Content-adaptive lenticular prints

Lenticular prints are a popular medium for producing automultiscopic glasses-free 3D images. The light field emitted by such prints has a fixed spatial and angular resolution. We increase both perceived angular and spatial resolution by modifying the lenslet array to better match the content of a given light field. Our optimization algorithm analyzes the input light field and computes an optimal lenslet size, shape, and arrangement that best matches the input light field given a set of output parameters. The resulting emitted light field shows higher detail and smoother motion parallax compared to fixed-size lens arrays. We demonstrate our technique using rendered simulations and by 3D printing lens arrays, and we validate our approach in simulation with a user study

Improving visual quality of view transitions in automultiscopic displays

Automultiscopic screens present different images depending on the viewing direction. This enables glasses-free 3D and provides motion parallax effect. However, due to the limited angular resolution of such displays, they suffer from hot-spotting, i. e., image quality is highly affected by the viewing position. In this paper, we analyze light fields produced by lenticular and parallax-barrier displays, and show that, unlike in real world, the light fields produced by such screens have a repetitive structure. This induces visual artifacts in the form of view discontinuities, depth reversals, and excessive disparities when viewing position is not optimal. Although the problem has been always considered as inherent to the technology, we demonstrate that light fields reproduced on automultiscopic displays have enough degrees of freedom to improve the visual quality. We propose a new technique that modifies light fields using global and local shears followed by stitching to improve their continuity when displayed on a screen. We show that this enhances visual quality significantly, which is demonstrated in a series of user experiments with an automultiscopic display as well as lenticular prints.National Science Foundation (U.S.) (IIS-1111415)National Science Foundation (U.S.) (IIS-1116296)Quanta Computer (Firm)National Basic Research Program of China (973 Program) (Project 2011CB302205)National Natural Science Foundation (China) (Project 61272226/61120106007)National High-Tech R&D (863) Plan of China (Project 2013AA013903)Beijing Higher Institution Engineering Research Center (Research Grant

A compressive light field projection system

For about a century, researchers and experimentalists have strived to bring glasses-free 3D experiences to the big screen. Much progress has been made and light field projection systems are now commercially available. Unfortunately, available display systems usually employ dozens of devices making such setups costly, energy inefficient, and bulky. We present a compressive approach to light field synthesis with projection devices. For this purpose, we propose a novel, passive screen design that is inspired by angle-expanding Keplerian telescopes. Combined with high-speed light field projection and nonnegative light field factorization, we demonstrate that compressive light field projection is possible with a single device. We build a prototype light field projector and angle-expanding screen from scratch, evaluate the system in simulation, present a variety of results, and demonstrate that the projector can alternatively achieve super-resolved and high dynamic range 2D image display when used with a conventional screen.MIT Media Lab ConsortiumNatural Sciences and Engineering Research Council of Canada (NSERC Postdoctoral Fellowship)National Science Foundation (U.S.) (Grant NSF grant 0831281

The creation and persistence of a misaligned gas disc in a simulated early-type galaxy

Massive early-type galaxies commonly have gas discs which are kinematically misaligned with the stellar component. These discs feel a torque from the stars and the angular momentum vectors are expected to align quickly. We present results on the evolution of a misaligned gas disc in a cosmological simulation of a massive early-type galaxy from the Feedback In Realistic Environments project. This galaxy experiences a merger which, together with a strong galactic wind, removes most of the original gas disc. The galaxy subsequently reforms a gas disc through accretion of cold gas, but it is initially 120 degrees misaligned with the stellar rotation axis. This misalignment persists for about 2 Gyr before the gas-star misalignment angle drops below 20 degrees. The time it takes for the gaseous and stellar components to align is much longer than previously thought, because the gas disc is accreting a significant amount of mass for about 1.5 Gyr after the merger, during which the angular momentum change induced by accreted gas dominates over that induced by stellar torques. Once the gas accretion rate has decreased sufficiently, the gas disc decouples from the surrounding halo gas and realigns with the stellar component in about 6 dynamical times. During the late evolution of the misaligned gas disc, the centre aligns faster than the outskirts, resulting in a warped disc. We discuss the observational consequences of the long survival of our misaligned gas disc and how our results can be used to calibrate merger rate estimates from observed gas misalignments.Comment: 10 pages, 7 figures. Accepted for publication in MNRAS. Revised version: minor changes. A movie of the evolution of the gas disc can be viewed at http://astro.berkeley.edu/~freeke/misalign.htm