wavefront
Wavefront Coding for Accommodation-Invariant Near-Eye Displays
Akpinar, Ugur, Sahin, Erdem, Hayward, Tina M., Majumder, Apratim, Menon, Rajesh, Gotchev, Atanas
Abstract--We present a new computational near-eye display method that addresses the vergence-accommodation conflict problem in stereoscopic displays through accommodation-invariance. We employ end-to-end learning to jointly optimize the wavefront-coding optics and the image pre-processing module. T o implement this approach, we develop a differentiable retinal image formation model that accounts for limiting aperture and chromatic aberrations introduced by the eye optics. We further integrate the neural transfer function and the contrast sensitivity function into the loss model to account for related perceptual effects. T o tackle off-axis distortions, we incorporate position dependency into the pre-processing module. In addition to conducting rigorous analysis based on simulations, we also fabricate the designed diffractive optical element and build a benchtop setup, demonstrating accommodation-invariance for depth ranges of up to four diopters. HE simplicity of stereoscopic near-eye display (NED) design has made these systems particularly attractive for virtual reality (VR) and augmented reality (AR) applications. However, a major drawback hindering their widespread adoption is the vergence-accommodation conflict (V AC), which is caused by the mismatch between the two visual cues. In natural viewing conditions, vergence and accommodation work in synchrony, but the link between them gets broken in stereoscopic NEDs, resulting in severe visual discomfort [1], [2], [3]. Two groups of methods have addressed the V AC. Accommodation-enabling (AE) displays have aimed at delivering close-to-natural viewing experience by recreating near-correct retinal blur to drive the accommodation to the vergence distance of the object. We discuss AE display approaches in more details in Sec. Instead of recreating focus cues, accommodation-invariant (AI) displays have aimed at coupling vergence with accommodation by removing the retinal defocus blur completely.
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- Asia > South Korea > Gyeongsangnam-do > Changwon (0.04)
- North America > United States > Utah > Salt Lake County > Salt Lake City (0.04)
- Europe > Netherlands > North Holland > Amsterdam (0.04)
- Health & Medicine > Therapeutic Area > Ophthalmology/Optometry (1.00)
- Health & Medicine > Diagnostic Medicine > Imaging (0.88)
Inverse Synthetic Aperture Fourier Ptychography
Chan, Matthew A., Pellizzari, Casey J., Metzler, Christopher A.
Fourier ptychography (FP) is a powerful light-based synthetic aperture imaging technique that allows one to reconstruct a high-resolution, wide field-of-view image by computationally integrating a diverse collection of low-resolution, far-field measurements. Typically, FP measurement diversity is introduced by changing the angle of the illumination or the position of the camera; either approach results in sampling different portions of the target's spatial frequency content, but both approaches introduce substantial costs and complexity to the acquisition process. In this work, we introduce Inverse Synthetic Aperture Fourier Ptychography, a novel approach to FP that foregoes changing the illumination angle or camera position and instead generates measurement diversity through target motion. Critically, we also introduce a novel learning-based method for estimating k-space coordinates from dual plane intensity measurements, thereby enabling synthetic aperture imaging without knowing the rotation of the target. We experimentally validate our method in simulation and on a tabletop optical system.
- North America > United States > Maryland > Prince George's County > College Park (0.14)
- North America > United States > Florida > Miami-Dade County > Miami (0.04)
- North America > United States > Colorado > Boulder County > Boulder (0.04)
- Government > Military (0.94)
- Government > Regional Government > North America Government > United States Government (0.93)
- Media (0.74)
Traversability-aware path planning in dynamic environments
Marchukov, Yaroslav, Montano, Luis
Planning in environments with moving obstacles remains a significant challenge in robotics. While many works focus on navigation and path planning in obstacle-dense spaces, traversing such congested regions is often avoidable by selecting alternative routes. This paper presents Traversability-aware FMM ( Tr-FMM), a path planning method that computes paths in dynamic environments, avoiding crowded regions. The method operates in two steps: first, it dis-cretizes the environment, identifying regions and their distribution; second, it evaluates the traversability of regions, aiming to minimize both obstacle risks and goal deviation. The path is then computed by propagating the wavefront through regions with higher traversability. Simulated and real-world experiments demonstrate that the approach ensures significant safety by keeping the robot away from obstacles while minimizing excessive goal deviations. Introduction Robots operating without direct human supervision or intervention in everyday life are becoming increasingly common. Consequently, moving in spaces shared with humans emerged as a significant challenge in robotics [1]. Typical examples of such environments include indoor settings like stores, warehouses, and airports [2]. In these crowded or busy environments, people often move unpredictably or without paying sufficient attention to robots, potentially leading to collisions or deadlock situations from which a robot cannot recover [3]. Therefore, it is crucial that robots are capable of avoiding such situations, where people are seen as dynamic obstacles needed to be avoided. Classic and widely used navigation techniques, such as DW A [4] and elastic bands [5], struggle in the aforementioned situations. DW A is designed for static scenarios, while elastic bands are not suited for highly dynamic and crowded environments. Navigation methods that account for dynamic obstacles, such as VO [6], RVO [7], and ORCA [8], are designed as local planners for maneuvering among people or moving obstacles, rather than as global planners for such scenarios. More recent approaches, often based on advanced learning techniques [9][10][11], demonstrate higher success rates in avoiding collisions. All these techniques are most useful when the robot is already inside a crowd or has no choice but to pass through one, accepting the potential risk of collision.
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- Europe > Spain > Aragón > Zaragoza Province > Zaragoza (0.04)
- Asia > Middle East > Republic of Türkiye > Karaman Province > Karaman (0.04)
Multi-agent coordination for on-demand data gathering with periodic information upload
Marchukov, Yaroslav, Montano, Luis
In this paper we develop a method for planning and coordinating a multi-agent team deployment to periodically gather information on demand. A static operation center (OC) periodically requests information from changing goal locations. The objective is to gather data in the goals and to deliver it to the OC, balancing the refreshing time and the total number of information packages. The system automatically splits the team in two roles: workers to gather data, or collectors to retransmit the data to the OC. The proposed three step method: 1) finds out the best area partition for the workers; 2) obtains the best balance between workers and collectors, and with whom the workers must to communicate, a collector or the OC; 3) computes the best tour for the workers to visit the goals and deliver them to the OC or to a collector in movement. The method is tested in simulations in different scenarios, providing the best area partition algorithm and the best balance between collectors and workers.
- North America > United States (0.14)
- Europe > Spain > Aragón > Zaragoza Province > Zaragoza (0.04)
- Europe > Portugal (0.04)
Sparse Reconstruction of Wavefronts using an Over-Complete Phase Dictionary
Howard, S., Weisse, N., Schroeder, J., Barbero, C., Alonso, B., Sola, I., Norreys, P., Döpp, A.
Wavefront reconstruction is a critical component in various optical systems, including adaptive optics, interferometry, and phase contrast imaging. Traditional reconstruction methods often employ either the Cartesian (pixel) basis or the Zernike polynomial basis. While the Cartesian basis is adept at capturing high-frequency features, it is susceptible to overfitting and inefficiencies due to the high number of degrees of freedom. The Zernike basis efficiently represents common optical aberrations but struggles with complex or non-standard wavefronts such as optical vortices, Bessel beams, or wavefronts with sharp discontinuities. This paper introduces a novel approach to wavefront reconstruction using an over-complete phase dictionary combined with sparse representation techniques. By constructing a dictionary that includes a diverse set of basis functions - ranging from Zernike polynomials to specialized functions representing optical vortices and other complex modes - we enable a more flexible and efficient representation of complex wavefronts. Furthermore, a trainable affine transform is implemented to account for misalignment. Utilizing principles from compressed sensing and sparse coding, we enforce sparsity in the coefficient space to avoid overfitting and enhance robustness to noise.
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- Europe > United Kingdom > England > Oxfordshire > Oxford (0.04)
- Europe > Germany > North Rhine-Westphalia > Upper Bavaria > Munich (0.04)
Exact Wavefront Propagation for Globally Optimal One-to-All Path Planning on 2D Cartesian Grids
Ibrahim, Ibrahim, Gillis, Joris, Decré, Wilm, Swevers, Jan
This paper introduces an efficient $\mathcal{O}(n)$ compute and memory complexity algorithm for globally optimal path planning on 2D Cartesian grids. Unlike existing marching methods that rely on approximate discretized solutions to the Eikonal equation, our approach achieves exact wavefront propagation by pivoting the analytic distance function based on visibility. The algorithm leverages a dynamic-programming subroutine to efficiently evaluate visibility queries. Through benchmarking against state-of-the-art any-angle path planners, we demonstrate that our method outperforms existing approaches in both speed and accuracy, particularly in cluttered environments. Notably, our method inherently provides globally optimal paths to all grid points, eliminating the need for additional gradient descent steps per path query. The same capability extends to multiple starting positions. We also provide a greedy version of our algorithm as well as open-source C++ implementation of our solver.
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- North America > United States > New York > New York County > New York City (0.04)
- Europe > United Kingdom > England > Cambridgeshire > Cambridge (0.04)
- Europe > Netherlands (0.04)
Occupation-aware planning method for robotic monitoring missions in dynamic environments
Marchukov, Yaroslav, Montano, Luis
This paper presents a method for robotic monitoring missions in the presence of moving obstacles. Although the scenario map is known, the robot lacks information about the movement of dynamic obstacles during the monitoring mission. Numerous local planners have been developed in recent years for navigating highly dynamic environments. However, the absence of a global planner for these environments can result in unavoidable collisions or the inability to successfully complete missions in densely populated areas, such as a scenario monitoring in our case. This work addresses the development and evaluation of a global planner, $MADA$ (Monitoring Avoiding Dynamic Areas), aimed at enhancing the deployment of robots in such challenging conditions. The robot plans and executes the mission using the proposed two-step approach. The first step involves selecting the observation goal based on the environment's distribution and estimated monitoring costs. In the second step, the robot identifies areas with moving obstacles and obtains paths avoiding densely occupied dynamic regions based on their occupation. Quantitative and qualitative results based on simulations and on real-world experimentation, confirm that the proposed method allows the robot to effectively monitor most of the environment while avoiding densely occupied dynamic areas.
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- Europe > Spain > Aragón > Zaragoza Province > Zaragoza (0.04)
- Europe > Germany > Bavaria > Upper Bavaria > Munich (0.04)
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Prediction-for-CompAction: navigation in social environments using generalized cognitive maps
Atienza, José Antonio Villacorta, Tapia, Carlos Calvo, Slizneva, Valeriy A. Makarov
The ultimate navigation efficiency of mobile robots in human environments will depend on how we will appraise them: merely as impersonal machines or as human-like agents. In the latter case, an agent may take advantage of the cooperative collision avoidance, given that it possesses recursive cognition, i.e.,the agent's decisions depend on the decisions made by humans that in turn depend on the agent's decisions. To deal with this high-level cognitive skill, we propose a neural network architecture implementing Prediction-for-CompAction paradigm. The network predicts possible human-agent collisions and compacts the time dimension by projecting a given dynamic situation into a static map. Thereby emerging compact cognitive map can be readily used as a "dynamic GPS" for planning actions or mental evaluation of the convenience of cooperation in a given context. We provide numerical evidence that cooperation yields additional room for more efficient navigation in cluttered pedestrian flows, and the agent can choose path to the target significantly shorter than a robot treated by humans as a functional machine. Moreover, the navigation safety, i.e., the chances to avoid accidental collisions, increases under cooperation. Remarkably, these benefits yield no additional load to the mean society effort. Thus, the proposed strategy is socially compliant, and the humanoid agent can behave as "one of us".
- Europe > Spain > Galicia > Madrid (0.04)
- North America > United States > New York > New York County > New York City (0.04)
- Information Technology > Artificial Intelligence > Robots (1.00)
- Information Technology > Artificial Intelligence > Machine Learning > Neural Networks (1.00)
- Information Technology > Artificial Intelligence > Cognitive Science (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Agents (0.68)
Adversarial Path Planning for Optimal Camera Positioning
Carenini, Gaia, Duplessis, Alexandre
The use of visual sensors is flourishing, driven among others by the several applications in detection and prevention of crimes or dangerous events. While the problem of optimal camera placement for total coverage has been solved for a decade or so, that of the arrangement of cameras maximizing the recognition of objects "in-transit" is still open. The objective of this paper is to attack this problem by providing an adversarial method of proven optimality based on the resolution of Hamilton-Jacobi equations. The problem is attacked by first assuming the perspective of an adversary, i.e. computing explicitly the path minimizing the probability of detection and the quality of reconstruction. Building on this result, we introduce an optimality measure for camera configurations and perform a simulated annealing algorithm to find the optimal camera placement.
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- Europe > United Kingdom > England > Oxfordshire > Oxford (0.04)
- Europe > Sweden > Stockholm > Stockholm (0.04)
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- Information Technology > Artificial Intelligence > Vision (1.00)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Planning & Scheduling (0.65)
- Information Technology > Artificial Intelligence > Representation & Reasoning > Optimization (0.46)
- Information Technology > Artificial Intelligence > Machine Learning > Statistical Learning > Gradient Descent (0.35)
Towards on-sky adaptive optics control using reinforcement learning
Nousiainen, J., Rajani, C., Kasper, M., Helin, T., Haffert, S. Y., Vérinaud, C., Males, J. R., Van Gorkom, K., Close, L. M., Long, J. D., Hedglen, A. D., Guyon, O., Schatz, L., Kautz, M., Lumbres, J., Rodack, A., Knight, J. M., Miller, K.
The direct imaging of potentially habitable Exoplanets is one prime science case for the next generation of high contrast imaging instruments on ground-based extremely large telescopes. To reach this demanding science goal, the instruments are equipped with eXtreme Adaptive Optics (XAO) systems which will control thousands of actuators at a framerate of kilohertz to several kilohertz. Most of the habitable exoplanets are located at small angular separations from their host stars, where the current XAO systems' control laws leave strong residuals.Current AO control strategies like static matrix-based wavefront reconstruction and integrator control suffer from temporal delay error and are sensitive to mis-registration, i.e., to dynamic variations of the control system geometry. We aim to produce control methods that cope with these limitations, provide a significantly improved AO correction and, therefore, reduce the residual flux in the coronagraphic point spread function. We extend previous work in Reinforcement Learning for AO. The improved method, called PO4AO, learns a dynamics model and optimizes a control neural network, called a policy. We introduce the method and study it through numerical simulations of XAO with Pyramid wavefront sensing for the 8-m and 40-m telescope aperture cases. We further implemented PO4AO and carried out experiments in a laboratory environment using MagAO-X at the Steward laboratory. PO4AO provides the desired performance by improving the coronagraphic contrast in numerical simulations by factors 3-5 within the control region of DM and Pyramid WFS, in simulation and in the laboratory. The presented method is also quick to train, i.e., on timescales of typically 5-10 seconds, and the inference time is sufficiently small (< ms) to be used in real-time control for XAO with currently available hardware even for extremely large telescopes.
- North America > United States > Arizona > Pima County > Tucson (0.14)
- Asia > Japan > Honshū > Kantō > Tokyo Metropolis Prefecture > Tokyo (0.14)
- North America > United States > New Mexico > Bernalillo County > Albuquerque (0.04)
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