An HTML Tool for Production of Interactive Stereoscopic Compositions.

Science.gov (United States)

Chistyakov, Alexey; Soto, Maria Teresa; Martí, Enric; Carrabina, Jordi

2016-12-01

The benefits of stereoscopic vision in medical applications were appreciated and have been thoroughly studied for more than a century. The usage of the stereoscopic displays has a proven positive impact on performance in various medical tasks. At the same time the market of 3D-enabled technologies is blooming. New high resolution stereo cameras, TVs, projectors, monitors, and head mounted displays become available. This equipment, completed with a corresponding application program interface (API), could be relatively easy implemented in a system. Such complexes could open new possibilities for medical applications exploiting the stereoscopic depth. This work proposes a tool for production of interactive stereoscopic graphical user interfaces, which could represent a software layer for web-based medical systems facilitating the stereoscopic effect. Further the tool's operation mode and the results of the conducted subjective and objective performance tests will be exposed.

Interlopers 3D: experiences designing a stereoscopic game

Science.gov (United States)

Weaver, James; Holliman, Nicolas S.

2014-03-01

Background In recent years 3D-enabled televisions, VR headsets and computer displays have become more readily available in the home. This presents an opportunity for game designers to explore new stereoscopic game mechanics and techniques that have previously been unavailable in monocular gaming. Aims To investigate the visual cues that are present in binocular and monocular vision, identifying which are relevant when gaming using a stereoscopic display. To implement a game whose mechanics are so reliant on binocular cues that the game becomes impossible or at least very difficult to play in non-stereoscopic mode. Method A stereoscopic 3D game was developed whose objective was to shoot down advancing enemies (the Interlopers) before they reached their destination. Scoring highly required players to make accurate depth judgments and target the closest enemies first. A group of twenty participants played both a basic and advanced version of the game in both monoscopic 2D and stereoscopic 3D. Results The results show that in both the basic and advanced game participants achieved higher scores when playing in stereoscopic 3D. The advanced game showed that by disrupting the depth from motion cue the game became more difficult in monoscopic 2D. Results also show a certain amount of learning taking place over the course of the experiment, meaning that players were able to score higher and finish the game faster over the course of the experiment. Conclusions Although the game was not impossible to play in monoscopic 2D, participants results show that it put them at a significant disadvantage when compared to playing in stereoscopic 3D.

Dream Home: a multiview stereoscopic interior design system

Science.gov (United States)

Hsiao, Fu-Jen; Teng, Chih-Jen; Lin, Chung-Wei; Luo, An-Chun; Yang, Jinn-Cherng

2010-01-01

In this paper, a novel multi-view stereoscopic interior design system, "Dream Home", has been developed to bring users new interior design experience. Different than other interior design system before, we put emphasis on its intuitive manipulation and multi-view stereoscopic visualization in real time. Users can do their own interior design just using their hands and eyes without any difficulty. They manipulate furniture cards directly as they wish to setup their living room in the model house task space, get the multi-view 3D visual feedback instantly, and re-adjust cards until they are satisfied. No special skills are required, and you can explore your design talent arbitrarily. We hope that "Dream Home" will make interior design more user-friendly, more intuitive, and more vivid.

Evaluating methods for controlling depth perception in stereoscopic cinematography

Science.gov (United States)

Sun, Geng; Holliman, Nick

2009-02-01

Existing stereoscopic imaging algorithms can create static stereoscopic images with perceived depth control function to ensure a compelling 3D viewing experience without visual discomfort. However, current algorithms do not normally support standard Cinematic Storytelling techniques. These techniques, such as object movement, camera motion, and zooming, can result in dynamic scene depth change within and between a series of frames (shots) in stereoscopic cinematography. In this study, we empirically evaluate the following three types of stereoscopic imaging approaches that aim to address this problem. (1) Real-Eye Configuration: set camera separation equal to the nominal human eye interpupillary distance. The perceived depth on the display is identical to the scene depth without any distortion. (2) Mapping Algorithm: map the scene depth to a predefined range on the display to avoid excessive perceived depth. A new method that dynamically adjusts the depth mapping from scene space to display space is presented in addition to an existing fixed depth mapping method. (3) Depth of Field Simulation: apply Depth of Field (DOF) blur effect to stereoscopic images. Only objects that are inside the DOF are viewed in full sharpness. Objects that are far away from the focus plane are blurred. We performed a human-based trial using the ITU-R BT.500-11 Recommendation to compare the depth quality of stereoscopic video sequences generated by the above-mentioned imaging methods. Our results indicate that viewers' practical 3D viewing volumes are different for individual stereoscopic displays and viewers can cope with much larger perceived depth range in viewing stereoscopic cinematography in comparison to static stereoscopic images. Our new dynamic depth mapping method does have an advantage over the fixed depth mapping method in controlling stereo depth perception. The DOF blur effect does not provide the expected improvement for perceived depth quality control in 3D cinematography

Stereoscopic display in a slot machine

Science.gov (United States)

Laakso, M.

2012-03-01

This paper reports the results of a user trial with a slot machine equipped with a stereoscopic display. The main research question was to find out what kind of added value does stereoscopic 3D (S-3D) bring to slot games? After a thorough literature survey, a novel gaming platform was designed and implemented. Existing multi-game slot machine "Nova" was converted to "3DNova" by replacing the monitor with an S-3D display and converting six original games to S-3D format. To evaluate the system, several 3DNova machines were put available for players for four months. Both qualitative and quantitative analysis was carried out from statistical values, questionnaires and observations. According to the results, people find the S-3D concept interesting but the technology is not optimal yet. Young adults and adults were fascinated by the system, older people were more cautious. Especially the need to wear stereoscopic glasses provide a challenge; ultimate system would probably use autostereoscopic technology. Also the games should be designed to utilize its full power. The main contributions of this paper are lessons learned from creating an S-3D slot machine platform and novel information about human factors related to stereoscopic slot machine gaming.

Stereoscopic 3D video games and their effects on engagement

Science.gov (United States)

Hogue, Andrew; Kapralos, Bill; Zerebecki, Chris; Tawadrous, Mina; Stanfield, Brodie; Hogue, Urszula

2012-03-01

With television manufacturers developing low-cost stereoscopic 3D displays, a large number of consumers will undoubtedly have access to 3D-capable televisions at home. The availability of 3D technology places the onus on content creators to develop interesting and engaging content. While the technology of stereoscopic displays and content generation are well understood, there are many questions yet to be answered surrounding its effects on the viewer. Effects of stereoscopic display on passive viewers for film are known, however video games are fundamentally different since the viewer/player is actively (rather than passively) engaged in the content. Questions of how stereoscopic viewing affects interaction mechanics have previously been studied in the context of player performance but very few have attempted to quantify the player experience to determine whether stereoscopic 3D has a positive or negative influence on their overall engagement. In this paper we present a preliminary study of the effects stereoscopic 3D have on player engagement in video games. Participants played a video game in two conditions, traditional 2D and stereoscopic 3D and their engagement was quantified using a previously validated self-reporting tool. The results suggest that S3D has a positive effect on immersion, presence, flow, and absorption.

Use of camera drive in stereoscopic display of learning contents of introductory physics

Science.gov (United States)

Matsuura, Shu

2011-03-01

Simple 3D physics simulations with stereoscopic display were created for a part of introductory physics e-Learning. First, cameras to see the 3D world can be made controllable by the user. This enabled to observe the system and motions of objects from any position in the 3D world. Second, cameras were made attachable to one of the moving object in the simulation so as to observe the relative motion of other objects. By this option, it was found that users perceive the velocity and acceleration more sensibly on stereoscopic display than on non-stereoscopic 3D display. Simulations were made using Adobe Flash ActionScript, and Papervison 3D library was used to render the 3D models in the flash web pages. To display the stereogram, two viewports from virtual cameras were displayed in parallel in the same web page. For observation of stereogram, the images of two viewports were superimposed by using 3D stereogram projection box (T&TS CO., LTD.), and projected on an 80-inch screen. The virtual cameras were controlled by keyboard and also by Nintendo Wii remote controller buttons. In conclusion, stereoscopic display offers learners more opportunities to play with the simulated models, and to perceive the characteristics of motion better.

Measuring system with stereoscopic x-ray television for accurate diagnosis

International Nuclear Information System (INIS)

Iwasaki, K.; Shimizu, S.

1987-01-01

X-ray stereoscopic television is diagnostically effective. The authors invented a measuring system using stereoscopic television whereby the coordinates of any two points and their separation can be measured in real time without physical contact. For this purpose, the distances between the two foci of the tube and between the tube and image intensifier were entered into a microcomputer beforehand, and any two points on the CRT stereoscopic image can be defined through the stereoscopic spectacles. The coordinates and distance are then displayed on the CRT monitor. By this means, measurements such as distance between vessels and size of organs are easily made

Matte painting in stereoscopic synthetic imagery

Science.gov (United States)

Eisenmann, Jonathan; Parent, Rick

2010-02-01

While there have been numerous studies concerning human perception in stereoscopic environments, rules of thumb for cinematography in stereoscopy have not yet been well-established. To that aim, we present experiments and results of subject testing in a stereoscopic environment, similar to that of a theater (i.e. large flat screen without head-tracking). In particular we wish to empirically identify thresholds at which different types of backgrounds, referred to in the computer animation industry as matte paintings, can be used while still maintaining the illusion of seamless perspective and depth for a particular scene and camera shot. In monoscopic synthetic imagery, any type of matte painting that maintains proper perspective lines, depth cues, and coherent lighting and textures saves in production costs while still maintaining the illusion of an alternate cinematic reality. However, in stereoscopic synthetic imagery, a 2D matte painting that worked in monoscopy may fail to provide the intended illusion of depth because the viewer has added depth information provided by stereopsis. We intend to observe two stereoscopic perceptual thresholds in this study which will provide practical guidelines indicating when to use each of three types of matte paintings. We ran subject tests in two virtual testing environments, each with varying conditions. Data were collected showing how the choices of the users matched the correct response, and the resulting perceptual threshold patterns are discussed below.

Usability of stereoscopic view in teleoperation

Science.gov (United States)

Boonsuk, Wutthigrai

2015-03-01

Recently, there are tremendous growths in the area of 3D stereoscopic visualization. The 3D stereoscopic visualization technology has been used in a growing number of consumer products such as the 3D televisions and the 3D glasses for gaming systems. This technology refers to the idea that human brain develops depth of perception by retrieving information from the two eyes. Our brain combines the left and right images on the retinas and extracts depth information. Therefore, viewing two video images taken at slightly distance apart as shown in Figure 1 can create illusion of depth [8]. Proponents of this technology argue that the stereo view of 3D visualization increases user immersion and performance as more information is gained through the 3D vision as compare to the 2D view. However, it is still uncertain if additional information gained from the 3D stereoscopic visualization can actually improve user performance in real world situations such as in the case of teleoperation.

Psychometric Assessment of Stereoscopic Head-Mounted Displays

Science.gov (United States)

2016-06-29

Journal Article 3. DATES COVERED (From – To) Jan 2015 - Dec 2015 4. TITLE AND SUBTITLE PSYCHOMETRIC ASSESSMENT OF STEREOSCOPIC HEAD- MOUNTED DISPLAYS...to render an immersive three-dimensional constructive environment. The purpose of this effort was to quantify the impact of aircrew vision on an...simulated tasks requiring precise depth discrimination. This work will provide an example validation method for future stereoscopic virtual immersive

Stereoscopic Integrated Imaging Goggles for Multimodal Intraoperative Image Guidance.

Directory of Open Access Journals (Sweden)

Christopher A Mela

Full Text Available We have developed novel stereoscopic wearable multimodal intraoperative imaging and display systems entitled Integrated Imaging Goggles for guiding surgeries. The prototype systems offer real time stereoscopic fluorescence imaging and color reflectance imaging capacity, along with in vivo handheld microscopy and ultrasound imaging. With the Integrated Imaging Goggle, both wide-field fluorescence imaging and in vivo microscopy are provided. The real time ultrasound images can also be presented in the goggle display. Furthermore, real time goggle-to-goggle stereoscopic video sharing is demonstrated, which can greatly facilitate telemedicine. In this paper, the prototype systems are described, characterized and tested in surgeries in biological tissues ex vivo. We have found that the system can detect fluorescent targets with as low as 60 nM indocyanine green and can resolve structures down to 0.25 mm with large FOV stereoscopic imaging. The system has successfully guided simulated cancer surgeries in chicken. The Integrated Imaging Goggle is novel in 4 aspects: it is (a the first wearable stereoscopic wide-field intraoperative fluorescence imaging and display system, (b the first wearable system offering both large FOV and microscopic imaging simultaneously,

Interactive floating windows: a new technique for stereoscopic video games

Science.gov (United States)

Zerebecki, Chris; Stanfield, Brodie; Tawadrous, Mina; Buckstein, Daniel; Hogue, Andrew; Kapralos, Bill

2012-03-01

The film industry has a long history of creating compelling experiences in stereoscopic 3D. Recently, the video game as an artistic medium has matured into an effective way to tell engaging and immersive stories. Given the current push to bring stereoscopic 3D technology into the consumer market there is considerable interest to develop stereoscopic 3D video games. Game developers have largely ignored the need to design their games specifically for stereoscopic 3D and have thus relied on automatic conversion and driver technology. Game developers need to evaluate solutions used in other media, such as film, to correct perceptual problems such as window violations, and modify or create new solutions to work within an interactive framework. In this paper we extend the dynamic floating window technique into the interactive domain enabling the player to position a virtual window in space. Interactively changing the position, size, and the 3D rotation of the virtual window, objects can be made to 'break the mask' dramatically enhancing the stereoscopic effect. By demonstrating that solutions from the film industry can be extended into the interactive space, it is our hope that this initiates further discussion in the game development community to strengthen their story-telling mechanisms in stereoscopic 3D games.

3D Stereoscopic Visualization of Fenestrated Stent Grafts

International Nuclear Information System (INIS)

Sun Zhonghua; Squelch, Andrew; Bartlett, Andrew; Cunningham, Kylie; Lawrence-Brown, Michael

2009-01-01

The purpose of this study was to present a technique of stereoscopic visualization in the evaluation of patients with abdominal aortic aneurysm treated with fenestrated stent grafts compared with conventional 2D visualizations. Two patients with abdominal aortic aneurysm undergoing fenestrated stent grafting were selected for inclusion in the study. Conventional 2D views including axial, multiplanar reformation, maximum-intensity projection, and volume rendering and 3D stereoscopic visualizations were assessed by two experienced reviewers independently with regard to the treatment outcomes of fenestrated repair. Interobserver agreement was assessed with Kendall's W statistic. Multiplanar reformation and maximum-intensity projection visualizations were scored the highest in the evaluation of parameters related to the fenestrated stent grafting, while 3D stereoscopic visualization was scored as valuable in the evaluation of appearance (any distortions) of the fenestrated stent. Volume rendering was found to play a limited role in the follow-up of fenestrated stent grafting. 3D stereoscopic visualization adds additional information that assists endovascular specialists to identify any distortions of the fenestrated stents when compared with 2D visualizations.

Using mental rotation to evaluate the benefits of stereoscopic displays

Science.gov (United States)

Aitsiselmi, Y.; Holliman, N. S.

2009-02-01

Context: The idea behind stereoscopic displays is to create the illusion of depth and this concept could have many practical applications. A common spatial ability test involves mental rotation. Therefore a mental rotation task should be easier if being undertaken on a stereoscopic screen. Aim: The aim of this project is to evaluate stereoscopic displays (3D screen) and to assess whether they are better for performing a certain task than over a 2D display. A secondary aim was to perform a similar study but replicating the conditions of using a stereoscopic mobile phone screen. Method: We devised a spatial ability test involving a mental rotation task that participants were asked to complete on either a 3D or 2D screen. We also design a similar task to simulate the experience on a stereoscopic cell phone. The participants' error rate and response times were recorded. Using statistical analysis, we then compared the error rate and response times of the groups to see if there were any significant differences. Results: We found that the participants got better scores if they were doing the task on a stereoscopic screen as opposed to a 2D screen. However there was no statistically significant difference in the time it took them to complete the task. We also found similar results for 3D cell phone display condition. Conclusions: The results show that the extra depth information given by a stereoscopic display makes it easier to mentally rotate a shape as depth cues are readily available. These results could have many useful implications to certain industries.

Stereoscopic medical imaging collaboration system

Science.gov (United States)

Okuyama, Fumio; Hirano, Takenori; Nakabayasi, Yuusuke; Minoura, Hirohito; Tsuruoka, Shinji

2007-02-01

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.

High-Definition 3D Stereoscopic Microscope Display System for Biomedical Applications

Directory of Open Access Journals (Sweden)

Yoo Kwan-Hee

2010-01-01

Full Text Available Biomedical research has been performed by using advanced information techniques, and micro-high-quality stereo images have been used by researchers and/or doctors for various aims in biomedical research and surgery. To visualize the stereo images, many related devices have been developed. However, the devices are difficult to learn for junior doctors and demanding to supervise for experienced surgeons. In this paper, we describe the development of a high-definition (HD three-dimensional (3D stereoscopic imaging display system for operating a microscope or experimenting on animals. The system consists of a stereoscopic camera part, image processing device for stereoscopic video recording, and stereoscopic display. In order to reduce eyestrain and viewer fatigue, we use a preexisting stereo microscope structure and polarized-light stereoscopic display method that does not reduce the quality of the stereo images. The developed system can overcome the discomfort of the eye piece and eyestrain caused by use over a long period of time.

Stereoscopic game design and evaluation

Science.gov (United States)

Rivett, Joe; Holliman, Nicolas

2013-03-01

We report on a new game design where the goal is to make the stereoscopic depth cue sufficiently critical to success that game play should become impossible without using a stereoscopic 3D (S3D) display and, at the same time, we investigate whether S3D game play is affected by screen size. Before we detail our new game design we review previously unreported results from our stereoscopic game research over the last ten years at the Durham Visualisation Laboratory. This demonstrates that game players can achieve significantly higher scores using S3D displays when depth judgements are an integral part of the game. Method: We design a game where almost all depth cues, apart from the binocular cue, are removed. The aim of the game is to steer a spaceship through a series of oncoming hoops where the viewpoint of the game player is from above, with the hoops moving right to left across the screen towards the spaceship, to play the game it is essential to make decisive depth judgments to steer the spaceship through each oncoming hoop. To confound these judgements we design altered depth cues, for example perspective is reduced as a cue by varying the hoop's depth, radius and cross-sectional size. Results: Players were screened for stereoscopic vision, given a short practice session, and then played the game in both 2D and S3D modes on a seventeen inch desktop display, on average participants achieved a more than three times higher score in S3D than they achieved in 2D. The same experiment was repeated using a four metre S3D projection screen and similar results were found. Conclusions: Our conclusion is that games that use the binocular depth cue in decisive game judgements can benefit significantly from using an S3D display. Based on both our current and previous results we additionally conclude that display size, from cell-phone, to desktop, to projection display does not adversely affect player performance.

Traveling via Rome through the Stereoscope: Reality, Memory, and Virtual Travel

Directory of Open Access Journals (Sweden)

Douglas M. Klahr

2016-06-01

Full Text Available Underwood and Underwood’s 'Rome through the Stereoscope' of 1902 was a landmark in stereoscopic photography publishing, both as an intense, visually immersive experience and as a cognitively demanding exercise. The set consisted of a guidebook, forty-six stereographs, and five maps whose notations enabled the reader/viewer to precisely replicate the location and orientation of the photographer at each site. Combined with the extensive narrative within the guidebook, the maps and images guided its users through the city via forty-six sites, whether as an example of armchair travel or an actual travel companion. The user’s experience is examined and analyzed within the following parameters: the medium of stereoscopic photography, narrative, geographical imagination, and memory, bringing forth issues of movement, survey and route frames of reference, orientation, visualization, immersion, and primary versus secondary memories. 'Rome through the Stereoscope' was an example of virtual travel, and the process of fusing dual images into one — stereoscopic synthesis — further demarcated the experience as a virtual environment.

Efficient stereoscopic contents file format on the basis of ISO base media file format

Science.gov (United States)

Kim, Kyuheon; Lee, Jangwon; Suh, Doug Young; Park, Gwang Hoon

2009-02-01

A lot of 3D contents haven been widely used for multimedia services, however, real 3D video contents have been adopted for a limited applications such as a specially designed 3D cinema. This is because of the difficulty of capturing real 3D video contents and the limitation of display devices available in a market. However, diverse types of display devices for stereoscopic video contents for real 3D video contents have been recently released in a market. Especially, a mobile phone with a stereoscopic camera has been released in a market, which provides a user as a consumer to have more realistic experiences without glasses, and also, as a content creator to take stereoscopic images or record the stereoscopic video contents. However, a user can only store and display these acquired stereoscopic contents with his/her own devices due to the non-existence of a common file format for these contents. This limitation causes a user not share his/her contents with any other users, which makes it difficult the relevant market to stereoscopic contents is getting expanded. Therefore, this paper proposes the common file format on the basis of ISO base media file format for stereoscopic contents, which enables users to store and exchange pure stereoscopic contents. This technology is also currently under development for an international standard of MPEG as being called as a stereoscopic video application format.

A Review on Stereoscopic 3D: Home Entertainment for the Twenty First Century

Science.gov (United States)

Karajeh, Huda; Maqableh, Mahmoud; Masa'deh, Ra'ed

2014-12-01

In the last few years, stereoscopic developed very rapidly and employed in many different fields such as entertainment. Due to the importance of entertainment aspect of stereoscopic 3D (S3D) applications, a review of the current state of S3D development in entertainment technology is conducted. In this paper, a novel survey of the stereoscopic entertainment aspects is presented by discussing the significant development of a 3D cinema, the major development of 3DTV, the issues related to 3D video content and 3D video games. Moreover, we reviewed some problems that can be caused in the viewers' visual system from watching stereoscopic contents. Some stereoscopic viewers are not satisfied as they are frustrated from wearing glasses, have visual fatigue, complain from unavailability of 3D contents, and/or complain from some sickness. Therefore, we will discuss stereoscopic visual discomfort and to what extend the viewer will have an eye fatigue while watching 3D contents or playing 3D games. The suggested solutions in the literature for this problem are discussed.

Peculiarities of perception of stereoscopic radiation images in full colour

International Nuclear Information System (INIS)

Mamchev, G.V.

1994-01-01

The principles of coloring stereoscopic radiation images providing their three-dimensional structure distinguishing increase are discussed. The results of analytical and experimental studies dealing with estimation of the effect of stereoscopic image chromaticity on accuracy of metric operations realization in three-dimensional space are given. 5 refs., 1 fig., 1 tab

Is eye damage caused by stereoscopic displays?

Science.gov (United States)

Mayer, Udo; Neumann, Markus D.; Kubbat, Wolfgang; Landau, Kurt

2000-05-01

A normal developing child will achieve emmetropia in youth and maintain it. Thereby cornea, lens and axial length of the eye grow astonishingly coordinated. In the last years research has evidenced that this coordinated growing process is a visually controlled closed loop. The mechanism has been studied particularly in animals. It was found that the growth of the axial length of the eyeball is controlled by image focus information from the retina. It was shown that maladjustment can occur by this visually-guided growth control mechanism that result in ametropia. Thereby it has been proven that e.g. short-sightedness is not only caused by heredity, but is acquired under certain visual conditions. It is shown that these conditions are similar to the conditions of viewing stereoscopic displays where the normal accommodation convergence coupling is disjoint. An evaluation is given of the potential of damaging the eyes by viewing stereoscopic displays. Concerning this, different viewing methods for stereoscopic displays are evaluated. Moreover, clues are given how the environment and display conditions shall be set and what users shall be chosen to minimize the risk of eye damages.

Visual fatigue modeling for stereoscopic video shot based on camera motion

Science.gov (United States)

Shi, Guozhong; Sang, Xinzhu; Yu, Xunbo; Liu, Yangdong; Liu, Jing

2014-11-01

As three-dimensional television (3-DTV) and 3-D movie become popular, the discomfort of visual feeling limits further applications of 3D display technology. The cause of visual discomfort from stereoscopic video conflicts between accommodation and convergence, excessive binocular parallax, fast motion of objects and so on. Here, a novel method for evaluating visual fatigue is demonstrated. Influence factors including spatial structure, motion scale and comfortable zone are analyzed. According to the human visual system (HVS), people only need to converge their eyes to the specific objects for static cameras and background. Relative motion should be considered for different camera conditions determining different factor coefficients and weights. Compared with the traditional visual fatigue prediction model, a novel visual fatigue predicting model is presented. Visual fatigue degree is predicted using multiple linear regression method combining with the subjective evaluation. Consequently, each factor can reflect the characteristics of the scene, and the total visual fatigue score can be indicated according to the proposed algorithm. Compared with conventional algorithms which ignored the status of the camera, our approach exhibits reliable performance in terms of correlation with subjective test results.

Crosstalk evaluation in stereoscopic displays

NARCIS (Netherlands)

Wang, L.; Teunissen, C.; Tu, Yan; Chen, Li; Zhang, P.; Zhang, T.; Heynderickx, I.E.J.

2011-01-01

Substantial progress in liquid-crystal display and polarization film technology has enabled several types of stereoscopic displays. Despite all progress, some image distortions still exist in these 3-D displays, of which interocular crosstalk - light leakage of the image for one eye to the other eye

The development and evaluation of a stereoscopic television system for remote handling

International Nuclear Information System (INIS)

Dumbreck, A.A.; Murphy, S.P.; Smith, C.W.

1990-01-01

This paper describes the development and evaluation of a stereoscopic television system at Harwell Laboratory. The theory of stereo image geometry is outlined, and criteria for the matching of stereoscopic pictures are given. A stereoscopic television system designed for remote handling tasks has been produced, it provides two selectable angles of view and variable convergence, the display is viewed via polarizing spectacles. Evaluations have indicated improved performance with no problems of operator fatigue over a wide range of applications. (author)

Analysis of brain activity and response during monoscopic and stereoscopic visualization

Science.gov (United States)

Calore, Enrico; Folgieri, Raffaella; Gadia, Davide; Marini, Daniele

2012-03-01

Stereoscopic visualization in cinematography and Virtual Reality (VR) creates an illusion of depth by means of two bidimensional images corresponding to different views of a scene. This perceptual trick is used to enhance the emotional response and the sense of presence and immersivity of the observers. An interesting question is if and how it is possible to measure and analyze the level of emotional involvement and attention of the observers during a stereoscopic visualization of a movie or of a virtual environment. The research aims represent a challenge, due to the large number of sensorial, physiological and cognitive stimuli involved. In this paper we begin this research by analyzing possible differences in the brain activity of subjects during the viewing of monoscopic or stereoscopic contents. To this aim, we have performed some preliminary experiments collecting electroencephalographic (EEG) data of a group of users using a Brain- Computer Interface (BCI) during the viewing of stereoscopic and monoscopic short movies in a VR immersive installation.

Enhancement of stereoscopic comfort by fast control of frequency content with wavelet transform

Science.gov (United States)

Lemmer, Nicolas; Moreau, Guillaume; Fuchs, Philippe

2003-05-01

As the scope of virtual reality applications including stereoscopic imaging becomes wider, it is quite clear that not every designer of a VR application thinks of its constraints in order to make a correct use of stereo. Stereoscopic imagery though not required can be a useful tool for depth perception. It is possible to limit the depth of field as shown by Perrin who has also undertaken research on the link between the ability of fusing stereoscopic images (stereopsis) and local disparity and spatial frequency content. We will show how we can extend and enhance this work especially on the computational complexity point of view. The wavelet theory allows us to define a local spatial frequency and then a local measure of stereoscopic comfort. This measure is based on local spatial frequency and disparity as well as on the observations made by Woepking. Local comfort estimation allows us to propose several filtering methods to enhance this comfort. The idea to modify the images such as they check a "stereoscopic comfort condition" defined as a threshold for the stereoscopic comfort condition. More technically, we seek to limit high spatial frequency content when disparity is high thanks to the use of fast algorithms.

Stereoscopic Visualization of Diffusion Tensor Imaging Data: A Comparative Survey of Visualization Techniques

International Nuclear Information System (INIS)

Raslan, O.; Debnam, J.M.; Ketonen, L.; Kumar, A.J.; Schellingerhout, D.; Wang, J.

2013-01-01

Diffusion tensor imaging (DTI) data has traditionally been displayed as a gray scale functional anisotropy map (GSFM) or color coded orientation map (CCOM). These methods use black and white or color with intensity values to map the complex multidimensional DTI data to a two-dimensional image. Alternative visualization techniques, such as V m ax maps utilize enhanced graphical representation of the principal eigenvector by means of a headless arrow on regular non stereoscopic (VM) or stereoscopic display (VMS). A survey of clinical utility of patients with intracranial neoplasms was carried out by 8 neuro radiologists using traditional and nontraditional methods of DTI display. Pairwise comparison studies of 5 intracranial neoplasms were performed with a structured questionnaire comparing GSFM, CCOM, VM, and VMS. Six of 8 neuro radiologists favored V m ax maps over traditional methods of display (GSFM and CCOM). When comparing the stereoscopic (VMS) and the non-stereoscopic (VM) modes, 4 favored VMS, 2 favored VM, and 2 had no preference. In conclusion, processing and visualizing DTI data stereoscopically is technically feasible. An initial survey of users indicated that V m ax based display methodology with or without stereoscopic visualization seems to be preferred over traditional methods to display DTI data.

A analysis of differences between common types of 3D stereoscopic movie & TV technology

Directory of Open Access Journals (Sweden)

CHEN Shuangyin

2013-06-01

Full Text Available 3D stereoscopic movie & TV technology develops rapidly.It is spreading into common people's life day by day.In this thesis,the author analyzes 3D stereoscopic movie & TV technology thoroughly.By comparing and studying the different technical solutions of the stereoscopic photography and video recording,production process and playing back,the author generalizes the characteristics of various programs and analyzes their strength and weakness.Eventually,the thesis gives the specific application of existing technical solutions and the future development.At last,it puts improvement goals of 3D stereoscopic movie & TV technology and gives large future development.

Learning Receptive Fields and Quality Lookups for Blind Quality Assessment of Stereoscopic Images.

Science.gov (United States)

Shao, Feng; Lin, Weisi; Wang, Shanshan; Jiang, Gangyi; Yu, Mei; Dai, Qionghai

2016-03-01

Blind quality assessment of 3D images encounters more new challenges than its 2D counterparts. In this paper, we propose a blind quality assessment for stereoscopic images by learning the characteristics of receptive fields (RFs) from perspective of dictionary learning, and constructing quality lookups to replace human opinion scores without performance loss. The important feature of the proposed method is that we do not need a large set of samples of distorted stereoscopic images and the corresponding human opinion scores to learn a regression model. To be more specific, in the training phase, we learn local RFs (LRFs) and global RFs (GRFs) from the reference and distorted stereoscopic images, respectively, and construct their corresponding local quality lookups (LQLs) and global quality lookups (GQLs). In the testing phase, blind quality pooling can be easily achieved by searching optimal GRF and LRF indexes from the learnt LQLs and GQLs, and the quality score is obtained by combining the LRF and GRF indexes together. Experimental results on three publicly 3D image quality assessment databases demonstrate that in comparison with the existing methods, the devised algorithm achieves high consistent alignment with subjective assessment.

Recording stereoscopic 3D neurosurgery with a head-mounted 3D camera system.

Science.gov (United States)

Lee, Brian; Chen, Brian R; Chen, Beverly B; Lu, James Y; Giannotta, Steven L

2015-06-01

Stereoscopic three-dimensional (3D) imaging can present more information to the viewer and further enhance the learning experience over traditional two-dimensional (2D) video. Most 3D surgical videos are recorded from the operating microscope and only feature the crux, or the most important part of the surgery, leaving out other crucial parts of surgery including the opening, approach, and closing of the surgical site. In addition, many other surgeries including complex spine, trauma, and intensive care unit procedures are also rarely recorded. We describe and share our experience with a commercially available head-mounted stereoscopic 3D camera system to obtain stereoscopic 3D recordings of these seldom recorded aspects of neurosurgery. The strengths and limitations of using the GoPro(®) 3D system as a head-mounted stereoscopic 3D camera system in the operating room are reviewed in detail. Over the past several years, we have recorded in stereoscopic 3D over 50 cranial and spinal surgeries and created a library for education purposes. We have found the head-mounted stereoscopic 3D camera system to be a valuable asset to supplement 3D footage from a 3D microscope. We expect that these comprehensive 3D surgical videos will become an important facet of resident education and ultimately lead to improved patient care.

Stereoscopic image production: live, CGI, and integration

Science.gov (United States)

Criado, Enrique

2006-02-01

This paper shortly describes part of the experience gathered in more than 10 years of stereoscopic movie production, some of the most common problems found and the solutions, with more or less fortune, we applied to solve those problems. Our work is mainly focused in the entertainment market, theme parks, museums, and other cultural related locations and events. In our movies, we have been forced to develop our own devices to permit correct stereo shooting (stereoscopic rigs) or stereo monitoring (real-time), and to solve problems found with conventional film editing, compositing and postproduction software. Here, we discuss stereo lighting, monitoring, special effects, image integration (using dummies and more), stereo-camera parameters, and other general 3-D movie production aspects.

Effects of Intraluminal Thrombus on Patient-Specific Abdominal Aortic Aneurysm Hemodynamics via Stereoscopic Particle Image Velocity and Computational Fluid Dynamics Modeling

Science.gov (United States)

Chen, Chia-Yuan; Antón, Raúl; Hung, Ming-yang; Menon, Prahlad; Finol, Ender A.; Pekkan, Kerem

2014-01-01

The pathology of the human abdominal aortic aneurysm (AAA) and its relationship to the later complication of intraluminal thrombus (ILT) formation remains unclear. The hemodynamics in the diseased abdominal aorta are hypothesized to be a key contributor to the formation and growth of ILT. The objective of this investigation is to establish a reliable 3D flow visualization method with corresponding validation tests with high confidence in order to provide insight into the basic hemodynamic features for a better understanding of hemodynamics in AAA pathology and seek potential treatment for AAA diseases. A stereoscopic particle image velocity (PIV) experiment was conducted using transparent patient-specific experimental AAA models (with and without ILT) at three axial planes. Results show that before ILT formation, a 3D vortex was generated in the AAA phantom. This geometry-related vortex was not observed after the formation of ILT, indicating its possible role in the subsequent appearance of ILT in this patient. It may indicate that a longer residence time of recirculated blood flow in the aortic lumen due to this vortex caused sufficient shear-induced platelet activation to develop ILT and maintain uniform flow conditions. Additionally, two computational fluid dynamics (CFD) modeling codes (Fluent and an in-house cardiovascular CFD code) were compared with the two-dimensional, three-component velocity stereoscopic PIV data. Results showed that correlation coefficients of the out-of-plane velocity data between PIV and both CFD methods are greater than 0.85, demonstrating good quantitative agreement. The stereoscopic PIV study can be utilized as test case templates for ongoing efforts in cardiovascular CFD solver development. Likewise, it is envisaged that the patient-specific data may provide a benchmark for further studying hemodynamics of actual AAA, ILT, and their convolution effects under physiological conditions for clinical applications. PMID:24316984

Usage of stereoscopic visualization in the learning contents of rotational motion.

Science.gov (United States)

Matsuura, Shu

2013-01-01

Rotational motion plays an essential role in physics even at an introductory level. In addition, the stereoscopic display of three-dimensional graphics includes is advantageous for the presentation of rotational motions, particularly for depth recognition. However, the immersive visualization of rotational motion has been known to lead to dizziness and even nausea for some viewers. Therefore, the purpose of this study is to examine the onset of nausea and visual fatigue when learning rotational motion through the use of a stereoscopic display. The findings show that an instruction method with intermittent exposure of the stereoscopic display and a simplification of its visual components reduced the onset of nausea and visual fatigue for the viewers, which maintained the overall effect of instantaneous spatial recognition.

The development and evaluation of a stereoscopic television system for use in nuclear environments

International Nuclear Information System (INIS)

Dumbreck, A.A.; Murphy, S.P.

1987-01-01

This paper describes the development and evaluation of a stereoscopic TV system at Harwell Laboratory. The theory of stereo image geometry is outlined, and criteria for the matching of stereoscopic pictures are given. A stereoscopic TV system designed for remote handling tasks has been produced, it provides two selectable angles of view and variable convergence, the display is viewed via polarizing spectacles. Preliminary evaluations have indicated improved performance with no problems of operator fatigue

Efficient Stereoscopic Video Matching and Map Reconstruction for a Wheeled Mobile Robot

Directory of Open Access Journals (Sweden)

Oscar Montiel-Ross

2012-10-01

Full Text Available This paper presents a novel method to achieve stereoscopic vision for mobile robot (MR navigation with the advantage of not needing camera calibration for depth (distance estimation measurements. It uses the concept of the adaptive candidate matching window for stereoscopic correspondence for block matching, resulting in improvements in efficiency and accuracy. An average of 40% of time reduction in the calculation process is obtained. All the algorithms for navigation, including the stereoscopic vision module, were implemented using an original computer architecture for the Virtex 5 FPGA, where a distributed multicore processor system was embedded and coordinated using the Message Passing Interface.

Perceptual asymmetry reveals neural substrates underlying stereoscopic transparency.

Science.gov (United States)

Tsirlin, Inna; Allison, Robert S; Wilcox, Laurie M

2012-02-01

We describe a perceptual asymmetry found in stereoscopic perception of overlaid random-dot surfaces. Specifically, the minimum separation in depth needed to perceptually segregate two overlaid surfaces depended on the distribution of dots across the surfaces. With the total dot density fixed, significantly larger inter-plane disparities were required for perceptual segregation of the surfaces when the front surface had fewer dots than the back surface compared to when the back surface was the one with fewer dots. We propose that our results reflect an asymmetry in the signal strength of the front and back surfaces due to the assignment of the spaces between the dots to the back surface by disparity interpolation. This hypothesis was supported by the results of two experiments designed to reduce the imbalance in the neuronal response to the two surfaces. We modeled the psychophysical data with a network of inter-neural connections: excitatory within-disparity and inhibitory across disparity, where the spread of disparity was modulated according to figure-ground assignment. These psychophysical and computational findings suggest that stereoscopic transparency depends on both inter-neural interactions of disparity-tuned cells and higher-level processes governing figure ground segregation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Methodology for stereoscopic motion-picture quality assessment

Science.gov (United States)

Voronov, Alexander; Vatolin, Dmitriy; Sumin, Denis; Napadovsky, Vyacheslav; Borisov, Alexey

2013-03-01

Creating and processing stereoscopic video imposes additional quality requirements related to view synchronization. In this work we propose a set of algorithms for detecting typical stereoscopic-video problems, which appear owing to imprecise setup of capture equipment or incorrect postprocessing. We developed a methodology for analyzing the quality of S3D motion pictures and for revealing their most problematic scenes. We then processed 10 modern stereo films, including Avatar, Resident Evil: Afterlife and Hugo, and analyzed changes in S3D-film quality over the years. This work presents real examples of common artifacts (color and sharpness mismatch, vertical disparity and excessive horizontal disparity) in the motion pictures we processed, as well as possible solutions for each problem. Our results enable improved quality assessment during the filming and postproduction stages.

Subjective and objective measurements of visual fatigue induced by excessive disparities in stereoscopic images

Science.gov (United States)

Jung, Yong Ju; Kim, Dongchan; Sohn, Hosik; Lee, Seong-il; Park, Hyun Wook; Ro, Yong Man

2013-03-01

As stereoscopic displays have spread, it is important to know what really causes the visual fatigue and discomfort and what happens in the visual system in the brain behind the retina while viewing stereoscopic 3D images on the displays. In this study, functional magnetic resonance imaging (fMRI) was used for the objective measurement to assess the human brain regions involved in the processing of the stereoscopic stimuli with excessive disparities. Based on the subjective measurement results, we selected two subsets of comfort videos and discomfort videos in our dataset. Then, a fMRI experiment was conducted with the subsets of comfort and discomfort videos in order to identify which brain regions activated while viewing the discomfort videos in a stereoscopic display. We found that, when viewing a stereoscopic display, the right middle frontal gyrus, the right inferior frontal gyrus, the right intraparietal lobule, the right middle temporal gyrus, and the bilateral cuneus were significantly activated during the processing of excessive disparities, compared to those of small disparities (< 1 degree).

Clinical Assessment of a New Stereoscopic Digital Angiography System

International Nuclear Information System (INIS)

Moll, Thierry; Douek, Philippe; Finet, Gerard; Turjman, Francis; Picard, Catherine; Revel, Didier; Amiel, Michel

1998-01-01

Purpose: To assess the clinical feasibility of an experimental modified angiographic system capable of real-time digital stereofluoroscopy and stereography in X-ray angiography, using a twin-focus tube and a stereoscopic monitor. Methods: We report the experience obtained in 37 patients with a well-documented examination. The patients were examined for coronary angiography (11 cases), aortography (7 cases), pulmonary angiography (6 cases), inferior vena cava filter placement (2 cases), and cerebral angiography (11 cases). Six radiologists were asked to use stereoscopic features for fluoroscopy and angiography. A questionnaire was designed to record their subjective evaluation of stereoscopic image quality, ergonomics of the system, and its medical interest. Results: Stereofluoroscopy was successfully used in 25 of 37 cases; diplopia and/or ghost images were reported in 6 cases. It was helpful for aortic catheterization in 10 cases and for selective catheterization in 5 cases. In stereoangiography, depth was easily and accurately perceived in 27 of 37 cases; diplopia and/or ghost images were reported in 4 cases. A certain gain in the three-dimensional evaluation of the anatomy and relation between vessels and lesions was noted. As regards ergonomic considerations, polarized spectacles were not considered cumbersome. Visual fatigue and additional work were variously reported. Stereoshift tuning before X-ray acquisition was not judged to be a limiting factor. Conclusion: A twin-focus X-ray tube and a polarized shutter for stereoscopic display allowed effective real-time three-dimensional perception of angiographic images. Our clinical study suggests no clear medical interest for diagnostic examinations, but the field of interventional radiology needs to be investigated

Teaching-learning: stereoscopic 3D versus Traditional methods in Mexico City.

Science.gov (United States)

Mendoza Oropeza, Laura; Ortiz Sánchez, Ricardo; Ojeda Villagómez, Raúl

2015-01-01

In the UNAM Faculty of Odontology, we use a stereoscopic 3D teaching method that has grown more common in the last year, which makes it important to know whether students can learn better with this strategy. The objective of the study is to know, if the 4th year students of the bachelor's degree in dentistry learn more effectively with the use of stereoscopic 3D than the traditional method in Orthodontics. first, we selected the course topics, to be used for both methods; the traditional method using projection of slides and for the stereoscopic third dimension, with the use of videos in digital stereo projection (seen through "passive" polarized 3D glasses). The main topic was supernumerary teeth, including and diverted from their guide eruption. Afterwards we performed an exam on students, containing 24 items, validated by expert judgment in Orthodontics teaching. The results of the data were compared between the two educational methods for determined effectiveness using the model before and after measurement with the statistical package SPSS 20 version. The results presented for the 9 groups of undergraduates in dentistry, were collected with a total of 218 students for 3D and traditional methods, we found in a traditional method a mean 4.91, SD 1.4752 in the pretest and X=6.96, SD 1.26622, St Error 0.12318 for the posttest. The 3D method had a mean 5.21, SD 1.996779 St Error 0.193036 for the pretest X= 7.82, SD =0.963963, St Error 0.09319 posttest; the analysis of Variance between groups F= 5.60 Prob > 0.0000 and Bartlett's test for equal variances 21.0640 Prob > chi2 = 0.007. These results show that the student's learning in 3D means a significant improvement as compared to the traditional teaching method and having a strong association between the two methods. The findings suggest that the stereoscopic 3D method lead to improved student learning compared to traditional teaching.

Digital stereoscopic convergence where video games and movies for the home user meet

Science.gov (United States)

Schur, Ethan

2009-02-01

Today there is a proliferation of stereoscopic 3D display devices, 3D content, and 3D enabled video games. As we in the S-3D community bring stereoscopic 3D to the home user we have a real opportunity of using stereoscopic 3D to bridge the gap between exciting immersive games and home movies. But to do this, we cannot limit ourselves to current conceptions of gaming and movies. We need, for example, to imagine a movie that is fully rendered using avatars in a stereoscopic game environment. Or perhaps to imagine a pervasive drama where viewers can play too and become an essential part of the drama - whether at home or on the go on a mobile platform. Stereoscopic 3D is the "glue" that will bind these video and movie concepts together. As users feel more immersed, the lines between current media will blur. This means that we have the opportunity to shape the way that we, as humans, view and interact with each other, our surroundings and our most fundamental art forms. The goal of this paper is to stimulate conversation and further development on expanding the current gaming and home theatre infrastructures to support greatly-enhanced experiential entertainment.

A novel no-reference objective stereoscopic video quality assessment method based on visual saliency analysis

Science.gov (United States)

Yang, Xinyan; Zhao, Wei; Ye, Long; Zhang, Qin

2017-07-01

This paper proposes a no-reference objective stereoscopic video quality assessment method with the motivation that making the effect of objective experiments close to that of subjective way. We believe that the image regions with different visual salient degree should not have the same weights when designing an assessment metric. Therefore, we firstly use GBVS algorithm to each frame pairs and separate both the left and right viewing images into the regions with strong, general and week saliency. Besides, local feature information like blockiness, zero-crossing and depth are extracted and combined with a mathematical model to calculate a quality assessment score. Regions with different salient degree are assigned with different weights in the mathematical model. Experiment results demonstrate the superiority of our method compared with the existed state-of-the-art no-reference objective Stereoscopic video quality assessment methods.

A stereoscopic television system for reactor inspection

International Nuclear Information System (INIS)

Friend, D.B.; Jones, A.

1980-03-01

A stereoscopic television system suitable for reactor inspection has been developed. Right and left eye views, obtained from two conventional black and white cameras, are displayed by the anaglyph technique and observers wear appropriately coloured viewing spectacles. All camera functions, such as zoom, focus and toe-in are remotely controlled. A laboratory experiment is described which demonstrates the increase in spatial awareness afforded by the use of stereo television and illustrates its potential in the supervision of remote handling tasks. Typical depth resolutions of 3mm at 1m and 10mm at 2m have been achieved with the reactor instrument. Trials undertaken during routine inspection at Oldbury Power Station in June 1978 are described. They demonstrate that stereoscopic television can indeed improve the convenience of remote handling and that the added display realism is beneficial in visual inspection. (author)

In-line phase-contrast stereoscopic X-ray imaging for radiological purposes: An initial experimental study

International Nuclear Information System (INIS)

Siegbahn, E.A.; Coan, P.; Zhou, S.-A.; Bravin, A.; Brahme, A.

2011-01-01

We report results from a pilot study in which the in-line propagation-based phase-contrast imaging technique is combined with the stereoscopic method. Two phantoms were imaged at several sample-detector distances using monochromatic, 30 keV, X-rays. High contrast- and spatial-resolution phase-contrast stereoscopic pairs of X-ray images were constructed using the anaglyph approach and a vivid stereoscopic effect was demonstrated. On the other hand, images of the same phantoms obtained with a shorter sample-to-detector distance, but otherwise the same experimental conditions (i.e. the same X-ray energy and absorbed radiation dose), corresponding to the conventional attenuation-based imaging mode, hardly revealed stereoscopic effects because of the lower image contrast produced. These results have confirmed our hypothesis that stereoscopic X-ray images of samples with objects composed of low-atomic-number elements are considerably improved if phase-contrast imaging is used. It is our belief that the high-resolution phase-contrast stereoscopic method will be a valuable new medical imaging tool for radiologists and that it will be of help to enhance the diagnostic capability in the examination of patients in future clinical practice, even though further efforts will be needed to optimize the system performance.

Interactive and Stereoscopic Hybrid 3D Viewer of Radar Data with Gesture Recognition

Science.gov (United States)

Goenetxea, Jon; Moreno, Aitor; Unzueta, Luis; Galdós, Andoni; Segura, Álvaro

This work presents an interactive and stereoscopic 3D viewer of weather information coming from a Doppler radar. The hybrid system shows a GIS model of the regional zone where the radar is located and the corresponding reconstructed 3D volume weather data. To enhance the immersiveness of the navigation, stereoscopic visualization has been added to the viewer, using a polarized glasses based system. The user can interact with the 3D virtual world using a Nintendo Wiimote for navigating through it and a Nintendo Wii Nunchuk for giving commands by means of hand gestures. We also present a dynamic gesture recognition procedure that measures the temporal advance of the performed gesture postures. Experimental results show how dynamic gestures are effectively recognized so that a more natural interaction and immersive navigation in the virtual world is achieved.

Stereoscopic Three-Dimensional Visualization Applied to Multimodal Brain Images: Clinical Applications and a Functional Connectivity Atlas.

Directory of Open Access Journals (Sweden)

Gonzalo M Rojas

2014-11-01

Full Text Available Effective visualization is central to the exploration and comprehension of brain imaging data. While MRI data are acquired in three-dimensional space, the methods for visualizing such data have rarely taken advantage of three-dimensional stereoscopic technologies. We present here results of stereoscopic visualization of clinical data, as well as an atlas of whole-brain functional connectivity. In comparison with traditional 3D rendering techniques, we demonstrate the utility of stereoscopic visualizations to provide an intuitive description of the exact location and the relative sizes of various brain landmarks, structures and lesions. In the case of resting state fMRI, stereoscopic 3D visualization facilitated comprehension of the anatomical position of complex large-scale functional connectivity patterns. Overall, stereoscopic visualization improves the intuitive visual comprehension of image contents, and brings increased dimensionality to visualization of traditional MRI data, as well as patterns of functional connectivity.

The Role of Amodal Surface Completion in Stereoscopic Transparency

Science.gov (United States)

Anderson, Barton L.; Schmid, Alexandra C.

2012-01-01

Previous work has shown that the visual system can decompose stereoscopic textures into percepts of inhomogeneous transparency. We investigate whether this form of layered image decomposition is shaped by constraints on amodal surface completion. We report a series of experiments that demonstrate that stereoscopic depth differences are easier to discriminate when the stereo images generate a coherent percept of surface color, than when images require amodally integrating a series of color changes into a coherent surface. Our results provide further evidence for the intimate link between the segmentation processes that occur in conditions of transparency and occlusion, and the interpolation processes involved in the formation of amodally completed surfaces. PMID:23060829

Visual discomfort in stereoscopic displays : a review

NARCIS (Netherlands)

Lambooij, M.T.M.; IJsselsteijn, W.A.; Heynderickx, I.E.J.; Woods, A.J.; Merritt, J.O.; Bolas, M.T.; McDowall, I.E.

2007-01-01

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

Visual discomfort in stereoscopic dsplays : A review

NARCIS (Netherlands)

Lambooij, M.T.M.; IJsselsteijn, W.; Heynderickx, I.

2007-01-01

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

Stereoscopic 3D display with dynamic optical correction for recovering from asthenopia

Science.gov (United States)

Shibata, Takashi; Kawai, Takashi; Otsuki, Masaki; Miyake, Nobuyuki; Yoshihara, Yoshihiro; Iwasaki, Tsuneto

2005-03-01

The purpose of this study was to consider a practical application of a newly developed stereoscopic 3-D display that solves the problem of discrepancy between accommodation and convergence. The display uses dynamic optical correction to reduce the discrepancy, and can present images as if they are actually remote objects. The authors thought the display may assist in recovery from asthenopia, which is often caused when the eyes focus on a nearby object for a long time, such as in VDT (Visual Display Terminal) work. In general, recovery from asthenopia, and especially accommodative asthenopia, is achieved by focusing on distant objects. In order to verify this hypothesis, the authors performed visual acuity tests using Landolt rings before and after presenting stereoscopic 3-D images, and evaluated the degree of recovery from asthenopia. The experiment led to three main conclusions: (1) Visual acuity rose after viewing stereoscopic 3-D images on the developed display. (2) Recovery from asthenopia was particularly effective for the dominant eye in comparison with the other eye. (3) Interviews with the subjects indicated that the Landolt rings were particularly clear after viewing the stereoscopic 3-D images.

Stereoscopic Visual Attention-Based Regional Bit Allocation Optimization for Multiview Video Coding

Directory of Open Access Journals (Sweden)

Dai Qionghai

2010-01-01

Full Text Available We propose a Stereoscopic Visual Attention- (SVA- based regional bit allocation optimization for Multiview Video Coding (MVC by the exploiting visual redundancies from human perceptions. We propose a novel SVA model, where multiple perceptual stimuli including depth, motion, intensity, color, and orientation contrast are utilized, to simulate the visual attention mechanisms of human visual system with stereoscopic perception. Then, a semantic region-of-interest (ROI is extracted based on the saliency maps of SVA. Both objective and subjective evaluations of extracted ROIs indicated that the proposed SVA model based on ROI extraction scheme outperforms the schemes only using spatial or/and temporal visual attention clues. Finally, by using the extracted SVA-based ROIs, a regional bit allocation optimization scheme is presented to allocate more bits on SVA-based ROIs for high image quality and fewer bits on background regions for efficient compression purpose. Experimental results on MVC show that the proposed regional bit allocation algorithm can achieve over % bit-rate saving while maintaining the subjective image quality. Meanwhile, the image quality of ROIs is improved by  dB at the cost of insensitive image quality degradation of the background image.

Optimal display conditions for quantitative analysis of stereoscopic cerebral angiograms

International Nuclear Information System (INIS)

Charland, P.; Peters, T.; McGill Univ., Montreal, Quebec

1996-01-01

For several years the authors have been using a stereoscopic display as a tool in the planning of stereotactic neurosurgical techniques. This PC-based workstation allows the surgeon to interact with and view vascular images in three dimensions, as well as to perform quantitative analysis of the three-dimensional (3-D) space. Some of the perceptual issues relevant to the presentation of medical images on this stereoscopic display were addressed in five experiments. The authors show that a number of parameters--namely the shape, color, and depth cue, associated with a cursor--as well as the image filtering and observer position, have a role in improving the observer's perception of a 3-D image and his ability to localize points within the stereoscopically presented 3-D image. However, an analysis of the results indicates that while varying these parameters can lead to an effect on the performance of individual observers, the effects are not consistent across observers, and the mean accuracy remains relatively constant under the different experimental conditions

Stereoscopic virtual reality models for planning tumor resection in the sellar region

Directory of Open Access Journals (Sweden)

Wang Shou-sen

2012-11-01

Full Text Available Abstract Background It is difficult for neurosurgeons to perceive the complex three-dimensional anatomical relationships in the sellar region. Methods To investigate the value of using a virtual reality system for planning resection of sellar region tumors. The study included 60 patients with sellar tumors. All patients underwent computed tomography angiography, MRI-T1W1, and contrast enhanced MRI-T1W1 image sequence scanning. The CT and MRI scanning data were collected and then imported into a Dextroscope imaging workstation, a virtual reality system that allows structures to be viewed stereoscopically. During preoperative assessment, typical images for each patient were chosen and printed out for use by the surgeons as references during surgery. Results All sellar tumor models clearly displayed bone, the internal carotid artery, circle of Willis and its branches, the optic nerve and chiasm, ventricular system, tumor, brain, soft tissue and adjacent structures. Depending on the location of the tumors, we simulated the transmononasal sphenoid sinus approach, transpterional approach, and other approaches. Eleven surgeons who used virtual reality models completed a survey questionnaire. Nine of the participants said that the virtual reality images were superior to other images but that other images needed to be used in combination with the virtual reality images. Conclusions The three-dimensional virtual reality models were helpful for individualized planning of surgery in the sellar region. Virtual reality appears to be promising as a valuable tool for sellar region surgery in the future.

Monoscopic versus stereoscopic photography in screening for clinically significant macular edema.

Science.gov (United States)

Welty, Christopher J; Agarwal, Anita; Merin, Lawrence M; Chomsky, Amy

2006-01-01

The purpose of the study was to determine whether monoscopic photography could serve as an accurate tool when used to screen for clinically significant macular edema. In a masked randomized fashion, two readers evaluated monoscopic and stereoscopic retinal photographs of 100 eyes. The photographs were evaluated first individually for probable clinically significant macular edema based on the Early Treatment Diabetic Retinopathy Study criteria and then as stereoscopic pairs. Graders were evaluated for sensitivity and specificity individually and in combination. Individually, reader one had a sensitivity of 0.93 and a specificity of 0.77, and reader two had a sensitivity of 0.88 and a specificity of 0.94. In combination, the readers had a sensitivity of 0.91 and a specificity of 0.86. They correlated on 0.76 of the stereoscopic readings and 0.92 of the monoscopic readings. These results indicate that the use of monoscopic retinal photography may be an accurate screening tool for clinically significant macular edema.

Evaluating stereoscopic displays: both efficiency measures and perceived workload sensitive to manipulations in binocular disparity

Science.gov (United States)

van Beurden, Maurice H. P. H.; Ijsselsteijn, Wijnand A.; de Kort, Yvonne A. W.

2011-03-01

Stereoscopic displays are known to offer a number of key advantages in visualizing complex 3D structures or datasets. The large majority of studies that focus on evaluating stereoscopic displays for professional applications use completion time and/or the percentage of correct answers to measure potential performance advantages. However, completion time and accuracy may not fully reflect all the benefits of stereoscopic displays. In this paper, we argue that perceived workload is an additional valuable indicator reflecting the extent to which users can benefit from using stereoscopic displays. We performed an experiment in which participants were asked to perform a visual path-tracing task within a convoluted 3D wireframe structure, varying in level of complexity of the visualised structure and level of disparity of the visualisation. The results showed that an optimal performance (completion time, accuracy and workload), depend both on task difficulty and disparity level. Stereoscopic disparity revealed a faster and more accurate task performance, whereas we observed a trend that performance on difficult tasks stands to benefit more from higher levels of disparity than performance on easy tasks. Perceived workload (as measured using the NASA-TLX) showed a similar response pattern, providing evidence that perceived workload is sensitive to variations in disparity as well as task difficulty. This suggests that perceived workload could be a useful concept, in addition to standard performance indicators, in characterising and measuring human performance advantages when using stereoscopic displays.

Stereoscopic methods in TEM

International Nuclear Information System (INIS)

Thomas, L.E.

1975-07-01

Stereoscopic methods used in TEM are reviewed. The use of stereoscopy to characterize three-dimensional structures observed by TEM has become widespread since the introduction of instruments operating at 1 MV. In its emphasis on whole structures and thick specimens this approach differs significantly from conventional methods of microstructural analysis based on three-dimensional image reconstruction from a number of thin-section views. The great advantage of stereo derives from the ability to directly perceive and measure structures in three-dimensions by capitalizing on the unsurpassed human ability for stereoscopic matching of corresponding details on picture pairs showing the same features from different viewpoints. At this time, stereo methods are aimed mainly at structural understanding at the level of dislocations, precipitates, and irradiation-induced point-defect clusters in crystal and on the cellular irradiation-induced point-defect clusters in crystal and on the cellular level of biological specimens. 3-d reconstruction methods have concentrated on the molecular level where image resolution requirements dictate the use of very thin specimens. One recent application of three-dimensional coordinate measurements is a system developed for analyzing depth variations in the numbers, sizes and total volumes of voids produced near the surfaces of metal specimens during energetic ion bombardment. This system was used to correlate the void volumes at each depth along the ion range with the number of atomic displacements produced at that depth, thereby unfolding the entire swelling versus dose relationship from a single stereo view. A later version of this system incorporating computer-controlled stereo display capabilities is now being built

Stereoscopy in diagnostic radiology and procedure planning: does stereoscopic assessment of volume-rendered CT angiograms lead to more accurate characterisation of cerebral aneurysms compared with traditional monoscopic viewing?

International Nuclear Information System (INIS)

Stewart, Nikolas; Lock, Gregory; Coucher, John; Hopcraft, Anthony

2014-01-01

Stereoscopic vision is a critical part of the human visual system, conveying more information than two-dimensional, monoscopic observation alone. This study aimed to quantify the contribution of stereoscopy in assessment of radiographic data, using widely available three-dimensional (3D)-capable display monitors by assessing whether stereoscopic viewing improved the characterisation of cerebral aneurysms. Nine radiology registrars were shown 40 different volume-rendered (VR) models of cerebral computed tomography angiograms (CTAs), each in both monoscopic and stereoscopic format and then asked to record aneurysm characteristics on short multiple-choice answer sheets. The monitor used was a current model commercially available 3D television. Responses were marked against a gold standard of assessments made by a consultant radiologist, using the original CT planar images on a diagnostic radiology computer workstation. The participants' results were fairly homogenous, with most showing no difference in diagnosis using stereoscopic VR models. One participant performed better on the monoscopic VR models. On average, monoscopic VRs achieved a slightly better diagnosis by 2.0%. Stereoscopy has a long history, but it has only recently become technically feasible for stored cross-sectional data to be adequately reformatted and displayed in this format. Scant literature exists to quantify the technology's possible contribution to medical imaging - this study attempts to build on this limited knowledge base and promote discussion within the field. Stereoscopic viewing of images should be further investigated and may well eventually find a permanent place in procedural and diagnostic medical imaging.

Size Optimization of 3D Stereoscopic Film Frames

African Journals Online (AJOL)

pc

2018-03-22

Mar 22, 2018 ... perception. Keywords- Optimization; Stereoscopic Film; 3D Frames;Aspect. Ratio ... television will mature to enable the viewing of 3D films prevalent[3]. On the .... Industry Standard VFX Practices and Proced. 2014. [10] N. A. ...

SEISVIZ3D: Stereoscopic system for the representation of seismic data - Interpretation and Immersion

Science.gov (United States)

von Hartmann, Hartwig; Rilling, Stefan; Bogen, Manfred; Thomas, Rüdiger

2015-04-01

The seismic method is a valuable tool for getting 3D-images from the subsurface. Seismic data acquisition today is not only a topic for oil and gas exploration but is used also for geothermal exploration, inspections of nuclear waste sites and for scientific investigations. The system presented in this contribution may also have an impact on the visualization of 3D-data of other geophysical methods. 3D-seismic data can be displayed in different ways to give a spatial impression of the subsurface.They are a combination of individual vertical cuts, possibly linked to a cubical portion of the data volume, and the stereoscopic view of the seismic data. By these methods, the spatial perception for the structures and thus of the processes in the subsurface should be increased. Stereoscopic techniques are e. g. implemented in the CAVE and the WALL, both of which require a lot of space and high technical effort. The aim of the interpretation system shown here is stereoscopic visualization of seismic data at the workplace, i.e. at the personal workstation and monitor. The system was developed with following criteria in mind: • Fast rendering of large amounts of data so that a continuous view of the data when changing the viewing angle and the data section is possible, • defining areas in stereoscopic view to translate the spatial impression directly into an interpretation, • the development of an appropriate user interface, including head-tracking, for handling the increased degrees of freedom, • the possibility of collaboration, i.e. teamwork and idea exchange with the simultaneous viewing of a scene at remote locations. The possibilities offered by the use of a stereoscopic system do not replace a conventional interpretation workflow. Rather they have to be implemented into it as an additional step. The amplitude distribution of the seismic data is a challenge for the stereoscopic display because the opacity level and the scaling and selection of the data have to

The Effect of Two-dimensional and Stereoscopic Presentation on Middle School Students' Performance of Spatial Cognition Tasks

Science.gov (United States)

Price, Aaron; Lee, Hee-Sun

2010-02-01

We investigated whether and how student performance on three types of spatial cognition tasks differs when worked with two-dimensional or stereoscopic representations. We recruited nineteen middle school students visiting a planetarium in a large Midwestern American city and analyzed their performance on a series of spatial cognition tasks in terms of response accuracy and task completion time. Results show that response accuracy did not differ between the two types of representations while task completion time was significantly greater with the stereoscopic representations. The completion time increased as the number of mental manipulations of 3D objects increased in the tasks. Post-interviews provide evidence that some students continued to think of stereoscopic representations as two-dimensional. Based on cognitive load and cue theories, we interpret that, in the absence of pictorial depth cues, students may need more time to be familiar with stereoscopic representations for optimal performance. In light of these results, we discuss potential uses of stereoscopic representations for science learning.

The right view from the wrong location: depth perception in stereoscopic multi-user virtual environments.

Science.gov (United States)

Pollock, Brice; Burton, Melissa; Kelly, Jonathan W; Gilbert, Stephen; Winer, Eliot

2012-04-01

Stereoscopic depth cues improve depth perception and increase immersion within virtual environments (VEs). However, improper display of these cues can distort perceived distances and directions. Consider a multi-user VE, where all users view identical stereoscopic images regardless of physical location. In this scenario, cues are typically customized for one "leader" equipped with a head-tracking device. This user stands at the center of projection (CoP) and all other users ("followers") view the scene from other locations and receive improper depth cues. This paper examines perceived depth distortion when viewing stereoscopic VEs from follower perspectives and the impact of these distortions on collaborative spatial judgments. Pairs of participants made collaborative depth judgments of virtual shapes viewed from the CoP or after displacement forward or backward. Forward and backward displacement caused perceived depth compression and expansion, respectively, with greater compression than expansion. Furthermore, distortion was less than predicted by a ray-intersection model of stereo geometry. Collaboration times were significantly longer when participants stood at different locations compared to the same location, and increased with greater perceived depth discrepancy between the two viewing locations. These findings advance our understanding of spatial distortions in multi-user VEs, and suggest a strategy for reducing distortion.

Evaluating stereoscopic displays : both efficiency measures and perceived workload sensitive to manipulations in binocular disparity

NARCIS (Netherlands)

Beurden, van M.H.P.H.; IJsselsteijn, W.A.; Kort, de Y.A.W.; Woods, A.J.; Holliman, N.S.; Dodgson, N.A.

2011-01-01

Stereoscopic displays are known to offer a number of key advantages in visualizing complex 3D structures or datasets. The large majority of studies that focus on evaluating stereoscopic displays for professional applications use completion time and/or the percentage of correct answers to measure

Subjective experiences of watching stereoscopic Avatar and U2 3D in a cinema

Science.gov (United States)

Pölönen, Monika; Salmimaa, Marja; Takatalo, Jari; Häkkinen, Jukka

2012-01-01

A stereoscopic 3-D version of the film Avatar was shown to 85 people who subsequently answered questions related to sickness, visual strain, stereoscopic image quality, and sense of presence. Viewing Avatar for 165 min induced some symptoms of visual strain and sickness, but the symptom levels remained low. A comparison between Avatar and previously published results for the film U2 3D showed that sickness and visual strain levels were similar despite the films' runtimes. The genre of the film had a significant effect on the viewers' opinions and sense of presence. Avatar, which has been described as a combination of action, adventure, and sci-fi genres, was experienced as more immersive and engaging than the music documentary U2 3D. However, participants in both studies were immersed, focused, and absorbed in watching the stereoscopic 3-D (S3-D) film and were pleased with the film environments. The results also showed that previous stereoscopic 3-D experience significantly reduced the amount of reported eye strain and complaints about the weight of the viewing glasses.

YouDash3D: exploring stereoscopic 3D gaming for 3D movie theaters

Science.gov (United States)

Schild, Jonas; Seele, Sven; Masuch, Maic

2012-03-01

Along with the success of the digitally revived stereoscopic cinema, events beyond 3D movies become attractive for movie theater operators, i.e. interactive 3D games. In this paper, we present a case that explores possible challenges and solutions for interactive 3D games to be played by a movie theater audience. We analyze the setting and showcase current issues related to lighting and interaction. Our second focus is to provide gameplay mechanics that make special use of stereoscopy, especially depth-based game design. Based on these results, we present YouDash3D, a game prototype that explores public stereoscopic gameplay in a reduced kiosk setup. It features live 3D HD video stream of a professional stereo camera rig rendered in a real-time game scene. We use the effect to place the stereoscopic effigies of players into the digital game. The game showcases how stereoscopic vision can provide for a novel depth-based game mechanic. Projected trigger zones and distributed clusters of the audience video allow for easy adaptation to larger audiences and 3D movie theater gaming.

Interaksi pada Museum Virtual Menggunakan Pengindera Tangan dengan Penyajian Stereoscopic 3D

Directory of Open Access Journals (Sweden)

Gary Almas Samaita

2017-01-01

Full Text Available Kemajuan teknologi menjadikan museum mengembangkan cara penyajian koleksinya. Salah satu teknologi yang diadaptasi dalam penyajian museum virtual adalah Virtual Reality (VR dengan stereoscopic 3D. Sayangnya, museum virtual dengan teknik penyajian stereoscopic masih menggunakan keyboard dan mouse sebagai perangkat interaksi. Penelitian ini bertujuan untuk merancang dan menerapkan interaksi dengan pengindera tangan pada museum virtual dengan penyajian stereoscopic 3D. Museum virtual divisualisasikan dengan teknik stereoscopic side-by-side melalui Head Mounting Display (HMD berbasis Android. HMD juga memiliki fungsi head tracking dengan membaca orientasi kepala. Interaksi tangan diterapkan dengan menggunakan pengindera tangan yang ditempatkan pada HMD. Karena pengindera tangan tidak didukung oleh HMD berbasis Android, maka digunakan server sebagai perantara HMD dan pengindera tangan. Setelah melalui pengujian, diketahui bahwa rata-rata confidence rate dari pembacaan pengindera tangan pada pola tangan untuk memicu interaksi adalah sebesar 99,92% dengan rata-rata efektifitas 92,61%. Uji ketergunaan juga dilakukan dengan pendasaran ISO/IEC 9126-4 untuk mengukur efektifitas, efisiensi, dan kepuasan pengguna dari sistem yang dirancang dengan meminta partisipan untuk melakukan 9 tugas yang mewakili interaksi tangan dalam museum virtual. Hasil pengujian menunjukkan bahwa semua pola tangan yang dirancang dapat dilakukan oleh partisipan meskipun pola tangan dinilai cukup sulit dilakukan. Melalui kuisioner diketahui bahwa total 86,67% partisipan setuju bahwa interaksi tangan memberikan pengalaman baru dalam menikmati museum virtual.

Dynamic stereoscopic selective visual attention (dssva): integrating motion and shape with depth in video segmentation

OpenAIRE

López Bonal, María Teresa; Fernández Caballero, Antonio; Saiz Valverde, Sergio

2008-01-01

Depth inclusion as an important parameter for dynamic selective visual attention is presented in this article. The model introduced in this paper is based on two previously developed models, dynamic selective visual attention and visual stereoscopy, giving rise to the so-called dynamic stereoscopic selective visual attention method. The three models are based on the accumulative computation problem-solving method. This paper shows how software reusability enables enhancing results in vision r...

No-reference stereoscopic image quality measurement based on generalized local ternary patterns of binocular energy response

International Nuclear Information System (INIS)

Zhou, Wujie; Yu, Lu

2015-01-01

Perceptual no-reference (NR) quality measurement of stereoscopic images has become a challenging issue in three-dimensional (3D) imaging fields. In this article, we propose an efficient binocular quality-aware features extraction scheme, namely generalized local ternary patterns (GLTP) of binocular energy response, for general-purpose NR stereoscopic image quality measurement (SIQM). More specifically, we first construct the binocular energy response of a distorted stereoscopic image with different stimuli of amplitude and phase shifts. Then, the binocular quality-aware features are generated from the GLTP of the binocular energy response. Finally, these features are mapped to the subjective quality score of the distorted stereoscopic image by using support vector regression. Experiments on two publicly available 3D databases confirm the effectiveness of the proposed metric compared with the state-of-the-art full reference and NR metrics. (paper)

Designing stereoscopic information visualization for 3D-TV: What can we can learn from S3D gaming?

Science.gov (United States)

Schild, Jonas; Masuch, Maic

2012-03-01

This paper explores graphical design and spatial alignment of visual information and graphical elements into stereoscopically filmed content, e.g. captions, subtitles, and especially more complex elements in 3D-TV productions. The method used is a descriptive analysis of existing computer- and video games that have been adapted for stereoscopic display using semi-automatic rendering techniques (e.g. Nvidia 3D Vision) or games which have been specifically designed for stereoscopic vision. Digital games often feature compelling visual interfaces that combine high usability with creative visual design. We explore selected examples of game interfaces in stereoscopic vision regarding their stereoscopic characteristics, how they draw attention, how we judge effect and comfort and where the interfaces fail. As a result, we propose a list of five aspects which should be considered when designing stereoscopic visual information: explicit information, implicit information, spatial reference, drawing attention, and vertical alignment. We discuss possible consequences, opportunities and challenges for integrating visual information elements into 3D-TV content. This work shall further help to improve current editing systems and identifies a need for future editing systems for 3DTV, e.g., live editing and real-time alignment of visual information into 3D footage.

Novel microscope-integrated stereoscopic heads-up display for intrasurgical optical coherence tomography

Science.gov (United States)

Shen, Liangbo; Carrasco-Zevallos, Oscar; Keller, Brenton; Viehland, Christian; Waterman, Gar; Hahn, Paul S.; Kuo, Anthony N.; Toth, Cynthia A.; Izatt, Joseph A.

2016-01-01

Intra-operative optical coherence tomography (OCT) requires a display technology which allows surgeons to visualize OCT data without disrupting surgery. Previous research and commercial intrasurgical OCT systems have integrated heads-up display (HUD) systems into surgical microscopes to provide monoscopic viewing of OCT data through one microscope ocular. To take full advantage of our previously reported real-time volumetric microscope-integrated OCT (4D MIOCT) system, we describe a stereoscopic HUD which projects a stereo pair of OCT volume renderings into both oculars simultaneously. The stereoscopic HUD uses a novel optical design employing spatial multiplexing to project dual OCT volume renderings utilizing a single micro-display. The optical performance of the surgical microscope with the HUD was quantitatively characterized and the addition of the HUD was found not to substantially effect the resolution, field of view, or pincushion distortion of the operating microscope. In a pilot depth perception subject study, five ophthalmic surgeons completed a pre-set dexterity task with 50.0% (SD = 37.3%) higher success rate and in 35.0% (SD = 24.8%) less time on average with stereoscopic OCT vision compared to monoscopic OCT vision. Preliminary experience using the HUD in 40 vitreo-retinal human surgeries by five ophthalmic surgeons is reported, in which all surgeons reported that the HUD did not alter their normal view of surgery and that live surgical maneuvers were readily visible in displayed stereoscopic OCT volumes. PMID:27231616

Novel microscope-integrated stereoscopic heads-up display for intrasurgical optical coherence tomography.

Science.gov (United States)

Shen, Liangbo; Carrasco-Zevallos, Oscar; Keller, Brenton; Viehland, Christian; Waterman, Gar; Hahn, Paul S; Kuo, Anthony N; Toth, Cynthia A; Izatt, Joseph A

2016-05-01

Intra-operative optical coherence tomography (OCT) requires a display technology which allows surgeons to visualize OCT data without disrupting surgery. Previous research and commercial intrasurgical OCT systems have integrated heads-up display (HUD) systems into surgical microscopes to provide monoscopic viewing of OCT data through one microscope ocular. To take full advantage of our previously reported real-time volumetric microscope-integrated OCT (4D MIOCT) system, we describe a stereoscopic HUD which projects a stereo pair of OCT volume renderings into both oculars simultaneously. The stereoscopic HUD uses a novel optical design employing spatial multiplexing to project dual OCT volume renderings utilizing a single micro-display. The optical performance of the surgical microscope with the HUD was quantitatively characterized and the addition of the HUD was found not to substantially effect the resolution, field of view, or pincushion distortion of the operating microscope. In a pilot depth perception subject study, five ophthalmic surgeons completed a pre-set dexterity task with 50.0% (SD = 37.3%) higher success rate and in 35.0% (SD = 24.8%) less time on average with stereoscopic OCT vision compared to monoscopic OCT vision. Preliminary experience using the HUD in 40 vitreo-retinal human surgeries by five ophthalmic surgeons is reported, in which all surgeons reported that the HUD did not alter their normal view of surgery and that live surgical maneuvers were readily visible in displayed stereoscopic OCT volumes.

Quantitative evaluation of papilledema from stereoscopic color fundus photographs.

Science.gov (United States)

Tang, Li; Kardon, Randy H; Wang, Jui-Kai; Garvin, Mona K; Lee, Kyungmoo; Abràmoff, Michael D

2012-07-03

To derive a computerized measurement of optic disc volume from digital stereoscopic fundus photographs for the purpose of diagnosing and managing papilledema. Twenty-nine pairs of stereoscopic fundus photographs and optic nerve head (ONH) centered spectral domain optical coherence tomography (SD-OCT) scans were obtained at the same visit in 15 patients with papilledema. Some patients were imaged at multiple visits in order to assess their changes. Three-dimensional shape of the ONH was estimated from stereo fundus photographs using an automated multi-scale stereo correspondence algorithm. We assessed the correlation of the stereo volume measurements with the SD-OCT volume measurements quantitatively, in terms of volume of retinal surface elevation above a reference plane and also to expert grading of papilledema from digital fundus photographs using the Frisén grading scale. The volumetric measurements of retinal surface elevation estimated from stereo fundus photographs and OCT scans were positively correlated (correlation coefficient r(2) = 0.60; P photographs compares favorably with that from OCT scans and with expert grading of papilledema severity. Stereoscopic color imaging of the ONH combined with a method of automated shape reconstruction is a low-cost alternative to SD-OCT scans that has potential for a more cost-effective diagnosis and management of papilledema in a telemedical setting. An automated three-dimensional image analysis method was validated that quantifies the retinal surface topography with an imaging modality that has lacked prior objective assessment.

Evaluation of stereoscopic medical video content on an autostereoscopic display for undergraduate medical education

Science.gov (United States)

Ilgner, Justus F. R.; Kawai, Takashi; Shibata, Takashi; Yamazoe, Takashi; Westhofen, Martin

2006-02-01

Introduction: An increasing number of surgical procedures are performed in a microsurgical and minimally-invasive fashion. However, the performance of surgery, its possibilities and limitations become difficult to teach. Stereoscopic video has evolved from a complex production process and expensive hardware towards rapid editing of video streams with standard and HDTV resolution which can be displayed on portable equipment. This study evaluates the usefulness of stereoscopic video in teaching undergraduate medical students. Material and methods: From an earlier study we chose two clips each of three different microsurgical operations (tympanoplasty type III of the ear, endonasal operation of the paranasal sinuses and laser chordectomy for carcinoma of the larynx). This material was added by 23 clips of a cochlear implantation, which was specifically edited for a portable computer with an autostereoscopic display (PC-RD1-3D, SHARP Corp., Japan). The recording and synchronization of left and right image was performed at the University Hospital Aachen. The footage was edited stereoscopically at the Waseda University by means of our original software for non-linear editing of stereoscopic 3-D movies. Then the material was converted into the streaming 3-D video format. The purpose of the conversion was to present the video clips by a file type that does not depend on a television signal such as PAL or NTSC. 25 4th year medical students who participated in the general ENT course at Aachen University Hospital were asked to estimate depth clues within the six video clips plus cochlear implantation clips. Another 25 4th year students who were shown the material monoscopically on a conventional laptop served as control. Results: All participants noted that the additional depth information helped with understanding the relation of anatomical structures, even though none had hands-on experience with Ear, Nose and Throat operations before or during the course. The monoscopic

Phase-only stereoscopic hologram calculation based on Gerchberg–Saxton iterative algorithm

International Nuclear Information System (INIS)

Xia Xinyi; Xia Jun

2016-01-01

A phase-only computer-generated holography (CGH) calculation method for stereoscopic holography is proposed in this paper. The two-dimensional (2D) perspective projection views of the three-dimensional (3D) object are generated by the computer graphics rendering techniques. Based on these views, a phase-only hologram is calculated by using the Gerchberg–Saxton (GS) iterative algorithm. Comparing with the non-iterative algorithm in the conventional stereoscopic holography, the proposed method improves the holographic image quality, especially for the phase-only hologram encoded from the complex distribution. Both simulation and optical experiment results demonstrate that our proposed method can give higher quality reconstruction comparing with the traditional method. (special topic)

3-D flow characterization and shear stress in a stenosed carotid artery bifurcation model using stereoscopic PIV technique.

Science.gov (United States)

Kefayati, Sarah; Poepping, Tamie L

2010-01-01

The carotid artery bifurcation is a common site of atherosclerosis which is a major leading cause of ischemic stroke. The impact of stenosis in the atherosclerotic carotid artery is to disturb the flow pattern and produce regions with high shear rate, turbulence, and recirculation, which are key hemodynamic factors associated with plaque rupture, clot formation, and embolism. In order to characterize the disturbed flow in the stenosed carotid artery, stereoscopic PIV measurements were performed in a transparent model with 50% stenosis under pulsatile flow conditions. Simulated ECG gating of the flowrate waveform provides external triggering required for volumetric reconstruction of the complex flow patterns. Based on the three-component velocity data in the lumen region, volumetric shear-stress patterns were derived.

Passive method of eliminating accommodation/convergence disparity in stereoscopic head-mounted displays

Science.gov (United States)

Eichenlaub, Jesse B.

2005-03-01

The difference in accommodation and convergence distance experienced when viewing stereoscopic displays has long been recognized as a source of visual discomfort. It is especially problematic in head mounted virtual reality and enhanced reality displays, where images must often be displayed across a large depth range or superimposed on real objects. DTI has demonstrated a novel method of creating stereoscopic images in which the focus and fixation distances are closely matched for all parts of the scene from close distances to infinity. The method is passive in the sense that it does not rely on eye tracking, moving parts, variable focus optics, vibrating optics, or feedback loops. The method uses a rapidly changing illumination pattern in combination with a high speed microdisplay to create cones of light that converge at different distances to form the voxels of a high resolution space filling image. A bench model display was built and a series of visual tests were performed in order to demonstrate the concept and investigate both its capabilities and limitations. Results proved conclusively that real optical images were being formed and that observers had to change their focus to read text or see objects at different distances

A systematized WYSIWYG pipeline for digital stereoscopic 3D filmmaking

Science.gov (United States)

Mueller, Robert; Ward, Chris; Hušák, Michal

2008-02-01

Digital tools are transforming stereoscopic 3D content creation and delivery, creating an opportunity for the broad acceptance and success of stereoscopic 3D films. Beginning in late 2005, a series of mostly CGI features has successfully initiated the public to this new generation of highly-comfortable, artifact-free digital 3D. While the response has been decidedly favorable, a lack of high-quality live-action films could hinder long-term success. Liveaction stereoscopic films have historically been more time-consuming, costly, and creatively-limiting than 2D films - thus a need arises for a live-action 3D filmmaking process which minimizes such limitations. A unique 'systematized' what-you-see-is-what-you-get (WYSIWYG) pipeline is described which allows the efficient, intuitive and accurate capture and integration of 3D and 2D elements from multiple shoots and sources - both live-action and CGI. Throughout this pipeline, digital tools utilize a consistent algorithm to provide meaningful and accurate visual depth references with respect to the viewing audience in the target theater environment. This intuitive, visual approach introduces efficiency and creativity to the 3D filmmaking process by eliminating both the need for a 'mathematician mentality' of spreadsheets and calculators, as well as any trial and error guesswork, while enabling the most comfortable, 'pixel-perfect', artifact-free 3D product possible.

Teaching with Stereoscopic Video: Opportunities and Challenges

Science.gov (United States)

Variano, Evan

2017-11-01

I will present my work on creating stereoscopic videos for fluid pedagogy. I discuss a variety of workflows for content creation and a variety of platforms for content delivery. I review the qualitative lessons learned when teaching with this material, and discuss outlook for the future. This work was partially supported by the NSF award ENG-1604026 and the UC Berkeley Student Technology Fund.

Application of stereoscopic particle image velocimetry to studies of transport in a dusty (complex) plasma

International Nuclear Information System (INIS)

Thomas, Edward Jr.; Williams, Jeremiah D.; Silver, Jennifer

2004-01-01

Over the past 5 years, two-dimensional particle image velocimetry (PIV) techniques [E. Thomas, Jr., Phys. Plasmas 6, 2672 (1999)] have been used to obtain detailed measurements of microparticle transport in dusty plasmas. This Letter reports on an extension of these techniques to a three-dimensional velocity vector measurement approach using stereoscopic PIV. Initial measurements using the stereoscopic PIV diagnostic are presented

Evaluating visual discomfort in stereoscopic projection-based CAVE system with a close viewing distance

Science.gov (United States)

Song, Weitao; Weng, Dongdong; Feng, Dan; Li, Yuqian; Liu, Yue; Wang, Yongtian

2015-05-01

As one of popular immersive Virtual Reality (VR) systems, stereoscopic cave automatic virtual environment (CAVE) system is typically consisted of 4 to 6 3m-by-3m sides of a room made of rear-projected screens. While many endeavors have been made to reduce the size of the projection-based CAVE system, the issue of asthenopia caused by lengthy exposure to stereoscopic images in such CAVE with a close viewing distance was seldom tangled. In this paper, we propose a light-weighted approach which utilizes a convex eyepiece to reduce visual discomfort induced by stereoscopic vision. An empirical experiment was conducted to examine the feasibility of convex eyepiece in a large depth of field (DOF) at close viewing distance both objectively and subjectively. The result shows the positive effects of convex eyepiece on the relief of eyestrain.

Architecture for high performance stereoscopic game rendering on Android

Science.gov (United States)

Flack, Julien; Sanderson, Hugh; Shetty, Sampath

2014-03-01

Stereoscopic gaming is a popular source of content for consumer 3D display systems. There has been a significant shift in the gaming industry towards casual games for mobile devices running on the Android™ Operating System and driven by ARM™ and other low power processors. Such systems are now being integrated directly into the next generation of 3D TVs potentially removing the requirement for an external games console. Although native stereo support has been integrated into some high profile titles on established platforms like Windows PC and PS3 there is a lack of GPU independent 3D support for the emerging Android platform. We describe a framework for enabling stereoscopic 3D gaming on Android for applications on mobile devices, set top boxes and TVs. A core component of the architecture is a 3D game driver, which is integrated into the Android OpenGL™ ES graphics stack to convert existing 2D graphics applications into stereoscopic 3D in real-time. The architecture includes a method of analyzing 2D games and using rule based Artificial Intelligence (AI) to position separate objects in 3D space. We describe an innovative stereo 3D rendering technique to separate the views in the depth domain and render directly into the display buffer. The advantages of the stereo renderer are demonstrated by characterizing the performance in comparison to more traditional render techniques, including depth based image rendering, both in terms of frame rates and impact on battery consumption.

Improving maps of ice-sheet surface elevation change using combined laser altimeter and stereoscopic elevation model data

DEFF Research Database (Denmark)

Fredenslund Levinsen, Joanna; Howat, I. M.; Tscherning, C. C.

2013-01-01

We combine the complementary characteristics of laser altimeter data and stereoscopic digital elevation models (DEMs) to construct high-resolution (_100 m) maps of surface elevations and elevation changes over rapidly changing outlet glaciers in Greenland. Measurements from spaceborne and airborne...... laser altimeters have relatively low errors but are spatially limited to the ground tracks, while DEMs have larger errors but provide spatially continuous surfaces. The principle of our method is to fit the DEM surface to the altimeter point clouds in time and space to minimize the DEM errors and use...... that surface to extrapolate elevations away from altimeter flight lines. This reduces the DEM registration errors and fills the gap between the altimeter paths. We use data from ICESat and ATM as well as SPOT 5 DEMs from 2007 and 2008 and apply them to the outlet glaciers Jakobshavn Isbræ (JI...

Application of longitudinal magnification effect to magnification stereoscopic angiography. A new method of cerebral angiography

Energy Technology Data Exchange (ETDEWEB)

Doi, K.; Rossmann, K.; Duda, E.E.

1976-01-01

A new method of stereoscopic cerebral angiography was developed which employs 2X radiographic magnification. In order to obtain the same depth perception in the object as with conventional contact stereoscopic angiography, one can make the x-ray exposures at two focal spot positions which are separated by only 1 inch, whereas the contact technique requires a separation of 4 inches. The smaller distance is possible because, with 2X magnification, the transverse detail in the object is magnified by a factor of two, but the longitudinal detail, which is related to the stereo effect, is magnified by a factor of four, due to the longitudinal magnification effect. The small focal spot separation results in advantages such as improved stereoscopic image detail, better image quality, and low radiation exposure to the patient.

Application of longitudinal magnification effect to magnification stereoscopic angiography. A new method of cerebral angiography

International Nuclear Information System (INIS)

Doi, K.; Rossmann, K.; Duda, E.E.

1976-01-01

A new method of stereoscopic cerebral angiography was developed which employs 2X radiographic magnification. In order to obtain the same depth perception in the object as with conventional contact stereoscopic angiography, one can make the x-ray exposures at two focal spot positions which are separated by only 1 inch, whereas the contact technique requires a separation of 4 inches. The smaller distance is possible because, with 2X magnification, the transverse detail in the object is magnified by a factor of two, but the longitudinal detail, which is related to the stereo effect, is magnified by a factor of four, due to the longitudinal magnification effect. The small focal spot separation results in advantages such as improved stereoscopic image detail, better image quality, and low radiation exposure to the patient

Diffuse nitrogen loss simulation and impact assessment of stereoscopic agriculture pattern by integrated water system model and consideration of multiple existence forms

Science.gov (United States)

Zhang, Yongyong; Gao, Yang; Yu, Qiang

2017-09-01

Agricultural nitrogen loss becomes an increasingly important source of water quality deterioration and eutrophication, even threatens water safety for humanity. Nitrogen dynamic mechanism is still too complicated to be well captured at watershed scale due to its multiple existence forms and instability, disturbance of agricultural management practices. Stereoscopic agriculture is a novel agricultural planting pattern to efficiently use local natural resources (e.g., water, land, sunshine, heat and fertilizer). It is widely promoted as a high yield system and can obtain considerable economic benefits, particularly in China. However, its environmental quality implication is not clear. In our study, Qianyanzhou station is famous for its stereoscopic agriculture pattern of Southern China, and an experimental watershed was selected as our study area. Regional characteristics of runoff and nitrogen losses were simulated by an integrated water system model (HEQM) with multi-objective calibration, and multiple agriculture practices were assessed to find the effective approach for the reduction of diffuse nitrogen losses. Results showed that daily variations of runoff and nitrogen forms were well reproduced throughout watershed, i.e., satisfactory performances for ammonium and nitrate nitrogen (NH4-N and NO3-N) loads, good performances for runoff and organic nitrogen (ON) load, and very good performance for total nitrogen (TN) load. The average loss coefficient was 62.74 kg/ha for NH4-N, 0.98 kg/ha for NO3-N, 0.0004 kg/ha for ON and 63.80 kg/ha for TN. The dominating form of nitrogen losses was NH4-N due to the applied fertilizers, and the most dramatic zones aggregated in the middle and downstream regions covered by paddy and orange orchard. In order to control diffuse nitrogen losses, the most effective practices for Qianyanzhou stereoscopic agriculture pattern were to reduce farmland planting scale in the valley by afforestation, particularly for orchard in the

Taking space literally: reconceptualizing the effects of stereoscopic representation on user experience

Directory of Open Access Journals (Sweden)

Benny Liebold

2013-03-01

Full Text Available Recently, cinemas, home theater systems and game consoles have undergone a rapid evolution towards stereoscopic representation with recipients gradually becoming accustomed to these changes. Stereoscopy techniques in most media present two offset images separately to the left and right eye of the viewer (usually with the help of glasses separating both images resulting in the perception of three-dimensional depth. In contrast to these mass market techniques, true 3D volumetric displays or holograms that display an image in three full dimensions are relatively uncommon. The visual quality and visual comfort of stereoscopic representation is constantly being improved by the industry.

Lie group model neuromorphic geometric engine for real-time terrain reconstruction from stereoscopic aerial photos

Science.gov (United States)

Tsao, Thomas R.; Tsao, Doris

1997-04-01

In the 1980's, neurobiologist suggested a simple mechanism in primate visual cortex for maintaining a stable and invariant representation of a moving object. The receptive field of visual neurons has real-time transforms in response to motion, to maintain a stable representation. When the visual stimulus is changed due to motion, the geometric transform of the stimulus triggers a dual transform of the receptive field. This dual transform in the receptive fields compensates geometric variation in the stimulus. This process can be modelled using a Lie group method. The massive array of affine parameter sensing circuits will function as a smart sensor tightly coupled to the passive imaging sensor (retina). Neural geometric engine is a neuromorphic computing device simulating our Lie group model of spatial perception of primate's primal visual cortex. We have developed the computer simulation and experimented on realistic and synthetic image data, and performed a preliminary research of using analog VLSI technology for implementation of the neural geometric engine. We have benchmark tested on DMA's terrain data with their result and have built an analog integrated circuit to verify the computational structure of the engine. When fully implemented on ANALOG VLSI chip, we will be able to accurately reconstruct a 3D terrain surface in real-time from stereoscopic imagery.

A 3-D mixed-reality system for stereoscopic visualization of medical dataset.

Science.gov (United States)

Ferrari, Vincenzo; Megali, Giuseppe; Troia, Elena; Pietrabissa, Andrea; Mosca, Franco

2009-11-01

We developed a simple, light, and cheap 3-D visualization device based on mixed reality that can be used by physicians to see preoperative radiological exams in a natural way. The system allows the user to see stereoscopic "augmented images," which are created by mixing 3-D virtual models of anatomies obtained by processing preoperative volumetric radiological images (computed tomography or MRI) with real patient live images, grabbed by means of cameras. The interface of the system consists of a head-mounted display equipped with two high-definition cameras. Cameras are mounted in correspondence of the user's eyes and allow one to grab live images of the patient with the same point of view of the user. The system does not use any external tracker to detect movements of the user or the patient. The movements of the user's head and the alignment of virtual patient with the real one are done using machine vision methods applied on pairs of live images. Experimental results, concerning frame rate and alignment precision between virtual and real patient, demonstrate that machine vision methods used for localization are appropriate for the specific application and that systems based on stereoscopic mixed reality are feasible and can be proficiently adopted in clinical practice.

Stereoscopic optical viewing system

Science.gov (United States)

Tallman, C.S.

1986-05-02

An improved optical system which provides the operator with a stereoscopic viewing field and depth of vision, particularly suitable for use in various machines such as electron or laser beam welding and drilling machines. The system features two separate but independently controlled optical viewing assemblies from the eyepiece to a spot directly above the working surface. Each optical assembly comprises a combination of eye pieces, turning prisms, telephoto lenses for providing magnification, achromatic imaging relay lenses and final stage pentagonal turning prisms. Adjustment for variations in distance from the turning prisms to the workpiece, necessitated by varying part sizes and configurations and by the operator's visual accuity, is provided separately for each optical assembly by means of separate manual controls at the operator console or within easy reach of the operator.

Influence of stereoscopic vision on task performance with an operating microscope

NARCIS (Netherlands)

Nibourg, Lisanne M.; Wanders, Wouter; Cornelissen, Frans W.; Koopmans, Steven A.

PURPOSE: To determine the extent to which stereoscopic depth perception influences the performance of tasks executed under an operating microscope. SETTING: Laboratory of Experimental Ophthalmology, University Medical Center Groningen, the Netherlands. DESIGN: Experimental study. METHODS: Medical

Continuous monitoring of prostate position using stereoscopic and monoscopic kV image guidance

Energy Technology Data Exchange (ETDEWEB)

Stevens, M. Tynan R.; Parsons, Dave D.; Robar, James L. [Department of Medical Physics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada and Nova Scotia Cancer Centre, QEII Health Science Centre, Halifax, Nova Scotia B3H 2Y9 (Canada)

2016-05-15

Purpose: To demonstrate continuous kV x-ray monitoring of prostate motion using both stereoscopic and monoscopic localizations, assess the spatial accuracy of these techniques, and evaluate the dose delivered from the added image guidance. Methods: The authors implemented both stereoscopic and monoscopic fiducial localizations using a room-mounted dual oblique x-ray system. Recently developed monoscopic 3D position estimation techniques potentially overcome the issue of treatment head interference with stereoscopic imaging at certain gantry angles. To demonstrate continuous position monitoring, a gold fiducial marker was placed in an anthropomorphic phantom and placed on the Linac couch. The couch was used as a programmable translation stage. The couch was programmed with a series of patient prostate motion trajectories exemplifying five distinct categories: stable prostate, slow drift, persistent excursion, transient excursion, and high frequency excursions. The phantom and fiducial were imaged using 140 kVp, 0.63 mAs per image at 1 Hz for a 60 s monitoring period. Both stereoscopic and monoscopic 3D localization accuracies were assessed by comparison to the ground-truth obtained from the Linac log file. Imaging dose was also assessed, using optically stimulated luminescence dosimeter inserts in the phantom. Results: Stereoscopic localization accuracy varied between 0.13 ± 0.05 and 0.33 ± 0.30 mm, depending on the motion trajectory. Monoscopic localization accuracy varied from 0.2 ± 0.1 to 1.1 ± 0.7 mm. The largest localization errors were typically observed in the left–right direction. There were significant differences in accuracy between the two monoscopic views, but which view was better varied from trajectory to trajectory. The imaging dose was measured to be between 2 and 15 μGy/mAs, depending on location in the phantom. Conclusions: The authors have demonstrated the first use of monoscopic localization for a room-mounted dual x-ray system. Three

Employing WebGL to develop interactive stereoscopic 3D content for use in biomedical visualization

Science.gov (United States)

Johnston, Semay; Renambot, Luc; Sauter, Daniel

2013-03-01

Web Graphics Library (WebGL), the forthcoming web standard for rendering native 3D graphics in a browser, represents an important addition to the biomedical visualization toolset. It is projected to become a mainstream method of delivering 3D online content due to shrinking support for third-party plug-ins. Additionally, it provides a virtual reality (VR) experience to web users accommodated by the growing availability of stereoscopic displays (3D TV, desktop, and mobile). WebGL's value in biomedical visualization has been demonstrated by applications for interactive anatomical models, chemical and molecular visualization, and web-based volume rendering. However, a lack of instructional literature specific to the field prevents many from utilizing this technology. This project defines a WebGL design methodology for a target audience of biomedical artists with a basic understanding of web languages and 3D graphics. The methodology was informed by the development of an interactive web application depicting the anatomy and various pathologies of the human eye. The application supports several modes of stereoscopic displays for a better understanding of 3D anatomical structures.

Stereoscopic neuroanatomy lectures using a three-dimensional virtual reality environment.

Science.gov (United States)

Kockro, Ralf A; Amaxopoulou, Christina; Killeen, Tim; Wagner, Wolfgang; Reisch, Robert; Schwandt, Eike; Gutenberg, Angelika; Giese, Alf; Stofft, Eckart; Stadie, Axel T

2015-09-01

Three-dimensional (3D) computer graphics are increasingly used to supplement the teaching of anatomy. While most systems consist of a program which produces 3D renderings on a workstation with a standard screen, the Dextrobeam virtual reality VR environment allows the presentation of spatial neuroanatomical models to larger groups of students through a stereoscopic projection system. Second-year medical students (n=169) were randomly allocated to receive a standardised pre-recorded audio lecture detailing the anatomy of the third ventricle accompanied by either a two-dimensional (2D) PowerPoint presentation (n=80) or a 3D animated tour of the third ventricle with the DextroBeam. Students completed a 10-question multiple-choice exam based on the content learned and a subjective evaluation of the teaching method immediately after the lecture. Students in the 2D group achieved a mean score of 5.19 (±2.12) compared to 5.45 (±2.16) in the 3D group, with the results in the 3D group statistically non-inferior to those of the 2D group (p<0.0001). The students rated the 3D method superior to 2D teaching in four domains (spatial understanding, application in future anatomy classes, effectiveness, enjoyableness) (p<0.01). Stereoscopically enhanced 3D lectures are valid methods of imparting neuroanatomical knowledge and are well received by students. More research is required to define and develop the role of large-group VR systems in modern neuroanatomy curricula. Copyright © 2015 Elsevier GmbH. All rights reserved.

Application of a stereoscopic digital subtraction angiography approach to blood flow analysis

International Nuclear Information System (INIS)

Fencil, L.E.; Doi, K.; Hoffmann, K.R.

1986-01-01

The authors are developing a stereoscopic digital subtraction angiographic (DSA) approach for accurate measurement of the size, magnification factor, orientation, and blood flow of a selected vessel segment. We employ a Siemens Digitron 2 and a Stereolix x-ray tube with a 25-mm tube shift. Absolute vessel sizes in each stereoscopic image are determined using the magnification factor and an iterative deconvolution technique employing the LSF of the DSA system. From data on vessel diameter and three-dimensional orientation, the effective attenuation coefficient of the diluted contrast medium can be determined, thus allowing accurate blood flow analysis in high-frame-rate DSA images. The accuracy and precision of the approach will be studied using both static and dynamic phantoms

Tissue feature-based intra-fractional motion tracking for stereoscopic x-ray image guided radiotherapy

Science.gov (United States)

Xie, Yaoqin; Xing, Lei; Gu, Jia; Liu, Wu

2013-06-01

Real-time knowledge of tumor position during radiation therapy is essential to overcome the adverse effect of intra-fractional organ motion. The goal of this work is to develop a tumor tracking strategy by effectively utilizing the inherent image features of stereoscopic x-ray images acquired during dose delivery. In stereoscopic x-ray image guided radiation delivery, two orthogonal x-ray images are acquired either simultaneously or sequentially. The essence of markerless tumor tracking is the reliable identification of inherent points with distinct tissue features on each projection image and their association between two images. The identification of the feature points on a planar x-ray image is realized by searching for points with high intensity gradient. The feature points are associated by using the scale invariance features transform descriptor. The performance of the proposed technique is evaluated by using images of a motion phantom and four archived clinical cases acquired using either a CyberKnife equipped with a stereoscopic x-ray imaging system, or a LINAC equipped with an onboard kV imager and an electronic portal imaging device. In the phantom study, the results obtained using the proposed method agree with the measurements to within 2 mm in all three directions. In the clinical study, the mean error is 0.48 ± 0.46 mm for four patient data with 144 sequential images. In this work, a tissue feature-based tracking method for stereoscopic x-ray image guided radiation therapy is developed. The technique avoids the invasive procedure of fiducial implantation and may greatly facilitate the clinical workflow.

Tissue feature-based intra-fractional motion tracking for stereoscopic x-ray image guided radiotherapy

International Nuclear Information System (INIS)

Xie Yaoqin; Gu Jia; Xing Lei; Liu Wu

2013-01-01

Real-time knowledge of tumor position during radiation therapy is essential to overcome the adverse effect of intra-fractional organ motion. The goal of this work is to develop a tumor tracking strategy by effectively utilizing the inherent image features of stereoscopic x-ray images acquired during dose delivery. In stereoscopic x-ray image guided radiation delivery, two orthogonal x-ray images are acquired either simultaneously or sequentially. The essence of markerless tumor tracking is the reliable identification of inherent points with distinct tissue features on each projection image and their association between two images. The identification of the feature points on a planar x-ray image is realized by searching for points with high intensity gradient. The feature points are associated by using the scale invariance features transform descriptor. The performance of the proposed technique is evaluated by using images of a motion phantom and four archived clinical cases acquired using either a CyberKnife equipped with a stereoscopic x-ray imaging system, or a LINAC equipped with an onboard kV imager and an electronic portal imaging device. In the phantom study, the results obtained using the proposed method agree with the measurements to within 2 mm in all three directions. In the clinical study, the mean error is 0.48 ± 0.46 mm for four patient data with 144 sequential images. In this work, a tissue feature-based tracking method for stereoscopic x-ray image guided radiation therapy is developed. The technique avoids the invasive procedure of fiducial implantation and may greatly facilitate the clinical workflow. (paper)

Doing Textiles Experiments in Game-Based Virtual Reality: A Design of the Stereoscopic Chemical Laboratory (SCL) for Textiles Education

Science.gov (United States)

Lau, Kung Wong; Kan, Chi Wai; Lee, Pui Yuen

2017-01-01

Purpose: The purpose of this paper is to discuss the use of stereoscopic virtual technology in textile and fashion studies in particular to the area of chemical experiment. The development of a designed virtual platform, called Stereoscopic Chemical Laboratory (SCL), is introduced. Design/methodology/approach: To implement the suggested…

Matching and correlation computations in stereoscopic depth perception.

Science.gov (United States)

Doi, Takahiro; Tanabe, Seiji; Fujita, Ichiro

2011-03-02

A fundamental task of the visual system is to infer depth by using binocular disparity. To encode binocular disparity, the visual cortex performs two distinct computations: one detects matched patterns in paired images (matching computation); the other constructs the cross-correlation between the images (correlation computation). How the two computations are used in stereoscopic perception is unclear. We dissociated their contributions in near/far discrimination by varying the magnitude of the disparity across separate sessions. For small disparity (0.03°), subjects performed at chance level to a binocularly opposite-contrast (anti-correlated) random-dot stereogram (RDS) but improved their performance with the proportion of contrast-matched (correlated) dots. For large disparity (0.48°), the direction of perceived depth reversed with an anti-correlated RDS relative to that for a correlated one. Neither reversed nor normal depth was perceived when anti-correlation was applied to half of the dots. We explain the decision process as a weighted average of the two computations, with the relative weight of the correlation computation increasing with the disparity magnitude. We conclude that matching computation dominates fine depth perception, while both computations contribute to coarser depth perception. Thus, stereoscopic depth perception recruits different computations depending on the disparity magnitude.

Stereoscopic (3D) versus monoscopic (2D) laparoscopy: comparative study of performance using advanced HD optical systems in a surgical simulator model.

Science.gov (United States)

Schoenthaler, Martin; Schnell, Daniel; Wilhelm, Konrad; Schlager, Daniel; Adams, Fabian; Hein, Simon; Wetterauer, Ulrich; Miernik, Arkadiusz

2016-04-01

To compare task performances of novices and experts using advanced high-definition 3D versus 2D optical systems in a surgical simulator model. Fifty medical students (novices in laparoscopy) were randomly assigned to perform five standardized tasks adopted from the Fundamentals of Laparoscopic Surgery (FLS) curriculum in either a 2D or 3D laparoscopy simulator system. In addition, eight experts performed the same tasks. Task performances were evaluated using a validated scoring system of the SAGES/FLS program. Participants were asked to rate 16 items in a questionnaire. Overall task performance of novices was significantly better using stereoscopic visualization. Superiority of performances in 3D reached a level of significance for tasks peg transfer and precision cutting. No significant differences were noted in performances of experts when using either 2D or 3D. Overall performances of experts compared to novices were better in both 2D and 3D. Scorings in the questionnaires showed a tendency toward lower scores in the group of novices using 3D. Stereoscopic imaging significantly improves performance of laparoscopic phantom tasks of novices. The current study confirms earlier data based on a large number of participants and a standardized task and scoring system. Participants felt more confident and comfortable when using a 3D laparoscopic system. However, the question remains open whether these findings translate into faster and safer operations in a clinical setting.

Digital stereoscopic cinema: the 21st century

Science.gov (United States)

Lipton, Lenny

2008-02-01

Over 1000 theaters in more than a dozen countries have been outfitted with digital projectors using the Texas Instruments DLP engine equipped to show field-sequential 3-D movies using the polarized method of image selection. Shuttering eyewear and advanced anaglyph products are also being deployed for image selection. Many studios are in production with stereoscopic films, and some have committed to producing their entire output of animated features in 3-D. This is a time of technology change for the motion picture industry.

Flow Mapping of a Jet in Crossflow with Stereoscopic PIV

DEFF Research Database (Denmark)

Meyer, Knud Erik; Özcan, Oktay; Westergaard, C. H.

2002-01-01

Stereoscopic Particle Image Velocimetry (PIV) has been used to make a three-dimensional flow mapping of a jet in crossflow. The Reynolds number based on the free stream velocity and the jet diameter was nominally 2400. A jet-to-crossflow velocity ratio of 3.3 was used. Details of the formation...

The effects of 5.1 sound presentations on the perception of stereoscopic imagery in video games

Science.gov (United States)

Cullen, Brian; Galperin, Daniel; Collins, Karen; Hogue, Andrew; Kapralos, Bill

2013-03-01

Stereoscopic 3D (S3D) content in games, film and other audio-visual media has been steadily increasing over the past number of years. However, there are still open, fundamental questions regarding its implementation, particularly as it relates to a multi-modal experience that involves sound and haptics. Research has shown that sound has considerable impact on our perception of 2D phenomena, but very little research has considered how sound may influence stereoscopic 3D. Here we present the results of an experiment that examined the effects of 5.1 surround sound (5.1) and stereo loudspeaker setups on depth perception in relation to S3D imagery within a video game environment. Our aim was to answer the question: "can 5.1 surround sound enhance the participant's perception of depth in the stereoscopic field when compared to traditional stereo sound presentations?" In addition, our study examined how the presence or absence of Doppler frequency shift and frequency fall-off audio effects can also influence depth judgment under these conditions. Results suggest that 5.1 surround sound presentations enhance the apparent depth of stereoscopic imagery when compared to stereo presentations. Results also suggest that the addition of audio effects such as Doppler shift and frequency fall-off filters can influence the apparent depth of S3D objects.

Visual perception and stereoscopic imaging: an artist's perspective

Science.gov (United States)

Mason, Steve

2015-03-01

This paper continues my 2014 February IS and T/SPIE Convention exploration into the relationship of stereoscopic vision and consciousness (90141F-1). It was proposed then that by using stereoscopic imaging people may consciously experience, or see, what they are viewing and thereby help make them more aware of the way their brains manage and interpret visual information. Environmental imaging was suggested as a way to accomplish this. This paper is the result of further investigation, research, and follow-up imaging. A show of images, that is a result of this research, allows viewers to experience for themselves the effects of stereoscopy on consciousness. Creating dye-infused aluminum prints while employing ChromaDepth® 3D glasses, I hope to not only raise awareness of visual processing but also explore the differences and similarities between the artist and scientist―art increases right brain spatial consciousness, not only empirical thinking, while furthering the viewer's cognizance of the process of seeing. The artist must abandon preconceptions and expectations, despite what the evidence and experience may indicate in order to see what is happening in his work and to allow it to develop in ways he/she could never anticipate. This process is then revealed to the viewer in a show of work. It is in the experiencing, not just from the thinking, where insight is achieved. Directing the viewer's awareness during the experience using stereoscopic imaging allows for further understanding of the brain's function in the visual process. A cognitive transformation occurs, the preverbal "left/right brain shift," in order for viewers to "see" the space. Using what we know from recent brain research, these images will draw from certain parts of the brain when viewed in two dimensions and different ones when viewed stereoscopically, a shift, if one is looking for it, which is quite noticeable. People who have experienced these images in the context of examining their own

Case study: the introduction of stereoscopic games on the Sony PlayStation 3

Science.gov (United States)

Bickerstaff, Ian

2012-03-01

A free stereoscopic firmware update on Sony Computer Entertainment's PlayStation® 3 console provides the potential to increase enormously the popularity of stereoscopic 3D in the home. For this to succeed though, a large selection of content has to become available that exploits 3D in the best way possible. In addition to the existing challenges found in creating 3D movies and television programmes, the stereography must compensate for the dynamic and unpredictable environments found in games. Automatically, the software must map the depth range of the scene into the display's comfort zone, while minimising depth compression. This paper presents a range of techniques developed to solve this problem and the challenge of creating twice as many images as the 2D version without excessively compromising the frame rate or image quality. At the time of writing, over 80 stereoscopic PlayStation 3 games have been released and notable titles are used as examples to illustrate how the techniques have been adapted for different game genres. Since the firmware's introduction in 2010, the industry has matured with a large number of developers now producing increasingly sophisticated 3D content. New technologies such as viewer head tracking and head-mounted displays should increase the appeal of 3D in the home still further.

Current status of stereoscopic 3D LCD TV technologies

Science.gov (United States)

Choi, Hee-Jin

2011-06-01

The year 2010 may be recorded as a first year of successful commercial 3D products. Among them, the 3D LCD TVs are expected to be the major one regarding the sales volume. In this paper, the principle of current stereoscopic 3D LCD TV techniques and the required flat panel display (FPD) technologies for the realization of them are reviewed. [Figure not available: see fulltext.

Computer-enhanced stereoscopic vision in a head-mounted operating binocular

International Nuclear Information System (INIS)

Birkfellner, Wolfgang; Figl, Michael; Matula, Christian; Hummel, Johann; Hanel, Rudolf; Imhof, Herwig; Wanschitz, Felix; Wagner, Arne; Watzinger, Franz; Bergmann, Helmar

2003-01-01

Based on the Varioscope, a commercially available head-mounted operating binocular, we have developed the Varioscope AR, a see through head-mounted display (HMD) for augmented reality visualization that seamlessly fits into the infrastructure of a surgical navigation system. We have assessed the extent to which stereoscopic visualization improves target localization in computer-aided surgery in a phantom study. In order to quantify the depth perception of a user aiming at a given target, we have designed a phantom simulating typical clinical situations in skull base surgery. Sixteen steel spheres were fixed at the base of a bony skull, and several typical craniotomies were applied. After having taken CT scans, the skull was filled with opaque jelly in order to simulate brain tissue. The positions of the spheres were registered using VISIT, a system for computer-aided surgical navigation. Then attempts were made to locate the steel spheres with a bayonet probe through the craniotomies using VISIT and the Varioscope AR as a stereoscopic display device. Localization of targets 4 mm in diameter using stereoscopic vision and additional visual cues indicating target proximity had a success rate (defined as a first-trial hit rate) of 87.5%. Using monoscopic vision and target proximity indication, the success rate was found to be 66.6%. Omission of visual hints on reaching a target yielded a success rate of 79.2% in the stereo case and 56.25% with monoscopic vision. Time requirements for localizing all 16 targets ranged from 7.5 min (stereo, with proximity cues) to 10 min (mono, without proximity cues). Navigation error is primarily governed by the accuracy of registration in the navigation system, whereas the HMD does not appear to influence localization significantly. We conclude that stereo vision is a valuable tool in augmented reality guided interventions. (note)

Some theoretical aspects of the design of stereoscopic television systems

International Nuclear Information System (INIS)

Jones, A.

1980-03-01

Several parameters which together specify the performance of a stereoscopic television system which has been demonstrated in reactors are investigated theoretically. These are: (1) the minimum resolvable depth interval in object space, (2) the region of space which can be displayed in three dimensions without causing undue eyestrain to the observer, (3) distortions which may arise in the display. The resulting equations form a basis from which operational stereocameras can be designed and a particular example is given, which also illustrates the relationships between the parameters. It is argued that the extent of the stereo region (parameter (2) above) predicted by previously published work is probably too large for closed circuit television inspection. This arises because the criterion used to determine the maximum tolerable screen parallax is too generous. An alternative, based upon the size of Panum's fusional area (a property of the observer's eye) is proposed. Preliminary experimental support for the proposal is given by measurements of the extent of the stereoscopic region using a number of observers. (author)

An MR-compatible stereoscopic in-room 3D display for MR-guided interventions.

Science.gov (United States)

Brunner, Alexander; Groebner, Jens; Umathum, Reiner; Maier, Florian; Semmler, Wolfhard; Bock, Michael

2014-08-01

A commercial three-dimensional (3D) monitor was modified for use inside the scanner room to provide stereoscopic real-time visualization during magnetic resonance (MR)-guided interventions, and tested in a catheter-tracking phantom experiment at 1.5 T. Brightness, uniformity, radio frequency (RF) emissions and MR image interferences were measured. Due to modifications, the center luminance of the 3D monitor was reduced by 14%, and the addition of a Faraday shield further reduced the remaining luminance by 31%. RF emissions could be effectively shielded; only a minor signal-to-noise ratio (SNR) decrease of 4.6% was observed during imaging. During the tracking experiment, the 3D orientation of the catheter and vessel structures in the phantom could be visualized stereoscopically.

A system and method for adjusting and presenting stereoscopic content

DEFF Research Database (Denmark)

2013-01-01

on the basis of one or more vision specific parameters (0M, ThetaMuAlphaChi, ThetaMuIotaNu, DeltaTheta) indicating abnormal vision for the user. In this way, presenting stereoscopic content is enabled that is adjusted specifically to the given person. This may e.g. be used for training purposes or for improved...

Stereoscopic PIV and POD applied to the far turbulent axisymmetric jet

DEFF Research Database (Denmark)

Wähnström, Maja; George, William K.; Meyer, Knud Erik

2006-01-01

here applies stereoscopic PIV to the far field of the same jet in which the mode-2 phenomenon was first noticed. Indeed azimuthal mode-1 is maximal if all three velocity components are considered, so the new findings are confirmed. This work also addresses a number of outstanding issues from all...

Stereoscopic Planar Laser-Induced Fluorescence Imaging at 500 kHz

Science.gov (United States)

Medford, Taylor L.; Danehy, Paul M.; Jones, Stephen B.; Jiang, N.; Webster, M.; Lempert, Walter; Miller, J.; Meyer, T.

2011-01-01

A new measurement technique for obtaining time- and spatially-resolved image sequences in hypersonic flows is developed. Nitric-oxide planar laser-induced fluorescence (NO PLIF) has previously been used to investigate transition from laminar to turbulent flow in hypersonic boundary layers using both planar and volumetric imaging capabilities. Low flow rates of NO were typically seeded into the flow, minimally perturbing the flow. The volumetric imaging was performed at a measurement rate of 10 Hz using a thick planar laser sheet that excited NO fluorescence. The fluorescence was captured by a pair of cameras having slightly different views of the flow. Subsequent stereoscopic reconstruction of these images allowed the three-dimensional flow structures to be viewed. In the current paper, this approach has been extended to 50,000 times higher repetition rates. A laser operating at 500 kHz excites the seeded NO molecules, and a camera, synchronized with the laser and fitted with a beam-splitting assembly, acquires two separate images of the flow. The resulting stereoscopic images provide three-dimensional flow visualizations at 500 kHz for the first time. The 200 ns exposure time in each frame is fast enough to freeze the flow while the 500 kHz repetition rate is fast enough to time-resolve changes in the flow being studied. This method is applied to visualize the evolving hypersonic flow structures that propagate downstream of a discrete protuberance attached to a flat plate. The technique was demonstrated in the NASA Langley Research Center s 31-Inch Mach 10 Air Tunnel facility. Different tunnel Reynolds number conditions, NO flow rates and two different cylindrical protuberance heights were investigated. The location of the onset of flow unsteadiness, an indicator of transition, was observed to move downstream during the tunnel runs, coinciding with an increase in the model temperature.

What is 3D good for? A review of human performance on stereoscopic 3D displays

Science.gov (United States)

McIntire, John P.; Havig, Paul R.; Geiselman, Eric E.

2012-06-01

This work reviews the human factors-related literature on the task performance implications of stereoscopic 3D displays, in order to point out the specific performance benefits (or lack thereof) one might reasonably expect to observe when utilizing these displays. What exactly is 3D good for? Relative to traditional 2D displays, stereoscopic displays have been shown to enhance performance on a variety of depth-related tasks. These tasks include judging absolute and relative distances, finding and identifying objects (by breaking camouflage and eliciting perceptual "pop-out"), performing spatial manipulations of objects (object positioning, orienting, and tracking), and navigating. More cognitively, stereoscopic displays can improve the spatial understanding of 3D scenes or objects, improve memory/recall of scenes or objects, and improve learning of spatial relationships and environments. However, for tasks that are relatively simple, that do not strictly require depth information for good performance, where other strong cues to depth can be utilized, or for depth tasks that lie outside the effective viewing volume of the display, the purported performance benefits of 3D may be small or altogether absent. Stereoscopic 3D displays come with a host of unique human factors problems including the simulator-sickness-type symptoms of eyestrain, headache, fatigue, disorientation, nausea, and malaise, which appear to effect large numbers of viewers (perhaps as many as 25% to 50% of the general population). Thus, 3D technology should be wielded delicately and applied carefully; and perhaps used only as is necessary to ensure good performance.

An exploration of the initial effects of stereoscopic displays on optometric parameters

NARCIS (Netherlands)

Fortuin, M.F.; Lambooij, M.T.M.; IJsselsteijn, W.A.; Heynderickx, I.E.J.; Edgar, D.F.; Evans, B.J.W.

2011-01-01

PURPOSE: To compare the effect on optometric variables of reading text presented in 2-D and 3-D on two types of stereoscopic display. METHODS: This study measured changes in binocular visual acuity, fixation disparity, aligning prism, heterophoria, horizontal fusional reserves, prism facility and

Measurement of mean rotation and strain-rate tensors by using stereoscopic PIV

DEFF Research Database (Denmark)

Özcan, Oktay; Meyer, Knud Erik; Larsen, Poul Scheel

2005-01-01

A technique is described for measuring the mean velocity gradient (rate-of-displacement) tensor by using a conventional stereoscopic particle image velocimetry (SPIV) system. Planar measurement of the mean vorticity vector, rate-of-rotation and rate-of-strain tensors and the production of turbule...

Evaluation of stereoscopic video cameras synchronized with the movement of an operator's head on the teleoperation of the actual backhoe shovel

Science.gov (United States)

Minamoto, Masahiko; Matsunaga, Katsuya

1999-05-01

Operator performance while using a remote controlled backhoe shovel is described for three different stereoscopic viewing conditions: direct view, fixed stereoscopic cameras connected to a helmet mounted display (HMD), and rotating stereo camera connected and slaved to the head orientation of a free moving stereo HMD. Results showed that the head- slaved system provided the best performance.

Distortion of depth perception in virtual environments using stereoscopic displays: quantitative assessment and corrective measures

Science.gov (United States)

Kleiber, Michael; Winkelholz, Carsten

2008-02-01

The aim of the presented research was to quantify the distortion of depth perception when using stereoscopic displays. The visualization parameters of the used virtual reality system such as perspective, haploscopic separation and width of stereoscopic separation were varied. The experiment was designed to measure distortion in depth perception according to allocentric frames of reference. The results of the experiments indicate that some of the parameters have an antithetic effect which allows to compensate the distortion of depth perception for a range of depths. In contrast to earlier research which reported underestimation of depth perception we found that depth was overestimated when using true projection parameters according to the position of the eyes of the user and display geometry.

Integrating multi-view transmission system into MPEG-21 stereoscopic and multi-view DIA (digital item adaptation)

Science.gov (United States)

Lee, Seungwon; Park, Ilkwon; Kim, Manbae; Byun, Hyeran

2006-10-01

As digital broadcasting technologies have been rapidly progressed, users' expectations for realistic and interactive broadcasting services also have been increased. As one of such services, 3D multi-view broadcasting has received much attention recently. In general, all the view sequences acquired at the server are transmitted to the client. Then, the user can select a part of views or all the views according to display capabilities. However, this kind of system requires high processing power of the server as well as the client, thus posing a difficulty in practical applications. To overcome this problem, a relatively simple method is to transmit only two view-sequences requested by the client in order to deliver a stereoscopic video. In this system, effective communication between the server and the client is one of important aspects. In this paper, we propose an efficient multi-view system that transmits two view-sequences and their depth maps according to user's request. The view selection process is integrated into MPEG-21 DIA (Digital Item Adaptation) so that our system is compatible to MPEG-21 multimedia framework. DIA is generally composed of resource adaptation and descriptor adaptation. It is one of merits that SVA (stereoscopic video adaptation) descriptors defined in DIA standard are used to deliver users' preferences and device capabilities. Furthermore, multi-view descriptions related to multi-view camera and system are newly introduced. The syntax of the descriptions and their elements is represented in XML (eXtensible Markup Language) schema. If the client requests an adapted descriptor (e.g., view numbers) to the server, then the server sends its associated view sequences. Finally, we present a method which can reduce user's visual discomfort that might occur while viewing stereoscopic video. This phenomenon happens when view changes as well as when a stereoscopic image produces excessive disparity caused by a large baseline between two cameras. To

Many-core computing for space-based stereoscopic imaging

Science.gov (United States)

McCall, Paul; Torres, Gildo; LeGrand, Keith; Adjouadi, Malek; Liu, Chen; Darling, Jacob; Pernicka, Henry

The potential benefits of using parallel computing in real-time visual-based satellite proximity operations missions are investigated. Improvements in performance and relative navigation solutions over single thread systems can be achieved through multi- and many-core computing. Stochastic relative orbit determination methods benefit from the higher measurement frequencies, allowing them to more accurately determine the associated statistical properties of the relative orbital elements. More accurate orbit determination can lead to reduced fuel consumption and extended mission capabilities and duration. Inherent to the process of stereoscopic image processing is the difficulty of loading, managing, parsing, and evaluating large amounts of data efficiently, which may result in delays or highly time consuming processes for single (or few) processor systems or platforms. In this research we utilize the Single-Chip Cloud Computer (SCC), a fully programmable 48-core experimental processor, created by Intel Labs as a platform for many-core software research, provided with a high-speed on-chip network for sharing information along with advanced power management technologies and support for message-passing. The results from utilizing the SCC platform for the stereoscopic image processing application are presented in the form of Performance, Power, Energy, and Energy-Delay-Product (EDP) metrics. Also, a comparison between the SCC results and those obtained from executing the same application on a commercial PC are presented, showing the potential benefits of utilizing the SCC in particular, and any many-core platforms in general for real-time processing of visual-based satellite proximity operations missions.

Virtual and stereoscopic anatomy: when virtual reality meets medical education.

Science.gov (United States)

de Faria, Jose Weber Vieira; Teixeira, Manoel Jacobsen; de Moura Sousa Júnior, Leonardo; Otoch, Jose Pinhata; Figueiredo, Eberval Gadelha

2016-11-01

OBJECTIVE The authors sought to construct, implement, and evaluate an interactive and stereoscopic resource for teaching neuroanatomy, accessible from personal computers. METHODS Forty fresh brains (80 hemispheres) were dissected. Images of areas of interest were captured using a manual turntable and processed and stored in a 5337-image database. Pedagogic evaluation was performed in 84 graduate medical students, divided into 3 groups: 1 (conventional method), 2 (interactive nonstereoscopic), and 3 (interactive and stereoscopic). The method was evaluated through a written theory test and a lab practicum. RESULTS Groups 2 and 3 showed the highest mean scores in pedagogic evaluations and differed significantly from Group 1 (p 0.05). Size effects, measured as differences in scores before and after lectures, indicate the effectiveness of the method. ANOVA results showed significant difference (p < 0.05) between groups, and the Tukey test showed statistical differences between Group 1 and the other 2 groups (p < 0.05). No statistical differences between Groups 2 and 3 were found in the practicum. However, there were significant differences when Groups 2 and 3 were compared with Group 1 (p < 0.05). CONCLUSIONS The authors conclude that this method promoted further improvement in knowledge for students and fostered significantly higher learning when compared with traditional teaching resources.

Atomic structure of Fe thin-films on Cu(0 0 1) studied with stereoscopic photography

International Nuclear Information System (INIS)

Hattori, Azusa N.; Fujikado, M.; Uchida, T.; Okamoto, S.; Fukumoto, K.; Guo, F.Z.; Matsui, F.; Nakatani, K.; Matsushita, T.; Hattori, K.; Daimon, H.

2004-01-01

The complex magnetic properties of Fe films epitaxially grown on Cu(0 0 1) have been discussed in relation to their atomic structure. We have studied the Fe films on Cu(0 0 1) by a new direct method for three-dimensional (3D) atomic structure analysis, so-called 'stereoscopic photography'. The forward-focusing peaks in the photoelectron angular distribution pattern excited by the circularly polarized light rotate around the light axis in either clockwise or counterclockwise direction depending on the light helicity. By using a display-type spherical mirror analyzer for this phenomenon, we can obtain stereoscopic photographs of atomic structure. The photographs revealed that the iron structure changes from bcc to fcc and almost bcc structure with increasing iron film thickness

Real-time photorealistic stereoscopic rendering of fire

Science.gov (United States)

Rose, Benjamin M.; McAllister, David F.

2007-02-01

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.

Optimizing visual comfort for stereoscopic 3D display based on color-plus-depth signals.

Science.gov (United States)

Shao, Feng; Jiang, Qiuping; Fu, Randi; Yu, Mei; Jiang, Gangyi

2016-05-30

Visual comfort is a long-facing problem in stereoscopic 3D (S3D) display. In this paper, targeting to produce S3D content based on color-plus-depth signals, a general framework for depth mapping to optimize visual comfort for S3D display is proposed. The main motivation of this work is to remap the depth range of color-plus-depth signals to a new depth range that is suitable to comfortable S3D display. Towards this end, we first remap the depth range globally based on the adjusted zero disparity plane, and then present a two-stage global and local depth optimization solution to solve the visual comfort problem. The remapped depth map is used to generate the S3D output. We demonstrate the power of our approach on perceptually uncomfortable and comfortable stereoscopic images.

Measurements of steady flow through a bileaflet mechanical heart valve using stereoscopic PIV.

Science.gov (United States)

Hutchison, Chris; Sullivan, Pierre; Ethier, C Ross

2011-03-01

Computational modeling of bileaflet mechanical heart valve (BiMHV) flow requires experimentally validated datasets and improved knowledge of BiMHV fluid mechanics. In this study, flow was studied downstream of a model BiMHV in an axisymmetric aortic sinus using stereoscopic particle image velocimetry. The inlet flow was steady and the Reynolds number based on the aortic diameter was 7600. Results showed the out-of-plane velocity was of similar magnitude as the transverse velocity. Although additional studies are needed for confirmation, analysis of the out-of-plane velocity showed the possible presence of a four-cell streamwise vortex structure in the mean velocity field. Spatial data for all six Reynolds stress components were obtained. Reynolds normal stress profiles revealed similarities between the central jet and free jets. These findings are important to BiMHV flow modeling, though clinical relevance is limited due to the idealized conditions chosen. To this end, the dataset is publicly available for CFD validation purposes.

Use of the stereoscopic virtual reality display system for the detection and characterization of intracranial aneurysms: A Icomparison with conventional computed tomography workstation and 3D rotational angiography.

Science.gov (United States)

Liu, Xiujuan; Tao, Haiquan; Xiao, Xigang; Guo, Binbin; Xu, Shangcai; Sun, Na; Li, Maotong; Xie, Li; Wu, Changjun

2018-07-01

This study aimed to compare the diagnostic performance of the stereoscopic virtual reality display system with the conventional computed tomography (CT) workstation and three-dimensional rotational angiography (3DRA) for intracranial aneurysm detection and characterization, with a focus on small aneurysms and those near the bone. First, 42 patients with suspected intracranial aneurysms underwent both 256-row CT angiography (CTA) and 3DRA. Volume rendering (VR) images were captured using the conventional CT workstation. Next, VR images were transferred to the stereoscopic virtual reality display system. Two radiologists independently assessed the results that were obtained using the conventional CT workstation and stereoscopic virtual reality display system. The 3DRA results were considered as the ultimate reference standard. Based on 3DRA images, 38 aneurysms were confirmed in 42 patients. Two cases were misdiagnosed and 1 was missed when the traditional CT workstation was used. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the conventional CT workstation were 94.7%, 85.7%, 97.3%, 75%, and99.3%, respectively, on a per-aneurysm basis. The stereoscopic virtual reality display system missed a case. The sensitivity, specificity, PPV, NPV, and accuracy of the stereoscopic virtual reality display system were 100%, 85.7%, 97.4%, 100%, and 97.8%, respectively. No difference was observed in the accuracy of the traditional CT workstation, stereoscopic virtual reality display system, and 3DRA in detecting aneurysms. The stereoscopic virtual reality display system has some advantages in detecting small aneurysms and those near the bone. The virtual reality stereoscopic vision obtained through the system was found as a useful tool in intracranial aneurysm diagnosis and pre-operative 3D imaging. Copyright © 2018 Elsevier B.V. All rights reserved.

Surface topography characterization using 3D stereoscopic reconstruction of SEM images

Science.gov (United States)

Vedantha Krishna, Amogh; Flys, Olena; Reddy, Vijeth V.; Rosén, B. G.

2018-06-01

A major drawback of the optical microscope is its limitation to resolve finer details. Many microscopes have been developed to overcome the limitations set by the diffraction of visible light. The scanning electron microscope (SEM) is one such alternative: it uses electrons for imaging, which have much smaller wavelength than photons. As a result high magnification with superior image resolution can be achieved. However, SEM generates 2D images which provide limited data for surface measurements and analysis. Often many research areas require the knowledge of 3D structures as they contribute to a comprehensive understanding of microstructure by allowing effective measurements and qualitative visualization of the samples under study. For this reason, stereo photogrammetry technique is employed to convert SEM images into 3D measurable data. This paper aims to utilize a stereoscopic reconstruction technique as a reliable method for characterization of surface topography. Reconstructed results from SEM images are compared with coherence scanning interferometer (CSI) results obtained by measuring a roughness reference standard sample. This paper presents a method to select the most robust/consistent surface texture parameters that are insensitive to the uncertainties involved in the reconstruction technique itself. Results from the two-stereoscopic reconstruction algorithms are also documented in this paper.

Optoelectronic stereoscopic device for diagnostics, treatment, and developing of binocular vision

Science.gov (United States)

Pautova, Larisa; Elkhov, Victor A.; Ovechkis, Yuri N.

2003-08-01

Operation of the device is based on alternative generation of pictures for left and right eyes on the monitor screen. Controller gives pulses on LCG so that shutter for left or right eye opens synchronously with pictures. The device provides frequency of switching more than 100 Hz, and that is why the flickering is absent. Thus, a separate demonstration of images to the left eye or to the right one in turn is obtained for patients being unaware and creates the conditions of binocular perception clsoe to natural ones without any additional separation of vision fields. LC-cell transfer characteristic coodination with time parameters of monitor screen has enabled to improve stereo image quality. Complicated problem of computer stereo images with LC-glasses is so called 'ghosts' - noise images that come to blocked eye. We reduced its influence by adapting stereo images to phosphor and LC-cells characteristics. The device is intended for diagnostics and treatment of stabismus, amblyopia and other binocular and stereoscopic vision impairments, for cultivating, training and developing of stereoscopic vision, for measurements of horizontal and vertical phoria, phusion reserves, the stereovision acuity and some else, for fixing central scotoma borders, as well as suppression scotoma in strabismus too.

Web GIS in practice VII: stereoscopic 3-D solutions for online maps and virtual globes

Science.gov (United States)

Boulos, Maged N.K.; Robinson, Larry R.

2009-01-01

Because our pupils are about 6.5 cm apart, each eye views a scene from a different angle and sends a unique image to the visual cortex, which then merges the images from both eyes into a single picture. The slight difference between the right and left images allows the brain to properly perceive the 'third dimension' or depth in a scene (stereopsis). However, when a person views a conventional 2-D (two-dimensional) image representation of a 3-D (three-dimensional) scene on a conventional computer screen, each eye receives essentially the same information. Depth in such cases can only be approximately inferred from visual clues in the image, such as perspective, as only one image is offered to both eyes. The goal of stereoscopic 3-D displays is to project a slightly different image into each eye to achieve a much truer and realistic perception of depth, of different scene planes, and of object relief. This paper presents a brief review of a number of stereoscopic 3-D hardware and software solutions for creating and displaying online maps and virtual globes (such as Google Earth) in "true 3D", with costs ranging from almost free to multi-thousand pounds sterling. A practical account is also given of the experience of the USGS BRD UMESC (United States Geological Survey's Biological Resources Division, Upper Midwest Environmental Sciences Center) in setting up a low-cost, full-colour stereoscopic 3-D system.

Preliminary evaluation of a prototype stereoscopic a-Si:H-based X-ray imaging system for full-field digital mammography

International Nuclear Information System (INIS)

Darambara, D.G.; Speller, R.D.; Horrocks, J.A.; Godber, S.; Wilson, R.; Hanby, A.

2001-01-01

In a pre-clinical study, we have been investigating the potential of a-Si:H active matrix, flat panel imagers for X-ray full-field digital mammography through the development of an advanced 3D X-ray imaging system and have measured a number of their important imaging characteristics. To enhance the information embodied into the digital images produced by the a-Si array, stereoscopic images, created by viewing the object under examination from two angles and recombining the images, were obtained. This method provided us with a full 3D X-ray image of the test object as well as left and right perspective 2D images all at the same time. Within this scope, images of fresh, small human breast tissue specimens--normal and diseased--were obtained at ±2 deg., processed and stereoscopically displayed for a pre-clinical evaluation by radiologists. It was demonstrated that the stereoscopic presentation of the images provides important additional information and has potential benefits over the more traditional 2D data

Stereoscopically Observing Manipulative Actions.

Science.gov (United States)

Ferri, S; Pauwels, K; Rizzolatti, G; Orban, G A

2016-08-01

The purpose of this study was to investigate the contribution of stereopsis to the processing of observed manipulative actions. To this end, we first combined the factors "stimulus type" (action, static control, and dynamic control), "stereopsis" (present, absent) and "viewpoint" (frontal, lateral) into a single design. Four sites in premotor, retro-insular (2) and parietal cortex operated specifically when actions were viewed stereoscopically and frontally. A second experiment clarified that the stereo-action-specific regions were driven by actions moving out of the frontoparallel plane, an effect amplified by frontal viewing in premotor cortex. Analysis of single voxels and their discriminatory power showed that the representation of action in the stereo-action-specific areas was more accurate when stereopsis was active. Further analyses showed that the 4 stereo-action-specific sites form a closed network converging onto the premotor node, which connects to parietal and occipitotemporal regions outside the network. Several of the specific sites are known to process vestibular signals, suggesting that the network combines observed actions in peripersonal space with gravitational signals. These findings have wider implications for the function of premotor cortex and the role of stereopsis in human behavior. © The Author 2016. Published by Oxford University Press.

Toward 3D-IPTV: design and implementation of a stereoscopic and multiple-perspective video streaming system

Science.gov (United States)

Petrovic, Goran; Farin, Dirk; de With, Peter H. N.

2008-02-01

3D-Video systems allow a user to perceive depth in the viewed scene and to display the scene from arbitrary viewpoints interactively and on-demand. This paper presents a prototype implementation of a 3D-video streaming system using an IP network. The architecture of our streaming system is layered, where each information layer conveys a single coded video signal or coded scene-description data. We demonstrate the benefits of a layered architecture with two examples: (a) stereoscopic video streaming, (b) monoscopic video streaming with remote multiple-perspective rendering. Our implementation experiments confirm that prototyping 3D-video streaming systems is possible with today's software and hardware. Furthermore, our current operational prototype demonstrates that highly heterogeneous clients can coexist in the system, ranging from auto-stereoscopic 3D displays to resource-constrained mobile devices.

Matching methods evaluation framework for stereoscopic breast x-ray images.

Science.gov (United States)

Rousson, Johanna; Naudin, Mathieu; Marchessoux, Cédric

2016-01-01

Three-dimensional (3-D) imaging has been intensively studied in the past few decades. Depth information is an important added value of 3-D systems over two-dimensional systems. Special focuses were devoted to the development of stereo matching methods for the generation of disparity maps (i.e., depth information within a 3-D scene). Dedicated frameworks were designed to evaluate and rank the performance of different stereo matching methods but never considering x-ray medical images. Yet, 3-D x-ray acquisition systems and 3-D medical displays have already been introduced into the diagnostic market. To access the depth information within x-ray stereoscopic images, computing accurate disparity maps is essential. We aimed at developing a framework dedicated to x-ray stereoscopic breast images used to evaluate and rank several stereo matching methods. A multiresolution pyramid optimization approach was integrated to the framework to increase the accuracy and the efficiency of the stereo matching techniques. Finally, a metric was designed to score the results of the stereo matching compared with the ground truth. Eight methods were evaluated and four of them [locally scaled sum of absolute differences (LSAD), zero mean sum of absolute differences, zero mean sum of squared differences, and locally scaled mean sum of squared differences] appeared to perform equally good with an average error score of 0.04 (0 is the perfect matching). LSAD was selected for generating the disparity maps.

Poster - 48: Clinical assessment of ExacTrac stereoscopic imaging of spine alignment for lung SBRT

International Nuclear Information System (INIS)

Sattarivand, Mike; Summers, Clare; Robar, James

2016-01-01

Purpose: To evaluate the validity of using spine as a surrogate for tumor positioning with ExacTrac stereoscopic imaging in lung stereotactic body radiation therapy (SBRT). Methods: Using the Novalis ExacTrac x-ray system, 39 lung SBRT patients (182 treatments) were aligned before treatment with 6 degrees (6D) of freedom couch (3 translations, 3 rotations) based on spine matching on stereoscopic images. The couch was shifted to treatment isocenter and pre-treatment CBCT was performed based on a soft tissue match around tumor volume. The CBCT data were used to measure residual errors following ExacTrac alignment. The thresholds for re-aligning the patients based on CBCT were 3mm shift or 3° rotation (in any 6D). In order to evaluate the effect of tumor location on residual errors, correlations between tumor distance from spine and individual residual errors were calculated. Results: Residual errors were up to 0.5±2.4mm. Using 3mm/3° thresholds, 80/182 (44%) of the treatments required re-alignment based on CBCT soft tissue matching following ExacTrac spine alignment. Most mismatches were in sup-inf, ant-post, and roll directions which had larger standard deviations. No correlation was found between tumor distance from spine and individual residual errors. Conclusion: ExacTrac stereoscopic imaging offers a quick pre-treatment patient alignment. However, bone matching based on spine is not reliable for aligning lung SBRT patients who require soft tissue image registration from CBCT. Spine can be a poor surrogate for lung SBRT patient alignment even for proximal tumor volumes.

Poster - 48: Clinical assessment of ExacTrac stereoscopic imaging of spine alignment for lung SBRT

Energy Technology Data Exchange (ETDEWEB)

Sattarivand, Mike; Summers, Clare; Robar, James [Nova Scotia Cancer Centre, Nova Scotia Cancer Centre, Nova Scotia Cancer Centre (Canada)

2016-08-15

Purpose: To evaluate the validity of using spine as a surrogate for tumor positioning with ExacTrac stereoscopic imaging in lung stereotactic body radiation therapy (SBRT). Methods: Using the Novalis ExacTrac x-ray system, 39 lung SBRT patients (182 treatments) were aligned before treatment with 6 degrees (6D) of freedom couch (3 translations, 3 rotations) based on spine matching on stereoscopic images. The couch was shifted to treatment isocenter and pre-treatment CBCT was performed based on a soft tissue match around tumor volume. The CBCT data were used to measure residual errors following ExacTrac alignment. The thresholds for re-aligning the patients based on CBCT were 3mm shift or 3° rotation (in any 6D). In order to evaluate the effect of tumor location on residual errors, correlations between tumor distance from spine and individual residual errors were calculated. Results: Residual errors were up to 0.5±2.4mm. Using 3mm/3° thresholds, 80/182 (44%) of the treatments required re-alignment based on CBCT soft tissue matching following ExacTrac spine alignment. Most mismatches were in sup-inf, ant-post, and roll directions which had larger standard deviations. No correlation was found between tumor distance from spine and individual residual errors. Conclusion: ExacTrac stereoscopic imaging offers a quick pre-treatment patient alignment. However, bone matching based on spine is not reliable for aligning lung SBRT patients who require soft tissue image registration from CBCT. Spine can be a poor surrogate for lung SBRT patient alignment even for proximal tumor volumes.

The Effect of Stereoscopic ("3D") vs. 2D Presentation on Learning through Video and Film

Science.gov (United States)

Price, Aaron; Kasal, E.

2014-01-01

Two Eyes, 3D is a NSF-funded research project into the effects of stereoscopy on learning of highly spatial concepts. We report final results on one study of the project which tested the effect of stereoscopic presentation on learning outcomes of two short films about Type 1a supernovae and the morphology of the Milky Way. 986 adults watched either film, randomly distributed between stereoscopic and 2D presentation. They took a pre-test and post-test that included multiple choice and drawing tasks related to the spatial nature of the topics in the film. Orientation of the answering device was also tracked and a spatial cognition pre-test was given to control for prior spatial ability. Data collection took place at the Adler Planetarium's Space Visualization Lab and the project is run through the AAVSO.

The Impact of Stereoscopic Imagery and Motion on Anatomical Structure Recognition and Visual Attention Performance

Science.gov (United States)

Remmele, Martin; Schmidt, Elena; Lingenfelder, Melissa; Martens, Andreas

2018-01-01

Gross anatomy is located in a three-dimensional space. Visualizing aspects of structures in gross anatomy education should aim to provide information that best resembles their original spatial proportions. Stereoscopic three-dimensional imagery might offer possibilities to implement this aim, though some research has revealed potential impairments…

Broadcast-quality-stereoscopic video in a time-critical entertainment and corporate environment

Science.gov (United States)

Gay, Jean-Philippe

1995-03-01

`reality present: Peter Gabrial and Cirque du Soleil' is a 12 minute original work directed and produced by Doug Brown, Jean-Philippe Gay & A. Coogan, which showcases creative content applications of commercial stereoscopic video equipment. For production, a complete equipment package including a Steadicam mount was used in support of the Ikegami LK-33 camera. Remote production units were fielded in the time critical, on-stage and off-stage environments of 2 major live concerts: Peter Gabriel's Secret World performance at the San Diego Sports Arena, and Cirque du Soleil's Saltimbanco performance in Chicago. Twin 60 Hz video channels were captured on Beta SP for maximum post production flexibility. Digital post production and field sequential mastering were effected in D-2 format at studio facilities in Los Angeles. The program was world premiered to a large public at the World of Music, Arts and Dance festivals in Los Angeles and San Francisco, in late 1993. It was presented to the artists in Los Angeles, Montreal and Washington D.C. Additional presentations have been made using a broad range of commercial and experimental stereoscopic video equipment, including projection systems, LCD and passive eyewear, and digital signal processors. Technical packages for live presentation have been fielded on site and off, through to the present.

A comparison of cup-to-disc ratio estimates by fundus biomicroscopy and stereoscopic optic disc photography in the Tema Eye Survey.

Science.gov (United States)

Mwanza, J C; Grover, D S; Budenz, D L; Herndon, L W; Nolan, W; Whiteside-de Vos, J; Hay-Smith, G; Bandi, J R; Bhansali, K A; Forbes, L A; Feuer, W J; Barton, K

2017-08-01

PurposeTo determine if there are systematic differences in cup-to-disc ratio (CDR) grading using fundus biomicroscopy compared to stereoscopic disc photograph reading.MethodsThe vertical cup-to-disc ratio (VCDR) and horizontal cup-to-disc ratio (HCDR) of 2200 eyes (testing set) were graded by glaucoma subspecialists through fundus biomicroscopy and by a reading center using stereoscopic disc photos. For validation, the glaucoma experts also estimated VCDR and HCDR using stereoscopic disc photos in a subset of 505 eyes that they had assessed biomicroscopically. Agreement between grading methods was assessed with Bland-Altman plots.ResultsIn both sets, photo reading tended to yield small CDRs marginally larger, but read large CDRs marginally smaller than fundus biomicroscopy. The mean differences in VCDR and HCDR were 0.006±0.18 and 0.05±0.18 (testing set), and -0.053±0.23 and -0.028±0.21 (validation set), respectively. The limits of agreement were ~0.4, which is twice as large as the cutoff of clinically significant CDR difference between methods. CDR estimates differed by 0.2 or more in 33.8-48.7% between methods.ConclusionsThe differences in CDR estimates between fundus biomicroscopy and stereoscopic optic disc photo reading showed a wide variation, and reached clinically significance threshold in a large proportion of patients, suggesting a poor agreement. Thus, glaucoma should be monitored by comparing baseline and subsequent CDR estimates using the same method rather than comparing photographs to fundus biomicroscopy.

An interactive, stereoscopic virtual environment for medical imaging visualization, simulation and training

Science.gov (United States)

Krueger, Evan; Messier, Erik; Linte, Cristian A.; Diaz, Gabriel

2017-03-01

Recent advances in medical image acquisition allow for the reconstruction of anatomies with 3D, 4D, and 5D renderings. Nevertheless, standard anatomical and medical data visualization still relies heavily on the use of traditional 2D didactic tools (i.e., textbooks and slides), which restrict the presentation of image data to a 2D slice format. While these approaches have their merits beyond being cost effective and easy to disseminate, anatomy is inherently three-dimensional. By using 2D visualizations to illustrate more complex morphologies, important interactions between structures can be missed. In practice, such as in the planning and execution of surgical interventions, professionals require intricate knowledge of anatomical complexities, which can be more clearly communicated and understood through intuitive interaction with 3D volumetric datasets, such as those extracted from high-resolution CT or MRI scans. Open source, high quality, 3D medical imaging datasets are freely available, and with the emerging popularity of 3D display technologies, affordable and consistent 3D anatomical visualizations can be created. In this study we describe the design, implementation, and evaluation of one such interactive, stereoscopic visualization paradigm for human anatomy extracted from 3D medical images. A stereoscopic display was created by projecting the scene onto the lab floor using sequential frame stereo projection and viewed through active shutter glasses. By incorporating a PhaseSpace motion tracking system, a single viewer can navigate an augmented reality environment and directly manipulate virtual objects in 3D. While this paradigm is sufficiently versatile to enable a wide variety of applications in need of 3D visualization, we designed our study to work as an interactive game, which allows users to explore the anatomy of various organs and systems. In this study we describe the design, implementation, and evaluation of an interactive and stereoscopic

3D pressure imaging of an aircraft propeller blade-tip flow by phase-locked stereoscopic PIV

NARCIS (Netherlands)

Ragni, D.; Van Oudheusden, B.W.; Scarano, F.

2011-01-01

The flow field at the tip region of a scaled DHC Beaver aircraft propeller, running at transonic speed, has been investigated by means of a multi-plane stereoscopic particle image velocimetry setup. Velocity fields, phase-locked with the blade rotational motion, are acquired across several planes

Calculation of 3D Coordinates of a Point on the Basis of a Stereoscopic System

Science.gov (United States)

Mussabayev, R. R.; Kalimoldayev, M. N.; Amirgaliyev, Ye. N.; Tairova, A. T.; Mussabayev, T. R.

2018-05-01

The solution of three-dimensional (3D) coordinate calculation task for a material point is considered. Two flat images (a stereopair) which correspond to the left and to the right viewpoints of a 3D scene are used for this purpose. The stereopair is obtained using two cameras with parallel optical axes. The analytical formulas for calculating 3D coordinates of a material point in the scene were obtained on the basis of analysis of the stereoscopic system optical and geometrical schemes. The detailed presentation of the algorithmic and hardware realization of the given method was discussed with the the practical. The practical module was recommended for the determination of the optical system unknown parameters. The series of experimental investigations were conducted for verification of theoretical results. During these experiments the minor inaccuracies were occurred by space distortions in the optical system and by it discrecity. While using the high quality stereoscopic system, the existing calculation inaccuracy enables to apply the given method for the wide range of practical tasks.

Figure and ground in the visual cortex: v2 combines stereoscopic cues with gestalt rules.

Science.gov (United States)

Qiu, Fangtu T; von der Heydt, Rüdiger

2005-07-07

Figure-ground organization is a process by which the visual system identifies some image regions as foreground and others as background, inferring 3D layout from 2D displays. A recent study reported that edge responses of neurons in area V2 are selective for side-of-figure, suggesting that figure-ground organization is encoded in the contour signals (border ownership coding). Here, we show that area V2 combines two strategies of computation, one that exploits binocular stereoscopic information for the definition of local depth order, and another that exploits the global configuration of contours (Gestalt factors). These are combined in single neurons so that the "near" side of the preferred 3D edge generally coincides with the preferred side-of-figure in 2D displays. Thus, area V2 represents the borders of 2D figures as edges of surfaces, as if the figures were objects in 3D space. Even in 3D displays, Gestalt factors influence the responses and can enhance or null the stereoscopic depth information.

Stereoscopic Feature Tracking System for Retrieving Velocity of Surface Waters

Science.gov (United States)

Zuniga Zamalloa, C. C.; Landry, B. J.

2017-12-01

The present work is concerned with the surface velocity retrieval of flows using a stereoscopic setup and finding the correspondence in the images via feature tracking (FT). The feature tracking provides a key benefit of substantially reducing the level of user input. In contrast to other commonly used methods (e.g., normalized cross-correlation), FT does not require the user to prescribe interrogation window sizes and removes the need for masking when specularities are present. The results of the current FT methodology are comparable to those obtained via Large Scale Particle Image Velocimetry while requiring little to no user input which allowed for rapid, automated processing of imagery.

Study of high-definition and stereoscopic head-aimed vision for improved teleoperation of an unmanned ground vehicle

Science.gov (United States)

Tyczka, Dale R.; Wright, Robert; Janiszewski, Brian; Chatten, Martha Jane; Bowen, Thomas A.; Skibba, Brian

2012-06-01

Nearly all explosive ordnance disposal robots in use today employ monoscopic standard-definition video cameras to relay live imagery from the robot to the operator. With this approach, operators must rely on shadows and other monoscopic depth cues in order to judge distances and object depths. Alternatively, they can contact an object with the robot's manipulator to determine its position, but that approach carries with it the risk of detonation from unintentionally disturbing the target or nearby objects. We recently completed a study in which high-definition (HD) and stereoscopic video cameras were used in addition to conventional standard-definition (SD) cameras in order to determine if higher resolutions and/or stereoscopic depth cues improve operators' overall performance of various unmanned ground vehicle (UGV) tasks. We also studied the effect that the different vision modes had on operator comfort. A total of six different head-aimed vision modes were used including normal-separation HD stereo, SD stereo, "micro" (reduced separation) SD stereo, HD mono, and SD mono (two types). In general, the study results support the expectation that higher resolution and stereoscopic vision aid UGV teleoperation, but the degree of improvement was found to depend on the specific task being performed; certain tasks derived notably more benefit from improved depth perception than others. This effort was sponsored by the Joint Ground Robotics Enterprise under Robotics Technology Consortium Agreement #69-200902 T01. Technical management was provided by the U.S. Air Force Research Laboratory's Robotics Research and Development Group at Tyndall AFB, Florida.

Measurement of rotation and strain-rate tensors by using stereoscopic PIV

DEFF Research Database (Denmark)

Özcan, O.; Meyer, Knud Erik; Larsen, Poul Scheel

2004-01-01

A simple technique is described for measuring the mean rate-of-displacement (velocity gradient) tensor in a plane by using a conventional stereoscopic PIV system. The technique involves taking PIV data in two or three closely-spaced parallel planes at different times. All components of the mean...... are presented to show the applicability of the proposed technique. The PIV cameras and light sheet optics shown in Fig. 1a are mounted on the same traverse mechanism in order to displace the measurement plane accurately. Data obtained in constant-y and -z planes are presented. Fig. 1b shows a contour plot...

Organizational Learning Goes Virtual?: A Study of Employees' Learning Achievement in Stereoscopic 3D Virtual Reality

Science.gov (United States)

Lau, Kung Wong

2015-01-01

Purpose: This study aims to deepen understanding of the use of stereoscopic 3D technology (stereo3D) in facilitating organizational learning. The emergence of advanced virtual technologies, in particular to the stereo3D virtual reality, has fundamentally changed the ways in which organizations train their employees. However, in academic or…

Comparing Short- and Long-Term Learning Effects between Stereoscopic and Two-Dimensional Film at a Planetarium

Science.gov (United States)

Price, C. Aaron; Lee, Hee-Sun; Subbarao, Mark; Kasal, Evan; Aguileara, Julieta

2015-01-01

Science centers such as museums and planetariums have used stereoscopic ("three-dimensional") films to draw interest from and educate their visitors for decades. Despite the fact that most adults who are finished with their formal education get their science knowledge from such free-choice learning settings very little is known about the…

Stereoscopic Three-Dimensional Neuroanatomy Lectures Enhance Neurosurgical Training: Prospective Comparison with Traditional Teaching.

Science.gov (United States)

Clark, Anna D; Guilfoyle, Mathew R; Candy, Nicholas G; Budohoski, Karol P; Hofmann, Riikka; Barone, Damiano G; Santarius, Thomas; Kirollos, Ramez W; Trivedi, Rikin A

2017-12-01

Stereoscopic three-dimensional (3D) imaging is increasingly used in the teaching of neuroanatomy and although this is mainly aimed at undergraduate medical students, it has enormous potential for enhancing the training of neurosurgeons. This study aims to assess whether 3D lecturing is an effective method of enhancing the knowledge and confidence of neurosurgeons and how it compares with traditional two-dimensional (2D) lecturing and cadaveric training. Three separate teaching sessions for neurosurgical trainees were organized: 1) 2D course (2D lecture + cadaveric session), 2) 3D lecture alone, and 3) 3D course (3D lecture + cadaveric session). Before and after each session, delegates were asked to complete questionnaires containing questions relating to surgical experience, anatomic knowledge, confidence in performing procedures, and perceived value of 3D, 2D, and cadaveric teaching. Although both 2D and 3D lectures and courses were similarly effective at improving self-rated knowledge and understanding, the 3D lecture and course were associated with significantly greater gains in confidence reported by the delegates for performing a subfrontal approach and sylvian fissure dissection. Stereoscopic 3D lectures provide neurosurgical trainees with greater confidence for performing standard operative approaches and enhances the benefit of subsequent practical experience in developing technical skills in cadaveric dissection. Copyright © 2017. Published by Elsevier Inc.

Disparity modifications and the emotional effects of stereoscopic images

Science.gov (United States)

Kawai, Takashi; Atsuta, Daiki; Tomiyama, Yuya; Kim, Sanghyun; Morikawa, Hiroyuki; Mitsuya, Reiko; Häkkinen, Jukka

2014-03-01

This paper describes a study that focuses on disparity changes in emotional scenes of stereoscopic (3D) images, in which an examination of the effects on pleasant and arousal was carried out by adding binocular disparity to 2D images that evoke specific emotions, and applying disparity modification based on the disparity analysis of famous 3D movies. From the results of the experiment, for pleasant, a significant difference was found only for the main effect of the emotions. On the other hand, for arousal, there was a trend of increasing the evaluation values in the order 2D condition, 3D condition and 3D condition applied the disparity modification for happiness, surprise, and fear. This suggests the possibility that binocular disparity and the modification affect arousal.

The Influence of Manifest Strabismus and Stereoscopic Vision on Non-Verbal Abilities of Visually Impaired Children

Science.gov (United States)

Gligorovic, Milica; Vucinic, Vesna; Eskirovic, Branka; Jablan, Branka

2011-01-01

This research was conducted in order to examine the influence of manifest strabismus and stereoscopic vision on non-verbal abilities of visually impaired children aged between 7 and 15. The sample included 55 visually impaired children from the 1st to the 6th grade of elementary schools for visually impaired children in Belgrade. RANDOT stereotest…

Objective quality assessment of stereoscopic images with vertical disparity using EEG

Science.gov (United States)

Shahbazi Avarvand, Forooz; Bosse, Sebastian; Müller, Klaus-Robert; Schäfer, Ralf; Nolte, Guido; Wiegand, Thomas; Curio, Gabriel; Samek, Wojciech

2017-08-01

Objective. Neurophysiological correlates of vertical disparity in 3D images are studied in an objective approach using EEG technique. These disparities are known to negatively affect the quality of experience and to cause visual discomfort in stereoscopic visualizations. Approach. We have presented four conditions to subjects: one in 2D and three conditions in 3D, one without vertical disparity and two with different vertical disparity levels. Event related potentials (ERPs) are measured for each condition and the differences between ERP components are studied. Analysis is also performed on the induced potentials in the time frequency domain. Main results. Results show that there is a significant increase in the amplitude of P1 components in 3D conditions in comparison to 2D. These results are consistent with previous studies which have shown that P1 amplitude increases due to the depth perception in 3D compared to 2D. However the amplitude is significantly smaller for maximum vertical disparity (3D-3) in comparison to 3D with no vertical disparity. Our results therefore suggest that the vertical disparity in 3D-3 condition decreases the perception of depth compared to other 3D conditions and the amplitude of P1 component can be used as a discriminative feature. Significance. The results show that the P1 component increases in amplitude due to the depth perception in the 3D stimuli compared to the 2D stimulus. On the other hand the vertical disparity in the stereoscopic images is studied here. We suggest that the amplitude of P1 component is modulated with this parameter and decreases due to the decrease in the perception of depth.

Head-coupled remote stereoscopic camera system for telepresence applications

Science.gov (United States)

Bolas, Mark T.; Fisher, Scott S.

1990-09-01

The Virtual Environment Workstation Project (VIEW) at NASA's Ames Research Center has developed a remotely controlled stereoscopic camera system that can be used for telepresence research and as a tool to develop and evaluate configurations for head-coupled visual systems associated with space station telerobots and remote manipulation robotic arms. The prototype camera system consists of two lightweight CCD video cameras mounted on a computer controlled platform that provides real-time pan, tilt, and roll control of the camera system in coordination with head position transmitted from the user. This paper provides an overall system description focused on the design and implementation of the camera and platform hardware configuration and the development of control software. Results of preliminary performance evaluations are reported with emphasis on engineering and mechanical design issues and discussion of related psychophysiological effects and objectives.

Assessment of stereoscopic optic disc images using an autostereoscopic screen – experimental study

Directory of Open Access Journals (Sweden)

Vaideanu Daniella

2008-07-01

Full Text Available Abstract Background Stereoscopic assessment of the optic disc morphology is an important part of the care of patients with glaucoma. The aim of this study was to assess stereoviewing of stereoscopic optic disc images using an example of the new technology of autostereoscopic screens compared to the liquid shutter goggles. Methods Independent assessment of glaucomatous disc characteristics and measurement of optic disc and cup parameters whilst using either an autostereoscopic screen or liquid crystal shutter goggles synchronized with a view switching display. The main outcome measures were inter-modality agreements between the two used modalities as evaluated by the weighted kappa test and Bland Altman plots. Results Inter-modality agreement for measuring optic disc parameters was good [Average kappa coefficient for vertical Cup/Disc ratio was 0.78 (95% CI 0.62–0.91 and 0.81 (95% CI 0.6–0.92 for observer 1 and 2 respectively]. Agreement between modalities for assessing optic disc characteristics for glaucoma on a five-point scale was very good with a kappa value of 0.97. Conclusion This study compared two different methods of stereo viewing. The results of assessment of the different optic disc and cup parameters were comparable using an example of the newly developing autostereoscopic display technologies as compared to the shutter goggles system used. The Inter-modality agreement was high. This new technology carries potential clinical usability benefits in different areas of ophthalmic practice.

Subjective evaluation of two stereoscopic imaging systems exploiting visual attention to improve 3D quality of experience

Science.gov (United States)

Hanhart, Philippe; Ebrahimi, Touradj

2014-03-01

Crosstalk and vergence-accommodation rivalry negatively impact the quality of experience (QoE) provided by stereoscopic displays. However, exploiting visual attention and adapting the 3D rendering process on the fly can reduce these drawbacks. In this paper, we propose and evaluate two different approaches that exploit visual attention to improve 3D QoE on stereoscopic displays: an offline system, which uses a saliency map to predict gaze position, and an online system, which uses a remote eye tracking system to measure real time gaze positions. The gaze points were used in conjunction with the disparity map to extract the disparity of the object-of-interest. Horizontal image translation was performed to bring the fixated object on the screen plane. The user preference between standard 3D mode and the two proposed systems was evaluated through a subjective evaluation. Results show that exploiting visual attention significantly improves image quality and visual comfort, with a slight advantage for real time gaze determination. Depth quality is also improved, but the difference is not significant.

GEOMETRIC AND REFLECTANCE SIGNATURE CHARACTERIZATION OF COMPLEX CANOPIES USING HYPERSPECTRAL STEREOSCOPIC IMAGES FROM UAV AND TERRESTRIAL PLATFORMS

Directory of Open Access Journals (Sweden)

E. Honkavaara

2016-06-01

Full Text Available Light-weight hyperspectral frame cameras represent novel developments in remote sensing technology. With frame camera technology, when capturing images with stereoscopic overlaps, it is possible to derive 3D hyperspectral reflectance information and 3D geometric data of targets of interest, which enables detailed geometric and radiometric characterization of the object. These technologies are expected to provide efficient tools in various environmental remote sensing applications, such as canopy classification, canopy stress analysis, precision agriculture, and urban material classification. Furthermore, these data sets enable advanced quantitative, physical based retrieval of biophysical and biochemical parameters by model inversion technologies. Objective of this investigation was to study the aspects of capturing hyperspectral reflectance data from unmanned airborne vehicle (UAV and terrestrial platform with novel hyperspectral frame cameras in complex, forested environment.

Evaluation of the Performance of Vortex Generators on the DU 91-W2-250 Profile using Stereoscopic PIV

DEFF Research Database (Denmark)

Velte, Clara Marika; Hansen, Martin Otto Laver; Meyer, Knud Erik

2009-01-01

Stereoscopic PIV measurements investigating the effect of Vortex Generators on the lift force near stall and on glide ratio at best aerodynamic performance have been carried out in the LM Glasfiber wind tunnel on a DU 91-W2-250 profile. Measurements at two Reynolds numbers were analyzed; Re=0...

Evaluation of the Performance of Vortex Generators on the DU 91-W2-250 Profile using Stereoscopic PIV

DEFF Research Database (Denmark)

Velte, Clara Marika; Hansen, Martin Otto Laver; Meyer, Knud Erik

2008-01-01

Stereoscopic PIV measurements investigating the effect of Vortex Generators on the lift force near stall and on glide ratio at best aerodynamic performance have been carried out in the LM Glasfiber wind tunnel on a DU 91-W2-250 profile. Measurements at two Reynolds numbers were analyzed; Re=0...

Stereoscopic augmented reality with pseudo-realistic global illumination effects

Science.gov (United States)

de Sorbier, Francois; Saito, Hideo

2014-03-01

Recently, augmented reality has become very popular and has appeared in our daily life with gaming, guiding systems or mobile phone applications. However, inserting object in such a way their appearance seems natural is still an issue, especially in an unknown environment. This paper presents a framework that demonstrates the capabilities of Kinect for convincing augmented reality in an unknown environment. Rather than pre-computing a reconstruction of the scene like proposed by most of the previous method, we propose a dynamic capture of the scene that allows adapting to live changes of the environment. Our approach, based on the update of an environment map, can also detect the position of the light sources. Combining information from the environment map, the light sources and the camera tracking, we can display virtual objects using stereoscopic devices with global illumination effects such as diffuse and mirror reflections, refractions and shadows in real time.

Immersive Televisual Environments: Spectatorship, Stereoscopic Vision and the Failure of 3DTV

Directory of Open Access Journals (Sweden)

Ilkin Mehrabov

2015-09-01

Full Text Available This article focuses on one of the most ground-breaking technological attempts in creating novel immersive media environments for heightened televisual user experiences: 3DTV, a Network of Excellence funded by the European Commission 6th Framework Information Society Technologies Programme. Based on the theoretical framework outlined by the works of Jonathan Crary and Brian Winston, and on empirical data obtained from author’s fieldwork and laboratory visit notes, as well as discussions with practitioners, the article explores the history of stereoscopic vision and technological progress related with it, and looks for possible reasons of 3DTV’s dramatic commercial failure.

Development of a stereoscopic three-dimensional drawing application

Science.gov (United States)

Carver, Donald E.; McAllister, David F.

1991-08-01

With recent advances in 3-D technology, computer users have the opportunity to work within a natural 3-D environment; a flat panel LCD computer display of this type, the DTI-100M made by Dimension Technologies, Inc., recently went on the market. In a joint venture between DTI and NCSU, an object-oriented 3-D drawing application, 3-D Draw, was developed to address some issues of human interface design for interactive stereo drawing applications. The focus of this paper is to determine some of the procedures a user would naturally expect to follow while working within a true 3-D environment. The paper discusses (1) the interface between the Macintosh II and DTI-100M during implementation of 3-D Draw, including stereo cursor development and presentation of current 2-D systems, with an additional `depth'' parameter, in the 3-D world, (2) problems in general for human interface into the 3-D environment, and (3) necessary functions and/or problems in developing future stereoscopic 3-D operating systems/tools.

System design description for the LDUA high resolution stereoscopic video camera system (HRSVS)

International Nuclear Information System (INIS)

Pardini, A.F.

1998-01-01

The High Resolution Stereoscopic Video Camera System (HRSVS), system 6230, was designed to be used as an end effector on the LDUA to perform surveillance and inspection activities within a waste tank. It is attached to the LDUA by means of a Tool Interface Plate (TIP) which provides a feed through for all electrical and pneumatic utilities needed by the end effector to operate. Designed to perform up close weld and corrosion inspection roles in US T operations, the HRSVS will support and supplement the Light Duty Utility Arm (LDUA) and provide the crucial inspection tasks needed to ascertain waste tank condition

Stereoscopic visualization in curved spacetime: seeing deep inside a black hole

International Nuclear Information System (INIS)

Hamilton, Andrew J S; Polhemus, Gavin

2010-01-01

Stereoscopic visualization adds an additional dimension to the viewer's experience, giving them a sense of distance. In a general relativistic visualization, distance can be measured in a variety of ways. We argue that the affine distance, which matches the usual notion of distance in flat spacetime, is a natural distance to use in curved spacetime. As an example, we apply affine distance to the visualization of the interior of a black hole. Affine distance is not the distance perceived with normal binocular vision in curved spacetime. However, the failure of binocular vision is simply a limitation of animals that have evolved in flat spacetime, not a fundamental obstacle to depth perception in curved spacetime. Trinocular vision would provide superior depth perception.

Alternation Frequency Thresholds for Stereopsis as a Technique for Exploring Stereoscopic Difficulties

Directory of Open Access Journals (Sweden)

Svetlana Rychkova

2011-01-01

Full Text Available When stereoscopic images are presented alternately to the two eyes, stereopsis occurs at F ⩾ 1 Hz full-cycle frequencies for very simple stimuli, and F ⩾ 3 Hz full-cycle frequencies for random-dot stereograms (eg Ludwig I, Pieper W, Lachnit H, 2007 “Temporal integration of monocular images separated in time: stereopsis, stereoacuity, and binocular luster” Perception & Psychophysics 69 92–102. Using twenty different stereograms presented through liquid crystal shutters, we studied the transition to stereopsis with fifteen subjects. The onset of stereopsis was observed during a stepwise increase of the alternation frequency, and its disappearance was observed during a stepwise decrease in frequency. The lowest F values (around 2.5 Hz were observed with stimuli involving two to four simple disjoint elements (circles, arcs, rectangles. Higher F values were needed for stimuli containing slanted elements or curved surfaces (about 1 Hz increment, overlapping elements at two different depths (about 2.5 Hz increment, or camouflaged overlapping surfaces (> 7 Hz increment. A textured cylindrical surface with a horizontal axis appeared easier to interpret (5.7 Hz than a pair of slanted segments separated in depth but forming a cross in projection (8 Hz. Training effects were minimal, and F usually increased as disparities were reduced. The hierarchy of difficulties revealed in the study may shed light on various problems that the brain needs to solve during stereoscopic interpretation. During the construction of the three-dimensional percept, the loss of information due to natural decay of the stimuli traces must be compensated by refreshes of visual input. In the discussion an attempt is made to link our results with recent advances in the comprehension of visual scene memory.

3-D Digitization of Stereoscopic Jet-in-Crossflow Vortex Structure Images via Augmented Reality

Science.gov (United States)

Sigurdson, Lorenz; Strand, Christopher; Watson, Graeme; Nault, Joshua; Tucker, Ryan

2006-11-01

Stereoscopic images of smoke-laden vortex flows have proven useful for understanding the topology of the embedded 3-D vortex structures. Images from two cameras allow a perception of the 3-D structure via the use of red/blue eye glasses. The human brain has an astonishing capacity to calculate and present to the observer the complex turbulent smoke volume. We have developed a technique whereby a virtual cursor is introduced to the perception, which creates an ``augmented reality.'' The perceived position of this cursor in the 3-D field can be precisely controlled by the observer. It can be brought near a characteristic vortex structure in order to digitally estimate the spatial coordinates of that feature. A calibration procedure accounts for camera positioning. Vortex tubes can be traced and recorded for later or real time supersposition of tube skeleton models. These models can be readily digitally obtained for display in graphics systems to allow complete exploration from any location or perspective. A unique feature of this technology is the use of the human brain to naturally perform the difficult computation of the shape of the translucent smoke volume. Examples are given of application to low velocity ratio and Reynolds number elevated jets-in-crossflow.

Digital stereoscopic photography using StereoData Maker

Science.gov (United States)

Toeppen, John; Sykes, David

2009-02-01

Stereoscopic digital photography has become much more practical with the use of USB wired connections between a pair of Canon cameras using StereoData Maker software for precise synchronization. StereoPhoto Maker software is now used to automatically combine and align right and left image files to produce a stereo pair. Side by side images are saved as pairs and may be viewed using software that converts the images into the preferred viewing format at the time of display. Stereo images may be shared on the internet, displayed on computer monitors, autostereo displays, viewed on high definition 3D TVs, or projected for a group. Stereo photographers are now free to control composition using point and shoot settings, or are able to control shutter speed, aperture, focus, ISO, and zoom. The quality of the output depends on the developed skills of the photographer as well as their understanding of the software, human vision and the geometry they choose for their cameras and subjects. Observers of digital stereo images can zoom in for greater detail and scroll across large panoramic fields with a few keystrokes. The art, science, and methods of taking, creating and viewing digital stereo photos are presented in a historic and developmental context in this paper.

What is stereoscopic vision good for?

Science.gov (United States)

Read, Jenny C. A.

2015-03-01

Stereo vision is a resource-intensive process. Nevertheless, it has evolved in many animals including mammals, birds, amphibians and insects. It must therefore convey significant fitness benefits. It is often assumed that the main benefit is improved accuracy of depth judgments, but camouflage breaking may be as important, particularly in predatory animals. In humans, for the last 150 years, stereo vision has been turned to a new use: helping us reproduce visual reality for artistic purposes. By recreating the different views of a scene seen by the two eyes, stereo achieves unprecedented levels of realism. However, it also has some unexpected effects on viewer experience. The disruption of established mechanisms for interpreting pictures may be one reason why some viewers find stereoscopic content disturbing. Stereo vision also has uses in ophthalmology. Clinical stereoacuity tests are used in the management of conditions such as strabismus and amblyopia as well as vision screening. Stereoacuity can reveal the effectiveness of therapy and even predict long-term outcomes post surgery. Yet current clinical stereo tests fall far short of the accuracy and precision achievable in the lab. At Newcastle University, we are exploiting the recent availability of autostereo 3D tablet computers to design a clinical stereotest app in the form of a game suitable for young children. Our goal is to enable quick, accurate and precise stereoacuity measures which will enable clinicians to obtain better outcomes for children with visual disorders.

Effect of Stereoscopic Anaglyphic 3-Dimensional Video Didactics on Learning Neuroanatomy.

Science.gov (United States)

Goodarzi, Amir; Monti, Sara; Lee, Darrin; Girgis, Fady

2017-11-01

The teaching of neuroanatomy in medical education has historically been based on didactic instruction, cadaveric dissections, and intraoperative experience for students. Multiple novel 3-dimensional (3D) modalities have recently emerged. Among these, stereoscopic anaglyphic video is easily accessible and affordable, however, its effects have not yet formally been investigated. This study aimed to investigate if 3D stereoscopic anaglyphic video instruction in neuroanatomy could improve learning for content-naive students, as compared with 2-dimensional (2D) video instruction. A single-site controlled prospective case control study was conducted at the School of Education. Content knowledge was assessed at baseline, followed by the presentation of an instructional neuroanatomy video. Participants viewed the video in either 2D or 3D format and then completed a written test of skull base neuroanatomy. Pretest and post-test performances were analyzed with independent Student's t-tests and analysis of covariance. Our study was completed by 249 subjects. At baseline, the 2D (n = 124, F = 97) and 3D groups (n = 125, F = 96) were similar, although the 3D group was older by 1.7 years (P = 0.0355) and the curricula of participating classes differed (P < 0.0001). Average scores for the 3D group were higher for both pretest (2D, M = 19.9%, standard deviation [SD] = 12.5% vs. 3D, M = 23.9%, SD = 14.9%, P = 0.0234) and post-test performances (2D, M = 68.5%, SD = 18.6% vs. 3D, M = 77.3%, SD = 18.8%, P = 0.003), but the magnitude of improvement across groups did not reach statistical significance (2D, M = 48.7%, SD = 21.3%, vs. 3D, M = 53.5%, SD = 22.7%, P = 0.0855). Incorporation of 3D video instruction into curricula without careful integration is insufficient to promote learning over 2D video. Published by Elsevier Inc.

Assessing the precision of gaze following using a stereoscopic 3D virtual reality setting.

Science.gov (United States)

Atabaki, Artin; Marciniak, Karolina; Dicke, Peter W; Thier, Peter

2015-07-01

Despite the ecological importance of gaze following, little is known about the underlying neuronal processes, which allow us to extract gaze direction from the geometric features of the eye and head of a conspecific. In order to understand the neuronal mechanisms underlying this ability, a careful description of the capacity and the limitations of gaze following at the behavioral level is needed. Previous studies of gaze following, which relied on naturalistic settings have the disadvantage of allowing only very limited control of potentially relevant visual features guiding gaze following, such as the contrast of iris and sclera, the shape of the eyelids and--in the case of photographs--they lack depth. Hence, in order to get full control of potentially relevant features we decided to study gaze following of human observers guided by the gaze of a human avatar seen stereoscopically. To this end we established a stereoscopic 3D virtual reality setup, in which we tested human subjects' abilities to detect at which target a human avatar was looking at. Following the gaze of the avatar showed all the features of the gaze following of a natural person, namely a substantial degree of precision associated with a consistent pattern of systematic deviations from the target. Poor stereo vision affected performance surprisingly little (only in certain experimental conditions). Only gaze following guided by targets at larger downward eccentricities exhibited a differential effect of the presence or absence of accompanying movements of the avatar's eyelids and eyebrows. Copyright © 2015 Elsevier Ltd. All rights reserved.

Analysis of scene distortions in stereoscopic images due to the variation of the ideal viewing conditions

Science.gov (United States)

Viale, Alberto; Villa, Dario

2011-03-01

Recently stereoscopy has increased a lot its popularity and various technologies are spreading in theaters and homes allowing observation of stereoscopic images and movies, becoming affordable even for home users. However there are some golden rules that users should follow to ensure a better enjoyment of stereoscopic images, first of all the viewing condition should not be too different from the ideal ones, which were assumed during the production process. To allow the user to perceive stereo depth instead of a flat image, two different views of the same scene are shown to the subject, one is seen just through his left eye and the other just through the right one; the vision process is making the work of merging the two images in a virtual three-dimensional scene, giving to the user the perception of depth. The two images presented to the user were created, either from image synthesis or from more traditional techniques, following the rules of perspective. These rules need some boundary conditions to be explicit, such as eye separation, field of view, parallax distance, viewer position and orientation. In this paper we are interested in studying how the variation of the viewer position and orientation from the ideal ones expressed as specified parameters in the image creation process, is affecting the correctness of the reconstruction of the three-dimensional virtual scene.

Surgical approaches to complex vascular lesions: the use of virtual reality and stereoscopic analysis as a tool for resident and student education.

Science.gov (United States)

Agarwal, Nitin; Schmitt, Paul J; Sukul, Vishad; Prestigiacomo, Charles J

2012-08-01

Virtual reality training for complex tasks has been shown to be of benefit in fields involving highly technical and demanding skill sets. The use of a stereoscopic three-dimensional (3D) virtual reality environment to teach a patient-specific analysis of the microsurgical treatment modalities of a complex basilar aneurysm is presented. Three different surgical approaches were evaluated in a virtual environment and then compared to elucidate the best surgical approach. These approaches were assessed with regard to the line-of-sight, skull base anatomy and visualisation of the relevant anatomy at the level of the basilar artery and surrounding structures. Overall, the stereoscopic 3D virtual reality environment with fusion of multimodality imaging affords an excellent teaching tool for residents and medical students to learn surgical approaches to vascular lesions. Future studies will assess the educational benefits of this modality and develop a series of metrics for student assessments.

Measurement of compressed breast thickness by optical stereoscopic photogrammetry.

Science.gov (United States)

Tyson, Albert H; Mawdsley, Gordon E; Yaffe, Martin J

2009-02-01

The determination of volumetric breast density (VBD) from mammograms requires accurate knowledge of the thickness of the compressed breast. In attempting to accurately determine VBD from images obtained on conventional mammography systems, the authors found that the thickness reported by a number of mammography systems in the field varied by as much as 15 mm when compressing the same breast or phantom. In order to evaluate the behavior of mammographic compression systems and to be able to predict the thickness at different locations in the breast on patients, they have developed a method for measuring the local thickness of the breast at all points of contact with the compression paddle using optical stereoscopic photogrammetry. On both flat (solid) and compressible phantoms, the measurements were accurate to better than 1 mm with a precision of 0.2 mm. In a pilot study, this method was used to measure thickness on 108 volunteers who were undergoing mammography examination. This measurement tool will allow us to characterize paddle surface deformations, deflections and calibration offsets for mammographic units.

Stereoscopic, thermal, and true deep cumulus cloud top heights

Science.gov (United States)

Llewellyn-Jones, D. T.; Corlett, G. K.; Lawrence, S. P.; Remedios, J. J.; Sherwood, S. C.; Chae, J.; Minnis, P.; McGill, M.

2004-05-01

We compare cloud-top height estimates from several sensors: thermal tops from GOES-8 and MODIS, stereoscopic tops from MISR, and directly measured heights from the Goddard Cloud Physics Lidar on board the ER-2, all collected during the CRYSTAL-FACE field campaign. Comparisons reveal a persistent 1-2 km underestimation of cloud-top heights by thermal imagery, even when the finite optical extinctions near cloud top and in thin overlying cirrus are taken into account. The most severe underestimates occur for the tallest clouds. The MISR "best-sinds" and lidar estimates disagree in very similar ways with thermally estimated tops, which we take as evidence of excellent performance by MISR. Encouraged by this, we use MISR to examine variations in cloud penetration and thermal top height errors in several locations of tropical deep convection over multiple seasons. The goals of this are, first, to learn how cloud penetration depends on the near-tropopause environment; and second, to gain further insight into the mysterious underestimation of tops by thermal imagery.

ESTABLISHING A STEREOSCOPIC TECHNIQUE FOR DETERMINING THE KINEMATIC PROPERTIES OF SOLAR WIND TRANSIENTS BASED ON A GENERALIZED SELF-SIMILARLY EXPANDING CIRCULAR GEOMETRY

International Nuclear Information System (INIS)

Davies, J. A.; Perry, C. H.; Harrison, R. A.; Trines, R. M. G. M.; Lugaz, N.; Möstl, C.; Liu, Y. D.; Steed, K.

2013-01-01

The twin-spacecraft STEREO mission has enabled simultaneous white-light imaging of the solar corona and inner heliosphere from multiple vantage points. This has led to the development of numerous stereoscopic techniques to investigate the three-dimensional structure and kinematics of solar wind transients such as coronal mass ejections (CMEs). Two such methods—triangulation and the tangent to a sphere—can be used to determine time profiles of the propagation direction and radial distance (and thereby radial speed) of a solar wind transient as it travels through the inner heliosphere, based on its time-elongation profile viewed by two observers. These techniques are founded on the assumption that the transient can be characterized as a point source (fixed φ, FP, approximation) or a circle attached to Sun-center (harmonic mean, HM, approximation), respectively. These geometries constitute extreme descriptions of solar wind transients, in terms of their cross-sectional extent. Here, we present the stereoscopic expressions necessary to derive propagation direction and radial distance/speed profiles of such transients based on the more generalized self-similar expansion (SSE) geometry, for which the FP and HM geometries form the limiting cases; our implementation of these equations is termed the stereoscopic SSE method. We apply the technique to two Earth-directed CMEs from different phases of the STEREO mission, the well-studied event of 2008 December and a more recent event from 2012 March. The latter CME was fast, with an initial speed exceeding 2000 km s –1 , and highly geoeffective, in stark contrast to the slow and ineffectual 2008 December CME

Stereoscopic HDTV Research at NHK Science and Technology Research Laboratories

CERN Document Server

Yamanoue, Hirokazu; Nojiri, Yuji

2012-01-01

This book focuses on the two psychological factors of naturalness and ease of viewing of three-dimensional high-definition television (3D HDTV) images. It has been said that distortions peculiar to stereoscopic images, such as the “puppet theater” effect or the “cardboard” effect, spoil the sense of presence. Whereas many earlier studies have focused on geometrical calculations about these distortions, this book instead describes the relationship between the naturalness of reproduced 3D HDTV images and the nonlinearity of depthwise reproduction. The ease of viewing of each scene is regarded as one of the causal factors of visual fatigue. Many of the earlier studies have been concerned with the accurate extraction of local parallax; however, this book describes the typical spatiotemporal distribution of parallax in 3D images. The purpose of the book is to examine the correlations between the psychological factors and amount of characteristics of parallax distribution in order to understand the characte...

Remote stereoscopic video play platform for naked eyes based on the Android system

Science.gov (United States)

Jia, Changxin; Sang, Xinzhu; Liu, Jing; Cheng, Mingsheng

2014-11-01

As people's life quality have been improved significantly, the traditional 2D video technology can not meet people's urgent desire for a better video quality, which leads to the rapid development of 3D video technology. Simultaneously people want to watch 3D video in portable devices,. For achieving the above purpose, we set up a remote stereoscopic video play platform. The platform consists of a server and clients. The server is used for transmission of different formats of video and the client is responsible for receiving remote video for the next decoding and pixel restructuring. We utilize and improve Live555 as video transmission server. Live555 is a cross-platform open source project which provides solutions for streaming media such as RTSP protocol and supports transmission of multiple video formats. At the receiving end, we use our laboratory own player. The player for Android, which is with all the basic functions as the ordinary players do and able to play normal 2D video, is the basic structure for redevelopment. Also RTSP is implemented into this structure for telecommunication. In order to achieve stereoscopic display, we need to make pixel rearrangement in this player's decoding part. The decoding part is the local code which JNI interface calls so that we can extract video frames more effectively. The video formats that we process are left and right, up and down and nine grids. In the design and development, a large number of key technologies from Android application development have been employed, including a variety of wireless transmission, pixel restructuring and JNI call. By employing these key technologies, the design plan has been finally completed. After some updates and optimizations, the video player can play remote 3D video well anytime and anywhere and meet people's requirement.

Stereoscopic Machine-Vision System Using Projected Circles

Science.gov (United States)

Mackey, Jeffrey R.

2010-01-01

A machine-vision system capable of detecting obstacles large enough to damage or trap a robotic vehicle is undergoing development. The system includes (1) a pattern generator that projects concentric circles of laser light forward onto the terrain, (2) a stereoscopic pair of cameras that are aimed forward to acquire images of the circles, (3) a frame grabber and digitizer for acquiring image data from the cameras, and (4) a single-board computer that processes the data. The system is being developed as a prototype of machine- vision systems to enable robotic vehicles ( rovers ) on remote planets to avoid craters, large rocks, and other terrain features that could capture or damage the vehicles. Potential terrestrial applications of systems like this one could include terrain mapping, collision avoidance, navigation of robotic vehicles, mining, and robotic rescue. This system is based partly on the same principles as those of a prior stereoscopic machine-vision system in which the cameras acquire images of a single stripe of laser light that is swept forward across the terrain. However, this system is designed to afford improvements over some of the undesirable features of the prior system, including the need for a pan-and-tilt mechanism to aim the laser to generate the swept stripe, ambiguities in interpretation of the single-stripe image, the time needed to sweep the stripe across the terrain and process the data from many images acquired during that time, and difficulty of calibration because of the narrowness of the stripe. In this system, the pattern generator does not contain any moving parts and need not be mounted on a pan-and-tilt mechanism: the pattern of concentric circles is projected steadily in the forward direction. The system calibrates itself by use of data acquired during projection of the concentric-circle pattern onto a known target representing flat ground. The calibration- target image data are stored in the computer memory for use as a

Relationship between Stereoscopic Vision, Visual Perception, and Microstructure Changes of Corpus Callosum and Occipital White Matter in the 4-Year-Old Very Low Birth Weight Children

Directory of Open Access Journals (Sweden)

Przemko Kwinta

2015-01-01

Full Text Available Aim. To assess the relationship between stereoscopic vision, visual perception, and microstructure of the corpus callosum (CC and occipital white matter, 61 children born with a mean birth weight of 1024 g (SD 270 g were subjected to detailed ophthalmologic evaluation, Developmental Test of Visual Perception (DTVP-3, and diffusion tensor imaging (DTI at the age of 4. Results. Abnormal stereoscopic vision was detected in 16 children. Children with abnormal stereoscopic vision had smaller CC (CC length: 53±6 mm versus 61±4 mm; p<0.01; estimated CC area: 314±106 mm2 versus 446±79 mm2; p<0.01 and lower fractional anisotropy (FA values in CC (FA value of rostrum/genu: 0.7±0.09 versus 0.79±0.07; p<0.01; FA value of CC body: 0.74±0.13 versus 0.82±0.09; p=0.03. We found a significant correlation between DTVP-3 scores, CC size, and FA values in rostrum and body. This correlation was unrelated to retinopathy of prematurity. Conclusions. Visual perceptive dysfunction in ex-preterm children without major sequelae of prematurity depends on more subtle changes in the brain microstructure, including CC. Role of interhemispheric connections in visual perception might be more complex than previously anticipated.

Real-time Stereoscopic 3D for E-Robotics Learning

Directory of Open Access Journals (Sweden)

Richard Y. Chiou

2011-02-01

Full Text Available Following the design and testing of a successful 3-Dimensional surveillance system, this 3D scheme has been implemented into online robotics learning at Drexel University. A real-time application, utilizing robot controllers, programmable logic controllers and sensors, has been developed in the “MET 205 Robotics and Mechatronics” class to provide the students with a better robotic education. The integration of the 3D system allows the students to precisely program the robot and execute functions remotely. Upon the students’ recommendation, polarization has been chosen to be the main platform behind the 3D robotic system. Stereoscopic calculations are carried out for calibration purposes to display the images with the highest possible comfort-level and 3D effect. The calculations are further validated by comparing the results with students’ evaluations. Due to the Internet-based feature, multiple clients have the opportunity to perform the online automation development. In the future, students, in different universities, will be able to cross-control robotic components of different types around the world. With the development of this 3D ERobotics interface, automation resources and robotic learning can be shared and enriched regardless of location.

Attack of the S. Mutans!: a stereoscopic-3D multiplayer direct-manipulation behavior-modification serious game for improving oral health in pre-teens

Science.gov (United States)

Hollander, Ari; Rose, Howard; Kollin, Joel; Moss, William

2011-03-01

Attack! of the S. Mutans is a multi-player game designed to harness the immersion and appeal possible with wide-fieldof- view stereoscopic 3D to combat the tooth decay epidemic. Tooth decay is one of the leading causes of school absences and costs more than $100B annually in the U.S. In 2008 the authors received a grant from the National Institutes of Health to build a science museum exhibit that included a suite of serious games involving the behaviors and bacteria that cause cavities. The centerpiece is an adventure game where five simultaneous players use modified Wii controllers to battle biofilms and bacteria while immersed in environments generated within a 11-foot stereoscopic WUXGA display. The authors describe the system and interface used in this prototype application and some of the ways they attempted to use the power of immersion and the appeal of S3D revolution to change health attitudes and self-care habits.

Stereoscopic Augmented Reality System for Supervised Training on Minimal Invasive Surgery Robots

DEFF Research Database (Denmark)

Matu, Florin-Octavian; Thøgersen, Mikkel; Galsgaard, Bo

2014-01-01

the need for efficient training. When training with the robot, the communication between the trainer and the trainee is limited, since the trainee often cannot see the trainer. To overcome this issue, this paper proposes an Augmented Reality (AR) system where the trainer is controlling two virtual robotic...... arms. These arms are virtually superimposed on the video feed to the trainee, and can therefore be used to demonstrate and perform various tasks for the trainee. Furthermore, the trainer is presented with a 3D image through a stereoscopic display. Because of the added depth perception, this enables...... the procedure, and thereby enhances the training experience. The virtual overlay was also found to work as a good and illustrative approach for enhanced communication. However, the delay of the prototype made it difficult to use for actual training....

Stereoscopic vision in the absence of the lateral occipital cortex.

Directory of Open Access Journals (Sweden)

Jenny C A Read

2010-09-01

Full Text Available Both dorsal and ventral cortical visual streams contain neurons sensitive to binocular disparities, but the two streams may underlie different aspects of stereoscopic vision. Here we investigate stereopsis in the neurological patient D.F., whose ventral stream, specifically lateral occipital cortex, has been damaged bilaterally, causing profound visual form agnosia. Despite her severe damage to cortical visual areas, we report that DF's stereo vision is strikingly unimpaired. She is better than many control observers at using binocular disparity to judge whether an isolated object appears near or far, and to resolve ambiguous structure-from-motion. DF is, however, poor at using relative disparity between features at different locations across the visual field. This may stem from a difficulty in identifying the surface boundaries where relative disparity is available. We suggest that the ventral processing stream may play a critical role in enabling healthy observers to extract fine depth information from relative disparities within one surface or between surfaces located in different parts of the visual field.

Augmented reality to the rescue of the minimally invasive surgeon. The usefulness of the interposition of stereoscopic images in the Da Vinci™ robotic console.

Science.gov (United States)

Volonté, Francesco; Buchs, Nicolas C; Pugin, François; Spaltenstein, Joël; Schiltz, Boris; Jung, Minoa; Hagen, Monika; Ratib, Osman; Morel, Philippe

2013-09-01

Computerized management of medical information and 3D imaging has become the norm in everyday medical practice. Surgeons exploit these emerging technologies and bring information previously confined to the radiology rooms into the operating theatre. The paper reports the authors' experience with integrated stereoscopic 3D-rendered images in the da Vinci surgeon console. Volume-rendered images were obtained from a standard computed tomography dataset using the OsiriX DICOM workstation. A custom OsiriX plugin was created that permitted the 3D-rendered images to be displayed in the da Vinci surgeon console and to appear stereoscopic. These rendered images were displayed in the robotic console using the TilePro multi-input display. The upper part of the screen shows the real endoscopic surgical field and the bottom shows the stereoscopic 3D-rendered images. These are controlled by a 3D joystick installed on the console, and are updated in real time. Five patients underwent a robotic augmented reality-enhanced procedure. The surgeon was able to switch between the classical endoscopic view and a combined virtual view during the procedure. Subjectively, the addition of the rendered images was considered to be an undeniable help during the dissection phase. With the rapid evolution of robotics, computer-aided surgery is receiving increasing interest. This paper details the authors' experience with 3D-rendered images projected inside the surgical console. The use of this intra-operative mixed reality technology is considered very useful by the surgeon. It has been shown that the usefulness of this technique is a step toward computer-aided surgery that will progress very quickly over the next few years. Copyright © 2012 John Wiley & Sons, Ltd.

STEREOMETRIC MODELLING

Directory of Open Access Journals (Sweden)

P. Grimaldi

2012-07-01

Full Text Available These mandatory guidelines are provided for preparation of papers accepted for publication in the series of Volumes of The The stereometric modelling means modelling achieved with : – the use of a pair of virtual cameras, with parallel axes and positioned at a mutual distance average of 1/10 of the distance camera-object (in practice the realization and use of a stereometric camera in the modeling program; – the shot visualization in two distinct windows – the stereoscopic viewing of the shot while modelling. Since the definition of "3D vision" is inaccurately referred to as the simple perspective of an object, it is required to add the word stereo so that "3D stereo vision " shall stand for "three-dimensional view" and ,therefore, measure the width, height and depth of the surveyed image. Thanks to the development of a stereo metric model , either real or virtual, through the "materialization", either real or virtual, of the optical-stereo metric model made visible with a stereoscope. It is feasible a continuous on line updating of the cultural heritage with the help of photogrammetry and stereometric modelling. The catalogue of the Architectonic Photogrammetry Laboratory of Politecnico di Bari is available on line at: http://rappresentazione.stereofot.it:591/StereoFot/FMPro?-db=StereoFot.fp5&-lay=Scheda&-format=cerca.htm&-view

3D pressure imaging of an aircraft propeller blade-tip flow by phase-locked stereoscopic PIV

Energy Technology Data Exchange (ETDEWEB)

Ragni, D.; Oudheusden, B.W. van; Scarano, F. [Delft University of Technology, Faculty of Aerospace Engineering, Delft (Netherlands)

2012-02-15

The flow field at the tip region of a scaled DHC Beaver aircraft propeller, running at transonic speed, has been investigated by means of a multi-plane stereoscopic particle image velocimetry setup. Velocity fields, phase-locked with the blade rotational motion, are acquired across several planes perpendicular to the blade axis and merged to form a 3D measurement volume. Transonic conditions have been reached at the tip region, with a revolution frequency of 19,800 rpm and a relative free-stream Mach number of 0.73 at the tip. The pressure field and the surface pressure distribution are inferred from the 3D velocity data through integration of the momentum Navier-Stokes equation in differential form, allowing for the simultaneous flow visualization and the aerodynamic loads computation, with respect to a reference frame moving with the blade. The momentum and pressure data are further integrated by means of a contour-approach to yield the aerodynamic sectional force components as well as the blade torsional moment. A steady Reynolds averaged Navier-Stokes numerical simulation of the entire propeller model has been used for comparison to the measurement data. (orig.)

3D pressure imaging of an aircraft propeller blade-tip flow by phase-locked stereoscopic PIV

Science.gov (United States)

Ragni, D.; van Oudheusden, B. W.; Scarano, F.

2012-02-01

The flow field at the tip region of a scaled DHC Beaver aircraft propeller, running at transonic speed, has been investigated by means of a multi-plane stereoscopic particle image velocimetry setup. Velocity fields, phase-locked with the blade rotational motion, are acquired across several planes perpendicular to the blade axis and merged to form a 3D measurement volume. Transonic conditions have been reached at the tip region, with a revolution frequency of 19,800 rpm and a relative free-stream Mach number of 0.73 at the tip. The pressure field and the surface pressure distribution are inferred from the 3D velocity data through integration of the momentum Navier-Stokes equation in differential form, allowing for the simultaneous flow visualization and the aerodynamic loads computation, with respect to a reference frame moving with the blade. The momentum and pressure data are further integrated by means of a contour-approach to yield the aerodynamic sectional force components as well as the blade torsional moment. A steady Reynolds averaged Navier-Stokes numerical simulation of the entire propeller model has been used for comparison to the measurement data.

Streaming video-based 3D reconstruction method compatible with existing monoscopic and stereoscopic endoscopy systems

Science.gov (United States)

Bouma, Henri; van der Mark, Wannes; Eendebak, Pieter T.; Landsmeer, Sander H.; van Eekeren, Adam W. M.; ter Haar, Frank B.; Wieringa, F. Pieter; van Basten, Jean-Paul

2012-06-01

Compared to open surgery, minimal invasive surgery offers reduced trauma and faster recovery. However, lack of direct view limits space perception. Stereo-endoscopy improves depth perception, but is still restricted to the direct endoscopic field-of-view. We describe a novel technology that reconstructs 3D-panoramas from endoscopic video streams providing a much wider cumulative overview. The method is compatible with any endoscope. We demonstrate that it is possible to generate photorealistic 3D-environments from mono- and stereoscopic endoscopy. The resulting 3D-reconstructions can be directly applied in simulators and e-learning. Extended to real-time processing, the method looks promising for telesurgery or other remote vision-guided tasks.

The Advanced Gamma-ray Imaging System (AGIS): Real Time Stereoscopic Array Trigger

Science.gov (United States)

Byrum, K.; Anderson, J.; Buckley, J.; Cundiff, T.; Dawson, J.; Drake, G.; Duke, C.; Haberichter, B.; Krawzcynski, H.; Krennrich, F.; Madhavan, A.; Schroedter, M.; Smith, A.

2009-05-01

Future large arrays of Imaging Atmospheric Cherenkov telescopes (IACTs) such as AGIS and CTA are conceived to comprise of 50 - 100 individual telescopes each having a camera with 10**3 to 10**4 pixels. To maximize the capabilities of such IACT arrays with a low energy threshold, a wide field of view and a low background rate, a sophisticated array trigger is required. We describe the design of a stereoscopic array trigger that calculates image parameters and then correlates them across a subset of telescopes. Fast Field Programmable Gate Array technology allows to use lookup tables at the array trigger level to form a real-time pattern recognition trigger tht capitalizes on the multiple view points of the shower at different shower core distances. A proof of principle system is currently under construction. It is based on 400 MHz FPGAs and the goal is for camera trigger rates of up to 10 MHz and a tunable cosmic-ray background suppression at the array level.

Formalizing the potential of stereoscopic 3D user experience in interactive entertainment

Science.gov (United States)

Schild, Jonas; Masuch, Maic

2015-03-01

The use of stereoscopic 3D vision affects how interactive entertainment has to be developed as well as how it is experienced by the audience. The large amount of possibly impacting factors and variety as well as a certain subtlety of measured effects on user experience make it difficult to grasp the overall potential of using S3D vision. In a comprehensive approach, we (a) present a development framework which summarizes possible variables in display technology, content creation and human factors, and (b) list a scheme of S3D user experience effects concerning initial fascination, emotions, performance, and behavior as well as negative feelings of discomfort and complexity. As a major contribution we propose a qualitative formalization which derives dependencies between development factors and user effects. The argumentation is based on several previously published user studies. We further show how to apply this formula to identify possible opportunities and threats in content creation as well as how to pursue future steps for a possible quantification.

iCAVE: an open source tool for visualizing biomolecular networks in 3D, stereoscopic 3D and immersive 3D.

Science.gov (United States)

Liluashvili, Vaja; Kalayci, Selim; Fluder, Eugene; Wilson, Manda; Gabow, Aaron; Gümüs, Zeynep H

2017-08-01

Visualizations of biomolecular networks assist in systems-level data exploration in many cellular processes. Data generated from high-throughput experiments increasingly inform these networks, yet current tools do not adequately scale with concomitant increase in their size and complexity. We present an open source software platform, interactome-CAVE (iCAVE), for visualizing large and complex biomolecular interaction networks in 3D. Users can explore networks (i) in 3D using a desktop, (ii) in stereoscopic 3D using 3D-vision glasses and a desktop, or (iii) in immersive 3D within a CAVE environment. iCAVE introduces 3D extensions of known 2D network layout, clustering, and edge-bundling algorithms, as well as new 3D network layout algorithms. Furthermore, users can simultaneously query several built-in databases within iCAVE for network generation or visualize their own networks (e.g., disease, drug, protein, metabolite). iCAVE has modular structure that allows rapid development by addition of algorithms, datasets, or features without affecting other parts of the code. Overall, iCAVE is the first freely available open source tool that enables 3D (optionally stereoscopic or immersive) visualizations of complex, dense, or multi-layered biomolecular networks. While primarily designed for researchers utilizing biomolecular networks, iCAVE can assist researchers in any field. © The Authors 2017. Published by Oxford University Press.

Stereoscopic three-dimensional images of an anatomical dissection of the eyeball and orbit for educational purposes.

Science.gov (United States)

Matsuo, Toshihiko; Takeda, Yoshimasa; Ohtsuka, Aiji

2013-01-01

The purpose of this study was to develop a series of stereoscopic anatomical images of the eye and orbit for use in the curricula of medical schools and residency programs in ophthalmology and other specialties. Layer-by-layer dissection of the eyelid, eyeball, and orbit of a cadaver was performed by an ophthalmologist. A stereoscopic camera system was used to capture a series of anatomical views that were scanned in a panoramic three-dimensional manner around the center of the lid fissure. The images could be rotated 360 degrees in the frontal plane and the angle of views could be tilted up to 90 degrees along the anteroposterior axis perpendicular to the frontal plane around the 360 degrees. The skin, orbicularis oculi muscle, and upper and lower tarsus were sequentially observed. The upper and lower eyelids were removed to expose the bulbar conjunctiva and to insert three 25-gauge trocars for vitrectomy at the location of the pars plana. The cornea was cut at the limbus, and the lens with mature cataract was dislocated. The sclera was cut to observe the trocars from inside the eyeball. The sclera was further cut to visualize the superior oblique muscle with the trochlea and the inferior oblique muscle. The eyeball was dissected completely to observe the optic nerve and the ophthalmic artery. The thin bones of the medial and inferior orbital wall were cracked with a forceps to expose the ethmoid and maxillary sinus, respectively. In conclusion, the serial dissection images visualized aspects of the local anatomy specific to various procedures, including the levator muscle and tarsus for blepharoptosis surgery, 25-gauge trocars as viewed from inside the eye globe for vitrectomy, the oblique muscles for strabismus surgery, and the thin medial and inferior orbital bony walls for orbital bone fractures.

Stereoscopic radiographic images with gamma source encoding

International Nuclear Information System (INIS)

Strocovsky, S.G.; Otero, D

2012-01-01

Conventional radiography with X-ray tube has several drawbacks, as the compromise between the size of the focal spot and the fluence. The finite dimensions of the focal spot impose a limit to the spatial resolution. Gamma radiography uses gamma-ray sources which surpass in size, portability and simplicity to X-ray tubes. However, its low intrinsic fluence forces to use extended sources that also degrade the spatial resolution. In this work, we show the principles of a new radiographic technique that overcomes the limitations associated with the finite dimensions of X-ray sources, and that offers additional benefits to conventional techniques. The new technique called coding source imaging (CSI), is based on the use of extended sources, edge-encoding of radiation and differential detection. The mathematical principles and the method of images reconstruction with the new proposed technique are explained in the present work. Analytical calculations were made to determine the maximum spatial resolution and the variables on which it depends. The CSI technique was tested by means of Monte Carlo simulations with sets of spherical objects. We show that CSI has stereoscopic capabilities and it can resolve objects smaller than the source size. The CSI decoding algorithm reconstructs simultaneously four different projections from the same object, while conventional radiography produces only one projection per acquisition. Projections are located in separate image fields on the detector plane. Our results show it is possible to apply an extremely simple radiographic technique with extended sources, and get 3D information of the attenuation coefficient distribution for simple geometry objects in a single acquisition. The results are promising enough to evaluate the possibility of future research with more complex objects typical of medical diagnostic radiography and industrial gamma radiography (author)

Setup accuracy of stereoscopic X-ray positioning with automated correction for rotational errors in patients treated with conformal arc radiotherapy for prostate cancer

International Nuclear Information System (INIS)

Soete, Guy; Verellen, Dirk; Tournel, Koen; Storme, Guy

2006-01-01

We evaluated setup accuracy of NovalisBody stereoscopic X-ray positioning with automated correction for rotational errors with the Robotics Tilt Module in patients treated with conformal arc radiotherapy for prostate cancer. The correction of rotational errors was shown to reduce random and systematic errors in all directions. (NovalisBody TM and Robotics Tilt Module TM are products of BrainLAB A.G., Heimstetten, Germany)

Measurements of turbulent premixed flame dynamics using cinema stereoscopic PIV

Energy Technology Data Exchange (ETDEWEB)

Steinberg, Adam M.; Driscoll, James F. [University of Michigan, Department of Aerospace Engineering, Ann Arbor, MI (United States); Ceccio, Steven L. [University of Michigan, Department of Mechanical Engineering, Ann Arbor, MI (United States)

2008-06-15

A new experimental method is described that provides high-speed movies of turbulent premixed flame wrinkling dynamics and the associated vorticity fields. This method employs cinema stereoscopic particle image velocimetry and has been applied to a turbulent slot Bunsen flame. Three-component velocity fields were measured with high temporal and spatial resolutions of 0.9 ms and 140{mu}m, respectively. The flame-front location was determined using a new multi-step method based on particle image gradients, which is described. Comparisons are made between flame fronts found with this method and simultaneous CH-PLIF images. These show that the flame contour determined corresponds well to the true location of maximum gas density gradient. Time histories of typical eddy-flame interactions are reported and several important phenomena identified. Outwardly rotating eddy pairs wrinkle the flame and are attenuated at they pass through the flamelet. Significant flame-generated vorticity is produced downstream of the wrinkled tip. Similar wrinkles are caused by larger groups of outwardly rotating eddies. Inwardly rotating pairs cause significant convex wrinkles that grow as the flame propagates. These wrinkles encounter other eddies that alter their behavior. The effects of the hydrodynamic and diffusive instabilities are observed and found to be significant contributors to the formation and propagation of wrinkles. (orig.)

Robust and Accurate Algorithm for Wearable Stereoscopic Augmented Reality with Three Indistinguishable Markers

Directory of Open Access Journals (Sweden)

Fabrizio Cutolo

2016-09-01

Full Text Available In the context of surgical navigation systems based on augmented reality (AR, the key challenge is to ensure the highest degree of realism in merging computer-generated elements with live views of the surgical scene. This paper presents an algorithm suited for wearable stereoscopic augmented reality video see-through systems for use in a clinical scenario. A video-based tracking solution is proposed that relies on stereo localization of three monochromatic markers rigidly constrained to the scene. A PnP-based optimization step is introduced to refine separately the pose of the two cameras. Video-based tracking methods using monochromatic markers are robust to non-controllable and/or inconsistent lighting conditions. The two-stage camera pose estimation algorithm provides sub-pixel registration accuracy. From a technological and an ergonomic standpoint, the proposed approach represents an effective solution to the implementation of wearable AR-based surgical navigation systems wherever rigid anatomies are involved.

Stereoscopic radiographic images with thermal neutrons

Science.gov (United States)

Silvani, M. I.; Almeida, G. L.; Rogers, J. D.; Lopes, R. T.

2011-10-01

Spatial structure of an object can be perceived by the stereoscopic vision provided by eyes or by the parallax produced by movement of the object with regard to the observer. For an opaque object, a technique to render it transparent should be used, in order to make visible the spatial distribution of its inner structure, for any of the two approaches used. In this work, a beam of thermal neutrons at the main port of the Argonauta research reactor of the Instituto de Engenharia Nuclear in Rio de Janeiro/Brazil has been used as radiation to render the inspected objects partially transparent. A neutron sensitive Imaging Plate has been employed as a detector and after exposure it has been developed by a reader using a 0.5 μm laser beam, which defines the finest achievable spatial resolution of the acquired digital image. This image, a radiographic attenuation map of the object, does not represent any specific cross-section but a convoluted projection for each specific attitude of the object with regard to the detector. After taking two of these projections at different object attitudes, they are properly processed and the final image is viewed by a red and green eyeglass. For monochromatic images this processing involves transformation of black and white radiographies into red and white and green and white ones, which are afterwards merged to yield a single image. All the processes are carried out with the software ImageJ. Divergence of the neutron beam unfortunately spoils both spatial and contrast resolutions, which become poorer as object-detector distance increases. Therefore, in order to evaluate the range of spatial resolution corresponding to the 3D image being observed, a curve expressing spatial resolution against object-detector gap has been deduced from the Modulation Transfer Functions experimentally. Typical exposure times, under a reactor power of 170 W, were 6 min for both quantitative and qualitative measurements. In spite of its intrinsic constraints

Stereoscopic radiographic images with thermal neutrons

International Nuclear Information System (INIS)

Silvani, M.I.; Almeida, G.L.; Rogers, J.D.; Lopes, R.T.

2011-01-01

Spatial structure of an object can be perceived by the stereoscopic vision provided by eyes or by the parallax produced by movement of the object with regard to the observer. For an opaque object, a technique to render it transparent should be used, in order to make visible the spatial distribution of its inner structure, for any of the two approaches used. In this work, a beam of thermal neutrons at the main port of the Argonauta research reactor of the Instituto de Engenharia Nuclear in Rio de Janeiro/Brazil has been used as radiation to render the inspected objects partially transparent. A neutron sensitive Imaging Plate has been employed as a detector and after exposure it has been developed by a reader using a 0.5 μm laser beam, which defines the finest achievable spatial resolution of the acquired digital image. This image, a radiographic attenuation map of the object, does not represent any specific cross-section but a convoluted projection for each specific attitude of the object with regard to the detector. After taking two of these projections at different object attitudes, they are properly processed and the final image is viewed by a red and green eyeglass. For monochromatic images this processing involves transformation of black and white radiographies into red and white and green and white ones, which are afterwards merged to yield a single image. All the processes are carried out with the software ImageJ. Divergence of the neutron beam unfortunately spoils both spatial and contrast resolutions, which become poorer as object-detector distance increases. Therefore, in order to evaluate the range of spatial resolution corresponding to the 3D image being observed, a curve expressing spatial resolution against object-detector gap has been deduced from the Modulation Transfer Functions experimentally. Typical exposure times, under a reactor power of 170 W, were 6 min for both quantitative and qualitative measurements. In spite of its intrinsic constraints

Augmented reality during robot-assisted laparoscopic partial nephrectomy: toward real-time 3D-CT to stereoscopic video registration.

Science.gov (United States)

Su, Li-Ming; Vagvolgyi, Balazs P; Agarwal, Rahul; Reiley, Carol E; Taylor, Russell H; Hager, Gregory D

2009-04-01

To investigate a markerless tracking system for real-time stereo-endoscopic visualization of preoperative computed tomographic imaging as an augmented display during robot-assisted laparoscopic partial nephrectomy. Stereoscopic video segments of a patient undergoing robot-assisted laparoscopic partial nephrectomy for tumor and another for a partial staghorn renal calculus were processed to evaluate the performance of a three-dimensional (3D)-to-3D registration algorithm. After both cases, we registered a segment of the video recording to the corresponding preoperative 3D-computed tomography image. After calibrating the camera and overlay, 3D-to-3D registration was created between the model and the surgical recording using a modified iterative closest point technique. Image-based tracking technology tracked selected fixed points on the kidney surface to augment the image-to-model registration. Our investigation has demonstrated that we can identify and track the kidney surface in real time when applied to intraoperative video recordings and overlay the 3D models of the kidney, tumor (or stone), and collecting system semitransparently. Using a basic computer research platform, we achieved an update rate of 10 Hz and an overlay latency of 4 frames. The accuracy of the 3D registration was 1 mm. Augmented reality overlay of reconstructed 3D-computed tomography images onto real-time stereo video footage is possible using iterative closest point and image-based surface tracking technology that does not use external navigation tracking systems or preplaced surface markers. Additional studies are needed to assess the precision and to achieve fully automated registration and display for intraoperative use.

Differences in Optical Coherence Tomography Assessment of Bruch Membrane Opening Compared to Stereoscopic Photography for Estimating Cup-to-Disc Ratio.

Science.gov (United States)

Mwanza, Jean-Claude; Huang, Linda Y; Budenz, Donald L; Shi, Wei; Huang, Gintien; Lee, Richard K

2017-12-01

To compare the vertical and horizontal cup-to-disc ratio (VCDR, HCDR) by an updated optical coherence tomography (OCT) Bruch membrane opening (BMO) algorithm and stereoscopic optic disc photograph readings by glaucoma specialists. Reliability analysis. A total of 195 eyes (116 glaucoma and 79 glaucoma suspect) of 99 patients with stereoscopic photographs and OCT scans of the optic discs taken during the same visit were compared. Optic disc photographs were read by 2 masked glaucoma specialists for VCDR and HCDR estimation. Intraclass correlation coefficient (ICC) and Bland-Altman plots were used to assess the agreement between photograph reading and OCT in estimating CDR. OCT images computed significantly larger VCDR and HCDR than photograph reading before and after stratifying eyes based on disc size (P < .001). The difference in CDR estimates between the 2 methods was equal to or greater than 0.2 in 29% and 35% of the eyes for VCDR and HCDR, respectively, with a mean difference of 0.3 in each case. The ICCs between the readers and OCT ranged between 0.50 and 0.63. The size of disagreement in VCDR correlated weakly with cup area in eyes with medium (r 2  = 0.10, P = .008) and large (r 2  = 0.09, P = .007) discs. OCT and photograph reading by clinicians agree poorly in CDR assessment. The difference in VCDR between the 2 methods was depended on cup area in medium and large discs. These differences should be considered when making conclusions regarding CDRs in clinical practice. Copyright © 2017 Elsevier Inc. All rights reserved.

Full-reference quality assessment of stereoscopic images by learning binocular receptive field properties.

Science.gov (United States)

Shao, Feng; Li, Kemeng; Lin, Weisi; Jiang, Gangyi; Yu, Mei; Dai, Qionghai

2015-10-01

Quality assessment of 3D images encounters more challenges than its 2D counterparts. Directly applying 2D image quality metrics is not the solution. In this paper, we propose a new full-reference quality assessment for stereoscopic images by learning binocular receptive field properties to be more in line with human visual perception. To be more specific, in the training phase, we learn a multiscale dictionary from the training database, so that the latent structure of images can be represented as a set of basis vectors. In the quality estimation phase, we compute sparse feature similarity index based on the estimated sparse coefficient vectors by considering their phase difference and amplitude difference, and compute global luminance similarity index by considering luminance changes. The final quality score is obtained by incorporating binocular combination based on sparse energy and sparse complexity. Experimental results on five public 3D image quality assessment databases demonstrate that in comparison with the most related existing methods, the devised algorithm achieves high consistency with subjective assessment.

Stereoscopic particle image velocimetry investigations of the mixed convection exchange flow through a horizontal vent

Science.gov (United States)

Varrall, Kevin; Pretrel, Hugues; Vaux, Samuel; Vauquelin, Olivier

2017-10-01

The exchange flow through a horizontal vent linking two compartments (one above the other) is studied experimentally. This exchange is here governed by both the buoyant natural effect due to the temperature difference of the fluids in both compartments, and the effect of a (forced) mechanical ventilation applied in the lower compartment. Such a configuration leads to uni- or bi-directional flows through the vent. In the experiments, buoyancy is induced in the lower compartment thanks to an electrical resistor. The forced ventilation is applied in exhaust or supply modes and three different values of the vent area. To estimate both velocity fields and flow rates at the vent, measurements are realized at thermal steady state, flush the vent in the upper compartment using stereoscopic particle image velocimetry (SPIV), which is original for this kind of flow. The SPIV measurements allows the area occupied by both upward and downward flows to be determined.

Parts-based stereoscopic image assessment by learning binocular manifold color visual properties

Science.gov (United States)

Xu, Haiyong; Yu, Mei; Luo, Ting; Zhang, Yun; Jiang, Gangyi

2016-11-01

Existing stereoscopic image quality assessment (SIQA) methods are mostly based on the luminance information, in which color information is not sufficiently considered. Actually, color is part of the important factors that affect human visual perception, and nonnegative matrix factorization (NMF) and manifold learning are in line with human visual perception. We propose an SIQA method based on learning binocular manifold color visual properties. To be more specific, in the training phase, a feature detector is created based on NMF with manifold regularization by considering color information, which not only allows parts-based manifold representation of an image, but also manifests localized color visual properties. In the quality estimation phase, visually important regions are selected by considering different human visual attention, and feature vectors are extracted by using the feature detector. Then the feature similarity index is calculated and the parts-based manifold color feature energy (PMCFE) for each view is defined based on the color feature vectors. The final quality score is obtained by considering a binocular combination based on PMCFE. The experimental results on LIVE I and LIVE Π 3-D IQA databases demonstrate that the proposed method can achieve much higher consistency with subjective evaluations than the state-of-the-art SIQA methods.

Stereoscopic filming for investigating evasive side-stepping and anterior cruciate ligament injury risk

Science.gov (United States)

Lee, Marcus J. C.; Bourke, Paul; Alderson, Jacqueline A.; Lloyd, David G.; Lay, Brendan

2010-02-01

Non-contact anterior cruciate ligament (ACL) injuries are serious and debilitating, often resulting from the performance of evasive sides-stepping (Ssg) by team sport athletes. Previous laboratory based investigations of evasive Ssg have used generic visual stimuli to simulate realistic time and space constraints that athletes experience in the preparation and execution of the manoeuvre. However, the use of unrealistic visual stimuli to impose these constraints may not be accurately identifying the relationship between the perceptual demands and ACL loading during Ssg in actual game environments. We propose that stereoscopically filmed footage featuring sport specific opposing defender/s simulating a tackle on the viewer, when used as visual stimuli, could improve the ecological validity of laboratory based investigations of evasive Ssg. Due to the need for precision and not just the experience of viewing depth in these scenarios, a rigorous filming process built on key geometric considerations and equipment development to enable a separation of 6.5 cm between two commodity cameras had to be undertaken. Within safety limits, this could be an invaluable tool in enabling more accurate investigations of the associations between evasive Ssg and ACL injury risk.

Stereoscopic motion analysis in densely packed clusters: 3D analysis of the shimmering behaviour in Giant honey bees.

Science.gov (United States)

Kastberger, Gerald; Maurer, Michael; Weihmann, Frank; Ruether, Matthias; Hoetzl, Thomas; Kranner, Ilse; Bischof, Horst

2011-02-08

The detailed interpretation of mass phenomena such as human escape panic or swarm behaviour in birds, fish and insects requires detailed analysis of the 3D movements of individual participants. Here, we describe the adaptation of a 3D stereoscopic imaging method to measure the positional coordinates of individual agents in densely packed clusters. The method was applied to study behavioural aspects of shimmering in Giant honeybees, a collective defence behaviour that deters predatory wasps by visual cues, whereby individual bees flip their abdomen upwards in a split second, producing Mexican wave-like patterns. Stereoscopic imaging provided non-invasive, automated, simultaneous, in-situ 3D measurements of hundreds of bees on the nest surface regarding their thoracic position and orientation of the body length axis. Segmentation was the basis for the stereo matching, which defined correspondences of individual bees in pairs of stereo images. Stereo-matched "agent bees" were re-identified in subsequent frames by the tracking procedure and triangulated into real-world coordinates. These algorithms were required to calculate the three spatial motion components (dx: horizontal, dy: vertical and dz: towards and from the comb) of individual bees over time. The method enables the assessment of the 3D positions of individual Giant honeybees, which is not possible with single-view cameras. The method can be applied to distinguish at the individual bee level active movements of the thoraces produced by abdominal flipping from passive motions generated by the moving bee curtain. The data provide evidence that the z-deflections of thoraces are potential cues for colony-intrinsic communication. The method helps to understand the phenomenon of collective decision-making through mechanoceptive synchronization and to associate shimmering with the principles of wave propagation. With further, minor modifications, the method could be used to study aspects of other mass phenomena that

Stereoscopic motion analysis in densely packed clusters: 3D analysis of the shimmering behaviour in Giant honey bees

Directory of Open Access Journals (Sweden)

Hoetzl Thomas

2011-02-01

Full Text Available Abstract Background The detailed interpretation of mass phenomena such as human escape panic or swarm behaviour in birds, fish and insects requires detailed analysis of the 3D movements of individual participants. Here, we describe the adaptation of a 3D stereoscopic imaging method to measure the positional coordinates of individual agents in densely packed clusters. The method was applied to study behavioural aspects of shimmering in Giant honeybees, a collective defence behaviour that deters predatory wasps by visual cues, whereby individual bees flip their abdomen upwards in a split second, producing Mexican wave-like patterns. Results Stereoscopic imaging provided non-invasive, automated, simultaneous, in-situ 3D measurements of hundreds of bees on the nest surface regarding their thoracic position and orientation of the body length axis. Segmentation was the basis for the stereo matching, which defined correspondences of individual bees in pairs of stereo images. Stereo-matched "agent bees" were re-identified in subsequent frames by the tracking procedure and triangulated into real-world coordinates. These algorithms were required to calculate the three spatial motion components (dx: horizontal, dy: vertical and dz: towards and from the comb of individual bees over time. Conclusions The method enables the assessment of the 3D positions of individual Giant honeybees, which is not possible with single-view cameras. The method can be applied to distinguish at the individual bee level active movements of the thoraces produced by abdominal flipping from passive motions generated by the moving bee curtain. The data provide evidence that the z-deflections of thoraces are potential cues for colony-intrinsic communication. The method helps to understand the phenomenon of collective decision-making through mechanoceptive synchronization and to associate shimmering with the principles of wave propagation. With further, minor modifications, the method

Time Dependence of Intrafraction Patient Motion Assessed by Repeat Stereoscopic Imaging

International Nuclear Information System (INIS)

Hoogeman, Mischa S.; Nuyttens, Joost J.; Levendag, Peter C.; Heijmen, Ben J.M.

2008-01-01

Purpose: To quantify intrafraction patient motion and its time dependence in immobilized intracranial and extracranial patients. The data can be used to optimize the intrafraction imaging frequency and consequent patient setup correction with an image guidance and tracking system, and to establish the required safety margins in the absence of such a system. Method and Materials: The intrafraction motion of 32 intracranial patients, immobilized with a thermoplastic mask, and 11 supine- and 14 prone-treated extracranial spine patients, immobilized with a vacuum bag, were analyzed. The motion was recorded by an X-ray, stereoscopic, image-guidance system. For each group, we calculated separately the systematic (overall mean and SD) and the random displacement as a function of elapsed intrafraction time. Results: The SD of the systematic intrafraction displacements increased linearly over time for all three patient groups. For intracranial-, supine-, and prone-treated patients, the SD increased to 0.8, 1.2, and 2.2 mm, respectively, in a period of 15 min. The random displacements for the prone-treated patients were significantly higher than for the other groups, namely 1.6 mm (1 SD), probably caused by respiratory motion. Conclusions: Despite the applied immobilization devices, patients drift away from their initial position during a treatment fraction. These drifts are in general small if compared with conventional treatment margins, but will significantly contribute to the margin for high-precision radiation treatments with treatment times of 15 min or longer

Turbulent Structure of a Simplified Urban Fluid Flow Studied Through Stereoscopic Particle Image Velocimetry

Science.gov (United States)

Monnier, Bruno; Goudarzi, Sepehr A.; Vinuesa, Ricardo; Wark, Candace

2018-02-01

Stereoscopic particle image velocimetry was used to provide a three-dimensional characterization of the flow around a simplified urban model defined by a 5 by 7 array of blocks, forming four parallel streets, perpendicular to the incoming wind direction corresponding to a zero angle of incidence. Channeling of the flow through the array under consideration was observed, and its effect increased as the incoming wind direction, or angle of incidence ( AOI), was changed from 0° to 15°, 30°, and 45°. The flow between blocks can be divided into two regions: a region of low turbulence kinetic energy (TKE) levels close to the leeward side of the upstream block, and a high TKE area close to the downstream block. The centre of the arch vortex is located in the low TKE area, and two regions of large streamwise velocity fluctuation bound the vortex in the spanwise direction. Moreover, a region of large spanwise velocity fluctuation on the downstream block is found between the vortex legs. Our results indicate that the reorientation of the arch vortex at increasing AOI is produced by the displacement of the different TKE regions and their interaction with the shear layers on the sides and top of the upstream and downstream blocks, respectively. There is also a close connection between the turbulent structure between the blocks and the wind gusts. The correlations among gust components were also studied, and it was found that in the near-wall region of the street the correlations between the streamwise and spanwise gusts R_{uv} were dominant for all four AOI cases. At higher wall-normal positions in the array, the R_{uw} correlation decreased with increasing AOI, whereas the R_{uv} coefficient increased as AOI increased, and at {it{AOI}}=45° all three correlations exhibited relatively high values of around 0.4.

Explorable three-dimensional digital model of the female pelvis, pelvic contents, and perineum for anatomical education.

Science.gov (United States)

Sergovich, Aimée; Johnson, Marjorie; Wilson, Timothy D

2010-01-01

The anatomy of the pelvis is complex, multilayered, and its three-dimensional organization is conceptually difficult for students to grasp. The aim of this project was to create an explorable and projectable stereoscopic, three-dimensional (3D) model of the female pelvis and pelvic contents for anatomical education. The model was created using cryosection images obtained from the Visible Human Project, in conjunction with a general-purpose three-dimensional segmentation and surface-rendering program. Anatomical areas of interest were identified and labeled on consecutive images. Each 2D slice was reassembled, forming a three-dimensional model. The model includes the pelvic girdle, organs of the pelvic cavity, surrounding musculature, the perineum, neurovascular structures, and the peritoneum. Each structure can be controlled separately (e.g. added, subtracted, made transparent) to reveal organization and/or relationships between structures. The model can be manipulated and/or projected stereoscopically to visualize structures and relationships from different angles with excellent spatial perception. Because of its ease of use and versatility, we expect this model may provide a powerful teaching tool for learning in the classroom or in the laboratory. (c) 2010 American Association of Anatomists.

Three-dimensional temporally resolved measurements of turbulence-flame interactions using orthogonal-plane cinema-stereoscopic PIV

Energy Technology Data Exchange (ETDEWEB)

Steinberg, Adam Michael; Driscoll, James F. [University of Michigan, Department of Aerospace Engineering, Ann Arbor, MI (United States); Ceccio, Steven L. [University of Michigan, Department of Mechanical Engineering, Ann Arbor, MI (United States)

2009-09-15

A new orthogonal-plane cinema-stereoscopic particle image velocimetry (OPCS-PIV) diagnostic has been used to measure the dynamics of three-dimensional turbulence-flame interactions. The diagnostic employed two orthogonal PIV planes, with one aligned perpendicular and one aligned parallel to the streamwise flow direction. In the plane normal to the flow, temporally resolved slices of the nine-component velocity gradient tensor were determined using Taylor's hypothesis. Volumetric reconstruction of the 3D turbulence was performed using these slices. The PIV plane parallel to the streamwise flow direction was then used to measure the evolution of the turbulence; the path and strength of 3D turbulent structures as they interacted with the flame were determined from their image in this second plane. Structures of both vorticity and strain-rate magnitude were extracted from the flow. The geometry of these structures agreed well with predictions from direct numerical simulations. The interaction of turbulent structures with the flame also was observed. In three dimensions, these interactions had complex geometries that could not be reflected in either planar measurements or simple flame-vortex configurations. (orig.)

Analysis of the three-dimensional trajectories of dusts observed with a stereoscopic fast framing camera in the Large Helical Device

Energy Technology Data Exchange (ETDEWEB)

Shoji, M., E-mail: shoji@LHD.nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Gifu (Japan); Masuzaki, S. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Gifu (Japan); Tanaka, Y. [Kanazawa University, Kakuma, Kanazawa 920-1192 (Japan); Pigarov, A.Yu.; Smirnov, R.D. [University of California at San Diego, La Jolla, CA 92093 (United States); Kawamura, G.; Uesugi, Y.; Yamada, H. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Gifu (Japan)

2015-08-15

The three-dimensional trajectories of dusts have been observed with two stereoscopic fast framing cameras installed in upper and outer viewports in the Large Helical Device (LHD). It shows that the dust trajectories locate in divertor legs and an ergodic layer around the main plasma confinement region. While it is found that most of the dusts approximately move along the magnetic field lines with acceleration, there are some dusts which have sharply curved trajectories crossing over the magnetic field lines. A dust transport simulation code was modified to investigate the dust trajectories in fully three dimensional geometries such as LHD plasmas. It can explain the general trend of most of observed dust trajectories by the effect of the plasma flow in the peripheral plasma. However, the behavior of the some dusts with sharply curved trajectories is not consistent with the simulations.

Stereoscopic displays for virtual reality in the car manufacturing industry: application to design review and ergonomic studies

Science.gov (United States)

Moreau, Guillaume; Fuchs, Philippe

2002-05-01

In the car manufacturing industry the trend is to drastically reduce the time-to-market by increasing the use of the Digital Mock-up instead of physical prototypes. Design review and ergonomic studies are specific tasks because they involve qualitative or even subjective judgements. In this paper, we present IMAVE (IMmersion Adapted to a VEhicle) designed for immersive styling review, gaps visualization and simple ergonomic studies. We show that stereoscopic displays are necessary and must fulfill several constraints due to the proximity and size of the car dashboard. The duration fo the work sessions forces us to eliminate all vertical parallax, and 1:1 scale is obviously required for a valid immersion. Two demonstrators were realized allowing us to have a large set of testers (over 100). More than 80% of the testers saw an immediate use of the IMAVE system. We discuss the good and bad marks awarded to the system. Future work include being able to use several rear-projected stereo screens for doors and central console visualization, but without the parallax presently visible in some CAVE-like environments.

Volume Attenuation and High Frequency Loss as Auditory Depth Cues in Stereoscopic 3D Cinema

Science.gov (United States)

Manolas, Christos; Pauletto, Sandra

2014-09-01

Assisted by the technological advances of the past decades, stereoscopic 3D (S3D) cinema is currently in the process of being established as a mainstream form of entertainment. The main focus of this collaborative effort is placed on the creation of immersive S3D visuals. However, with few exceptions, little attention has been given so far to the potential effect of the soundtrack on such environments. The potential of sound both as a means to enhance the impact of the S3D visual information and to expand the S3D cinematic world beyond the boundaries of the visuals is large. This article reports on our research into the possibilities of using auditory depth cues within the soundtrack as a means of affecting the perception of depth within cinematic S3D scenes. We study two main distance-related auditory cues: high-end frequency loss and overall volume attenuation. A series of experiments explored the effectiveness of these auditory cues. Results, although not conclusive, indicate that the studied auditory cues can influence the audience judgement of depth in cinematic 3D scenes, sometimes in unexpected ways. We conclude that 3D filmmaking can benefit from further studies on the effectiveness of specific sound design techniques to enhance S3D cinema.

Influence of outlet geometry on the swirling flow in a simplfied model of a large two-stroke marine diesel engine

DEFF Research Database (Denmark)

Haider, Sajjad; Schnipper, Teis; Meyer, Knud Erik

We present Stereoscopic particle image velocimetry measurements of the effect of a dummy-valve on the in-cylinder swirling flow in a simplified scale model of a large two-stroke marine diesel engine cylinder using air at room temperature and pressure as the working fluid and Reynolds number 19500...

Project NANO (nanoscience and nanotechnology outreach): a STEM training program that brings SEM's and stereoscopes into high-school and middle-school classrooms

Science.gov (United States)

Cady, Sherry L.; Blok, Mikel; Grosse, Keith; Wells, Jennifer

2014-09-01

The program Project NANO (Nanoscience and Nanotechnology Outreach) enables middle and high school students to discover and research submicroscopic phenomena in a new and exciting way with the use of optical and scanning electron microscopes in the familiar surroundings of their middle or high school classrooms. Project NANO provides secondary level professional development workshops, support for classroom instruction and teacher curriculum development, and the means to deliver Project NANO toolkits (SEM, stereoscope, computer, supplies) to classrooms with Project NANO trained teachers. Evaluation surveys document the impact of the program on student's attitudes toward science and technology and on the learning outcomes for secondary level teachers. Project NANO workshops (offered for professional development credit) enable teachers to gain familiarity using and teaching with the SEM. Teachers also learn to integrate new content knowledge and skills into topic-driven, standards-based units of instruction specifically designed to support the development of students' higher order thinking skills that include problem solving and evidence-based thinking. The Project NANO management team includes a former university science faculty, two high school science teachers, and an educational researcher. To date, over 7500 students have experienced the impact of the Project NANO program, which provides an exciting and effective model for engaging students in the discovery of nanoscale phenomena and concepts in a fun and engaging way.

Holistic processing for bodies and body parts: New evidence from stereoscopic depth manipulations.

Science.gov (United States)

Harris, Alison; Vyas, Daivik B; Reed, Catherine L

2016-10-01

Although holistic processing has been documented extensively for upright faces, it is unclear whether it occurs for other visual categories with more extensive substructure, such as body postures. Like faces, body postures have high social relevance, but they differ in having fine-grain organization not only of basic parts (e.g., arm) but also subparts (e.g., elbow, wrist, hand). To compare holistic processing for whole bodies and body parts, we employed a novel stereoscopic depth manipulation that creates either the percept of a whole body occluded by a set of bars, or of segments of a body floating in front of a background. Despite sharing low-level visual properties, only the stimulus perceived as being behind bars should be holistically "filled in" via amodal completion. In two experiments, we tested for better identification of individual body parts within the context of a body versus in isolation. Consistent with previous findings, recognition of body parts was better in the context of a whole body when the body was amodally completed behind occluders. However, when the same bodies were perceived as floating in strips, performance was significantly worse, and not significantly different, from that for amodally completed parts, supporting holistic processing of body postures. Intriguingly, performance was worst for parts in the frontal depth condition, suggesting that these effects may extend from gross body organization to a more local level. These results provide suggestive evidence that holistic representations may not be "all-or-none," but rather also operate on body regions of more limited spatial extent.

A comparative study of manhole hydraulics using stereoscopic PIV and different RANS models.

Science.gov (United States)

Beg, Md Nazmul Azim; Carvalho, Rita F; Tait, Simon; Brevis, Wernher; Rubinato, Matteo; Schellart, Alma; Leandro, Jorge

2017-04-01

Flows in manholes are complex and may include swirling and recirculation flow with significant turbulence and vorticity. However, how these complex 3D flow patterns could generate different energy losses and so affect flow quantity in the wider sewer network is unknown. In this work, 2D3C stereo Particle Image Velocimetry measurements are made in a surcharged scaled circular manhole. A computational fluid dynamics (CFD) model in OpenFOAM ® with four different Reynolds Averaged Navier Stokes (RANS) turbulence model is constructed using a volume of fluid model, to represent flows in this manhole. Velocity profiles and pressure distributions from the models are compared with the experimental data in view of finding the best modelling approach. It was found among four different RANS models that the re-normalization group (RNG) k-ɛ and k-ω shear stress transport (SST) gave a better approximation for velocity and pressure.

Turbulent swirling flow in a dynamic model of a uniflow-scavenged two-stroke engine

DEFF Research Database (Denmark)

Ingvorsen, Kristian Mark; Meyer, Knud Erik; Walther, Jens Honore

2014-01-01

turbulence models. In the present work, the flow in a dynamic scale model of a uniflowscavenged cylinder is investigated experimentally. The model has a transparent cylinder and a moving piston driven by a linear motor. The flow is investigated using phase-locked stereoscopic particle image velocimetry (PIV...... cannot be assumed to be quasi-steady. The temporal development of the swirl strength is investigated by computing the angular momentum. The swirl strength shows an exponential decay from scavenge port closing to scavenge port opening corresponding to a reduction of 34 %, which is in good agreement...

PIV in a model wind turbine rotor wake

DEFF Research Database (Denmark)

Meyer, Knud Erik; Naumov, Igor; Karbadin, Ivan

2013-01-01

Stereoscopic particle image velocimetry (PIV) measurements of the flow in the wake of scale model of a horizontal axis wind turbine is presented Near the rotor, measurements are made in vertical planes intersecting the rotor axis These planes capture flow effect from the tip and root vortices...... perpendicular to the rotor axis is used to investigate the dynamics in the far wake Here, a precessing core is found and data indicate that the Strouhal number of the precessing is independent of the rotor speed...

Modeling of a 3DTV service in the software-defined networking architecture

Science.gov (United States)

Wilczewski, Grzegorz

2014-11-01

In this article a newly developed concept towards modeling of a multimedia service offering stereoscopic motion imagery is presented. Proposed model is based on the approach of utilization of Software-defined Networking or Software Defined Networks architecture (SDN). The definition of 3D television service spanning SDN concept is identified, exposing basic characteristic of a 3DTV service in a modern networking organization layout. Furthermore, exemplary functionalities of the proposed 3DTV model are depicted. It is indicated that modeling of a 3DTV service in the Software-defined Networking architecture leads to multiplicity of improvements, especially towards flexibility of a service supporting heterogeneity of end user devices.

Calibration grooming and alignment for LDUA High Resolution Stereoscopic Video Camera System (HRSVS)

International Nuclear Information System (INIS)

Pardini, A.F.

1998-01-01

The High Resolution Stereoscopic Video Camera System (HRSVS) was designed by the Savannah River Technology Center (SRTC) to provide routine and troubleshooting views of tank interiors during characterization and remediation phases of underground storage tank (UST) processing. The HRSVS is a dual color camera system designed to provide stereo viewing of the interior of the tanks including the tank wall in a Class 1, Division 1, flammable atmosphere. The HRSVS was designed with a modular philosophy for easy maintenance and configuration modifications. During operation of the system with the LDUA, the control of the camera system will be performed by the LDUA supervisory data acquisition system (SDAS). Video and control status 1458 will be displayed on monitors within the LDUA control center. All control functions are accessible from the front panel of the control box located within the Operations Control Trailer (OCT). The LDUA will provide all positioning functions within the waste tank for the end effector. Various electronic measurement instruments will be used to perform CG and A activities. The instruments may include a digital volt meter, oscilloscope, signal generator, and other electronic repair equipment. None of these instruments will need to be calibrated beyond what comes from the manufacturer. During CG and A a temperature indicating device will be used to measure the temperature of the outside of the HRSVS from initial startup until the temperature has stabilized. This device will not need to be in calibration during CG and A but will have to have a current calibration sticker from the Standards Laboratory during any acceptance testing. This sensor will not need to be in calibration during CG and A but will have to have a current calibration sticker from the Standards Laboratory during any acceptance testing

Stereoscopic-3D display design: a new paradigm with Intel Adaptive Stable Image Technology [IA-SIT

Science.gov (United States)

Jain, Sunil

2012-03-01

Stereoscopic-3D (S3D) proliferation on personal computers (PC) is mired by several technical and business challenges: a) viewing discomfort due to cross-talk amongst stereo images; b) high system cost; and c) restricted content availability. Users expect S3D visual quality to be better than, or at least equal to, what they are used to enjoying on 2D in terms of resolution, pixel density, color, and interactivity. Intel Adaptive Stable Image Technology (IA-SIT) is a foundational technology, successfully developed to resolve S3D system design challenges and deliver high quality 3D visualization at PC price points. Optimizations in display driver, panel timing firmware, backlight hardware, eyewear optical stack, and synch mechanism combined can help accomplish this goal. Agnostic to refresh rate, IA-SIT will scale with shrinking of display transistors and improvements in liquid crystal and LED materials. Industry could profusely benefit from the following calls to action:- 1) Adopt 'IA-SIT S3D Mode' in panel specs (via VESA) to help panel makers monetize S3D; 2) Adopt 'IA-SIT Eyewear Universal Optical Stack' and algorithm (via CEA) to help PC peripheral makers develop stylish glasses; 3) Adopt 'IA-SIT Real Time Profile' for sub-100uS latency control (via BT Sig) to extend BT into S3D; and 4) Adopt 'IA-SIT Architecture' for Monitors and TVs to monetize via PC attach.

Cortical dynamics of figure-ground separation in response to 2D pictures and 3D scenes:How V2 combines border ownership, stereoscopic cues, and Gestalt grouping rules

Directory of Open Access Journals (Sweden)

Stephen eGrossberg

2016-01-01

Full Text Available The FACADE model, and its laminar cortical realization and extension in the 3D LAMINART model, have explained, simulated, and predicted many perceptual and neurobiological data about how the visual cortex carries out 3D vision and figure-ground perception, and how these cortical mechanisms enable 2D pictures to generate 3D percepts of occluding and occluded objects. In particular, these models have proposed how border ownership occurs, but have not yet explicitly explained the correlation between multiple properties of border ownership neurons in cortical area V2 that were reported in a remarkable series of neurophysiological experiments by von der Heydt and his colleagues; namely, border ownership, contrast preference, binocular stereoscopic information, selectivity for side-of-figure, Gestalt rules, and strength of attentional modulation, as well as the time course during which such properties arise. This article shows how, by combining 3D LAMINART properties that were discovered in two parallel streams of research, a unified explanation of these properties emerges. This explanation proposes, moreover, how these properties contribute to the generation of consciously seen 3D surfaces. The first research stream models how processes like 3D boundary grouping and surface filling-in interact in multiple stages within and between the V1 interblob – V2 interstripe – V4 cortical stream and the V1 blob – V2 thin stripe – V4 cortical stream, respectively. Of particular importance for understanding figure-ground separation is how these cortical interactions convert computationally complementary boundary and surface mechanisms into a consistent conscious percept, including the critical use of surface contour feedback signals from surface representations in V2 thin stripes to boundary representations in V2 interstripes. Remarkably, key figure-ground properties emerge from these feedback interactions. The second research stream shows how cells that

Potential hazards of viewing 3-D stereoscopic television, cinema and computer games: a review.

Science.gov (United States)

Howarth, Peter A

2011-03-01

The visual stimulus provided by a 3-D stereoscopic display differs from that of the real world because the image provided to each eye is produced on a flat surface. The distance from the screen to the eye remains fixed, providing a single focal distance, but the introduction of disparity between the images allows objects to be located geometrically in front of, or behind, the screen. Unlike in the real world, the stimulus to accommodation and the stimulus to convergence do not match. Although this mismatch is used positively in some forms of Orthoptic treatment, a number of authors have suggested that it could negatively lead to the development of asthenopic symptoms. From knowledge of the zone of clear, comfortable, single binocular vision one can predict that, for people with normal binocular vision, adverse symptoms will not be present if the discrepancy is small, but are likely if it is large, and that what constitutes 'large' and 'small' are idiosyncratic to the individual. The accommodation-convergence mismatch is not, however, the only difference between the natural and the artificial stimuli. In the former case, an object located in front of, or behind, a fixated object will not only be perceived as double if the images fall outside Panum's fusional areas, but it will also be defocused and blurred. In the latter case, however, it is usual for the producers of cinema, TV or computer game content to provide an image that is in focus over the whole of the display, and as a consequence diplopic images will be sharply in focus. The size of Panum's fusional area is spatial frequency-dependent, and because of this the high spatial frequencies present in the diplopic 3-D image will provide a different stimulus to the fusion system from that found naturally. © 2011 The College of Optometrists.

Extended two-photon microscopy in live samples with Bessel beams: steadier focus, faster volume scans, and simpler stereoscopic imaging.

Science.gov (United States)

Thériault, Gabrielle; Cottet, Martin; Castonguay, Annie; McCarthy, Nathalie; De Koninck, Yves

2014-01-01

Two-photon microscopy has revolutionized functional cellular imaging in tissue, but although the highly confined depth of field (DOF) of standard set-ups yields great optical sectioning, it also limits imaging speed in volume samples and ease of use. For this reason, we recently presented a simple and retrofittable modification to the two-photon laser-scanning microscope which extends the DOF through the use of an axicon (conical lens). Here we demonstrate three significant benefits of this technique using biological samples commonly employed in the field of neuroscience. First, we use a sample of neurons grown in culture and move it along the z-axis, showing that a more stable focus is achieved without compromise on transverse resolution. Second, we monitor 3D population dynamics in an acute slice of live mouse cortex, demonstrating that faster volumetric scans can be conducted. Third, we acquire a stereoscopic image of neurons and their dendrites in a fixed sample of mouse cortex, using only two scans instead of the complete stack and calculations required by standard systems. Taken together, these advantages, combined with the ease of integration into pre-existing systems, make the extended depth-of-field imaging based on Bessel beams a strong asset for the field of microscopy and life sciences in general.

A pilot study on pupillary and cardiovascular changes induced by stereoscopic video movies

Directory of Open Access Journals (Sweden)

Sugita Norihiro

2007-10-01

Full Text Available Abstract Background Taking advantage of developed image technology, it is expected that image presentation would be utilized to promote health in the field of medical care and public health. To accumulate knowledge on biomedical effects induced by image presentation, an essential prerequisite for these purposes, studies on autonomic responses in more than one physiological system would be necessary. In this study, changes in parameters of the pupillary light reflex and cardiovascular reflex evoked by motion pictures were examined, which would be utilized to evaluate the effects of images, and to avoid side effects. Methods Three stereoscopic video movies with different properties were field-sequentially rear-projected through two LCD projectors on an 80-inch screen. Seven healthy young subjects watched movies in a dark room. Pupillary parameters were measured before and after presentation of movies by an infrared pupillometer. ECG and radial blood pressure were continuously monitored. The maximum cross-correlation coefficient between heart rate and blood pressure, ρmax, was used as an index to evaluate changes in the cardiovascular reflex. Results Parameters of pupillary and cardiovascular reflexes changed differently after subjects watched three different video movies. Amplitudes of the pupillary light reflex, CR, increased when subjects watched two CG movies (movies A and D, while they did not change after watching a movie with the real scenery (movie R. The ρmax was significantly larger after presentation of the movie D. Scores of the questionnaire for subjective evaluation of physical condition increased after presentation of all movies, but their relationship with changes in CR and ρmax was different in three movies. Possible causes of these biomedical differences are discussed. Conclusion The autonomic responses were effective to monitor biomedical effects induced by image presentation. Further accumulation of data on multiple autonomic

Stereoscopy in Astronomical Visualizations to Support Learning at Informal Education Settings

Science.gov (United States)

Price, Aaron; Lee, Hee-Sun

2015-08-01

Stereoscopy has been used in science education for 100 years. Recent innovations in low cost technology as well as trends in the entertainment industry have made stereoscopy popular among educators and audiences alike. However, experimental studies addressing whether stereoscopy actually impacts science learning are limited. Over the last decade, we have conducted a series of quasi-experimental and experimental studies on how children and adult visitors in science museums and planetariums learned about the structure and function of highly spatial scientific objects such as galaxies, supernova, etc. We present a synthesis of the results from these studies and implications for stereoscopic visualization development. The overall finding is that the impact of stereoscopy on perceptions of scientific objects is limited when presented as static imagery. However, when presented as full motion films, a significantly positive impact was detected. To conclude, we present a set of stereoscopic design principles that can help design astronomical stereoscopic films that support deep and effective learning. Our studies cover astronomical content such as the engineering of and imagery from the Mars rovers, artistic stereoscopic imagery of nebulae and a high-resolution stereoscopic film about how astronomers measure and model the structure of our galaxy.

Partially converted stereoscopic images and the effects on visual attention and memory

Science.gov (United States)

Kim, Sanghyun; Morikawa, Hiroyuki; Mitsuya, Reiko; Kawai, Takashi; Watanabe, Katsumi

2015-03-01

This study contained two experimental examinations of the cognitive activities such as visual attention and memory in viewing stereoscopic (3D) images. For this study, partially converted 3D images were used with binocular parallax added to a specific region of the image. In Experiment 1, change blindness was used as a presented stimulus. The visual attention and impact on memory were investigated by measuring the response time to accomplish the given task. In the change blindness task, an 80 ms blank was intersected between the original and altered images, and the two images were presented alternatingly for 240 ms each. Subjects were asked to temporarily memorize the two switching images and to compare them, visually recognizing the difference between the two. The stimuli for four conditions (2D, 3D, Partially converted 3D, distracted partially converted 3D) were randomly displayed for 20 subjects. The results of Experiment 1 showed that partially converted 3D images tend to attract visual attention and are prone to remain in viewer's memory in the area where moderate negative parallax has been added. In order to examine the impact of a dynamic binocular disparity on partially converted 3D images, an evaluation experiment was conducted that applied learning, distraction, and recognition tasks for 33 subjects. The learning task involved memorizing the location of cells in a 5 × 5 matrix pattern using two different colors. Two cells were positioned with alternating colors, and one of the gray cells was moved up, down, left, or right by one cell width. Experimental conditions was set as a partially converted 3D condition in which a gray cell moved diagonally for a certain period of time with a dynamic binocular disparity added, a 3D condition in which binocular disparity was added to all gray cells, and a 2D condition. The correct response rates for recognition of each task after the distraction task were compared. The results of Experiment 2 showed that the correct

Stereoscopy in cinematographic synthetic imagery

Science.gov (United States)

Eisenmann, Jonathan; Parent, Rick

2009-02-01

In this paper we present experiments and results pertaining to the perception of depth in stereoscopic viewing of synthetic imagery. In computer animation, typical synthetic imagery is highly textured and uses stylized illumination of abstracted material models by abstracted light source models. While there have been numerous studies concerning stereoscopic capabilities, conventions for staging and cinematography in stereoscopic movies have not yet been well-established. Our long-term goal is to measure the effectiveness of various cinematography techniques on the human visual system in a theatrical viewing environment. We would like to identify the elements of stereoscopic cinema that are important in terms of enhancing the viewer's understanding of a scene as well as providing guidelines for the cinematographer relating to storytelling. In these experiments we isolated stereoscopic effects by eliminating as many other visual cues as is reasonable. In particular, we aim to empirically determine what types of movement in synthetic imagery affect the perceptual depth sensing capabilities of our viewers. Using synthetic imagery, we created several viewing scenarios in which the viewer is asked to locate a target object's depth in a simple environment. The scenarios were specifically designed to compare the effectiveness of stereo viewing, camera movement, and object motion in aiding depth perception. Data were collected showing the error between the choice of the user and the actual depth value, and patterns were identified that relate the test variables to the viewer's perceptual depth accuracy in our theatrical viewing environment.

Three Software Tools for Viewing Sectional Planes, Volume Models, and Surface Models of a Cadaver Hand.

Science.gov (United States)

Chung, Beom Sun; Chung, Min Suk; Shin, Byeong Seok; Kwon, Koojoo

2018-02-19

The hand anatomy, including the complicated hand muscles, can be grasped by using computer-assisted learning tools with high quality two-dimensional images and three-dimensional models. The purpose of this study was to present up-to-date software tools that promote learning of stereoscopic morphology of the hand. On the basis of horizontal sectioned images and outlined images of a male cadaver, vertical planes, volume models, and surface models were elaborated. Software to browse pairs of the sectioned and outlined images in orthogonal planes and software to peel and rotate the volume models, as well as a portable document format (PDF) file to select and rotate the surface models, were produced. All of the software tools were downloadable free of charge and usable off-line. The three types of tools for viewing multiple aspects of the hand could be adequately employed according to individual needs. These new tools involving the realistic images of a cadaver and the diverse functions are expected to improve comprehensive knowledge of the hand shape. © 2018 The Korean Academy of Medical Sciences.

PIV measurements of flow structures in a spray dryer

DEFF Research Database (Denmark)

Meyer, Knud Erik; Velte, Clara Marika; Ullum, Thorvald

2011-01-01

Stereoscopic Particle Image Velocimetry (PIV) measurements are made in horizontal planes in a simplified scale model of a spray dryer using water as fluid. The sample rate was sufficient to resolve phenomena at lower frequencies. Data reveal asymmetric velocity fields in both mean fields and dyna......Stereoscopic Particle Image Velocimetry (PIV) measurements are made in horizontal planes in a simplified scale model of a spray dryer using water as fluid. The sample rate was sufficient to resolve phenomena at lower frequencies. Data reveal asymmetric velocity fields in both mean fields...

Modeling of driver's collision avoidance maneuver based on controller switching model.

Science.gov (United States)

Kim, Jong-Hae; Hayakawa, Soichiro; Suzuki, Tatsuya; Hayashi, Koji; Okuma, Shigeru; Tsuchida, Nuio; Shimizu, Masayuki; Kido, Shigeyuki

2005-12-01

This paper presents a modeling strategy of human driving behavior based on the controller switching model focusing on the driver's collision avoidance maneuver. The driving data are collected by using the three-dimensional (3-D) driving simulator based on the CAVE Automatic Virtual Environment (CAVE), which provides stereoscopic immersive virtual environment. In our modeling, the control scenario of the human driver, that is, the mapping from the driver's sensory information to the operation of the driver such as acceleration, braking, and steering, is expressed by Piecewise Polynomial (PWP) model. Since the PWP model includes both continuous behaviors given by polynomials and discrete logical conditions, it can be regarded as a class of Hybrid Dynamical System (HDS). The identification problem for the PWP model is formulated as the Mixed Integer Linear Programming (MILP) by transforming the switching conditions into binary variables. From the obtained results, it is found that the driver appropriately switches the "control law" according to the sensory information. In addition, the driving characteristics of the beginner driver and the expert driver are compared and discussed. These results enable us to capture not only the physical meaning of the driving skill but the decision-making aspect (switching conditions) in the driver's collision avoidance maneuver as well.

Visual discomfort while watching stereoscopic three-dimensional movies at the cinema.

Science.gov (United States)

Zeri, Fabrizio; Livi, Stefano

2015-05-01

This study investigates discomfort symptoms while watching Stereoscopic three-dimensional (S3D) movies in the 'real' condition of a cinema. In particular, it had two main objectives: to evaluate the presence and nature of visual discomfort while watching S3D movies, and to compare visual symptoms during S3D and 2D viewing. Cinema spectators of S3D or 2D films were interviewed by questionnaire at the theatre exit of different multiplex cinemas immediately after viewing a movie. A total of 854 subjects were interviewed (mean age 23.7 ± 10.9 years; range 8-81 years; 392 females and 462 males). Five hundred and ninety-nine of them viewed different S3D movies, and 255 subjects viewed a 2D version of a film seen in S3D by 251 subjects from the S3D group for a between-subjects design for that comparison. Exploratory factor analysis revealed two factors underlying symptoms: External Symptoms Factors (ESF) with a mean ± S.D. symptom score of 1.51 ± 0.58 comprised of eye burning, eye ache, eye strain, eye irritation and tearing; and Internal Symptoms Factors (ISF) with a mean ± S.D. symptom score of 1.38 ± 0.51 comprised of blur, double vision, headache, dizziness and nausea. ISF and ESF were significantly correlated (Spearman r = 0.55; p = 0.001) but with external symptoms significantly higher than internal ones (Wilcoxon Signed-ranks test; p = 0.001). The age of participants did not significantly affect symptoms. However, females had higher scores than males for both ESF and ISF, and myopes had higher ISF scores than hyperopes. Newly released movies provided lower ESF scores than older movies, while the seat position of spectators had minimal effect. Symptoms while viewing S3D movies were significantly and negatively correlated to the duration of wearing S3D glasses. Kruskal-Wallis results showed that symptoms were significantly greater for S3D compared to those of 2D movies, both for ISF (p = 0.001) and for ESF (p = 0.001). In short, the analysis of the symptoms

Cortical Dynamics of Figure-Ground Separation in Response to 2D Pictures and 3D Scenes: How V2 Combines Border Ownership, Stereoscopic Cues, and Gestalt Grouping Rules

Science.gov (United States)

Grossberg, Stephen

2016-01-01

The FACADE model, and its laminar cortical realization and extension in the 3D LAMINART model, have explained, simulated, and predicted many perceptual and neurobiological data about how the visual cortex carries out 3D vision and figure-ground perception, and how these cortical mechanisms enable 2D pictures to generate 3D percepts of occluding and occluded objects. In particular, these models have proposed how border ownership occurs, but have not yet explicitly explained the correlation between multiple properties of border ownership neurons in cortical area V2 that were reported in a remarkable series of neurophysiological experiments by von der Heydt and his colleagues; namely, border ownership, contrast preference, binocular stereoscopic information, selectivity for side-of-figure, Gestalt rules, and strength of attentional modulation, as well as the time course during which such properties arise. This article shows how, by combining 3D LAMINART properties that were discovered in two parallel streams of research, a unified explanation of these properties emerges. This explanation proposes, moreover, how these properties contribute to the generation of consciously seen 3D surfaces. The first research stream models how processes like 3D boundary grouping and surface filling-in interact in multiple stages within and between the V1 interblob—V2 interstripe—V4 cortical stream and the V1 blob—V2 thin stripe—V4 cortical stream, respectively. Of particular importance for understanding figure-ground separation is how these cortical interactions convert computationally complementary boundary and surface mechanisms into a consistent conscious percept, including the critical use of surface contour feedback signals from surface representations in V2 thin stripes to boundary representations in V2 interstripes. Remarkably, key figure-ground properties emerge from these feedback interactions. The second research stream shows how cells that compute absolute disparity

Cortical Dynamics of Figure-Ground Separation in Response to 2D Pictures and 3D Scenes: How V2 Combines Border Ownership, Stereoscopic Cues, and Gestalt Grouping Rules.

Science.gov (United States)

Grossberg, Stephen

2015-01-01

The FACADE model, and its laminar cortical realization and extension in the 3D LAMINART model, have explained, simulated, and predicted many perceptual and neurobiological data about how the visual cortex carries out 3D vision and figure-ground perception, and how these cortical mechanisms enable 2D pictures to generate 3D percepts of occluding and occluded objects. In particular, these models have proposed how border ownership occurs, but have not yet explicitly explained the correlation between multiple properties of border ownership neurons in cortical area V2 that were reported in a remarkable series of neurophysiological experiments by von der Heydt and his colleagues; namely, border ownership, contrast preference, binocular stereoscopic information, selectivity for side-of-figure, Gestalt rules, and strength of attentional modulation, as well as the time course during which such properties arise. This article shows how, by combining 3D LAMINART properties that were discovered in two parallel streams of research, a unified explanation of these properties emerges. This explanation proposes, moreover, how these properties contribute to the generation of consciously seen 3D surfaces. The first research stream models how processes like 3D boundary grouping and surface filling-in interact in multiple stages within and between the V1 interblob-V2 interstripe-V4 cortical stream and the V1 blob-V2 thin stripe-V4 cortical stream, respectively. Of particular importance for understanding figure-ground separation is how these cortical interactions convert computationally complementary boundary and surface mechanisms into a consistent conscious percept, including the critical use of surface contour feedback signals from surface representations in V2 thin stripes to boundary representations in V2 interstripes. Remarkably, key figure-ground properties emerge from these feedback interactions. The second research stream shows how cells that compute absolute disparity in

Volcanic Plume Elevation Model Derived From Landsat 8: examples on Holuhraun (Iceland) and Mount Etna (Italy)

Science.gov (United States)

de Michele, Marcello; Raucoules, Daniel; Arason, Þórður; Spinetti, Claudia; Corradini, Stefano; Merucci, Luca

2016-04-01

The retrieval of both height and velocity of a volcanic plume is an important issue in volcanology. As an example, it is known that large volcanic eruptions can temporarily alter the climate, causing global cooling and shifting precipitation patterns; the ash/gas dispersion in the atmosphere, their impact and lifetime around the globe, greatly depends on the injection altitude. Plume height information is critical for ash dispersion modelling and air traffic security. Furthermore, plume height during explosive volcanism is the primary parameter for estimating mass eruption rate. Knowing the plume altitude is also important to get the correct amount of SO2 concentration from dedicated spaceborne spectrometers. Moreover, the distribution of ash deposits on ground greatly depends on the ash cloud altitude, which has an impact on risk assessment and crisis management. Furthermore, a spatially detailed plume height measure could be used as a hint for gas emission rate estimation and for ash plume volume researches, which both have an impact on climate research, air quality assessment for aviation and finally for the understanding of the volcanic system itself as ash/gas emission rates are related to the state of pressurization of the magmatic chamber. Today, the community mainly relies on ground based measurements but often they can be difficult to collect as by definition volcanic areas are dangerous areas (presence of toxic gases) and can be remotely situated and difficult to access. Satellite remote sensing offers a comprehensive and safe way to estimate plume height. Conventional photogrammetric restitution based on satellite imagery fails in precisely retrieving a plume elevation model as the plume own velocity induces an apparent parallax that adds up to the standard parallax given by the stereoscopic view. Therefore, measurements based on standard satellite photogrammeric restitution do not apply as there is an ambiguity in the measurement of the plume position

A study on correlation between stereographic cinematography and storytelling: through a documentary film about Ho Quyen-UNESCO World heritage in Vietnam

Science.gov (United States)

Choi, Yang Hyun; Ahn, Jaehong

2010-02-01

Nowadays stereoscopic technology is being paid attention as a leading technology for the next generation film industry in many countries including Korea. In Korean stereoscopic film production, however, the quality but also the quantity of stereoscopic contents still leaves much to be desired, and know-how and skill of stereoscopic film production has been elevated in tardy progress. This paper shows a research on the correlation between stereoscopic cinematography and storytelling. Based on a casestudy of a documentary film about Ho Quyen, UNESCO World Heritage in Vietnam, we could deliver guidelines for the stereoscopic film production and storytelling. For this study, we analyzed scenes and shots of a documentary film script in pre-production stage. These analysis results were reflected on a storyboard. A stereographer grasped the idea of a storytelling that a director had meant through a script and storyboard. Then he applied suitable parameters for a stereoscopic cinematography to every shot with a beamsplitter rig. A researcher wrote major parameters like interaxial distance, convergence angle in every shot. Then average parameter values of scenes were calculated from the parameter database, and the relationship between stereoscopic cinematography and storytelling was derived by shot-by-shot analysis.

Retinopathy screening in patients with type 1 diabetes diagnosed in young age using a non-mydriatic digital stereoscopic retinal imaging.

Science.gov (United States)

Minuto, N; Emmanuele, V; Vannati, M; Russo, C; Rebora, C; Panarello, S; Pistorio, A; Lorini, R; d'Annunzio, G

2012-04-01

Diabetic retinopathy seriously impairs patients' quality of life, since it represents the first cause of blindness in industrialized countries. To estimate prevalence of retinopathy in young Type 1 diabetes patients using a non-mydriatic digital stereoscopic retinal imaging (NMDSRI), and to evaluate the impact of socio-demographic, clinical, and metabolic variables. In 247 young patients glycated hemoglobin (HbA1c), gender, age, pubertal stage, presence of diabetic ketoacidosis (DKA), HLA-DQ heterodimers of susceptibility for Type 1 diabetes, and β-cell autoimmunity at clinical onset were considered. At retinopathy screening, we evaluated age, disease duration, pubertal stage, body mass index (BMI-SDS), insulin requirement, HbA1c levels, other autoimmune diseases, diabetes-related complications, serum concentrations of cholesterol and triglycerides, systolic and diastolic blood pressure. Retinopathy was found in 26/247 patients: 25 showed background retinopathy, and 1 had a sight-threatening retinopathy. A significant relationship between retinopathy and female gender (p=0.01), duration of disease ≥15 yr (p65 mg/dl (p=0.012) and mean HbA1c ≥7.5% or >9% (p=0.0014) were found at the multivariate logistic analysis. Metabolic control is the most important modifiable factor and promotion of continuous educational process to reach a good metabolic control is a cornerstone to prevent microangiopathic complications. Symptoms appear when the complication is already established; a screening program with an early diagnosis is mandatory to prevent an irreversible damage.

Comparison of film and digital fundus photographs in eyes of individuals with diabetes mellitus

DEFF Research Database (Denmark)

Gangaputra, Sapna; Almukhtar, Talat; Glassman, Adam R

2011-01-01

To compare grading of diabetic retinopathy (DR) and diabetic macular edema (DME) from stereoscopic film versus stereoscopic digital photographs obtained from a subset of Diabetic Retinopathy Clinical Research Network (DRCR.net) participants.......To compare grading of diabetic retinopathy (DR) and diabetic macular edema (DME) from stereoscopic film versus stereoscopic digital photographs obtained from a subset of Diabetic Retinopathy Clinical Research Network (DRCR.net) participants....

Reduction of Military Vehicle Acquisition Time and Cost through Advanced Modelling and Virtual Simulation (La reduction des couts et des delais d’acquisition des vehicules militaires par la modelisation avancee et la simulation de produit virtuel)

Science.gov (United States)

2003-03-01

aspect of performance and durability than their predecessors. Also, emphasis on reducing radar and infrared signature, and multi-axis thrust vectoring...projectors (Model 9500/P43). Also required are Liquid Crystal Display (LCD) stereoscopic shutter glasses (one set for each user), infrared (IR) emitters...issuing certificate of airworthiness. After the WW2 , it has broadened its scope of activity onto the design of flying apparatus of sorts. The successful

Instruments and Methodologies for the Underwater Tridimensional Digitization and Data Musealization

Science.gov (United States)

Repola, L.; Memmolo, R.; Signoretti, D.

2015-04-01

In the research started within the SINAPSIS project of the Università degli Studi Suor Orsola Benincasa an underwater stereoscopic scanning aimed at surveying of submerged archaeological sites, integrable to standard systems for geomorphological detection of the coast, has been developed. The project involves the construction of hardware consisting of an aluminum frame supporting a pair of GoPro Hero Black Edition cameras and software for the production of point clouds and the initial processing of data. The software has features for stereoscopic vision system calibration, reduction of noise and the of distortion of underwater captured images, searching for corresponding points of stereoscopic images using stereo-matching algorithms (dense and sparse), for points cloud generating and filtering. Only after various calibration and survey tests carried out during the excavations envisaged in the project, the mastery of methods for an efficient acquisition of data has been achieved. The current development of the system has allowed generation of portions of digital models of real submerged scenes. A semi-automatic procedure for global registration of partial models is under development as a useful aid for the study and musealization of sites.

PLOT3D (version-5): a computer code for drawing three dimensional graphs, maps and histograms, in single or multiple colours, for mono or stereoscopic viewing

International Nuclear Information System (INIS)

Jayaswal, Balhans

1987-01-01

PLOT3D series of graphic codes (version 1 to 5) have been developed for drawing three dimensional graphs, maps, histograms and simple layout diagrams on monochrome or colour raster graphic terminal and plotter. Of these, PLOT3D Version-5 is an advanced code, equipped with several features that make it specially suitable for drawing 3D maps, multicolour 3D and contour graphs, and 3D layout diagrams, in axonometric or perspective projection. Prior to drawing, graphic parameters that define orientation, magnification, smoothening, shading, colour-map, etc. of the figure can be selected interactively by means of simple commands on the user terminal, or by reading those commands from an input data file. This code requires linking with any one of three supporting libraries: PLOT 10 TCS, PLOT 10 IGL, and CALCOMP, and the figure can be plotted in single colour, or displayed in single or multiple colours depending upon the type of library support and output device. Furthermore, this code can also be used to plot left and right eye view projections of 3D figure for composing a stereoscopic image from them with the aid of a viewer. 14 figures. (author)

Whole object surface area and volume of partial-view 3D models

International Nuclear Information System (INIS)

Mulukutla, Gopal K; Proussevitch, Alexander A; Genareau, Kimberly D; Durant, Adam J

2017-01-01

Micro-scale 3D models, important components of many studies in science and engineering, are often used to determine morphological characteristics such as shape, surface area and volume. The application of techniques such as stereoscopic scanning electron microscopy on whole objects often results in ‘partial-view’ models with a portion of object not within the field of view thus not captured in the 3D model. The nature and extent of the surface not captured is dependent on the complex interaction of imaging system attributes (e.g. working distance, viewing angle) with object size, shape and morphology. As a result, any simplistic assumptions in estimating whole object surface area or volume can lead to significant errors. In this study, we report on a novel technique to estimate the physical fraction of an object captured in a partial-view 3D model of an otherwise whole object. This allows a more accurate estimate of surface area and volume. Using 3D models, we demonstrate the robustness of this method and the accuracy of surface area and volume estimates relative to true values. (paper)

If you watch it move, you'll recognize it in 3D: Transfer of depth cues between encoding and retrieval.

Science.gov (United States)

Papenmeier, Frank; Schwan, Stephan

2016-02-01

Viewing objects with stereoscopic displays provides additional depth cues through binocular disparity supporting object recognition. So far, it was unknown whether this results from the representation of specific stereoscopic information in memory or a more general representation of an object's depth structure. Therefore, we investigated whether continuous object rotation acting as depth cue during encoding results in a memory representation that can subsequently be accessed by stereoscopic information during retrieval. In Experiment 1, we found such transfer effects from continuous object rotation during encoding to stereoscopic presentations during retrieval. In Experiments 2a and 2b, we found that the continuity of object rotation is important because only continuous rotation and/or stereoscopic depth but not multiple static snapshots presented without stereoscopic information caused the extraction of an object's depth structure into memory. We conclude that an object's depth structure and not specific depth cues are represented in memory. Copyright © 2015 Elsevier B.V. All rights reserved.

S3D depth-axis interaction for video games: performance and engagement

Science.gov (United States)

Zerebecki, Chris; Stanfield, Brodie; Hogue, Andrew; Kapralos, Bill; Collins, Karen

2013-03-01

Game developers have yet to embrace and explore the interactive stereoscopic 3D medium. They typically view stereoscopy as a separate mode that can be disabled throughout the design process and rarely develop game mechanics that take advantage of the stereoscopic 3D medium. What if we designed games to be S3D-specific and viewed traditional 2D viewing as a separate mode that can be disabled? The design choices made throughout such a process may yield interesting and compelling results. Furthermore, we believe that interaction within a stereoscopic 3D environment is more important than the visual experience itself and therefore, further exploration is needed to take into account the interactive affordances presented by stereoscopic 3D displays. Stereoscopic 3D displays allow players to perceive objects at different depths, thus we hypothesize that designing a core mechanic to take advantage of this viewing paradigm will create compelling content. In this paper, we describe Z-Fighter a game that we have developed that requires the player to interact directly along the stereoscopic 3D depth axis. We also outline an experiment conducted to investigate the performance, perception, and enjoyment of this game in stereoscopic 3D vs. traditional 2D viewing.

The TeV γ-ray binary PSR B1259-63. Observations with the high energy stereoscopic system in the years 2005-2007

International Nuclear Information System (INIS)

Kerschhaggl, Matthias

2010-01-01

PSR B1259-63/SS2883 is a binary system where a 48 ms pulsar orbits a massive Be star with a period of 3.4 years. The system exhibits variable, non-thermal radiation around periastron on the highly eccentric orbit (e=0.87) visible from radio to very high energies (VHE; E>100 GeV). When being detected in TeV γ-rays with the High Energy Stereoscopic System (H.E.S.S.) in 2004 it became known as the first variable galactic VHE source. This thesis presents VHE data from PSR B1259-63 as taken during the years 2005, 2006 and before as well as shortly after the 2007 periastron passage. These data extend the knowledge of the lightcurve of this object to all phases of the binary orbit. The lightcurve constrains physical mechanisms present in this TeV source. Observations of VHE γ-rays with the H.E.S.S. telescope array using the Imaging Atmospheric Cherenkov Technique were performed. The H.E.S.S. instrument features an angular resolution of stat ±0.2 sys and flux normalisation Φ 0 =(1.1±0.1 stat ±0.2 sys ) x 10 -12 TeV -1 cm -2 s -1 . PSR B1259-63 was also monitored in 2005 and 2006, far from periastron passage, comprising 8.9 h and 7.5 h of exposure, respectively. No significant excess of γ-rays is seen in those observations. PSR B1259-63 has been re-confirmed as a variable TeV γ-ray emitter. The firm detection of VHE photons emitted at a true anomaly θ∼0.35 of the pulsar orbit, i.e. already ∝50 days prior to the periastron passage, disfavors the stellar disc target scenario as a primary emission mechanism, based on current knowledge about the companion star's disc inclination, extension, and density profile. In a phenomenological study indirect evidence that PSR B1259-63 could in fact be a periodical VHE emitter is presented using the TeV data discussed in this work. While the TeV energy flux level seems to be only dependent on the binary separation this behavior is not seen in X-rays. Moreover, model calculations based on inverse compton (IC) scattering of

3D Displays for Battle Management

Science.gov (United States)

1990-04-01

cinematography industry, were found to be inadequate for providing comfortable stereoscopic out-the-window terrain scenes, when viewed from a 19-inch...JStereoscoDic Projection GeomietrvL Existing stereoscopic drawing / fechniques, which have roots in t cinematography industry, were , found to be...the- art graphics workstations. The LCSSs evaluated in this report can switch each left and right eye view at 120 liz so i:hat the stereoscopic image

2D and 3D stereoscopic videos used as pre-anatomy lab tools improve students' examination performance in a veterinary gross anatomy course.

Science.gov (United States)

Al-Khalili, Sereen M; Coppoc, Gordon L

2014-01-01

The hypothesis for the research described in this article was that viewing an interactive two-dimensional (2D) or three-dimensional (3D) stereoscopic pre-laboratory video would improve efficiency and learning in the laboratory. A first-year DVM class was divided into 21 dissection teams of four students each. Primary variables were method of preparation (2D, 3D, or laboratory manual) and dissection region (thorax, abdomen, or pelvis). Teams were randomly assigned to a group (A, B, or C) in a crossover design experiment so that all students experienced each of the modes of preparation, but with different regions of the canine anatomy. All students were instructed to study normal course materials and the laboratory manual, the Guide, before coming to the laboratory session and to use them during the actual dissection as usual. Video groups were given a DVD with an interactive 10-12 minute video to view for the first 30 minutes of the laboratory session, while non-video groups were instructed to review the Guide. All groups were allowed 45 minutes to dissect the assigned section and find a list of assigned structures, after which all groups took a post-dissection quiz and attitudinal survey. The 2D groups performed better than the Guide groups (p=.028) on the post-dissection quiz, despite the fact that only a minority of the 2D-group students studied the Guide as instructed. There was no significant difference (p>.05) between 2D and 3D groups on the post-dissection quiz. Students preferred videos over the Guide.

Automatic relative RPC image model bias compensation through hierarchical image matching for improving DEM quality

Science.gov (United States)

Noh, Myoung-Jong; Howat, Ian M.

2018-02-01

The quality and efficiency of automated Digital Elevation Model (DEM) extraction from stereoscopic satellite imagery is critically dependent on the accuracy of the sensor model used for co-locating pixels between stereo-pair images. In the absence of ground control or manual tie point selection, errors in the sensor models must be compensated with increased matching search-spaces, increasing both the computation time and the likelihood of spurious matches. Here we present an algorithm for automatically determining and compensating the relative bias in Rational Polynomial Coefficients (RPCs) between stereo-pairs utilizing hierarchical, sub-pixel image matching in object space. We demonstrate the algorithm using a suite of image stereo-pairs from multiple satellites over a range stereo-photogrammetrically challenging polar terrains. Besides providing a validation of the effectiveness of the algorithm for improving DEM quality, experiments with prescribed sensor model errors yield insight into the dependence of DEM characteristics and quality on relative sensor model bias. This algorithm is included in the Surface Extraction through TIN-based Search-space Minimization (SETSM) DEM extraction software package, which is the primary software used for the U.S. National Science Foundation ArcticDEM and Reference Elevation Model of Antarctica (REMA) products.

PIV study of the effect of piston position on the in-cylinder swirling flow during the scavenging process in large two-stroke marine diesel engines

DEFF Research Database (Denmark)

Haider, Sajjad; Schnipper, Teis; Obeidat, Anas

2013-01-01

A simplified model of a low speed large twostroke marine diesel engine cylinder is developed. The effect of piston position on the in-cylinder swirling flow during the scavenging process is studied using the stereoscopic particle image velocimetry technique. The measurements are conducted...

Effect of Viewing Conditions on Sickness and Distance Estimation in a Virtual Environment

National Research Council Canada - National Science Library

Ehrlich, Jennifer

2000-01-01

..., referred to as vergence movements. The present study examined the effects of a vergence algorithm moderating the stereoscopic display in an HMD in a within subjects comparison to standard stereoscopic and biocular presentations...

A medaka model of cancer allowing direct observation of transplanted tumor cells in vivo at a cellular-level resolution.

Science.gov (United States)

Hasegawa, Sumitaka; Maruyama, Kouichi; Takenaka, Hikaru; Furukawa, Takako; Saga, Tsuneo

2009-08-18

The recent success with small fish as an animal model of cancer with the aid of fluorescence technique has attracted cancer modelers' attention because it would be possible to directly visualize tumor cells in vivo in real time. Here, we report a medaka model capable of allowing the observation of various cell behaviors of transplanted tumor cells, such as cell proliferation and metastasis, which were visualized easily in vivo. We established medaka melanoma (MM) cells stably expressing GFP and transplanted them into nonirradiated and irradiated medaka. The tumor cells were grown at the injection sites in medaka, and the spatiotemporal changes were visualized under a fluorescence stereoscopic microscope at a cellular-level resolution, and even at a single-cell level. Tumor dormancy and metastasis were also observed. Interestingly, in irradiated medaka, accelerated tumor growth and metastasis of the transplanted tumor cells were directly visualized. Our medaka model provides an opportunity to visualize in vivo tumor cells "as seen in a culture dish" and would be useful for in vivo tumor cell biology.

Change Blindness Phenomena for Virtual Reality Display Systems.

Science.gov (United States)

Steinicke, Frank; Bruder, Gerd; Hinrichs, Klaus; Willemsen, Pete

2011-09-01

In visual perception, change blindness describes the phenomenon that persons viewing a visual scene may apparently fail to detect significant changes in that scene. These phenomena have been observed in both computer-generated imagery and real-world scenes. Several studies have demonstrated that change blindness effects occur primarily during visual disruptions such as blinks or saccadic eye movements. However, until now the influence of stereoscopic vision on change blindness has not been studied thoroughly in the context of visual perception research. In this paper, we introduce change blindness techniques for stereoscopic virtual reality (VR) systems, providing the ability to substantially modify a virtual scene in a manner that is difficult for observers to perceive. We evaluate techniques for semiimmersive VR systems, i.e., a passive and active stereoscopic projection system as well as an immersive VR system, i.e., a head-mounted display, and compare the results to those of monoscopic viewing conditions. For stereoscopic viewing conditions, we found that change blindness phenomena occur with the same magnitude as in monoscopic viewing conditions. Furthermore, we have evaluated the potential of the presented techniques for allowing abrupt, and yet significant, changes of a stereoscopically displayed virtual reality environment.

Visual discomfort and depth-of-field

NARCIS (Netherlands)

O'Hare, L.; Zhang, T.; Nefs, H.T.; Hibbard, P.B.

2013-01-01

Visual discomfort has been reported for certain visual stimuli and under particular viewing conditions, such as stereoscopic viewing. In stereoscopic viewing, visual discomfort can be caused by a conflict between accommodation and convergence cues that may specify different distances in depth.

Interactive Visual Analysis within Dynamic Ocean Models

Science.gov (United States)

Butkiewicz, T.

2012-12-01

The many observation and simulation based ocean models available today can provide crucial insights for all fields of marine research and can serve as valuable references when planning data collection missions. However, the increasing size and complexity of these models makes leveraging their contents difficult for end users. Through a combination of data visualization techniques, interactive analysis tools, and new hardware technologies, the data within these models can be made more accessible to domain scientists. We present an interactive system that supports exploratory visual analysis within large-scale ocean flow models. The currents and eddies within the models are illustrated using effective, particle-based flow visualization techniques. Stereoscopic displays and rendering methods are employed to ensure that the user can correctly perceive the complex 3D structures of depth-dependent flow patterns. Interactive analysis tools are provided which allow the user to experiment through the introduction of their customizable virtual dye particles into the models to explore regions of interest. A multi-touch interface provides natural, efficient interaction, with custom multi-touch gestures simplifying the otherwise challenging tasks of navigating and positioning tools within a 3D environment. We demonstrate the potential applications of our visual analysis environment with two examples of real-world significance: Firstly, an example of using customized particles with physics-based behaviors to simulate pollutant release scenarios, including predicting the oil plume path for the 2010 Deepwater Horizon oil spill disaster. Secondly, an interactive tool for plotting and revising proposed autonomous underwater vehicle mission pathlines with respect to the surrounding flow patterns predicted by the model; as these survey vessels have extremely limited energy budgets, designing more efficient paths allows for greater survey areas.

[3-D reconstruction of the breast implants from isocentric stereoscopic x-ray images for the application monitoring and irradiation planning of a remote-controlled interstitial afterloading method].

Science.gov (United States)

Löffler, E; Sauer, O

1988-01-01

An individual irradiation planning and application monitoring by ISXP is presented for a remote-controlled interstitial afterloading technique using 192Ir wires which is applied in breast-preserving radiotherapy. The errors of reconstruction of the implants are discussed. The consideration of errors for ISXP can be extended to other stereoscopic methods. In this case the quality considerations made by other authors have to be enlarged. The maximum reconstruction error was investigated for a given digitalization precision, focus size, and object blur by patient's movements in dependence on the deviation angle. The optimum deviation angle is about 45 degrees, depending on the importance given to the individual parts and almost without being influenced by the relation between the isocenter-film and the focus-isocenter distances. In case of an optimized deviation angle, a displacement of an implant point of 1 mm leads to a maximum reconstruction error of 2 mm. The dosage is made according to the Paris system. If the circumcircle radius of the application triangle is modified by 1 mm, a dosage modification of 14% will be the consequence in case of very short wires and a small side length. A verification in a phantom showed a positioning error below 0.5 mm. The dosage error is 2% due to the mutual compensation of the direction-isotropic reconstruction errors of the needles the number of which is between seven and nine.

Three-dimensional reconstruction of breast implants based on isocentric stereoscopic X-ray pictures (ISXP) for application monitoring and irradiation planning of a remote-controlled interstitial afterloading method

Energy Technology Data Exchange (ETDEWEB)

Loeffler, E.; Sauer, O.

1988-01-01

An individual irradiation planning and application monitoring by ISXP is presented for a remote-controlled interstitial afterloading technique using /sup 192/Ir wires which is applied in breast-preserving radiotherapy. The errors of reconstruction of the implants are discussed. The consideration of errors for ISXP can be extended to other stereoscopic methods. In this case the quality considerations made by other authors have to be enlarged. The maximum reconstruction error was investigated for a given digitalization precision, focus size, and object blur by patient's movements in dependence on the deviation angle. The optimum deviation angle is about 45/sup 0/, depending on the importance given to the individual parts and almost without being influenced by the relation between the distance isocenter-film and the distance focus-isocenter. In case of an optimized deviation angle, a displacement of an implant point of 1 mm leads to a maximum reconstruction error of 2 mm. The dosage is made according to the Paris system. If the circumcircle radius of the application triangle is modified by 1 mm, a dosage modification of 14% will be the consequence in case of very short wires and a small side length. A verification in a phantom showed a positioning error below 0.5 mm. The dosage error is 2% due to the mutual compensation of the direction-isotropic reconstruction errors of the needles the number of which is between seven and nine.

Virtual Reality, 3D Stereo Visualization, and Applications in Robotics

DEFF Research Database (Denmark)

Livatino, Salvatore

2006-01-01

, while little can be found about the advantages of stereoscopic visualization in mobile robot tele-guide applications. This work investigates stereoscopic robot tele-guide under different conditions, including typical navigation scenarios and the use of synthetic and real images. This work also...

Identification and visualisation of possible ancient ocean shoreline on Mars using submeter-resolution Digital Terrain Models

Science.gov (United States)

Świąder, Andrzej

2014-12-01

Digital Terrain Models (DTMs) produced from stereoscopic, submeter-resolution High Resolution Imaging Science Experiment (HiRISE) imagery provide a solid basis for all morphometric analyses of the surface of Mars. In view of the fact that a more effective use of DTMs is hindered by complicated and time-consuming manual handling, the automated process provided by specialists of the Ames Intelligent Robotics Group (NASA), Ames Stereo Pipeline, constitutes a good alternative. Four DTMs, covering the global dichotomy boundary between the southern highlands and northern lowlands along the line of the presumable Arabia shoreline, were produced and analysed. One of them included forms that are likely to be indicative of an oceanic basin that extended across the lowland northern hemisphere of Mars in the geological past. The high resolution DTMs obtained were used in the process of landscape visualisation.

Programming standards for effective S-3D game development

Science.gov (United States)

Schneider, Neil; Matveev, Alexander

2008-02-01

When a video game is in development, more often than not it is being rendered in three dimensions - complete with volumetric depth. It's the PC monitor that is taking this three-dimensional information, and artificially displaying it in a flat, two-dimensional format. Stereoscopic drivers take the three-dimensional information captured from DirectX and OpenGL calls and properly display it with a unique left and right sided view for each eye so a proper stereoscopic 3D image can be seen by the gamer. The two-dimensional limitation of how information is displayed on screen has encouraged programming short-cuts and work-arounds that stifle this stereoscopic 3D effect, and the purpose of this guide is to outline techniques to get the best of both worlds. While the programming requirements do not significantly add to the game development time, following these guidelines will greatly enhance your customer's stereoscopic 3D experience, increase your likelihood of earning Meant to be Seen certification, and give you instant cost-free access to the industry's most valued consumer base. While this outline is mostly based on NVIDIA's programming guide and iZ3D resources, it is designed to work with all stereoscopic 3D hardware solutions and is not proprietary in any way.

3D-TV System with Depth-Image-Based Rendering Architectures, Techniques and Challenges

CERN Document Server

Zhao, Yin; Yu, Lu; Tanimoto, Masayuki

2013-01-01

Riding on the success of 3D cinema blockbusters and advances in stereoscopic display technology, 3D video applications have gathered momentum in recent years. 3D-TV System with Depth-Image-Based Rendering: Architectures, Techniques and Challenges surveys depth-image-based 3D-TV systems, which are expected to be put into applications in the near future. Depth-image-based rendering (DIBR) significantly enhances the 3D visual experience compared to stereoscopic systems currently in use. DIBR techniques make it possible to generate additional viewpoints using 3D warping techniques to adjust the perceived depth of stereoscopic videos and provide for auto-stereoscopic displays that do not require glasses for viewing the 3D image.   The material includes a technical review and literature survey of components and complete systems, solutions for technical issues, and implementation of prototypes. The book is organized into four sections: System Overview, Content Generation, Data Compression and Transmission, and 3D V...

Quality assurance of a system for improved target localization and patient set-up that combines real-time infrared tracking and stereoscopic X-ray imaging.

Science.gov (United States)

Verellen, Dirk; Soete, Guy; Linthout, Nadine; Van Acker, Swana; De Roover, Patsy; Vinh-Hung, Vincent; Van de Steene, Jan; Storme, Guy

2003-04-01

The aim of this study is to investigate the positional accuracy of a prototype X-ray imaging tool in combination with a real-time infrared tracking device allowing automated patient set-up in three dimensions. A prototype X-ray imaging tool has been integrated with a commercially released real-time infrared tracking device. The system, consisting of two X-ray tubes mounted to the ceiling and a centrally located amorphous silicon detector has been developed for automated patient positioning from outside the treatment room prior to treatment. Two major functions are supported: (a) automated fusion of the actual treatment images with digitally reconstructed radiographs (DRRs) representing the desired position; (b) matching of implanted radio opaque markers. Measurements of known translational (up to 30.0mm) and rotational (up to 4.0 degrees ) set-up errors in three dimensions as well as hidden target tests have been performed on anthropomorphic phantoms. The system's accuracy can be represented with the mean three-dimensional displacement vector, which yielded 0.6mm (with an overall SD of 0.9mm) for the fusion of DRRs and X-ray images. Average deviations between known translational errors and calculations varied from -0.3 to 0.6mm with a standard deviation in the range of 0.6-1.2mm. The marker matching algorithm yielded a three-dimensional uncertainty of 0.3mm (overall SD: 0.4mm), with averages ranging from 0.0 to 0.3mm and a standard deviation in the range between 0.3 and 0.4mm. The stereoscopic X-ray imaging device integrated with the real-time infrared tracking device represents a positioning tool allowing for the geometrical accuracy that is required for conformal radiation therapy of abdominal and pelvic lesions, within an acceptable time-frame.

Hands-on guide for 3D image creation for geological purposes

Science.gov (United States)

Frehner, Marcel; Tisato, Nicola

2013-04-01

Geological structures in outcrops or hand specimens are inherently three dimensional (3D), and therefore better understandable if viewed in 3D. While 3D models can easily be created, manipulated, and looked at from all sides on the computer screen (e.g., using photogrammetry or laser scanning data), 3D visualizations for publications or conference posters are much more challenging as they have to live in a 2D-world (i.e., on a sheet of paper). Perspective 2D visualizations of 3D models do not fully transmit the "feeling and depth of the third dimension" to the audience; but this feeling is desirable for a better examination and understanding in 3D of the structure under consideration. One of the very few possibilities to generate real 3D images, which work on a 2D display, is by using so-called stereoscopic images. Stereoscopic images are two images of the same object recorded from two slightly offset viewpoints. Special glasses and techniques have to be used to make sure that one image is seen only by one eye, and the other image is seen by the other eye, which together lead to the "3D effect". Geoscientists are often familiar with such 3D images. For example, geomorphologists traditionally view stereographic orthophotos by employing a mirror-steroscope. Nowadays, petroleum-geoscientists examine high-resolution 3D seismic data sets in special 3D visualization rooms. One of the methods for generating and viewing a stereoscopic image, which does not require a high-tech viewing device, is to create a so-called anaglyph. The principle is to overlay two images saturated in red and cyan, respectively. The two images are then viewed through red-cyan-stereoscopic glasses. This method is simple and cost-effective, but has some drawbacks in preserving colors accurately. A similar method is used in 3D movies, where polarized light or shuttering techniques are used to separate the left from the right image, which allows preserving the original colors. The advantage of red

A Feasibility Study into the Use of Three-Dimensional Printer Modelling in Acetabular Fracture Surgery

Directory of Open Access Journals (Sweden)

A. W. Yu

2015-01-01

Full Text Available There are a number of challenges associated with the operative treatment of acetabular fractures. The approach used is often extensive, while operative time and perioperative blood loss can also be significant. With the proliferation of 3D printer technology, we present a fast and economical way to aid the operative planning of complex fractures. We used augmented stereoscopic 3D CT reconstructions to allow for an appreciation of the normal 3D anatomy of the pelvis on the fractured side and to use the models for subsequent intraoperative contouring of pelvic reconstruction plates. This leads to a reduction in the associated soft tissue trauma, reduced intraoperative time and blood loss, minimal handling of the plate, and reduced fluoroscopic screening times. We feel that the use of this technology to customize implants, plates, and the operative procedure to a patient’s unique anatomy can only lead to improved outcomes.

Perception and cognition of depth of field

NARCIS (Netherlands)

Zhang, T.

2015-01-01

A common way to present 3D materials to human observers nowadays is by stereoscopic displaying on 3D TVs or head-mounted displays such as the Oculus Rift. However, not everyone can see three-dimensional solid shape from stereoscopic viewing and the three-dimensional images remain two-dimensional

Stereoscopy in Static Scientific Imagery in an Informal Education Setting: Does It Matter?

Science.gov (United States)

Price, C. Aaron; Lee, H.-S.; Malatesta, K.

2014-01-01

Stereoscopic technology (3D) is rapidly becoming ubiquitous across research, entertainment and informal educational settings. Children of today may grow up never knowing a time when movies, television and video games were not available stereoscopically. Despite this rapid expansion, the field's understanding of the impact of stereoscopic…

INVESTIGATION OF 1 : 1,000 SCALE MAP GENERATION BY STEREO PLOTTING USING UAV IMAGES

Directory of Open Access Journals (Sweden)

S. Rhee

2017-08-01

Full Text Available Large scale maps and image mosaics are representative geospatial data that can be extracted from UAV images. Map drawing using UAV images can be performed either by creating orthoimages and digitizing them, or by stereo plotting. While maps generated by digitization may serve the need for geospatial data, many institutions and organizations require map drawing using stereoscopic vision on stereo plotting systems. However, there are several aspects to be checked for UAV images to be utilized for stereo plotting. The first aspect is the accuracy of exterior orientation parameters (EOPs generated through automated bundle adjustment processes. It is well known that GPS and IMU sensors mounted on a UAV are not very accurate. It is necessary to adjust initial EOPs accurately using tie points. For this purpose, we have developed a photogrammetric incremental bundle adjustment procedure. The second aspect is unstable shooting conditions compared to aerial photographing. Unstable image acquisition may bring uneven stereo coverage, which will result in accuracy loss eventually. Oblique stereo pairs will create eye fatigue. The third aspect is small coverage of UAV images. This aspect will raise efficiency issue for stereo plotting of UAV images. More importantly, this aspect will make contour generation from UAV images very difficult. This paper will discuss effects relate to these three aspects. In this study, we tried to generate 1 : 1,000 scale map from the dataset using EOPs generated from software developed in-house. We evaluated Y-disparity of the tie points extracted automatically through the photogrammetric incremental bundle adjustment process. We could confirm that stereoscopic viewing is possible. Stereoscopic plotting work was carried out by a professional photogrammetrist. In order to analyse the accuracy of the map drawing using stereoscopic vision, we compared the horizontal and vertical position difference between adjacent models after

Investigation of 1 : 1,000 Scale Map Generation by Stereo Plotting Using Uav Images

Science.gov (United States)

Rhee, S.; Kim, T.

2017-08-01

Large scale maps and image mosaics are representative geospatial data that can be extracted from UAV images. Map drawing using UAV images can be performed either by creating orthoimages and digitizing them, or by stereo plotting. While maps generated by digitization may serve the need for geospatial data, many institutions and organizations require map drawing using stereoscopic vision on stereo plotting systems. However, there are several aspects to be checked for UAV images to be utilized for stereo plotting. The first aspect is the accuracy of exterior orientation parameters (EOPs) generated through automated bundle adjustment processes. It is well known that GPS and IMU sensors mounted on a UAV are not very accurate. It is necessary to adjust initial EOPs accurately using tie points. For this purpose, we have developed a photogrammetric incremental bundle adjustment procedure. The second aspect is unstable shooting conditions compared to aerial photographing. Unstable image acquisition may bring uneven stereo coverage, which will result in accuracy loss eventually. Oblique stereo pairs will create eye fatigue. The third aspect is small coverage of UAV images. This aspect will raise efficiency issue for stereo plotting of UAV images. More importantly, this aspect will make contour generation from UAV images very difficult. This paper will discuss effects relate to these three aspects. In this study, we tried to generate 1 : 1,000 scale map from the dataset using EOPs generated from software developed in-house. We evaluated Y-disparity of the tie points extracted automatically through the photogrammetric incremental bundle adjustment process. We could confirm that stereoscopic viewing is possible. Stereoscopic plotting work was carried out by a professional photogrammetrist. In order to analyse the accuracy of the map drawing using stereoscopic vision, we compared the horizontal and vertical position difference between adjacent models after drawing a specific

Application of stereo-imaging technology to medical field.

Science.gov (United States)

Nam, Kyoung Won; Park, Jeongyun; Kim, In Young; Kim, Kwang Gi

2012-09-01

There has been continuous development in the area of stereoscopic medical imaging devices, and many stereoscopic imaging devices have been realized and applied in the medical field. In this article, we review past and current trends pertaining to the application stereo-imaging technologies in the medical field. We describe the basic principles of stereo vision and visual issues related to it, including visual discomfort, binocular disparities, vergence-accommodation mismatch, and visual fatigue. We also present a brief history of medical applications of stereo-imaging techniques, examples of recently developed stereoscopic medical devices, and patent application trends as they pertain to stereo-imaging medical devices. Three-dimensional (3D) stereo-imaging technology can provide more realistic depth perception to the viewer than conventional two-dimensional imaging technology. Therefore, it allows for a more accurate understanding and analysis of the morphology of an object. Based on these advantages, the significance of stereoscopic imaging in the medical field increases in accordance with the increase in the number of laparoscopic surgeries, and stereo-imaging technology plays a key role in the diagnoses of the detailed morphologies of small biological specimens. The application of 3D stereo-imaging technology to the medical field will help improve surgical accuracy, reduce operation times, and enhance patient safety. Therefore, it is important to develop more enhanced stereoscopic medical devices.

Stereoscopy in Static Scientific Imagery in an Informal Education Setting: Does It Matter?

Science.gov (United States)

Price, C. Aaron; Lee, H.-S.; Malatesta, K.

2014-12-01

Stereoscopic technology (3D) is rapidly becoming ubiquitous across research, entertainment and informal educational settings. Children of today may grow up never knowing a time when movies, television and video games were not available stereoscopically. Despite this rapid expansion, the field's understanding of the impact of stereoscopic visualizations on learning is rather limited. Much of the excitement of stereoscopic technology could be due to a novelty effect, which will wear off over time. This study controlled for the novelty factor using a variety of techniques. On the floor of an urban science center, 261 children were shown 12 photographs and visualizations of highly spatial scientific objects and scenes. The images were randomly shown in either traditional (2D) format or in stereoscopic format. The children were asked two questions of each image—one about a spatial property of the image and one about a real-world application of that property. At the end of the test, the child was asked to draw from memory the last image they saw. Results showed no overall significant difference in response to the questions associated with 2D or 3D images. However, children who saw the final slide only in 3D drew more complex representations of the slide than those who did not. Results are discussed through the lenses of cognitive load theory and the effect of novelty on engagement.

Semi-Immersive Virtual Turbine Engine Simulation System

Science.gov (United States)

Abidi, Mustufa H.; Al-Ahmari, Abdulrahman M.; Ahmad, Ali; Darmoul, Saber; Ameen, Wadea

2018-05-01

The design and verification of assembly operations is essential for planning product production operations. Recently, virtual prototyping has witnessed tremendous progress, and has reached a stage where current environments enable rich and multi-modal interaction between designers and models through stereoscopic visuals, surround sound, and haptic feedback. The benefits of building and using Virtual Reality (VR) models in assembly process verification are discussed in this paper. In this paper, we present the virtual assembly (VA) of an aircraft turbine engine. The assembly parts and sequences are explained using a virtual reality design system. The system enables stereoscopic visuals, surround sounds, and ample and intuitive interaction with developed models. A special software architecture is suggested to describe the assembly parts and assembly sequence in VR. A collision detection mechanism is employed that provides visual feedback to check the interference between components. The system is tested for virtual prototype and assembly sequencing of a turbine engine. We show that the developed system is comprehensive in terms of VR feedback mechanisms, which include visual, auditory, tactile, as well as force feedback. The system is shown to be effective and efficient for validating the design of assembly, part design, and operations planning.

The TeV {gamma}-ray binary PSR B1259-63. Observations with the high energy stereoscopic system in the years 2005-2007

Energy Technology Data Exchange (ETDEWEB)

Kerschhaggl, Matthias

2010-04-06

PSR B1259-63/SS2883 is a binary system where a 48 ms pulsar orbits a massive Be star with a period of 3.4 years. The system exhibits variable, non-thermal radiation around periastron on the highly eccentric orbit (e=0.87) visible from radio to very high energies (VHE; E>100 GeV). When being detected in TeV {gamma}-rays with the High Energy Stereoscopic System (H.E.S.S.) in 2004 it became known as the first variable galactic VHE source. This thesis presents VHE data from PSR B1259-63 as taken during the years 2005, 2006 and before as well as shortly after the 2007 periastron passage. These data extend the knowledge of the lightcurve of this object to all phases of the binary orbit. The lightcurve constrains physical mechanisms present in this TeV source. Observations of VHE {gamma}-rays with the H.E.S.S. telescope array using the Imaging Atmospheric Cherenkov Technique were performed. The H.E.S.S. instrument features an angular resolution of < 0.1 and an energy resolution of < 20%. Gamma-ray events in an energy range of 0.5-70 TeV were recorded. From these data, energy spectra and lightcurve with a monthly time sampling were extracted. VHE {gamma}-ray emission from PSRB1259-63 was detected with an overall significance of 9.5 standard deviations using 55 h of exposure, obtained from April to August 2007. The monthly flux of -rays during the observation period was measured, yielding VHE lightcurve data for the early pre-periastron phase of the system for the first time. No spectral variability was found on timescales of months. The spectrum is described by a power law with a photon index of {gamma}=2.8{+-}0.2{sub stat}{+-}0.2{sub sys} and flux normalisation {phi}{sub 0}=(1.1{+-}0.1{sub stat}{+-}0.2{sub sys}) x 10{sup -12} TeV{sup -1}cm{sup -2}s{sup -1}. PSR B1259-63 was also monitored in 2005 and 2006, far from periastron passage, comprising 8.9 h and 7.5 h of exposure, respectively. No significant excess of {gamma}-rays is seen in those observations. PSR B1259-63 has

The TeV {gamma}-ray binary PSR B1259-63. Observations with the high energy stereoscopic system in the years 2005-2007

Energy Technology Data Exchange (ETDEWEB)

Kerschhaggl, Matthias

2010-04-06

PSR B1259-63/SS2883 is a binary system where a 48 ms pulsar orbits a massive Be star with a period of 3.4 years. The system exhibits variable, non-thermal radiation around periastron on the highly eccentric orbit (e=0.87) visible from radio to very high energies (VHE; E>100 GeV). When being detected in TeV {gamma}-rays with the High Energy Stereoscopic System (H.E.S.S.) in 2004 it became known as the first variable galactic VHE source. This thesis presents VHE data from PSR B1259-63 as taken during the years 2005, 2006 and before as well as shortly after the 2007 periastron passage. These data extend the knowledge of the lightcurve of this object to all phases of the binary orbit. The lightcurve constrains physical mechanisms present in this TeV source. Observations of VHE {gamma}-rays with the H.E.S.S. telescope array using the Imaging Atmospheric Cherenkov Technique were performed. The H.E.S.S. instrument features an angular resolution of < 0.1 and an energy resolution of < 20%. Gamma-ray events in an energy range of 0.5-70 TeV were recorded. From these data, energy spectra and lightcurve with a monthly time sampling were extracted. VHE {gamma}-ray emission from PSRB1259-63 was detected with an overall significance of 9.5 standard deviations using 55 h of exposure, obtained from April to August 2007. The monthly flux of -rays during the observation period was measured, yielding VHE lightcurve data for the early pre-periastron phase of the system for the first time. No spectral variability was found on timescales of months. The spectrum is described by a power law with a photon index of {gamma}=2.8{+-}0.2{sub stat}{+-}0.2{sub sys} and flux normalisation {phi}{sub 0}=(1.1{+-}0.1{sub stat}{+-}0.2{sub sys}) x 10{sup -12} TeV{sup -1}cm{sup -2}s{sup -1}. PSR B1259-63 was also monitored in 2005 and 2006, far from periastron passage, comprising 8.9 h and 7.5 h of exposure, respectively. No significant excess of {gamma}-rays is seen in those observations. PSR B1259-63 has

An Affordable Microsurgical Training System for a Beginning Neurosurgeon: How to Realize the Self-Training Laboratory.

Science.gov (United States)

Chung, Sang-Bong; Ryu, Jiwook; Chung, Yeongu; Lee, Sung Ho; Choi, Seok Keun

2017-09-01

To provide detailed information about how to realize a self-training laboratory with cost-effective microsurgical instruments, especially pertinent for the novice trainee. Our training model is designed to allow the practice of the microsurgery skills in an efficient and cost-effective manner. A used stereoscopic microscope is prepared for microsurgical training. A sufficient working distance for microsurgical practice is obtained by attaching an auxiliary objective lens. The minimum instrument list includes 2 jeweler's forceps, iris scissors, and alligator clips. The iris scissors and alligator clip provide good alternatives to micro-scissors and microvascular clamp. The short time needed to set up the microscope and suture the gauze with micro-forceps makes the training model suitable for daily practice. It takes about 15 minutes to suture 10 neighboring fibers of the gauze with 10-0 nylon; thus, training can be completed more quickly. We have developed an inexpensive and efficient micro-anastomosis training system using a stereoscopic microscope and minimal micro-instruments. Especially useful for novice trainees, this system provides high accessibility for microsurgical training. Copyright © 2017 Elsevier Inc. All rights reserved.

Determination of HCME 3-D parameters using a full ice-cream cone model

Science.gov (United States)

Na, Hyeonock; Moon, Yong-Jae; Lee, Harim

2016-05-01

It is very essential to determine three dimensional parameters (e.g., radial speed, angular width, source location) of Coronal Mass Ejections (CMEs) for space weather forecast. Several cone models (e.g., an elliptical cone model, an ice-cream cone model, an asymmetric cone model) have been examined to estimate these parameters. In this study, we investigate which cone type is close to a halo CME morphology using 26 CMEs: halo CMEs by one spacecraft (SOHO or STEREO-A or B) and as limb CMEs by the other ones. From cone shape parameters of these CMEs such as their front curvature, we find that near full ice-cream cone type CMEs are much closer to observations than shallow ice-cream cone type CMEs. Thus we develop a new cone model in which a full ice-cream cone consists of many flat cones with different heights and angular widths. This model is carried out by the following steps: (1) construct a cone for given height and angular width, (2) project the cone onto the sky plane, (3) select points comprising the outer boundary, and (4) minimize the difference between the estimated projection speeds with the observed ones. By applying this model to 12 SOHO/LASCO halo CMEs, we find that 3-D parameters from our method are similar to those from other stereoscopic methods (a geometrical triangulation method and a Graduated Cylindrical Shell model) based on multi-spacecraft data. We are developing a general ice-cream cone model whose front shape is a free parameter determined by observations.

Impact of floating windows on the accuracy of depth perception in games

Science.gov (United States)

Stanfield, Brodie; Zerebecki, Christopher; Hogue, Andrew; Kapralos, Bill; Collins, Karen

2013-03-01

The floating window technique is commonly employed by stereoscopic 3D filmmakers to reduce the effects of window violations by masking out portions of the screen that contain visual information that doesn't exist in one of the views. Although widely adopted in the film industry, and despite its potential benefits, the technique has not been adopted by video game developers to the same extent possibly because of the lack of understanding of how the floating window can be utilized in such an interactive medium. Here, we describe a quantitative study that investigates how the floating window technique affects users' depth perception in a simple game-like environment. Our goal is to determine how various stereoscopic 3D parameters such as the existence, shape, and size of the floating window affect the user experience and to devise a set of guidelines for game developers wishing to develop stereoscopic 3D content. Providing game designers with quantitative knowledge of how these parameters can affect user experience is invaluable when choosing to design interactive stereoscopic 3D content.

Morphometric Optic Nerve Head Analysis in Glaucoma Patients: A Comparison between the Simultaneous Nonmydriatic Stereoscopic Fundus Camera (Kowa Nonmyd WX3D and the Heidelberg Scanning Laser Ophthalmoscope (HRT III

Directory of Open Access Journals (Sweden)

Siegfried Mariacher

2016-01-01

Full Text Available Purpose. To investigate the agreement between morphometric optic nerve head parameters assessed with the confocal laser ophthalmoscope HRT III and the stereoscopic fundus camera Kowa nonmyd WX3D retrospectively. Methods. Morphometric optic nerve head parameters of 40 eyes of 40 patients with primary open angle glaucoma were analyzed regarding their vertical cup-to-disc-ratio (CDR. Vertical CDR, disc area, cup volume, rim volume, and maximum cup depth were assessed with both devices by one examiner. Mean bias and limits of agreement (95% CI were obtained using scatter plots and Bland-Altman analysis. Results. Overall vertical CDR comparison between HRT III and Kowa nonmyd WX3D measurements showed a mean difference (limits of agreement of −0.06 (−0.36 to 0.24. For the CDR < 0.5 group (n=24 mean difference in vertical CDR was −0.14 (−0.34 to 0.06 and for the CDR ≥ 0.5 group (n=16 0.06 (−0.21 to 0.34. Conclusion. This study showed a good agreement between Kowa nonmyd WX3D and HRT III with regard to widely used optic nerve head parameters in patients with glaucomatous optic neuropathy. However, data from Kowa nonmyd WX3D exhibited the tendency to measure larger CDR values than HRT III in the group with CDR < 0.5 group and lower CDR values in the group with CDR ≥ 0.5.

Optimal control of set-up margins and internal margins for intra and extracranial radiotherapy using stereoscopic kilo voltage imaging; Controle optimal des incertitudes de positionnement externes et internes lors d'irradiations craniennes et extracraniennes par imagerie stereoscopique de basse energie

Energy Technology Data Exchange (ETDEWEB)

Verellen, D.; Soete, G.; Linthout, N.; Tournel, K.; Storme, G. [Vrije Universiteit Brussel (AZ-VUB), Dept. of Radiotherapy, Oncology Center, Academic Hospital, Brussels (Belgium)

2006-09-15

In this paper the clinical introduction of stereoscopic kV-imaging in combination with a 6 degrees-of-freedom (6 DOF) robotics system and breathing synchronized irradiation will be discussed in view of optimally reducing inter-fractional as well as intra-fractional geometric uncertainties in conformal radiation therapy. Extracranial cases represent approximately 70% of the patient population on the NOVALIS treatment machine (BrainLAB A.G., Germany) at the AZ-VUB, which is largely due to the efficiency of the real-time positioning features of the kV-imaging system. The prostate case will be used as an example of those target volumes showing considerable changes in position from day-to-day, yet with negligible motion during the actual course of the treatment. As such it will be used to illustrate the on-line target localization using kV-imaging and 6 DOF patient adjustment with and without implanted radio-opaque markers prior to treatment. Small lung lesion will be used to illustrate the system's potential to synchronize the irradiation with breathing in coping with intra-fractional organ motion. (authors)

Determination of CME 3D parameters based on a new full ice-cream cone model

Science.gov (United States)

Na, Hyeonock; Moon, Yong-Jae

2017-08-01

In space weather forecast, it is important to determine three-dimensional properties of CMEs. Using 29 limb CMEs, we examine which cone type is close to a CME three-dimensional structure. We find that most CMEs have near full ice-cream cone structure which is a symmetrical circular cone combined with a hemisphere. We develop a full ice-cream cone model based on a new methodology that the full ice-cream cone consists of many flat cones with different heights and angular widths. By applying this model to 12 SOHO/LASCO halo CMEs, we find that 3D parameters from our method are similar to those from other stereoscopic methods (i.e., a triangulation method and a Graduated Cylindrical Shell model). In addition, we derive CME mean density (ρmean=Mtotal/Vcone) based on the full ice-cream cone structure. For several limb events, we determine CME mass by applying the Solarsoft procedure (e.g., cme_mass.pro) to SOHO/LASCO C3 images. CME volumes are estimated from the full ice-cream cone structure. From the power-law relationship between CME mean density and its height, we estimate CME mean densities at 20 solar radii (Rs). We will compare the CME densities at 20 Rs with their corresponding ICME densities.

3D gaze tracking system for NVidia 3D Vision®.

Science.gov (United States)

Wibirama, Sunu; Hamamoto, Kazuhiko

2013-01-01

Inappropriate parallax setting in stereoscopic content generally causes visual fatigue and visual discomfort. To optimize three dimensional (3D) effects in stereoscopic content by taking into account health issue, understanding how user gazes at 3D direction in virtual space is currently an important research topic. In this paper, we report the study of developing a novel 3D gaze tracking system for Nvidia 3D Vision(®) to be used in desktop stereoscopic display. We suggest an optimized geometric method to accurately measure the position of virtual 3D object. Our experimental result shows that the proposed system achieved better accuracy compared to conventional geometric method by average errors 0.83 cm, 0.87 cm, and 1.06 cm in X, Y, and Z dimensions, respectively.

Stereosat: A proposed private sector/government joint venture in remote sensing from space

Science.gov (United States)

Anglin, R. L.

1980-01-01

Stereosat, a free flying Sun synchronous satellite whose purpose is to obtain worldwide cloud-free stereoscopic images of the Earth's land masses, is proposed as a joint private sector/government venture. A number of potential organization models are identified. The legal, economic, and institutional issues which could impact the continuum of potential joint private sector/government institutional structures are examined.

3D moviemap and a 3D panorama

Science.gov (United States)

Naimark, Michael

1997-05-01

Two immersive virtual environments produced as art installations investigate 'sense of place' in different but complimentary ways. One is a stereoscopic moviemap, the other a stereoscopic panorama. Moviemaps are interactive systems which allow 'travel' along pre-recorded routes with some control over speed and direction. Panoramas are 360 degree visual representations dating back to the late 18th century but which have recently experienced renewed interest due to 'virtual reality' systems. Moviemaps allow 'moving around' while panoramas allow 'looking around,' but to date there has been little or no attempt to produce either in stereo from camera-based material. 'See Banff stereoscopic moviemap about landscape, tourism, and growth in the Canadian Rocky Mountains. It was filmed with twin 16 mm cameras and displayed as a single-user experience housed in a cabinet resembling a century-old kinetoscope, with a crank on the side for 'moving through' the material. 'Be Now Here (Welcome to the Neighborhood)' (1995-6) is a stereoscopic panorama filmed in public gathering places around the world, based upon the UNESCO World Heritage 'In Danger' list. It was filmed with twin 35 mm motion picture cameras on a rotating tripod and displayed using a synchronized rotating floor.

Intubation simulation with a cross-sectional visual guidance.

Science.gov (United States)

Rhee, Chi-Hyoung; Kang, Chul Won; Lee, Chang Ha

2013-01-01

We present an intubation simulation with deformable objects and a cross-sectional visual guidance using a general haptic device. Our method deforms the tube model when it collides with the human model. Mass-Spring model with the Euler integration is used for the tube deformation. For the trainee's more effective understanding of the intubation process, we provide a cross-sectional view of the oral cavity and the tube. Our system also applies a stereoscopic rendering to improve the depth perception and the reality of the simulation.

Fisheye-Based Method for GPS Localization Improvement in Unknown Semi-Obstructed Areas

Directory of Open Access Journals (Sweden)

Julien Moreau

2017-01-01

Full Text Available A precise GNSS (Global Navigation Satellite System localization is vital for autonomous road vehicles, especially in cluttered or urban environments where satellites are occluded, preventing accurate positioning. We propose to fuse GPS (Global Positioning System data with fisheye stereovision to face this problem independently to additional data, possibly outdated, unavailable, and needing correlation with reality. Our stereoscope is sky-facing with 360° × 180° fisheye cameras to observe surrounding obstacles. We propose a 3D modelling and plane extraction through following steps: stereoscope self-calibration for decalibration robustness, stereo matching considering neighbours epipolar curves to compute 3D, and robust plane fitting based on generated cartography and Hough transform. We use these 3D data with GPS raw data to estimate NLOS (Non Line Of Sight reflected signals pseudorange delay. We exploit extracted planes to build a visibility mask for NLOS detection. A simplified 3D canyon model allows to compute reflections pseudorange delays. In the end, GPS positioning is computed considering corrected pseudoranges. With experimentations on real fixed scenes, we show generated 3D models reaching metric accuracy and improvement of horizontal GPS positioning accuracy by more than 50%. The proposed procedure is effective, and the proposed NLOS detection outperforms CN0-based methods (Carrier-to-receiver Noise density.

A novel 360-degree shape measurement using a simple setup with two mirrors and a laser MEMS scanner

Science.gov (United States)

Jin, Rui; Zhou, Xiang; Yang, Tao; Li, Dong; Wang, Chao

2017-09-01

There is no denying that 360-degree shape measurement technology plays an important role in the field of threedimensional optical metrology. Traditional optical 360-degree shape measurement methods are mainly two kinds: the first kind, by placing multiple scanners to achieve 360-degree measurements; the second kind, through the high-precision rotating device to get 360-degree shape model. The former increases the number of scanners and costly, while the latter using rotating devices lead to time consuming. This paper presents a low cost and fast optical 360-degree shape measurement method, which possesses the advantages of full static, fast and low cost. The measuring system consists of two mirrors with a certain angle, a laser projection system, a stereoscopic calibration block, and two cameras. And most of all, laser MEMS scanner can achieve precise movement of laser stripes without any movement mechanism, improving the measurement accuracy and efficiency. What's more, a novel stereo calibration technology presented in this paper can achieve point clouds data registration, and then get the 360-degree model of objects. A stereoscopic calibration block with special coded patterns on six sides is used in this novel stereo calibration method. Through this novel stereo calibration technology we can quickly get the 360-degree models of objects.

The effects of video game experience and active stereoscopy on performance in combat identification tasks.

Science.gov (United States)

Keebler, Joseph R; Jentsch, Florian; Schuster, David

2014-12-01

We investigated the effects of active stereoscopic simulation-based training and individual differences in video game experience on multiple indices of combat identification (CID) performance. Fratricide is a major problem in combat operations involving military vehicles. In this research, we aimed to evaluate the effects of training on CID performance in order to reduce fratricide errors. Individuals were trained on 12 combat vehicles in a simulation, which were presented via either a non-stereoscopic or active stereoscopic display using NVIDIA's GeForce shutter glass technology. Self-report was used to assess video game experience, leading to four between-subjects groups: high video game experience with stereoscopy, low video game experience with stereoscopy, high video game experience without stereoscopy, and low video game experience without stereoscopy. We then tested participants on their memory of each vehicle's alliance and name across multiple measures, including photographs and videos. There was a main effect for both video game experience and stereoscopy across many of the dependent measures. Further, we found interactions between video game experience and stereoscopic training, such that those individuals with high video game experience in the non-stereoscopic group had the highest performance outcomes in the sample on multiple dependent measures. This study suggests that individual differences in video game experience may be predictive of enhanced performance in CID tasks. Selection based on video game experience in CID tasks may be a useful strategy for future military training. Future research should investigate the generalizability of these effects, such as identification through unmanned vehicle sensors.

3D Visualization of Trees Based on a Sphere-Board Model

Directory of Open Access Journals (Sweden)

Jiangfeng She

2018-01-01

Full Text Available Because of the smooth interaction of tree systems, the billboard and crossed-plane techniques of image-based rendering (IBR have been used for tree visualization for many years. However, both the billboard-based tree model (BBTM and the crossed-plane tree model (CPTM have several notable limitations; for example, they give an impression of slicing when viewed from the top side, and they produce an unimpressive stereoscopic effect and insufficient lighted effects. In this study, a sphere-board-based tree model (SBTM is proposed to eliminate these defects and to improve the final visual effects. Compared with the BBTM or CPTM, the proposed SBTM uses one or more sphere-like 3D geometric surfaces covered with a virtual texture, which can present more details about the foliage than can 2D planes, to represent the 3D outline of a tree crown. However, the profile edge presented by a continuous surface is overly smooth and regular, and when used to delineate the outline of a tree crown, it makes the tree appear very unrealistic. To overcome this shortcoming and achieve a more natural final visual effect of the tree model, an additional process is applied to the edge of the surface profile. In addition, the SBTM can better support lighted effects because of its cubic geometrical features. Interactive visualization effects for a single tree and a grove are presented in a case study of Sabina chinensis. The results show that the SBTM can achieve a better compromise between realism and performance than can the BBTM or CPTM.

Accommodation training in foreign workers.

Science.gov (United States)

Takada, Masumi; Miyao, Masaru; Matsuura, Yasuyuki; Takada, Hiroki

2013-01-01

By relaxing the contracted focus-adjustment muscles around the eyeball, known as the ciliary and extraocular muscles, the degree of pseudomyopia can be reduced. This understanding has led to accommodation training in which a visual target is presented in stereoscopic video clips. However, it has been pointed out that motion sickness can be induced by viewing stereoscopic video clips. In Measurement 1 of the present study, we verified whether the new 3D technology reduced the severity of motion sickness in accordance with stabilometry. We then evaluated the short-term effects of accommodation training using new stereoscopic video clips on foreign workers (11 females) suffering from eye fatigue in Measurement 2. The foreign workers were trained for three days. As a result, visual acuity was statistically improved by continuous accommodation training, which will help promote ciliary muscle stretching.

Reducing Visual Discomfort with HMDs Using Dynamic Depth of Field.

Science.gov (United States)

Carnegie, Kieran; Rhee, Taehyun

2015-01-01

Although head-mounted displays (HMDs) are ideal devices for personal viewing of immersive stereoscopic content, exposure to VR applications on them results in significant discomfort for the majority of people, with symptoms including eye fatigue, headaches, nausea, and sweating. A conflict between accommodation and vergence depth cues on stereoscopic displays is a significant cause of visual discomfort. This article describes the results of an evaluation used to judge the effectiveness of dynamic depth-of-field (DoF) blur in an effort to reduce discomfort caused by exposure to stereoscopic content on HMDs. Using a commercial game engine implementation, study participants report a reduction of visual discomfort on a simulator sickness questionnaire when DoF blurring is enabled. The study participants reported a decrease in symptom severity caused by HMD exposure, indicating that dynamic DoF can effectively reduce visual discomfort.

Three-Dimensional Dynamic Deformation Measurements Using Stereoscopic Imaging and Digital Speckle Photography

International Nuclear Information System (INIS)

Prentice, H. J.; Proud, W. G.

2006-01-01

A technique has been developed to determine experimentally the three-dimensional displacement field on the rear surface of a dynamically deforming plate. The technique combines speckle analysis with stereoscopy, using a modified angular-lens method: this incorporates split-frame photography and a simple method by which the effective lens separation can be adjusted and calibrated in situ. Whilst several analytical models exist to predict deformation in extended or semi-infinite targets, the non-trivial nature of the wave interactions complicates the generation and development of analytical models for targets of finite depth. By interrogating specimens experimentally to acquire three-dimensional strain data points, both analytical and numerical model predictions can be verified more rigorously. The technique is applied to the quasi-static deformation of a rubber sheet and dynamically to Mild Steel sheets of various thicknesses

Stereo Viewing System. Innovative Technology Summary Report

International Nuclear Information System (INIS)

None

2000-01-01

The Stereo Viewing System provides stereoscopic viewing of Light Duty Utility Arm activities. Stereoscopic viewing allows operators to see the depth of objects. This capability improves the control of the Light Duty Utility Arm performed in DOE's underground radioactive waste storage tanks and allows operators to evaluate the depth of pits, seams, and other anomalies. Potential applications include Light Duty Utility Arm deployment operations at the Oak Ridge Reservation, Hanford Site, and the Idaho National Engineering and Environmental Laboratory

Storage, access, and retrieval of endoscopic and laparoscopic video

Science.gov (United States)

Bellaire, Gunter; Steines, Daniel; Graschew, Georgi; Thiel, Andreas; Bernarding, Johannes; Tolxdorff, Thomas; Schlag, Peter M.

1999-05-01

The system presented here enhances documentation and data- secured, second-opinion facilities by integrating video into DICOM3.0. Digital stereoscopic video sequences (DSVS) are especially in demand for surgery (laparoscopy, microsurgery, surgical microscopy, second opinion, virtual reality). Therefore DSVS are also integrated into the DICOM video concept. We present an implementation for a medical video server extended by a DICOM interface. Security mechanisms conforming with DICOM are integrated to enable secure internet access. Digital (stereoscopic) video sequences relevant for surgery should be examined regarding the clip length necessary for diagnosis and documentation and the clip size manageable with today's hardware. Methods for DSVS compression are described, implemented, and tested. Image sources relevant for this paper include, among others, a stereoscopic laparoscope and a monoscopic endoscope. Additionally, an approach is presented to analyze the motion of the endoscopic camera for future automatic video- cutting.

Recovering stereo vision by squashing virtual bugs in a virtual reality environment.

Science.gov (United States)

Vedamurthy, Indu; Knill, David C; Huang, Samuel J; Yung, Amanda; Ding, Jian; Kwon, Oh-Sang; Bavelier, Daphne; Levi, Dennis M

2016-06-19

Stereopsis is the rich impression of three-dimensionality, based on binocular disparity-the differences between the two retinal images of the same world. However, a substantial proportion of the population is stereo-deficient, and relies mostly on monocular cues to judge the relative depth or distance of objects in the environment. Here we trained adults who were stereo blind or stereo-deficient owing to strabismus and/or amblyopia in a natural visuomotor task-a 'bug squashing' game-in a virtual reality environment. The subjects' task was to squash a virtual dichoptic bug on a slanted surface, by hitting it with a physical cylinder they held in their hand. The perceived surface slant was determined by monocular texture and stereoscopic cues, with these cues being either consistent or in conflict, allowing us to track the relative weighting of monocular versus stereoscopic cues as training in the task progressed. Following training most participants showed greater reliance on stereoscopic cues, reduced suppression and improved stereoacuity. Importantly, the training-induced changes in relative stereo weights were significant predictors of the improvements in stereoacuity. We conclude that some adults deprived of normal binocular vision and insensitive to the disparity information can, with appropriate experience, recover access to more reliable stereoscopic information.This article is part of the themed issue 'Vision in our three-dimensional world'. © 2016 The Author(s).

Recovering stereo vision by squashing virtual bugs in a virtual reality environment

Science.gov (United States)

Vedamurthy, Indu; Knill, David C.; Huang, Samuel J.; Yung, Amanda; Ding, Jian; Kwon, Oh-Sang; Bavelier, Daphne

2016-01-01

Stereopsis is the rich impression of three-dimensionality, based on binocular disparity—the differences between the two retinal images of the same world. However, a substantial proportion of the population is stereo-deficient, and relies mostly on monocular cues to judge the relative depth or distance of objects in the environment. Here we trained adults who were stereo blind or stereo-deficient owing to strabismus and/or amblyopia in a natural visuomotor task—a ‘bug squashing’ game—in a virtual reality environment. The subjects' task was to squash a virtual dichoptic bug on a slanted surface, by hitting it with a physical cylinder they held in their hand. The perceived surface slant was determined by monocular texture and stereoscopic cues, with these cues being either consistent or in conflict, allowing us to track the relative weighting of monocular versus stereoscopic cues as training in the task progressed. Following training most participants showed greater reliance on stereoscopic cues, reduced suppression and improved stereoacuity. Importantly, the training-induced changes in relative stereo weights were significant predictors of the improvements in stereoacuity. We conclude that some adults deprived of normal binocular vision and insensitive to the disparity information can, with appropriate experience, recover access to more reliable stereoscopic information. This article is part of the themed issue ‘Vision in our three-dimensional world’. PMID:27269607

Status of the MAGIC telescopes

Energy Technology Data Exchange (ETDEWEB)

Colin, Pierre; Carmona, Emiliano; Schweizer, Thomas; Sitarek, Julian [Max-Planck-Institut fuer Physik, Werner-Heisenberg Institut, Muenchen (Germany)

2010-07-01

MAGIC is a system of two 17-m Cherenkov telescopes located on La Palma (Canary islands),sensitive to gamma-rays above 30 GeV. It has been recently upgraded by a second telescope which strongly improves the sensitivity, particularly at low energy. Here we present the status of the MAGIC telescopes and an overview of the recent results obtained in single or stereoscopic mode. We also discuss the real performance of the new stereoscopic system based on Crab Nebula observations.

可搬型PIVシステムの遷音速風洞への適用

OpenAIRE

Kato, Hiroyuki; Watanabe, Shigeya; Karasawa, Toshio; Noguchi, Masayoshi; Hashimoto, Takuro; Yoshimura, Sadanori; 加藤　裕之; 渡辺　重哉; 唐沢　敏夫; 野口　正芳; 橋本　拓郎; 吉村　定修

2006-01-01

Stereoscopic PIV technique was applied to the JAXA next-generation supersonic transport (SST) jet experimental airplane model. The measurements have been performed in the JAXA 2 m x 2 m Transonic Wind Tunnel. Application of PIV measurement techniques to transonic wind tunnels has particular difficulties associated with complex flows with shock waves. Due to these difficulties, practical experiments of PIV measurements in transonic wind tunnels are limited. In the present study, a fully remote...

Development of a Full Ice-cream Cone Model for Halo Coronal Mass Ejections

Energy Technology Data Exchange (ETDEWEB)

Na, Hyeonock; Moon, Y.-J.; Lee, Harim, E-mail: nho0512@khu.ac.kr, E-mail: moonyj@khu.ac.kr [School of Space Research, Kyung Hee University, Yongin (Korea, Republic of)

2017-04-20

It is essential to determine three-dimensional parameters (e.g., radial speed, angular width, and source location) of coronal mass ejections (CMEs) for the space weather forecast. In this study, we investigate which cone type represents a halo CME morphology using 29 CMEs (12 Solar and Heliospheric Observatory (SOHO) /Large Angle and Spectrometric Coronagraph (LASCO) halo CMEs and 17 Solar Terrestrial Relations Observatory ( STEREO )/Sun–Earth Connection Coronal and Heliospheric Investigation COR2 halo CMEs) from 2010 December to 2011 June. These CMEs are identified as halo CMEs by one spacecraft ( SOHO or one of STEREO A and B ) and limb ones by the other spacecraft (One of STEREO A and B or SOHO ). From cone shape parameters of these CMEs, such as their front curvature, we find that the CME observational structures are much closer to a full ice-cream cone type than a shallow ice-cream cone type. Thus, we develop a full ice-cream cone model based on a new methodology that the full ice-cream cone consists of many flat cones with different heights and angular widths to estimate the three-dimensional parameters of the halo CMEs. This model is constructed by carrying out the following steps: (1) construct a cone for a given height and angular width, (2) project the cone onto the sky plane, (3) select points comprising the outer boundary, and (4) minimize the difference between the estimated projection speeds with the observed ones. By applying this model to 12 SOHO /LASCO halo CMEs, we find that 3D parameters from our method are similar to those from other stereoscopic methods (i.e., a triangulation method and a Graduated Cylindrical Shell model).

Development of a Full Ice-cream Cone Model for Halo Coronal Mass Ejections

International Nuclear Information System (INIS)

Na, Hyeonock; Moon, Y.-J.; Lee, Harim

2017-01-01

It is essential to determine three-dimensional parameters (e.g., radial speed, angular width, and source location) of coronal mass ejections (CMEs) for the space weather forecast. In this study, we investigate which cone type represents a halo CME morphology using 29 CMEs (12 Solar and Heliospheric Observatory (SOHO) /Large Angle and Spectrometric Coronagraph (LASCO) halo CMEs and 17 Solar Terrestrial Relations Observatory ( STEREO )/Sun–Earth Connection Coronal and Heliospheric Investigation COR2 halo CMEs) from 2010 December to 2011 June. These CMEs are identified as halo CMEs by one spacecraft ( SOHO or one of STEREO A and B ) and limb ones by the other spacecraft (One of STEREO A and B or SOHO ). From cone shape parameters of these CMEs, such as their front curvature, we find that the CME observational structures are much closer to a full ice-cream cone type than a shallow ice-cream cone type. Thus, we develop a full ice-cream cone model based on a new methodology that the full ice-cream cone consists of many flat cones with different heights and angular widths to estimate the three-dimensional parameters of the halo CMEs. This model is constructed by carrying out the following steps: (1) construct a cone for a given height and angular width, (2) project the cone onto the sky plane, (3) select points comprising the outer boundary, and (4) minimize the difference between the estimated projection speeds with the observed ones. By applying this model to 12 SOHO /LASCO halo CMEs, we find that 3D parameters from our method are similar to those from other stereoscopic methods (i.e., a triangulation method and a Graduated Cylindrical Shell model).

Development of a Full Ice-cream Cone Model for Halo Coronal Mass Ejections

Science.gov (United States)

Na, Hyeonock; Moon, Y.-J.; Lee, Harim

2017-04-01

It is essential to determine three-dimensional parameters (e.g., radial speed, angular width, and source location) of coronal mass ejections (CMEs) for the space weather forecast. In this study, we investigate which cone type represents a halo CME morphology using 29 CMEs (12 Solar and Heliospheric Observatory (SOHO)/Large Angle and Spectrometric Coronagraph (LASCO) halo CMEs and 17 Solar Terrestrial Relations Observatory (STEREO)/Sun-Earth Connection Coronal and Heliospheric Investigation COR2 halo CMEs) from 2010 December to 2011 June. These CMEs are identified as halo CMEs by one spacecraft (SOHO or one of STEREO A and B) and limb ones by the other spacecraft (One of STEREO A and B or SOHO). From cone shape parameters of these CMEs, such as their front curvature, we find that the CME observational structures are much closer to a full ice-cream cone type than a shallow ice-cream cone type. Thus, we develop a full ice-cream cone model based on a new methodology that the full ice-cream cone consists of many flat cones with different heights and angular widths to estimate the three-dimensional parameters of the halo CMEs. This model is constructed by carrying out the following steps: (1) construct a cone for a given height and angular width, (2) project the cone onto the sky plane, (3) select points comprising the outer boundary, and (4) minimize the difference between the estimated projection speeds with the observed ones. By applying this model to 12 SOHO/LASCO halo CMEs, we find that 3D parameters from our method are similar to those from other stereoscopic methods (I.e., a triangulation method and a Graduated Cylindrical Shell model).

Virtual reality and stereoscopic telepresence

International Nuclear Information System (INIS)

Mertens, E.P.

1994-12-01

Virtual reality technology is commonly thought to have few, if any, applications beyond the national research laboratories, the aerospace industry, and the entertainment world. A team at Westinghouse Hanford Company (WHC) is developing applications for virtual reality technology that make it a practical, viable, portable, and cost-effective business and training tool. The technology transfer is particularly applicable to the waste management industry and has become a tool that can serve the entire work force spectrum, from industrial sites to business offices. For three and a half years, a small team of WHC personnel has been developing an effective and practical method of bringing virtual reality technology to the job site. The applications are practical, the results are repeatable, and the equipment costs are within the range of present-day office machines. That combination can evolve into a competitive advantage for commercial business interests. The WHC team has contained system costs by using commercially available equipment and personal computers to create effective virtual reality work stations for less than $20,000

SU-E-J-39: Comparison of PTV Margins Determined by In-Room Stereoscopic Image Guidance and by On-Board Cone Beam Computed Tomography Technique for Brain Radiotherapy Patients

International Nuclear Information System (INIS)

Ganesh, T; Paul, S; Munshi, A; Sarkar, B; Krishnankutty, S; Sathya, J; George, S; Jassal, K; Roy, S; Mohanti, B

2014-01-01

Purpose: Stereoscopic in room kV image guidance is a faster tool in daily monitoring of patient positioning. Our centre, for the first time in the world, has integrated such a solution from BrainLAB (ExacTrac) with Elekta's volumetric cone beam computed tomography (XVI). Using van Herk's formula, we compared the planning target volume (PTV) margins calculated by both these systems for patients treated with brain radiotherapy. Methods: For a total of 24 patients who received partial or whole brain radiotherapy, verification images were acquired for 524 treatment sessions by XVI and for 334 sessions by ExacTrac out of the total 547 sessions. Systematic and random errors were calculated in cranio-caudal, lateral and antero-posterior directions for both techniques. PTV margins were then determined using van Herk formula. Results: In the cranio-caudal direction, systematic error, random error and the calculated PTV margin were found to be 0.13 cm, 0.12 cm and 0.41 cm with XVI and 0.14 cm, 0.13 cm and 0.44 cm with ExacTrac. The corresponding values in lateral direction were 0.13 cm 0.1 cm and 0.4 cm with XVI and 0.13 cm, 0.12 cm and 0.42 cm with ExacTrac imaging. The same parameters for antero-posterior were for 0.1 cm, 0.11 cm and 0.34 cm with XVI and 0.13 cm, 0.16 cm and 0.43 cm with ExacTrac imaging. The margins estimated with the two imaging modalities were comparable within ± 1 mm limit. Conclusion: Verification of setup errors in the major axes by two independent imaging systems showed the results are comparable and within ± 1 mm. This implies that planar imaging based ExacTrac can yield equal accuracy in setup error determination as the time consuming volumetric imaging which is considered as the gold standard. Accordingly PTV margins estimated by this faster imaging technique can be confidently used in clinical setup

2D Versus 3D: The Relevance of the Mode of Presentation for the Economic Valuation of an Alpine Landscape

Directory of Open Access Journals (Sweden)

Michael Getzner

2016-06-01

Full Text Available In order to value the transformation of landscapes from an economic perspective, survey respondents are usually presented with pictures of various landscapes with the aim to visualize differences in their appearance. The current paper presents a classroom experiment ascertaining differences, and potential advantages and disadvantages, of 2D versus 3D (stereoscopic presentations of landscape changes. The landscape to be valued was a traditional Alpine pasture in the Austrian Alps as a prominent example of natural and cultural heritage (traditional economy and specific ecology. Two alternative scenarios included, on the one hand, changes in agricultural uses, leading to natural afforestation (reforestation and decay of existing infrastructure (e.g., hiking trails. On the other hand, significantly extended tourism infrastructure (e.g., new attractions for visitors was presented. Two groups were presented manipulated pictures (2D/non-stereoscopic, and 3D (stereoscopic presentations with 3D glasses, respectively. Both groups were then asked for their perception of landscape changes. It turns out that significant differences between the two groups could be detected in terms of the frequency of vacations at Alpine pastures. For instance, respondents in the 3D stereoscopic group stated a significantly higher frequency of trips. However, on the other hand, they did not state a significantly different willingness-to-pay to prevent landscape changes disadvantageous in terms of sustainability. The study results thus suggest that the mode of presentation may affect the valuation of landscape changes depending on the valuation instrument.

Indoor calibration for stereoscopic camera STC: a new method

Science.gov (United States)

Simioni, E.; Re, C.; Da Deppo, V.; Naletto, G.; Borrelli, D.; Dami, M.; Ficai Veltroni, I.; Cremonese, G.

2017-11-01

In the framework of the ESA-JAXA BepiColombo mission to Mercury, the global mapping of the planet will be performed by the on-board Stereo Camera (STC), part of the SIMBIO-SYS suite [1]. In this paper we propose a new technique for the validation of the 3D reconstruction of planetary surface from images acquired with a stereo camera. STC will provide a three-dimensional reconstruction of Mercury surface. The generation of a DTM of the observed features is based on the processing of the acquired images and on the knowledge of the intrinsic and extrinsic parameters of the optical system. The new stereo concept developed for STC needs a pre-flight verification of the actual capabilities to obtain elevation information from stereo couples: for this, a stereo validation setup to get an indoor reproduction of the flight observing condition of the instrument would give a much greater confidence to the developed instrument design. STC is the first stereo satellite camera with two optical channels converging in a unique sensor. Its optical model is based on a brand new concept to minimize mass and volume and to allow push-frame imaging. This model imposed to define a new calibration pipeline to test the reconstruction method in a controlled ambient. An ad-hoc indoor set-up has been realized for validating the instrument designed to operate in deep space, i.e. in-flight STC will have to deal with source/target essentially placed at infinity. This auxiliary indoor setup permits on one side to rescale the stereo reconstruction problem from the operative distance in-flight of 400 km to almost 1 meter in lab; on the other side it allows to replicate different viewing angles for the considered targets. Neglecting for sake of simplicity the Mercury curvature, the STC observing geometry of the same portion of the planet surface at periherm corresponds to a rotation of the spacecraft (SC) around the observed target by twice the 20° separation of each channel with respect to nadir

Protection of Embossed Holograms by Computer Animation

Directory of Open Access Journals (Sweden)

Werner Sobotka

2000-08-01

Full Text Available Digital imaging in connection with computer animation is optimizing the counterfeiting security. All preparation work can be done outside the holographic lab and therefore an easier control process for the client is possible. The paper is dealing with a new holographic imaging process using computer animation and combining the results with the holographic stereoscopic technique. The paper is dealing with the holographic mastering and also with the construction of the holographic environment for special stereoscopic holographic imaging techniques. A prototype for producing monochromatic holographic stereograms was developed.

[Rehabilitation by hollow obturator prosthesis immediately after total maxillectomy for malignant tumor].

Science.gov (United States)

Li, Xiao-ye; Yan, Ai-hui; Hao, Shuai; Li, Wei; Jiang, Xue-jun; Lu, Li; Qin, Xing-jun; Yan, Hai-xin

2011-05-01

The feasibility and clinical effects of hollow obturator prosthesis for the repair of maxillofacial defect immediately after maxillectomy for cancer were assessed. Thirteen patients with T3-4aN0M0 maxillary neoplasm were treated by the prostheses immediately after maxillectomy. According to the 3D-CT reconstruction of nasal sinus, the 3D stereoscopic prototype was constructed before the surgery. Simulating surgery with Surgicare 5.0 software and then the prosthesis 3D stereoscopic model was shaped. The prosthesis was made quickly and precisely with methacrylate resins according to the model and the print mold before surgery, with supplementary tooth at the bottom of prosthesis. In the surgery, the prosthesis was installed instantly after maxillectomy. The patients were followed up at 1, 3 and 6 month after the surgery, respectively. The facial features and the pronunciation clarity were examined and the questionnaires were carried out in the patients, with comparation by paired t-test. The hollow obturator prosthesis would be replaced by permanent prosthesis made of methacrylate resins at 6 month after the surgery. The hollow obturator prostheses were installed accurately and maxillofacial defects were repaired immediately after maxillectomy in the 13 patients. Postoperative follow-up showed there were significant differences in eyeball sagging (t = 4.67, P maxillectomy can improve survival quality of patient.

ANALYSIS OF THE PIT REMOVAL METHODS IN DIGITAL TERRAIN MODELS OF VARIOUS RESOLUTIONS

Directory of Open Access Journals (Sweden)

S. Šamanović

2016-06-01

Full Text Available Digital terrain model (DTM is the base for calculation of the surface runoff under the influence of the gravity (gravity flow in hydrological analysis. It is important to produce hydrologically corrected DTM with the removed natural and artificial depressions to avoid numerical problems in algorithms of the gravity flow. The pit removal procedure changes geomorphometry of the DTM. GIS software packages use pit removal algorithm independently of geomorphmetric features of the analyzed area. In need of minimally modified DTM after the pit removal areas, the carving method (deepen drainage routes and the filling method (fill sink were analyzed on three different geomorphometric areas (bare mountain range, hilly wooded area and the plain area intersected with the network of the drainage canals. The recommendation is given for the choice of geomorphometric least changing DTM algorithm. The input data are raster data of elevation points created by stereoscopic photogrammetry method in 5x5 and 25x25 meter resolution. Differences have been noticed during the process of creating raster data. The recommendation is given for the choice of the most acceptable method for each type of area on the basis of comparison of the original elevation points with the elevation points in created DTM.

Procedural training in virtual reality: A comparison of technology types

International Nuclear Information System (INIS)

Sebok, A.; Nystad, E.

2006-01-01

This paper describes a study investigating questions of learning effectiveness in different VR technology types. Four VR display technology types were compared in terms of their ability to support procedural learning. The VR systems included two desktop displays (mono-scopic and stereoscopic view), a large screen stereoscopic display, and a mono-scopic head-mounted display. Twenty-four participants completed procedural training scenarios on these different display types. Training effectiveness was assessed in terms of objective task performance. Following the training session, participants performed the procedure they had just learned using the same VR display type they used for training. Time to complete the procedure and errors were recorded. Retention and transfer of training were evaluated in a talk-through session 24 hours after the training. In addition, subjective questionnaire data were gathered to investigate perceived workload, Sense of Presence, simulator sickness, perceived usability, and ease of navigation. While no difference was found for the short-term learning, the study results indicate that retention and transfer of training were better supported by the large screen stereoscopic condition. (authors)

Interpolated sagittal and coronal reconstruction of CT images in the screening of neck abnormalities

International Nuclear Information System (INIS)

Koga, Issei

1983-01-01

Recontructed sagittal and coronal images were analyzed for their usefulness during clinical applications and to determine the correct use of recontruction techniques. Recontructed stereoscopic images can be formed by continuous or interrupted image reconstruction using interpolation. This study showed that lesions less than 10 mm in diameter should be made continuously and recontructed with uninterrupted technique. However, 5 mm interrupted distances are acceptable for interpolated reconstruction except in cases of lesions less than 10 mm in diameter. Clinically, interpolated reconstruction is not adequated for semicircular lesions less than 10 mm. Blood vessels and linear lesions are good condiated for the application of interpolated recontruction. Reconstruction of images using interrupted interpolation is therefore recommended for screening and for demonstrating correct stereoscopic information, except cases of small lesions less than 10 mm in diameter. Results of this study underscore the fact that obscure information in transverse CT images should be routinely utilized by interporating recontruction techniques, if transverse images are not made continuously. Interpolated recontruction may be helpful in obtaining stereoscopic information. (author)

JAXA2m×2m遷音速風洞におけるDLR F6模型のステレオPIV計測

OpenAIRE

Kato, Hiroyuki; Watanabe, Shigeya; Watanabe, Atsushi; 加藤, 裕之; 渡辺, 重哉; 塩原, 辰郎; 渡邉, 篤史

2009-01-01

Stereoscopic PIV technique was applied to the DLR F6 model. The measurements have been performed in the JAXA 2 m x 2 m Transonic Wind tunnel (JAXA TWT1). Application of PIV measurement techniques to transonic wind tunnels has particular difficulties associated with complex flows with shock waves. Due to these difficulties, practical experiments of PIV measurements in transonic wind tunnels are limited. In the present study, The wind tunnel tests were conducted in the cart #4 of JAXA TWT1 whic...

Solar stereoscopy – where are we and what developments do we require to progress?

Directory of Open Access Journals (Sweden)

T. Wiegelmann

2009-07-01

Full Text Available Observations from the two STEREO-spacecraft give us for the first time the possibility to use stereoscopic methods to reconstruct the 3-D solar corona. Classical stereoscopy works best for solid objects with clear edges. Consequently an application of classical stereoscopic methods to the faint structures visible in the optically thin coronal plasma is by no means straight forward and several problems have to be treated adequately: 1 First there is the problem of identifying one-dimensional structures – e.g. active region coronal loops or polar plumes- from the two individual EUV-images observed with STEREO/EUVI. 2 As a next step one has the association problem to find corresponding structures in both images. This becomes more difficult as the angle between STEREO-A and B increases. 3 Within the reconstruction problem stereoscopic methods are used to compute the 3-D-geometry of the identified structures. Without any prior assumptions, e.g., regarding the footpoints of coronal loops, the reconstruction problem has not one unique solution. 4 One has to estimate the reconstruction error or accuracy of the reconstructed 3-D-structure, which depends on the accuracy of the identified structures in 2-D, the separation angle between the spacecraft, but also on the location, e.g., for east-west directed coronal loops the reconstruction error is highest close to the loop top. 5 Eventually we are not only interested in the 3-D-geometry of loops or plumes, but also in physical parameters like density, temperature, plasma flow, magnetic field strength etc. Helpful for treating some of these problems are coronal magnetic field models extrapolated from photospheric measurements, because observed EUV-loops outline the magnetic field. This feature has been used for a new method dubbed "magnetic stereoscopy". As examples we show recent application to active region loops.

Automated detection of macular drusen using geometric background leveling and threshold selection.

Science.gov (United States)

Smith, R Theodore; Chan, Jackie K; Nagasaki, Takayuki; Ahmad, Umer F; Barbazetto, Irene; Sparrow, Janet; Figueroa, Marta; Merriam, Joanna

2005-02-01

Age-related macular degeneration (ARMD) is the most prevalent cause of visual loss in patients older than 60 years in the United States. Observation of drusen is the hallmark finding in the clinical evaluation of ARMD. To segment and quantify drusen found in patients with ARMD using image analysis and to compare the efficacy of image analysis segmentation with that of stereoscopic manual grading of drusen. Retrospective study. University referral center.Patients Photographs were randomly selected from an available database of patients with known ARMD in the ongoing Columbia University Macular Genetics Study. All patients were white and older than 60 years. Twenty images from 17 patients were selected as representative of common manifestations of drusen. Image preprocessing included automated color balancing and, where necessary, manual segmentation of confounding lesions such as geographic atrophy (3 images). The operator then chose among 3 automated processing options suggested by predominant drusen type. Automated processing consisted of elimination of background variability by a mathematical model and subsequent histogram-based threshold selection. A retinal specialist using a graphic tablet while viewing stereo pairs constructed digital drusen drawings for each image. The sensitivity and specificity of drusen segmentation using the automated method with respect to manual stereoscopic drusen drawings were calculated on a rigorous pixel-by-pixel basis. The median sensitivity and specificity of automated segmentation were 70% and 81%, respectively. After preprocessing and option choice, reproducibility of automated drusen segmentation was necessarily 100%. Automated drusen segmentation can be reliably performed on digital fundus photographs and result in successful quantification of drusen in a more precise manner than is traditionally possible with manual stereoscopic grading of drusen. With only minor preprocessing requirements, this automated detection

Nonlinear Force-free Coronal Magnetic Stereoscopy

Energy Technology Data Exchange (ETDEWEB)

Chifu, Iulia; Wiegelmann, Thomas; Inhester, Bernd, E-mail: chifu@mps.mpg.de [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

2017-03-01

Insights into the 3D structure of the solar coronal magnetic field have been obtained in the past by two completely different approaches. The first approach are nonlinear force-free field (NLFFF) extrapolations, which use photospheric vector magnetograms as boundary condition. The second approach uses stereoscopy of coronal magnetic loops observed in EUV coronal images from different vantage points. Both approaches have their strengths and weaknesses. Extrapolation methods are sensitive to noise and inconsistencies in the boundary data, and the accuracy of stereoscopy is affected by the ability of identifying the same structure in different images and by the separation angle between the view directions. As a consequence, for the same observational data, the 3D coronal magnetic fields computed with the two methods do not necessarily coincide. In an earlier work (Paper I) we extended our NLFFF optimization code by including stereoscopic constrains. The method was successfully tested with synthetic data, and within this work, we apply the newly developed code to a combined data set from SDO /HMI, SDO /AIA, and the two STEREO spacecraft. The extended method (called S-NLFFF) contains an additional term that monitors and minimizes the angle between the local magnetic field direction and the orientation of the 3D coronal loops reconstructed by stereoscopy. We find that when we prescribe the shape of the 3D stereoscopically reconstructed loops, the S-NLFFF method leads to a much better agreement between the modeled field and the stereoscopically reconstructed loops. We also find an appreciable decrease by a factor of two in the angle between the current and the magnetic field. This indicates the improved quality of the force-free solution obtained by S-NLFFF.

Experimental investigations of pupil accommodation factors.

Science.gov (United States)

Lee, Eui Chul; Lee, Ji Woo; Park, Kang Ryoung

2011-08-17

PURPOSE. The contraction and dilation of the iris muscle that controls the amount of light entering the retina causes pupil accommodation. In this study, experiments were performed and two of the three factors that influence pupil accommodation were analyzed: lighting conditions and depth fixations. The psychological benefits were not examined, because they could not be quantified. METHODS. A head-wearable eyeglasses-based, eye-capturing device was designed to measure pupil size. It included a near-infrared (NIR) camera and an NIR light-emitting diode. Twenty-four subjects watched two-dimensional (2D) and three-dimensional (3D) stereoscopic videos of the same content, and the changes in pupil size were measured by using the eye-capturing device and image-processing methods: RESULTS. The pupil size changed with the intensity of the videos and the disparities between the left and right images of a 3D stereoscopic video. There was correlation between the pupil size and average intensity. The pupil diameter could be estimated as being contracted from approximately 5.96 to 4.25 mm as the intensity varied from 0 to 255. Further, from the changes in the depth fixation for the pupil accommodation, it was confirmed that the depth fixation also affected accommodation of pupil size. CONCLUSIONS. It was confirmed that the lighting condition was an even more significant factor in pupil accommodation than was depth fixation (significance ratio: approximately 3.2:1) when watching 3D stereoscopic video. Pupil accommodation was more affected by depth fixation in the real world than was the binocular convergence in the 3D stereoscopic display.

Optimal combination of illusory and luminance-defined 3-D surfaces: A role for ambiguity.

Science.gov (United States)

Hartle, Brittney; Wilcox, Laurie M; Murray, Richard F

2018-04-01

The shape of the illusory surface in stereoscopic Kanizsa figures is determined by the interpolation of depth from the luminance edges of adjacent inducing elements. Despite ambiguity in the position of illusory boundaries, observers reliably perceive a coherent three-dimensional (3-D) surface. However, this ambiguity may contribute additional uncertainty to the depth percept beyond what is expected from measurement noise alone. We evaluated the intrinsic ambiguity of illusory boundaries by using a cue-combination paradigm to measure the reliability of depth percepts elicited by stereoscopic illusory surfaces. We assessed the accuracy and precision of depth percepts using 3-D Kanizsa figures relative to luminance-defined surfaces. The location of the surface peak was defined by illusory boundaries, luminance-defined edges, or both. Accuracy and precision were assessed using a depth-discrimination paradigm. A maximum likelihood linear cue combination model was used to evaluate the relative contribution of illusory and luminance-defined signals to the perceived depth of the combined surface. Our analysis showed that the standard deviation of depth estimates was consistent with an optimal cue combination model, but the points of subjective equality indicated that observers consistently underweighted the contribution of illusory boundaries. This systematic underweighting may reflect a combination rule that attributes additional intrinsic ambiguity to the location of the illusory boundary. Although previous studies show that illusory and luminance-defined contours share many perceptual similarities, our model suggests that ambiguity plays a larger role in the perceptual representation of illusory contours than of luminance-defined contours.

Stereoscopic measurements of particle dispersion in microgravity turbulent flow

Science.gov (United States)

Groszmann, Daniel Eduardo

2001-08-01

The presence of particles in turbulent flows adds complexity to an already difficult subject. The work described in this research dissertation was intended to characterize the effects of inertia, isolated from gravity, on the dispersion of solid particles in a turbulent air flow. The experiment consisted of releasing particles of various sizes in an enclosed box of fan- generated, homogenous, isotropic, and stationary turbulent airflow and examining the particle behavior in a microgravity environment. The turbulence box was characterized in ground-based experiments using laser Doppler velocimetry techniques. Microgravity was established by free-floating the experiment apparatus during the parabolic trajectory of NASA's KC-135 reduced gravity aircraft. The microgravity generally lasted about 20 seconds, with about fifty parabolas per flight and one flight per day over a testing period of four days. To cover a broad range of flow regimes of interest, particles with Stokes numbers (St) of 1 to 300 were released in the turbulence box. The three- dimensional measurements of particle motion were made using a three-camera stereo imaging system with a particle-tracking algorithm. Digital photogrammetric techniques were used to determine the particle locations in three-dimensional space from the calibrated camera images. The epipolar geometry constraint was used to identify matching particles from the three different views and a direct spatial intersection scheme determined the coordinates of particles in three-dimensional space. Using velocity and acceleration constraints, particles in a sequence of frames were matched resulting in particle tracks and dispersion measurements. The goal was to compare the dispersion of different Stokes number particles in zero gravity and decouple the effects of inertia and gravity on the dispersion. Results show that higher inertia particles disperse less in zero gravity, in agreement with current models. Particles with St ~ 200

Analysis of User Requirements in Interactive 3D Video Systems

Directory of Open Access Journals (Sweden)

Haiyue Yuan

2012-01-01

Full Text Available The recent development of three dimensional (3D display technologies has resulted in a proliferation of 3D video production and broadcasting, attracting a lot of research into capture, compression and delivery of stereoscopic content. However, the predominant design practice of interactions with 3D video content has failed to address its differences and possibilities in comparison to the existing 2D video interactions. This paper presents a study of user requirements related to interaction with the stereoscopic 3D video. The study suggests that the change of view, zoom in/out, dynamic video browsing, and textual information are the most relevant interactions with stereoscopic 3D video. In addition, we identified a strong demand for object selection that resulted in a follow-up study of user preferences in 3D selection using virtual-hand and ray-casting metaphors. These results indicate that interaction modality affects users’ decision of object selection in terms of chosen location in 3D, while user attitudes do not have significant impact. Furthermore, the ray-casting-based interaction modality using Wiimote can outperform the volume-based interaction modality using mouse and keyboard for object positioning accuracy.

A tool for the estimation of the distribution of landslide area in R

Science.gov (United States)

Rossi, M.; Cardinali, M.; Fiorucci, F.; Marchesini, I.; Mondini, A. C.; Santangelo, M.; Ghosh, S.; Riguer, D. E. L.; Lahousse, T.; Chang, K. T.; Guzzetti, F.

2012-04-01

We have developed a tool in R (the free software environment for statistical computing, http://www.r-project.org/) to estimate the probability density and the frequency density of landslide area. The tool implements parametric and non-parametric approaches to the estimation of the probability density and the frequency density of landslide area, including: (i) Histogram Density Estimation (HDE), (ii) Kernel Density Estimation (KDE), and (iii) Maximum Likelihood Estimation (MLE). The tool is available as a standard Open Geospatial Consortium (OGC) Web Processing Service (WPS), and is accessible through the web using different GIS software clients. We tested the tool to compare Double Pareto and Inverse Gamma models for the probability density of landslide area in different geological, morphological and climatological settings, and to compare landslides shown in inventory maps prepared using different mapping techniques, including (i) field mapping, (ii) visual interpretation of monoscopic and stereoscopic aerial photographs, (iii) visual interpretation of monoscopic and stereoscopic VHR satellite images and (iv) semi-automatic detection and mapping from VHR satellite images. Results show that both models are applicable in different geomorphological settings. In most cases the two models provided very similar results. Non-parametric estimation methods (i.e., HDE and KDE) provided reasonable results for all the tested landslide datasets. For some of the datasets, MLE failed to provide a result, for convergence problems. The two tested models (Double Pareto and Inverse Gamma) resulted in very similar results for large and very large datasets (> 150 samples). Differences in the modeling results were observed for small datasets affected by systematic biases. A distinct rollover was observed in all analyzed landslide datasets, except for a few datasets obtained from landslide inventories prepared through field mapping or by semi-automatic mapping from VHR satellite imagery

Novel Threadlike Structures May Be Present on the Large Animal Organ Surface: Evidence in Swine Model

Directory of Open Access Journals (Sweden)

Kyoung-Hee Bae

2013-01-01

Full Text Available Background. The types of embryonic development probably provoke different paths of novel threadlike structure (NTS development. The authors hypothesized that NTS may be easily observed on the surface of swine intestines by using trypan blue staining method and visualization under an optical microscope. Methods. General anesthesia was administered to 2 Yorkshire pigs. The abdominal walls of the pigs were carefully dissected along the medial alba. NTSs were identified on organ surfaces under a stereoscopic microscope after trypan blue staining. Isolated NTS specimens obtained from the large intestine were subjected to 4′,6-diamidino-2-phenylindole (DAPI staining and observed using the polarized light microscopy to confirm whether the obtained structure fits the definition of NTS. Results. We found elastic, semitransparent threadlike structures (forming a network structure that had a milky-white color in situ and in vivo in swine large intestines. The samples showed distinct extinction of polarized light at every 90 degrees, and nucleus was shown to be rod shaped by DAPI staining, indicating that they meet the criteria of NTS. Conclusion. We used a swine model to demonstrate that NTS may be present on large animal organ surfaces. Our results may permit similar studies by using human specimens.

Solar Stereoscopy and Tomography

Directory of Open Access Journals (Sweden)

Markus J. Aschwanden

2011-10-01

Full Text Available We review stereoscopic and tomographic methods used in the solar corona, including ground-based and space-based measurements, using solar rotation or multiple spacecraft vantage points, in particular from the STEREO mission during 2007--2010. Stereoscopic and tomographic observations in the solar corona include large-scale structures, streamers, active regions, coronal loops, loop oscillations, acoustic waves in loops, erupting filaments and prominences, bright points, jets, plumes, flares, CME source regions, and CME-triggered global coronal waves. Applications in the solar interior (helioseismic tomography and reconstruction and tracking of CMEs from the outer corona and into the heliosphere (interplanetary CMEs are not included.

Video stereopsis of cardiac MR images

International Nuclear Information System (INIS)

Johnson, R.F. Jr.; Norman, C.

1988-01-01

This paper describes MR images of the heart acquired using a spin-echo technique synchronized to the electrocardiogram. Sixteen 0.5-cm-thick sections with a 0.1-cm gap between each section were acquired in the coronal view to cover all the cardiac anatomy including vasculature. Two sets of images were obtained with a subject rotation corresponding to the stereoscopic viewing angle of the eyes. The images were digitized, spatially registered, and processed by a three-dimensional graphics work station for stereoscopic viewing. Video recordings were made of each set of images and then temporally synchronized to produce a single video image corresponding to the appropriate eye view

Virtual Prototyping at CERN

Science.gov (United States)

Gennaro, Silvano De

The VENUS (Virtual Environment Navigation in the Underground Sites) project is probably the largest Virtual Reality application to Engineering design in the world. VENUS is just over one year old and offers a fully immersive and stereoscopic "flythru" of the LHC pits for the proposed experiments, including the experimental area equipment and the surface models that are being prepared for a territorial impact study. VENUS' Virtual Prototypes are an ideal replacement for the wooden models traditionally build for the past CERN machines, as they are generated directly from the EUCLID CAD files, therefore they are totally reliable, they can be updated in a matter of minutes, and they allow designers to explore them from inside, in a one-to-one scale. Navigation can be performed on the computer screen, on a stereoscopic large projection screen, or in immersive conditions, with an helmet and 3D mouse. By using specialised collision detection software, the computer can find optimal paths to lower each detector part into the pits and position it to destination, letting us visualize the whole assembly probess. During construction, these paths can be fed to a robot controller, which can operate the bridge cranes and build LHC almost without human intervention. VENUS is currently developing a multiplatform VR browser that will let the whole HEP community access LHC's Virtual Protoypes over the web. Many interesting things took place during the conference on Virtual Reality. For more information please refer to the Virtual Reality section.

A stereoscopic look into the bulk

Energy Technology Data Exchange (ETDEWEB)

Czech, Bartłomiej; Lamprou, Lampros; McCandlish, Samuel; Mosk, Benjamin [Stanford Institute for Theoretical Physics, Department of Physics, Stanford University,Stanford, CA 94305 (United States); Sully, James [Theory Group, SLAC National Accelerator LaboratoryMenlo Park, CA 94025 (United States)

2016-07-26

We present the foundation for a holographic dictionary with depth perception. The dictionary consists of natural CFT operators whose duals are simple, diffeomorphism-invariant bulk operators. The CFT operators of interest are the “OPE blocks,” contributions to the OPE from a single conformal family. In holographic theories, we show that the OPE blocks are dual at leading order in 1/N to integrals of effective bulk fields along geodesics or homogeneous minimal surfaces in anti-de Sitter space. One widely studied example of an OPE block is the modular Hamiltonian, which is dual to the fluctuation in the area of a minimal surface. Thus, our operators pave the way for generalizing the Ryu-Takayanagi relation to other bulk fields. Although the OPE blocks are non-local operators in the CFT, they admit a simple geometric description as fields in kinematic space — the space of pairs of CFT points. We develop the tools for constructing local bulk operators in terms of these non-local objects. The OPE blocks also allow for conceptually clean and technically simple derivations of many results known in the literature, including linearized Einstein’s equations and the relation between conformal blocks and geodesic Witten diagrams.

OPtimal backlight scanning for 3D crosstalk reduction in LCD TV

DEFF Research Database (Denmark)

Burini, Nino; Shu, Xiao; Jiao, Liangbao

2013-01-01

This work presents a method to determine the optimal backlight scanning signals to minimize crosstalk for time-sequential stereoscopic 3D on LCD TV with active shutter glasses. The solution is obtained through optimization of the variables defined by a model of backlight scanning that considers...... important aspects like liquid crystal transitions and light diffusion, subject to constraints that ensure the rendition of a uniform backlight. Compared with basic backlight scanning, the proposed method can increase luminance at a given crosstalk level or reduce crosstalk at a given luminance level....

“Pushing the Envelope” a modeling-based approach to the development of organic, responsive architectural form

Directory of Open Access Journals (Sweden)

David Yearley

2012-11-01

Full Text Available This paper tests design procedures for the development of complex, organic architectural forms. It illustrates a postgraduate student design process, implementing a development sequence based on the intelligent manipulation of architectural envelopes using a variety of existing modeling tools and emerging digital techniques. These stages of development respond to imposed spatial and environmental constraints. The tests began with full-scale modeling of small segments. The major constraints at this stage were spatial requirements and the physical characteristics of materials. The forms derived from the bending properties of prestressed green timber and the dimensions of shingle cladding. This was followed by digital 3D modeling using common commercial applications. At this stage initial models were derived from a traditional space requirement brief. The envelopes for these activities were then manipulated to respond to the spatial limitations imposed by surrounding buildings. This digital modeling process metaphorically “pushed the limits” as vertices of the envelope model were stretched and shifted to achieve a perceived “fit” between the two sets of spatial dimensions. The spatially manipulated geometry was then imported into Ecotect, an environmental analysis package. As an example, the envelope’s morphology and cladding material options on the acoustic qualities of the surrounding space were tested. The improved geometry was then imported into a Virtual Reality room, in which the spatial experience was simulated in presentations to the design team and potential occupants. This room utilized six projectors to create an immersive experience to users wearing stereoscopic goggles, and moving in a space surrounded by three large screens, creating a CAVE-like presentation space. Finally there was an attempt to complete the circle by returning from the simulated world to the physical worlds, by creating full-scale models from the digital

Photogrammetry using Apollo 16 orbital photography, part B

Science.gov (United States)

Wu, S. S. C.; Schafer, F. J.; Jordan, R.; Nakata, G. M.

1972-01-01

Discussion is made of the Apollo 15 and 16 metric and panoramic cameras which provided photographs for accurate topographic portrayal of the lunar surface using photogrammetric methods. Nine stereoscopic models of Apollo 16 metric photographs and three models of panoramic photographs were evaluated photogrammetrically in support of the Apollo 16 geologic investigations. Four of the models were used to collect profile data for crater morphology studies; three models were used to collect evaluation data for the frequency distributions of lunar slopes; one model was used to prepare a map of the Apollo 16 traverse area; and one model was used to determine elevations of the Cayley Formation. The remaining three models were used to test photogrammetric techniques using oblique metric and panoramic camera photographs. Two preliminary contour maps were compiled and a high-oblique metric photograph was rectified.

Preoperative evaluation of neurovascular relationships for microvascular decompression in the cerebellopontine angle in a virtual reality environment.

Science.gov (United States)

Du, Zhuo-Ying; Gao, Xiang; Zhang, Xiao-Luo; Wang, Zhi-Qiu; Tang, Wei-Jun

2010-09-01

In this paper the authors' goal was to evaluate the feasibility and efficacy of a virtual reality (VR) system in preoperative planning for microvascular decompression (MVD) procedures treating idiopathic trigeminal neuralgia and hemifacial spasm. The system's role in surgical simulation and training was also assessed. Between May 2008 and April 2009, the authors used the Dextroscope system to visualize the neurovascular complex and simulate MVD in the cerebellopontine angle in a VR environment in 16 patients (6 patients had trigeminal neuralgia and 10 had hemifacial spasm). Reconstructions were carried out 2-3 days before MVD. Images were printed in a red-blue stereoscopic format for teaching and discussion and were brought into the operating room to be compared with real-time intraoperative findings. The VR environment was a powerful aid for spatial understanding of the neurovascular relationship in MVD for operating surgeons and trainees. Through an initial series of comparison/confirmation experiences, the senior neurosurgeon became accustomed to the system. He could predict intraoperative problems and simulate surgical maneuvering, which increased his confidence in performing the procedure. The Dextroscope system is an easy and rapid method to create a stereoscopic neurovascular model for MVD that is highly concordant with intraoperative findings. It effectively shortens the learning curve and adds to the surgeon's confidence.

Object-Oriented Hierarchy Radiation Consistency for Different Temporal and Different Sensor Images

Directory of Open Access Journals (Sweden)

Nan Su

2018-02-01

Full Text Available In the paper, we propose a novel object-oriented hierarchy radiation consistency method for dense matching of different temporal and different sensor data in the 3D reconstruction. For different temporal images, our illumination consistency method is proposed to solve both the illumination uniformity for a single image and the relative illumination normalization for image pairs. Especially in the relative illumination normalization step, singular value equalization and linear relationship of the invariant pixels is combined used for the initial global illumination normalization and the object-oriented refined illumination normalization in detail, respectively. For different sensor images, we propose the union group sparse method, which is based on improving the original group sparse model. The different sensor images are set to a similar smoothness level by the same threshold of singular value from the union group matrix. Our method comprehensively considered the influence factors on the dense matching of the different temporal and different sensor stereoscopic image pairs to simultaneously improve the illumination consistency and the smoothness consistency. The radiation consistency experimental results verify the effectiveness and superiority of the proposed method by comparing two other methods. Moreover, in the dense matching experiment of the mixed stereoscopic image pairs, our method has more advantages for objects in the urban area.

Large Eddy Simulation Modeling of Flashback and Flame Stabilization in Hydrogen-Rich Gas Turbines Using a Hierarchical Validation Approach

Energy Technology Data Exchange (ETDEWEB)

Clemens, Noel [Univ. of Texas, Austin, TX (United States)

2015-09-30

This project was a combined computational and experimental effort to improve predictive capability for boundary layer flashback of premixed swirl flames relevant to gas-turbine power plants operating with high-hydrogen-content fuels. During the course of this project, significant progress in modeling was made on four major fronts: 1) use of direct numerical simulation of turbulent flames to understand the coupling between the flame and the turbulent boundary layer; 2) improved modeling capability for flame propagation in stratified pre-mixtures; 3) improved portability of computer codes using the OpenFOAM platform to facilitate transfer to industry and other researchers; and 4) application of LES to flashback in swirl combustors, and a detailed assessment of its capabilities and limitations for predictive purposes. A major component of the project was an experimental program that focused on developing a rich experimental database of boundary layer flashback in swirl flames. Both methane and high-hydrogen fuels, including effects of elevated pressure (1 to 5 atm), were explored. For this project, a new model swirl combustor was developed. Kilohertz-rate stereoscopic PIV and chemiluminescence imaging were used to investigate the flame propagation dynamics. In addition to the planar measurements, a technique capable of detecting the instantaneous, time-resolved 3D flame front topography was developed and applied successfully to investigate the flow-flame interaction. The UT measurements and legacy data were used in a hierarchical validation approach where flows with increasingly complex physics were used for validation. First component models were validated with DNS and literature data in simplified configurations, and this was followed by validation with the UT 1-atm flashback cases, and then the UT high-pressure flashback cases. The new models and portable code represent a major improvement over what was available before this project was initiated.

Turbulent swirling flow in a dynamic model of a uniflow-scavenged two-stroke engine

Science.gov (United States)

Ingvorsen, K. M.; Meyer, K. E.; Walther, J. H.; Mayer, S.

2014-06-01

It is desirable to use computational fluid dynamics for optimization of the in-cylinder processes in low-speed two-stroke uniflow-scavenged marine diesel engines. However, the complex nature of the turbulent swirling in-cylinder flow necessitates experimental data for validation of the used turbulence models. In the present work, the flow in a dynamic scale model of a uniflow-scavenged cylinder is investigated experimentally. The model has a transparent cylinder and a moving piston driven by a linear motor. The flow is investigated using phase-locked stereoscopic particle image velocimetry (PIV) and time-resolved laser Doppler anemometry (LDA). Radial profiles of the phase-locked mean and rms velocities are computed from the velocity fields recorded with PIV, and the accuracy of the obtained profiles is demonstrated by comparison with reference LDA measurements. Measurements are carried out at five axial positions for 15 different times during the engine cycle and show the temporal and spatial development of the swirling in-cylinder flow. The tangential velocity profiles in the bottom of the cylinder near the end of the scavenge process are characterized by a concentrated swirl resulting in wake-like axial velocity profiles and the occurrence of a vortex breakdown. After scavenge port closing, the axial velocity profiles indicate that large transient swirl-induced structures exist in the cylinder. Comparison with profiles obtained under steady-flow conditions shows that the scavenge flow cannot be assumed to be quasi-steady. The temporal development of the swirl strength is investigated by computing the angular momentum. The swirl strength shows an exponential decay from scavenge port closing to scavenge port opening corresponding to a reduction of 34 %, which is in good agreement with theoretical predictions.

High-speed laser diagnostics for the study of flame dynamics in a lean premixed gas turbine model combustor

Science.gov (United States)

Boxx, Isaac; Arndt, Christoph M.; Carter, Campbell D.; Meier, Wolfgang

2012-03-01

A series of measurements was taken on two technically premixed, swirl-stabilized methane-air flames (at overall equivalence ratios of ϕ = 0.73 and 0.83) in an optically accessible gas turbine model combustor. The primary diagnostics used were combined planar laser-induced fluorescence of the OH radical and stereoscopic particle image velocimetry (PIV) with simultaneous repetition rates of 10 kHz and a measurement duration of 0.8 s. Also measured were acoustic pulsations and OH chemiluminescence. Analysis revealed strong local periodicity in the thermoacoustically self-excited (or ` noisy') flame (ϕ = 0.73) in the regions of the flow corresponding to the inner shear layer and the jet-inflow. This periodicity appears to be the result of a helical precessing vortex core (PVC) present in that region of the combustor. The PVC has a precession frequency double (at 570 Hz) that of the thermo-acoustic pulsation (at 288 Hz). A comparison of the various data sets and analysis techniques applied to each flame suggests a strong coupling between the PVC and the thermo-acoustic pulsation in the noisy flame. Measurements of the stable (` quiet') flame (ϕ = 0.83) revealed a global fluctuation in both velocity and heat-release around 364 Hz, but no clear evidence of a PVC.

A Topological Array Trigger for AGIS, the Advanced Gamma ray Imaging System

Science.gov (United States)

Krennrich, F.; Anderson, J.; Buckley, J.; Byrum, K.; Dawson, J.; Drake, G.; Haberichter, W.; Imran, A.; Krawczynski, H.; Kreps, A.; Schroedter, M.; Smith, A.

2008-12-01

Next generation ground based γ-ray observatories such as AGIS1 and CTA2 are expected to cover a 1 km2 area with 50-100 imaging atmospheric Cherenkov telescopes. The stereoscopic view ol air showers using multiple view points raises the possibility to use a topological array trigger that adds substantial flexibility, new background suppression capabilities and a reduced energy threshold. In this paper we report on the concept and technical implementation of a fast topological trigger system, that makes use of real time image processing of individual camera patterns and their combination in a stereoscopic array analysis. A prototype system is currently under construction and we discuss the design and hardware of this topological array trigger system.

Golden Gate National Recreation Area Vegetation Inventory Project

Data.gov (United States)

California Natural Resource Agency — High resolution vegetation polygons mapped by the National Park Service. The vegetation units of this map were determined through stereoscopic interpretation of...

Visual Discomfort and Depth-of-Field

Directory of Open Access Journals (Sweden)

Louise O'Hare

2013-05-01

Full Text Available Visual discomfort has been reported for certain visual stimuli and under particular viewing conditions, such as stereoscopic viewing. In stereoscopic viewing, visual discomfort can be caused by a conflict between accommodation and convergence cues that may specify different distances in depth. Earlier research has shown that depth-of-field, which is the distance range in depth in the scene that is perceived to be sharp, influences both the perception of egocentric distance to the focal plane, and the distance range in depth between objects in the scene. Because depth-of-field may also be in conflict with convergence and the accommodative state of the eyes, we raised the question of whether depth-of-field affects discomfort when viewing stereoscopic photographs. The first experiment assessed whether discomfort increases when depth-of-field is in conflict with coherent accommodation–convergence cues to distance in depth. The second experiment assessed whether depth-of-field influences discomfort from a pre-existing accommodation–convergence conflict. Results showed no effect of depth-of-field on visual discomfort. These results suggest therefore that depth-of-field can be used as a cue to depth without inducing discomfort in the viewer, even when cue conflicts are large.

MISR L2 TOA/Cloud Stereo Product subset for the ICARTT region V002

Data.gov (United States)

National Aeronautics and Space Administration — MISR Level 2 TOA/Cloud Stereo Product containing the Stereoscopically Derived Cloud Mask (SDCM), cloud winds, Reflecting Level Reference Altitude (RLRA), with...

The world's northernmost harbour seal population-how many are there?

Directory of Open Access Journals (Sweden)

Benjamin Merkel

Full Text Available This study presents the first abundance estimate for the world's northernmost harbour seal (Phoca vitulina population, which resides in Svalbard, Norway, based on three digital stereoscopic photographic surveys conducted in 2009 and 2010. The counts from these high resolution 3D images were combined with a novel method for estimating correction factors for animals that were in the water at the time of the surveys, in which extensive behavioural data from radio-tagged harbour seals were used together with age distribution data to estimate the proportion of seals of various age and sex classes hauled out at the times of the surveys. To detect possible seasonal shifts in age distribution between surveys, lengths of hauled out seals were measured from the stereoscopic images. No body-length differences were detected between the surveys; but, this may be due to a high degree of sexual dimorphism exhibited in this population. Applying the modelled correction factors, a total of 1888 (95% CI: 1660-3023, 1742 (1381-3549 and 1812 (1656-4418 harbour seals were estimated for the surveys flown on 01 August 2009, 01 August 2010 and 19 August 2010, respectively. The similarity between the three survey estimates (despite significant differences in the number of animals actually counted on the photos from each survey effort suggests that the variation in numbers of hauled out seals is reasonably accurately adjusted for by the haul-out probability model. The low population size, the limited spatial distribution of the population and its reduced genetic diversity make this population vulnerable to chance events, such as disease epidemics.

An Eulerian-Eulerian CFD Simulation of Air-Water Flow in a Pipe Separator

Directory of Open Access Journals (Sweden)

E.A. Afolabi

2014-06-01

Full Text Available This paper presents a three dimensional Computational Fluid Dynamics (CFD of air-water flow using Eulerian –Eulerian multiphase model and RSM mixture turbulence model to investigate its hydrodynamic flow behaviour in a 30 mm pipe separator. The simulated results are then compared with the stereoscopic PIV measurements at different axial positions. The comparison shows that the velocity distribution can be predicted with high accuracy using CFD. The numerical velocity profiles are also found to be in good qualitative agreement with the experimental measurements. However, there were some discrepancies between the CFD results and the SPIV measurements at some axial positions away from the inlet section. Therefore, the CFD model could provide good physical understanding on the hydrodynamics flow behaviour for air-water in a pipe separator.

The interplay between rheology and pre-existing structures in the lithosphere and its influence on intraplate tectonics: Insights from scaled physical analogue models.

Science.gov (United States)

Santimano, T. N.; Adiban, P.; Pysklywec, R.

2017-12-01

The primary controls of deformation in the lithosphere are related to its rheological properties. In addition, recent work reveals that inherited zones of weakness in the deep lithosphere are prevalent and can also define tectonic activity. To understand how deformation is genetically related to rheology and/or pre-existing structures, we compare a set of physical analogue models with the presence and absence of a fault in the deep lithosphere. The layered lithosphere scaled models of a brittle upper crust, viscous lower crust and viscous mantle lithosphere are deformed in a convergent setting. Deformation of the model is recorded using high spatial and temporal stereoscopic cameras. We use Particle Image Velocimetry (PIV) to acquire a time-series dataset and study the velocity field and subsequently strain in the model. The finished model is also cut into cross-section revealing the finite internal structures that are then compared to the topography of the model. Preliminary results show that deformation in models with an inherited fault in the mantle lithosphere is accommodated by displacement along the fault plane that propagates into the overlying viscous lower crust and brittle upper crust. Here, the majority of the deformation is localized along the fault in a brittle manner. This is in contrast to the model absent of a fault that also displays significant amounts of deformation. In this setting, ductile deformation is accommodated by folding and thickening of the viscous layers and flexural shearing of the brittle upper crust. In these preliminary experiments, the difference in the strength profile between the mantle lithosphere and the lower crust is within the same order of magnitude. Future experiments will include models where the strength difference is an order of magnitude. This systematic study aids in understanding the role of rheology and deep structures particularly in transferring stress over time to the surface and is therefore fundamental in

Flight Deck I-Glasses, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Flight Deck i-Glasses is a color, stereoscopic 3-D display mounted on consumer style eye glass frames that will enhance operator performance and multi-modal...

Deployment and Intelligent Nanosatellite Operations Colorado Final Technical Report

National Research Council Canada - National Science Library

Hansen, Elaine; Beckwith, Dave; Koehler, Christ; Levin-Stankevich, Steve; Michels, Jennifer; Wichman, Steve

2006-01-01

The main purpose of the DINO satellite was to generate topographic maps of the tops of clouds through stereoscopic imaging based on photographs from the on-board digital cameras, with most processing...

A GeoWall with Physics and Astronomy Applications

Science.gov (United States)

Dukes, Phillip; Bruton, Dan

2008-03-01

A GeoWall is a passive stereoscopic projection system that can be used by students, teachers, and researchers for visualization of the structure and dynamics of three-dimensional systems and data. The type of system described here adequately provides 3-D visualization in natural color for large or small groups of viewers. The name ``GeoWall'' derives from its initial development to visualize data in the geosciences.1 An early GeoWall system was developed by Paul Morin at the electronic visualization laboratory at the University of Minnesota and was applied in an introductory geology course in spring of 2001. Since that time, several stereoscopic media, which are applicable to introductory-level physics and astronomy classes, have been developed and released into the public domain. In addition to the GeoWall's application in the classroom, there is considerable value in its use as part of a general science outreach program. In this paper we briefly describe the theory of operation of stereoscopic projection and the basic necessary components of a GeoWall system. Then we briefly describe how we are using a GeoWall as an instructional tool for the classroom and informal astronomy education and in research. Finally, we list sources for several of the free software media in physics and astronomy available for use with a GeoWall system.

Evaluation of the Data-Ray DR96L 4 x 3 Aspect Ratio, 22-Inch Diagonal Flat Screen Monochrome CRT Monitor

National Research Council Canada - National Science Library

2001-01-01

.... Based on results of our evaluation of the third sample NIDL cannot certify the Data-Ray DR96L monochrome monitor as being suitable for suitable monoscopic or stereoscopic operation in IEC workstations...

Understanding and caring for an operating microscope

Directory of Open Access Journals (Sweden)

Ismael Cordero

2014-04-01

Full Text Available An operating or surgical microscope is an optical instrument that provides the surgeon with a stereoscopic, high quality magnified and illuminated image of the small structures in the surgical area.

Training in virtual reality: a comparison of technology types

International Nuclear Information System (INIS)

Sebok, Angelia; Nystad, Espen

2004-11-01

For maintenance work in the nuclear industry, a primary goal is reducing radiation exposure. Workers need to be trained to perform their tasks quickly and efficiently to minimize their time in the radioactive area, thus limiting their exposure. This requires that workers become familiar with the area in which they will work, the radiation distribution, and the tasks they will perform. Virtual Reality technology can provide this training in a safe environment. VR systems are available in a variety of formats, ranging from desktop VR to fully immersive head-mounted displays. One question regarding the use of VR for training is 'Which technology type best supports training?' This report describes an experiment evaluating different VR display technology types in terms of their ability to support different types of learning. The VR systems include two desktop types (monoscopic and stereoscopic view), a large screen display, and a head-mounted display. Procedural, configuration, and assembly training types were evaluated. Learning was assessed in terms of objective task performance and radiation awareness. Retention and transfer of training were evaluated for procedural learning. In addition, subjective questionnaire data were also gathered. Findings were that technology type did not matter for procedural, configuration, or assembly knowledge. Objective performance, by the end of the training session, was equivalent across display technology types in all of these learning conditions. On the other hand, retention and transfer of training appeared to be better supported by stereoscopic displays, particularly the large screen stereoscopic display. Subjects rated perceived performance and simulator sickness highest in the head-mounted display condition. Sense of presence (SOP) was best in the large screen stereoscopic condition for procedural learning, but there were no differences for SOP in assembly learning. This study suggests that sense of presence and performance are

History of falling and visual ability among independently living elderly in Sweden.

Science.gov (United States)

Källstrand-Eriksson, Jeanette; Hildingh, Cathrine; Bengtsson, Boel

2016-01-01

The aim of this study was to assess the performance-based visual ability among independently living elderly subjects and to investigate whether there was any association between visual ability and falls. A total of 298 randomly selected subjects aged 70-85 years were invited for an examination including monocular and binocular visual acuity (VA), contrast sensitivity (CS), stereoscopic vision, and monocular visual fields (VFs), which were integrated to estimate the binocular VFs. Type of lenses used in their habitual correction was noted. Out of the 212 subjects who were examined, 38% reported at least one fall and 48% of these reported at least two falls during the last 2 years. Most subjects had normal results; 90% had normal binocular VA, 85% had normal binocular CS, and ~80% had positive stereopsis. Twenty-nine subjects had VF defects in the lower quadrants of the binocular VF, and 14 of these reported at least one fall. A significant association was seen between one fall or more and VA better eye, the odds ratio (OR) was 2.26, P=0.013, and between recurrent falls and lack of stereoscopic vision, the OR was 3.23, P=0.002; no other functional test showed any significant association with recurrent falls. The ORs were 1.58 for worse binocular VA, 0.60 for worse binocular CS, and 0.71 for non-normal stereoscopic vision for at least one fall, but wide confidence intervals made it difficult to draw firm conclusions about any association. Bifocal or progressive spectacles were worn by 71% with no significant difference between fallers and nonfallers (P=0.078). Even though ~40% of the total sample had experienced one or more falls, the only visual function test significantly associated with falls were VA better eye, lack of stereoscopic vision, and recurrent falls. Our results suggest that there may be more powerful predictors of falling than decreased visual ability.

Six dimensional analysis with daily stereoscopic x-ray imaging of intrafraction patient motion in head and neck treatments using five points fixation masks

International Nuclear Information System (INIS)

Linthout, Nadine; Verellen, Dirk; Tournel, Koen; Storme, Guy

2006-01-01

The safety margins used to define the Planning Target Volume (PTV) should reflect the accuracy of the target localization during treatment that comprises both the reproducibility of the patient positioning and the positional uncertainty of the target, so both the inter- and intrafraction motion of the target. Our first aim in this study was to determine the intrafraction motion of patients immobilized with a five-point thermoplastic mask for head and neck treatments. The five-point masks have the advantage that the patient's shoulders as well as the cranial part of the patient's head is covered with the thermoplastic material that improves the overall immobilization of the head and neck region of the patient. Thirteen patients were consecutively assigned to use a five-point thermoplastic mask. The patients were positioned by tracking of infrared markers (IR) fixed to the immobilization device and stereoscopic x-ray images were used for daily on-line setup verification. Repositioning was carried out prior to treatment as needed; rotations were not corrected. Movements during treatment were monitored by real-time IR tracking. Intrafraction motion and rotation was supplementary assessed by a six-degree-of-freedom (6-D) fusion of x-ray images, taken before and after all 385 treatments, with DRR images generated from the planning CT data. The latter evaluates the movement of the patient within the thermoplastic mask independent from the mask movement, where IR tracking evaluates the movement of the mask caused by patient movement in the mask. These two movements are not necessarily equal to each other. The maximum intrafraction movement detected by IR tracking showed a shift [mean (SD; range)] of -0.1(0.7; 6.0), 0.1(0.6; 3.6), -0.2(0.8;5.5) mm in the vertical, longitudinal, and lateral direction, respectively, and rotations of 0.0(0.2; 1.6), 0.0(0.2; 1.7) and 0.2(0.2; 2.4) degrees about the vertical, longitudinal, and lateral axis, respectively. The standard deviations

La serie de vistas estereoscópicas de España de J. Andrieu y un paseo por el Madrid de 1867

Directory of Open Access Journals (Sweden)

Hervás León, Miguel

2005-12-01

Full Text Available In this study an important and little-known series of 300 stereoscopic views by the French photographer Jean Andrieu is presented. These photos constitute a monumental and urban portrait of Isabelline Spain, and permit us to take a mini tour of Madrid in 1867. The author includes historical and technical explanations of stereoscopic photography.

Presentamos un estudio de esta importante y poco conocida serie de 300 vistas estereoscópicas del fotógrafo francés Jean Andrieu, que constituye un retrato monumental y urbano de la España isabelina y que nos permite realizar un pequeño recorrido por el Madrid de 1867. Se acompañan explicaciones históricas y técnicas básicas sobre fotografía estereoscópica.

The future of three-dimensional medical imaging

International Nuclear Information System (INIS)

Peter, T.M.

1996-01-01

The past 15 years have witnessed an explosion in medical imaging technology, and none more so than in the tomographic imaging modalities of CT and MRI. Prior to 1975, 3-D imaging was largely performed in the minds of radiologists and surgeons, assisted by the modalities of conventional x-ray tomography and stereoscopic radiography. However today, with the advent of imaging techniques which ower their existence to computer technology, three-dimensional image acquisition is fast becoming the norm and the clinician finally has access to sets of data that represent the entire imaged volume. Stereoscopic image visualization has already begun to reappear as a viable means of visualizing 3 D medical images. The future of 3-D imaging is exciting and will undoubtedly move further in the direction of virtual reality. (author)

Quantum vision in three dimensions

Science.gov (United States)

Roth, Yehuda

We present four models for describing a 3-D vision. Similar to the mirror scenario, our models allow 3-D vision with no need for additional accessories such as stereoscopic glasses or a hologram film. These four models are based on brain interpretation rather than pure objective encryption. We consider the observer "subjective" selection of a measuring device and the corresponding quantum collapse into one of his selected states, as a tool for interpreting reality in according to the observer concepts. This is the basic concept of our study and it is introduced in the first model. Other models suggests "soften" versions that might be much easier to implement. Our quantum interpretation approach contribute to the following fields. In technology the proposed models can be implemented into real devices, allowing 3-D vision without additional accessories. Artificial intelligence: In the desire to create a machine that exchange information by using human terminologies, our interpretation approach seems to be appropriate.

Neural Integration of Information Specifying Human Structure from Form, Motion, and Depth

Science.gov (United States)

Jackson, Stuart; Blake, Randolph

2010-01-01

Recent computational models of biological motion perception operate on ambiguous two-dimensional representations of the body (e.g., snapshots, posture templates) and contain no explicit means for disambiguating the three-dimensional orientation of a perceived human figure. Are there neural mechanisms in the visual system that represent a moving human figure’s orientation in three dimensions? To isolate and characterize the neural mechanisms mediating perception of biological motion, we used an adaptation paradigm together with bistable point-light (PL) animations whose perceived direction of heading fluctuates over time. After exposure to a PL walker with a particular stereoscopically defined heading direction, observers experienced a consistent aftereffect: a bistable PL walker, which could be perceived in the adapted orientation or reversed in depth, was perceived predominantly reversed in depth. A phase-scrambled adaptor produced no aftereffect, yet when adapting and test walkers differed in size or appeared on opposite sides of fixation aftereffects did occur. Thus, this heading direction aftereffect cannot be explained by local, disparity-specific motion adaptation, and the properties of scale and position invariance imply higher-level origins of neural adaptation. Nor is disparity essential for producing adaptation: when suspended on top of a stereoscopically defined, rotating globe, a context-disambiguated “globetrotter” was sufficient to bias the bistable walker’s direction, as were full-body adaptors. In sum, these results imply that the neural signals supporting biomotion perception integrate information on the form, motion, and three-dimensional depth orientation of the moving human figure. Models of biomotion perception should incorporate mechanisms to disambiguate depth ambiguities in two-dimensional body representations. PMID:20089892

Virtual X-ray imaging techniques in an immersive casting simulation environment

International Nuclear Information System (INIS)

Li, Ning; Kim, Sung-Hee; Suh, Ji-Hyun; Cho, Sang-Hyun; Choi, Jung-Gil; Kim, Myoung-Hee

2007-01-01

A computer code was developed to simulate radiograph of complex casting products in a CAVE TM -like environment. The simulation is based on the deterministic algorithms and ray tracing techniques. The aim of this study is to examine CAD/CAE/CAM models at the design stage, to optimize the design and inspect predicted defective regions with fast speed, good accuracy and small numerical expense. The present work discusses the algorithms for the radiography simulation of CAD/CAM model and proposes algorithmic solutions adapted from ray-box intersection algorithm and octree data structure specifically for radiographic simulation of CAE model. The stereoscopic visualization of full-size of product in the immersive casting simulation environment as well as the virtual X-ray images of castings provides an effective tool for design and evaluation of foundry processes by engineers and metallurgists

Automatic online and real-time tumour motion monitoring during stereotactic liver treatments on a conventional linac by combined optical and sparse monoscopic imaging with kilovoltage x-rays (COSMIK)

DEFF Research Database (Denmark)

Bertholet, Jenny; Toftegaard, Jakob; Hansen, Rune

2018-01-01

during the CBCT is estimated from the auto-segmented positions in the projections and used to optimize an external correlation model (ECM) of internal motion as a function of external motion. During treatment, the ECM estimates the internal motion from the external motion at 20 Hz. KV images are acquired...... every 3 s, auto-segmented, and used to update the ECM for baseline shifts between internal and external motion. The COSMIK method was validated using Calypso-recorded internal tumour motion with simultaneous camera-recorded external motion for 15 liver stereotactic body radiotherapy (SBRT) patients....... The validation included phantom experiments and simulations hereof for 12 fractions and further simulations for 42 fractions. The simulations compared the accuracy of COSMIK with ECM-based monitoring without model updates and with model updates based on stereoscopic imaging as well as continuous kilovoltage...

ArtifactVis2: Managing real-time archaeological data in immersive 3D environments

KAUST Repository

Smith, Neil; Knabb, Kyle; Defanti, Connor; Weber, Philip P.; Schulze, Jü rgen P.; Prudhomme, Andrew; Kuester, Falko; Levy, Thomas E.; Defanti, Thomas A.

2013-01-01

In this paper, we present a stereoscopic research and training environment for archaeologists called ArtifactVis2. This application enables the management and visualization of diverse types of cultural datasets within a collaborative virtual 3D

High Resolution Autostereoscopic Cockpit Display, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The utility of stereoscopic 3D image representation in many applications is now well established. It is not just a matter of stereo being better than 2D, but of...

Flow analysis of vortex generators on wing sections by stereoscopic particle image velocimetry measurements

DEFF Research Database (Denmark)

Velte, Clara Marika; Hansen, Martin Otto Laver; Cavar, Dalibor

2008-01-01

a wind turbine blade. The low Reynolds number is chosen on the basis that this is a fundamental investigation of the structures of the flow induced by vortex generators and the fact that one obtains a thicker boundary layer and larger structures evoked by the actuating devices, which are easier...... generators are applied. The idea behind the experiments is that the results will be offered for validation of modeling of the effect of vortex generators using various numerical codes. Initial large eddy simulation (LES) computations have been performed that show the same qualitative behaviour...

Extraction and textural characterization of above-ground areas from aerial stereo pairs: a quality assessment

Science.gov (United States)

Baillard, C.; Dissard, O.; Jamet, O.; Maître, H.

Above-ground analysis is a key point to the reconstruction of urban scenes, but it is a difficult task because of the diversity of the involved objects. We propose a new method to above-ground extraction from an aerial stereo pair, which does not require any assumption about object shape or nature. A Digital Surface Model is first produced by a stereoscopic matching stage preserving discontinuities, and then processed by a region-based Markovian classification algorithm. The produced above-ground areas are finally characterized as man-made or natural according to the grey level information. The quality of the results is assessed and discussed.

Blow-off characteristics of turbulent premixed flames in curved-wall Jet Burner

KAUST Repository

Mansour, Morkous S.; Mannaa, O.; Chung, Suk-Ho

2015-01-01

and simultaneously stereoscopic particle image velocimetry (SPIV) quantified the turbulent flow field features. Ethylene/air flames were stabilized in CWJ burner to determine the sequence of events leading to blowoff. For stably burning flames far from blowoff

Numerically- analysed Multiwavelet Transform computations ...

African Journals Online (AJOL)

pc

2018-03-05

Mar 5, 2018 ... The multiwavelet has two-scale : Research ... two wavelets functions beginning from two box functions shown in .... compression for multi-view auto-stereoscopic displays,” in ... [10] T. Kesavamurthy and S. Rani, “Dicom Color.

A quantitative measurement of binocular color fusion limit for different disparities

Science.gov (United States)

Chen, Zaiqing; Shi, Junsheng; Tai, Yonghan; Huang, Xiaoqiao; Yun, Lijun; Zhang, Chao

2018-01-01

Color asymmetry is a common phenomenon in stereoscopic display system, which can cause visual fatigue or visual discomfort. When the color difference between the left and right eyes exceeds a threshold value, named binocular color fusion limit, color rivalry is said to occur. The most important information brought by stereoscopic displays is the depth perception produced by the disparity. As the stereo pair stimuli are presented separately to both eyes with disparities and those two monocular stimuli differ in color but share an iso-luminance polarity, it is possible for stereopsis and color rivalry to coexist. In this paper, we conducted an experiment to measure the color fusion limit for different disparity levels. In particular, it examines how the magnitude and sign of disparity affect the binocular color fusion limit that yields a fused, stable stereoscopic percept. The binocular color fusion limit was measured at five levels of disparities: 0, +/-60, +/-120 arc minutes for a sample color point which was selected from the 1976 CIE u'v' chromaticity diagram. The experimental results showed that fusion limit for the sample point varied with the level and sign of disparity. It was an interesting result that the fusion limit increased as the disparity decreases at crossed disparity direction (sign -), but there is almost no big change at uncrossed disparity direction (sign +). We found that color fusion was more difficult to achieve at the crossed disparity direction than at the uncrossed disparity direction.

The sensitivity of schlieren systems for viewing ultrasound

International Nuclear Information System (INIS)

Hanstead, P.D.

1976-01-01

A novel set of simplifying assumptions makes computer prediction of schlieren sensitivity possible economically. Predictions correlate with experimental and published figures. Other means of improving sensitivity are given. A compact schlieren system giving binocular stereoscopic viewing is described

Large field SPIV with separated sheets in a spanwise plane of a turbulent boundary layer with vortex generators

DEFF Research Database (Denmark)

Foucaut, J.M.; Coudert, S.; Braud, C.

2012-01-01

The Stereoscopic PIV is nowadays a well established measurement technique for turbulent flows. However, the accuracy and the spatial resolution are still highly questionable in presence of complex flow with both strong gradients and out of plane motions. To give guidelines for both setup and meas......The Stereoscopic PIV is nowadays a well established measurement technique for turbulent flows. However, the accuracy and the spatial resolution are still highly questionable in presence of complex flow with both strong gradients and out of plane motions. To give guidelines for both setup...... of measurements by increasing the velocity dynamic range especially. It also presents the enhancement of accuracy due to the light sheets separation for characterizing streamwise vortices (i.e. perpendicular to the sheet). The present experiment was performed in the Laboratoire de Mécanique de Lille wind tunnel...

Virtual 3-dimensional preoperative planning with the dextroscope for excision of a 4th ventricular ependymoma.

Science.gov (United States)

Anil, S M; Kato, Y; Hayakawa, M; Yoshida, K; Nagahisha, S; Kanno, T

2007-04-01

Advances in computer imaging and technology have facilitated enhancement in surgical planning with a 3-dimensional model of the surgical plan of action utilizing advanced visualization tools in order to plan individual interactive operations with the aid of the dextroscope. This provides a proper 3-dimensional imaging insight to the pathological anatomy and sets a new dimension in collaboration for training and education. The case of a seventeen-year-old female, being operated with the aid of a preoperative 3-dimensional virtual reality planning and the practical application of the neurosurgical operation, is presented. This young lady presented with a two-year history of recurrent episodes of severe, global, throbbing headache with episodes of projectile vomiting associated with shoulder pain which progressively worsened. She had no obvious neurological deficits on clinical examination. CT and MRI showed a contrast-enhancing midline posterior fossa space-occupying lesion. Utilizing virtual imaging technology with the aid of a dextroscope which generates stereoscopic images, a 3-dimensional image was produced with the CT and MRI images. A preoperative planning for excision of the lesion was made and a real-time 3-dimensional volume was produced and surgical planning with the dextroscope was made and the lesion excised. Virtual reality has brought new proportions in 3-dimensional planning and management of various complex neuroanatomical problems that are faced during various operations. Integration of 3-dimensional imaging with stereoscopic vision makes understanding the complex anatomy easier and helps improve decision making in patient management.

Virtual tape measure for the operating microscope: system specifications and performance evaluation.

Science.gov (United States)

Kim, M Y; Drake, J M; Milgram, P

2000-01-01

The Virtual Tape Measure for the Operating Microscope (VTMOM) was created to assist surgeons in making accurate 3D measurements of anatomical structures seen in the surgical field under the operating microscope. The VTMOM employs augmented reality techniques by combining stereoscopic video images with stereoscopic computer graphics, and functions by relying on an operator's ability to align a 3D graphic pointer, which serves as the end-point of the virtual tape measure, with designated locations on the anatomical structure being measured. The VTMOM was evaluated for its baseline and application performances as well as its application efficacy. Baseline performance was determined by measuring the mean error (bias) and standard deviation of error (imprecision) in measurements of non-anatomical objects. Application performance was determined by comparing the error in measuring the dimensions of aneurysm models with and without the VTMOM. Application efficacy was determined by comparing the error in selecting the appropriate aneurysm clip size with and without the VTMOM. Baseline performance indicated a bias of 0.3 mm and an imprecision of 0.6 mm. Application bias was 3.8 mm and imprecision was 2.8 mm for aneurysm diameter. The VTMOM did not improve aneurysm clip size selection accuracy. The VTMOM is a potentially accurate tool for use under the operating microscope. However, its performance when measuring anatomical objects is highly dependent on complex visual features of the object surfaces. Copyright 2000 Wiley-Liss, Inc.

Using Stereo Vision to Support the Automated Analysis of Surveillance Videos

Science.gov (United States)

Menze, M.; Muhle, D.

2012-07-01

Video surveillance systems are no longer a collection of independent cameras, manually controlled by human operators. Instead, smart sensor networks are developed, able to fulfil certain tasks on their own and thus supporting security personnel by automated analyses. One well-known task is the derivation of people's positions on a given ground plane from monocular video footage. An improved accuracy for the ground position as well as a more detailed representation of single salient people can be expected from a stereoscopic processing of overlapping views. Related work mostly relies on dedicated stereo devices or camera pairs with a small baseline. While this set-up is helpful for the essential step of image matching, the high accuracy potential of a wide baseline and the according good intersection geometry is not utilised. In this paper we present a stereoscopic approach, working on overlapping views of standard pan-tilt-zoom cameras which can easily be generated for arbitrary points of interest by an appropriate reconfiguration of parts of a sensor network. Experiments are conducted on realistic surveillance footage to show the potential of the suggested approach and to investigate the influence of different baselines on the quality of the derived surface model. Promising estimations of people's position and height are retrieved. Although standard matching approaches show helpful results, future work will incorporate temporal dependencies available from image sequences in order to reduce computational effort and improve the derived level of detail.

USING STEREO VISION TO SUPPORT THE AUTOMATED ANALYSIS OF SURVEILLANCE VIDEOS

Directory of Open Access Journals (Sweden)

M. Menze

2012-07-01

Full Text Available Video surveillance systems are no longer a collection of independent cameras, manually controlled by human operators. Instead, smart sensor networks are developed, able to fulfil certain tasks on their own and thus supporting security personnel by automated analyses. One well-known task is the derivation of people’s positions on a given ground plane from monocular video footage. An improved accuracy for the ground position as well as a more detailed representation of single salient people can be expected from a stereoscopic processing of overlapping views. Related work mostly relies on dedicated stereo devices or camera pairs with a small baseline. While this set-up is helpful for the essential step of image matching, the high accuracy potential of a wide baseline and the according good intersection geometry is not utilised. In this paper we present a stereoscopic approach, working on overlapping views of standard pan-tilt-zoom cameras which can easily be generated for arbitrary points of interest by an appropriate reconfiguration of parts of a sensor network. Experiments are conducted on realistic surveillance footage to show the potential of the suggested approach and to investigate the influence of different baselines on the quality of the derived surface model. Promising estimations of people’s position and height are retrieved. Although standard matching approaches show helpful results, future work will incorporate temporal dependencies available from image sequences in order to reduce computational effort and improve the derived level of detail.

Pollutant dispersion in boundary layers exposed to rural-to-urban transitions : Varying the spanwise length scale of the roughness

NARCIS (Netherlands)

Tomas, J.M.; Eisma, H.E.; Pourquie, M.J.B.M.; Elsinga, G.E.; Jonker, H.J.J.; Westerweel, J.

2017-01-01

Both large-eddy simulations (LES) and water-tunnel experiments, using simultaneous stereoscopic particle image velocimetry and laser-induced fluorescence, have been used to investigate pollutant dispersion mechanisms in regions where the surface changes from rural to urban roughness. The urban

Three-dimensional particle image velocimetry in a generic can-type gas turbine combustor

CSIR Research Space (South Africa)

Meyers, BC

2009-09-01

Full Text Available The three-dimensional flow field inside a generic can-type, forward flow, experimental combustor was measured. A stereoscopic Particle Image Velocimetry (PIV) system was used to obtain the flow field of the combustor in the non-reacting condition...

Advanced Audiovisual Rendering, Gesture-Based Interaction and Distributed Delivery for Immersive and Interactive Media Services

NARCIS (Netherlands)

Niamut, O.A.; Kochale, A.; Ruiz Hidalgo, J.; Macq, J-F.; Kienast, G.

2011-01-01

The media industry is currently being pulled in the often-opposing directions of increased realism (high resolution, stereoscopic, large screen) and personalisation (selection and control of content, availability on many devices). A capture, production, delivery and rendering system capable of

Bluff-body drag reduction using a deflector

Science.gov (United States)

Fourrié, Grégoire; Keirsbulck, Laurent; Labraga, Larbi; Gilliéron, Patrick

2011-02-01

A passive flow control on a generic car model was experimentally studied. This control consists of a deflector placed on the upper edge of the model rear window. The study was carried out in a wind tunnel at Reynolds numbers based on the model height of 3.1 × 105 and 7.7 × 105. The flow was investigated via standard and stereoscopic particle image velocimetry, Kiel pressure probes and surface flow visualization. The aerodynamic drag was measured using an external balance and calculated using a wake survey method. Drag reductions up to 9% were obtained depending on the deflector angle. The deflector increases the separated region on the rear window. The results show that when this separated region is wide enough, it disrupts the development of the counter-rotating longitudinal vortices appearing on the lateral edges of the rear window. The current study suggests that flow control on such geometries should consider all the flow structures that contribute to the model wake flow.

The ASTER Global Digital Elevation Model (GDEM) -for societal benefit -

Science.gov (United States)

Hato, M.; Tsu, H.; Tachikawa, T.; Abrams, M.; Bailey, B.

2009-12-01

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) was developed jointly by the Ministry of Economy, Trade and Industry (METI) of Japan and the United States National Aeronautics and Space Administration (NASA) under the agreement of contribution to GEOSS and a public release was started on June 29th. ASTER GDEM can be downloaded to users from the Earth Remote Sensing Data Analysis Center (ERSDAC) of Japan and NASA’s Land Processes Distributed Active Archive Center (LP DAAC) free of charge. The ASTER instrument was built by METI and launched onboard NASA’s Terra spacecraft in December 1999. It has an along-track stereoscopic capability using its near infrared spectral band (NIR) and its nadir-viewing and backward-viewing telescopes to acquire stereo image data with a base-to-height ratio of 0.6. The ASTER GDEM was produced by applying newly-developed automated algorithm to more than 1.2 million NIR data Produced DEMs of all scene data was stacked after cloud masking and finally partitioned into 1° x 1°unit (called ‘tile’) data for convenience of distribution and handling by users. Before start of public distribution, ERSDAC and USGS/NASA together with many volunteers did validation and characterization by using a preliminary product of the ASTER GDEM. As a result of validation, METI and NASA evaluated that Version 1 of the ASTER GDEM has enough quality to be used as “experimental” or “research grade” data and consequently decided to release it. The ASTER GDEM covering almost all land area of from 83N to 83S on the earth represents as an important contribution to the global earth observation community. We will show our effort of development of ASTER GDEM and its accuracy and character.

History of falling and visual ability among independently living elderly in Sweden

Directory of Open Access Journals (Sweden)

Källstrand-Eriksson J

2016-07-01

Full Text Available Jeanette Källstrand-Eriksson,1 Cathrine Hildingh,1 Boel Bengtsson2 1School of Health and Welfare, Halmstad University, Halmstad, 2Department of Clinical Sciences in Malmö, Ophthalmology, Lund University, Malmö, Sweden Purpose: The aim of this study was to assess the performance-based visual ability among independently living elderly subjects and to investigate whether there was any association between visual ability and falls.Subjects and methods: A total of 298 randomly selected subjects aged 70–85 years were invited for an examination including monocular and binocular visual acuity (VA, contrast sensitivity (CS, stereoscopic vision, and monocular visual fields (VFs, which were integrated to estimate the binocular VFs. Type of lenses used in their habitual correction was noted.Results: Out of the 212 subjects who were examined, 38% reported at least one fall and 48% of these reported at least two falls during the last 2 years. Most subjects had normal results; 90% had normal binocular VA, 85% had normal binocular CS, and ~80% had positive stereopsis. Twenty-nine subjects had VF defects in the lower quadrants of the binocular VF, and 14 of these reported at least one fall. A significant association was seen between one fall or more and VA better eye, the odds ratio (OR was 2.26, P=0.013, and between recurrent falls and lack of stereoscopic vision, the OR was 3.23, P=0.002; no other functional test showed any significant association with recurrent falls. The ORs were 1.58 for worse binocular VA, 0.60 for worse binocular CS, and 0.71 for non-normal stereoscopic vision for at least one fall, but wide confidence intervals made it difficult to draw firm conclusions about any association. Bifocal or progressive spectacles were worn by 71% with no significant difference between fallers and nonfallers (P=0.078.Conclusion: Even though ~40% of the total sample had experienced one or more falls, the only visual function test significantly associated

Study of the sensitivity of the H.E.S.S.2 experiment below 300 GeV and indirect search of dark matter with the H.E.S.S. Data

International Nuclear Information System (INIS)

Masbou, J.

2010-09-01

The H.E.S.S. telescope (High Energy Stereoscopic System) is an experiment of four imaging Cherenkov Telescope looking on gamma rays from 100 GeV to 100 TeV. In 2012, the experiment will be upgraded in a second phase with a fifth telescope of 28 m of diameter in the center of the existing system. At the threshold of 15 GeV, electromagnetic shower will be detected only by this big telescope so a new data analysis is needed. A new method based on a multidimensional analysis has been developed. Therefore, the energy of electromagnetic shower is well reconstructed with a good discrimination down to 30 GeV. At low energy, the sensitivity will be at a few percent of the Crab in 50 hours. This new method has been tested on H.E.S.S. data and is very competitive with respect to the other energy reconstruction methods; an extension for stereoscopic events is also shown. The calibration processes and the results of tests of photomultipliers are described. A propagation model of cosmic rays has been developed to study diffuse gamma ray emission. Protons and helium nuclei have been propagated in the galaxy to estimate the emission of neutral pion decays after an interaction with the interstellar medium. The map production is described from the beginning to the end. I have estimated the sensitivity of H.E.S.S. to the prediction of the model. The Sagittarius dwarf galaxy is studied as a dark matter dominated object. I used the most efficient analysis of the H.E.S.S collaboration and decomposed the data as a function of the zenith angle to decrease the energy threshold. (author)

SUN-TO-EARTH CHARACTERISTICS OF THE 2012 JULY 12 CORONAL MASS EJECTION AND ASSOCIATED GEO-EFFECTIVENESS

Energy Technology Data Exchange (ETDEWEB)

Hu, Huidong; Liu, Ying D.; Wang, Rui; Yang, Zhongwei [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China); Möstl, Christian, E-mail: liuxying@spaceweather.ac.cn [Space Research Institute, Austrian Academy of Sciences, A-8042 Graz (Austria)

2016-10-01

We analyze multi-spacecraft observations associated with the 2012 July 12 coronal mass ejection (CME), covering the source region on the Sun from the Solar Dynamics Observatory , stereoscopic imaging observations from the Solar Terrestrial Relations Observatory ( STEREO ), magnetic field characteristics from Mercury Surface, Space Environment, Geochemistry, and Ranging ( MESSENGER ), and type II radio burst and in situ measurements from Wind . A triangulation method based on STEREO stereoscopic observations is employed to determine the kinematics of the CME, and the outcome is compared with the results derived from the type II radio burst using a solar wind electron density model. A Grad–Shafranov technique is applied to Wind in situ data to reconstruct the flux-rope structure and compare it with the observations of the solar source region, which helps in understanding the geo-effectiveness associated with the CME structure. Our conclusions are as follows: (1) the CME undergoes an impulsive acceleration, a rapid deceleration before reaching MESSENGER , and then a gradual deceleration out to 1 au, which should be considered in CME kinematics models; (2) the type II radio burst was probably produced from a high-density interaction region between the CME-driven shock and a nearby streamer or from the shock flank with lower heights, which implies uncertainties in the determination of CME kinematics using solely type II radio bursts; (3) the flux-rope orientation and chirality deduced from in situ reconstructions at Wind agree with those obtained from solar source observations; (4) the prolonged southward magnetic field near the Earth is mainly from the axial component of the largely southward inclined flux rope, which indicates the importance of predicting both the flux-rope orientation and magnetic field components in geomagnetic activity forecasting.

Real-time skin feature identification in a time-sequential video stream

Science.gov (United States)

Kramberger, Iztok

2005-04-01

Skin color can be an important feature when tracking skin-colored objects. Particularly this is the case for computer-vision-based human-computer interfaces (HCI). Humans have a highly developed feeling of space and, therefore, it is reasonable to support this within intelligent HCI, where the importance of augmented reality can be foreseen. Joining human-like interaction techniques within multimodal HCI could, or will, gain a feature for modern mobile telecommunication devices. On the other hand, real-time processing plays an important role in achieving more natural and physically intuitive ways of human-machine interaction. The main scope of this work is the development of a stereoscopic computer-vision hardware-accelerated framework for real-time skin feature identification in the sense of a single-pass image segmentation process. The hardware-accelerated preprocessing stage is presented with the purpose of color and spatial filtering, where the skin color model within the hue-saturation-value (HSV) color space is given with a polyhedron of threshold values representing the basis of the filter model. An adaptive filter management unit is suggested to achieve better segmentation results. This enables the adoption of filter parameters to the current scene conditions in an adaptive way. Implementation of the suggested hardware structure is given at the level of filed programmable system level integrated circuit (FPSLIC) devices using an embedded microcontroller as their main feature. A stereoscopic clue is achieved using a time-sequential video stream, but this shows no difference for real-time processing requirements in terms of hardware complexity. The experimental results for the hardware-accelerated preprocessing stage are given by efficiency estimation of the presented hardware structure using a simple motion-detection algorithm based on a binary function.

A FULL STUDY ON THE SUN–EARTH CONNECTION OF AN EARTH-DIRECTED CME MAGNETIC FLUX ROPE

Energy Technology Data Exchange (ETDEWEB)

Vemareddy, Panditi [Indian Institute of Astrophysics, II Block, Koramangala, Bangalore-560 034 (India); Mishra, Wageesh, E-mail: vemareddy@iiap.res.in, E-mail: wageesh@ustc.edu.cn [Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei-230026 (China)

2015-11-20

We present an investigation of an eruption event of a coronal mass ejection (CME) magnetic flux rope (MFR) from the source active region (AR) NOAA 11719 on 2013 April 11 utilizing observations from the Solar Dynamic Observatory, the Solar Terrestrial Relations Observatory, the Solar and Heliospheric Observatory, and the WIND spacecraft. The source AR consists of a pre-existing sigmoidal structure stacked over a filament channel which is regarded as an MFR system. EUV observations of low corona suggest further development of this MFR system by added axial flux through tether-cutting reconnection of loops at the middle of the sigmoid under the influence of continuous slow flux motions for two days. Our study implies that the MFR system in the AR is initiated to upward motion by kink instability and further driven by torus instability. The CME morphology, captured in simultaneous three-point coronagraph observations, is fitted with a Graduated Cylindrical Shell (GCS) model and discerns an MFR topology with its orientation aligning with a magnetic neutral line in the source AR. This MFR expands self-similarly and is found to have source AR twist signatures in the associated near-Earth magnetic cloud (MC). We further derived the kinematics of this CME propagation by employing a plethora of stereoscopic as well as single-spacecraft reconstruction techniques. While stereoscopic methods perform relatively poorly compared to other methods, fitting methods worked best in estimating the arrival time of the CME compared to in situ measurements. Supplied with the values of constrained solar wind velocity, drag parameter, and three-dimensional kinematics from the GCS fit, we construct CME kinematics from the drag-based model consistent with in situ MC arrival.

SUN-TO-EARTH CHARACTERISTICS OF THE 2012 JULY 12 CORONAL MASS EJECTION AND ASSOCIATED GEO-EFFECTIVENESS

International Nuclear Information System (INIS)

Hu, Huidong; Liu, Ying D.; Wang, Rui; Yang, Zhongwei; Möstl, Christian

2016-01-01

We analyze multi-spacecraft observations associated with the 2012 July 12 coronal mass ejection (CME), covering the source region on the Sun from the Solar Dynamics Observatory , stereoscopic imaging observations from the Solar Terrestrial Relations Observatory ( STEREO ), magnetic field characteristics from Mercury Surface, Space Environment, Geochemistry, and Ranging ( MESSENGER ), and type II radio burst and in situ measurements from Wind . A triangulation method based on STEREO stereoscopic observations is employed to determine the kinematics of the CME, and the outcome is compared with the results derived from the type II radio burst using a solar wind electron density model. A Grad–Shafranov technique is applied to Wind in situ data to reconstruct the flux-rope structure and compare it with the observations of the solar source region, which helps in understanding the geo-effectiveness associated with the CME structure. Our conclusions are as follows: (1) the CME undergoes an impulsive acceleration, a rapid deceleration before reaching MESSENGER , and then a gradual deceleration out to 1 au, which should be considered in CME kinematics models; (2) the type II radio burst was probably produced from a high-density interaction region between the CME-driven shock and a nearby streamer or from the shock flank with lower heights, which implies uncertainties in the determination of CME kinematics using solely type II radio bursts; (3) the flux-rope orientation and chirality deduced from in situ reconstructions at Wind agree with those obtained from solar source observations; (4) the prolonged southward magnetic field near the Earth is mainly from the axial component of the largely southward inclined flux rope, which indicates the importance of predicting both the flux-rope orientation and magnetic field components in geomagnetic activity forecasting.

A FULL STUDY ON THE SUN–EARTH CONNECTION OF AN EARTH-DIRECTED CME MAGNETIC FLUX ROPE

International Nuclear Information System (INIS)

Vemareddy, Panditi; Mishra, Wageesh

2015-01-01

We present an investigation of an eruption event of a coronal mass ejection (CME) magnetic flux rope (MFR) from the source active region (AR) NOAA 11719 on 2013 April 11 utilizing observations from the Solar Dynamic Observatory, the Solar Terrestrial Relations Observatory, the Solar and Heliospheric Observatory, and the WIND spacecraft. The source AR consists of a pre-existing sigmoidal structure stacked over a filament channel which is regarded as an MFR system. EUV observations of low corona suggest further development of this MFR system by added axial flux through tether-cutting reconnection of loops at the middle of the sigmoid under the influence of continuous slow flux motions for two days. Our study implies that the MFR system in the AR is initiated to upward motion by kink instability and further driven by torus instability. The CME morphology, captured in simultaneous three-point coronagraph observations, is fitted with a Graduated Cylindrical Shell (GCS) model and discerns an MFR topology with its orientation aligning with a magnetic neutral line in the source AR. This MFR expands self-similarly and is found to have source AR twist signatures in the associated near-Earth magnetic cloud (MC). We further derived the kinematics of this CME propagation by employing a plethora of stereoscopic as well as single-spacecraft reconstruction techniques. While stereoscopic methods perform relatively poorly compared to other methods, fitting methods worked best in estimating the arrival time of the CME compared to in situ measurements. Supplied with the values of constrained solar wind velocity, drag parameter, and three-dimensional kinematics from the GCS fit, we construct CME kinematics from the drag-based model consistent with in situ MC arrival

Why can't my child see 3D television?

Science.gov (United States)

Creavin, Alexandra L; Creavin, Samuel T; Brown, Raymond D; Harrad, Richard A

2014-08-01

A child encountering difficulty in watching three-dimensional (3D) stereoscopic displays could have an underlying ocular disorder. It is therefore valuable to understand the differential diagnoses and so conduct an appropriate clinical assessment to address concerns about poor 3D vision.

Measurement and Image Processing Techniques for Particle Image Velocimetry Using Solid-Phase Carbon Dioxide

Science.gov (United States)

2014-03-27

stereoscopic PIV: the angular displacement configuration and the translation configuration. The angular displacement configuration is most commonly used today...images were processed using ImageJ, an open-source, Java -based image processing software available from the National Institute of Health (NIH). The

Range and variability in gesture-based interactions with medical images : do non-stereo versus stereo visualizations elicit different types of gestures?

NARCIS (Netherlands)

Beurden, van M.H.P.H.; IJsselsteijn, W.A.

2010-01-01

The current paper presents a study into the range and variability of natural gestures when interacting with medical images, using traditional non stereo and stereoscopic modes of presentation. The results have implications for the design of computer-vision algorithms developed to support natural

Attentional control within 3-D space

NARCIS (Netherlands)

Theeuwes, J.; Atchley, P.; Kramer, A.F.

1998-01-01

Four experiments investigated whether directing attention to a particular plane in depth enables observers to filter out information from another depth plane. Observers viewed stereoscopic displays and searched for a red line segment among green line segments. The results showed that directing

Planar measurements of velocity and concentration of turbulent mixing in a T-junction

DEFF Research Database (Denmark)

Ingvorsen, Kristian Mark; Meyer, Knud Erik; Nielsen, N. F.

Turbulent mixing of two isothermal air streams in a T-junction of square ducts are investigated. Three dimensional velocity fields and turbulent kinetic energy are measured with stereoscopic Particle Image Velocimetry (PIV). The concentration field is obtained with a planar Mie scattering technique...

Towards a format-agnostic approach for production, delivery and rendering of immersive media

NARCIS (Netherlands)

Niamut, O.A.; Kochale, A.; Hidalgo, J.R.; Kaiser, R.; Spille, J.; Macq, J.F.; Kienast, G.; Schreer, O.; Shirley, B.

2013-01-01

The media industry is currently being pulled in the often-opposing directions of increased realism (high resolution, stereoscopic, large screen) and personalization (selection and control of content, availability on many devices). We investigate the feasibility of an end-to-end format-agnostic

SPIV investigations of correlation between streamwise vorticity and velocity in the wake of a vortex generator in a boundary layer

DEFF Research Database (Denmark)

Velte, Clara Marika; Okulov, Valery; Hansen, Martin Otto Laver

2013-01-01

The current work describes the experimental parametric study of streamwise vortices generated in a boundary layer by a rectangular vane (commonly named vortex generator) mounted perpendicularly to the wall and at an angle to the oncoming flow. Stereoscopic Particle Image Velocimetry measurements ...

3D display system using monocular multiview displays

Science.gov (United States)

Sakamoto, Kunio; Saruta, Kazuki; Takeda, Kazutoki

2002-05-01

A 3D head mounted display (HMD) system is useful for constructing a virtual space. The authors have researched the virtual-reality systems connected with computer networks for real-time remote control and developed a low-priced real-time 3D display for building these systems. We developed a 3D HMD system using monocular multi-view displays. The 3D displaying technique of this monocular multi-view display is based on the concept of the super multi-view proposed by Kajiki at TAO (Telecommunications Advancement Organization of Japan) in 1996. Our 3D HMD has two monocular multi-view displays (used as a visual display unit) in order to display a picture to the left eye and the right eye. The left and right images are a pair of stereoscopic images for the left and right eyes, then stereoscopic 3D images are observed.

A Virtual Holographic Display Case for Museum Installations

Directory of Open Access Journals (Sweden)

Manuela Chessa

2015-12-01

Full Text Available Today, it is important in society to make artworks accessible to mass audiences and to widen participation in culture. In such a context, virtual reality is one of the areas of greatest interest: new devices and new techniques are affordable for many users, and virtual and real worlds are often mixed together. In this paper, we propose a "virtual holographic" display, i.e. a stereoscopic virtual reality system that is able to replicate the behavior of a real showcase for exhibitions. It works in a completely virtual manner and it can yield to a new generation of entertainment "holographic" installations. We evaluate such a system through an experimental session with 20 users. In particular, we compare the proposed system, based on a stereoscopic technique (TD3D, with respect to a standard motion parallax technique in terms of the users' perceptual experience.

Real-time embedded system for stereo video processing for multiview displays

Science.gov (United States)

Berretty, R.-P. M.; Riemens, A. K.; Machado, P. F.

2007-02-01

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.

Stereo advantage for a peg-in-hole task using a force-feedback manipulator

Science.gov (United States)

Spain, Edward H.

1990-01-01

An improved assessment methodology has been implemented at NOSC and tested using an instrumented peg-in-hole (PiH) taskboard. Several aspects of the methodology are discussed in light of their implications for future studies of manipulator performance. Using a simple (but high-fidelity) force-feedback manipulator, a group of 9 trained operators showed a consistent advantage for stereoscopic TV viewing over monoscopic TV viewing when performing the PiH task. To introduce a controlled element of spatial uncertainty into the testing procedure, taskboard orientation relative to the manipulator and remote video camera head was changed in a randomized order on a trial-by-trial basis. The stereoscopic advantage demonstrated by this study can reasonably be expected to be even more pronounced as the quality of the stereo TV interface is improved and force-feedback provided through the manipulator system is diminished and/or distorted.

Stereo Pair, Salt Lake City, Utah

Science.gov (United States)

2002-01-01

The 2002 Winter Olympics are hosted by Salt Lake City at several venues within the city, in nearby cities, and within the adjacent Wasatch Mountains. This image pair provides a stereoscopic map view of north central Utah that includes all of these Olympic sites. In the south, next to Utah Lake, Provo hosts the ice hockey competition. In the north, northeast of the Great Salt Lake, Ogden hosts curling and the nearby Snowbasin ski area hosts the downhill events. In between, southeast of the Great Salt Lake, Salt Lake City hosts the Olympic Village and the various skating events. Further east, across the Wasatch Mountains, the Park City ski resort hosts the bobsled, ski jumping, and snowboarding events. The Winter Olympics are always hosted in mountainous terrain. This view shows the dramatic landscape that makes the Salt Lake City region a world-class center for winter sports.This stereoscopic image was generated by draping a Landsat satellite image over a Shuttle Radar Topography Mission digital elevation model. Two differing perspectives were then calculated, one for each eye. They can be seen in 3-D by viewing the left image with the right eye and the right image with the left eye (cross-eyed viewing or by downloading and printing the image pair and viewing them with a stereoscope. When stereoscopically merged, the result is a vertically exaggerated view of Earth's surface in its full three dimensions.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR

Three dimensional visualization of medical images

International Nuclear Information System (INIS)

Suto, Yasuzo

1992-01-01

Three dimensional visualization is a stereoscopic technique that allows the diagnosis and treatment of complicated anatomy site of the bone and organ. In this article, the current status and technical application of three dimensional visualization are introduced with special reference to X-ray CT and MRI. The surface display technique is the most common for three dimensional visualization, consisting of geometric model, voxel element, and stereographic composition techniques. Recent attention has been paid to display method of the content of the subject called as volume rendering, whereby information on the living body is provided accurately. The application of three dimensional visualization is described in terms of diagnostic imaging and surgical simulation. (N.K.)

In situ vocal fold properties and pitch prediction by dynamic actuation of the songbird syrinx

DEFF Research Database (Denmark)

Düring, Daniel N; Knörlein, Benjamin J; Elemans, Coen P H

2017-01-01

, forces and torques exerted on, and motion of the syringeal skeleton during song. Here, we present a novel marker-based 3D stereoscopic imaging technique to reconstruct 3D motion of servo-controlled actuation of syringeal muscle insertions sites in vitro and focus on two muscles controlling sound pitch......The biomechanics of sound production forms an integral part of the neuromechanical control loop of avian vocal motor control. However, we critically lack quantification of basic biomechanical parameters describing the vocal organ, the syrinx, such as material properties of syringeal elements...... motion and forces, acoustic effects of muscle recruitment, and calibration of computational birdsong models, enabling experimental access to the entire neuromechanical control loop of vocal motor control....

RECORDING AND MODELING OF FORTRESSES AND CASTLES WITH UAS. SOME STUDY CASES IN JAEN (SOUTHERN SPAIN

Directory of Open Access Journals (Sweden)

J. Cardenal

2016-06-01

Full Text Available The province of Jaen (Southern Spain has one of the largest concentrations of medieval fortresses of all Europe. Moreover ancient Iberian settlements located in oppida (fortified villages and dated at VI-IV BC also are outstanding examples of historical heritage landmarks in the region. Most of these places are being restored or under documentation analysis to prevent their progressive deterioration. These places have several geometric characteristics in common, such as isolated locations, elongated shapes, largemedium size objects (in the order of tens to few hundred of meters, architectural features with vertical development (such as masonry or rammed earth walls, towers, gates, battlements, etc or without it (walls, buildings or paths layouts at ground level. The object size, the required level of details and accuracy (of the order of some few cm and both vertical and horizontal features imply that present UAS techniques can be advantageously used with respect to conventional aerial and terrestrial photogrammetric techniques. Vertical stereoscopic and oblique convergent UAS photogrammetric networks combined with processing techniques based on Structure from Motion (SfM algorithms allow detailed low cost 2D/3D products. The proper selection of the UAS, camera, image acquisition mode (stop and/or cruising, the network and the processing software will determine the quality of final products and their usefulness in metric documentation, 3D modelization or museology. The efficiency of the use of UAS has been analyzed in several selected examples in Jaen (Burgalimar and Berrueco castles, Xth and XIIIth centuries, respectively, and the Iberian Puente Tablas oppidum, Vth-IVth centuries BC.

Lenticular system : full-color, limited-angle, autostereoscopic alternative to holography

NARCIS (Netherlands)

Zonneveld, F.W.; Huitema, A.G.M.; Joel, A.H.; Arancha Fernández, M.; Waes, Van P.F.G.M.; Haar Romenij, ter B.M.

1996-01-01

The microlenticular system is a method of hard copy imaging that provides stereoscopic cues without the use of special glasses or viewing devices. Therefore, it is called an autostereoscopic technique. The microlenticular system consists of a layer of cylindric lenses combined with a photographic

3D Stereo Visualization for Mobile Robot Tele-Guide

DEFF Research Database (Denmark)

Livatino, Salvatore

2006-01-01

The use of 3D stereoscopic visualization may provide a user with higher comprehension of remote environments in tele-operation when compared to 2D viewing. In particular, a higher perception of environment depth characteristics, spatial localization, remote ambient layout, as well as faster system...

From Purgatorius ceratops to Homo sapiens

Indian Academy of Sciences (India)

important stages in human evolution. Extan t primates ... with concomitant development of binocular, stereoscopic and .... phenomena as disparate as climatic changes, geological impacts and floral shifts. ... Global cooling and increased glacia- tion in the .... product of diffuse co-evolu tionary in teractions with angiosperms.

Light Field Rendering for Head Mounted Displays using Pixel Reprojection

DEFF Research Database (Denmark)

Hansen, Anne Juhler; Klein, Jákup; Kraus, Martin

2017-01-01

Light field displays have advantages over traditional stereoscopic head mounted displays, for example, because they can overcome the vergence-accommodation conflict. However, rendering light fields can be a heavy task for computers due to the number of images that have to be rendered. Since much ...

Influence of light sheet separation on SPIV measurement in a large field spanwise plane

DEFF Research Database (Denmark)

Foucaut, J M; Coudert, S.; Braud, C.

2014-01-01

Stereoscopic particle image velocimetry (SPIV) is nowadays a well-established measurement technique for turbulent flows. However, the accuracy and the spatial resolution are still highly questionable in the presence of complex flow with both strong gradients and out-of-plane motions. To give guid...

Multi-particle three-dimensional coordinate estimation in real-time optical manipulation

DEFF Research Database (Denmark)

Dam, Jeppe Seidelin; Perch-Nielsen, Ivan R.; Palima, Darwin

2009-01-01

We have previously shown how stereoscopic images can be obtained in our three-dimensional optical micromanipulation system [J. S. Dam et al, Opt. Express 16, 7244 (2008)]. Here, we present an extension and application of this principle to automatically gather the three-dimensional coordinates for...

Computer Graphics Instruction in VizClass

Science.gov (United States)

Grimes, Douglas; Warschauer, Mark; Hutchinson, Tara; Kuester, Falko

2005-01-01

"VizClass" is a university classroom environment designed to offer students in computer graphics and engineering courses up-to-date visualization technologies. Three digital whiteboards and a three-dimensional stereoscopic display provide complementary display surfaces. Input devices include touchscreens on the digital whiteboards, remote…

Stereoscopic Roadside Curb Height Measurement using V-Disparity

DEFF Research Database (Denmark)

Matu, Florin-Octavian; Vlaykov, Iskren; Thøgersen, Mikkel

2014-01-01

Managing road assets, such as roadside curbs, is one of the interests of municipalities. As an interesting application of computer vision, this paper proposes a system for automated measurement of the height of the roadside curbs. The developed system uses the spatial information available...... results show that the system can measure the height of the roadside curb with good accuracy and precision....

Stereoscopic construction and practice of optoelectronic technology textbook

Science.gov (United States)

Zhou, Zigang; Zhang, Jinlong; Wang, Huili; Yang, Yongjia; Han, Yanling

2017-08-01

It is a professional degree course textbook for the Nation-class Specialty—Optoelectronic Information Science and Engineering, and it is also an engineering practice textbook for the cultivation of photoelectric excellent engineers. The book seeks to comprehensively introduce the theoretical and applied basis of optoelectronic technology, and it's closely linked to the current development of optoelectronic industry frontier and made up of following core contents, including the laser source, the light's transmission, modulation, detection, imaging and display. At the same time, it also embodies the features of the source of laser, the transmission of the waveguide, the electronic means and the optical processing methods.

Novel 3D Stereoscopic Film Compression using Multiwavelet

African Journals Online (AJOL)

pc

2018-03-05

Mar 5, 2018 ... this works based on observing the parsing evaluation of the ... enhance the performance of the quality of the 3D film is .... enhance our understanding of compression the video fra .... rt stereoscopy, for example in future can.

Three extensions to subtractive crosstalk reduction

NARCIS (Netherlands)

Smit, F.A.; Liere, van R.; Fröhlich, B.; Fröhlich, B.; Blach, R.; Liere, van R.

2007-01-01

Stereo displays suffer from crosstalk, an effect that reduces or even inhibits the viewer¿s ability to correctly fuse stereoscopic images. In this paper, three extensions for improved software crosstalk reduction are introduced. First, we propose a reduction method operating in CIELAB color space to

Supersonic Combustion Ramjet Research

Science.gov (United States)

2012-08-01

was in collaboration with Prof. R. Bowersox (Texas A&M University) and Dr. K. Kobayashi ( Japanese Aerospace Exploration Agency, JAXA). 4.2 Ignition... cinema stereoscopic PIV system for the measurement of micro- and meso-scale turbulent premixed flame dynamics,” Paper B13, 5th US Combustion

Plexus muscularis profundus and associated interstitial cells. I. Light microscopical studies of mouse small intestine

DEFF Research Database (Denmark)

Rumessen, J J; Thuneberg, L

1982-01-01

The zinc iodide/osmic acid (ZIO) method was used in a modification that selectively stained nerves and associated interstitial cells of Cajal (ICC) of muscularis externa. Due to its selectivity the method allowed a detailed stereoscopical analysis of whole mounts with respect to the topography an...

Vortex statistics in turbulent rotating convection

NARCIS (Netherlands)

Kunnen, R.P.J.; Clercx, H.J.H.; Geurts, B.J.

2010-01-01

The vortices emerging in rotating turbulent Rayleigh-Bénard convection in water at Rayleigh number Ra=6.0×108 are investigated using stereoscopic particle image velocimetry and by direct numerical simulation. The so-called Q criterion is used to detect the vortices from velocity fields. This

Assessing diabetic retinopathy using two-field digital photography and the influence of JPEG-comoression

NARCIS (Netherlands)

Stellingwerf, C; Hardus, PLLJ; Hooymans, JMM

Objective: To study the effectiveness of two digital 50degrees photographic fields per eye, stored compressed or integrally, in the grading of diabetic retinopathy, in comparison to 35-mm colour slides. Subjects and methods: Two-field digital non-stereoscopic retinal photographs and two-field 35-mm

Operational Based Vision Assessment Research: Depth Perception

Science.gov (United States)

2014-11-01

Potential hazards of viewing 3-D stereoscopic television, cinema and computer games: a review. Ophthalmic Physiol Opt 2011; 31:111-22. 75. Watt SJ...the 2012 Interservice/Industry Training, Simulation, and Education Conference (I/ITSEC); 2012 Dec 3-6; Orlando, FL. 82. Blake R, Fox R. The

Regimes of Vorticity in the Wake of a Rectangular Vortex Generator

DEFF Research Database (Denmark)

Velte, Clara Marika; Okulov, Valery; Hansen, Martin Otto Laver

2011-01-01

This paper concerns the study of the secondary structures generated in the wake of a wall mounted rectangular vane, commonly referred to as a vortex generator. The study has been conducted by Stereoscopic PIV measurements in a wind tunnel and supplementary flow visualizations in a water channel...

An investigation of visual selection priority of objects with texture and crossed and uncrossed disparities

Science.gov (United States)

Khaustova, Dar'ya; Fournier, Jérôme; Wyckens, Emmanuel; Le Meur, Olivier

2014-02-01

The aim of this research is to understand the difference in visual attention to 2D and 3D content depending on texture and amount of depth. Two experiments were conducted using an eye-tracker and a 3DTV display. Collected fixation data were used to build saliency maps and to analyze the differences between 2D and 3D conditions. In the first experiment 51 observers participated in the test. Using scenes that contained objects with crossed disparity, it was discovered that such objects are the most salient, even if observers experience discomfort due to the high level of disparity. The goal of the second experiment is to decide whether depth is a determinative factor for visual attention. During the experiment, 28 observers watched the scenes that contained objects with crossed and uncrossed disparities. We evaluated features influencing the saliency of the objects in stereoscopic conditions by using contents with low-level visual features. With univariate tests of significance (MANOVA), it was detected that texture is more important than depth for selection of objects. Objects with crossed disparity are significantly more important for selection processes when compared to 2D. However, objects with uncrossed disparity have the same influence on visual attention as 2D objects. Analysis of eyemovements indicated that there is no difference in saccade length. Fixation durations were significantly higher in stereoscopic conditions for low-level stimuli than in 2D. We believe that these experiments can help to refine existing models of visual attention for 3D content.

Resultados preliminares de um sistema computadorizado e estereoscópico para pupilometria in vivo Preliminary results of a computerized and stereoscopic system for in vivo pupillometry

Directory of Open Access Journals (Sweden)

Luis Alberto Vieira de Carvalho

2008-12-01

ophthalmoscope helmet and a typical diving mask as support for a high-resolution and sensitivity CCD. Using an IBM compatible computer sequences of video in AVI format were digitized for several seconds at a mean rate of 30 Hz. Algorithms using principles of image processing were implemented for detection of the pupil edges. RESULTS: We present preliminary results of this system for a voluntary patient. Data for the horizontal (x and vertical (y central position and for the diameter of the pupil were then exported to files that could be read by typical spread sheet programs (Excel. CONCLUSIONS: In this manner, precise data can be obtained stereoscopically (for both pupils at the same time for any patient, given that the accommodation process is guaranteed by using a white LED virtual mire located 6 meters from the patient's eye. An electronic board precisely controls the level of illumination. We believe here developed instrument may be useful in certain ophthalmic practices where precise pupil geometric data are needed.

Contextual Cueing Effect in Spatial Layout Defined by Binocular Disparity

Science.gov (United States)

Zhao, Guang; Zhuang, Qian; Ma, Jie; Tu, Shen; Liu, Qiang; Sun, Hong-jin

2017-01-01

Repeated visual context induces higher search efficiency, revealing a contextual cueing effect, which depends on the association between the target and its visual context. In this study, participants performed a visual search task where search items were presented with depth information defined by binocular disparity. When the 3-dimensional (3D) configurations were repeated over blocks, the contextual cueing effect was obtained (Experiment 1). When depth information was in chaos over repeated configurations, visual search was not facilitated and the contextual cueing effect largely crippled (Experiment 2). However, when we made the search items within a tiny random displacement in the 2-dimentional (2D) plane but maintained the depth information constant, the contextual cueing was preserved (Experiment 3). We concluded that the contextual cueing effect was robust in the context provided by 3D space with stereoscopic information, and more importantly, the visual system prioritized stereoscopic information in learning of spatial information when depth information was available. PMID:28912739

Standardized access, display, and retrieval of medical video

Science.gov (United States)

Bellaire, Gunter; Steines, Daniel; Graschew, Georgi; Thiel, Andreas; Bernarding, Johannes; Tolxdorff, Thomas; Schlag, Peter M.

1999-05-01

The system presented here enhances documentation and data- secured, second-opinion facilities by integrating video sequences into DICOM 3.0. We present an implementation for a medical video server extended by a DICOM interface. Security mechanisms conforming with DICOM are integrated to enable secure internet access. Digital video documents of diagnostic and therapeutic procedures should be examined regarding the clip length and size necessary for second opinion and manageable with today's hardware. Image sources relevant for this paper include 3D laparoscope, 3D surgical microscope, 3D open surgery camera, synthetic video, and monoscopic endoscopes, etc. The global DICOM video concept and three special workplaces of distinct applications are described. Additionally, an approach is presented to analyze the motion of the endoscopic camera for future automatic video-cutting. Digital stereoscopic video sequences are especially in demand for surgery . Therefore DSVS are also integrated into the DICOM video concept. Results are presented describing the suitability of stereoscopic display techniques for the operating room.

Stereoscopic CAD and Environmental Sculpture: Enhancement of the Design Process in the Visual Arts

Science.gov (United States)

Fisher, Robert N.; Bandini, Pier L.

1989-09-01

In this paper, co-authors Robert Fisher and Pier Luigi Bandini describe their personal observations concerning stereo enhancements of computer graphics images employed in their research. in Part One, Robert Fisher, a professional sculptor, Professor and Artist-in-Residence in the College of Engineering at Penn State, cites three recent environmental sculpture projects: "See-scape," "A Page from the Book of Skies," and an as yet untitled work. Wireframe images, interior views of architectural spaces, and complex imagery are rendered comprehensible by stereo 3-D. In Part Two, Pier L. Bandini, Associate Professor of Architecture and Director of the Architecture CAD Lab at Penn State, describes the virtues of the stereo-enhanced wireframe model--the benefits of the "see-through coupled with a complete awareness of the whole space." The final example, of a never-realized XVIII-century project, suggests a new and profound application of stereo 3-D to historical inquiry, namely, the experience of ancient spaces and structures that are no longer existing or that were never constructed.

PIV Study of the Effect of Piston Motion on the Confined Swirling Flow in the Scavenging Process in 2-Stroke Marine Diesel Engines

DEFF Research Database (Denmark)

Haider, Sajjad; Meyer, Knud Erik; Schramm, Jesper

2010-01-01

The effect of piston motion on the incylinder swirling flow for a low speed, large two-stroke marine diesel engine is studies using the stereoscopic PIV technique. The measuremenrs are conducted at 5 cross sectional planes along the cylinder length and at piston positions covering the air intake...

Immersive Eating

DEFF Research Database (Denmark)

Korsgaard, Dannie Michael; Nilsson, Niels Chr.; Bjørner, Thomas

2017-01-01

This paper documents a pilot study evaluating a simple approach allowing users to eat real food while exploring a virtual environment (VE) through a head-mounted display (HMD). Two cameras mounted on the HMD allowed for video-based stereoscopic see-through when the user’s head orientation pointed...

IGLANCE: interactive free viewpoint for 3D TV

NARCIS (Netherlands)

Zinger, S.; Do, Q.L.; Ruijters, D.; With, de P.H.N.

2010-01-01

The iGLANCE project aims at making interactive free viewpoint selection possible in 3D TV broadcasted media. This means that the viewer can select and interactively change the viewpoint of a stereoscopic streamed video. The interactivity is enabled by broad-casting a number of video streams from

The Ring of Fire for in-Field Sport Aerodynamic Investigation

NARCIS (Netherlands)

Spoelstra, A.M.C.M.G.; Terra, W.; Sciacchitano, A.; Espinosa, Hugo G.; Rowlands, David R.; Shepherd, Jonathan; Thiel, David V.

2018-01-01

A novel measurement system, the Ring of Fire, is deployed which enables the aerodynamic drag estimation of transiting cyclists. The system relies upon the use of large-scale stereoscopic PIV and the conservation of momentum within a control volume in a frame of reference moving with the athlete. The

Multi-scale AM-FM for lesion phenotyping

NARCIS (Netherlands)

Barriga, E.S.; Murray, V.; Agurto, C.; Pattichis, M.S.; Russell, S.; Abramoff, M.D.; Davis, H.; Soliz, P.

2009-01-01

Age-related macular degeneration (AMD) is the most common cause of visual loss in the United States and is a growing public health problem. The presence and severity of AMD in current epidemiological studies is detected by the grading of color stereoscopic fundus photographs. The purpose of this

Three dimensional experimental investigation of a hypersonic double-ramp flow

NARCIS (Netherlands)

Schrijer, F.F.J.; Caljouw, R.; Scarano, F.; Van Oudheusden, B.W.

The flow over a 15?-45? double compression ramp was studied at Mach 7.5. CFD computations are compared to 2 component PIV (particle image velocimetry) measurements. Furthermore stereoscopic PIV was used to measure the three component velocity vector, enabling to perform a 3D flow survey. The overall

The Use of Haptic Display Technology in Education

Science.gov (United States)

Barfield, Woodrow

2009-01-01

The experience of "virtual reality" can consist of head-tracked and stereoscopic virtual worlds, spatialized sound, haptic feedback, and to a lesser extent olfactory cues. Although virtual reality systems have been proposed for numerous applications, the field of education is one particular application that seems well-suited for virtual…

Study on an Interactive Truck Crane Simulation Platform Based on Virtual Reality Technology

Science.gov (United States)

Sang, Yong; Zhu, Yu; Zhao, Honghua; Tang, Mingyan

2016-01-01

The modern web-based distance education overcomes space-time restriction of the traditional teaching forms. However, being short of specifically observable and operable experimental equipment makes the web-based education lack advantages in the knowledge learning progress, which needs strong stereoscopic effect and operability. Truck crane is the…

Effects of micro-ramps on a shock wave/turbulent boundary layer interaction

NARCIS (Netherlands)

Blinde, P.L.; Humble, R.A.; Van Oudheusden, B.W.; Scarano, F.

2009-01-01

Stereoscopic particle image velocimetry is used to investigate the effects of micro-ramp sub-boundary layer vortex generators, on an incident shock wave/boundary layer interaction at Mach 1.84. Single- and double-row arrangements of micro-ramps are considered. The micro-ramps have a height of 20% of

Flow structures in large-angle conical diffusers measured by PIV

DEFF Research Database (Denmark)

Meyer, Knud Erik; Nielsen, L.; Nielsen, N.F.

2004-01-01

Flow in two different conical diffusers with large opening angles (30° and 18°) have been measured with stereoscopic Particle Image Velocimetry (PIV). The measurements were done in a cross section just after the exit of the diffuser. The Reynolds number was 100000 based on upstream diameter...

Real-time three-dimensional soft tissue reconstruction for laparoscopic surgery.

Science.gov (United States)

Kowalczuk, Jędrzej; Meyer, Avishai; Carlson, Jay; Psota, Eric T; Buettner, Shelby; Pérez, Lance C; Farritor, Shane M; Oleynikov, Dmitry

2012-12-01

Accurate real-time 3D models of the operating field have the potential to enable augmented reality for endoscopic surgery. A new system is proposed to create real-time 3D models of the operating field that uses a custom miniaturized stereoscopic video camera attached to a laparoscope and an image-based reconstruction algorithm implemented on a graphics processing unit (GPU). The proposed system was evaluated in a porcine model that approximates the viewing conditions of in vivo surgery. To assess the quality of the models, a synthetic view of the operating field was produced by overlaying a color image on the reconstructed 3D model, and an image rendered from the 3D model was compared with a 2D image captured from the same view. Experiments conducted with an object of known geometry demonstrate that the system produces 3D models accurate to within 1.5 mm. The ability to produce accurate real-time 3D models of the operating field is a significant advancement toward augmented reality in minimally invasive surgery. An imaging system with this capability will potentially transform surgery by helping novice and expert surgeons alike to delineate variance in internal anatomy accurately.

In situ vocal fold properties and pitch prediction by dynamic actuation of the songbird syrinx

DEFF Research Database (Denmark)

Düring, Daniel N; Knörlein, Benjamin J; Elemans, Coen P H

2017-01-01

, forces and torques exerted on, and motion of the syringeal skeleton during song. Here, we present a novel marker-based 3D stereoscopic imaging technique to reconstruct 3D motion of servo-controlled actuation of syringeal muscle insertions sites in vitro and focus on two muscles controlling sound pitch...... to musculus syringealis ventralis (VS) shortening is intrinsically constraint at maximally 12% strain. Using these values we predict sound pitch to range from 350-800 Hz by VS modulation, corresponding well to previous observations. The presented methodology allows for quantification of syringeal skeleton...... motion and forces, acoustic effects of muscle recruitment, and calibration of computational birdsong models, enabling experimental access to the entire neuromechanical control loop of vocal motor control....

Software-Based Adjustment of Mobile Autostereoscopic Graphics Using Static Parallax Barriers

DEFF Research Database (Denmark)

Paprocki, Martin Marko; Krog, Kim Srirat; Kristoffersen, Morten Bak

2012-01-01

We show that the autostereoscopic display of stereoscopic images using a static parallax barrier can be improved by adapting the rendering to the angle under which the user is looking at a mobile display; thus, ghosting artifacts and depth reversals can often be avoided even if the user tilts the...

ReSOnJl1f.Ce iournal of science education

Indian Academy of Sciences (India)

Carl Hirschie Johnson. 32 Pittendrigh: The Darwinian Clock-Watcher. Vijay Kumar Sharma. 42 The 2005 Nobel Prize in Physics: Optics. Vasant Natarajan and N Mukunda. -. ~ 8 Aryabha~a and Axial Rotation of Earth. A Brief History. Amartya Kumar Dutta. RESEARCH NEWS. 73 Stereoscopic View of the Sun and its Adivity.

Bluff-body drag reduction using a deflector

Energy Technology Data Exchange (ETDEWEB)

Fourrie, Gregoire; Keirsbulck, Laurent; Labraga, Larbi [Univ Lille Nord de France, Lille (France); UVHC, TEMPO, Valenciennes (France); Gillieron, Patrick [Fluid Mechanics and Aerodynamics, Renault Group, Research Division, Guyancourt (France)

2011-02-15

A passive flow control on a generic car model was experimentally studied. This control consists of a deflector placed on the upper edge of the model rear window. The study was carried out in a wind tunnel at Reynolds numbers based on the model height of 3.1 x 10{sup 5} and 7.7 x 10{sup 5}. The flow was investigated via standard and stereoscopic particle image velocimetry, Kiel pressure probes and surface flow visualization. The aerodynamic drag was measured using an external balance and calculated using a wake survey method. Drag reductions up to 9% were obtained depending on the deflector angle. The deflector increases the separated region on the rear window. The results show that when this separated region is wide enough, it disrupts the development of the counter-rotating longitudinal vortices appearing on the lateral edges of the rear window. The current study suggests that flow control on such geometries should consider all the flow structures that contribute to the model wake flow. (orig.)

Correspondence of line segments between two perpective images ...

African Journals Online (AJOL)

In order to permit the localization and the navigation of a mobile robot within an interior environment, we have built a stereoscopic sensor and implemented all the algorithms which allow to obtain 3D coordinates of real objects from data images. Sensor uses two mini cameras with vertical disposition. Processing on the ...

UV and X-ray Variability of Blazars Alok C. Gupta

Indian Academy of Sciences (India)

mostly soft X-rays hardness ratio show correlations with blazar luminos- ity and different modes of variability might be operating for different time scales and ... The real cause of blazar variability on diverse time scales is not yet well under- stood. ... stereoscopic system (HESS) at a 45σ significance level (Aharonian et al.

Wow! 3D Content Awakens the Classroom

Science.gov (United States)

Gordon, Dan

2010-01-01

From her first encounter with stereoscopic 3D technology designed for classroom instruction, Megan Timme, principal at Hamilton Park Pacesetter Magnet School in Dallas, sensed it could be transformative. Last spring, when she began pilot-testing 3D content in her third-, fourth- and fifth-grade classrooms, Timme wasn't disappointed. Students…

3D CAPABILITIES OF PLEIADES SATELLITE

Directory of Open Access Journals (Sweden)

M. Bernard

2012-08-01

Full Text Available End of 2011 a new optical satellite, called Pléiades, was launched by the French space agency (CNES. It provides 20 km x 20 km images at 0.5 meters. This agile acquisition system is able to relocate very rapidly and scan the earth in any direction. The agility of the system offers the ability to acquire multi viewing angle images of the same area during the same orbit. This ability to capture, from a single stereoscopic pair, to a sequence of 25 images, allows enhancing the quality and the completeness of automatically extracted 3D maps. The aim of the study is to validate and quantify the capacity of the Pléiades system to perform 3D mapping. The analysis explores the advantages in terms of quality and automatism to use more than 2 stereoscopic images. In the last 10 years, automatic 3D processing of digital images became more and more popular and efficient. Thanks to aerial images with very large overlap and very high resolution satellite images, new methodologies and algorithms have been implemented to improve the quality and accuracy of automatic 3D processing. We propose to experiment the same type of approaches using Pléiades images to produce digital elevation models (DEM. A focus is made on analysing the 3D processing using video like (multi viewing acquisitions. Different reference sites with very accurate 3D control points are used to quantify the quality of the Pléiades DEM. Different acquisition modes are explored from a single stereo pair to a sequence of 17 images.

Bimanual Interaction with Interscopic Multi-Touch Surfaces

Science.gov (United States)

Schöning, Johannes; Steinicke, Frank; Krüger, Antonio; Hinrichs, Klaus; Valkov, Dimitar

Multi-touch interaction has received considerable attention in the last few years, in particular for natural two-dimensional (2D) interaction. However, many application areas deal with three-dimensional (3D) data and require intuitive 3D interaction techniques therefore. Indeed, virtual reality (VR) systems provide sophisticated 3D user interface, but then lack efficient 2D interaction, and are therefore rarely adopted by ordinary users or even by experts. Since multi-touch interfaces represent a good trade-off between intuitive, constrained interaction on a touch surface providing tangible feedback, and unrestricted natural interaction without any instrumentation, they have the potential to form the foundation of the next generation user interface for 2D as well as 3D interaction. In particular, stereoscopic display of 3D data provides an additional depth cue, but until now the challenges and limitations for multi-touch interaction in this context have not been considered. In this paper we present new multi-touch paradigms and interactions that combine both traditional 2D interaction and novel 3D interaction on a touch surface to form a new class of multi-touch systems, which we refer to as interscopic multi-touch surfaces (iMUTS). We discuss iMUTS-based user interfaces that support interaction with 2D content displayed in monoscopic mode and 3D content usually displayed stereoscopically. In order to underline the potential of the proposed iMUTS setup, we have developed and evaluated two example interaction metaphors for different domains. First, we present intuitive navigation techniques for virtual 3D city models, and then we describe a natural metaphor for deforming volumetric datasets in a medical context.

EEG-based cognitive load of processing events in 3D virtual worlds is lower than processing events in 2D displays.

Science.gov (United States)

Dan, Alex; Reiner, Miriam

2017-12-01

Interacting with 2D displays, such as computer screens, smartphones, and TV, is currently a part of our daily routine; however, our visual system is built for processing 3D worlds. We examined the cognitive load associated with a simple and a complex task of learning paper-folding (origami) by observing 2D or stereoscopic 3D displays. While connected to an electroencephalogram (EEG) system, participants watched a 2D video of an instructor demonstrating the paper-folding tasks, followed by a stereoscopic 3D projection of the same instructor (a digital avatar) illustrating identical tasks. We recorded the power of alpha and theta oscillations and calculated the cognitive load index (CLI) as the ratio of the average power of frontal theta (Fz.) and parietal alpha (Pz). The results showed a significantly higher cognitive load index associated with processing the 2D projection as compared to the 3D projection; additionally, changes in the average theta Fz power were larger for the 2D conditions as compared to the 3D conditions, while alpha average Pz power values were similar for 2D and 3D conditions for the less complex task and higher in the 3D state for the more complex task. The cognitive load index was lower for the easier task and higher for the more complex task in 2D and 3D. In addition, participants with lower spatial abilities benefited more from the 3D compared to the 2D display. These findings have implications for understanding cognitive processing associated with 2D and 3D worlds and for employing stereoscopic 3D technology over 2D displays in designing emerging virtual and augmented reality applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Capillaroscopy in diagnostic of systemic autoimmune diseases

International Nuclear Information System (INIS)

Garra, V.; Danese, N.; Rebella, M.

2012-01-01

The diagnosis of systemic autoimmune diseases is carried out by combining clinical, paraclinical, imaging and anatomopathological data. However, in many cases is necessary to access other guiding parameters. The capillaroscopy is a technique that consists in the observation of capillary microcirculation in the proximal nail fold hands. The methods used are the videocapillaroscopy (microscopy, stereoscopic)

Reduced Mental Load in Learning a Motor Visual Task with Virtual 3D Method

Science.gov (United States)

Dan, A.; Reiner, M.

2018-01-01

Distance learning is expanding rapidly, fueled by the novel technologies for shared recorded teaching sessions on the Web. Here, we ask whether 3D stereoscopic (3DS) virtual learning environment teaching sessions are more compelling than typical two-dimensional (2D) video sessions and whether this type of teaching results in superior learning. The…

Using Smartphone Camera Technology to Explore Stellar Parallax: Method, Results, and Reactions

Science.gov (United States)

Fitzgerald, Michael T.; McKinnon, David H.; Danaia, Lena; Woodward, Sandra

2011-01-01

Stellar parallax is a concept that is dealt with infrequently in the high school classroom other than by qualitative consideration of stereoscopic parallax and argument by analogy. Use of stellar parallax for distance determination can be difficult for students to understand without some type of hands-on experience to explore the concept. Thus,…

Analysis of Display Latency for 3D Perceptual Experiments

Science.gov (United States)

2016-11-01

Stereoscopic images were displayed on an LG 55 in. Class (54.6 in. diagonal) cinema 3D 1080p 240 Hz LED TV for stimulus display. The 3D display...were nearly identical to those in Recording 3, where we had the variation in stimulus depth and the randomly sampled ISI times. The camera position

Remote operation: a selective review of research into visual depth perception.

Science.gov (United States)

Reinhardt-Rutland, A H

1996-07-01

Some perceptual motor operations are performed remotely; examples include the handling of life-threatening materials and surgical procedures. A camera conveys the site of operation to a TV monitor, so depth perception relies mainly on pictorial information, perhaps with enhancement of the occlusion cue by motion. However, motion information such as motion parallax is not likely to be important. The effectiveness of pictorial information is diminished by monocular and binocular information conveying flatness of the screen and by difficulties in scaling: Only a degree of relative depth can be conveyed. Furthermore, pictorial information can mislead. Depth perception is probably adequate in remote operation, if target objects are well separated, with well-defined edges and familiar shapes. Stereoscopic viewing systems are being developed to introduce binocular information to remote operation. However, stereoscopic viewing is problematic because binocular disparity conflicts with convergence and monocular information. An alternative strategy to improve precision in remote operation may be to rely on individuals who lack binocular function: There is redundancy in depth information, and such individuals seem to compensate for the lack of binocular function.

Data-processing system for bubble-chamber photographs based on PUOS-4 measuring projectors and an ES-1045 computer

International Nuclear Information System (INIS)

Ermolov, P.F.; Kozlov, V.V.; Rukovichkin, V.P.

1988-01-01

A system is described that was developed at the Scientific-Research Institute of Nuclear Physics for processing of the data recorded on stereoscopic photographs from large bubble chambers and hybrid spectrometers using PUOS-4 measuring projectors, an Elektronika-60 microcomputer, and an ES-1045 computer. The system structure, the main programmable interfaces, and the intercomputer communications are examined. The mean-square error of the measuring channels of the system, determined from calibration measurements, is within 1.3-3.5 μm; the standard deviation of the coordinates of the measured points with respect to the track in the plane of the photograph is 6 μm. The system is widely used at the institute for analysis of data from experiments in high-energy physics performed with the European Hybrid Spectrometer and the Mirabel large bubble chamber. Approximately 80,000 stereoscopic photographs have been processed and the system is being prepared to process data from the Skat bubble chamber and a spectrometer with a vertex detector that is under construction

Case study: Beauty and the Beast 3D: benefits of 3D viewing for 2D to 3D conversion

Science.gov (United States)

Handy Turner, Tara

2010-02-01

From the earliest stages of the Beauty and the Beast 3D conversion project, the advantages of accurate desk-side 3D viewing was evident. While designing and testing the 2D to 3D conversion process, the engineering team at Walt Disney Animation Studios proposed a 3D viewing configuration that not only allowed artists to "compose" stereoscopic 3D but also improved efficiency by allowing artists to instantly detect which image features were essential to the stereoscopic appeal of a shot and which features had minimal or even negative impact. At a time when few commercial 3D monitors were available and few software packages provided 3D desk-side output, the team designed their own prototype devices and collaborated with vendors to create a "3D composing" workstation. This paper outlines the display technologies explored, final choices made for Beauty and the Beast 3D, wish-lists for future development and a few rules of thumb for composing compelling 2D to 3D conversions.

Multi-layered see-through movie in diminished reality

Science.gov (United States)

Uematsu, Yuko; Hashimoto, Takanori; Inoue, Takuya; Shimizu, Naoki; Saito, Hideo

2012-03-01

This paper presents generating a multi-layered see-through movie for an auto-stereoscopic display. This work is based on Diminished Reality (DR), which is one of the research fields of Augmented Reality (AR). In the usual AR, some virtual objects are added on the real world. On the other hand, DR removes some real objects from the real world. Therefore, the background is visualized instead of the real objects (obstacles) to be removed. We use multiple color cameras and one TOF depth camera. The areas of obstacles are defined by using the depth camera based on the distance of obstacles. The background behind the obstacles is recovered by planarprojection of multiple cameras. Then, the recovered background is overlaid onto the removed obstacles. For visualizing it through the auto-stereoscopic display, the scene is divided into multiple layers such as obstacles and background. The pixels corresponding to the obstacles are not visualized or visualized semi-transparently at the center viewpoints. Therefore, we can see that the obstacles are diminished according to the viewpoints.

Autostereoscopic three-dimensional display by combining a single spatial light modulator and a zero-order nulled grating

Science.gov (United States)

Su, Yanfeng; Cai, Zhijian; Liu, Quan; Lu, Yifan; Guo, Peiliang; Shi, Lingyan; Wu, Jianhong

2018-04-01

In this paper, an autostereoscopic three-dimensional (3D) display system based on synthetic hologram reconstruction is proposed and implemented. The system uses a single phase-only spatial light modulator to load the synthetic hologram of the left and right stereo images, and the parallax angle between two reconstructed stereo images is enlarged by a grating to meet the split angle requirement of normal stereoscopic vision. To realize the crosstalk-free autostereoscopic 3D display with high light utilization efficiency, the groove parameters of the grating are specifically designed by the rigorous coupled-wave theory for suppressing the zero-order diffraction, and then the zero-order nulled grating is fabricated by the holographic lithography and the ion beam etching. Furthermore, the diffraction efficiency of the fabricated grating is measured under the illumination of a laser beam with a wavelength of 532 nm. Finally, the experimental verification system for the proposed autostereoscopic 3D display is presented. The experimental results prove that the proposed system is able to generate stereoscopic 3D images with good performances.

Video stereolization: combining motion analysis with user interaction.

Science.gov (United States)

Liao, Miao; Gao, Jizhou; Yang, Ruigang; Gong, Minglun

2012-07-01

We present a semiautomatic system that converts conventional videos into stereoscopic videos by combining motion analysis with user interaction, aiming to transfer as much as possible labeling work from the user to the computer. In addition to the widely used structure from motion (SFM) techniques, we develop two new methods that analyze the optical flow to provide additional qualitative depth constraints. They remove the camera movement restriction imposed by SFM so that general motions can be used in scene depth estimation-the central problem in mono-to-stereo conversion. With these algorithms, the user's labeling task is significantly simplified. We further developed a quadratic programming approach to incorporate both quantitative depth and qualitative depth (such as these from user scribbling) to recover dense depth maps for all frames, from which stereoscopic view can be synthesized. In addition to visual results, we present user study results showing that our approach is more intuitive and less labor intensive, while producing 3D effect comparable to that from current state-of-the-art interactive algorithms.

Transparency in stereopsis: parallel encoding of overlapping depth planes.

Science.gov (United States)

Reeves, Adam; Lynch, David

2017-08-01

We report that after extensive training, expert adults can accurately report the number, up to six, of transparent overlapping depth planes portrayed by brief (400 ms or 200 ms) random-element stereoscopic displays, and can well discriminate six from seven planes. Naïve subjects did poorly above three planes. Displays contained seven rows of 12 randomly located ×'s or +'s; jittering the disparities and number in each row to remove spurious cues had little effect on accuracy. Removing the central 3° of the 10° display to eliminate foveal vision hardly reduced the number of reportable planes. Experts could report how many of six planes contained +'s when the remainder contained ×'s, and most learned to report up to six planes in reverse contrast (left eye white +'s; right eye black +'s). Long-term training allowed some experts to reach eight depth planes. Results suggest that adult stereoscopic vision can learn to distinguish the outputs of six or more statistically independent, contrast-insensitive, narrowly tuned, asymmetric disparity channels in parallel.

Stereoscopic and photometric surface reconstruction in scanning electron microscopy

International Nuclear Information System (INIS)

Scherer, S.

2000-01-01

The scanning electron microscope (SEM) is one of the most important devices to examine microscopic structures as it offers images of a high contrast range with a large depth of focus. Nevertheless, three-dimensional measurements, as desired in fracture mechanics, have previously not been accomplished. This work presents a system for automatic, robust and dense surface reconstruction in scanning electron microscopy combining new approaches in shape from stereo and shape from photometric stereo. The basic theoretical assumption for a known adaptive window algorithm is shown not to hold in scanning electron microscopy. A constraint derived from this observation yields a new, simplified, hence faster calculation of the adaptive window. The correlation measure itself is obtained by a new ordinal measure coefficient. Shape from photometric stereo in the SEM is formulated by relating the image formation process with conventional photography. An iterative photometric ratio reconstruction is invented based on photometric ratios of backscatter electron images. The performance of the proposed system is evaluated using ground truth data obtained by three alternative shape recovery devices. Most experiments showed relative height accuracy within the tolerances of the alternative devices. (author)

Full aperture imaging with stereoscopic properties in nuclear medicine

International Nuclear Information System (INIS)

Strocovsky, Sergio G.; Otero, D.

2011-01-01

The imaging techniques based on gamma camera (CG) and used in nuclear medicine have low spatial resolution and low sensitivity due to the use of the collimator. However, this element is essential for the formation of images in CG. The aim of this work is to show the principles of a new technique to overcome the limitations of existing techniques based on CG. Here, we present a Full Aperture Imaging (FAI) technique which is based on the edge-encoding of gamma radiation and differential detection. It takes advantage of the fact that gamma radiation is spatially incoherent. The mathematical principles and the method of images reconstruction with the new proposed technique are explained in detail. The FAI technique is tested by means of Monte Carlo simulations with filiform and spherical sources. The results show that FAI technique has greater sensitivity (>100 times) and greater spatial resolution (>2.6 times) than that of GC with LEHR collimator, in both cases, with and without attenuating material and long and short-distance configurations. The FAI decoding algorithm reconstructs simultaneously four different projections which are located in separate image fields on the detector plane, while GC produces only one projection per acquisition. Simulations have allowed comparison of both techniques under ideal identical conditions. Our results show it is possible to apply an extremely simple encoded imaging technique, and get three-dimensional radioactivity information for simplistic geometry sources. The results are promising enough to evaluate the possibility of future research with more complex sources typical of nuclear medicine imaging. (author)

Optimal Backlight Modulation With Crosstalk Control in Stereoscopic Display

DEFF Research Database (Denmark)

Jiao, Liangbao; Shu, Xiao; Cheng, Yong

2014-01-01

. A simple closed-form approximation of the optimization problem can be easily employed and solved in real time on LCD control hardware. Simulation results show that the proposed OBM algorithm provides the same or higher luminance while reducing the crosstalk by 60% compared with the other tested methods....

A teleoperation training simulator with visual and kinesthetic force virtual reality

Science.gov (United States)

Kim, Won S.; Schenker, Paul

1992-01-01

A force-reflecting teleoperation training simulator with a high-fidelity real-time graphics display has been developed for operator training. A novel feature of this simulator is that it enables the operator to feel contact forces and torques through a force-reflecting controller during the execution of the simulated peg-in-hole task, providing the operator with the feel of visual and kinesthetic force virtual reality. A peg-in-hole task is used in our simulated teleoperation trainer as a generic teleoperation task. A quasi-static analysis of a two-dimensional peg-in-hole task model has been extended to a three-dimensional model analysis to compute contact forces and torques for a virtual realization of kinesthetic force feedback. The simulator allows the user to specify force reflection gains and stiffness (compliance) values of the manipulator hand for both the three translational and the three rotational axes in Cartesian space. Three viewing modes are provided for graphics display: single view, two split views, and stereoscopic view.

Impact of internal bremsstrahlung on the detection of γ rays from neutralinos

International Nuclear Information System (INIS)

Cannoni, M.; Gomez, M. E.; Sanchez-Conde, M. A.; Prada, F.; Panella, O.

2010-01-01

We present a detailed study of the effect of internal bremsstrahlung photons in the context of the minimal supersymmetric standard models and their impact on γ-ray dark matter annihilation searches. We find that, although this effect has to be included for the correct evaluation of fluxes of high energy photons from neutralino annihilation, its contribution is relevant only in models and at energies where the lines contribution is dominant over the secondary photons. Therefore, we find that the most optimistic supersymmetric scenarios for dark matter detection do not change significantly when including the internal bremsstrahlung. As an example, we review the γ-ray dark matter detection prospects of the Draco dwarf spheroidal galaxy for the MAGIC stereoscopic system and the CTA project. Though the flux of high energy photons is enhanced by an order of magnitude in some regions of the parameter space, the expected fluxes are still much below the sensitivity of the instruments.

Cognitive Load and Attentional Demands during Objects' Position Change in Real and Digital Environments

Science.gov (United States)

Zacharis, Georgios K.; Mikropoulos, Tassos Anastasios; Kalyvioti, Katerina

2016-01-01

Studies showed that two-dimensional (2D) and three-dimensional (3D) educational content contributes to learning. Although there were many studies with 3D stereoscopic learning environments, only a few studies reported on the differences between real, 2D, and 3D scenes, as far as cognitive load and attentional demands were concerned. We used…

A Simple, Low-Cost Stereographic Video Capture and Viewing Solution for Teaching Psychomotor Skills Using Online Delivery

Science.gov (United States)

White, Ian

2010-01-01

It is recognised that the teaching of complex psychomotor skills using online delivery is difficult without the support of either face-to-face coaching and tuition or a stereoscopic viewing system that provides users with a feel for the spatial nature of the skills being taught. To date, the limitations of bandwidth, and the high cost and…

Automatic online and real-time tumour motion monitoring during stereotactic liver treatments on a conventional linac by combined optical and sparse monoscopic imaging with kilovoltage x-rays (COSMIK)

Science.gov (United States)

Bertholet, Jenny; Toftegaard, Jakob; Hansen, Rune; Worm, Esben S.; Wan, Hanlin; Parikh, Parag J.; Weber, Britta; Høyer, Morten; Poulsen, Per R.

2018-03-01

The purpose of this study was to develop, validate and clinically demonstrate fully automatic tumour motion monitoring on a conventional linear accelerator by combined optical and sparse monoscopic imaging with kilovoltage x-rays (COSMIK). COSMIK combines auto-segmentation of implanted fiducial markers in cone-beam computed tomography (CBCT) projections and intra-treatment kV images with simultaneous streaming of an external motion signal. A pre-treatment CBCT is acquired with simultaneous recording of the motion of an external marker block on the abdomen. The 3-dimensional (3D) marker motion during the CBCT is estimated from the auto-segmented positions in the projections and used to optimize an external correlation model (ECM) of internal motion as a function of external motion. During treatment, the ECM estimates the internal motion from the external motion at 20 Hz. KV images are acquired every 3 s, auto-segmented, and used to update the ECM for baseline shifts between internal and external motion. The COSMIK method was validated using Calypso-recorded internal tumour motion with simultaneous camera-recorded external motion for 15 liver stereotactic body radiotherapy (SBRT) patients. The validation included phantom experiments and simulations hereof for 12 fractions and further simulations for 42 fractions. The simulations compared the accuracy of COSMIK with ECM-based monitoring without model updates and with model updates based on stereoscopic imaging as well as continuous kilovoltage intrafraction monitoring (KIM) at 10 Hz without an external signal. Clinical real-time tumour motion monitoring with COSMIK was performed offline for 14 liver SBRT patients (41 fractions) and online for one patient (two fractions). The mean 3D root-mean-square error for the four monitoring methods was 1.61 mm (COSMIK), 2.31 mm (ECM without updates), 1.49 mm (ECM with stereoscopic updates) and 0.75 mm (KIM). COSMIK is the first combined kV/optical real-time motion

Evidence for inhomogeneous thermal sources of two spike events of 1978, May 5 and December 4

International Nuclear Information System (INIS)

Wiehl, H.J.; Desai, U.

1982-09-01

Two short duration single spike events of 1978 May 5 and December 4 exhibit similar time profiles in the microwave and hard X-ray ranges, indicating emission from compact sources. Microwave spectral observations exhibit inhomogeneieties present in the source parameters. The existence of fine time structures in the microwave time profiles at 10.4 GHz from Berne are interpreted as a signature of the dynamics of a disturbance travelling through the souce at the ion-sound speed. Stereoscopic observations with the hard X-ray detector on the solar orbiter, Helios-2, and the Berne microwave antennae do not indicate any time lag or differences in the time profiles during the impulsive phase. This is taken as evidence for the absence of directionality of emission making beam models unlikely for short duration single spike events

Near wall turbulence: An experimental view

Science.gov (United States)

Stanislas, Michel

2017-10-01

The present paper draws upon the experience of the author to illustrate the potential of advanced optical metrology for understanding near-wall-turbulence physics. First the canonical flat plate boundary layer problem is addressed, initially very near to the wall and then in the outer region when the Reynolds number is high enough to generate an outer turbulence peak. The coherent structure organization is examined in detail with the help of stereoscopic particle image velocimetry (PIV). Then the case of a turbulent boundary layer subjected to a mild adverse pressure gradient is considered. The results obtained show the great potential of a joint experimental-numerical approach. The conclusion is that the insight provided by today's optical metrology opens the way for significant improvements in turbulence modeling in upcoming years.

Image Based Biomarker of Breast Cancer Risk: Analysis of Risk Disparity Among Minority Populations

Science.gov (United States)

2014-03-01

cluster locations. In the undirected strategy, the PDF is uniform within the entire volume of the breast , while in...stereoscopic breast biopsy images (13, 14). Each cluster in the database is stored as a 3D binary volume, with a voxel value of ‘1’ representing...AD_________________ Award Number: W81XWH-09-1-0062 TITLE: Image Based Biomarker of Breast Cancer

Student production: making a realistic stereo CG short film in six months

Science.gov (United States)

Ramasamy, Celambarasan

2010-02-01

This paper breaks down the R&D and production challenges faced on a stereoscopic CG short film that was developed on a six month time budget. Using this film as an example, the manner in which technical innovation and story telling techniques can be used to emphasize the strengths and hide the weaknesses of a limited timeframe student production is discussed.

Three-dimensional views of the nucleus of Comet 67P/Churyumov-Gerasimenko: an atlas of stereo anaglyphs from OSIRIS-NAC images

Science.gov (United States)

Lamy, Philippe L.; Romeuf, David; Faury, Guillaume; Durand, Joelle; Beigbeder, Laurent; Groussin, Olivier

2017-10-01

The Narrow Angle Camera (NAC) of the OSIRIS imaging system aboard ESA’s Rosetta spacecraft has acquired approximately 25000 images of the surface of the nucleus of comet 67P/Churyumov-Gerasimenko at various spatial scales down to centimeters per pixel. The bulk of these images have been obtained in sequences and the combined displacement of the Rosetta orbiter along its trajectory and the rotation of the nucleus allow associating many pairs of images appropriate to stereoscopic viewing. This is achieved by constructing anaglyphs after rotating the images so that the relative shift appears horizontal. The shift is set to limit the parallax to approximately 2° (with a maximum value of 4°) for the foreground (to avoid image deformation) and the scene is placed behind the screen for optimal visual comfort. The rotation of the nucleus may have the adverse effect of introducing temporal incoherence, prominently from the variation of the cast shadows. Various solutions are implemented to circumvent this problem, usually by cropping the maximum extent of the shadows. A time of writing, approximately 900 anaglyphs have been produced and we expect to reach several thousand once the systematic search of suitable pairs will be completed. We will present examples of anaglyphs. They will be searchable thanks to a dedicated data base that will document each one including its location on a 3D numerical model of the nucleus. Many possibilities of querying the parameters will be offered. It is anticipated that this atlas available online in the near future will be a valuable tool for fostering our understanding of the complex morphology of the cometary surface and of the processes at work , as well as offering spectacular stereoscopic views of the nucleus enjoyable by a general public.

Design of an experimental four-camera setup for enhanced 3D surface reconstruction in microsurgery

Directory of Open Access Journals (Sweden)

Marzi Christian

2017-09-01

Full Text Available Future fully digital surgical visualization systems enable a wide range of new options. Caused by optomechanical limitations a main disadvantage of today’s surgical microscopes is their incapability of providing arbitrary perspectives to more than two observers. In a fully digital microscopic system, multiple arbitrary views can be generated from a 3D reconstruction. Modern surgical microscopes allow replacing the eyepieces by cameras in order to record stereoscopic videos. A reconstruction from these videos can only contain the amount of detail the recording camera system gathers from the scene. Therefore, covered surfaces can result in a faulty reconstruction for deviating stereoscopic perspectives. By adding cameras recording the object from different angles, additional information of the scene is acquired, allowing to improve the reconstruction. Our approach is to use a fixed four-camera setup as a front-end system to capture enhanced 3D topography of a pseudo-surgical scene. This experimental setup would provide images for the reconstruction algorithms and generation of multiple observing stereo perspectives. The concept of the designed setup is based on the common main objective (CMO principle of current surgical microscopes. These systems are well established and optically mature. Furthermore, the CMO principle allows a more compact design and a lowered effort in calibration than cameras with separate optics. Behind the CMO four pupils separate the four channels which are recorded by one camera each. The designed system captures an area of approximately 28mm × 28mm with four cameras. Thus, allowing to process images of 6 different stereo perspectives. In order to verify the setup, it is modelled in silico. It can be used in further studies to test algorithms for 3D reconstruction from up to four perspectives and provide information about the impact of additionally recorded perspectives on the enhancement of a reconstruction.

Three-dimensional image capturing and representation for multimedia ambiance communication

Science.gov (United States)

Ichikawa, Tadashi; Iwasawa, Shoichiro; Yamada, Kunio; Kanamaru, Toshifumi; Naemura, Takeshi; Aizawa, Kiyoharu; Morishima, Shigeo; Saito, Takahiro

2001-02-01

Multimedia Ambiance Communication is as a means of achieving shared-space communication in an immersive environment consisting of an arch-type stereoscopic projection display. Our goal is to enable shared-space communication by creating a photo-realistic three-dimensional (3D) image space that users can feel a part of. The concept of a layered structure defined for painting, such as long-range, mid-range, and short-range views, can be applied to a 3D image space. New techniques, such as two-plane expression, high quality panorama image generation and setting representation for image processing, 3D image representation and generation for photo- realistic 3D image space have been developed. Also, we propose a life-like avatar within the 3D image space. To obtain the characteristics of user's body, a human subject is scanned using a CyberwareTM whole body scanner. The output from the scanner, a range image, is a good start for modeling the avatar's geometric shape. A generic human surface model is fitted to the range image. The obtained model is topologically equivalent even if our method is applied to another subject. If a generic model with motion definitions is employed, and common motion rules can be applied to all models made from the generic model.

Sum-Trigger-II status and prospective physics

Energy Technology Data Exchange (ETDEWEB)

Dazzi, Francesco; Mirzoyan, Razmik; Schweizer, Thomas; Teshima, Masahiro [Max Planck Institut fuer Physik, Munich (Germany); Herranz, Diego; Lopez, Marcos [Universidad Complutense, Madrid (Spain); Mariotti, Mose [Universita degli Studi di Padova (Italy); Nakajima, Daisuke [The University of Tokio (Japan); Rodriguez Garcia, Jezabel [Max Planck Institut fuer Physik, Munich (Germany); Instituto Astrofisico de Canarias, Tenerife (Spain)

2015-07-01

MAGIC is a stereoscopic system of 2 Imaging Air Cherenkov Telescopes (IACTs) for very high energy gamma-ray astronomy, located at La Palma (Spain). Lowering the energy threshold of IACTs is crucial for the observation of Pulsars, high redshift AGNs and GRBs. A novel trigger strategy, based on the analogue sum of a patch of pixels, can lead to a lower threshold compared to conventional digital triggers. In the last years, a major upgrade of the MAGIC telescopes took place in order to optimize the performances, mainly in the low energy domain. The PMTs camera and the reflective surface of MAGIC-I, as well as both readout systems, have been deeply renovated. The last important milestone is the implementation of a new stereoscopic analogue trigger, dubbed Sum-Trigger-II. The installation successfully ended in 2014 and the first data set has been already taken. Currently the fine-tuning of the main parameters as well as the comparison with Monte Carlo studies is ongoing. In this talk the status of Sum-Trigger-II and the future prospective physics cases at very low energy are presented.

The effects of gender, flow and video game experience on combat identification training.

Science.gov (United States)

Plummer, John Paul; Schuster, David; Keebler, Joseph R

2017-08-01

The present study examined the effects of gender, video game experience (VGE), and flow state on multiple indices of combat identification (CID) performance. Individuals were trained on six combat vehicles in a simulation, presented through either a stereoscopic or non-stereoscopic display. Participants then reported flow state, VGE and were tested on their ability to discriminate friend vs. foe and identify both pictures and videos of the trained vehicles. The effect of stereoscopy was not significant. There was an effect of gender across three dependent measures. For the two picture-based measures, the effect of gender was mediated by VGE. Additionally, the effect of gender was moderated by flow state on the identification measures. Overall, the study suggests that gender differences may be overcome by VGE and by achieving flow state. Selection based on these individual differences may be useful for future military simulation. Practitioner Summary: This work investigates the effect of gender, VGE and flow state on CID performance. For three measures of performance, there was a main effect of gender. Gender was mediated by previous VGE on two measures, and gender was moderated by flow state on two measures.

Visually representing reality: aesthetics and accessibility aspects

Science.gov (United States)

van Nes, Floris L.

2009-02-01

This paper gives an overview of the visual representation of reality with three imaging technologies: painting, photography and electronic imaging. The contribution of the important image aspects, called dimensions hereafter, such as color, fine detail and total image size, to the degree of reality and aesthetic value of the rendered image are described for each of these technologies. Whereas quite a few of these dimensions - or approximations, or even only suggestions thereof - were already present in prehistoric paintings, apparent motion and true stereoscopic vision only recently were added - unfortunately also introducing accessibility and image safety issues. Efforts are made to reduce the incidence of undesirable biomedical effects such as photosensitive seizures (PSS), visually induced motion sickness (VIMS), and visual fatigue from stereoscopic images (VFSI) by international standardization of the image parameters to be avoided by image providers and display manufacturers. The history of this type of standardization, from an International Workshop Agreement to a strategy for accomplishing effective international standardization by ISO, is treated at some length. One of the difficulties to be mastered in this process is the reconciliation of the, sometimes opposing, interests of vulnerable persons, thrill-seeking viewers, creative video designers and the game industry.

An innovative virtual reality training tool for orthognathic surgery.

Science.gov (United States)

Pulijala, Y; Ma, M; Pears, M; Peebles, D; Ayoub, A

2018-02-01

Virtual reality (VR) surgery using Oculus Rift and Leap Motion devices is a multi-sensory, holistic surgical training experience. A multimedia combination including 360° videos, three-dimensional interaction, and stereoscopic videos in VR has been developed to enable trainees to experience a realistic surgery environment. The innovation allows trainees to interact with the individual components of the maxillofacial anatomy and apply surgical instruments while watching close-up stereoscopic three-dimensional videos of the surgery. In this study, a novel training tool for Le Fort I osteotomy based on immersive virtual reality (iVR) was developed and validated. Seven consultant oral and maxillofacial surgeons evaluated the application for face and content validity. Using a structured assessment process, the surgeons commented on the content of the developed training tool, its realism and usability, and the applicability of VR surgery for orthognathic surgical training. The results confirmed the clinical applicability of VR for delivering training in orthognathic surgery. Modifications were suggested to improve the user experience and interactions with the surgical instruments. This training tool is ready for testing with surgical trainees. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Interobserver variability of radiation therapists aligning to fiducial markers for prostate radiation therapy

International Nuclear Information System (INIS)

Deegan, Timothy; Owen, Rebecca; Holt, Tanya; Roberts, Lisa; Biggs, Jennifer; McCarthy, Alicia; Parfitt, Matthew; Fielding, Andrew

2013-01-01

As the use of fiducial markers (FMs) for the localisation of the prostate during external beam radiation therapy (EBRT) has become part of routine practice, radiation therapists (RTs) have become increasingly responsible for online image interpretation. The aim of this investigation was to quantify the limits of agreement (LoA) between RTs when localising to FMs with orthogonal kilovoltage (kV) imaging. Six patients receiving prostate EBRT utilising FMs were included in this study. Treatment localisation was performed using kV imaging prior to each fraction. Online stereoscopic assessment of FMs, performed by the treating RTs, was compared with the offline assessment by three RTs. Observer agreement was determined by pairwise Bland-Altman analysis. Stereoscopic analysis of 225 image pairs was performed online at the time of treatment, and offline by three RT observers. Eighteen pairwise Bland-Altman analyses were completed to assess the level of agreement between observers. Localisation by RTs was found to be within clinically acceptable 95% LoAs. Small differences between RTs, in both the online and offline setting, were found to be within clinically acceptable limits. RTs were able to make consistent and reliable judgements when matching FMs on planar kV imaging.

Virtual environments for scene of crime reconstruction and analysis

Science.gov (United States)

Howard, Toby L. J.; Murta, Alan D.; Gibson, Simon

2000-02-01

This paper describes research conducted in collaboration with Greater Manchester Police (UK), to evalute the utility of Virtual Environments for scene of crime analysis, forensic investigation, and law enforcement briefing and training. We present an illustrated case study of the construction of a high-fidelity virtual environment, intended to match a particular real-life crime scene as closely as possible. We describe and evaluate the combination of several approaches including: the use of the Manchester Scene Description Language for constructing complex geometrical models; the application of a radiosity rendering algorithm with several novel features based on human perceptual consideration; texture extraction from forensic photography; and experiments with interactive walkthroughs and large-screen stereoscopic display of the virtual environment implemented using the MAVERIK system. We also discuss the potential applications of Virtual Environment techniques in the Law Enforcement and Forensic communities.

Particle image and acoustic Doppler velocimetry analysis of a cross-flow turbine wake

Science.gov (United States)

Strom, Benjamin; Brunton, Steven; Polagye, Brian

2017-11-01

Cross-flow turbines have advantageous properties for converting kinetic energy in wind and water currents to rotational mechanical energy and subsequently electrical power. A thorough understanding of cross-flow turbine wakes aids understanding of rotor flow physics, assists geometric array design, and informs control strategies for individual turbines in arrays. In this work, the wake physics of a scale model cross-flow turbine are investigated experimentally. Three-component velocity measurements are taken downstream of a two-bladed turbine in a recirculating water channel. Time-resolved stereoscopic particle image and acoustic Doppler velocimetry are compared for planes normal to and distributed along the turbine rotational axis. Wake features are described using proper orthogonal decomposition, dynamic mode decomposition, and the finite-time Lyapunov exponent. Consequences for downstream turbine placement are discussed in conjunction with two-turbine array experiments.

Pulsatile turbulent flow through pipe bends at high Dean and Womersley numbers

Science.gov (United States)

Kalpakli, Athanasia; Örlü, Ramis; Tillmark, Nils; Alfredsson, P. Henrik

2011-12-01

Turbulent pulsatile flows through pipe bends are prevalent in internal combustion engine components which consist of bent pipe sections and branching conduits. Nonetheless, most of the studies related to pulsatile flows in pipe bends focus on incompressible, low Womersley and low Dean number flows, primarily because they aim in modeling blood flow, while internal combustion engine related flows have mainly been addressed in terms of integral quantities and consist of single point measurements. The present study aims at bridging the gap between these two fields by means of time-resolved stereoscopic particle image velocimetry measurements in a pipe bend with conditions that are close to those encountered in exhaust manifolds. The time/phase-resolved three-dimensional cross-sectional flow-field 3 pipe diameters downstream the pipe bend is captured and the interplay between different secondary motions throughout a pulse cycle is discussed.

Pulsatile turbulent flow through pipe bends at high Dean and Womersley numbers

International Nuclear Information System (INIS)

Kalpakli, Athanasia; Örlü, Ramis; Tillmark, Nils; Alfredsson, P Henrik

2011-01-01

Turbulent pulsatile flows through pipe bends are prevalent in internal combustion engine components which consist of bent pipe sections and branching conduits. Nonetheless, most of the studies related to pulsatile flows in pipe bends focus on incompressible, low Womersley and low Dean number flows, primarily because they aim in modeling blood flow, while internal combustion engine related flows have mainly been addressed in terms of integral quantities and consist of single point measurements. The present study aims at bridging the gap between these two fields by means of time-resolved stereoscopic particle image velocimetry measurements in a pipe bend with conditions that are close to those encountered in exhaust manifolds. The time/phase-resolved three-dimensional cross-sectional flow-field 3 pipe diameters downstream the pipe bend is captured and the interplay between different secondary motions throughout a pulse cycle is discussed.

The 3-D solar radioastronomy and the structure of the corona and the solar wind. [solar probes of solar activity

Science.gov (United States)

Steinberg, J. L.; Caroubalos, C.

1976-01-01

The mechanism causing solar radio bursts (1 and 111) is examined. It is proposed that a nonthermal energy source is responsible for the bursts; nonthermal energy is converted into electromagnetic energy. The advantages are examined for an out-of-the-ecliptic solar probe mission, which is proposed as a means of stereoscopically viewing solar radio bursts, solar magnetic fields, coronal structure, and the solar wind.

Scintigraphic and echographic thyroid image matching by a stereoscopic method

International Nuclear Information System (INIS)

Ballet, E.; Rousseau, J.; Marchandise, X.; Cussac, J.F.; Ballet, E.; Vasseur, C.; Gibon, D.

1997-01-01

We developed a device which allows us to match echographic data and scintiscanning data in a common 3D reference system. In thyroid exploration, this device completes the nuclear medicine examination by specifying simultaneously volume and echo-structure of the gland. Positions of γ-camera and echograph are determined in a 3D reference system using the stereo-vision principle: two CCD cameras allow locating of both sensors within 1.6 m, and sensors may be moved in a 0.4 m x 0.4 m FOV. Real time computation is reduced by limiting data to be treated to light emitters landmarks mounted on the sensor and used to calculate its position and its orientation. Matching accuracy is better than 0.5 mm for position, and better than 0.35 deg for orientation. Sensor marking average time is lesser than 0.5 s. (authors)

Stereoscopic PIV measurement of boundary layer affected by DBD actuator

Directory of Open Access Journals (Sweden)

Procházka Pavel

2016-01-01

Full Text Available The effect of ionic wind generated by plasma actuator on developed boundary layer inside a narrow channel was investigated recently. Since the main investigated plane was parallel to the channel axis, the description of flow field was not evaluated credibly. This paper is dealing with cross-section planes downstream the actuator measured via 3D time-resolved PIV. The actuator position is in spanwise or in streamwise orientation so that ionic wind is blown in the same direction as the main flow or in opposite direction or perpendicularly. The interaction between boundary layer and ionic wind is evaluated for three different velocities of main flow and several parameters of plasma actuation (steady and unsteady regime, frequency etc.. Statistical properties of the flow are shown as well as dynamical behaviour of arising longitudinal vortices are discussed via phase-locked measurement and decomposition method.

Magnitude, precision, and realism of depth perception in stereoscopic vision.

Science.gov (United States)

Hibbard, Paul B; Haines, Alice E; Hornsey, Rebecca L

2017-01-01

Our perception of depth is substantially enhanced by the fact that we have binocular vision. This provides us with more precise and accurate estimates of depth and an improved qualitative appreciation of the three-dimensional (3D) shapes and positions of objects. We assessed the link between these quantitative and qualitative aspects of 3D vision. Specifically, we wished to determine whether the realism of apparent depth from binocular cues is associated with the magnitude or precision of perceived depth and the degree of binocular fusion. We presented participants with stereograms containing randomly positioned circles and measured how the magnitude, realism, and precision of depth perception varied with the size of the disparities presented. We found that as the size of the disparity increased, the magnitude of perceived depth increased, while the precision with which observers could make depth discrimination judgments decreased. Beyond an initial increase, depth realism decreased with increasing disparity magnitude. This decrease occurred well below the disparity limit required to ensure comfortable viewing.

Study on establishment and mechanics application of finite element model of bovine eye.

Science.gov (United States)

Cui, Yan-Hui; Huang, Ju-Fang; Cheng, Si-Ying; Wei, Wei; Shang, Lei; Li, Na; Xiong, Kun

2015-08-13

Glaucoma mainly induced by increased intraocular pressure (IOP), it was believed that the pressure that wall of eyeball withstands were determined by material properties of the tissue and stereoscopic geometry of the eyeball. In order to study the pressure changes in different parts of interior eyeball wall, it is necessary to develop a novel eye ball FEM with more accurate geometry and material properties. Use this model to study the stress changes in different parts of eyeball, especially the lamina cribrosa (LC) under normal physiological and pathological IOP, and provide a mathematical model for biomechanical studies of selected retinal ganglion cells (RGCs) death. (1) Sclera was cut into 3.8-mm wide, 14.5-mm long strips, and cornea was cut into 9.5-mm-wide and 10-mm-long strips; (2) 858 Mini BionixII biomechanical loading instrument was used to stretch sclera and cornea. The stretching rate for sclera was 0.3 mm/s, 3 mm/s, 30 mm/s, 300 mm/s; and for cornea were 0.3 mm/s and 30 mm/s. The deformation-stress curve was recorded; (3) Naso-temporal and longitudinal distance of LC were measured; (4) Micro-CT was used to accurately scan fresh bovine eyes and obtain the geometrical image and data to establish bovine eye model. 3-D reconstruction was performed using these images and data to work out the geometric shape of bovine eye; (5) IOP levels for eyeball FEM was set and the inner wall of eyeball was used taken as load-bearing part. Simulated eyeball FE modeling was run under the IOP level of 10 mmHg, 30 mmHg, 60 mmHg and 100 mmHg, and the force condition of different parts of eyeball was recorded under different IOP levels. (1) We obtained the material parameters more in line with physiological conditions and established a more realistic eyeball model using reversed engineering of parameters optimization method to calculate the complex nonlinear super-elastic and viscoelastic parameters more accurately; (2) We observed the following phenomenon by

The 2006 July 17 Java (Indonesia) tsunami from satellite imagery and numerical modelling: a single or complex source?

Science.gov (United States)

Hébert, H.; Burg, P.-E.; Binet, R.; Lavigne, F.; Allgeyer, S.; Schindelé, F.

2012-12-01

The Mw 7.8 2006 July 17 earthquake off the southern coast of Java, Indonesia, has been responsible for a very large tsunami causing more than 700 casualties. The tsunami has been observed on at least 200 km of coastline in the region of Pangandaran (West Java), with run-up heights from 5 to more than 20 m. Such a large tsunami, with respect to the source magnitude, has been attributed to the slow character of the seismic rupture, defining the event as a so-called tsunami earthquake, but it has also been suggested that the largest run-up heights are actually the result of a second local landslide source. Here we test whether a single slow earthquake source can explain the tsunami run-up, using a combination of new detailed data in the region of the largest run-ups and comparison with modelled run-ups for a range of plausible earthquake source models. Using high-resolution satellite imagery (SPOT 5 and Quickbird), the coastal impact of the tsunami is refined in the surroundings of the high-security Permisan prison on Nusa Kambangan island, where 20 m run-up had been recorded directly after the event. These data confirm the extreme inundation lengths close to the prison, and extend the area of maximum impact further along the Nusa Kambangan island (about 20 km of shoreline), where inundation lengths reach several hundreds of metres, suggesting run-up as high as 10-15 m. Tsunami modelling has been conducted in detail for the high run-up Permisan area (Nusa Kambangan) and the PLTU power plant about 25 km eastwards, where run-up reached only 4-6 m and a video recording of the tsunami arrival is available. For the Permisan prison a high-resolution DEM was built from stereoscopic satellite imagery. The regular basin of the PLTU plant was designed using photographs and direct observations. For the earthquake's mechanism, both static (infinite) and finite (kinematic) ruptures are investigated using two published source models. The models account rather well for the sea level

A parallel stereo reconstruction algorithm with applications in entomology (APSRA)

Science.gov (United States)

Bhasin, Rajesh; Jang, Won Jun; Hart, John C.

2012-03-01

We propose a fast parallel algorithm for the reconstruction of 3-Dimensional point clouds of insects from binocular stereo image pairs using a hierarchical approach for disparity estimation. Entomologists study various features of insects to classify them, build their distribution maps, and discover genetic links between specimens among various other essential tasks. This information is important to the pesticide and the pharmaceutical industries among others. When considering the large collections of insects entomologists analyze, it becomes difficult to physically handle the entire collection and share the data with researchers across the world. With the method presented in our work, Entomologists can create an image database for their collections and use the 3D models for studying the shape and structure of the insects thus making it easier to maintain and share. Initial feedback shows that the reconstructed 3D models preserve the shape and size of the specimen. We further optimize our results to incorporate multiview stereo which produces better overall structure of the insects. Our main contribution is applying stereoscopic vision techniques to entomology to solve the problems faced by entomologists.

Geomorphological mapping of shallow landslides using UAVs

Science.gov (United States)

Fiorucci, Federica; Giordan, Daniele; Dutto, Furio; Rossi, Mauro; Guzzetti, Fausto

2015-04-01

The mapping of event shallow landslides is a critical activity, due to the large number of phenomena, mostly with small dimension, affecting extensive areas. This is commonly done through aerial photo-interpretation or through field surveys. Nowadays, landslide maps can be realized exploiting other methods/technologies: (i) airborne LiDARs, (ii) stereoscopic satellite images, and (iii) unmanned aerial vehicles (UAVs). In addition to the landslide maps, these methods/technologies allow the generation of updated Digital Terrain Models (DTM). In December 2013, in the Collazzone area (Umbria, Central Italy), an intense rainfall event triggered a large number of shallow landslides. To map the landslides occurred in the area, we exploited data and images obtained through (A) an airborne LiDAR survey, (B) a remote controlled optocopter (equipped with a Canon EOS M) survey, and (C) a stereoscopic satellite WorldView II MS. To evaluate the mapping accuracy of these methods, we select two landslides and we mapped them using a GPS RTK instrumentation. We consider the GPS survey as the benchmark being the most accurate system. The results of the comparison allow to highlight pros and cons of the methods/technologies used. LiDAR can be considered the most accurate system and in addition it allows the extraction and the classification of the digital surface models from the surveyed point cloud. Conversely, LiDAR requires additional time for the flight planning, and specific data analysis user capabilities. The analysis of the satellite WorldView II MS images facilitates the landslide mapping over large areas, but at the expenses of a minor resolution to detect the smaller landslides and their boundaries. UAVs can be considered the cheapest and fastest solution for the acquisition of high resolution ortho-photographs on limited areas, and the best solution for a multi-temporal analysis of specific landslide phenomena. Limitations are due to (i) the needs of optimal climatic

Fall speed measurement and high-resolution multi-angle photography of hydrometeors in free fall

OpenAIRE

T. J. Garrett; C. Fallgatter; K. Shkurko; D. Howlett

2012-01-01

We describe here a new instrument for imaging hydrometeors in free fall. The Multi-Angle Snowflake Camera (MASC) captures high-resolution photographs of hydrometeors from three angles while simultaneously measuring their fall speed. Based on the stereoscopic photographs captured over the two months of continuous measurements obtained at a high altitude location within the Wasatch Front in Utah, we derive statistics for fall speed, hydrometeor size, shape, orientation and asp...

Fallspeed measurement and high-resolution multi-angle photography of hydrometeors in freefall

OpenAIRE

T. J. Garrett; C. Fallgatter; K. Shkurko; D. Howlett

2012-01-01

We describe here a new instrument for imaging hydrometeors in freefall. The Multi-Angle Snowflake Camera (MASC) captures high resolution photographs of hydrometeors from three angles while simultaneously measuring their fallspeed. Based on the stereoscopic photographs captured over the two months of continuous measurements obtained at a high altitude location within the Wasatch Front in Utah, we derive statistics for fallspeed, hydrometeor size, shape, orientation and aspect ratio. From a sel...

Hypervelocity impact of concrete

International Nuclear Information System (INIS)

Watson, A.J.; Anderson, W.F.; Archer, B.

1982-01-01

Blocks of concrete and various other materials were impacted by high speed copper jets at the centre of one face, the resulting transient phenomena were measured using ultra high speed photography and various electrical signal transducers. Measurements were made of the jet velocity, penetration rate, crack velocity and initiation time, and strain pulse propagation. Post test measurements were made using electron microscopy, ultra sonics and stereoscopic photography. (orig.) [de

Robotic technological aids in esophageal surgery

OpenAIRE

Rebecchi, Fabrizio; Allaix, Marco E.; Morino, Mario

2017-01-01

Robotic technology is an emerging technology that has been developed in order to overcome some limitations of the standard laparoscopic approach, offering a stereoscopic three-dimensional visualization of the surgical field, increased maneuverability of the surgical tools with consequent increased movement accuracy and precision and improved ergonomics. It has been used for the surgical treatment of most benign esophageal disorders. More recently, it has been proposed also for patients with o...

A fluid dynamics approach to bioreactor design for cell and tissue culture.

Science.gov (United States)

Dusting, Jonathan; Sheridan, John; Hourigan, Kerry

2006-08-20

The problem of controlling cylindrical tank bioreactor conditions for cell and tissue culture purposes has been considered from a flow dynamics perspective. Simple laminar flows in the vortex breakdown region are proposed as being a suitable alternative to turbulent spinner flask flows and horizontally oriented rotational flows. Vortex breakdown flows have been measured using three-dimensional Stereoscopic particle image velocimetry, and non-dimensionalized velocity and stress distributions are presented. Regions of locally high principal stress occur in the vicinity of the impeller and the lower sidewall. Topological changes in the vortex breakdown region caused by an increase in Reynolds number are reflected in a redistribution of the peak stress regions. The inclusion of submerged scaffold models adds complexity to the flow, although vortex breakdown may still occur. Relatively large stresses occur along the edge of disks jutting into the boundary of the vortex breakdown region. Copyright 2006 Wiley Periodicals, Inc.