Quinn Smithwick

Rapid hologram generation utilizing layer-based approach and graphic rendering for realistic three-dimensional image reconstruction by angular tiling

Abstract. An approach of rapid hologram generation for the realistic three-dimensional (3-D) image reconstruction based on the angular tiling concept is proposed, using a new graphic rendering approach integrated with a previously developed layer-based method for hologram calculation. A 3-D object is simplified as layered cross-sectional images perpendicular to a chosen viewing direction, and our graphics rendering approach allows the incorporation of clear depth cues, occlusion, and shading in the generated holograms for angular tiling. The combination of these techniques together with parallel computing reduces the computation time of a single-view hologram for a 3-D image of extended graphics array resolution to 176 ms using a single consumer graphics processing unit card.

High optical and switching performance electrochromic devices based on a zinc oxide nanowire with poly(methyl methacrylate) gel electrolytes

High performance electrochromic devices have been fabricated and demonstrated utilizing a solid polymer electrolyte and zinc oxide (ZnO) nanowire (NW) array counter electrode. The poly(methyl methacrylate) based polymer electrolyte was spin coated upon hydrothermally grown ZnO NW array counter electrodes, while electron beam evaporated NiOx thin films formed the working electrodes. Excellent optical contrast and switching speeds were observed in the fabricated devices with active areas of 2 cm2, exhibiting an optical contrast of 73.11% at the wavelength of 470 nm, combined with a fast switching time of 0.2 s and 0.4 s for bleaching and coloration, respectively.

Multi-Layered Automultiscopic Displays

Our hybrid display model combines multiple automultiscopic elements volumetrically to support horizontal and vertical parallax at a larger depth of field and better accommodation cues compared to single layer elements. In this paper, we introduce a framework to analyze the bandwidth of such display devices. Based on this analysis, we show that multiple layers can achieve a wider depth of field using less bandwidth compared to single layer displays. We present a simple algorithm to distribute an input light field to multiple layers, and devise an efficient ray tracing algorithm for synthetic scenes. We demonstrate the effectiveness of our approach by both software simulation and two corresponding hardware prototypes.

A volumetric display based on a rim-driven varifocal beamsplitter and LED backlit LCD

We demonstrate a volumetric display providing high resolution, full color, real images with 10 addressable depth planes and correct focus and vergence cues for the viewer. The display is centered around a novel optical element; a large-aperture, rim-driven, adjustable-resonance, varifocal beamsplitter.

Implementation of shading effect for reconstruction of smooth layer-based 3D holographic images

A holographic rendering algorithm using a layer-based structure with angular tiling supports view-dependent shading and accommodation cues. This approach also has the advantages of rapid computation speed and visual reduction of layer gap artefacts compared to other approaches. Holograms rendered with this algorithm are displayed using an SLM to demonstrate view-dependent shading and occlusion.

Coding/decoding two-dimensional images with orbital angular momentum of light

We investigate encoding and decoding of two-dimensional information using the orbital angular momentum (OAM) of light. Spiral phase plates and phase-only spatial light modulators are used in encoding and decoding of OAM states, respectively. We show that off-axis points and spatial variables encoded with a given OAM state can be recovered through decoding with the corresponding complimentary OAM state.

Automultiscopic displays based on orbital angular momentum of light

Orbital angular momentum (OAM) of light has drawn increasing attention due to its intriguingly rich physics and potential for a variety of applications. Having an unbounded set of orthogonal states, OAM has been used to enhance the channel capacity of data transmission. We propose and demonstrate the viability of using OAM to create an automultiscopic 3D display. Multi-view image information is encoded using an OAM beam array, then sorted into different view directions using coordinate transformation elements. A three-view demonstration was achieved to encode and decode 9 × 9 pixel images. These demonstrations suggest that OAM could potentially serve as an additional platform for future 3D display systems.

LCD masks for spatial augmented reality

One aim of Spatial Augmented Reality is to visually integrate synthetic objects into real-world spaces amongst physical objects, viewable by many observers without 3D glasses, head-mounted displays or mobile screens. In common implementations, using beam-combiners, scrim projection, or transparent self-emissive displays, the synthetic object’s and real-world scene’s light combine additively. As a result, synthetic objects appear low-contrast and semitransparent against well-lit backgrounds, and do not cast shadows. These limitations prevent synthetic objects from appearing solid and visually integrated into the real-world space. We use a transparent LCD panel as a programmable dynamic mask. The LCD panel displaying the synthetic object’s silhouette mask is colocated with the object’s color image, both staying aligned for all points-of-view. The mask blocks the background providing occlusion, presents a black level for high-contrast images, blocks scene illumination thus casting true shadows, and prevents blow-by in projection scrim arrangements. We have several implementations of SAR with LCD masks: 1) beam-combiner with an LCD mask, 2) scrim projection with an LCD mask, and 3) transparent OLED display with an LCD mask. Large format (80” diagonal) and dual layer volumetric variations are also implemented.

Switching dual layer display with dynamic LCD mask

The Switching Dual Layer Display with a Dynamic LCD Mask is a multi-layer three-dimensional display capable of independent layer content and occlusion between layers. The display consists of a spaced stack of transparent LCD panel and LCD monitor synchronously switching between content, mask, and backlight states. In the first state, the back layer displays white and the front layer displays its content. The back layer acts as a backlight for the front layer, making the front layer content visible. In the second state, the back layer displays content and the front layer displays a mask. The back layer content is occluded by the front layer mask. Rapidly alternating between states, the viewer perceives opaque high-contrast foreground content occluding the background. Besides multi-plane imagery, depth-blending using opacity allows for smooth 3D volumetric imagery at the cost of reduced field of view. The addition of a relay mirror and a phantom mask allows solid appearing front layer content to optically float above and occlude the back layer. The floating front layer is non-physical, so both display layers are accessible for interactive applications.

SWITCHED EMISSIVE TRANSPARENT DISPLAY WITH CONTROLLABLE PER-PIXEL OPACITY

An emissive transparent display with per-pixel opacity employs rapid synchronized switching of a transparent display and transparent backlight between content with a scattering luminous backlight, and masks with a clear unlit backlight. A 144 fps transparent LCD panel is used in conjunction with a transparent backlight, controllably diffusive smartglass screen, and optional switching background lighting. The display is capable of producing opaque emissive content on a transparent field for novel transparent display and compact spatial augmented reality applications.