KEYWORDS: Digital micromirror devices, 3D displays, Super resolution, Cameras, Calibration, Image resolution, 3D image processing, Projection systems, Image processing, Relays
We describe a projection system that presents a 20 megapixel image using a single XGA SLM and time-division
multiplexing. The system can be configured as a high-resolution 2-D display or a highly multi-view horizontal parallax
display. In this paper, we present a technique for characterizing the light transport function of the display and for
precompensating the image for the measured transport function. The techniques can improve the effective quality of the
display without modifying its optics. Precompensation is achieved by approximately solving a quadratic optimization
problem. Compared to a linear filter, this technique is not limited by a fixed kernel size and can propagate image detail
to all related pixels. Large pixel-count images are supported through dividing the problem into blocks. A remedy for
blocking artifacts is given. Results of the algorithm are presented based on simulations of a display design. The display
characterization method is suitable for experimental designs that may be dim and imperfectly aligned. Simulated results
of the characterization and precompensation process are presented. RMS and qualitative improvement of display image
quality are demonstrated.
KEYWORDS: 3D displays, Radiotherapy, 3D volumetric displays, Visualization, Tumors, 3D image processing, Human-machine interfaces, Computed tomography, Cancer
We describe PerspectaRAD, the first tool for the review and modification of external-beam radiation therapy treatment
plans with a volumetric three-dimensional display (Perspecta 1.9, Actuality Medical, Bedford, MA, USA) and a dedicated software application (PerspectaRAD, Actuality Medical). We summarize
multi-institution retrospective studies that compare the system's efficacy to the incumbent 2-D display-based workflow. Contributions include: visualizing the treatment plan in a volumetric 3-D display, modifying the beam locations and performing point-and-click measurement in 3-D with a 3-D physical interface, and simultaneously viewing volumetric projections of the native CT data and isodose contours. The plans are synchronized with the hospital treatment planning system, Pinnacle3 (Philips Medical, WI, USA). In the largest of five studies, 33 plans were retrospectively randomized and replanned at three institutions, including 12 brain, 10 lung, and 11 abdomen / pelvis. The PerspectaRAD plan was as good as or better than plans created without PerspectaRAD 70% of the time. Radiation overdose regions were more likely to be obvious inside the target volume than when reviewed in the 2-D display alone. However, the planning time was longer with PerspectaRAD. The data demonstrate that PerspectaRAD facilitates the use of non-coplanar beams and has significant potential to achieve better plan quality in radiation therapy.
KEYWORDS: 3D displays, Visualization, 3D image processing, Electronics, 3D volumetric displays, Projection systems, Digital micromirror devices, OpenGL, 3D applications, Software frameworks
We present a software and hardware foundation to enable the rapid adoption of 3-D displays. Different 3-D displays - such as multiplanar, multiview, and electroholographic displays - naturally require different rendering methods. The adoption of these displays in the marketplace will be accelerated by a common software framework. The authors designed the SpatialGL API, a new rendering framework that unifies these display methods under one interface. SpatialGL enables complementary visualization assets to coexist through a uniform infrastructure. Also, SpatialGL supports legacy interfaces such as the OpenGL API. The authors’ first implementation of SpatialGL uses multiview and multislice rendering algorithms to exploit the performance of modern graphics processing units (GPUs) to enable real-time visualization of 3-D graphics from medical imaging, oil & gas exploration, and homeland security. At the time of writing, SpatialGL runs on COTS workstations (both Windows and Linux) and on Actuality’s high-performance embedded computational engine that couples an NVIDIA GeForce 6800 Ultra GPU, an AMD Athlon 64 processor, and a proprietary, high-speed, programmable volumetric frame buffer that interfaces to a 1024 x 768 x 3 digital projector. Progress is illustrated using an off-the-shelf multiview display, Actuality’s multiplanar Perspecta Spatial 3D System, and an experimental multiview display. The experimental display is a quasi-holographic view-sequential system that generates aerial imagery measuring 30 mm x 25 mm x 25 mm, providing 198 horizontal views.
A 360-degree-viewable volumetric 3-D display has been developed by Actuality Systems, Inc. It has a resolution of 768 x 768 x 198, has a 24 Hz refresh rate, contains an embedded graphics processing system, and uses dithering methods to create images of 3-bit to 21-bit color. The 3-D display system is a visualization platform, comprised of a combination of hardware and software designed for ease-of-integration into existing visualization systems. The system design is briefly recounted. Key enhancements are described, such as the development of a volumetric visualization software platform. Examples are given which guide the system engineer who needs to include a volumetric display into a visualization solution.
KEYWORDS: 3D displays, Visualization, 3D volumetric displays, 3D image processing, Raster graphics, Projection systems, OpenGL, Digital signal processing, Electronics
An 8-color multiplanar volumetric display is being developed by Actuality Systems, Inc. It will be capable of utilizing an image volume greater than 90 million voxels, which we believe is the greatest utilizable voxel set of any volumetric display constructed to date. The display is designed to be used for molecular visualization, mechanical CAD, e-commerce, entertainment, and medical imaging. As such, it contains a new graphics processing architecture, novel high-performance line- drawing algorithms, and an API similar to a current standard. Three-dimensional imagery is created by projecting a series of 2-D bitmaps ('image slices') onto a diffuse screen that rotates at 600 rpm. Persistence of vision fuses the slices into a volume-filling 3-D image. A modified three-panel Texas Instruments projector provides slices at approximately 4 kHz, resulting in 8-color 3-D imagery comprised of roughly 200 radially-disposed slices which are updated at 20 Hz. Each slice has a resolution of 768 by 768 pixels, subtending 10 inches. An unusual off-axis projection scheme incorporating tilted rotating optics is used to maintain good focus across the projection screen. The display electronics includes a custom rasterization architecture which converts the user's 3- D geometry data into image slices, as well as 6 Gbits of DDR SDRAM graphics memory.
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