Holographic View Research Articles

Point cloud management for a holographic visualization

Abstract This document aims to describe and verify the workflow from a digital survey of a building of historical value to its set up in an innovative holographic view. Via Lulli is a low-cost building of the beginning of the century organized in a closed-block part of a complex with rather small courtyards; the research topic concerns the verification of the process from acquisition with digital survey to convert the survey dataset into a hologram, considering the huge potential of this display system. Comparison among different point clouds, with different accuracy and dimension are related to the final navigation when transformed in holograms; several tests have been carried out to compare cloud density with the ability to see holograms in details with different zooms in to display small details, and zooms out in real time to view the entire model. First possibility to extend workflow with unity support and other plug-ins are supposed.

Expressway traffic risk intelligent early warning method based on Bayesian network

Expressway traffic hazards often evolve into traffic accidents. Because of the potential traffic risks and system complexity, it is difficult to deal with the real-time expressway traffic risk early warning problem by relying solely on the experience of decision makers and scattered monitoring data. Therefore, it is necessary to study the theory and method of expressway traffic risk early warning by means of data-driven decision-making approach, that is, relying on traffic big data technology to construct a holographic view of expressway traffic status for decision makers, excavating the anomalies hidden behind the data sources, and characterizing traffic accidents. This article focuses on expressway traffic risk intelligent early assessment, using the MATLAB toolbox BNT to establish a Bayesian network for expressway traffic for assessing the risk, discussing the validity and interpretability of the model. The accuracy of the training set and test set is about 0.8902 and 0.8874, respectively, which verifies the model is acceptable and valid. The innovation of this paper is to deal with the problem of expressway traffic risk early warning based on the data-driven perspective, and focuses on the interpretability of the model, giving the expressway decision makers adequate warning information.

Parody and Garden Path

AbstractThis is a study of Chinese rhetorical constructions, parody and garden path (GP), from the perspective of lexico-constructional pragmatics (LCP). LCP adopts a holographic view of lexicon and construction so that they can be analyzed alike. We take parody and GP examples from Chinese advertisements for analysis. The LCP analysis highlights the pragmaticity and rhetoricality of each case: for a particular effect. When difficulty arises, pragmatic means may be used to “pragma-coerce” the right, clever, or erroneous use of a rhetorical construction for delivery of a retrievable intended effect, an Aha-effect. We conduct a mini-questionnaire with two cases, the former dealing with parody and the latter with GP. The study indicates the humor competence of ordinary Chinese participants (around the level of BA) as far as parody and GP are concerned and the participants’ potential for cognition of the pragma-rhetorical values of parody and GP or their potential for generation of such utterances. It is suggested that rhetorical constructions outwit the less rhetorical or grammatical constructionsiffthey are available and accessible, and that LCP can offer us a feasible interpretation of such tropes as parody and GP.

Experimental Visualization of Vascular Structures with Microsoft Hololens – Set-Up for Navigated Contrast Agent and Radiation-Sparing Endovascular Procedures (NAV-CARS EVAR)

Introduction - Over the last two decades, endovascular therapy has become an integral part of vascular surgery. One of the most difficulty in learning and performing this minimally invasive therapy is the fact, the vascular surgeon has to mentally overlay the three-dimensional vascular tree with the two-dimensional angiographic scene. While endovascular techniques are improving, the imaging during the procedure is still dependent on contrast agents and X-Rays with their known disadvantages. Looking at actual development trends towards radiation free localization of endovascular tools, the visualization and proper integration of this spatial information will become a key technology. Methods - We report the development of a real-time navigation software, which allows a three-dimensional view of the vascular system without any need of radiation. We used a vascular phantom model (Blue phantom FAST Trauma Full Torso Ultrasound Training Model) and an augmented reality (AR) headset (Microsoft HoloLens) to display the vascular structures in the field of view of the surgeon. Using simple landmark-based surface registration of a CT scan and marching cubes segmentation of the vessel tree, it is straightforward to visualize both the surface and the vessels in the AR display. Using a magnetic tracking system (i.e. AURORA, Northern Digital Inc.) it is possible to also display the position and orientation of a catheter inside the vessels. Results - Our preliminary results of the virtual real time navigation in endovascular procedures are promising. The presented technique allows a three-dimensional holographic view of the vascular system without any need of radiation. Using extrinsic landmark-based calibrations, the virtual objects are precisely aligned with the real world, resulting in a convincing holographic illusion. The prototype also offers the possibility of intervention planning and simulation, which in turn will lead to a reduced learning curve and therefore increased patient safety. Conclusion - The “virtual angioscope” may improve intraoperative visualization, placement of guide-wires and stents. It may reduce the amount of contrast agents and exposure to X-rays.

Time multiplexing technique of holographic view and Maxwellian view using a liquid lens in the optical see-through head mounted display

We report a liquid lens based optical see-through head mounted display that can simultaneously display both a maxwellian view and a hologram. Holograms are reconstructed by an angular spectrum layer based synthesis method. A hologram and Maxwellian view are simultaneously displayed by focusing the liquid lens from 0 D to 20 D with 60 Hz. The hologram is reconstructed at a position 1.5 m from the eye, and it is confirmed that the Maxwellian view is clear, even if the focus of the eye changes from 50 cm to 1.7 m. In the proposed system, the liquid lens acts as a low-pass filter. Since the PSNR is about 23 dB in the currently used 10 mm diameter liquid lens, the image quality is not adequate. However, we successfully verify the feasibility of our proposed system. In addition, if a large diameter liquid lens of 30 mm or more is applied, excellent image quality of 30 dB or more can be realized.

Towards X-ray free endovascular interventions - using HoloLens for on-line holographic visualisation.

A major challenge during endovascular interventions is visualising the position and orientation of the catheter being inserted. This is typically achieved by intermittent X-ray imaging. Since the radiation exposure to the surgeon is considerable, it is desirable to reduce X-ray exposure to the bare minimum needed. Additionally, transferring two-dimensional (2D) X-ray images to 3D locations is challenging. The authors present the development of a real-time navigation framework, which allows a 3D holographic view of the vascular system without any need of radiation. They extract the patient's surface and vascular tree from pre-operative computed tomography data and register it to the patient using a magnetic tracking system. The system was evaluated on an anthropomorphic full-body phantom by experienced clinicians using a four-point questionnaire. The average score of the system (maximum of 20) was found to be 17.5. The authors’ approach shows great potential to improve the workflow for endovascular procedures, by simultaneously reducing X-ray exposure. It will also improve the learning curve and help novices to more quickly master the required skills.

Holographic view of the senescent cells: Imagine all the senescent cells are not flattened

Holographic view of the senescent cells: Imagine all the senescent cells are not flattened

Evidence for a new model of the human eye ‐ a holographic laser system, biophotonics. The holographic view

PurposeThe authors proposed to verify the eyes structure and function as laser system, position of the image on retina, and properties of bio‐luminescence (BL) of the eye, with help of multidisciplinary studies, biophotonic and bionic tests.MethodsMethods demonstrated that the eyes are laser bifocal systems, with nonlinear medium, through multidisciplinary studies up to date in medicine, biochemistry and physics, original biophotonic tests, delayed luminescence DL, self‐emission SE tests, and two original models of bionic eye.ResultsWe detected: errors of the photographic mechanism of human vision; other properties of human eye as holographic laser system, a laser bifocal system; the eye is initiating BL tract as laser phenomenon, due to internal source of light as phosphate ‐ water; a right position of the images on retina; the amplification of BL along nervous tract, from the eye till to bones and muscles; the BL sense of propagation is reverse nighttime, from brain‐retina‐cornea, show a right position too, as dream; BL properties are: monochromatic, coherent, directionality, rotary polarization, amplified power and information along the nervous system; every color has oscillation plans; nonlinear medium of the cells and organs apply Stokes and anti‐Stokes rule; so it was done the first step for psychic processes (vision, memory, thinking, speech) and bionics.ConclusionsThe eye is a bifocal laser system that initiates a biological laser phenomenon, BL, a coherent monochromatic, polarized and amplified radiation, and renders holograms in right position on retina, due to eye itself, not to brain. Important applications are in medicine, physics, teaching, bionics etc.

Non-equilibrium statistical approach to friction models

A geometric approach to the friction phenomena is presented. It is based on the holographic view which has recently been popular in the theoretical physics community. We see the system in one-dimension-higher space. The heat-producing phenomena are most widely treated by using the non-equilibrium statistical physics. We take 2 models of the earthquake. The dissipative systems are here formulated from the geometric standpoint. The statistical fluctuation is taken into account by using the (generalized) Feynman׳s path-integral.

Aging logarithmic conformal field theory: a holographic view

We consider logarithmic extensions of the correlation and response functions of scalar operators for the systems with aging as well as Schr\"odinger symmetry. Aging is known to be the simplest nonequilibrium phenomena, and its physical significances can be understood by the two-time correlation and response functions. Their logarithmic part is completely fixed by the bulk geometry in terms of the conformal weight of the dual operator and the dual particle number. Motivated by recent experimental realizations of Kardar-Parisi-Zhang universality class in growth phenomena and its subsequent theoretical extension to aging, we investigate our two-time correlation functions out of equilibrium, which show several qualitatively different behaviors depending on the parameters in our theory. They exhibit either growing or aging, i.e. power-law decaying, behaviors for the entire range of our scaling time. Surprisingly, for some parameter ranges, they exhibit growing at early times as well as aging at later times.

Holographic view on quantum correlations and mutual information between disjoint blocks of a quantum critical system

In (d + 1) dimensional Multiscale Entanglement Renormalization Ansatz (MERA) networks, tensors are connected so as to reproduce the discrete, (d + 2) holographic geometry of Anti de Sitter space (AdS d+2) with the original system lying at the boundary. We analyze the MERA renormalization flow that arises when computing the quantum correlations between two disjoint blocks of a quantum critical system, to show that the structure of the causal cones characteristic of MERA, requires a transition between two different regimes attainable by changing the ratio between the size and the separation of the two disjoint blocks. We argue that this transition in the MERA causal developments of the blocks may be easily accounted by an AdS d+2 black hole geometry when the mutual information is computed using the Ryu-Takayanagi formula. As an explicit example, we use a BTZ AdS3 black hole to compute the MI and the quantum correlations between two disjoint intervals of a one dimensional boundary critical system. Our results for this low dimensional system not only show the existence of a phase transition emerging when the conformal four point ratio reaches a critical value but also provide an intuitive entropic argument accounting for the source of this instability. We discuss the robustness of this transition when finite temperature and finite size effects are taken into account.

A Holographic View on Physics out of Equilibrium

We review the recent developments in applying holographic methods to understand nonequilibrium physics in strongly coupled field theories. The emphasis will be on elucidating the relation between evolution of quantum field theories perturbed away from equilibrium and the dual picture of dynamics of classical fields in black hole backgrounds. In particular, we discuss the linear response regime, the hydrodynamic regime, and finally the nonlinear regime of interacting quantum systems. We also describe how the duality might be used to learn some salient aspects of black hole physics in terms of field theory observables.

A Holographic View on Matrix Model of Black Hole

We investigate a deformed matrix model proposed by Kazakov et.al. in relation to Witten's two-dimensional black hole. The existing conjectures assert the equivalence of the two by mapping each to a deformed c=1 theory called the sine-Liouville theory. We point out that the matrix theory in question may be naturally interpreted as a gauged quantum mechanics deformed by insertion of an exponentiated Wilson loop operator, which gives us more direct and holographic map between the two sides. The matrix model in the usual scaling limit must correspond to the bosonic SL(2,R)/U(1) theory in genus expansion but exact in \alpha'. We successfully test this by computing the Wilson loop expectation value and comparing it against the bulk computation. For the latter, we employ the \alpha'-exact geometry proposed by Dijkgraaf, Verlinde, and Verlinde, which was further advocated by Tseytlin. We close with comments on open problems.

Holographic View of Cosmological Perturbations

The cosmological perturbation theory is revisited from the holographic point of view. In the case of the single brane model, it turns out that the AdS/CFT correspondence plays an important role. In the case of the two-brane model, it is shown that the effective equations of motion becomes the quasi-scalar-tensor gravity. It is also demonstrated that the radion anisotropy gives the CMB fluctuations through the Sachs-Wolfe effect.

Brane world effective action at low energies and AdS/CFT correspondence

A low energy iteration scheme to study nonlinear gravity in the brane world is developed. As a result, we obtain the brane world effective action at low energies. The relation between the geometrical approach and the approach using the AdS/CFT correspondence is also clarified. In particular, we find generalized dark radiation as homogeneous solutions in our iteration scheme. Moreover, the precise correspondence between the bulk geometry and the brane effective action is established, which gives a holographic view of the brane world.

Holographic view of causality and locality via branes in AdS/CFT correspondence

We study dynamical aspects of the holographic correspondence between d=5 anti-de Sitter supergravity and d=4 super Yang–Mills theory. We probe causality and locality of ambient space-time from super Yang–Mills theory by studying transmission of low-energy brane waves via an open string stretched between two D3-branes in the Coulomb branch. By analyzing two relevant physical threshold scales, we find that causality and locality is encoded in the super Yang–Mills theory in terms of an infinite tower of long supermultiplet operators. The massive W-boson and dual magnetic monopole behave more properly as extended, bilocal objects. We also study the causal time-delay of a low-energy excitation on a heavy quark or meson and find excellent agreement between the anti-de Sitter supergravity and super Yang–Mills theory descriptions. We observe that the strong 't Hooft coupling dynamics and the holographic scale-size relation thereof play a crucial role to the agreement of dynamical processes.