To perform the image-based modeling (IBM) procedure, the parameters, inch as camera focus and principal point, are always needed by user input or by complicated calculation. A new computer vision based IBM method for ...
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ISBN:
(纸本)0780378652
To perform the image-based modeling (IBM) procedure, the parameters, inch as camera focus and principal point, are always needed by user input or by complicated calculation. A new computer vision based IBM method for building reconstruction is presented in this paper. It reconstructs the building models by projective reconstruction at first, and then makes use of-the surface features of buildings to complete the Euclidean reconstruction and optimizes the results. In view of the experiment results, the method recovers the 3-dimension information of the objects satisfactorily and has the advantages of simple operations and less additive information needed.
We cast the problem of inferring the 3D shape of a scene from a collection of defocused images in the framework of anisotropic diffusion. We propose a novel algorithm that can estimate the shape of a scene by inferrin...
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ISBN:
(纸本)0769519008
We cast the problem of inferring the 3D shape of a scene from a collection of defocused images in the framework of anisotropic diffusion. We propose a novel algorithm that can estimate the shape of a scene by inferring the diffusion coefficient of a heat equation. The method is optimal, as we pose it as the minimization of a certain cost functional based on the input images, and fast. Furthermore, we also extend our algorithm to the case of multiple images, and derive a 3D scene segmentation algorithm that can work in the presence of pictorial camouflage.
image-based modeling techniques permit the creation of visually interesting geometric models from photographs. But traditional image-based texturing (IBT) techniques often result in extracted textures of poor, uneven ...
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ISBN:
(纸本)9781581136456
image-based modeling techniques permit the creation of visually interesting geometric models from photographs. But traditional image-based texturing (IBT) techniques often result in extracted textures of poor, uneven quality. This paper introduces a novel technique to improve the quality of image-based textures. We compute a simple and efficient texture quality metric based on the Jacobian of the imaging transform. We identify the correlation between the values of the Jacobian metric and the levels of an image pyramid, allowing us to formulate a novel texture synthesis approach which operates over textures from 3D surfaces in a scene. Our technique allows the creation of uniform, high-resolution textures, relieving the user of the burden of collecting large numbers of images while increasing the visual quality of image-based models. This improved quality is important to create compelling visual experiences in interactive environments.
We present a generative model for isotropic bidirectional reflectance distribution functions (BRDFs) based on acquired reflectance data. Instead of using analytical reflectance models, we represent each BRDF as a dens...
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We present a generative model for isotropic bidirectional reflectance distribution functions (BRDFs) based on acquired reflectance data. Instead of using analytical reflectance models, we represent each BRDF as a dense set of measurements. This allows us to interpolate and extrapolate in the space of acquired BRDFs to create new BRDFs. We treat each acquired BRDF as a single high-dimensional vector taken from a space of all possible BRDFs. We apply both linear (subspace) and non-linear (manifold) dimensionality reduction tools in an effort to discover a lower-dimensional representation that characterizes our measurements. We let users define perceptually meaningful parametrization directions to navigate in the reduced-dimension BRDF space. On the low-dimensional manifold, movement along these directions produces novel but valid BRDFs.
We present a new set of techniques for modeling and animating realistic faces from photographs and videos. Given a set of face photographs taken simultaneously, our modeling technique allows the interactive recovery o...
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We present a new set of techniques for modeling and animating realistic faces from photographs and videos. Given a set of face photographs taken simultaneously, our modeling technique allows the interactive recovery of a textured 3D face model. By repeating this process for several facial expressions, we acquire a set of face models that can be linearly combined to express a wide range of expressions. Given a video sequence, this linear face model can be used to estimate the face position, orientation, and facial expression at each frame. We illustrate these techniques on several datasets and demonstrate robust estimations of detailed face geometry and motion.
Virtual Environment (VE) techniques provide a powerful tool for the visualization of the 3D environment of a teleoperation work site, particularly when "live" video display is inadequate for the task operati...
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ISBN:
(纸本)0819439800
Virtual Environment (VE) techniques provide a powerful tool for the visualization of the 3D environment of a teleoperation work site, particularly when "live" video display is inadequate for the task operation or its transmission is constrained, for example by limited bandwidth. However, the ability of VE to cope with the dynamic phenomena of typical teleoperation work sites is severely limited by its pre-defined model-based nature. Thus, an on-line composing mechanism is needed to make it environment compliant. For this purpose, this paper describes an on-line technique for camera calibration and an interactive VE modeling method that works on a single 2D image. Experiments have shown that the methods are convenient and effective for on-line VE editing.
This paper presents an overview of our efforts in modeling-from-realty to create virtual reality models through observation of real objects. These efforts span three aspects: how to create geometric models of virtual ...
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ISBN:
(纸本)0769509843;0769509851
This paper presents an overview of our efforts in modeling-from-realty to create virtual reality models through observation of real objects. These efforts span three aspects: how to create geometric models of virtual objects;how to create photometric models of virtual objects;and how to integrate such virtual objects with real scenes. For geometric model creation, we have developed a two-step method: simultaneous alignment and volumetric view merging. For photometric model creation, we have developed two methods, model-based and eigen-texture rendering methods, both of which automatically create models by observing the real objects. For the integration of virtual objects with real scenes, we have developed a method that renders virtual objects based on real illumination distribution. We have successfully tested the proposed methods by using real images to demonstrate their effectiveness.
We present a 3-D reconstruction method, which combines geometry-basedmodeling, image-based modeling and rendering techniques. The first component is an interactive geometry modeling method which recovery of the basic...
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ISBN:
(纸本)081944281X
We present a 3-D reconstruction method, which combines geometry-basedmodeling, image-based modeling and rendering techniques. The first component is an interactive geometry modeling method which recovery of the basic geometry of the photographed scene. The second component is model-based stereo algorithm. We discuss the image processing problems and algorithms of walking through in virtual space, then designs and implement a high performance multi-thread wandering algorithm. The applications range from architectural planning and archaeological reconstruction to virtual environments and cinematic special effects.
We present a two-step camera calibration process based on linear least squares formulations. We show how to apply this process to build an integrated modeling environment, in which a scene is modeled by having the use...
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ISBN:
(纸本)0818692162
We present a two-step camera calibration process based on linear least squares formulations. We show how to apply this process to build an integrated modeling environment, in which a scene is modeled by having the user specify, on a given image? a set of reference points (used for camera calibration) and object points (used for positioning the objects in the scene). Once this has been done, synthetic information can be superimposed onto the image and arbitrary views can be produced. Using this methodology, we developed Virtual Referee, an application to analyze soccer plays from still images, generating an OpenGL camera over a 3D field model.
We present a method to acquire the reflectance field of a human face and use these measurements to render the face under arbitrary changes in lighting and viewpoint. We first acquire images of the face from a small se...
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ISBN:
(纸本)1581132085
We present a method to acquire the reflectance field of a human face and use these measurements to render the face under arbitrary changes in lighting and viewpoint. We first acquire images of the face from a small set of viewpoints under a dense sampling of incident illumination directions using a light stage. We then construct a reflectance function image for each observed image pixel from its values over the space of illumination directions. From the reflectance functions, we can directly generate images of the face from the original viewpoints in any form of sampled or computed illumination. To change the viewpoint, we use a model of skin reflectance to estimate the appearance of the reflectance functions for novel viewpoints. We demonstrate the technique with synthetic renderings of a person's face under novel illumination and viewpoints.
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