[[alternative]]Research on Synchronization Problem between Geometry-Based VR and Panoramic-Based VR Systems

計畫編號：NSC88-2213-E032-010研究期間：199808~199907研究經費：471,000[[sponsorship]]行政院國家科學委員

Virtual viewpoint three-dimensional panorama

Conventional panoramic images are known to provide for an enhanced field of view in which the scene always has a fixed appearance. The idea presented in this paper focuses on the use of the concept of virtual viewpoint creation to generate different panoramic images of the same scene with three-dimensional component. Three-dimensional effect in a resultant panorama is realized by superimposing a stereo-pair of panoramic images

Image Mosaicing and Producing a Panoramic Visibility

Aim of this research paper is to take multiple input images , the input images are having some of the overlapped region with one another. Since digital cameras cant take photos of a wider view, for a wider view we need a highly sophisticated camera. It is therefore being attempted to develop enabling methodology which can convert the corresponding images captured form such cameras into a panoramic view. In this paper a n algorithm is used and applied some of the advanced function available in matlab to make this work much more efficient

Single-Strip Triangulation of Manifolds with Arbitrary Topology

Triangle strips have been widely used for efficient rendering. It is NP-complete to test whether a given triangulated model can be represented as a single triangle strip, so many heuristics have been proposed to partition models into few long strips. In this paper, we present a new algorithm for creating a single triangle loop or strip from a triangulated model. Our method applies a dual graph matching algorithm to partition the mesh into cycles, and then merges pairs of cycles by splitting adjacent triangles when necessary. New vertices are introduced at midpoints of edges and the new triangles thus formed are coplanar with their parent triangles, hence the visual fidelity of the geometry is not changed. We prove that the increase in the number of triangles due to this splitting is 50% in the worst case, however for all models we tested the increase was less than 2%. We also prove tight bounds on the number of triangles needed for a single-strip representation of a model with holes on its boundary. Our strips can be used not only for efficient rendering, but also for other applications including the generation of space filling curves on a manifold of any arbitrary topology.Comment: 12 pages, 10 figures. To appear at Eurographics 200

Real-Time Panoramic Tracking for Event Cameras

Event cameras are a paradigm shift in camera technology. Instead of full frames, the sensor captures a sparse set of events caused by intensity changes. Since only the changes are transferred, those cameras are able to capture quick movements of objects in the scene or of the camera itself. In this work we propose a novel method to perform camera tracking of event cameras in a panoramic setting with three degrees of freedom. We propose a direct camera tracking formulation, similar to state-of-the-art in visual odometry. We show that the minimal information needed for simultaneous tracking and mapping is the spatial position of events, without using the appearance of the imaged scene point. We verify the robustness to fast camera movements and dynamic objects in the scene on a recently proposed dataset and self-recorded sequences.Comment: Accepted to International Conference on Computational Photography 201

Automating joiners

Pictures taken from different view points cannot be stitched into a geometrically consistent mosaic, unless the structure of the scene is very special. However, geometrical consistency is not the only criterion for success: incorporating multiple view points into the same picture may produce compelling and informative representations. A multi viewpoint form of visual expression that has recently become highly popular is that of joiners (a term coined by artist David Hockney). Joiners are compositions where photographs are layered on a 2D canvas, with some photographs occluding others and boundaries fully visible. Composing joiners is currently a tedious manual process, especially when a great number of photographs is involved. We are thus interested in automating their construction. Our approach is based on optimizing a cost function encouraging image-to-image consistency which is measured on point-features and along picture boundaries. The optimization looks for consistency in the 2D composition rather than 3D geometrical scene consistency and explicitly considers occlusion between pictures. We illustrate our ideas with a number of experiments on collections of images of objects, people, and outdoor scenes

Spherical Panoramas, and non Metric Images for Long Range Survey, the San Barnaba Spire, Sagrada Familia, Barcelona, Spain

The Sagrada Familia by Gaudi in Barcelona about 80 years after the death of its creator is going quickly to take its final shape as well as, maintain its original form as Gaudi would have wanted, the actual builders say.  Complicated and elaborated forms, following the construction layout of the Chapel of Colonia Guell in Santa Coloma, tend to reproduce, on a gigantic scale, the organic forms of trees going to draw the charming and attractive complex of the small church derived from the model of wires used by Gaudi for its design. It has been long debated, and still it is debated on this approach as "camouflage", how it is consistent with the attitude of Gaudi architecture in the sense that he saw a sort of self-generating form of architecture during its own construction gradually responding to the stress placed by the same growth of structures, shapes, and materials. ("We do not reproduce the forms but we are able to reproduce a character owing its spirit,” A. Gaudi). But beyond this, the reality remains of the gradual suppression of what Gaudi realized until his death. Basically the sole facade of the Nativity, with its striking features and ending with four original towers as hyperboloids pinnacles with glittering glazed mosaics, is the only one that was finished by Gaudi himself, in particular the San Barnaba’s spire. In this action of progressive “destruction”, it is very important to analyze, survey and plot what realized by Gaudi for recovering the original forms and keeping them in their Gaudian formal and constructive features. The spire of St. Barnabas is one of the most architecturally significant occurrence of the whole building and its survey poses major technical problems: their possible solution represented by the experience here shown, has been already experimented in the previous 90 years as one of the first applications of expeditious photogrammetric techniques of survey (Clini, Fangi,1990). The technical problems consist basically in the difficulty given by its height above the street level, about 100 meters. Long focal lenses have to be used to get a suitable resolution and accuracy. We wanted to repeat now the survey using a different photogrammetric technique from the old one, that was DLT algorithm for non-metric images. The new technique is the Spherical Photogrammetry. Multi-image Spherical Photogrammetry makes use as sensor of a pseudo-image that is the spherical panorama, composed by the images taken from the same station point. For details of Spherical Photogrammetry see (Fangi, 2,3,4,9). A particular procedure appropriate for the orientation of very narrow field of view lenses panorama has been already set up and used for the orientation and plotting of the three minarets of the Great Mosque of Omayyad’s in Damascus, Syria. Their heights range from 60 to 80 meters above the courtyard pavement of the mosque. The technique consists in taking different focal lengths panorama from the same station point (Fangi, New Castle, 2010), one with WA wide angle and another one with NA Narrow Angle, adding to the stability of WA panorama the resolution of NA panorama. The same approach has been used in the Sagrada Familia, for the survey of San Barnaba’s spire. In 1990 the A. made a survey of the same spire. But in comparison to the years 90, there is one difficulty more: now the rear of the spire is not visible because of the construction of the roof of the church, while it was visible in 1990. The solution has been then to use the original images taken in the years 90 for the rear of the spire and the spherical panoramas for the rest, i.e. the part toward the façade, using the original control points. Then we had to make a combined adjustment of non metric images using DLT approach and spherical photogrammetry algorithms. The restitution has been indeed carried out using both type of imagery, spherical panorama and non metric images. The results are satisfactory in the sense that the principles of quick photogrammetry have been respected: short surveying times, simple and inexpensive tools, reaching in a ny case suitable outcome