07-04-2011, 03:50 PM
Submitted By
G.Vinuthana
[attachment=11870]
1. Abstract:
The past people only dream about communicating geographically but the advancement in telecommunication along with advancement in media techniques make it possible. But still there was struggle to make them collaborate in a real time world, like efforts to have users share the same physical space, during there meetings, conferences, etc. National Tele-Immersion Initiative – NTII team leads the way to make all these things possible. They are working on projects to have users share the same physical space in a real time world, as if they are sitting in front of each other in the same room. In this regard Advanced Network & Services played a vital role, to bring together the experts in this field close together. This team is lead by Jargon Lanier, Who was one of the pioneers in development of Virtual Reality (which according to him is “the brain anticipates a virtual world instead of the physical one”) in 1980’s. National Tele-Immersion team started there work in middle of 1997 and the collaborating schools were Brown University, Providence Naval Post guard School , Monterey University of North Carolina, Chapel Hill and University of Pennsylvania, Philadelphia.
In start the main aim of the team was to take into account the ultimate synthesis of media technologies for the scanning and tracking of three dimensional environments. Based on vision based three dimensional reconstruction with the help of new advancement in fields like media technologies, networking, robotics. In May 2000 whole the hectic efforts of the team cope up with some success, with first demonstration of three years long work. National TeleImmersion Initiative team lead by virtual reality pioneer Jargon Lanier, conducted which at one stage was just imagination. This effort lead to the thinking which could change the way we communicate over long distances, people could feel each other submerge together in the same physical space. The experiment was conducted in Chapel Hill led by UNC computer scientists Henry Fuchs and Greg Welch. It linked UNC Chapel Hill, the University of Pennsylvania in
Philadelphia and Advanced Network & Services at New York. Researchers at each place could feel themselves in the office of their colleagues hundreds of miles far apart. The apparatus of the test consisted of two large walls, projection cameras and head tracking gear. One screen was at left side of Welch and other was on right. Through left wall Welch can see his colleagues at Philadelphia and through other of New York. He can peep in and out and images change accordingly, like when he leaned forward images grew larger and become smaller when he moved back. At each target site there were digital cameras to capture the image and laser rangefinders to gather information regarding the position of the object. Computer then converted them into a three dimensional information which was then transmitted to Chapel Hill via Internet2, where computers were mounted to reconstruct the image and display that on the screen.
To some point it seems that Tele-Immersion is another kind of Virtual Reality but Jargons Lanier is of other view. According to him “virtual reality allows people to move around in a preprogrammed representation of a 3D environment, whereas tele-immersion is more like photography. It's measuring the real world and conveying the results to the sensory system
2. REQUIREMENTS FOR IMMERSIVE TELECONFERENCE SYSTEMS:
To meet the requirements of immersion, it is absolutely necessary to use a large Display that covers almost the whole viewing angle of the visual system. In addition, the large display has to be integrated into the usual workspace of an office or a meeting room. Thus, the most practicable solution is a desktop-like arrangement with large flat screens like plasma displays with a diagonal of 50 inch and more. Starting from such a desktop-like system and taking into account results from intensive human factors research, further requirements on the presentation of the scene can be formulated as follows:
• Conferees are seamlessly integrated in the scene and displayed with at least head, shoulders, torso and arms in natural life-size
• All visual parameters of the scene and the different sources have to be harmonized
• The perspective of the scene is permanently adapted to the current viewpoint of the conferee in front of the display (head motion parallax; look-behind effect)
• Eye-contact between two partners talking to each other has to be provided
• Gaze from one conferee to another has to be reproduced in a sufficient manner such that everybody can recognize who is looking at whom (e.g.: who is searching for eye contact)
• Voice of a conferee must come from the same direction where he is positioned on
the screen.
3. SHARED TABLE ENVIRONMENT:
A very attractive way to meet the above requirements is to follow the principle of a share table environment. It is based on the idea to position the participants consistently in a virtual environment around a shared table. At the transmitting side the conferee in front of the display is captured by multiple cameras and a 3D image of the conferee is derived from this multitier set-up. The 3D images of all participating conferees are then placed virtually around a shared table. Ideally, this is done in a isotropic manner in order to obtain social symmetry. Hence, in the case of three-party conference the participants form a equilateral triangle. In the case of four parties it would be a square, an equilateral pentagon for a five-party system, and so on. At the receiving end this entirely composed 3D scene is rendered onto the 2D display of the terminal by using a virtual camera. The position of the virtual camera coincides with the current position of the conferee's head. For this purpose the head position is permanently registered by head tracker and the virtual camera is moved with the head. Thus, supposing that the geometrical parameters of the multi-view capture device, the virtual scene and the virtual camera are well fitted to each other, it is ensured that all conferees see the scene under the right perspective view, even while changing their own viewing position. As the consequence, they can also change the view knowingly in order to watch the scene from another perspective, to look behind objects or to look at a previously occluded object. Moreover, all deviations of the conferees' position from a default position are picked up by the multi-view capture devices. Thus, again supposing well fitted geometrical relations, the 3D image will be moved equivalently in the virtual world and, as a consequence, the other conferees can follow the resulting perspective changes at their displays. These circumstances ensure a natural reproduction of eye-contacts and body language in the case of direct face-to-face communication between two partners as well as a natural perspective of this bilateral communication from the position of the third conferee. Last, but not least - the isotropic scene composition and the resulting symmetry enable that the displays can be also placed symmetrically between the partners (i.e. at the middle of the direct viewing axis). Thus, the display works similar to a mirror. Hence, all portrayals appear well balanced in natural life-size at the displays and a psychologically dominance of particular participants is avoided.
G.Vinuthana
[attachment=11870]
1. Abstract:
The past people only dream about communicating geographically but the advancement in telecommunication along with advancement in media techniques make it possible. But still there was struggle to make them collaborate in a real time world, like efforts to have users share the same physical space, during there meetings, conferences, etc. National Tele-Immersion Initiative – NTII team leads the way to make all these things possible. They are working on projects to have users share the same physical space in a real time world, as if they are sitting in front of each other in the same room. In this regard Advanced Network & Services played a vital role, to bring together the experts in this field close together. This team is lead by Jargon Lanier, Who was one of the pioneers in development of Virtual Reality (which according to him is “the brain anticipates a virtual world instead of the physical one”) in 1980’s. National Tele-Immersion team started there work in middle of 1997 and the collaborating schools were Brown University, Providence Naval Post guard School , Monterey University of North Carolina, Chapel Hill and University of Pennsylvania, Philadelphia.
In start the main aim of the team was to take into account the ultimate synthesis of media technologies for the scanning and tracking of three dimensional environments. Based on vision based three dimensional reconstruction with the help of new advancement in fields like media technologies, networking, robotics. In May 2000 whole the hectic efforts of the team cope up with some success, with first demonstration of three years long work. National TeleImmersion Initiative team lead by virtual reality pioneer Jargon Lanier, conducted which at one stage was just imagination. This effort lead to the thinking which could change the way we communicate over long distances, people could feel each other submerge together in the same physical space. The experiment was conducted in Chapel Hill led by UNC computer scientists Henry Fuchs and Greg Welch. It linked UNC Chapel Hill, the University of Pennsylvania in
Philadelphia and Advanced Network & Services at New York. Researchers at each place could feel themselves in the office of their colleagues hundreds of miles far apart. The apparatus of the test consisted of two large walls, projection cameras and head tracking gear. One screen was at left side of Welch and other was on right. Through left wall Welch can see his colleagues at Philadelphia and through other of New York. He can peep in and out and images change accordingly, like when he leaned forward images grew larger and become smaller when he moved back. At each target site there were digital cameras to capture the image and laser rangefinders to gather information regarding the position of the object. Computer then converted them into a three dimensional information which was then transmitted to Chapel Hill via Internet2, where computers were mounted to reconstruct the image and display that on the screen.
To some point it seems that Tele-Immersion is another kind of Virtual Reality but Jargons Lanier is of other view. According to him “virtual reality allows people to move around in a preprogrammed representation of a 3D environment, whereas tele-immersion is more like photography. It's measuring the real world and conveying the results to the sensory system
2. REQUIREMENTS FOR IMMERSIVE TELECONFERENCE SYSTEMS:
To meet the requirements of immersion, it is absolutely necessary to use a large Display that covers almost the whole viewing angle of the visual system. In addition, the large display has to be integrated into the usual workspace of an office or a meeting room. Thus, the most practicable solution is a desktop-like arrangement with large flat screens like plasma displays with a diagonal of 50 inch and more. Starting from such a desktop-like system and taking into account results from intensive human factors research, further requirements on the presentation of the scene can be formulated as follows:
• Conferees are seamlessly integrated in the scene and displayed with at least head, shoulders, torso and arms in natural life-size
• All visual parameters of the scene and the different sources have to be harmonized
• The perspective of the scene is permanently adapted to the current viewpoint of the conferee in front of the display (head motion parallax; look-behind effect)
• Eye-contact between two partners talking to each other has to be provided
• Gaze from one conferee to another has to be reproduced in a sufficient manner such that everybody can recognize who is looking at whom (e.g.: who is searching for eye contact)
• Voice of a conferee must come from the same direction where he is positioned on
the screen.
3. SHARED TABLE ENVIRONMENT:
A very attractive way to meet the above requirements is to follow the principle of a share table environment. It is based on the idea to position the participants consistently in a virtual environment around a shared table. At the transmitting side the conferee in front of the display is captured by multiple cameras and a 3D image of the conferee is derived from this multitier set-up. The 3D images of all participating conferees are then placed virtually around a shared table. Ideally, this is done in a isotropic manner in order to obtain social symmetry. Hence, in the case of three-party conference the participants form a equilateral triangle. In the case of four parties it would be a square, an equilateral pentagon for a five-party system, and so on. At the receiving end this entirely composed 3D scene is rendered onto the 2D display of the terminal by using a virtual camera. The position of the virtual camera coincides with the current position of the conferee's head. For this purpose the head position is permanently registered by head tracker and the virtual camera is moved with the head. Thus, supposing that the geometrical parameters of the multi-view capture device, the virtual scene and the virtual camera are well fitted to each other, it is ensured that all conferees see the scene under the right perspective view, even while changing their own viewing position. As the consequence, they can also change the view knowingly in order to watch the scene from another perspective, to look behind objects or to look at a previously occluded object. Moreover, all deviations of the conferees' position from a default position are picked up by the multi-view capture devices. Thus, again supposing well fitted geometrical relations, the 3D image will be moved equivalently in the virtual world and, as a consequence, the other conferees can follow the resulting perspective changes at their displays. These circumstances ensure a natural reproduction of eye-contacts and body language in the case of direct face-to-face communication between two partners as well as a natural perspective of this bilateral communication from the position of the third conferee. Last, but not least - the isotropic scene composition and the resulting symmetry enable that the displays can be also placed symmetrically between the partners (i.e. at the middle of the direct viewing axis). Thus, the display works similar to a mirror. Hence, all portrayals appear well balanced in natural life-size at the displays and a psychologically dominance of particular participants is avoided.
