We present a web-based prototype for the interactive search of items in quality electronic catalogues. Once a subset of images meeting the user39;s information needs have been identified, these images can be display...
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This paper presents a hybrid (geometry- & image-based) technique suitable for providing interactive walkthroughs of large, complex outdoor scenes. Motion is restricted along a smooth predefined path and the input ...
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ISBN:
(纸本)0769522238
This paper presents a hybrid (geometry- & image-based) technique suitable for providing interactive walkthroughs of large, complex outdoor scenes. Motion is restricted along a smooth predefined path and the input to the system is a sparse set of stereoscopic views at certain points (key-positions) along that path (one view per position). An approximate local 3d model is constructed from each view, capable of capturing photometric and geometric properties of the scene only locally. Then during the rendering process, a continuous morphing (both photometric & geometric) takes place between successive local 3d models, using what we call a "morphable 3d-model". The morphing proceeds in a physically-valid way. For this reason, a wide-baseline image matching technique is proposed, handling cases where the wide baseline between the two images is mainly due to a looming of the camera. Our system can be extended in the event of multiple stereoscopic views (and therefore multiple local models) per key-position of the path (related by a camera rotation). In that case one local 3d-mosaic (per key-position) is constructed comprising all local 3d models therein and a "morphable 3d-mosaic" is usedduring the rendering process. A partial-differential equation is adopted to handle the problem of geometric consistency of each 3d-mosaic.
We investigate the relationship between camera design and3d photography, by examining the influence of camera design on the estimation of the motion and structure of a scene from video data. To compute the 3d structu...
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ISBN:
(纸本)0769515215;0769515223
We investigate the relationship between camera design and3d photography, by examining the influence of camera design on the estimation of the motion and structure of a scene from video data. To compute the 3d structure of a scene accurately from a moving vision sensor, we need to be able to estimate the motion of the sensor from the recorded image information, a problem that has been well-studied. By relating the differential structure of the time varying plenoptic function to different known and new camera designs, we can establish a hierarchy of cameras based upon the stability and complexity of the computations necessary to estimate structure and motion. At the low end of this hierarchy is the standard planar pinhole camera for which the structure from motion problem is non-linear and ill-posed. At the high end is a camera, which we call the full field of view polydioptric camera, for which the problem is linear and stable. In between are multiple view cameras with a large field of view which we have built, as well as omni-directional sensors. We develop design suggestions for a polydioptric camera especially suited for 3d photography, and we propose a linear algorithm utilizing this camera design to recover the structure of the scene.
Interactive 3d modeling is the process of building a 3d model of an object or a scene in real-time while the 3d (range) data is acquired. This is possible only if the computational complexity of all involved algorithm...
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We present a surface compression method that stores surfaces as wavelet-compressed signed-distance volumes. Our approach enables the representation of surfaces with complex topology and arbitrary numbers of components...
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ISBN:
(纸本)0769515215;0769515223
We present a surface compression method that stores surfaces as wavelet-compressed signed-distance volumes. Our approach enables the representation of surfaces with complex topology and arbitrary numbers of components within a single multiresolution data structure. This data structure elegantly handles topological modification at high compression rates. Our methoddoes not require the costly and sometimes infeasible base mesh construction step required by subdivision surface approaches, We present several improvements over previous attempts at compressing signed-distance functions, including an O(n) distance transform, a zero set initialization method for triangle meshes, and a specialized thresholding algorithm. We demonstrate the potential of sampleddistance volumes for surface compression and progressive reconstruction for complex high genus surfaces.
We consider the following data fusion problem. A 3d object with textured Lambertian surface is measured and independently photographed. A triangulated model of the object and two uncalibrated images are obtained. The ...
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ISBN:
(纸本)0769522238
We consider the following data fusion problem. A 3d object with textured Lambertian surface is measured and independently photographed. A triangulated model of the object and two uncalibrated images are obtained. The goal is to precisely register the images to the model. Solving this problem is necessary for building a geometrically accurate, photorealistic model from laser-scanned3ddata and high quality images. Recently, we have proposed a novel method that generalises the photo-consistency approach by Clarkson et al. [2] to the case of uncalibrated cameras, when both intrinsic and extrinsic parameters are unknown. This gives a user the freedom of taking the pictures by a conventional digital camera, from arbitrary positions and with varying zoom. The method is based on manual pre-registration followed by a genetic optimisation algorithm. A brief description of the pilot version of the method [8] has been given together with the results of a few initial tests. In this paper, we report on some new significant developments in this project. The critical issue of robustness against illumination changes is addressed and various colour representations and cost functions are tested and compared Natural constraints are introduced and experimentally validated to simplify the camera model and accelerate the algorithm. Finally, we present synthetic and real data with ground truth, apply the improved method to the data and measure the quality of the results.
In this paper we present a new color structured light technique based on a disordered codeword strategy. The aim of this method is to recover 3d information in moving scenes in such a way that the correspondence probl...
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ISBN:
(纸本)0769522238
In this paper we present a new color structured light technique based on a disordered codeword strategy. The aim of this method is to recover 3d information in moving scenes in such a way that the correspondence problem is easily and robustly solved. With this goal in mind a six-connectivity topology has been introduced in our pattern and color features have been inserted on it. Repetition anddisorder are allowed in the codeword which implies that the Hamming distance between contiguous codewords increases. As a consequence of that, code loss circumstances can be efficiently handled. Additionally, computational cost is the code recovering phase is highly reduced since codewords are defined (is sets. A structured light projection system has been built in our lab and a wide test under real moving conditions has been carried out. This experimentation has been performed on medium resolution and for slow movements specifications giving promising results.
This paper deals with the automatic stereo reconstruction of wide-area scenes. Its particular goal is a computationally efficient method that can be performed on a personal computer, despite the large amount of data i...
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We present a hierarchical and robust algorithm addressing the problem of filtering and segmentation of three-dimensional acoustic images. This algorithm is based on the tensor voting approach - a unified computational...
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ISBN:
(纸本)0769515223
We present a hierarchical and robust algorithm addressing the problem of filtering and segmentation of three-dimensional acoustic images. This algorithm is based on the tensor voting approach - a unified computational framework for the inference of multiple salient structures. Unlike most previous approaches, no models or prior information of the underwater environment, nor the intensity information of acoustic images is considered in this algorithm. Salient structures and outlier noisy points are directly clustered in two steps according to both the density and the structural information of input data. Our experimental trials show promising results, very robust despite the low computational complexion.
different file formats for storage and manipulation of volumetric data exist today, but none of them has been accepted as a standard by the volume visualization and volume graphics communities until now. This paper tr...
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