Advances in display technology and 3D design visualization applications have made real-time stereoscopic visualization of architectural and engineering projects a reality. Parsons Brinkerhoff (PB) is a transportation consulting firm that has used digital visualization tools from their inception and has helped pioneer the application of those tools to large scale infrastructure projects. PB is one of the first Architecture/Engineering/Construction (AEC) firms to implement a CAVE- an immersive presentation environment that includes stereoscopic rear-projection capability. The firm also employs a portable stereoscopic front-projection system, and shutter-glass systems for smaller groups. PB is using commercial real-time 3D applications in combination with traditional 3D modeling programs to visualize and present large AEC projects to planners, clients and decision makers in stereo. These presentations create more immersive and spatially realistic presentations of the proposed designs. This paper will present the basic display tools and applications, and the 3D modeling techniques PB is using to produce interactive stereoscopic content. The paper will discuss several architectural and engineering design visualizations we have produced.

A new technique is presented for visualizing high-resolution terrain elevation data. It produces realistic images at small scales on the order of the data resolution and works particularly well when natural objects are present. Better visualization at small scales opens up new applications, like site surveillance for security and Google Earth-type local search and exploration tasks that are now done with 2-D maps. The large 3-D maps are a natural for high-resolution stereo display. The traditional technique drapes a continuous surface over the regularly spaced elevation values. This technique works well when displaying large areas or in cities with large buildings, but falls apart at small scales or for natural objects like trees. The new technique visualizes the terrain as a set of disjoint square patches. It is combined with an algorithm that identifies smooth areas within the scene. Where the terrain is smooth, such as in grassy areas, roads, parking lots and rooftops, it warps the patches to create a smooth surface. For trees or shrubs or other areas where objects are under-sampled, however, the patches are left disjoint. This has the disadvantage of leaving gaps in the data, but the human mind is very adept at filling in this missing information. It has the strong advantage of making natural terrain look realistic, trees and bushes look stylized but still look natural and are easy to interpret. Also, it does not add artifacts to the map, like filling in blank vertical walls where there are alcoves and other structure and extending bridges and overpasses down to the ground. The new technique is illustrated using very large 1-m resolution 3-D maps from the Rapid Terrain Visualization (RTV) program, and comparisons are made with traditional visualizations using these maps.

Autostereoscopy (AS) is an increasingly valuable virtual reality (VR) display technology; indeed, the IS&T / SPIE Electronic Imaging Conference has seen rapid growth in the number and scope of AS papers in recent years. The first Varrier paper appeared at SPIE in 2001, and much has changed since then. What began as a single-panel prototype has grown to a full scale VR autostereo display system, with a variety of form factors, features, and options. Varrier is a barrier strip AS display system that qualifies as a true VR display, offering a head-tracked ortho-stereo first person interactive VR experience without the need for glasses or other gear to be worn by the user. Since Varrier's inception, new algorithmic and systemic developments have produced performance and quality improvements. Visual acuity has increased by a factor of 1.4X with new fine-resolution barrier strip linescreens and computational algorithms that support variable sub-pixel resolutions. Performance has improved by a factor of 3X using a new GPU shader-based sub-pixel algorithm that accomplishes in one pass what previously required three passes. The Varrier modulation algorithm that began as a computationally expensive task is now no more costly than conventional stereoscopic rendering. Interactive rendering rates of 60 Hz are now possible in Varrier for complex scene geometry on the order of 100K vertices, and performance is GPU bound, hence it is expected to continue improving with graphics card enhancements. Head tracking is accomplished with a neural network camera-based tracking system developed at EVL for Varrier. Multiple cameras capture subjects at 120 Hz and the neural network recognizes known faces from a database and tracks them in 3D space. New faces are trained and added to the database in a matter of minutes, and accuracy is comparable to commercially available tracking systems. Varrier supports a variety of VR applications, including visualization of polygonal, ray traced, and volume rendered data. Both AS movie playback of pre-rendered stereo frames and interactive manipulation of 3D models are supported. Local as well as distributed computation is employed in various applications. Long-distance collaboration has been demonstrated with AS teleconferencing in Varrier. A variety of application domains such as art, medicine, and science have been exhibited, and Varrier exists in a variety of form factors from large tiled installations to smaller desktop forms to fit a variety of space and budget constraints. Newest developments include the use of a dynamic parallax barrier that affords features that were inconceivable with a static barrier.

While discussing the current state of stereo head-mounted and 3D projection displays, the authors came to the realization that flat-panel LCD displays offer higher resolution than projection for stereo display at a low (and continually dropping) cost. More specifically, where head-mounted displays of moderate resolution and field-of-view cost tens of thousands of dollars, we can achieve an angular resolution approaching that of the human eye with a field-of-view (FOV) greater than 90° for less than $1500. For many immersive applications head tracking is unnecessary and sometimes even undesirable, and a low cost/high quality wide FOV display may significantly increase the application space for 3D display. After outlining the problem and potential of this solution we describe the initial construction of a simple Wheatstone stereoscope using 24" LCD displays and then show engineering improvements that increase the FOV and usability of the system. The applicability of a high-immersion, high-resolution display for art, entertainment, and simulation is presented along with a content production system that utilizes the capabilities of the system. We then discuss the potential use of the system for VR pain control therapy, treatment of post-traumatic stress disorders and other serious games applications.

In this paper we define an innovative modular real-time system to visualize, capture, manage, securely preserve, store and playback stereoscopic images. The system, called "Solid-Look" together with the cameras "StereOpsis" will allow military, EOD specialists, and private industry operators to literally "see through the robot's eyes". The system enables the operator to control the robot as if his/her head were located on the robot itself, positioning and zooming the camera to the visual target object using the operator's eye and head movement, without any wearable devices and allowing the operator's hands to perform other tasks. The stereo cameras perform zooming and image stabilization for a controlled and smooth vision. The display enables stereoscopic vision without the need of glasses. Every image frame is authenticated, encrypted and timestamped to allow certainty and confidentiality during post-capture playback or to show evidence in court. The system secures the ability to operate it, requiring administrator's biometrical authentication. Solid-Look modular design can be used in multiple industries from Homeland Security to Pharmaceutical including research, forensic and underwater inspections and will certainly provide great benefit to the performance, speed and accuracy of the operations.

The computerization of the clinical record and the realization of the multimedia have brought improvement of the medical service in medical facilities. It is very important for the patients to obtain comprehensible informed consent. Therefore, the doctor should plainly explain the purpose and the content of the diagnoses and treatments for the patient. We propose and design a Telemedicine Imaging Collaboration System which presents a three dimensional medical image as X-ray CT, MRI with stereoscopic image by using virtual common information space and operating the image from a remote location. This system is composed of two personal computers, two 15 inches stereoscopic parallax barrier type LCD display (LL-151D, Sharp), one 1Gbps router and 1000base LAN cables. The software is composed of a DICOM format data transfer program, an operation program of the images, the communication program between two personal computers and a real time rendering program. Two identical images of 512×768 pixcels are displayed on two stereoscopic LCD display, and both images show an expansion, reduction by mouse operation. This system can offer a comprehensible three-dimensional image of the diseased part. Therefore, the doctor and the patient can easily understand it, depending on their needs.

Introduction: While there is an increasing demand for minimally invasive operative techniques in Ear, Nose and Throat surgery, these operations are difficult to learn for junior doctors and demanding to supervise for experienced surgeons. The motivation for this study was to integrate high-definition (HD) stereoscopic video monitoring in microscopic surgery in order to facilitate teaching interaction between senior and junior surgeon. Material and methods: We attached a 1280x1024 HD stereo camera (TrueVisionSystems^TM Inc., Santa Barbara, CA, USA) to an operating microscope (Zeiss ProMagis, Zeiss Co., Oberkochen, Germany), whose images were processed online by a PC workstation consisting of a dual Intel® Xeon® CPU (Intel Co., Santa Clara, CA). The live image was displayed by two LCD projectors @ 1280x768 pixels on a 1,25m rear-projection screen by polarized filters. While the junior surgeon performed the surgical procedure based on the displayed stereoscopic image, all other participants (senior surgeon, nurse and medical students) shared the same stereoscopic image from the screen. Results: With the basic setup being performed only once on the day before surgery, fine adjustments required about 10 minutes extra during the operation schedule, which fitted into the time interval between patients and thus did not prolong operation times. As all relevant features of the operative field were demonstrated on one large screen, four major effects were obtained: A) Stereoscopy facilitated orientation for the junior surgeon as well as for medical students. B) The stereoscopic image served as an unequivocal guide for the senior surgeon to demonstrate the next surgical steps to the junior colleague. C) The theatre nurse shared the same image, anticipating the next instruments which were needed. D) Medical students instantly share the information given by all staff and the image, thus avoiding the need for an extra teaching session. Conclusion: High definition stereoscopy bears the potential to compress the learning curve for undergraduate as well as postgraduate medical professionals in minimally invasive surgery. Further studies will focus on the long term effect for operative training as well as on post-processing of HD stereoscopy video content for off-line interactive medical education.

Sophisticated surgeries require the integration of several medical imaging modalities, like MRI and CT, which are three-dimensional. Many efforts are invested in providing the surgeon with this information in an intuitive & easy to use manner. A notable development, made by Visionsense, enables the surgeon to visualize the scene in 3D using a miniature stereoscopic camera. It also provides real-time 3D measurements that allow registration of navigation systems as well as 3D imaging modalities, overlaying these images on the stereoscopic video image in real-time. The real-time MIS 'see through tissue' fusion solutions enable the development of new MIS procedures in various surgical segments, such as spine, abdomen, cardio-thoracic and brain. This paper describes 3D surface reconstruction and registration methods using Visionsense camera, as a step toward fully automated multi-modality 3D registration.

We have developed a novel VR task: the Dynamic Reaching Test, that measures human forearm movement in 3D space. In this task, three different stereoscopic displays: autostereoscopic (AS), shutter glasses (SG) and head mounted display (HMD), are used in tests in which subjects must catch a virtual ball thrown at them. Parameters such as percentage of successful catches, movement efficiency (subject path length compared to minimal path length), and reaction time are measured to evaluate differences in 3D perception among the three stereoscopic displays. The SG produces the highest percentage of successful catches, though the difference between the three displays is small, implying that users can perform the VR task with any of the displays. The SG and HMD produced the best movement efficiency, while the AS was slightly less efficient. Finally, the AS and HMD produced similar reaction times that were slightly higher (by 0.1 s) than the SG. We conclude that SG and HMD displays were the most effective, but only slightly better than the AS display.

In this paper, we propose an improved triangulation method for building parallel-perspective stereo mosaics using ray interpolation. The currently available fast PRISM (Parallel Ray Interpolation for Stereo Mosaicing) uses a constant triangulation technique that does not take advantage of the spatial information. This works well when the inter-frame displacement in the video is small. However, for large inter-frame displacements, hence large motion parallax, we observe visual artifacts in the mosaics when the source triangles in the video frames are warped into destination triangles in the mosaics using affine transformations. Our method uses the edge information present in the scene to ensure that triangles do not cross over from one planar facet to the other. The video frames are segmented and the edges are obtained from the boundaries of different segments. The motion over the entire region in each triangle is constant. Hence, this method avoids unwanted warping of objects with large motion parallax in the scene and reduces the visual artifacts. The performance of our proposed technique is demonstrated on a series of simple to complex video imagery collected by utilizing cameras and airborne sensors.

Previously we demonstrated that surrogate depth maps, consisting of "depth" values mainly at object boundaries in the image of a scene, are effective for converting 2D images to stereoscopic 3D images using depth image based rendering. In this study we examined the use of surrogate depth maps whose depth edges were derived from cast shadows located in multiple images (Multiflash method). This method has the capability to delineate actual depth edges, in contrast to methods based on (Sobel) edge identification and (Standard Deviation) local luminance distribution. A group of 21 nonexpert viewers assessed the depth quality and visual comfort of stereoscopic images generated using these three methods on two sets of source images. Stereoscopic images based on the Multiflash method provided an enhanced depth quality that is better than the depth provided by a reference monoscopic image. Furthermore, the enhanced depth was comparable to that observed with the other two methods. However, all three methods generated images that were rated "mildly uncomfortable" or "uncomfortable" to view. It is concluded that there is no advantage in the use of the Multiflash method for creating surrogate depth maps. As well, even though the depth quality produced with surrogate depth maps is sufficiently good, the visual comfort of the stereoscopic images need to be improved before this approach of using surrogate depth maps can be deemed suitable for general use.

We want to create realistic immersive personal virtual environments using stereo panoramas. We explore methods to adjust the disparity of stereoscopic images to lie within an acceptable range for human viewers and provide a comfortable stereo viewing experience. Peleg et al described a disparity adjusting method which modifies the disparity of selected objects but also the columns including the object. In this paper, we develop a human interactive object-based tool to adjust selectively the horizontal disparity in stereo panoramas. It enhances or reduces the stereo visual effect for selected 2D object regions without changing the disparities of other regions in the image. Our interactive object-selecting tool is based on the mean-shift segmentation method. The object presented in either a left or right image is selected by user's inputting seed points near the desired object boundary, and object contours both in left and right image are automatically found by our object-selecting algorithm. The complete interactive disparity-adjusting tool allows the user to select the object either from manual input using a cursor, or by defining an area with a certain distance range, with the ability to observe the results immediately on an autostereoscopic display or other stereo display.

Three-dimensional television (3D-TV) will become the next big step in the development of advanced TV systems. One of the major challenges for the deployment of 3D-TV systems is the diversity of display technologies and the high cost of capturing multi-view content. Depth image-based rendering (DIBR) has been identified as a key technology for the generation of new views for stereoscopic and multi-view displays from a small number of views captured and transmitted. We propose a disparity compensation method for DIBR that does not require spatial interpolation of the disparity map. We use a forward-mapping disparity compensation with real precision. The proposed method deals with the irregularly sampled image resulting from this disparity compensation process by applying a re-sampling algorithm based on a bi-cubic spline function space that produces smooth images. The fact that no approximation is made on the position of the samples implies that geometrical distortions in the final images due to approximations in sample positions are minimized. We also paid attention to the occlusion problem. Our algorithm detects the occluded regions in the newly generated images and uses simple depth-aware inpainting techniques to fill the gaps created by newly exposed areas. We tested the proposed method in the context of generation of views needed for viewing on SynthaGram^TM auto-stereoscopic displays. We used as input either a 2D image plus a depth map or a stereoscopic pair with the associated disparity map. Our results show that this technique provides high quality images to be viewed on different display technologies such as stereoscopic viewing with shutter glasses (two views) and lenticular auto-stereoscopic displays (nine views).

Intermediate view reconstruction is an essential step in content preparation for multiview 3D displays and freeviewpoint video. Although many approaches to view reconstruction have been proposed to date, most of them share the need to model and estimate scene depth first, and follow with the estimation of unknown-view texture using this depth and other views. The approach we present in this paper follows this path as well. First, assuming a reliable disparity (depth) map is known between two views, we present a spline-based approach to unknownview texture estimation, and compare its performance with standard disparity-compensated interpolation. A distinguishing feature of the spline-based reconstruction is that all virtual views between the two known views can be reconstructed from a single disparity field, unlike in disparity-compensated interpolation. In the second part of the paper, we concentrate on the recovery of reliable disparities especially at object boundaries. We outline an occlusion-aware disparity estimation method that we recently proposed; it jointly computes disparities in visible areas, inpaints disparities in occluded areas and implicitly detects occlusion areas. We then show how to combine occlusion-aware disparity estimation with spline-based view reconstruction presented earlier, and we experimentally demonstrate its benefits compared to occlusion-unaware disparity-compensated interpolation.

An improved technique for displaying stereoscopic moving images is described that makes for a more comfortable and enjoyable viewing experience by reducing the conflict of cues that occurs at the vertical edges of the screen surround when objects with negative parallax values are partially occluded. One such means for mitigating the vertical surround edge conflicts is given, in which the convergence of the camera fields is effectively altered to produce the zero parallax condition in the regions of the image immediately adjacent to the vertical edges of the screen surround. The transition is proportional to the proximity to the vertical edge and controlled proportionately. The net effect of this edge treatment is to allow for an increase in the projected image's parallax budget, thereby heightening the overall depth effect.

Desktop 3D displays vary in their optical design and this results in a significant variation in the way in which stereo images are physically displayed on different 3D displays. When precise depth judgements need to be made these differences may become critical to task performance. Applications where this is a particular issue include medical imaging, geoscience and scientific visualization. We investigate perceived depth thresholds for four classes of desktop 3D display; full resolution, row interleaved, column interleaved and colour-column interleaved. Given the same input image resolution we calculate the physical view resolution for each class of display to geometrically predict its minimum perceived depth threshold. To verify our geometric predictions we present the design of a task where viewers are required to judge which of two neighboring squares lies in front of the other. We report results from a trial using this task where participants are randomly asked to judge whether they can perceive one of four levels of image disparity (0,2,4 and 6 pixels) on seven different desktop 3D displays. The results show a strong effect and the task produces reliable results that are sensitive to display differences. However, we conclude that depth judgement performance cannot always be predicted from display geometry alone. Other system factors, including software drivers, electronic interfaces, and individual participant differences must also be considered when choosing a 3D display to make critical depth judgements.

Visual discomfort has been the subject of considerable research in relation to stereoscopic and autostereoscopic displays, but remains an ambiguous concept used to denote a variety of subjective symptoms potentially related to different underlying processes. In this paper we clarify the importance of various causes and aspects of visual comfort. Classical causative factors such as excessive binocular parallax and accommodation-convergence conflict appear to be of minor importance when disparity values do not surpass one degree limit of visual angle, which still provides sufficient range to allow for satisfactory depth perception in consumer applications, such as stereoscopic television. Visual discomfort, however, may still occur within this limit and we believe the following factors to be the most pertinent in contributing to this: (1) excessive demand of accommodation-convergence linkage, e.g., by fast motion in depth, viewed at short distances, (2) 3D artefacts resulting from insufficient depth information in the incoming data signal yielding spatial and temporal inconsistencies, and (3) unnatural amounts of blur. In order to adequately characterize and understand visual discomfort, multiple types of measurements, both objective and subjective, are needed.

This paper presents a simple and inexpensive multiview 3D display system composed of a LCD panel, a convex lens array, and a Fresnel lens. In the proposed system a pair of the LCD fragment and a convex lens in the array plays the role of a projector. The idea of multiview 3D displays composed of multiple projectors and a large convex lens or a concave mirror is old and famous. The conventional methods, however, require diffusers to show continuous motion parallax, which decays the quality of the image. To solve this problem we use a convex lens array with no gaps between the lenses, which realizes continuous motion parallax without diffusers. The convex lens array, however, has to produce images without aberration to show the viewer stable 3D images. It is hard and expensive to realize such lens arrays without gaps between the component lenses. To produce images with little aberration in a simple format, the author proposes the optical system where each component lens makes the parallel light rays instead of creating an image by keeping the distance between the LCD surface and the lens array the same as the focal distance of the component lenses. To create an image, we use a large convex-type Fresnel lens, which has been used only for the purpose of distributing multiview images to each viewpoint in the conventional multi-projection systems. Fresnel lens, receiving parallel light from the lens array, creates a floating real image at its focal distance and attains distribution of multiview images at the same time. With this configuration we can create images with little aberration even when we use a lens array composed of simple convex-type Fresnel lenses widely available with low prices.

Mobile TV is now a commercial reality, and an opportunity exists for the first mass market 3DTV products based on cell phone platforms with switchable 2D/3D autostereoscopic displays. Compared to conventional cell phones, TV phones need to operate for extended periods of time with the display running at full brightness, so the efficiency of the 3D optical system is key. The desire for increased viewing freedom to provide greater viewing comfort can be met by increasing the number of views presented. A four view lenticular display will have a brightness five times greater than the equivalent parallax barrier display. Therefore, lenticular displays are very strong candidates for cell phone 3DTV. Selection of Polarisation Activated Microlens^TM architectures for LCD, OLED and reflective display applications is described. The technology delivers significant advantages especially for high pixel density panels and optimises device ruggedness while maintaining display brightness. A significant manufacturing breakthrough is described, enabling switchable microlenses to be fabricated using a simple coating process, which is also readily scalable to large TV panels. The 3D image performance of candidate 3DTV panels will also be compared using autostereoscopic display optical output simulations.

Although interest in 3D displays that don't require special glasses is growing, developers of 3D displays still face many challenges, such as resolution loss in 3D and 3D/2D convertibility. We have solved these problems with the development of a novel pixel arrangement, called Horizontally Double-Density Pixels (HDDP). In this structure, two pictures (one for the left and one for the right eye) on two adjacent pixels form one square 3D pixel. This doubles the 3D resolution, making it as high as the 2D display and shows 3D images anywhere in 2D images with the same resolution. The display we have developed is lenticular lens based, is 2.5 diagonal inches in size, and has a 320x2 (RL) x 480x3 (RGB) resolution. As a 3D display, the horizontal and vertical resolutions are equal (235 ppi each). A user aptitude investigation was conducted for mobile phone applications. Several kinds of 3D pictures were presented to 345 participants, whose ages ranged from 16 to 54, and their preferences were surveyed. 3D pictures were categorized into three application areas: communication, entertainment, and useful tools in the mobile environment. Eighteen examples of possible 3D applications were listed and put to the vote. The results showed a high acceptance of and interest in this mobile 3D display.

The mobile phone is quickly evolving from a communications device to an application platform and in the process has become the focus for the development of new technologies. The most challenging technical issues for commercializing a 3D phone are a stereoscopic display technology which is suitable for mobile applications as well as a means for driving the display using the limited capabilities of a mobile handset. In this paper we describe a prototype 3D mobile phone which was developed on a commercially available mobile hardware platform. The demonstration handset was retrofitted with a Polarization Activated Microlens^TM array that is 2D/3D switchable and provides both class-leading low crosstalk levels, and suitable brightness characteristics and viewing zones for operation without compromising battery running time. This next generation autostereoscopic display technology, which combines the advantages in brightness of a lenticular 3D display with the 2D/3D switching capability of parallax barrier, is deployed on a 2.2" landscape QVGA TFT LCD base panel. The stereoscopic content solution is an essential component of a commercially viable 3D handset. We describe how a range of stereoscopic software solutions have been developed on the phone's existing application processor without the need for custom hardware.

This research focuses on the conversion of stereoscopic video material into an image + depth format which is suitable for rendering on the multiview auto-stereoscopic displays of Philips. The recent interest shown in the movie industry for 3D significantly increased the availability of stereo material. In this context the conversion from stereo to the input formats of 3D displays becomes an important task. In this paper we present a stereo algorithm that uses multiple footprints generating several depth candidates for each image pixel. We characterize the various matching windows and we devise a robust strategy for extracting high quality estimates from the resulting depth candidates. The proposed algorithm is based on a surface filtering method that employs simultaneously the available depth estimates in a small local neighborhood while ensuring correct depth discontinuities by the inclusion of image constraints. The resulting highquality image-aligned depth maps proved an excellent match with our 3D displays.

Automultiscopic (no glasses, multiview) displays are becoming a viable alternative to 3-D displays with glasses. However, since these displays require multiple views the needed transmission bit rate as well as storage space are of concern. In this paper, we describe results of our research on the compression of still multiview images for display on lenticular or parallax-barrier screens. In one approach, we examine compression of multiplexed images that, unfortunately, have relatively low spatial correlation and thus are difficult to compress. We also study compression/decompression of individual views followed by multiplexing at the receiver. However, instead of using full-resolution views, we apply compression to band-limited and downsampled views in the so-called "N-tile format". Using lower resolution images is acceptable since multiplexing at the receiver involves downsampling from full view resolution anyway. We use three standard compression techniques: JPEG, JPEG-2000 and H.264. While both JPEG standards work with still images and can be applied directly to an N-tile image, H.264, a video compression standard, requires N images of the N-tile format to be treated as a short video sequence. We present numerous experimental results indicating that the H.264 approach achieves significantly better performance than the other three approaches studied.

A 3D video stream is typically obtained from a set of synchronized cameras, which are simultaneously capturing the same scene (multiview video). This technology enables applications such as free-viewpoint video which allows the viewer to select his preferred viewpoint, or 3D TV where the depth of the scene can be perceived using a special display. Because the user-selected view does not always correspond to a camera position, it may be necessary to synthesize a virtual camera view. To synthesize such a virtual view, we have adopted a depth image-based rendering technique that employs one depth map for each camera. Consequently, a remote rendering of the 3D video requires a compression technique for texture and depth data. This paper presents a predictivecoding algorithm for the compression of depth images across multiple views. The presented algorithm provides (a) an improved coding efficiency for depth images over block-based motion-compensation encoders (H.264), and (b), a random access to different views for fast rendering. The proposed depth-prediction technique works by synthesizing/computing the depth of 3D points based on the reference depth image. The attractiveness of the depth-prediction algorithm is that the prediction of depth data avoids an independent transmission of depth for each view, while simplifying the view interpolation by synthesizing depth images for arbitrary view points. We present experimental results for several multiview depth sequences, that result in a quality improvement of up to 1.8 dB as compared to H.264 compression.

We investigated Pi-cell based polarization switches regarding their applications in both glass type and autostereoscopic 3D displays, which employ LCD as an image panel. It is found that Pi-cell should be divided into the number of individually addressable segments to be capable of switching in synchronism with line-by-line image update in order to reduce time-mismatch crosstalk. We estimated the number of segments, sufficient to reduce local and average crosstalk to acceptable level. It is found experimentally that the displayed stereoscopic image has unequal brightness and crosstalk in the right and left channels. The asymmetry of stereoscopic image parameters is probably caused by the asymmetry of rise/fall time, inherent in Pi-cells. The improved driving method capable of symmetrizing the crosstalk and brightness is proposed. It is also shown that the response time acceleration technique (RTA), developed for the reduction of motion blur, is capable of canceling the dynamic crosstalk caused by slow response of LCD pixels.

The use of an LCD equipped with lenticular lenses is an attractive route to achieve an autostereoscopic multi-view 3D display without losing brightness. However, such a display suffers from a low spatial resolution since the pixels are divided over various views. To overcome this problem we developed switchable displays, using LC-filled switchable lenticulars. In this way it is possible to have a high-brightness 3D display capable to regain the full native 2D resolution of the underlying LCD. We showed the feasibility of LC-filled switchable lenticulars in several applications. For applications in which it is advantageous to be able to display 3D and 2D on the same screen, we made a prototype having a matrix electrode structure. A problem with LC-filled lenses is that in the 2D state there is a residual lens effect at oblique angles. This effect and a possible solution are discussed as well.

We have developed an autostereoscopic multi view display with 36view using 15.1" ultra-high resolution LCD. The resolution of LCD used for experiment is QUXGA of 3200x2400. RGB sub pixels are aligned as vertical lines and size of each sub pixel is 0.032 mm by 0.096mm. Parallax barrier are slanted at the angle of tan^-1(1/6) = 9.46 degree and placed before LCD panel to generate viewing zones. Barrier patterns repeated approximately for every 6 pixels of LCD. So, the numbers of pixels decrease by six along the horizontal direction and the vertical direction. Nominal 3D resolution becomes (3200/6) x (2400/6) = 533 x 400. In slanted barrier configuration, the angular luminance profile for each zone overlaps each other. For the case of 2view 3D system, cross-talk between left eye and right eye zone deteriorates 3D image quality. However for multi view 3D, cross-talk between adjacent zones does not always bring about negative effects as image differences between adjacent zones are rather small. As viewers can see pixels from multiple viewing zones at one place, viewers feel 3D image of higher resolution than nominal 533x400 resolutions. Tested 3D images are made by computer graphics, in which camera position and depth of 3D objects are varied. Smooth motion parallax is observed for the limited depth range of 3D object. As depth of 3D object increases, 3D objects are observed not one image but as overlapped multiple images and image flipping becomes noticeable. We changed the barrier conditions so that horizontal angles between each zone are different and 3D image qualities were compared. For each barrier condition of different horizontal angle between viewing zones, we find an acceptable range of 3D object depth and camera displacement between each zone for computer generated images.

We developed a mobile-size integral videography (IV) display that reproduces 60 ray directions. IV is an autostereoscopic video image technique based on integral photography (IP). The IV display consists of a 2-D display and a microlens array. The maximal spatial frequency (MSF) and the number of rays appear to be the most important factors in producing realistic autostereoscopic images. Lens pitch usually determines the MSF of IV displays. The lens pitch and pixel density of the 2-D display determine the number of rays it reproduces. There is a trade-off between the lens pitch and the pixel density. The shape of an elemental image determines the shape of the area of view. We developed an IV display based on the above correlationship. The IV display consists of a 5-inch 900-dpi liquid crystal display (LCD) and a microlens array. The IV display has 60 ray directions with 4 vertical rays and a maximum of 18 horizontal rays. We optimized the color filter on the LCD to reproduce 60 rays. The resolution of the display is 256x192, and the viewing angle is 30 degrees. These parameters are sufficient for mobile game use. Users can interact with the IV display by using a control pad.

We have developed a 128-directional display having SVGA resolution. We had previously constructed 64-directional, 72-directional, and 128-directional displays in order to explore natural 3D display conditions to solve the visual fatigue problem caused by the accommodation-vergence conflict. We found that these displays enlarge the depth of field of an eye imaging system; however, their resolution was as low as ~QVGA. In the present study, we develop a 128-directional display whose resolution is increased to SVGA, thereby enabling investigation of the influence of 3D resolution on human 3D perception. The newly developed display consists of 128 small projectors having SVGA resolution. Each projector uses one LCOS device, and the field sequential technique is used to display color images. All 128 projectors are aligned in a modified 2D arrangement; i.e., all projectors are aligned two-dimensionally and their horizontal positions are made different from one another. All images are displayed in different horizontal directions with a horizontal angle pitch of 0.28°. The horizontal viewing angle is 35.7°, and screen size is 12.8 inches. The display is controlled by a PC cluster consisting of 16 PCs. In order to correct image distortion caused by the aberration of imaging systems, images displayed on the LCOS devices are pre-distorted by reference to correction tables.

A range of advertised "Stereo-Ready" DLP projectors are now available in the market which allow high-quality flickerfree stereoscopic 3D visualization using the time-sequential stereoscopic display method. The ability to use a single projector for stereoscopic viewing offers a range of advantages, including extremely good stereoscopic alignment, and in some cases, portability. It has also recently become known that some consumer DLP projectors can be used for timesequential stereoscopic visualization, however it was not well understood which projectors are compatible and incompatible, what display modes (frequency and resolution) are compatible, and what stereoscopic display quality attributes are important. We conducted a study to test a wide range of projectors for stereoscopic compatibility. This paper reports on the testing of 45 consumer DLP projectors of widely different specifications (brand, resolution, brightness, etc). The projectors were tested for stereoscopic compatibility with various video formats (PAL, NTSC, 480P, 576P, and various VGA resolutions) and video input connections (composite, SVideo, component, and VGA). Fifteen projectors were found to work well at up to 85Hz stereo in VGA mode. Twenty three projectors would work at 60Hz stereo in VGA mode.

A microretarder for stereoscopic display is a film consisting of horizontal or vertical stripes with alternating null and half-wave phase retardation states. An LCD with a microretarder attached on the front side can display good-quality stereoscopic images when viewed with polarization glasses. It is now the easiest and cheapest way to present stereoscopic images on a flat-panel display. However, the space caused by the glass between the retarder layer and the LC layer of the panel seriously limits the vertical view angle, which, in turn, limits the application of this technology. In this paper, a process for thin-film microretarder is developed using reactive liquid crystal. The material and the process are essentially compatible with current LC panel processes. Since the thin-film microretarder is to be fabricated in the cell of an LC panel, the retarder layer and the LC layer can be fabricated as close to each other as possible. A nearly unlimited 3D view angle can be achieved for the display.

An achromatic linear polarization switch (ALPS^TM)is discussed that enables stereoscopic 3D projection systems using conventional linear polarizing eyewear. The ALPS resides at the output of the projection lens and functions as a switchable polarizer. Features include rapid switching, high contrast, and a color-balanced on-state. The ALPS forms a flexible platform for switching between any set of orthogonal polarizations or filter states.

The authors propose an electronic 3D display combining a multiview display and a volumetric display. Conventional multiview displays often give the viewers severe eyestrains because of the contradiction between binocular convergence and focal accommodation of the eyes. Though volumetric displays are free from the contradiction, they cannot express occlusion or gloss of the objects. The proposed system overcomes these disadvantages at once by displaying colors by the multiview display part and fine contrast of edges by the volumetric display part. As for the multiview display we use conventional multiview technologies. As for the volumetric, we use multilayer monochrome TFT liquid crystal panels. Here we can use monochrome panels because the volumetric part is just in charge of expressing edge contrast. This can sufficiently lead proper accommodation since focal accommodation of our eyes is dependent only on the edge of the image. To connect the edges of adjacent panels smoothly, we apply DFD approach, where the point in the middle of two panels is expressed by depiction on both panels.

Recent advances in the framerate of deformable mirror devices (DMDs) coupled with a corresponding increase in the rendering and data transfer capabilities of graphical processing units (GPUs) has lead to the greatly increased viability of temporal multiplexing approaches for 3d display technology. Employing these advances an initial proof of concept four-zone multiscopic display has been demonstrated, with a 8-16 zone large format display in development. Both designs employ a high-speed LCD shutter located at the pupil of the optical train synchronized with a high framerate DMD projector allowing for the formation of multiple viewing zones via persistence of vision. Present results and ongoing progress in the design of the optical train, high speed projector and the associated rendering system.

Many 3D systems work by presenting to the observer stereoscopic pairs of images that are combined to give the impression of a 3D image. Discomfort experienced when viewing for extended periods may be due to several factors, including the presence of optical crosstalk between the stereo image channels. In this paper we use two video cameras and two LCD panels viewed via a Helmholtz arrangement of mirrors, to display a stereoscopic image inherently free of crosstalk. Simple depth discrimination tasks are performed whilst viewing the 3D image and controlled amounts of image crosstalk are introduced by electronically mixing the video signals. Error monitoring and skin conductance are used as measures of workload as well as traditional subjective questionnaires. We report qualitative measurements of user workload under a variety of viewing conditions. This pilot study revealed a decrease in task performance and increased workload as crosstalk was increased. The observations will assist in the design of further trials planned to be conducted in a medical environment.

Most of 3-D displays suffer from interocular crosstalk, i.e., the perception of an unintended view in addition to intended one. The resulting "ghosting" at high-contrast object boundaries is objectionable and interferes with depth perception. In automultiscopic (no glasses, multiview) displays using microlenses or parallax barrier, the effect is compounded since several unintended views may be perceived at once. However, we recently discovered that crosstalk in automultiscopic displays can be also beneficial. Since spatial multiplexing of views in order to prepare a composite image for automultiscopic viewing involves sub-sampling, prior anti-alias filtering is required. To date, anti-alias filter design has ignored the presence of crosstalk in automultiscopic displays. In this paper, we propose a simple multiplexing model that takes crosstalk into account. Using this model we derive a mathematical expression for the spectrum of single view with crosstalk, and we show that it leads to reduced spectral aliasing compared to crosstalk-free case. We then propose a new criterion for the characterization of ideal anti-alias pre-filter. In the experimental part, we describe a simple method to measure optical crosstalk between views using digital camera. We use the measured crosstalk parameters to find the ideal frequency response of anti-alias filter and we design practical digital filters approximating this response. Having applied the designed filters to a number of multiview images prior to multiplexing, we conclude that, due to their increased bandwidth, the filters lead to visibly sharper 3-D images without increasing aliasing artifacts.

Dual DV or HDV camcorder setups are widely used to record stereoscopic video content. However, even when using a remote control to operate the camcorders synchronously, the number of recorded frames per scene is slightly different on the left and right tape. The different lengths make it impossible to play back the recorded content immediately. Up to now, both tapes had to be transferred to a hard disc and edited scene by scene. This paper presents a software-only solution to synchronize a pair of DV or HDV camcorders: Playback is assumed to be out of sync whenever a scene change does not occur at exactly the same time on the left and right tape. In such a case, the first tape is stopped until the scene change occurs on the second tape as well. Once both tapes have reached the scene change, playback on both drives is resumed. Detecting scene changes by means of image analysis is unreliable and CPU intensive. Consequently, we suggest a better method based on the recording date and time embedded in the compressed stream. To test the suggested solution, tape synchronization capabilities have been added to the Stereoscopic Multiplexer, a multiplexing solution for the Microsoft Windows platform.

In video systems, the introduction of 3D video might be the next revolution after the introduction of color. Nowadays multiview auto-stereoscopic displays are entering the market. Such displays offer various views at the same time. Depending on its positions, the viewers' eyes see different images. Hence, the viewers' left eye receives a signal that is different from what his right eye gets; this gives, provided the signals have been properly processed, the impression of depth. New auto-stereoscopic products use an image-plus-depth interface. On the other hand, a growing number of 3D productions from the entertainment industry use a stereo format. In this paper, we show how to compute depth from the stereo signal to comply with the display interface format. Furthermore, we present a realisation suitable for a real-time cost-effective implementation on an embedded media processor.

We developed an integral photography (IP) system that is suitable for small-lot production and is, in principle, applicable to animation. IP is an ideal 3D display method because users can see stereoscopic 3D images from arbitrary directions. However, IP is less popular than lenticular display using only the horizontal parallax, probably because the initial cost of designing and producing a fly's eye lens is very high. We used two technologies to solve this problem. First, we used two mutually perpendicular lenticular sheets instead of a fly's eye lens sheet. A lenticular sheet is much less expensive than a fly's eye lens because it is easier to produce. Second, we used the fractional view method, in which the ratio of lens pitch to pixel pitch is not limited to simple integer ratios, which means that no custom-made lenticular lens is necessary. However, the original fractional view method is applicable only to horizontal parallax. We made it applicable to both horizontal and vertical parallaxes by using two mutually perpendicular lenticular sheets. In addition, we developed a simple technique for generating dedicated synthesized images for IP.

We propose a new capturing system to realize capture of elemental images for an autostereoscopic display based on a one-dimensional integral imaging (1D-II) method. In order to realize a capturing system for the 1D-II display, capturing elemental images with fine pith and containing much horizontal parallax information with wide angle are important. The optical system composed of a cylindrical lens, a focusing lens and an imaging device can capture elemental images having these two features with scanning over an object. Furthermore, the system size can be small by adapting a compact scanning optical system of a copy machine. We captured 200 elemental images at a fine scan pitch of 0.5 mm. There were 92 horizontal pixels on each elemental image. The number of horizontal pixels correspond the number of parallaxes. The angle range of the captured parallaxes was 42 degrees. Using the autostereoscopic display based on the 1D-II method, the synthesized image can be observed to be a correct three-dimensional (3-D) image.

A lens array consisting of microlenses is normally used when shooting or displaying three-dimensional (3-D) images of a subject with use of the integral photography (IP) method. Elemental images that are produced through many microlenses (elemental lenses) are acquired during shooting, and spatial images using elemental images and lens array are produced during display. In this case, geometric distortions and chromatic aberrations of elemental lenses cause reconstructed images to deteriorate. Shooting and displaying have been done with use of a planar mirror instead of elemental lens in order to avoid these causes of deterioration. A pseudoscopic image where depth is reversed is produced in the structuring where a planar mirror is used. In this paper, an orthoscopic image that is produced by the use of a planar mirror array and gradient-index lens array has been confirmed. In addition, a method of avoiding pseudoscopic images by using differing mirror arrays in the shooting equipment and display setup has been proposed, and the confirmation of the effects through the experiment has been confirmed.

An enhanced algorithm of image mapping method is proposed for the computer-generated (CG) integral imaging system. Integral imaging is one of the attractive autostereoscopic three-dimensional (3D) display methods since it provides both vertical and horizontal parallaxes with full colors and it needs no special viewing aids on the observer. The CG integral imaging system uses the set of elemental images generated by computer graphics instead of the pickup process using the lens array. The process to obtain the set of elemental images using computer graphics is called image mapping. In this paper, we propose an enhanced image-mapping algorithm, named viewpoint vector rendering, to improve the speed of the elemental-image generation and to be more robust so that it is less affected by the system factors and the object image quality, as compared to the previous methods. Since the proposed algorithm can support the real-time generation of elemental images, it is possible to realize the CG integral imaging system applied for an interactive multimedia system. The feasibility and the efficiency of the proposed technique is verified and analyzed by mean of some experimental results.

We have built a 17" 2D-3D time sequential LCD autostereoscopic display with SXGA resolution, which does not have any special means for 2D-3D switching. The display is capable of simultaneous displaying 2D and 3D graphics without deterioration of visual performance of 2D images at a frame rate up to 120 Hz. Left and right sets of viewing zones are formed by a combination of a patterned retarder and a lenticular lens array placed behind the LCD panel. Right and left sets of viewing zones are switchable by polarization switch in synchronism with displaying left and right images. Application of patterned retarder provides smooth light distribution without dark regions between left and right viewing zones. To reduce dynamic crosstalk caused by slow switching of LCD cells a combination of Rresponse Time Acceleration (RTA) and scanning backlight have been applied

In this paper, we present an efficient method to synthesize 3D video from compressed 2D video. The 2D video is analyzed by computing frame-by-frame motion maps. For this computation, MPEG motion vectors extraction was performed. Using the extracted motion vector maps, the video undergoes analysis and the frames are segmented to provide object-wise depth ordering. The frames are then used to synthesize stereo pairs. This is performed by resampling the video frames on a grid that is governed by a corresponding depth-map. In order to improve the quality of the synthetic video, as well as to enable 2D viewing where 3D visualization is not possible, several techniques for image enhancement are used. In our test case, anaglyph projection was selected as the 3D visualization method, as the method is mostly suited to standard displays. The drawback of this method is ghosting artifacts. In our implementation we minimize these unwanted artifacts by modifying the computed depth-maps using non-linear transformations. Defocusing of one anaglyph color component was also used to counter such artifacts. Our results show that the suggested methods enable synthesis of high quality 3D videos in real-time.

Volumetric display systems based on three-dimensional (3-D) scanning of an inclined image are reported. An optical image of a two-dimensional (2-D) display device, which is placed obliquely in an optical imaging system, is moved laterally by an optical mirror scanner. Inclined cross-sectional images of a 3-D object are displayed on the 2-D display device in accordance with the position of the image plane. A locus of the moving image can be observed as a series of moving afterimages as a result of high-speed scanning. A 3-D real image is thus formed as a stack of 2-D cross-sectional images. This 3-D image can satisfy all the criteria for stereoscopic vision. A three-dimensional image consisting of 1024 × 768 × 150 pixels was formed by the constructed system using a digital micro mirror device. In addition, we propose a 3-D image transmission system, which can acquire the 3-D information of an object and display it as a volumetric image in real time. We constructed a high-speed 3-D measurement system based on the light-section method using an intelligent vision system, which can capture and process 1000 images per a millisecond. We demonstrate real-time volumetric image generation from the measured profile using the 3-D measurement system and the volumetric display system.

In this paper, we analyze the distortion of images acquired with a novel Ray-Space acquisition system. In case an arbitrary viewpoint picture is generated using the Ray-Space method, it is necessary to acquire dense ray data. Conventional methods for acquiring the Ray-Space data consist of using rotating stages or a camera array. We developed a system consisting of two parabolic mirrors, a synchronized galvanometric mirror and a high-speed camera. The principle is as follows; if an object is put in the bottom of the parabolic mirror, the ray which comes out of the object is imaged in the upper part, and form a real image. The galvanometer mirror is put on the position of a real image, and is made to scan horizontally. Images of the object of different angles (directions) are then possible to generate and are captured by the high-speed camera. By capturing many images at each scan, Ray-Space is therefore acquirable. However, distortion arises in the real image of the object formed. Consequently, distortion appears in the captured image. Therefore, it is necessary to correct the captured image to the right image. Here, we examine a method to generate corrected images from the acquired Ray-Space.

Ray-Space is categorized by Image-Based Rendering (IBR), thus generated views have photo-realistic quality. While this method has the performance of high quality imaging, this needs a lot of images or cameras. The reason why that is Ray-Space requires various direction's and position's views instead of 3D depth information. In this paper, we reduce that flood of information using view-centered ray interpolation. View-centered interpolation means estimating view dependent depth value (or disparity map) at generating view-point and interpolating that of pixel values using multi-view images and depth information. The combination of depth estimation and interpolation realizes the rendering photo-realistic images effectively. Unfortunately, however, if depth estimation is week or mistake, a lot of artifacts appear in creating images. Thus powerful depth estimation method is required. When we render the free viewpoint images video, we perform the depth estimation at every frame. Thus we want to keep a lid on computing cost. Our depth estimation method is based on dynamic programming (DP). This method optimizes and solves depth images at the weak matching area with high-speed performance. But scan-line noises become appeared because of the limit of DP. So, we perform the DP multi-direction pass and sum-up the result of multi-passed DPs. Our method fulfills the low computation cost and high depth estimation performance.

Object movie (OM) is a popular technique for producing interactive 3D artifacts because of its simplicity in production and it photo-realistic ability to present the artifacts. At the same time, many stereoscopic vision techniques are developed for a variety of applications. However, the traditional approach for generating binocular object movies require duplicate effort compared with monocular ones both in the process of acquisition and image processing. Therefore, we propose a framework to generate stereo OMs from monocular ones with the help of an automatically constructed 3D model from the monocular OM. Here, a new representation of the 3D model, named billboard clusters, is proposed for efficient generating binocular views. In order to obtain better results, a novel approach to extract view-independent texture is developed in this work. Besides, billboard clusters can be used to compress the storage capacity of OMs, and to perform relighting so that the binocular OMs can be well augmented into virtual environments with different lighting conditions. This paper describes the methods in detail and reports on its wide applications.

We have developed a new type of volumetric three-dimensional (3D) image display which has a 360-degree, 3D volume group-viewing capability without the use of any special viewing aids or goggles. In our system, a clear thin photopolymer sheet dissolving Lanthanide(III) complexes is used. The Lanthanide(III) complexes used in our system are Eu(TTA)₃ Phen, designed for 615nm luminescence (red) against an exciting light of 395nm. Arbitrary luminous point is identified by three dimensional control of the excitation position of the Lanthanide(III) complexes dissolved photopolymer sheet. The specific point (x,y,z) is excited by laser diode beam. The direction of the exciting laser beam is controlled by two galvano mirrors so as to excite the specific two-dimensional point (x,y). The depth direction (z) of the 3D object is specified by controlling two galvano mirrors in synchronization with a photopolymer sheet rotation. The 3D images are expressed as an aggregate of these luminous point. In the experiment, we observed static 3D objects of a triangle. We also observed 3D animation of a 3D Lissajous curve. Displayed 3D objects integrated with real background because rotating photopolymer sheet is transparent (transparent 3D display).

Virtual and Augmented Reality are developing rapidly: there is a multitude of environments and experiments in several laboratories using from simple HMD (Head-Mounted Display) visualization to more complex and expensive 6-wall projection CAVEs, and other systems. Still, there is not yet a clear emerging technology in this area, nor commercial applications based on such a technology are used in large scale. In addition to the fact that this is a relatively recent technology, there is little work to validate the utility and usability of Virtual and Augmented Reality environments when compared with the traditional desktop set-up. However, usability evaluation is crucial in order to design better systems that respond to the users' needs, as well as for identifying applications that might really gain from the use of such technologies. This paper presents a preliminary usability evaluation of a low-cost Virtual and Augmented Reality environment under development at the University of Aveiro, Portugal. The objective is to assess the difference between a traditional desktop set-up and a Virtual/Augmented Reality system based on a stereo HMD. Two different studies were performed: the first one was qualitative and some feedback was obtained from domain experts who used an Augmented Reality set-up as well as a desktop in different data visualization scenarios. The second study consisted in a controlled experiment meant to compare users' performances in a gaming scenario in a Virtual Reality environment and a desktop. The overall conclusion is that these technologies still have to overcome some hardware problems. However, for short periods of time and specific applications, Virtual and Augmented Reality seems to be a valid alternative since HMD interaction is intuitive and natural.

We report on an improvement of the voxel density of three-dimensional (3D) image display by spatially multiplexing fluxes in light-ray-flux reproduction method. In the basic light-ray-flux reproduction method, a color filter is projected by the use of an array of white-color point light sources in order to artificially generate a group of light rays corresponding to light scattered from an object, to thereby generate a 3D image. In the developed system, we used liquid crystal display (LCD) and pinhole array instead of color filter and white-color point light source array. The principle of this modified system is the same as the basic system. The light-ray fluxes are spatially multiplexed by rapidly changing the position of the pinholes. The 2D filter images displayed by the LCD are changed in synchronized with the position changes of the pinholes. In the experiment, position changes of the pinholes are realized by mechanically vibrating a slit mask array, which covers the pinhole array. We confirmed that the voxel density was improved to twice without the degradation of the viewing angle and the depth of the reconstructed 3D image.

In this paper, we propose a curved integral imaging system using an additional large-aperture lens. The additional largeaperture lens provides full-directional curvature effect and improves viewing angle compared with conventional system. The proposed system has a simple structure due to the use of well-fabricated conventional flat devices without any modification. A modified computer-generated pickup technique based on ABCD matrix is introduced to calculate elemental images of the proposed system. To show the usefulness of the proposed system, optical experiments are carried out and the results are presented. In addition, we analyze the enhanced viewing angle according to the object location and the limited image size theoretically.

Recently, many types of computer-generated stereograms (CGSs), i.e. various works of art produced by using computer are published for hobby and entertainment. It is said that activation of brain, improvement of visual eye sight, decrease of mental stress, effect of healing, etc. are expected when properly appreciating a kind of CGS as the stereoscopic view. There is a lot of information on the internet web site concerning all aspects of stereogram history, science, social organization, various types of stereograms, and free software for generating CGS. Generally, the CGS is classified into nine types: (1) stereo pair type, (2) anaglyph type, (3) repeated pattern type, (4) embedded type, (5) random dot stereogram (RDS), (6) single image stereogram (SIS), (7) united stereogram, (8) synthesized stereogram, and (9) mixed or multiple type stereogram. Each stereogram has advantages and disadvantages when viewing directly the stereogram with two eyes by training with a little patience. In this study, the characteristics of united, synthesized and mixed type stereograms, the role and composition of depth map image (DMI) called hidden image or picture, and the effect of irregular shift of texture pattern image called wall paper are discussed from the viewpoint of psychophysical estimation of 3D virtual depth and visual quality of virtual image by means of simultaneous observation in the case of the parallel viewing method.

In this paper, a novel resolution-enhanced three-dimensional (3-D) image correlator by use of computationally reconstructed integral images is proposed to extract accurate location data of 3-D objects. Elemental images of the target and reference objects are picked up by lenslet arrays and from which, high-resolution target and reference plane images are reconstructed at the output plane by using a computational integral imaging reconstruction technique. Then, through cross-correlations between the reconstructed reference and target plane images, 3-D location data of the target objects in a scene can be robustly extracted. To show the feasibility of the proposed method, some experiments are carried out and its results are presented as well.

We present a point based reconstruction and transmission pipeline for a collaborative tele-immersion system. Two or more users in different locations collaborate with each other in a shared, simulated environment as if they were in the same physical room. Each user perceives point-based models of distant users along with collaborative data like molecule models. Disparity maps, computed by a commercial stereo solution, are filtered and transformed into clouds of 3D points. The clouds are compressed and transmitted over the network to distant users. At the other side the clouds are decompressed and incorporated into the 3D scene. The viewpoint used to display the 3D scene is dependent on the position of the head of the user. Collaborative data is manipulated through natural hand gestures. We analyse the performance of the system in terms of computation time, latency and photo realistic quality of the reconstructed models.

We propose a method for real-time photorealistic stereo rendering of the natural phenomenon of fire. Applications include the use of virtual reality in fire fighting, military training, and entertainment. Rendering fire in real-time presents a challenge because of the transparency and non-static fluid-like behavior of fire. It is well known that, in general, methods that are effective for monoscopic rendering are not necessarily easily extended to stereo rendering because monoscopic methods often do not provide the depth information necessary to produce the parallax required for binocular disparity in stereoscopic rendering. We investigate the existing techniques used for monoscopic rendering of fire and discuss their suitability for extension to real-time stereo rendering. Methods include the use of precomputed textures, dynamic generation of textures, and rendering models resulting from the approximation of solutions of fluid dynamics equations through the use of ray-tracing algorithms. We have found that in order to attain real-time frame rates, our method based on billboarding is effective. Slicing is used to simulate depth. Texture mapping or 2D images are mapped onto polygons and alpha blending is used to treat transparency. We can use video recordings or prerendered high-quality images of fire as textures to attain photorealistic stereo.

Three-dimensional media is a unique and efficient means to virtually visit/observe objects that cannot be easily reached otherwise, like the International Space Station. The advent of auto-stereoscopic displays and stereo projection system is making the stereo media available to larger audiences than the traditional scientists and design engineers communities. It is foreseen that a major demand for 3D content shall come from the entertainment area. Taking advantage of the 6 months long permanence on the International Space Station of a colleague European Astronaut, Thomas Reiter, the Erasmus Centre uploaded to the ISS a newly developed, fully digital stereo camera, the Erasmus Recording Binocular. Testing the camera and its human interfaces in weightlessness, as well as accurately mapping the interior of the ISS are the main objectives of the experiment that has just been completed at the time of writing. The intent of this paper is to share with the readers the design challenges tackled in the development and operation of the ERB camera and highlight some of the future plans the Erasmus Centre team has in the pipeline.

A fundamental task of a virtual-environment system is to present images that change appropriately as the user's head moves. Latency produces registration error causing the scene to appear spatially unstable. To improve the spatial stability of the scene, we built a system that, immediately before scanout to a head-mounted raster display, selects a portion of each scanline from an image rendered at a wider display width. The pixel selection corrects for yaw head rotations and effectively reduces latency for yaw to the millisecond range. In informal evaluations, users consistently judged visual scenes more stable and reported no additional visual artifacts with horizontal scanline selection than the same system without. Scanline-selection hardware can be added to existing virtual-reality systems as an external device between the graphics card and the raster display.

In this paper, we propose a novel display method to realize a high-resolution image in a central visual field for a hyper-realistic head dome projector. The method uses image processing based on the characteristics of human vision, namely, high central visual acuity and low peripheral visual acuity, and pixel shift technology, which is one of the resolution-enhancing technologies for projectors. The projected image with our method is a fine wide-viewing-angle image with high definition in the central visual field. We evaluated the psychological effects of the projected images with our method in terms of sensation of reality. According to the result, we obtained 1.5 times higher resolution in the central visual field and a greater sensation of reality by using our method.

This paper presents a tangible mixed reality desktop that supports gesture-oriented interactions in 3D space. The system is based on computer vision techniques for hand and finger detection, without the need for attaching any devices to the user. The system consists of a pair of stereo cameras that point to a planar surface as the work bench. Using stereo triangulation, the 3D locations and directions of the user's fingers are detected and tracked in the space on and above the surface. Based on our 3D finger tracking technique, we design a few simple multi-finger gestural interactions for digital media management. The system provides a convenient and user-friendly way of manipulating virtual objects in 3D space and supports seamless interactions with physical objects.

This paper describes the research and development of a virtual reality visualization project "Passing excellence" about the world famous architectural ensemble "Kizhi". The Kizhi Pogost is located on an island in Lake Onega in northern Karelia in Russia. It is an authentic museum of an ancient wood building tradition which presents a unique artistic achievement. This ensemble preserves a concentration of masterpieces of the Russian heritage and is included in the List of Most Endangered Sites of the World Monuments Watch protected by World Heritage List of UNESCO. The project strives to create a unique virtual observation of the dynamics of the architectural changes of the museum area beginning from the 15th Century up to the 21st Century. The visualization is being created to restore the original architecture of Kizhi island based on the detailed photographs, architectural and geometric measurements, textural data, video surveys and resources from the Kizhi State Open-Air Museum archives. The project is being developed using Electro, an application development environment for the tiled display high-resolution graphics visualization system and can be shown on the virtual reality systems such as the GeoWall^TM and the C-Wall.

CytoViz is an artistic, real-time information visualization driven by statistical information gathered during gigabit network transfers to the Scalable Adaptive Graphical Environment (SAGE) at various events. Data streams are mapped to cellular organisms defining their structure and behavior as autonomous agents. Network bandwidth drives the growth of each entity and the latency defines its physics-based independent movements. The collection of entity is bound within the 3D representation of the local venue. This visual and animated metaphor allows the public to experience the complexity of high-speed network streams that are used in the scientific community. Moreover, CytoViz displays the presence of discoverable Bluetooth devices carried by nearby persons. The concept is to generate an event-specific, real-time visualization that creates informational 3D patterns based on actual local presence. The observed Bluetooth traffic is put in opposition of the wide-area networking traffic by overlaying 2D animations on top of the 3D world. Each device is mapped to an animation fading over time while displaying the name of the detected device and its unique physical address. CytoViz was publicly presented at two major international conferences in 2005 (iGrid2005 in San Diego, CA and SC05 in Seattle, WA).

It is the uniqueness of Virtual Reality as a medium that calls for the creation of hybrid realities which blur the finite boundaries between physical and digital existence. Virtual Reality's distinguishing features as an artistic medium embody a distinct form of aesthetics: it is a stereoscopic, immersive, interactive, performative, dynamic, and experiential medium. A Virtual Reality art piece manifests in multiple ways. It can present itself as an interactive virtual archetype, exploring concepts rendered from different perspectives, and as an impetus to challenge the platform's capabilities, not only theoretically as an artistic practice, but also by calling for the instantiation of authoring tools for the development of virtual reality experiences. The paradigm presented in this paper is a Virtual Reality art piece, called skin, 2006, developed on Electro, which is an open-source cross-platform development environment. skin, 2006, is an interactive hypersteroscopic high-definition audiovisual installation that explores a dialogue between physical and digital senses of "touch".