3D Interaction System with Multiple Identified,Small,Wireless,Battery-less,Occlusion-free Magnetic Markers

Tohoku University北村喜

The effects of changing projection geometry on perception of 3D objects on and around tabletops

Funding: Natural Sciences and Engineering Research Council of Canada Networks of Centres of Excellence of Canada.Displaying 3D objects on horizontal displays can cause problems in the way that the virtual scene is presented on the 2D surface; inappropriate choices in how 3D is represented can lead to distorted images and incorrect object interpretations. We present four experiments that test 3D perception. We varied projection geometry in three ways: type of projection (perspective/parallel), separation between the observer’s point of view and the projection’s center (discrepancy), and the presence of motion parallax (with/without parallax). Projection geometry had strong effects different for each task. Reducing discrepancy is desirable for orientation judgments, but not for object recognition or internal angle judgments. Using a fixed center of projection above the table reduces error and improves accuracy in most tasks. The results have far-reaching implications for the design of 3D views on tables, in particular for multi-user applications where projections that appear correct for one person will not be perceived correctly by another.PostprintPeer reviewe

Acceleration Techniques for Photo Realistic Computer Generated Integral Images

The research work presented in this thesis has approached the task of accelerating the generation of photo-realistic integral images produced by integral ray tracing. Ray tracing algorithm is a computationally exhaustive algorithm, which spawns one ray or more through each pixel of the pixels forming the image, into the space containing the scene. Ray tracing integral images consumes more processing time than normal images. The unique characteristics of the 3D integral camera model has been analysed and it has been shown that different coherency aspects than normal ray tracing can be investigated in order to accelerate the generation of photo-realistic integral images. The image-space coherence has been analysed describing the relation between rays and projected shadows in the scene rendered. Shadow cache algorithm has been adapted in order to minimise shadow intersection tests in integral ray tracing. Shadow intersection tests make the majority of the intersection tests in ray tracing. Novel pixel-tracing styles are developed uniquely for integral ray tracing to improve the image-space coherence and the performance of the shadow cache algorithm. Acceleration of the photo-realistic integral images generation using the image-space coherence information between shadows and rays in integral ray tracing has been achieved with up to 41 % of time saving. Also, it has been proven that applying the new styles of pixel-tracing does not affect of the scalability of integral ray tracing running over parallel computers. The novel integral reprojection algorithm has been developed uniquely through geometrical analysis of the generation of integral image in order to use the tempo-spatial coherence information within the integral frames. A new derivation of integral projection matrix for projecting points through an axial model of a lenticular lens has been established. Rapid generation of 3D photo-realistic integral frames has been achieved with a speed four times faster than the normal generation

Practical Processing Techniques for Magnetic 3D Motion Tracking

Tohoku University北村喜文課

A family of stereoscopic image compression algorithms using wavelet transforms

With the standardization of JPEG-2000, wavelet-based image and video compression technologies are gradually replacing the popular DCT-based methods. In parallel to this, recent developments in autostereoscopic display technology is now threatening to revolutionize the way in which consumers are used to enjoying the traditional 2-D display based electronic media such as television, computer and movies. However, due to the two-fold bandwidth/storage space requirement of stereoscopic imaging, an essential requirement of a stereo imaging system is efficient data compression. In this thesis, seven wavelet-based stereo image compression algorithms are proposed, to take advantage of the higher data compaction capability and better flexibility of wavelets. [Continues.

A family of stereoscopic image compression algorithms using wavelet transforms

With the standardization of JPEG-2000, wavelet-based image and video compression technologies are gradually replacing the popular DCT-based methods. In parallel to this, recent developments in autostereoscopic display technology is now threatening to revolutionize the way in which consumers are used to enjoying the traditional 2D display based electronic media such as television, computer and movies. However, due to the two-fold bandwidth/storage space requirement of stereoscopic imaging, an essential requirement of a stereo imaging system is efficient data compression. In this thesis, seven wavelet-based stereo image compression algorithms are proposed, to take advantage of the higher data compaction capability and better flexibility of wavelets. In the proposed CODEC I, block-based disparity estimation/compensation (DE/DC) is performed in pixel domain. However, this results in an inefficiency when DWT is applied on the whole predictive error image that results from the DE process. This is because of the existence of artificial block boundaries between error blocks in the predictive error image. To overcome this problem, in the remaining proposed CODECs, DE/DC is performed in the wavelet domain. Due to the multiresolution nature of the wavelet domain, two methods of disparity estimation and compensation have been proposed. The first method is performing DEJDC in each subband of the lowest/coarsest resolution level and then propagating the disparity vectors obtained to the corresponding subbands of higher/finer resolution. Note that DE is not performed in every subband due to the high overhead bits that could be required for the coding of disparity vectors of all subbands. This method is being used in CODEC II. In the second method, DEJDC is performed m the wavelet-block domain. This enables disparity estimation to be performed m all subbands simultaneously without increasing the overhead bits required for the coding disparity vectors. This method is used by CODEC III. However, performing disparity estimation/compensation in all subbands would result in a significant improvement of CODEC III. To further improve the performance of CODEC ill, pioneering wavelet-block search technique is implemented in CODEC IV. The pioneering wavelet-block search technique enables the right/predicted image to be reconstructed at the decoder end without the need of transmitting the disparity vectors. In proposed CODEC V, pioneering block search is performed in all subbands of DWT decomposition which results in an improvement of its performance. Further, the CODEC IV and V are able to perform at very low bit rates(< 0.15 bpp). In CODEC VI and CODEC VII, Overlapped Block Disparity Compensation (OBDC) is used with & without the need of coding disparity vector. Our experiment results showed that no significant coding gains could be obtained for these CODECs over CODEC IV & V. All proposed CODECs m this thesis are wavelet-based stereo image coding algorithms that maximise the flexibility and benefits offered by wavelet transform technology when applied to stereo imaging. In addition the use of a baseline-JPEG coding architecture would enable the easy adaptation of the proposed algorithms within systems originally built for DCT-based coding. This is an important feature that would be useful during an era where DCT-based technology is only slowly being phased out to give way for DWT based compression technology. In addition, this thesis proposed a stereo image coding algorithm that uses JPEG-2000 technology as the basic compression engine. The proposed CODEC, named RASTER is a rate scalable stereo image CODEC that has a unique ability to preserve the image quality at binocular depth boundaries, which is an important requirement in the design of stereo image CODEC. The experimental results have shown that the proposed CODEC is able to achieve PSNR gains of up to 3.7 dB as compared to directly transmitting the right frame using JPEG-2000

Rendering and display for multi-viewer tele-immersion

Video teleconferencing systems are widely deployed for business, education and personal use to enable face-to-face communication between people at distant sites. Unfortunately, the two-dimensional video of conventional systems does not correctly convey several important non-verbal communication cues such as eye contact and gaze awareness. Tele-immersion refers to technologies aimed at providing distant users with a more compelling sense of remote presence than conventional video teleconferencing. This dissertation is concerned with the particular challenges of interaction between groups of users at remote sites. The problems of video teleconferencing are exacerbated when groups of people communicate. Ideally, a group tele-immersion system would display views of the remote site at the right size and location, from the correct viewpoint for each local user. However, is is not practical to put a camera in every possible eye location, and it is not clear how to provide each viewer with correct and unique imagery. I introduce rendering techniques and multi-view display designs to support eye contact and gaze awareness between groups of viewers at two distant sites. With a shared 2D display, virtual camera views can improve local spatial cues while preserving scene continuity, by rendering the scene from novel viewpoints that may not correspond to a physical camera. I describe several techniques, including a compact light field, a plane sweeping algorithm, a depth dependent camera model, and video-quality proxies, suitable for producing useful views of a remote scene for a group local viewers. The first novel display provides simultaneous, unique monoscopic views to several users, with fewer user position restrictions than existing autostereoscopic displays. The second is a random hole barrier autostereoscopic display that eliminates the viewing zones and user position requirements of conventional autostereoscopic displays, and provides unique 3D views for multiple users in arbitrary locations

Proposition des modèles et de processus structurés pour le développement d’environnements collaboratifs synchrones : application aux réunions de revue de conception

Development of collaborative environment is a complex process. The complexity lies in the fact that collaborative environment development involves a lot of decision making. Several tradeoffs need to be made to satisfy current and future requirements from a potentially various set of user profiles. The handling of these complexities poses challenges for researcher, developers and companies. The knowledge required to make suitable design decisions and to rigorously evaluate those design decisions is usually broad, complex, and evolving. In Part-I of this thesis we investigate to formulate the general knowledge about: synchronous collaborative work which conceptualize the problem domain, synchronous collaborative environment which conceptualize the solution domain and synchronous collaborative environment evaluation which conceptualize the evaluation of whole or part of the proposed solution for the specified problem. This formulation has been done through literature study and leaded to the Concept Maps. The results generate three models: SyCoW (synchronous collaborative work), SyCoE (synchronous collaborative environment) and SyCoEE (synchronous collaborative environment evaluation). In Part-II of this thesis we proposed a process for selection/development of collaborative environment, where we demonstrate how SyCoW, SyCoE and SyCoEE support this process in different ways. Through the proposed process we present the development of new synchronous collaborative environment for design review meeting, named, MT-DT. MT-DT has been designed, developed and evaluated by the author in her PhD. MT-DT consist of a multi-touch table with specific 3D software application which support collaborative design review activities. The results of evaluation confirmed the usability of MT-DT and provide arguments for our choices which we made during development of MT-DT.Le développement d'un environnement collaboratif est un processus complexe. La complexité réside dans le fait que ce développement implique beaucoup de prise de décisions. De multiples compromis doivent être faits pour répondre aux exigences actuelles et futures d'utilisateurs aux profils variés. La prise en compte de cette complexité pose des problèmes aux chercheurs, développeurs et utilisateurs. Les informations et données requises pour prendre des décisions adéquates de conception et évaluer rigoureusement ces décisions sont nombreuses, parfois indéterminées et en constante évolution. Dans la partie-I de cette thèse, nous formulons les connaissances générales sur le travail collaboratif synchrone qui constituent l'état de l'art du domaine du problème. Nous pratiquons de même pour les environnements collaboratifs synchrones (domaine de la solution technique) et leur cette formulation s'appuie sur une étude de la littérature et conduit à la proposition de Schéma Conceptuel (Concept Maps). Nous en déduisons trois modèles: SyCoW (travail collaboratif synchrone), SyCoE (environnement collaboratif synchrone) et SyCoEE (évaluation environnement collaboratif synchrone). Dans la partie II de cette thèse, nous proposons un processus pour la sélection / développement d'un environnement collaboratif, où nous démontrons comment les modèles SyCoW, SyCoE et SyCoEE structurent ce processus. Grâce à la mise en œuvre de la démarche proposée, nous présentons le développement d'un nouvel environnement collaboratif synchrone pour une réunion de revue de conception nommé MT-DT. MT-DT a été conçu, développé et évalué par l'auteur dans sa thèse de doctorat. MT-DT est une application logicielle 3D spécifique à une table multi-touche qui assiste les activités de revue de conception collaborative. Les résultats de l'évaluation ont confirmé la convivialité de MT-DT et fournissent des éléments de validation des choix que nous avons faits au cours du développement de MT-DT

Supporting collocated and at-a-distance experiences with TV and VR displays

Televisions (TVs) and VR Head-Mounted Displays (VR HMDs) are used in shared and social spaces in the home. This thesis posits that these displays do not sufficiently reflect the collocated, social contexts in which they reside, nor do they sufficiently support shared experiences at-a-distance. This thesis explores how the role of TVs and VR HMDs can go beyond presenting a single entertainment experience, instead supporting social and shared use in both collocated and at-a-distance contexts. For collocated TV, this thesis demonstrates that the TV can be augmented to facilitate multi-user interaction, support shared and independent activities and multi-user use through multi-view display technology, and provide awareness of the multi-screen activity of those in the room, allowing the TV to reflect the social context in which it resides. For at-a-distance TV, existing smart TVs are shown to be capable of supporting synchronous at-a-distance activity, broadening the scope of media consumption beyond the four walls of the home. For VR HMDs, collocated proximate persons can be seamlessly brought into mixed reality VR experiences based on engagement, improving VR HMD usability. Applied to at-a-distance interactions, these shared mixed reality VR experiences can enable more immersive social experiences that approximate viewing together as if in person, compared to at-a-distance TV. Through an examination of TVs and VR HMDs, this thesis demonstrates that consumer display technology can better support users to interact, and share experiences and activities, with those they are close to