As well known, in the reconstruction of the 3d models through optical systems, the errors are due to the single-view acquisition error and to the 3d modeling procedure. The latter can be ascribed to the various phases...
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ISBN:
(纸本)0769522238
As well known, in the reconstruction of the 3d models through optical systems, the errors are due to the single-view acquisition error and to the 3d modeling procedure. The latter can be ascribed to the various phases of the 3d modeling pipeline: pairwise registration, global registration, surface integration. This work examines the acquisition error as well as the errors due to an automatic procedure recently proposed for the 3d modeling of dental plaster casts. This contribution derives a simple error propagation model, rather useful for practical simulation purposes. From a general viewpoint, this contribution proposes a useful simulation of error propagation in 3d modeling, it shows the quality of an automatic 3d modeling procedure recently proposed and it shows the accuracy of 3d modeling dental plaster casts by current commercial range cameras an the considered automatic method.
We present a novel range sensing method that is capable of constructing accurate 3d models of specular objects. Our method utilizes a new range imaging concept called multi-peak range imaging, which accounts for the e...
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ISBN:
(纸本)0769522238
We present a novel range sensing method that is capable of constructing accurate 3d models of specular objects. Our method utilizes a new range imaging concept called multi-peak range imaging, which accounts for the effects of mutual reflections. False measurements generated by mutual reflections are then eliminated by applying a series of constraint tests based on local smoothness, global coordinate consistency and visibility consistency. We show the usefulness of our method by applying the method to three real objects with specular surfaces. The ground truth data for those three objects were also acquired in order to evaluate the elimination of false measurements and to justify the selection of the parameters in the constraint tests. Experimental results indicate that our method significantly improves upon the traditional methods for constructing reliable 3d models of specular objects with complex shapes.
If several laboratories work in the same field and need to cooperate, it is necessary to exchange and mutually compare their computer results. The quick way to solve this problem is to unite their file formats (if it ...
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ISBN:
(纸本)0769522238
If several laboratories work in the same field and need to cooperate, it is necessary to exchange and mutually compare their computer results. The quick way to solve this problem is to unite their file formats (if it is practicable) or to install new software systems, which are data or file format compatible. A much better solution is to use only one common system. This article describes the architecture of a new client-server system, which offers possibilities of effective cooperation for laboratories doing the research in the field of the spatial organization of human genome. However, the system design is determined mainly by optical microscopy principles and therefore the system can easily be modified for use in other applications or environments. The most pressing problem during the system design was how to share and process large 3d image data in client-server architecture.
Image Compression has received a lot of interest over the years. Almost all the compression algorithms and standards, discussed in literature, gather statistics and compress on the complete image and compresses to sui...
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ISBN:
(纸本)0769522238
Image Compression has received a lot of interest over the years. Almost all the compression algorithms and standards, discussed in literature, gather statistics and compress on the complete image and compresses to suit various requirements such as lossy/lossless, baseline/progressive, spatial, region on interest. Natural images such as - gray scale images and color images are best compressed in the existing literature based on the local and global properties such as attributes of constituent pixels of the given image. In this paper, it is proposed to quantize the amplitudes of pixel values to form a number of bit planes and these bit planes are transmitted in either lossy, lossless, progressive manner. Bit plane formation is attempted from the image acquiring stage to compress and then to transmission stage. Results obtained are promising and give rise to new method or ideology in image sensing, acquiring, storage andtransmission.
General information about a class of objects, such as human faces or teeth, can help to solve the otherwise ill-posed problem of reconstructing a complete surface from sparse 3d feature points or 2d projections of poi...
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ISBN:
(纸本)0769522238
General information about a class of objects, such as human faces or teeth, can help to solve the otherwise ill-posed problem of reconstructing a complete surface from sparse 3d feature points or 2d projections of points. We present a technique that uses a vector space representation of shape (3d Morphable Model) to infer missing vertex coordinates. Regularization derived from a statistical approach makes the system stable and robust with respect to noise by computing the optimal tradeoff between fitting quality and plausibility. We present a direct, non-iterative algorithm to calculate this optimum efficiently, and a method for simultaneously compensating unknown rigid transformations. The system is applied and evaluated in two different fields: (1) reconstruction of 3d faces at unknown orientations from 2d feature points at interactive rates, and (2) restoration of missing surface regions of teeth for CAd-CAM production of dental inlays and other medical applications.
This paper presents a framework for dynamic 3d shape and motion reconstruction from multi-viewpoint images using a deformable mesh model. By deforming a mesh at a frame to that at the next frame, we can obtain both 3d...
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ISBN:
(纸本)0769522238
This paper presents a framework for dynamic 3d shape and motion reconstruction from multi-viewpoint images using a deformable mesh model. By deforming a mesh at a frame to that at the next frame, we can obtain both 3d shape and motion of the object simultaneously. The deformation process of our mesh model is heterogeneous. Each vertex changes its deformation process according to its 1) photometric property (i.e., if it has prominent texture or not), and 2) physical property (i.e., if it is an element of rigid part of the object or not). This heterogeneous deformation model enables us to reconstruct the object which consists of different kinds of materials or parts with different motion models, e.g., rigidly acting body parts anddeforming soft clothes or its skins, by a single and unified computational framework.
It is well known that many surfaces exhibit reflectance that is not well modelled by Lambert's law. This is the case not only for surfaces that are rough or shiny, but also those that are matte and composed of mat...
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ISBN:
(纸本)0769522238
It is well known that many surfaces exhibit reflectance that is not well modelled by Lambert's law. This is the case not only for surfaces that are rough or shiny, but also those that are matte and composed of materials that are particle suspensions. As a result, standard Lambertian shape-from-shading methods can not be applieddirectly to the analysis of rough and shiny surfaces. In order to overcome this difficulty, in this paper, we consider how to reconstruct the Lambertian component for rough and shiny surfaces when the object is illuminated in the viewing direction. To do this we make use of the diffuse reflectance models described by Oren and Nayar, and by Wolff. Our experiments with synthetic and real-worlddata reveal the effectiveness of the correction method, leading to improved surface normal and height recovery.
Manual indexing of large databases of geometric information is costly and often impracticable. Because of this research into retrieval and indexing schemes has focused on the development of various 3d to 2d mappings t...
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ISBN:
(纸本)0769522238
Manual indexing of large databases of geometric information is costly and often impracticable. Because of this research into retrieval and indexing schemes has focused on the development of various 3d to 2d mappings that characterise a shape as a histogram with a small number of parameters. Many methods of generating such 2d signatures (i.e. histograms) have been proposed, generally based on geometric measures of say curvature or distance. However these geometric signatures lack information about topology and tend to become indistinct as the complexity of the shape increases. This paper describes a new method for characterising both the geometry and topology of shapes in a single 2d graph, the Surface Partitioning Spectrum (SPS). We evaluate the effectiveness of using the SPS with a Neural Network to assess the similarity of shapes within a test set.
The present paper proposes a novel method for 3d-model watermarking for indexing. The proposed approach is based on the use of a Generalized Radon Transformation. More specifically, the Cylindrical Integration Transfo...
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ISBN:
(纸本)0769522238
The present paper proposes a novel method for 3d-model watermarking for indexing. The proposed approach is based on the use of a Generalized Radon Transformation. More specifically, the Cylindrical Integration Transform (CIT) is initially applied to the 3d models in order to produce descriptor vectors. At the same time a watermarking technique, based on CIT is used in order to embed a specific model identifier in the nodes of the 3d model. This identifier links the model to its descriptor vector, which is extracted only once and stored in a database. Every time this model is employed as a query model, watermark detection is used so as to retrieve the corresponding identifier and further the descriptor vector, which can be further used in a matching algorithm. The proposed techniques are evaluated experimentally in terms of both watermarking efficiency and content-based retrieval performance.
In this paper a new technique for 3d acoustic image segmentation and modelling is proposed. Especially, in the underwater environment, in which optical sensors suffer from visibility problems, the acoustical devices m...
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ISBN:
(纸本)0769522238
In this paper a new technique for 3d acoustic image segmentation and modelling is proposed. Especially, in the underwater environment, in which optical sensors suffer from visibility problems, the acoustical devices may provide efficient solutions, but, on the other hand, acoustic image interpretation is surely more difficult for a human operator The proposed application involves the use of an acoustic camera which directly acquires images structured as a set of 3d points. due to the noisy nature of this type of data, the segmentation problem becomes more challenging and the standard algorithms for range image segmentation are likely to fail. The proposed method is based on a simplified version of the so called recover and select paradigm in which the seed areas, front which the segmentation starts, are generated by adopting a robust approach based on the RANSAC (RANdom Sample And Consensus) algorithm. Superquadric primitives are directly recovered from raw data without any pre-segmentation processing. Experimental trials using both synthetic and real acoustical images confirm the goodness of the method, and a large robustness of the resulting segmented images, associated to a relatively low computational load.
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