understand users' preferences for different design choices of the links. In two user studies we evaluated, respectively, a set of link geometries in a virtual environment and a refined AR prototype in two different outdoor environments. The studies reveal that links help in identifying buildings in the environments. Participants prefer straight rather than curved links, simple and thin links to avoid information occlusion, and links and maps aligned with their direction of view. We recommend using a consistent color with a strong contrast to the background color for all links in a scene. To improve visibility, the diameter of links should grow with distance to the viewer and optional animated stripes can be placed on links. The findings of this study have the potential to bolster the development of various situated visualization applications, such as those used in urban planning, tourism, smart agriculture, and other fields.

Embodied gesture interaction for immersive maps

ABSTRACT With the increasing availability of head-mounted displays for virtual reality and augmented reality, we can create immersive maps in which the user is closer to the data. Embodiment is a key concept, allowing the user to act upon virtual objects in an immersive environment. Our work explores the use of embodied interaction for immersive maps. We propose four design considerations for embodied maps and embodied gesture interaction with immersive maps: object presence, consistent physics, human body skills, and direct manipulation. We present an example of an immersive flow map with a series of novel embodied gesture interactions, which adhere to the proposed design considerations. The embodied interactions allow users to directly manipulate immersive flow maps and explore origin-destination flow data in novel ways. Authors of immersive maps can use the four proposed design considerations for creating embodied gesture interactions. The discussed example interactions apply to diverse types of immersive maps and will hopefully incite others to invent more embodied interactions for immersive maps.

Delineation of the Arm Blood Vessels Utilizing Hyperspectral Imaging to Assist with Phlebotomy for Exploiting the Cutaneous Tissue Oxygen Concentration.

The estimation of tissue oxygenation is vital in the diagnosis and therapeutic evaluation of a huge assortment of diseases. The hyperspectral (HS) imaging system is a rising innovation that can be utilized to build a highly sensitive, non-invasive, and tissue hemoglobin immersion map. As a result of the urgent need to design and implement early detection devices and applications for the COVID-19 pandemic, we propose building a non-invasive custom optical imaging system to assist with phlebotomy and vascular approach to survey the reliability of blood oxygen saturation (SpO2) levels recovered from spectral images. HS images were gathered from 15 healthy subjects without previous medical history complications and with an average age range of 20 to 38 years, who were undergoing phlebotomy. The forearm was vigorously illuminated utilizing an HS camera with polychromatic source light of spectrum range (400∼980 nm). Spectroscopic reflectance images were caught by a focal plane exhibit for the region of interest (ROI). Then the custom algorithm comprising normalization and moving average filtering for noise removal was applied, followed by K-mean clustering for image segmentation to visualize and highlight the arteries and the veins in the investigated forearm. The investigations show that after normalization of the recorded signal from the HS camera of the participating subjects it was noticed that at wavelength of 460 nm the oxygenated arteries had a stronger signal than the de-oxygenated veins, and at a wavelength of 750 nm the de-oxygenated veins had a stronger signal than the oxygenated arteries. Thus, the ideal wavelength to reveal the oxygenated arteries was 460 nm, and the ideal wavelength to reveal the de-oxygenated veins was 750 nm. HSI is a prospective technique to assist with phlebotomy and non-contact oxygen saturation approach. Additionally, it may permit future surgical or pharmacological intercessions that titrate or limit ischemic injury continuously.

Elicitation study investigating hand and foot gesture interaction for immersive maps in augmented reality

ABSTRACTImmersive maps in augmented reality (AR) are virtual maps that plausibly blend with the physical environment, such that the user perceives them as a part of the real world. While immersive maps can offer unprecedented engaging experiences, the way to perform panning, zooming and other basic map interaction is not obvious. This limitation may hamper widespread adoption of immersive maps. We therefore conducted an elicitation study to identify commonly suggested hand and foot gestures for interacting with large immersive AR maps placed on the floor. Study participants were shown simulations of interaction operations, and asked to design gestures to trigger these operations. We selected interaction with hand gestures because they are natural and familiar from interacting with touchscreens. Foot gestures were included because the users’ feet touch immersive maps placed on the floor. Eighteen participants designed hand and foot gestures for panning, rotating, zooming, changing the height of the map, creating a point marker, and selecting a point marker. The most agreed-on hand gesture was for zooming, consisting of grabbing with both hands, then separating or bringing the hands together. Our study participants suggested numerous other inspirational hand and foot gestures, which can guide the further development of interactive immersive maps. Because user preference does not necessarily align with performance, it is important to evaluate the efficiency, accuracy, ease of learning, and physical fatigue for these gestures in follow-up studies.

The influence of user characteristics on spatial perception differences in 3D visual environments

The influence of user characteristics on spatial perception differences in 3D visual environments

Activo distribution and paraphernalia among “street children”

Introduction. The use of solvent inhalants has been documented in Mexico since the 1970s. Nevertheless, very little is known about the distribution and use dynamics among “street children”. Few have ventured to study this issue because of the difficulties involved in working with marginalized, relatively inaccessible populations. Objective. To analyze the distribution and consumption dynamics of activo, as it is known among street children in downtown Mexico City, and to document the paraphernalia and argot associated with these practices. Method. This is a qualitative, descriptive, and interpretative study guided by the “Meeting Place” approach used by Hughes (1977), which has been adapted to Mexican population by Ortiz (1979). We also used ethnographic observation techniques and a social and immersion mapping of street spaces that allowed us to contact and relate to both informants and users. Results. We identified activo distributors and storage areas; user groups were made up of men and women in a 7-3 ratio; physical and psycho-social characteristics of sellers and users, and some street argot and paraphernalia that allowed us to understand the dynamics of distribution and consumption. Discussion and conclusion. The activo market is both captive and hidden; it is detrimental to the physical and mental health of street children, and is fostered by social exclusion and the lack of legislation.

Nature at a glance: Immersive maps from panoramic to digital

This article offers a media archaeology of immersive world maps and astronomical models, focusing on walk-in terrestrial and celestial globes. Innovations in digitally interactive data visualization promise spectators new ways of extracting knowledge from complex information. But the outsized claims and expanded formats of emergent displays invoke the ambitions of earlier scientific spectacles such as the nineteenth-century Georama – a giant sphere whose interior was painted to model the surface of the globe. Comparing immersive and interactive models of earth and sky exposes changing assumptions about how nature is ordered, how aesthetic representation should recapitulate that order, and how a spectator might perceive and know not just a model but the construct of reality itself. This article discusses examples spanning almost two centuries, such as the Gottorp Globe, the Georama, Wyld’s Great Globe, the Celestial Globe of the 1900 Paris Exposition, the Atwood Sphere, the twin maps of Google Earth and Google Sky, and the Reality Deck 1.5 gigapixel display recently funded by the National Science Foundation at Stony Brook University.

Digital stabilization of strict feedback dynamics through immersion and invariance

This paper deals with the extension to sampled-data stabilization of strict feedback dynamics of the Immersion and Invariance procedure proposed in Astolfi and Ortega [2003]. A direct digital approach is developed in two steps: first the target dynamics and immersion mapping are defined for the equivalent discrete-time model; then the control law is built to drive the dynamics towards the invariant manifold. A simulated example illustrates the performances.

On the equivalence of two nonlinear control approaches: Immersion and invariance and IDA-PBC

In this paper we compare the two well-known nonlinear control design techniques Interconnection and Damping Assignment Passivity Based Control (IDA-PBC) and Immersion and Invariance (I&I) at the example of the so-called Acrobot underactuated mechanical system. The immersion and matching equations in both approaches have a similar structure which is exploited to derive equivalent control laws, each of them providing a different perspective on the stabilization problem. In particular, the coordinate change which renders the potential energy matching PDE in IDA-PBC an ordinary differential equation is used to define the immersion map in I&I. It is shown that the energy shaping part of the IDA-PBC controller makes the closed-loop system an interconnection of two lower-dimensional port-Hamiltonian (pH) systems in the on- and off-manifold coordinates that appear in the I&I framework. The effect of damping injection output feedback can be identified with dissipation in the off-manifold part of the interconnected system. Dissipation is propagated to the on-manifold part which results in asymptotic stability of the system's equilibrium. The particular choice of the I&I design parameters in the present example, including the unconventional definition of coordinates on the invariant manifold, provides an interesting re-interpretation of the IDA-PBC control law from the I&I perspective. Finally, a discussion on the equivalence of the two approaches is presented by examining the cases of linear mechanical systems with one unactuated pivot as well as of general linear mechanical systems.

Equivalence of Immersion and Invariance and IDA-PBC for the Acrobot

In this note the two well known nonlinear control design techniques Interconnection and Damping Assignment Passivity Based Control (IDA-PBC) and Immersion and Invariance (I&I) are compared through the example of the so-called Acrobot underactuated mechanical system. Equivalences of both procedures become obvious from the corresponding immersion and matching equations. In particular, the coordinate change which renders the potential energy matching PDE in IDA-PBC an ordinary differential equation is used to define the immersion map in I&I. It is shown that the energy shaping part of the IDA-PBC controller makes the closed-loop system an interconnection of two lower-dimensional port-Hamiltonian (pH) systems in the on- and off-manifold coordinates. The effect of damping injection output feedback can be identified with dissipation in the off-manifold part of the interconnected system. Dissipation is propagated to the on-manifold part which results in asymptotic stability of the system's equilibrium. The analysis in the present work provides an interesting interpretation of the effect of the IDA-PBC control law using the I&I framework.

CLASSICAL TENSORS AND QUANTUM ENTANGLEMENT I: PURE STATES

The geometrical description of a Hilbert space associated with a quantum system considers a Hermitian tensor to describe the scalar inner product of vectors which are now described by vector fields. The real part of this tensor represents a flat Riemannian metric tensor while the imaginary part represents a symplectic two-form. The immersion of classical manifolds in the complex projective space associated with the Hilbert space allows to pull-back tensor fields related to previous ones, via the immersion map. This makes available, on these selected manifolds of states, methods of usual Riemannian and symplectic geometry. Here, we consider these pulled-back tensor fields when the immersed submanifold contains separable states or entangled states. Geometrical tensors are shown to encode some properties of these states. These results are not unrelated with criteria already available in the literature. We explicitly deal with some of these relations.

Immersion of discrete-time nonlinear system by regular dynamic state feedback into a linear system

Necessary and sufficient conditions for local solvability of the title problem around a given trajectory are obtained. The proposed conditions are less restrictive than those obtained by Lee and Marcus for the problem of immersion a nonlinear system into a linear system via static state feedback. Instrumental in the problem solution is the inversion (structure) algorithm for a discrete-time nonlinear system. The solvability conditions are expressed in terms of the inversion algorithm. Moreover, the construction of both the dynamic state feedback and the immersion map relies on this algorithm. Finally, it is shown that, for locally right-invertible systems, the considered problem, unlike the problem of immersion via static state feedback, is always solvable.